BUILDING TECHNOLOGIES PROGRAM

September 2011 • PNNL-20890

VOLUME 16.

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40% Whole-House 

Energy Savings in the 

Mixed-Humid Climate

PREPARED BY

Pacific Northwest National Laboratory 

& Oak Ridge National Laboratory

September 2011

MIXED-HUMID CLIMATE

BUILDING AMERICA BEST PRACTICES SERIES
This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the 

United States Government nor any agency thereof, nor Battelle Memorial Institute, nor any of their employees, makes any 

warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of 

any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. 

Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise 

does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any 

agency thereof, or Battelle Memorial Institute. The views and opinions of authors expressed herein do not necessarily state or 

reflect those of the United States Government or any agency thereof.
BUILDING AMERICA BEST PRACTICES SERIES

VOLUME 16.

40% Whole-House 

Energy Savings in the 

Mixed-Humid Climate

PREPARED BY

Pacific Northwest National Laboratory

Michael C. Baechler

TL Gilbride, MG Hefty, PC Cole, K Adams, RS Butner and SJ Ortiz

Oak Ridge National Laboratory

Pat M. Love

September 2011

Prepared for the U.S. Department of Energy

under Contract DE-AC05-76RLO 1830

PNNL-20890

Preface

This best practices guide is the 16th in a series of guides for builders 

produced by the U.S. Department of Energy’s Building America 

program. This guidebook is a resource to help builders design and 

construct homes that are among the most energy efficient available, 

while addressing issues such as building durability, indoor air quality, 

and occupant health, safety, and comfort. With the measures described 

in this guide, builders in the mixed-humid climate can build homes 

that have whole-house energy savings of 40% over the Building 

America benchmark with no added overall costs for consumers. 

The best practices described in this guide are based on the results 

of research and demonstration projects conducted by Building 

America’s research teams. Building America brings together the 

nation’s leading building scientists with over 300 production builders 

to develop, test, and apply innovative, energy-efficient construction 

practices. Building America builders have found they can build 

homes that meet these aggressive energy-efficiency goals at no net 

increased costs to the homeowners. The recommendations in this 

guide will help builders achieve Home Energy Rating (HERS) 

scores of 70 or lower. 

This guide represents a step up from our first mixed-humid best 

practices guide (Volume 4. Builders and Buyers Handbook for 

Improving New Home Efficiency, Comfort, and Durability in the 

Mixed-Humid Climate), which aimed at achieving energy-efficiency 

savings of 15% above the Building America benchmark (a home built 

to the 1993 Model Energy Code, the code in effect when the program 

began). The Building America research projects described in this guide 

achieve energy savings of 40% greater than the Building America (1993 

MEC) benchmark home. 

The national energy and building codes are revised on a 3-year 

cycle. The recommendations in this document meet or exceed 

the requirements of the 2009 International Energy Conservation 

Code (IECC) and the 2009 International Residential Code (IRC). 

Starting in fiscal year (FY) 2011, Building America research projects 

began using the 2009 IECC as the benchmark for analysis of home 

energy efficiency. The 2009 IECC requirements are shown in green 

throughout this guide. The 2009 IECC requirements represent a 

15% improvement over the 2006 IECC. The provisions of the 2012 

IECC were finalized at the Final Action Hearings in November 2010 

and published in June 2011. New requirements in the 2012 IECC 

are shown in comparison tables throughout this guide. The 2012 

requirements represent a 15% improvement over the 2009 IECC.

You can learn more about Building America 

and download additional copies of this 

document, other best practice guides, 

research reports, and case studies at 

www.buildingamerica.gov

“By improving energy efficiency 

in homes, you are literally putting 

dollar bills back into the pockets 

of homeowners.” 

Steven Chu, U.S. Energy Secretary, 

addressing builders in New Orleans, 

November 9, 2010

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The Building America recommendations 

provided in this guide meet or exceed the 

code requirements of the 2009 International 

Energy Conservation Code (2009 IECC) 

and the 2009 International Residential 

Code (2009 IRC), which are noted in tables 

and green text throughout this guide. 

Requirements of the 2012 IECC and IRC 

have also been indicated throughout this 

guide. Builders should note that local code 

provisions always take precedence over 

these recommendations.

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 i

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BUILDING AMERICA BEST PRACTICES SERIES
ii Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011

BUILDING AMERICA BEST PRACTICES SERIES
Acknowledgments

The U.S. Department of Energy’s Building America program 

comprises public-private partnerships that conduct systems research 

to improve overall housing performance, increase housing durability 

and comfort, reduce energy use, and increase energy security for 

America’s homeowners. Program activities focus on finding solutions 

for both new and existing homes, as well as integrating clean onsite 

energy systems that will allow the homebuilding industry to provide 

homes that produce more energy than they use. In addition to 

the DOE management and staff, the Building America program 

includes several research teams, four DOE national laboratories, and 

hundreds of builders, contractors, architect and engineering firms, 

manufacturers, and energy service providers. Building America 

also co-manages the ENERGY STAR program along with the U.S. 

Environmental Protection Agency, and works with other federal 

agencies to coordinate research efforts and disseminate findings. 

Together, all of these partners make the program a valuable source 

of knowledge and innovation for U.S. homebuilders. 

The DOE Building America program funded the development 

of this series of guides. DOE also funded the Building America 

national laboratories and research teams that conducted the research 

described in this best practices guide. These teams are listed to the 

right. In FY 2011, the list of Building America research teams 

was expanded to 14 teams. (See www.eere.energy.gov/buildings/

building_america/research_teams.html for a full list of the current 

teams). The research teams have taken on the hard work of applying 

research, field testing, training builders, and transforming results 

into best practices. Most of the drawings, descriptions, photos, and 

case studies in these guides originated with these research partners. 

Hundreds of builders across the country have chosen to work with 

Building America and its partners on research projects to further our 

understanding of building science. These builders deserve thankful 

recognition for their dedication to continually improving the 

quality and energy efficiency of the homes they build and for their 

contributions to our understanding of how buildings work. Four 

builders from the mixed-humid climate are showcased in case studies 

in this document: Insight Homes, Seaford, Delaware; Pine Mountain 

Builders, Pine Mountain, Georgia; Tindall Homes, Princeton, New 

Jersey; and Urbane Homes, Crestwood, Kentucky. Examples from 

these and other mixed-humid climate builders are used throughout 

the document to illustrate construction best practices. 

FY 2010 Building America 

Research Teams

These Building America research teams partner with 

all segments of the building industry to conduct 

research and demonstration projects that develop, 

analyze, and test strategies and technologies 

for improving building performance and energy 

efficiency. Building America teams who participated 

in the preparation of this document included

Building America Industrialized 

Housing Partnership 

led by the Florida Solar Energy Center

www.baihp.org

Building Industry Research Alliance 

led by ConSol www.bira.ws

Building Science Consortium 

led by Building Science Corporation

www.buildingscienceconsulting.com

Consortium for Advanced 

Residential Buildings 

led by Steven Winter Associates, Inc.

www.carb-swa.com/index.html

Integrated Building and 

Construction Solutions

www.ibacos.com

National Association of Home 

Builders Research Center 

www.nahbrc.com

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 iii

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BUILDING AMERICA BEST PRACTICES SERIES
Several national laboratories participated in this project. Pacific 

Northwest National Laboratory and Oak Ridge National Laboratory 

coordinated the writing and production of this document. The 

National Renewable Energy Laboratory made its library of Building 

America documents available to the authors, reviewed this guide, 

and posted it to the Web. Scientists at Lawrence Berkeley National 

Laboratory reviewed the document as well.

The authors and DOE wish to thank all of the many contributors 

who have made this project a success. We would especially like 

to thank graphic artist Christina Van Vleck who designed this 

document and prepared many of its illustrations.

iv Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011

BUILDING AMERICA BEST PRACTICES SERIES
Contents

Chapter 1. Welcome ..................................................................................... 1.1

Chapter 2. The Business Case for Building High-Performance Homes...................... 2.1

Builders and Building America ...................................................................... 2.1

The Business Case for Energy Efficiency......................................................... 2.2

Consumer Preferences .............................................................................. 2.2

Competitive Advantage ............................................................................. 2.3

Cost-Neutral Energy Savings ....................................................................... 2.4

Codes as Drivers ..................................................................................... 2.10

Chapter 3. Business Management Tools........................................................... 3.1

Quality Management .................................................................................. 3.1

Building America Quality Management Guidelines ................................................ 3.4

The Costs of Quality Management.................................................................. 3.4

Implementing Quality Management ................................................................ 3.6

Integrated Design.................................................................................... 3.10

Traditional Design Processes....................................................................... 3.12

Integrated Design Process ......................................................................... 3.12

Value Engineering .................................................................................... 3.15

Process Overview................................................................................... 3.15

Reducing Construction Costs While Improving Functionality.................................... 3.15

Managing Innovation with Prototypes........................................................... 3.16

Chapter 4. Selling Performance..................................................................... 4.1

Branding and Labeling................................................................................ 4.1

Training Sales Staff ................................................................................... 4.3

Marketing Energy Efficiency........................................................................ 4.4

Reaching Out to the Media ......................................................................... 4.5

Chapter 5. The Mixed-Humid Climate.............................................................. 5.1

Design Considerations for the Mixed-Humid Climate.......................................... 5.2

Building America Examples of Weather-Resistant Construction in the Mixed-Humid Climate.... 5.3

Climate Description – Mixed-Humid............................................................... 5.4

Weather................................................................................................. 5.5

Flooding ............................................................................................. 5.5

Stormwater Management ........................................................................... 5.7 

Hurricanes and High Winds ......................................................................... 5.7 

Considering Solar Gain in Siting and Design .................................................... 5.9

Overhangs .......................................................................................... 5.10

Windows ............................................................................................. 5.11

Shading .............................................................................................. 5.11

Moss................................................................................................. 5.12

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 v

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BUILDING AMERICA BEST PRACTICES SERIES
Chapter 6. Building Science and the Systems Approach ....................................6.1

The Systems Approach .............................................................................. 6.1

Building Science Basics............................................................................... 6.1

Water................................................................................................. 6.3

Vapor................................................................................................. 6.3

Air Flow .............................................................................................. 6.5

Heat Transfer......................................................................................... 6.6

Occupants ........................................................................................... 6.8

Chapter 7. The Overall Building Envelope ........................................................ 7.1

Advanced Framing .................................................................................... 7.1

Insulation ................................................................................................ 7.5

Air Sealing.............................................................................................. 7.10

ENERGY STAR Thermal Enclosure Checklist ....................................................... 7.11

Chapter 8. Building Envelope Sub-Assemblies.................................................. 8.1

Foundation Assemblies............................................................................... 8.1

Controlling Liquid Water in Foundations ............................................................ 8.1

Frost Heave and Adfreeze .......................................................................... 8.4

Controlling Water Vapor in Foundations ........................................................... 8.5

Controlling Air Infiltration in Foundations.......................................................... 8.6

Controlling Heat Flow in Foundations .............................................................. 8.6

Slab Foundation Insulation.......................................................................... 8.7

Crawlspace Insulation ............................................................................... 8.9

Basement Insulation................................................................................ 8.10

Controlling Other Foundation Issues .............................................................. 8.10

Wall Assemblies....................................................................................... 8.12

Controlling Liquid Water in Walls.................................................................. 8.12

Controlling Water Vapor in Walls .................................................................. 8.15

Controlling Air Infiltration in Wall Assemblies..................................................... 8.16

Controlling Heat Flow in Walls .................................................................... 8.20

Roof Assemblies ..................................................................................... 8.21

Controlling Liquid Water in Roof/Attic Assemblies ............................................... 8.21

Controlling Water Vapor in Roof/Attic Assemblies ............................................... 8.22

Controlling Air Flow in Roof/Attic Assemblies .................................................... 8.22

Controlling Heat Flow in Roof/Attic Assemblies .................................................. 8.23

Window and Door Assemblies .................................................................... 8.25

Chapter 9. Mechanical, Plumbing, and Electrical Systems................................... 9.1

Heating and Cooling .................................................................................. 9.1

Heating and Cooling Equipment Sizing ............................................................ 9.2

Central Gas-Fired Furnaces ......................................................................... 9.3

Electric Heating and Heat Pumps................................................................... 9.3

Ductless Heat Pumps................................................................................ 9.4

Ground-Source Heat Pumps ........................................................................ 9.5

Cooling Equipment .................................................................................. 9.5

Dehumidifiers ........................................................................................ 9.7

Natural Cooling Strategies .......................................................................... 9.7

Ducts and Air Handlers ............................................................................. 9.10

Duct System Design and Layout ................................................................... 9.10

Duct Sealing and Insulating ......................................................................... 9.11

Pressure Balancing ................................................................................. 9.14

Air Distribution Fans................................................................................ 9.15

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BUILDING AMERICA BEST PRACTICES SERIES
Ventilation............................................................................................. 9.15

Supply-Only Ventilation Systems .................................................................. 9.15

Exhaust-Only Ventilation........................................................................... 9.16

Balanced Systems .................................................................................. 9.17

Plumbing and Water Heating...................................................................... 9.19

Hot Water Distribution ............................................................................ 9.20

Hot Water Circulation Pumps and Controls ...................................................... 9.20

Water Heaters ...................................................................................... 9.21

Swimming Pools ................................................................................... 9.24

High-Performance Lighting........................................................................ 9.25

CFLs and LEDs ..................................................................................... 9.25

Recessed Can Lights .............................................................................. 9.26

Appliances ............................................................................................ 9.27

EnergyGuide Label ................................................................................. 9.27

ENERGY STAR Label ............................................................................... 9.27

Chapter 10. Occupant Health and Safety ....................................................... 10.1

Chapter 11. Inspecting, Testing, and Commissioning ......................................... 11.1

Walk-Throughs during Construction ............................................................... 11.1

Building Commissioning............................................................................. 11.2

Pre-Dry Wall Inspection and Duct Pressure Testing ............................................... 11.2

Whole-House Pressure Testing and HERS Rating.................................................. 11.3

SNAPSHOT Form .................................................................................... 11.3

Chapter 12. Construction Site Documents, Scheduling, and Training ..................... 12.1

Construction and Contract Documents........................................................... 12.1

Contract Documents ............................................................................... 12.2

Change Orders...................................................................................... 12.3

Scheduling ............................................................................................ 12.3

Training Installers ................................................................................... 12.5

Training Tips from Mixed-Humid Climate Builders ................................................ 12.5

Training Opportunities ............................................................................. 12.6

HotSpot Inspections and Training ................................................................. 12.6

Chapter 13. Durability and Energy-Efficiency Checklist .................................... 13.1

Foundation Assemblies.............................................................................. 13.1

Controlling Moisture in All Foundation Types ...................................................... 13.1

Controlling Heat Flow in Slab Foundations ....................................................... 13.3

Controlling Heat Flow in Crawlspace Foundations ............................................... 13.3

Controlling Heat Flow in Basement Foundations ................................................. 13.3

Controlling Air Infiltration in All Foundation Types ............................................... 13.4

Other Foundation Issues ........................................................................... 13.4

Wall Assemblies...................................................................................... 13.5

Controlling Liquid Water in Wall Assemblies...................................................... 13.5

Controlling Water Vapor in Wall Assemblies ...................................................... 13.5

Controlling Air Infiltration in Wall Assemblies..................................................... 13.6

Controlling Heat Flow in Wall Assemblies......................................................... 13.6

Roof Assemblies ..................................................................................... 13.7

Controlling Liquid Water in Roof/Attic Assemblies ............................................... 13.7

Controlling Water Vapor in Roof/Attic Assemblies ............................................... 13.7

Controlling Air Flow in Roof/Attic Assemblies .................................................... 13.7

Controlling Heat Flow in Roof/Attic Assemblies .................................................. 13.7

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BUILDING AMERICA BEST PRACTICES SERIES
Whole-House Air Leakage ........................................................................ 13.8

Mechanical Systems ................................................................................ 13.8

Heating and Cooling Equipment................................................................... 13.8

Ducts ................................................................................................ 13.9

Ventilation ......................................................................................... 13.10

Plumbing........................................................................................... 13.10

Electrical ............................................................................................ 13.11

Occupant Health and Safety ....................................................................... 13.11

Commissioning ....................................................................................... 13.11

Chapter 14. Field Guides for Installers ........................................................... 14.1

Advanced Framing .................................................................................. 14.3

Foundation System Insulation, Moisture, and Air Leakage Control ........................ 14.7

Building Profiles: Mixed-Humid Climate......................................................... 14.11

Masonry Construction.............................................................................. 14.15

Housewrap ........................................................................................... 14.17

Window Flashing ................................................................................... 14.19

Wall-to-Roof Flashing.............................................................................. 14.21

Interior Air Sealing ................................................................................. 14.23

Exterior Air Sealing with Insulating Sheathing Panels....................................... 14.27

Plumbing Air Sealing............................................................................... 14.29

Electrical Air Sealing ............................................................................... 14.31

Installing Fiberglass Batt Insulation............................................................. 14.33

Installing Windows in Walls with External Rigid Foam Insulation......................... 14.35

Duct Location........................................................................................ 14.39

Air Handler and Duct Sealing.....................................................................14.43

Ductless Heat Pumps...............................................................................14.45

Roof Fascia/Soffit Vent Detail.................................................................... 14.47

Ice Dam Prevention................................................................................ 14.49

Case Studies ............................................................................................. CS.1

Insight Homes, Seaford, DE ............................................................................ 1

Pine Mountain Builders, Pine Mountain, GA......................................................... 1

Tindall Homes, Princeton, NJ .......................................................................... 1

Urbane Homes, Crestwood, KY........................................................................ 1

Appendices

I. Homebuyer’s Checklist ............................................................................ A1.1

II. DOE Building Energy Code Resource Center Code Notes................................ A2.1

III. Energy & Housing Glossary .................................................................... A3.1

IV. Acronyms and Abbreviations.................................................................. A4.1

viii Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011

BUILDING AMERICA BEST PRACTICES SERIES
“We just keep getting busier and busier.”

Abe Gilbert, co-owner, Urbane Homes, Louisville, Kentucky

Constructing energy-efficient, durable, and comfortable homes 

makes economic sense—for the builder, the consumer, the real 

estate professional, and the environment. In a time of significant 

challenges for the real estate community, Building America builders 

have made an important discovery—their homes are selling while 

their competitors’ homes are not. Builders also report fewer 

callbacks and complaints. Instead, buyers are calling to thank them 

for lower utility bills. Builders of all sizes are discovering the benefits 

of learning from Building America. In fact, all 10 of the nation’s 

10 largest builders in 2010 were Building America partners. 

Learn what hundreds of builders across the country have already 

discovered—it’s good for business to build energy-efficient homes that 

are more healthy, durable, and comfortable to live in, while cutting 

energy bills nearly in half. Building America will help show you how. 

This guide can help you apply Building America research to your 

own projects to achieve energy savings of 40% over the Building 

America benchmark (a home built to the 1993 Model Energy Code 

[MEC]). You will read about builders in the mixed-humid climate 

who are using these whole-house building principles to exceed the 

2009 International Energy Conservation Code (2009 IECC) and, 

in some cases, the 2012 IECC. Whether you’re a large production 

builder with managers, sales staff, designers, site superintendents, 

and installers on your staff, or a custom builder wearing many of 

these hats yourself, this guide can help you understand and apply 

the latest building science to differentiate yourself in a struggling 

new-construction market.

Chapter 1.

Welcome

Chapter 1. Welcome 

Argument for Energy-Efficient Construction

Chapter 2. The Business Case 

Chapter 3. Business Management Tools 

Chapter 4. Selling Performance 

Mixed-Humid Climate Building Science Basics

Chapter 5. The Mixed-Humid Climate 

Chapter 6. Building Science 

Design Recommendations

Chapter 7. Building Envelope 

Chapter 8. Sub-Assemblies 

Chapter 9. Mechanical/Plumbing/ Electrical 

Chapter 13. Checklist 

Installation Guidance 

Chapter 10. Health and Safety

Chapter 11. Inspecting, Testing, 

and Commissioning

Chapter 12. Construction Site Documents

Chapter 14. Field Guides for Installers

Case Studies: 

• Insight Homes, Seaford, DE

• Pine Mountain Builders, Pine Mountain, GA

• Tindall Homes, Princeton, NJ

• Urbane Homes, Crestwood, KY

Appendices:

I. Homebuyer’s Checklist

II. DOE Code Notes

III. Glossary

IV. Acronyms

1.1

CHAPTER 1. WELCOME

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 1.1
The 2009 International Energy 

Conservation Code (IECC) and 2009 

International Residential Code (IRC) 

mandate a significant increase in energy 

efficiency in new home construction. 

Changes in these codes represent an 

approximate 15% improvement in energy 

efficiency over the 2006 IECC. This guide 

will help builders meet and exceed these 

new requirements. The 2009 IECC and 

2009 IRC requirements are noted in green 

throughout this guide. The provisions of 

the 2012 IECC were published in June 2011 

and are now available for adoption by the 

states. New requirements in the 2012 IECC 

are listed in Chapter 2. These 2012 IECC 

requirements and energy-related 2012 IRC 

changes are shown in comparison tables in 

Chapter 8 and are also shown in green text 

throughout this guide.

Urbane Homes’ dollar sales volume has 

doubled every year since they started 

building, and they’ve already had repeat 

buyers who sold their original Urbane 

homes at a significant profit.

Break open this guide and you’ll find the following:

Chapters 2 through 4 provide the data to make the case to upper 

management, yourself, and your shareholders for the value of energyefficient construction, including research on consumer preferences, 

competitive advantage, and incentives. Here you’ll also find business 

management tools, sales training tips, and marketing strategies. 

Chapters 5 and 6 explain the whole-house approach to building science 

and special considerations for building in the mixed-humid climate. 

Chapters 7 through 9 provide construction recommendations to 

architects and engineers based on Building America research, with 

guidance on best practices for moisture management, insulation, 

and air sealing of home foundations, walls, and roofs. Guidance is 

also provided on windows, heating, air conditioning, ventilation, 

plumbing, and electrical systems. 

Occupant safety and health related to equipment and materials 

are discussed in Chapter 10. Chapter 11 provides guidance on 

inspecting and commissioning. Chapter 12 covers construction 

contracts, scheduling, and training. Chapter 13 provides a useful 

checklist of all of these recommendations. Chapter 14 provides 

handy two-page how-to field guides on specific energy-efficiency 

measures for installers.

Throughout these chapters, real-life examples are highlighted from 

exceptional builders in the mixed-humid climate. Case studies at the 

back of this guide tell how four builders achieved significant energy 

savings using Building America practices. 

See the appendices for a homebuyers’ checklist, DOE resources for 

meeting codes, a glossary, and acronym list.

For More Information

You can learn more about Building America and download additional copies 

of this document, other best practices, case studies, and research reports at 

www.buildingamerica.gov.

CHAPTER 1 / BUILDING AMERICA BEST PRACTICES SERIES

1.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
The number one reason identified by builders for building energyefficient homes is to differentiate themselves from their competition 

(NAHBRC 2007). Builders who use Building America principles are 

among the most successful in the United States today.

Builders and Building America

Building America has worked with production builders since 1995 

to improve the energy efficiency, durability, comfort, environmental 

performance, and quality of new homes. The Building America teams 

have conducted field research with builders throughout the country 

to test techniques, materials, and processes in real-world situations. 

As of June 2011, the program has contributed directly to the energyefficient construction of more than 42,200 homes, and builders and 

vendors that have worked with Building America have influenced 

over a million new homes. 

The nation’s ten largest builders are Building America partners, 

based on Builder Magazine’s Builder 100 list of the top 100 builders 

of 2010 (which ranks builders by home sale closings). Twenty-one of 

Building America’s more than 300 builder partners made the top 100 

list. While new home starts stayed low and many builders closed their 

doors, eight of Building America’s partners moved up in the rankings 

and eight more partners held their positions on the Builder 100 list. 

Qualifying for programs such as DOE’s Builders Challenge and 

ENERGY STAR provides an easy way to show consumers that 

your company’s homes are a cut above the competition.

Chapter 2.

The Business Case 

for Building HighPerformance Homes

“In today’s economy, firms that 

specialize in green or serve this 

market are seeing a tremendous 

advantage—and they’re doing 

good at the same time. Green 

building leads to healthier places 

for us to live and work in, lower 

energy and water use, and 

better profitability.” 

Harvey M. Bernstein, vice president, 

McGraw-Hill Construction

CHAPTER TOPICS

2.1 Builders and Building America

2.2 The Business Case for 

Energy Efficiency

2.10 Codes as Drivers

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Learn more about Building America at 

www.buildingamerica.gov.

2.1

CHAPTER 2. THE BUSINESS CASE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 2.1
The Business Case for Energy Efficiency

The world of new home construction is not the same place it was 

five years ago. The pace of new construction is still down in most 

markets. The good news is the public’s awareness of energy efficiency 

is up and, in most markets around the country, builders who 

emphasize energy-efficient construction have found that they are 

outselling their competition. 

The business case for high-performance, energy-efficient 

construction is straightforward and is based on the following points:

1. Consumers prefer energy-efficient homes.

2. Builders can use energy efficiency and other high-performance 

features to gain competitive advantage. Consumer preference and 

competitive advantage lead to more and faster sales.

3. Building America homes can meet energy-efficiency goals at no 

net increased costs to homeowners when added costs are balanced 

with utility savings.

4. New state and federal building codes are now a driving force 

in energy-efficient construction and Building America can help 

builders meet or exceed the new requirements.

Consumer Preferences

McGraw Hill Construction reports that the U.S. green building 

market is accelerating at a dramatic rate. According to their Green 

Outlook 2011 report, the value of green building construction starts 

was up 50% from 2008 to 2010—from $42 billion to $71 billion—

and represents 25% of all new construction activity in 2010. 

According to projections, the green building market size is expected 

to reach $135 billion by 2015.

The report noted “In today’s economy, firms that specialize in 

green or serve this market are seeing a tremendous advantage.” The 

report attributes the rapid expansion to builders’ desire for market 

differentiation, growing public awareness, and an increase in government 

rules (Koch 2010; McGraw-Hill Construction 2011; Bernstein 2011).

Research shows that consumers want energy efficiency and they are 

willing to pay for it:

•	 There continues to be a strong willingness to invest in energyefficient products to help reduce utility costs even though a

troubled housing market has homeowners concerned about 

affordability (American Institute of Architects 2010).

Building America builders ranked highest 

in overall customer satisfaction in 11 of 17 

new home markets and were among the 

top three in all 17 markets surveyed by 

J.D. Power in 2010. 

Building America builders Shea Homes 

and Standard Pacific Homes each took 

highest ranks in three markets and KB 

Homes took highest rank in two markets. 

Building America builders also ranked 

in the top three in all 17 markets in J.D. 

Power’s new-home quality study. Other 

Building America partners that placed 

highly include David Weekley Homes 

(shown here), Del Webb, DR Horton, 

John Wieland, K. Hovnanian, Lennar, 

Pardee Homes, Pulte, Ryan, and Ryland 

(J.D. Power 2010).

ranville

49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67

“In this hypercompetitive market, 

green features have become a 

crucial selling point, since newhomebuyers are seeking to save 

on energy costs, as well as to 

increase the value of their home.” 

Dale Haines, senior director of the real 

estate and construction industries 

practice at J.D. Power and Associates 

(J.D. Power 2010).

CHAPTER 2 / BUILDING AMERICA BEST PRACTICES SERIES

2.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
•	 63% of consumers said they were interested in owning or renting a 

green or energy-efficient home and 67% said that ENERGY STAR 

qualification would have the most impact when comparing two 

homes for purchase (Shelton Group, 2011).

•	 For homeowners in a 2010 study, home energy-efficiency features 

outshone all else. Overall, the energy-efficient features were the 

highest-rated home design elements of the study (Cardis 2011).

•	 87% of homebuyers said a greener, more energy-efficient home 

is a priority in a Better Homes and Gardens Magazine survey 

(Patterson 2010).

•	 94% of builders report that their buyers want more energy-efficient 

new homes; 55% said buyers specifically want ENERGY STAR®

homes (NAHB 2009). 

•	 91% of homebuyers preferred an energy-efficient home with lower 

utility bills to a cheaper home (sales price 2% to 3% lower) without 

the energy-efficient features (Rice 2009). 

•	 Homebuyers are willing to pay on average $6,000 more for their 

new home to save $1,000 annually on energy costs (Rice 2009).

•	 86% of Americans would choose one home over another based on 

its energy efficiency. Yet 78% of the homeowners polled said no one 

talked to them about energy efficiency during the buying process 

(National Building News, April 9, 2007).

•	 90% of new homebuyers are willing to spend more for energy 

efficiency—up to $17,000 more (McGraw Hill 2007).

Competitive Advantage

Urbane Homes, a builder in Louisville, Kentucky, has become 

a leader in high-performance homes in a remarkably short time, 

receiving industry honors for design and construction approaches 

that raise the level of energy efficiency in the area. “Last year we were 

the 14th biggest home builder in Louisville, and now we’re in the top 

10,” said co-founder Abe Gilbert. Gilbert says Urbane Homes sells 

every house they build, and they don’t do any formal advertising.

“We just list the house about two weeks before it’s done so people 

can come and see it. The longest we’ve had a house listed is 3 weeks. 

The last one we sold was on the market for just 2 weeks.”

Urbane Homes’ dollar sales volume has doubled every year since 

they started building, and they’ve already had repeat buyers who 

sold their original Urbane homes at a significant profit. “One family 

has just moved into the third house we’ve built for them,” said 

Gilbert. “When they sold their last home, they got their asking price 

Building America Partners on 

Builder Magazine Top 100 List 2010 

Ranking Building America Partner

1 D.R. Horton

2 Pulte

3 Lennar

4 NVR

5 KB Home

6 Habitat for Humanity Int’l

7 K. Hovnanian

8 The Ryland Group

9 Beazer Homes USA

10 Meritage Homes Corp.

12 Standard Pacific Corp

14 Taylor Morrison Homes 

17 Weyerhaeuser Real Estate Co

18 Shea Homes

19 David Weekley Homes

32 William Lyon Homes

40 Mattamy U.S. Group 

63 Heartland Homes

65 John Wieland Homes 

and Neighborhoods

77 ICI Homes

90 Ideal Homes

All ten of the nation’s ten largest builders 

are Building America partners, having one 

or more divisions who have participated in 

Building America research projects. Twentyone of Building America’s 350 plus builder 

partners made Builder Magazine’s Builder 

100 list of the top 100 U.S. builders of 2010 

(based on home sale closings). 

“The downturn of the housing 

market—along with intensified 

competition for a very limited pool 

of homebuyers—has reinforced the 

importance of customer focus for 

new-home builders. Many builders 

that were unable to maintain this 

focus consistently have had to exit 

the marketplace.” 

Dale Haines, senior director of the real 

estate and construction industries practice 

at J.D. Power and Associates.

(J.D. Power 2010) 

2.3

CHAPTER 2. THE BUSINESS CASE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 2.3
in four days and that was $40,000 more than they bought it for four 

years ago. Another one of our homeowners just had a job relocation 

to another state. He put the house we built for him up for sale and 

sold it in one day, for $30,000 more than he bought it for a year ago.”

One secret to their success may be affordability. Urbane Homes 

worked with the National Association of Home Builders Research 

Center (NAHBRC), a Building America research partner, to develop 

homes that were energy efficient and affordable. “We set out to prove 

that we could build a really good house for an affordable price, and 

we built that first house for $36 per square foot,” said Gilbert. A 

typical home in Louisville costs between $55 and $85 per square foot 

to build, not including the lot. Urbane’s 1,500 to 3,000 ft2

 homes go 

for $150,000 to $450,000 and have HERS scores of 57 to 62. 

Insight Homes of Seaford, Delaware, also committed to keeping 

its homes comparable to other market rate homes while increasing 

its energy efficiency. Insight has chosen to market its homes 

exclusively on the basis of energy efficiency. Growing sales figures 

seem to indicate that combining energy efficiency with affordability 

is one way to beat a down market. In 2008 and 2009, Insight had 

38 closings on homes at Deep Creek as well as other communities 

in Sussex County, Delaware. Insight sold 54 homes in 2010 and 

expects to finish building and selling 70 homes by the end of 2011. 

Insight Homes also has a long backlog of orders for new houses that 

promises to keep its sales numbers growing.

Research in other parts of the country also shows that energyefficient homes sell for more and sell faster. Homes that were 

green certified sold for up to 30% more on average based on May 

2010-April 2011 multiple listing sales data for the Portland, Oregon, 

metropolitan area, according to a study by Earth Advantage 

Institute. Certified homes in Atlanta spent an average of 97 days 

on the market compared to 123 days for traditionally built homes, 

according to data in the Atlanta Green Home Sales Report, as 

reported in Builder Magazine (Kittower 2011).

Cost-Neutral Energy Savings

Building America case studies prove that energy-efficient 

construction does not have to cost more for homebuyers. Tradeoffs 

in building material choices, streamlining of processes, and tax 

incentives and rebates can minimize cost increases for builders.

Building America builders have experienced upfront cost savings in 

numerous ways that balance out against the increased costs of some 

energy-efficiency measures. For example, they have used advanced 

framing techniques, which cut down on lumber costs; designed 

How homeowners would 

spend an extra $5,000 

on their new homes 

(Figure source: NAHBRC 2007) 

 26% would pay for energy improvements

 22% for new countertops 

 23% for other

 17% for upgraded flooring

 6% for upgraded appliances

 5% for upgraded bathroom features

 1% for new siding

Insight Homes closed on 70 homes in 

Sussex County, Delaware, by third quarter 

2011, almost double its closings in 2009. 

The company, which markets its homes 

exclusively on their energy efficiency, has 

a long backlog of orders that promises to 

keep its sales numbers growing.

CHAPTER 2 / BUILDING AMERICA BEST PRACTICES SERIES

2.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
on a 2-foot grid to reduce materials cost and waste; downsized 

HVAC equipment through better insulation and air sealing of the 

building envelope and right sizing of equipment; and substituted 

rigid foam for structural panel sheathing for better performance at 

neutral cost. They’ve cut labor costs by spray foaming rather than 

individually caulking rim joists, by shortening and simplifying duct 

runs, and by moving ducts out of awkward crawlspaces and attics 

into conditioned space. Builders have reduced construction time and 

money by prefabricating duct components on the ground and by 

factory-building frame wall components or using structural insulated 

panels (SIPs). They’ve streamlined processes, realized savings from 

vendors, reduced or eliminated callbacks, and cut back on costly 

schedule overruns through good upfront planning with integrated 

management techniques, ongoing training of subcontractors, and 

interim and final inspections and commissioning.

Case Studies Prove Homebuyers Profit

In 2007 through 2010, Building America researchers worked with 

five builders in the mixed-humid climate to build 62 homes that 

met or exceeded 40% energy savings. (Four of these builders are 

showcased in case studies at the back of this guide.) In each of those 

projects, homeowners’ utility bill savings yielded a net profit each 

year, after subtracting increased mortgage costs. 

Researchers from Building America research teams modeled one 

house plan from each builder using EnergyGauge and BEopt software. 

Table 2.1 shows the energy cost savings calculated for each builder’s 

home, the incremental increase in the annual mortgage to cover the 

costs of the energy-efficiency features versus the cost of a mortgage 

for a typical house, and the net annual cash flow to the homebuyer. 

In every case the homebuyer came out ahead, with net gains ranging 

from $263 to $1,541 per year. These examples show how homebuyers 

can realize a positive return from energy-efficiency improvements, no 

matter how the stocks and bonds markets are doing.

Table 2.2 details costs associated with one builder’s choices in 

energy-efficient features. The builder, Insight Homes in Seaford, 

Delaware, spent $7,660 per home to add energy-efficiency measures 

to achieve energy savings of 50% over the Building America 

benchmark. These measures included increasing the ceiling and 

wall insulation, switching to a tankless water heater, upgrading 

the furnace, air conditioner, windows, lighting and appliances and 

increasing air sealing. When these costs are added to the sale price 

of the home (at a 10% markup) and incorporated into a 30-year 

mortgage at 7% interest, it adds $612 per year to the homeowner’s 

mortgage but calculated utility savings are $1,405 annually per home, 

so the homeowner actually nets a profit of $793 per year. 

Energy-Saving Features Are “In” 

Energy-saving features are “in” according 

to builders polled by the National 

Association of Home Builders at the 2010 

NAHB International Builders Show in Las 

Vegas in January 2010. When builders were 

given a list of 40 features and asked which 

ones they were likely to include in new 

homes, five of their top 10 choices 

were energy-related. 

“Builders will focus heavily on energy-saving 

features (low-e windows, programmable 

thermostats, energy-efficient appliances 

and lighting, an insulated front door, and 

lower ceilings on the first floor). Things we 

thought were consumer necessities—such 

as granite countertops in the kitchen or 

home offices—are not on the list,” Rose 

Quint, assistant vice president for NAHB’s 

Survey Research Economics and Housing 

Policy Group, told media at the 2010 NAHB 

International Builders Show (RREA 2010).

“The longer they [builders] wait 

to build energy-efficient houses, 

the further behind they are going 

to be. It’s definitely what buyers 

are looking for. It is better to be 

pro-active than reactive.” 

Rich Coyle, vice president for building 

science at DR Horton’s Sacramento division

2.5

CHAPTER 2. THE BUSINESS CASE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 2.5
Table 2.1. Mixed-Humid Climate Case Study Costs and Savings

Every Building America project yielded net annual gains for homeowners, after deducting increased mortgage costs from annual 

utility bill savings.

Builder

Added Builder 

Cost for Energy 

Improvements

Annual Mortgage 

Payment Increase for 

Energy Efficiency

Annual Utility 

Bill Savings vs. 

Benchmark

Net Annual 

Cash Flow to 

Homeowner

Total Energy 

Savings

Insight Homes $7,660 $612 $1,405 $793 50%

Pine Mountain Builders $11,486 $917 $1,180 $263 41%

Tindall Homes $21,290 $1,699 $3,240 $1,541 49%

Urbane Homes $1,612 $151 $713 $562 44%

In every case study, the energy-efficiency improvements are actually money makers for the homeowners.

Utility bill savings relative to the Building America benchmark were calculated using EnergyGauge and BEopt 0.8.6 software. Cost 

increases are based on builder estimates and additional data sources such as RS Means, DEER, supplier cost bids, etc. A 10% markup 

is assumed and the cost is converted into an annuity assuming a 7% loan over 30 years. Inflation, incentives, and rebates are not 

considered. The Building America benchmark is a home built to the 1993 Model Energy Code.

Table 2.2. How Much Does it Cost to Reach 40% Energy Savings? 

One Example in the Mixed-Humid Climate

The example shown here is for a typical 2,140 ft2, 1-story, 3-bedroom, 2.5-bath, “Jerry” plan home built by Insight Homes, in Seaford, 

Delaware. Estimated costs for energy-efficiency measures are listed in the table below. As shown, when increased mortgage costs are 

balanced against utility savings, the homeowner comes out ahead $793 each year.

Energy-Efficiency Feature Added Cost, per Home, Over 

Builder’s Conventional Practice

Increase walls insulation to R-22 dense-packed blown fiberglass $2,500

Increase air sealing $500

Upgrade windows $500

Upgrade furnace $1,000

Upgrade Air conditioner $200

Improve duct insulation and sealing $200

Add timer-controlled bath fans $300

Add tankless water heater $1,000

Upgrade to all CFL lighting $100

Add ENERGY STAR appliances $700

3rd party inspections $660

Total Added Cost $7,660

Annual mortgage payment increase (when incorporated into a 30-year loan at 7% interest) $612

Annual utility bill savings (Compared to Building America benchmark) $1,405

Net Annual Cash Flow to Homeowner $793

Conclusion: These energy-efficiency improvements are actually money makers for the owner of this home.

Cost estimates were provided by the builder. A 10% markup is assumed. Incentives and rebates are not considered.

CHAPTER 2 / BUILDING AMERICA BEST PRACTICES SERIES

2.6 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Federal, State, and Local Incentives and Tax Credits

Incentives can help offset costs as builders transition to more energyefficient construction materials. A wide range of incentives and tax 

credit opportunities are available at the federal, state, and local level. 

In addition to financial incentives for energy-efficient homes, some 

local governments offer streamlined permitting processes for green 

and energy-efficient projects. 

For information on what is available to you, visit the Database 

of State Incentives for Renewables and Efficiency (DSIRE), at 

www.dsireusa.org. DSIRE is a comprehensive source of information 

on state, local, utility, and federal incentives, tax credits, and policies 

that promote renewable energy and energy efficiency. Established 

in 1995 and funded by the U.S. Department of Energy, DSIRE is 

an ongoing project of the North Carolina Solar Center and the 

Interstate Renewable Energy Council.

Although the $2,000 Federal tax credit for building a new energyefficient home expired on December 1, 2009, other tax credits 

for specific measures still exist. For new home construction, until 

December 31, 2016, a tax credit covering 30% of the cost (with 

no upper limit) is available for geothermal heat pumps, small 

residential wind turbines, and solar energy systems. Also available 

until December 31, 2016, is a 30% tax credit with up to $500 per 

0.5 kW of power capacity for residential fuel cells and micro-turbine 

systems. See www.energystar.gov/index.cfm?c=tax_credits.tx_index.

This site provides easy-to-follow information about eligibility and 

applying for these tax credits.

The ENERGY STAR “Special Offer/Rebate Finder” website below 

enables a user to enter a zip code to receive accurate information 

about rebates and sales tax exemptions or credits for qualified 

products. These include most major appliances, residential ventilation 

fans, heating and cooling equipment, insulation, roof products, 

windows, doors, lighting, water heaters, and office equipment. See 

www.energystar.gov/index.cfm?fuseaction=rebate.rebate_locator.

ENERGY STAR has more information for builders interested in 

qualifying homes through ENERGY STAR’s new home program at 

www.energystar.gov/index.cfm?c=bldrs_lenders_raters.pt_bldr.

Builders can check ENERGY STAR’s New Homes Partner Locator 

page for state contacts for locally administered builder incentives 

for new ENERGY STAR homes at www.energystar.gov/index.

cfm?fuseaction=new_homes_partners.locator.

“Over their lifetimes, our houses 

will save more in energy costs 

than the purchase price.”

Mark Bergman, owner, Tindall Homes, 

Columbus, New Jersey

Tindall Homes was able to cut energy 

use 50% compared to the Building 

America benchmark home, saving 

homeowners a calculated $3,240 per 

year on their utility bills.

2.7

CHAPTER 2. THE BUSINESS CASE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 2.7
For More Information on the Business Side of Building 

2009 IECC. 2009. International Energy Conservation Code, International Code Council (ICC), 

Washington, D.C. www.iccsafe.org/Store/Pages

2009 IRC. 2009. International Residential Code - One and Two-Family Dwellings, 

International Code Council (ICC), Washington, D.C. www.iccsafe.org/Store/Pages

American Institute of Architects. 2010. Home Design Trends Survey. Accessed May 19, 

2011 at www.aia.org/practicing/AIA B085952. (Blog description at www.designcrits.

com/2010/10/05/48/) 

Bernstein, Harvey M. 2011. “The Green Outlook 2011: Green Trends Driving Growth through 

2015.” Outlook 2011 Executive Conference. Prepared by McGraw Hill Construction, Accessed 

May 18, 2011 at www.buildingtrades.org/getattachment/Newsroom/Latest-News/IndustryHeadlines/CONSTRUCTION-INDUSTRY-%E2%80%93-OUTLOOK-AND-PROJECTIONS-FO/

Bernstein,Harvey.pdf.aspx

Builders Magazine. 2010. “Builder 100.” www.builderonline.com

Calvert Investments. 2010. 2010 Report: A Green Recovery for America’s Homebuilders? An 

updated report. December 2010, www.calvert.com/sr-greener-pastures.html.

Cardis, Paul. 2011. “Welcome to Home Building 2011: What’s Different?” Avid Ratings and 

Bassenian | Lagoni PowerPoint presentation at the 2011 International Builders’ Show, 

Orlando. Accessed May 19, 2011 at www.avidbuilder.com/sites/default/files/private/2011_

design_drivers_ibs__presentation.pdf. 

Caufield, John. 2010. “Hard Landing, The housing market may have finally hit bottom in 

2009,” Builder Online, posted May 4, 2010, www.builderonline.com/sales/hard-landing.aspx

Dakin, Willard, David Springer, and Bill Kelly. 2008. “Case Study: The Effectiveness of Zero 

Energy Home Strategies in the Marketplace.” In Proceedings of the 2008 ACEEE Summer 

Study on Energy Efficiency in Buildings, American Council for an Energy-Efficient Economy, 

Washington D.C.

DOE. 2010. “Builders Challenge Video Transcript.” U.S. Department of Energy, Builders 

Challenge, www.eere.energy.gov/buildings/challenge/bc_video_transcript_021210.html.

Energy Savings Association. 2011. “Survey Reveals Energy Efficiency Desire and Financial 

Challenges.” May 11, 2011, www.the-esa.org/news/-/survey-reveals-energy-efficiency-desireand-financial-challenges

Halford, Tom. 2011. “Survey: How Consumers and Builders Feel About Green Homes.” 

TriplePundit. Accessed May 20, 2011 at http://www.triplepundit.com/2011/02/surveyconsumers-builders-feel-about-green-homes/. 

James, George. 2010. “Building America and Builders Challenge, Recognizing Energy 

Leadership in Homebuilding: Building America Research for New and Existing Homes,” 

Presented November 2, 2010, U.S. Department of Energy, http://apps1.eere.energy.gov/

buildings/publications/pdfs/building_america/rpm2010_welcome_intro.pdf. 

J.D. Power and Associates. 2010. “Satisfaction with New-Home Builders and New-Home 

Quality Reach Historic Highs, as Home Builders Respond to Tough Market Conditions by 

Improving Products and Service,” press release September 15, 2010, http://businesscenter.

jdpower.com/news/pressrelease.aspx?ID=2010177

Kittower, Diane. 2011. “Green Homes Sell for More, Studies Show,” Builder Magazine, August 1, 

2011, www.builderonline.com/green-building/green-homes-sell-for-more-studies-show.aspx

Koch, Wendy. 2011. “Report: Green building market booms despite economy.” USA Today, 

November 17, 2010, http://content.usatoday.com/communities/greenhouse/post/2010/11/

report-green-building-surges/1 

When Abe Gilbert and Zane Underwood 

founded Urbane Homes in 2007, they knew 

their survival depended on building better, 

and more affordable houses than any other 

builder in the Louisville area.

They worked with DOE’s Building America 

program, to make their houses not just 

affordable but very energy efficient, 

achieving HERS scores of 57 to 62.

CHAPTER 2 / BUILDING AMERICA BEST PRACTICES SERIES

2.8 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
In a 2010 study of 16,400 new homebuyers, 

market research organization J.D. Power 

found that new-home builders are 

increasingly using green and energy 

efficiency features as a selling point—65% 

of new home builders identified the green 

features of their homes to homebuyers in 

2010, up from 48% in 2009, and 61% of new 

homebuyers perceived their new home as 

environmentally friendly, compared with 

only 31% in 2009. 

Maynard, Nigel F. 2009. “New Survey Finds Energy, not Water, Drives Appliance Purchases.” 

Builder Magazine, March 27, 2009. www.builderonline.com/appliances/survey-finds-energydrives-appliance-purchases.aspx

McGraw Hill Construction. 2011. Green Outlook 2011: Green Trends Driving Growth.

http://construction.com/AboutUs/2010/1112pr.asp.

NAHB. 2009. “Baby Boomers Want Convenience and Energy Efficiency in New Homes 

According to New Survey,” news release September 15, 2009, National Association of Home 

Builders, www.nahb.org/news_details.aspx?sectionID=1196&newsID=9696/

NAHB. 2007. “Builders Need to Make Energy Efficiency a Selling Point.” Energy Pulse 

Survey by Shelton Group, reported in Nation’s Building News Online, April 9, 2007, National 

Association of Home Builders, www.nbnnews.com/NBN/issues/2007-04-09/Front+Page/

index.html

NAHB. 2007. “In a Down Housing Market, Green Demand Exceeds Supply.” Nation’s Building 

News Online, April 9, 2007, National Association of Home Builders, www.nbnnews.com/

NBN/issues/2007-04-16/Front+Page/index.html

NAHB. 2010. Annual Housing Starts (1978-2010). National Association of Home Builders. 

Accessed May 18, 2011 at www.nahb.org/generic.aspx?sectionid=819&genericcontentid=554

&channelID=311

NAHB. 2011. Builders Challenge Participants Paving the Way to More Affordable Energy 

Efficiency. National Association of Home Builders. Accessed May 18, 2011 at 

www.nahb.org/news_details.aspx?newsID=11944.

NAHBRC. 2007. Building America Challenge Survey of Builders and Consumers. Proprietary 

survey commissioned by DOE and conducted by the NAHBRC as part of the Annual 

Consumer Practices Survey. National Association of Home Builders Research Center, 

Upper Marlboro, MD.

Patterson, Jean. 2010. “Buyers seek smarter and smaller homes, survey says,” The Seattle 

Times, February 8, 2010, http://seattletimes.nwsource.com/html/homegarden/2011019068_

cozyhomes09.html

Quint, Rose. 2011. “The New Home in 2015.” Newsrelease January 13, 2011, National 

Association of Home Builders, www.nahb.com/fileUpload_details.aspx?contentTypeID=3&co

ntentID=153664&subContentID=334586&channelID=311

RREA. 2010. “What do homebuyers want in 2010?” January 25, 2010, Register Real Estate 

Advisors, http://rrea.com/news/what-do-homebuyers-want-in-2010-builders-hope-they-know/

Rice, Alison. 2009. “Consumers Rethink Home-Buying Priorities,” Builder 2009. 

January 22, 2009. www.builderonline.com/housing-trends/consumers-rethink-homebuying-priorities.aspx

Shelton Group. 2011. “The Energy Efficient Consumer: The Latest Insights on Consumers and 

their Views on Energy, Conservation and You.” Presentation by the Shelton Group, accessed 

May 19, 2011 at http://www.tppa.com/events/2011/shelton.pdf. 

Thompson, Boyce. 2011. “Future of Housing Burning Issues: As the housing industry 

recovers, can we expect more of the same, or a whole new dynamic?” Builder, January 3, 

2011, www.builderonline.com/housing-trends/burning-issues.aspx?printerfriendly=true.

“If all builders built to save 50% 

on energy use, we could make 

a big difference. We all want 

to make money, but at some 

point, as a society, we have to 

evaluate what we are doing. We 

take seriously our responsibility 

to the surrounding community, 

to the environment, and most 

importantly to our buyers.”

Mark Bergman, Owner, Tindall Homes, 

Columbus, New Jersey

2.9

CHAPTER 2. THE BUSINESS CASE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 2.9
Codes as Drivers

New building energy codes are now a driving force in energy-efficient 

construction. 

The International Energy Conservation Code

The 2009 International Energy Conservation Code (2009 IECC) 

was published in December 2008 and has gotten a boost in adoption 

from the American Recovery and Reinvestment Act (ARRA) 

of 2009. States seeking funding for building programs through 

the Act must show that they have adopted building energy codes 

for residential buildings that meet or exceed the 2009 IECC. The 

provisions of the 2012 IECC were finalized at the Final Action 

Hearings in November 2010 and published in June 2011. For the 

current status of state code adoption, see the DOE Building Energy 

Codes website, www.energycodes.gov. IECC 2009 code requirements 

are shown throughout this document in green ink. Tables comparing 

the 2009 and 2012 IECC requirements for various insulation and air 

sealing requirements are provided in Chapter 8. 

Major changes from the 2009 IECC to the 2012 IECC include 

the following:

•	 75% high-efficacy lighting

•	 Energy provisions (Chapter 11) removed from 2012 IRC; 

reference to 2012 IECC added

•	 New mandatory whole-house pressure test (blower door) with 

stringent required leakage rates

– Zones 1-2: ≤ 5 ACH @50 Pa

– Zones 3-8: ≤ 3 ACH @50 Pa

•	 Domestic hot water piping must be either

– Insulated to R3, or

– Short and skinny (i.e., exempted lengths depend on diameter)

•	 Duct leakage rates lowered

– Eliminated “leakage to outdoors” option

– Changed from 12 to 4 cfm/100 ft2 conditioned floor area 

(after construction)

– Changed from 6 to 4 cfm/100 ft2 conditioned floor area 

(at rough-in)

•	 Climate-specific insulation R-value upgrades for ceiling, wall, 

basement, and crawlspace walls (see tables in Chapter 8)

•	 Climate-specific window U-factor/SHGC increases 

(see table in Chapter 8).

“Everyone needs to understand 

that the difference between the 

way we have been building in the 

past and the way we have to build 

now is night and day. Everyone 

complains about what a pain the 

change in codes is, but there is 

no getting around this. This is 

the way of the future. I think we 

have to start being smarter 

about how we build.”

Todd Winnor, project manager, 

S&A Homes, Pittsburgh

CHAPTER 2 / BUILDING AMERICA BEST PRACTICES SERIES

2.10 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
State Energy Codes

There are 22 states that are wholly or partially in the mixed-humid 

Building America climate zone (which corresponds to IECC climate 

zones 3 (above the “warm, humid” line) and 4 moist; see maps in 

Chapter 5.) The status of residential energy code adoption in each 

state (as of September 2011) is summarized in the map below. Of the 

22 states, eight states have implemented the 2009 IECC, two states 

(Texas and North Carolina) have adopted but the code has not gone 

into effect yet. Table 2.3 below provides details on each state’s energy 

code adoption status. (Also see www.energycodes.gov/states for up-todate state information on energy code adoption). 

Status of Residential Energy Code Adoption 

(as of September 2011)

For More Information on Codes

IECC. 2012. 2012 International Energy Conservation 

Code, International Code Council (ICC), 

Washington, DC. www.iccsafe.org/Store/Pages

2009 IECC. 2009 International Energy 

Conservation Code, International Code 

Council (ICC), Washington, DC. 

www.iccsafe.org/Store/Pages

2009 IRC. 2009 International Residential Code - 

One and Two-Family Dwellings, International Code 

Council (ICC), Washington, DC. 

ww.iccsafe.org/Store/Pages

Building Energy Codes Program. U.S. Department 

of Energy Office of Energy Efficiency and 

Renewable Energy, www.energycodes.gov

2012 – Early Adopters

The provisions of the 2012 IECC were published in June 2011, 

but several Building America builders are already exceeding 

them. Building America builders highlighted in this guide 

are already meeting several of the 2012 requirements. 

Urbane Homes of Louisville, Kentucky, exceeds 2012 IECC 

wall and attic insulation and lighting requirements. Urbane’s 

estimated improvements cost $1,600 over the Building 

America benchmark or $129 per year when included in a 30-

year mortgage at 7% interest. The energy savings would give 

the homeowner $713/year in reduced energy costs for a net 

cash flow to the homeowner of $584 per year.

Features 2012 IECC/CZ 3&4 Urbane Homes

Walls R-20/R-13+R-5 R-19 + R-5 insulated 

sheathing

Attic CZ-3 R-38

CZ-4 R-49 R-50

Duct Leakage 4 cfm per 100 ft2 Ducts in 

conditioned space

Lighting 75% high-efficacy 

fixtures 100% CFLs

IECC 2009, 

equivalent or 

more stringent

IECC 2006, 

equivalent or 

more stringent

IECC 2003, 

equivalent or 

less stringent

No Statewide Code

* Adoption by county/

jurisdiction above 

state-mandated 

minimum

American Samoa

Guam

N. Mariana Islands

Puerto Rico

U.S. Virgin Islands

IL IN

MI

OH

PA

NY

VTNH

ME*

MA

CT RI

NJ

DE

DC

MD

VA WV

KY

TN*

MS*

LA

AL*

SC

NC

FL

GA

IA

*MO

MT

WA

OR

NV

ID

UT

HI*

AK

CA CO*

WY*

SD*

ND*

NE

KS*

OK* AZ* NM AR

TX

WI

MN

2.11

CHAPTER 2. THE BUSINESS CASE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 2.11
Table 2.3. Status of Energy Code Adoption in U.S. Mixed-Humid Climate States (as of September 2011)

States Statewide Residential 

Code

Adoption by Local County/

Jurisdiction Notes

Alabama None Voluntary 2006 IECC with amendments 

contingent upon local adoption

In the process of adopting the 2009 IECC 

with amendments statewide

Arkansas 2003 IECC 

with amendments

Voluntary

Delaware 2009 IECC Mandatory

Georgia 2009 IECC 

with amendments

Mandatory

Illinois 2009 IECC Mandatory In the process of adopting the 2012 IECC

Indiana Indiana Energy 

Conservation Code 

which is based on the 

1992 Model Energy 

Code with amendments

In the process of adopting 2009 IECC with 

amendments

Kansas None Voluntary adoption by jurisdictions Homebuilders or realtors must disclose 

information about the home energy 

performance parameters on the Kansas 

Energy Efficiency Disclosure form and 

provide it to potential buyers.

Kentucky 2006 IECC/IRC

Louisiana 2006 IECC/IRC Mandatory 2009 IRC with Chapter 11 (Energy Efficiency) 

to remain as the 2006 IRC provisions became 

effective Jan. 1, 2011

Maryland 2009 IECC Mandatory

Mississippi None Voluntary adoption by jurisdictions

Missouri None Voluntary adoption by jurisdictions

New Jersey 2009 IECC with 

minor amendments

Mandatory

North Carolina 2009 IECC with 

amendments

Mandatory Adopted 2009 IECC with amendments, 

effective Jan 2012

Ohio 2009 IECC Mandatory

Oklahoma None Voluntary adoption by jurisdictions

Pennsylvania 2009 IECC Voluntary adoption by jurisdictions

South Carolina 2006 IECC Mandatory

Tennessee 2006 IECC Mandatory

Texas 2009 IECC Mandatory 2009 IECC effective January 1, 2012. Many 

jurisdictions have already adopted the most 

recent codes. 

Virginia 2009 IECC/IRC Mandatory

West Virginia 2003 IRC Mandatory

CHAPTER 2 / BUILDING AMERICA BEST PRACTICES SERIES

2.12 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
For builders who want to build high-performance homes and achieve 

a healthy bottom line, sound business systems are a critical part of the 

picture. This chapter introduces the following four practices to aid in 

construction planning and management: 

•	 quality management 

•	 integrated design 

•	 value engineering 

•	 prototype development. 

Each of these practices has value on its own, but they work best 

when applied as part of an overall management system suited to 

an individual business.

Quality Management 

Quality management is a systems approach to achieving maximum 

customer satisfaction at the lowest overall cost to your organization 

while continuing to improve your building process. It encompasses 

quality of design and quality of process. A quality management 

system establishes the structure, responsibilities, and procedures 

required to achieve your company’s goals. 

Four terms are often used when describing quality programs: 

quality planning, quality control, quality assurance, and quality 

improvement. These terms are described below, based on the 

definitions derived in part from the American Society for Quality 

(www.asq.org).

Chapter 3.

Business 

Management Tools

Builders learn quality management 

concepts at a workshop, conducted 

by Building America research team 

lead IBACOS.

Principles of Quality Management

•	 Customer focus to understand and 

anticipate needs and requirements, 

and meet expectations

•	 Leadership in unity of purpose and 

direction in achieving quality objectives

•	 Involvement of people at all levels to use 

their input and abilities to best advantage

•	 Process approach to managing activities 

and related resources

•	 Systems management approach 

to identifying, understanding, and 

managing interrelated processes

•	 Continual improvement of overall 

performance

•	 Factual approach to decision-making 

based on data analysis and information

•	 Mutually beneficial supplier relationships 

based on interdependent abilities to 

add value.

(ASQ 2008) 

CHAPTER TOPICS

3.1 Quality Management

3.10 Integrated Design

3.15 Value Engineering

3.16 Managing Innovation 

with Prototypes

3.1

CHAPTER 3. BUSINESS MANAGEMENT TOOLS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 3.1
•	 QUALITY PLANNING: the up-front gathering of resources to 

achieve quality goals and objectives and develop clear strategies 

and actions for achieving them. Quality planning considers 

people, processes, and products as interdependent factors in the 

management of quality. It defines the methods for achieving 

the targeted end results and sets a timetable for completing the 

associated processes (collections of activities structured to produce 

well-defined quality outputs).

Planning for quality ensures that you build homes as designed 

to achieve targeted results with optimal energy savings. This 

outcome requires that you fully understand your customer’s 

needs and expectations before proceeding with building design 

and development. Your planning process then should define the 

steps to be taken to ensure the home building effort meets quality 

standards and customer energy-saving expectations on schedule 

from start to finish.

•	 QUALITY CONTROL: the operational activities used to fulfill 

requirements for quality (to produce a home that achieves the 

desired quality for the price). These activities include evaluations, 

such as statistical studies to evaluate product variation, expected 

failure rates, and corrective actions.

Planning for quality control begins with defining the customer’s 

standard for design quality, then planning how to achieve it using 

the best practices, equipment, materials, personnel, and associated 

training. Builders should focus on constructing each building right 

the first time, evaluating and correcting any quality deficiencies as 

you go. Quality systems and a quality culture provide for longterm quality control (Misronet 2011; also see the Building America 

Quality Control Checklist and associated information sheets 

[Building Science Corporation 2008, 2011]).

•	 QUALITY ASSURANCE: the mechanism for ensuring that 

the construction process takes place within the framework of 

your quality management system. It involves the planned and 

systematic activities that provide confidence that a product fulfills 

the requirements for quality to achieve the targeted performance 

levels for construction and ultimate customer satisfaction. 

Quality assurance practices may include tests, such as blower door 

tests; inspections; the use of checklists; and systematic training. 

As recommended by the Building Science Corporation for new 

residential construction, quality assurance includes the following 

seven steps:

New Tradition Homes incorporates these 

elements in its quality management 

program: an in-house building science 

team, a corporate commitment to energy 

efficiency, ongoing training of staff, 

participation in federal and regional 

energy-efficiency programs, a dedicated air 

sealing contractor, third-party performance 

testing, in-house marketing research, and 

an ongoing, interactive relationship with its 

heating, ventilation, and air conditioning 

(HVAC) contractor. 

“While a quality home need not 

necessarily be a high-performance 

home, any high-performance 

home MUST be a quality home. 

The quality management 

approach is an essential element 

of the Building America approach 

to homebuilding because it is 

the main vehicle for moving from 

science to implementation.” 

Building Industry Research Alliance, 

a Building America research team lead

CHAPTER 3 / BUILDING AMERICA BEST PRACTICES SERIES

3.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
1. Review past construction and risk assessment to provide 

a baseline for future decision-making and identify specific 

performance problems.

2. Set performance goals to guide decisions about changes in 

technology and building practices.

3. Incorporate changes to drawings, specifications, contracts, and 

trade scopes of work based on thorough discussion, verification, 

and feedback.

4. Provide training for site supervision and trades as a vital part 

of implementing high performance measures that affect the 

whole house.

5. Conduct onsite inspections, verification, and trouble-shooting 

to confirm quality and verify whole-house characteristics.

6. Complete commissioning of mechanical systems and other 

equipment to ensure their proper operation and maintenance.

7. Conduct post-construction evaluation to ensure that goals are 

achieved. (This is a fundamental part of continuous quality 

improvement and achieving customer satisfaction).

For further reading and other quality assurance resources, 

see the Quality Assurance Roadmap for High Performance 

Residential Buildings (Lstiburek and Pettit 2008). 

• QUALITY IMPROVEMENT: a formal approach to analyzing 

performance and systematic efforts to improve it and the 

reliability of achieving a targeted outcome. A related term—total 

quality management—refers to all members of an organization 

participating in improving processes, products, services, and the 

culture in which they work. The use of quality improvement 

methods and techniques, such as process mapping, quality circles, 

Six Sigma, DMAIC (define, measure, analyze, improve, control) 

and Kaizen—drives ongoing efforts to improve building process, 

product, and people-based performance in pursuit of optimum 

quality and error-free performance (Vitalo 2011).

Quality improvement may focus on improving performance related 

to your product comfort and durability, work-related injuries, 

energy efficiency, savings, and customer satisfaction.

Many companies formalize their quality management processes 

and practices. Other companies simply incorporate tools into their 

business practices that help to improve quality. Some companies 

choose to become certified under third-party quality assurance 

programs. The important point is to plan for quality. 

Strategic, Tactical, and 

Operational Layering of 

Quality Management

Strategic attention to quality 

management via self-assessment 

relative to the National Housing Quality 

Award performance criteria helps 

identify strengths, gaps, and target 

opportunities for improvements that 

benefit customers, employees, owners, 

suppliers, and the business.

Applying tactical standards, including 

builder certification, ensures the 

quality of processes and products 

in accordance with agreed-upon 

specifications to meet established 

standards for high-performance homes.

Building upon Building America’s 

specifications for high-performance 

homes, the use of operational tools and 

techniques ensures customer-focused 

planning to achieve targeted quality 

performance and deliverables.

(Diagram from NAHBRC 2010; 

also see Leonard 2011)

Building America, High Performing Homes

• DMAIC (Six SIgma)

• Flowcharting • Scopes of Work

• Action Plans • Kaizen

QMS

Builder

Certification

NHQA

Assessment

Models

(High-level) 

Quality Management

Standards

(Framework) 

Quality Assurance

Tools

(Detail) 

Quality Control

Specs

Strategic

Tactical

Operational

3.3

CHAPTER 3. BUSINESS MANAGEMENT TOOLS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 3.3
Building America Quality Management Guidelines

Building America’s Integrated Building and Construction Solutions 

(IBACOS) research team has developed comprehensive quality 

management guidelines for builders. The recommendations encompass 

all facets of the builder’s organization including leadership, strategic 

planning, customer satisfaction, performance management, jobsite 

responsibilities, safety, workforce development, quality construction 

processes, and trade contractor and supplier partnerships. This 

operations evaluation is based on the National Association of 

Homebuilders Research Center’s National Housing Quality Program. 

The recommendations can be found in Appendix D of the report, 

Achieving 30% Whole-House Energy Savings Level in Marine Climates, 

prepared by Building America’s research teams (DOE 2006).

In accordance with these guidelines, Building America recommends 

that a quality management approach include the following four 

components: 

•	 TRAINING AND EDUCATION – for builders, trades, and 

sales staff (including participating in certification programs); 

see Chapter 12 for more information about training.

•	 OPERATIONAL EVALUATION – described above and by DOE (2006).

•	 PERFORMANCE-BASED STANDARDS – described throughout 

this guide; examples include DOE’s Builders Challenge and EPA’s 

Thermal Enclosure Checklist.

•	 VERIFICATION/COMMISSIONING/FEEDBACK – 

testing and inspections; see Chapter 11 for more details.

The Costs of Quality Management

Understanding the costs of quality and its potential impact is 

fundamental to establishing the best practices and processes for use 

throughout a project using quality management’s customer-focused 

systems approach. Quality is proportional to construction process 

costs, so you need to identify the costs associated with quality to 

support your decisions.

Because the economic costs of quality management to builders 

can affect the economics of energy-efficiency upgrades in a highperformance home, an effective quality management system needs 

to create efficiencies and related savings that are greater than the 

investments in the quality activities required to achieve the savings. 

One Building America goal is for the amortized cost of energy 

To ensure adherence to quality standards, 

Urbane Homes holds pre-construction 

meetings to coordinate trade contractors 

and ensure buy-in from the site 

superintendent. They provide training 

sessions for their subcontractors on the 

use of newer products like exterior rigid 

foam and they have developed a framing 

manual for the special techniques 

they expect their framers to use. All 

of Urbane’s houses meet the Building 

America 40% savings standard and 

are five-star ENERGY STAR certified. 

ENERGY STAR provides third-party 

testing for energy efficiency. 

(Photo source: Urbane Homes)

Related Standards & Procedures

•	 ISO 9000, “Quality Management 

Systems” www.iso.org

•	 2009 International Energy Conservation 

Code, Section 103.2 “Information on 

construction documents,” International 

Code Council (ICC), Washington, DC. 

Available for purchase at 

www.iccsafe.org/Store/Pages 

CHAPTER 3 / BUILDING AMERICA BEST PRACTICES SERIES

3.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
efficiency upgrades for each high-performance home to be less than 

the monthly utility bill savings. To meet this goal, homebuilders must 

measure the cost of quality to derive a more energy-efficient home 

that is cost-effective for a homeowner to buy and operate. 

Quality-related activities that will incur costs fall under prevention, 

appraisal, and failure-correction activities. Make it your goal to 

reduce the overall cost of quality so that most of your costs are 

related to preventing and catching defects rather than correcting 

failures. Tracking the costs and benefits of each helps you determine 

the most cost-effective solution and reduce failures (and associated 

costs), thereby increasing customer satisfaction.

The $124,000 Rule of Construction Defect Claims: 

This figure developed by the American Contractors Insurance Group, Inc., 

represents the costs of delaying the identification and solution of problems 

during the construction process. The initial investment in up-front quality 

planning and ongoing quality management save in the long run in terms of 

production efficiencies, costs, and defining a clear path forward by addressing 

prevention and appraisal needs from project start.

(Copyright ©2009 American Contractors Insurance Group, Inc.)

The final judge of quality is the consumer. If a builder consistently 

meets consumer expectations, the rewards are tremendous. 

Consumer research organization J.D. Power found that truly 

delighted homebuyers (those rating their builders a 10 on a 10-point 

scale) recommend their builder to nearly twice as many people as the 

average new homebuyer (J.D. Power 2008).

Costs of Quality

•	 Prevention costs are related to 

the design, implementation, and 

maintenance of the quality management 

system; quality planning; quality 

assurance; and training. These may 

involve the costs of providing better 

designs, more training to reduce failure 

costs, and more maintenance.

•	 Appraisal costs are related to the 

suppliers’ and customers’ quality-based 

evaluation of purchased materials, 

processes, products, and services 

(inspection and testing).

•	 Failure costs are incurred when the 

results of field work or the products or 

services delivered to the customer fail to 

reach design quality. These may involve 

the costs of callbacks, demolishing and 

rebuilding, production time, or delays to 

other trades.

(U.S. Department of Trade and Industry 2011; 

Misronet 2011)

Impacts of Quality Management

By coupling quality management systems 

with high-performance home building 

techniques, builders are likely to create 

satisfied customers and increased profits. 

Builders who have won the National 

Housing Quality Award (NHQA) have noted 

tremendous impacts from implementing 

quality management systems, as this 

sampling of results indicates: 

•	 Achieved zero defects in 98% of homes 

at closing; net profits increased 9% 

(Grayson Homes, MD) 

•	 Reduced cycle time by 15% 

(Pringle Homes, FL) 

•	 95% of trades list builder as the best 

to work for (Estes Homes, WA) 

•	 33% of homeowner recommendations 

resulted in sale (TS Lewis, AZ). 

(Professional Builder Magazine 2009, 

as cited in NAHBRC 2010) 

$124,000

$12,400

$1,240

$124

$12.40

Construction

Defects

Preparing all the possibilities 

of a construction defect claim 

while adding in attorneys’ fees

Repairing the damage of 

problems or errors caught 

by external customers

Catching and fixing problems 

or errors internally, but after 

they have left the work area

Catching and fixing problems 

or errors in the work area

Catching and fixing problems 

in the Design Stage

Inspection

Stage

Failure

Prevention

Stage

Design

Stage

3.5

CHAPTER 3. BUSINESS MANAGEMENT TOOLS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 3.5
Home builders who use recommended quality management tools 

and techniques and monitor the impacts of quality management to 

assess its effectiveness—identifying problem areas, opportunities, 

savings, and priorities for action—have been shown to achieve 

dramatic improvements in energy and quality performance, 

profitability, and customer satisfaction (NAHBRC 2010). 

Implementing Quality Management

As an accepted cost of doing business, quality management has 

a proven return on investment. Award-winning home builders 

who have successfully introduced quality management into their 

organizations report that the initial up-front investment pays for 

itself in long-term efficiencies and cost savings gained for builders 

and homeowners alike (Leonard and Dickens 2011).

These home builders offer the following steps you may find helpful 

in setting priorities, engaging team members and partners, and 

managing change.

1. Conduct a high-level assessment of your business process to define 

its components, who is responsible for doing what, to what standard 

a process should be completed, and how the success of the business 

process can be measured. Map out current process realities, identify 

gaps to be filled, and align your team members to define a roadmap 

for strategic planning to take you where you want to go.

2. Develop a strategic plan that sets you up for success. Set priorities 

to focus your plan and define improvement initiatives to foster 

achievement of your planned goals and objectives.

3. Create quality improvement teams and develop and communicate 

a clear vision, mission, and goals. Promote ownership by defining 

responsibilities for actions—steps to be taken by whom to 

implement your strategy—and determine how to measure your 

success. Map out individual processes for functional systems and 

for interactions among systems and groups. 

4. Encourage successful change management by creating a sense of 

urgency, using a guiding coalition of building quality management 

advocates, empowering broad-based action, and generating 

short-term wins. 

5. Then consolidate your gains, produce more changes, and anchor 

the new approaches in your operating culture.

6. Use available quality management tools and techniques—such 

as process mapping, DMAIC/Six Sigma, and cause-and-effect 

charts—to define and articulate your processes to integrate 

concepts, team members, and steps so that all participants know 

how to engage in achieving the end goal. 

A certified quality management 

system improves performance 

and makes high-performance 

home building easier

IBACOS studied the impact of a quality 

management system on high-performance 

home builders (Prahl 2010). 

Quality management was found to improve

•	 performance management

(how you develop, manage, measure, 

and improve your key processes)

•	 human resources

(how you support superior work 

performance and ensure organizational 

alignment)

•	 construction quality

(how you provide training and reinforce 

quality standards)

•	 trade relationships

(how you integrate trades to build 

a better company)

•	 business results

(business operations, employee 

satisfaction, and supplier and trade 

satisfaction).

CHAPTER 3 / BUILDING AMERICA BEST PRACTICES SERIES

3.6 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
When implementing quality management, National Housing Quality 

Award (NHQA) winners (Leonard and Dickens 2011) suggest success is 

based on effective leadership practices, strategic planning, performance 

management, customer satisfaction, human resources, construction 

quality, and trade relationships. They recommend the following:

•	 As leaders in quality management, create a deep corporate culture 

based on a clearly articulated vision, operating transparency, open 

communication, and regularly posted performance measures. 

•	 Engage your people by encouraging dialogue and input from all 

functional groups for interdisciplinary collaboration in doing 

things right together. 

•	 Regularly set goals, align teams, and conduct master planning for 

major changes with clear deliverables, deadlines, and ownership. 

•	 Engage ownership of change by inviting employee feedback to 

identify opportunities for improvement and consider centralizing 

operations for operational flexibility derived from shared resources.

•	 Promote customer satisfaction by creating a well-defined 

customer-engagement process. Know what your customer wants 

and remember that high-quality performance and product results 

will sell your business for you.

•	 Hire right; develop your employees through mentoring and 

training; then measure and recognize results.

•	 Define your top 5 or 10 quality metrics and use available methods 

and tools to manage the quality of your building process, 

products, and services.

•	 Maintain positive relationships with the trades by conducting 

regular construction quality and safety meetings, participating on 

trade councils, and measuring and recognizing trade performance. 

Coordinate efforts to focus on excellent strategy performance using 

appropriate tools and practices to achieve desired results.

Once you have defined your standards as the fundamentals of your 

quality platform, regular communication and team work remain key 

to implementing and maintaining successful quality management 

programs. Plan, practice, measure success, take the right qualitypromoting and cost-saving steps to sustain yourselves through tough 

economic times, then look to grow. Merge energy efficiency and 

quality management to combine technology systems with business 

management systems to achieve integrated solutions for sustained 

implementation of energy-efficient homes over the long term.

Quality Management Tools

Use process mapping (a flowcharting 

method) to define individual steps for key 

processes: planning and development, 

product design and purchasing, marketing 

and sales, construction, and customer care.

Use DMAIC/Six Sigma to do the following: 

•	 Define the problem, the voice of the 

customer, and project goals.

•	 Measure key aspects of the current 

process and collect relevant data.

•	 Analyze the data to investigate and 

verify cause-and-effect relationships, 

determine what the relationships are, and 

attempt to ensure that all factors have 

been considered; then seek out the root 

cause of the defect under investigation.

•	 Improve or optimize the current 

process based upon data analysis using 

techniques to create a new, future 

state process; then set up pilot runs to 

establish process capability. 

•	 Control the future state process to 

ensure that any deviations from the 

target are corrected before they result 

in defects, and continuously monitor 

the process. 

Use cause-and-effect (fishbone) charts to 

identify possible causes of problems and 

promote structured brainstorming to help 

avoid tunnel vision.

(Figure from Leonard and Dickens 2011)

Materials

Equipment/

Machines

Method

People

Hotspot

3.7

CHAPTER 3. BUSINESS MANAGEMENT TOOLS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 3.7
For More Information on Quality Management

2009 International Energy Conservation Code. Section 103.2, “Information on Construction 

Documents.” International Code Council (ICC), Washington, D.C. www.iccsafe.org/Store/Pages

ASQ. 2008. ISO 9001:2000 Interpretive Guide for the Design and Construction Project Team. 

American Society for Quality Press, Milwaukee, WI. www.asq.org/quality-press

Builders Challenge. 2008. Builders Challenge Quality Criteria Guide – Version 1.3. 

http://search.nrel.gov/cs.html?url=http%3A//www1.eere.energy.gov/buildings/challenge/

pdfs/bcqc_version_1_3_060408.pdf

Building Science Corporation. 2008. BSC Building America Quality Control Checklist. 

Version 1.0, October 3, 2008. www.buildingscience.com/documents/guides-and-manuals/

gm-building-america-quality-control-checklist/at_download/file

Building Science Corporation. 2011. Resource Appendix (C4). Accessed 2011: 

www.buildingscience.com/documents/information-sheets/gm-building-america-qualitycontrol-checklist-appendix/at_download/file

DOE. 2006. Building America Residential System Research Results: Achieving 30% WholeHouse Energy Savings Level in Marine Climates, January 2006 – December 2006, NREL/

SR-550-39743, prepared by the Building America research teams BIRA, BSC, CARB, Davis 

Energy Group, FSEC, IBACOS, NAHBRC and NREL for the U.S. Department of Energy, 

http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/39743.pdf

DOE. 2008. Builders Challenge Quality Criteria Guide – Version 1.3, U.S. Department of 

Energy, Building America Program, www.eere.energy.gov/buildings/challenge/pdfs/bcqc_

version_1_3_060408.pdf

Haas Davenport, Linda. 2000. The Scopes of Work Program: Procedures and 

Standard to Increase Quality. NAHB BuilderBooks, Washington, D.C., 

http://store.builderbooks.com/cgi-bin/builderbooks

Customer Engagement 

Definition: the emotional connection 

customers have with an organization.

Characteristics of Engaged Customers:

•	 Retention: They will spend more with 

you over their lifetime than with your 

competition. 

•	 Effort: They will go out of their way to 

do business with you and will spend 

more to benefit from your products, 

service, and brand. 

•	 Advocacy: They spread the good word, 

making it easier and cheaper for you to 

attract new customers. 

•	 Passion: They are passionate about the 

brand—so passionate that they may even 

spend time actively promoting the brand 

to others or defending the brand if others 

speak negatively about it. 

How to Create a Customer 

Engagement Process:

•	 Learn from the customers who 

walk away. Use customer feedback 

to improve your business. 

•	 Act on customer experiences to 

create engagement, not just 

measure satisfaction.

•	 Find out what actions, behaviors, 

and services are expected and plan 

for them. 

•	 Determine the associated performance 

standards and develop a way to 

measure them.

•	 Consistently deliver extraordinary 

customer service.

(PeopleMetrics 2011)

The Builders Challenge Quality Criteria 

Building America’s Builders Challenge Quality Criteria Guide promotes 

continuous improvement while ensuring construction quality and efficiency 

so builders and homeowners alike benefit from reduced callbacks and 

enhanced comfort, indoor environmental quality, and durability. The guide 

lists criteria for the three phases of construction (DOE 2008): 

•	 The design phase requires design, planning, and documentation 

before construction. 

•	 The construction phase frequently requires the builder/

superintendent to visually inspect and document proper 

installation by the trade contractors.

•	 The verification phase requires a third-party verifier to review 

and measure criteria after construction.

When implementing quality criteria, builders establish the expectations 

for quality practices, oversee their implementation, and keep records to 

confirm what was done. Trade contractors implement quality practices in 

accordance with their scope of work. Third-party verifiers—e.g., Residential 

Energy Services Network (RESNET)-certified HERS raters—confirm the 

implementation of the criteria via measurement, inspection, or confirmation 

of their implementation by builders. 

CHAPTER 3 / BUILDING AMERICA BEST PRACTICES SERIES

3.8 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
ISO 9000. Quality Management Systems. International Organization for Standardization, 

www.iso.org

ISO 9001. Quality Management Systems – Requirements. International Organization for 

Standardization, www.iso.org

J.D. Power and Associates. 2008. “2008 New-Home Builder Customer Satisfaction Study.” 

www.jdpower.com/homes/articles/2008-Homebuilder-Customer-Satisfaction-Study

Leonard, Denis, and Michael Dickens. 2011. Quality Management: Perspectives and Best 

Practices of Award-Winning Homebuilders. Alliance Best Practices Research Webinar. 

www.theresearchalliance.org/quality-mgmt-bps-recap.aspx

Leonard, Denis. 2011. The National Housing Quality Award (NHQA) & Self Assessment. 

HousingZone.com. Accessed 2001: www.housingzone.com/blog/2011/03/national-housingquality-award-nhqa-self-assessment

Lstiburek, Joseph W., and Betsy Pettit. 2008. Quality Assurance Roadmap for High 

Performance Residential Buildings. Building Science Corporation, Westford, Massachusetts. 

www.buildingscience.com/documents/guides-and-manuals/gm-building-america-qualityassurance-roadmap/at_download/file

Lukachko, Alex. 2008. Quality Assurance Roadmap for High Performance Residential 

Buildings. DRAFT, Building Science Corporation, Somerville, MA. 

www.buildingscience.com/documents/guides-and-manuals/gm-building-america-qualityassurance-roadmap/at_download/file.

Misronet Construction Information Services. 2011. Quality Management. Accessed 2001: 

http://www.misronet.com/quality_management.htm

NAHBRC. 2000. Quality Assurance System for Wood Framing Contractors: National 

Quality Housing. National Association of Home Builders Research Center. 

www.pathnet.org/si.asp?id=478

NAHBRC. 2008. Scopes of Work for High-Performance Homes. Prepared for the 

National Renewable Energy Laboratory by the National Association of Home Builders 

Research Center, Upper Marlboro, MD. www.toolbase.org/ToolbaseResources/level3.

aspx?BucketID=5&categoryID=62

NAHBRC. 2010. Multi-Year Advanced Residential Building Systems Research Subcontract 

Number: AXL-9-99208-01 Appendix A: The Economics of Quality Deliverable Number 4.5.2. 

Prepared for the Midwest Research Institute, National Renewable Energy Laboratory by 

the NAHB Research Center Upper Marlboro, MD. 

www.toolbase.org/PDF/BestPractices/AppendixAEconomicsofQuality.pdf

NAHBRC. 2011. Guidelines for Measures & Strategies – Quality Management Strategies in 

Existing Homes: A Quality Assurance Approach to Remodeling for Comfort, Durability, 

and Energy Efficiency. January 2011. Prepared for the U.S. Department of Energy Building 

America Program by the National Association of Home Builders Research Center, Upper 

Marlboro, MD.

PeopleMetrics. 2011. “Voice of the Customer,” accessed May 26, 2011 

www.peoplemetrics.com/voice-of-customer.htm

Prahl, Duncan, and Denis Leonard (Business Excellence Consulting). 2010. Quality 

Management for High Performance Homes – Quality, Environmental, Health & Safety (QEHS) 

Management System: Frequently Asked Questions. IBACOS, Inc., Pittsburgh, PA. 

www.theresearchalliance.org/.../IBACOS%20FAQ%20Report%2010-26-10%20v1.pdf

Prahl, Duncan. 2010. “Quality Management for High Performance Homes – Research Update.” 

Presentation at DOE Quarterly Meeting, Denver, Colorado. July 20, 2010, IBACOS Inc. 

http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/ns/a12_

implementing_total.pdf

U.S. Department of Trade and Industry. 2011. “Performance Measurement.” From Quality 

to Excellence. Accessed April 2011: www.dti.gov.uk/quality/performance

Vitalo, RL. 2011. Six Sigma and Kaizen Compared: Part 1 (Revised), Vital Enterprises, 

www.vitalentusa.com/learn/6-sigma_vs_kaizen_1.php#q_origins

Key Attributes of 

High-Performance Builders

•	 Cultural and corporate alignment

•	 Clear intent for quality and performance 

•	 Increased collaboration across internal 

and external teams

•	 Better communication practices and systems 

•	 Disciplined approach to quality control

•	 Measurement and verification of 

performance

•	 Continuous feedback and improvement

•	 Whole-house integrated design 

and specification.

(Prahl 2010)

Pine Mountain Builders worked with 

IBACOS and Southface Energy Institute, 

both Building America research partners, to 

overcome the technical challenges to meet 

and exceed the high standards of Longleaf, 

a sustainable resort community next to the 

Callaway Gardens Wetlands Preserve in 

west Georgia. (Photo Source: Pine Mountain 

Builders)

“With IBACOS we can experiment 

with new systems and products. 

We love the Building America 

program. We learn and improve 

every day.” 

Mike Guinan, manager, Pine Mountain 

Builders, Pine Mountain, Georgia

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Integrated Design

Before World War II, a house was often designed and built under 

the watchful eye of a single person. As construction projects have 

become more complex and expertise has become more specialized, 

the decision-making, design, and construction processes have been 

divided among managers, designers, site superintendents, vendors, 

subcontractors, and the trades. Along with increasingly diverse 

teams, building materials and construction techniques have also 

multiplied and become more technical. The integrated design 

process invites today’s larger design and construction teams to 

share information and insights to achieve the kind of whole-house 

perspective and understanding that previously came with a single 

master builder.

Integrated design assumes a systems engineering approach (DOE 

2011a), which unites segments of the industry that traditionally 

work independently of one another. Teams of architects, engineers, 

builders, equipment manufacturers, material suppliers, community 

planners, mortgage lenders, and contractor trades collaborate to 

research and design optimal building solutions.

The teams assess the structure as a whole, recognizing that the design 

of one component can greatly affect other aspects of the house. 

To help establish energy savings goals, teams may use the Building 

America House Simulation Protocols (DOE 2011a) as a standard 

of comparison.

Builders who use the integrated design approach focus on wholehouse performance. They start by looking at how all the systems in 

the house (HVAC, insulation, walls, ceilings, and windows) work 

together to achieve a house that performs well in terms of energy 

efficiency, air quality, and moisture management. The team must 

work together throughout the entire process to produce high-quality 

houses that incorporate energy- and material-saving strategies. At 

the very early stages of the project, the team evaluates the builder’s 

design, business, and construction practices to identify cost savings.

This investment in up-front planning is especially worthwhile for 

production builders because they reap the benefits with multiple 

applications of a house design.

In contrast, builders using typical design practices often start by 

emphasizing cost and size. With these external factors decided, they 

move through a linear process ending with house construction; 

building performance is considered as an afterthought or not at all.

When creating a highperformance home, view each 

building structure, its systems, 

and site as an interdependent 

system to ensure that all of its 

components work synergistically 

rather than against one another.

The goal is to gain value at 

every step of the design process 

(value engineering) rather than 

relying solely on negotiation and 

procurement to manage costs.

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3.10 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Traditional Versus Integrated Design Process

The Integrated Design Process loops in design input at every stage of development (Adapted from IEA 2003).

TRADITIONAL DESIGN PROCESS

➊ PROGRAMMING

➋ SCHEMATIC DESIGN

➌ DESIGN DEVELOPMENT

➎ CONSTRUCTION

 DOCUMENTATION

➐ CONSTRUCTION/COMMISSIONING

➑ ANALYZE PERFORMANCE

 TO ENSURE COMPLIANCE

➍ CONSTRUCTION

 DOCUMENTATION

➎ BIDDING & NEGOTIATION

➏ CONSTRUCTION

VALUE ENGINEERING

VALUE ENGINEERING

INTEGRATED DESIGN PROCESS

➏ BIDDING & NEGOTIATION

➊ PRE-DESIGN

➋ SET PERFORMANCE STANDARDS

➌ CONCEPTUAL DESIGN

➍ FINAL DESIGN

PERFORMANCE STANDARDS

Market Needs Incentives

Landscape

Branding

Efficiency

Energy Measures

HVAC

Moisture

Management

Sequencing

Community

Requirements

Cost

Comfort

Costs

Construction

Consideration

Advanced

Framing

HVAC Ducts

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Traditional Design Processes

Typically a design process includes the following steps.

1. PROGRAMMING:

In this conceptual development and planning stage, the price 

range, square footage, number of stories, lot sizes, general 

features, and styles are determined.

2. SCHEMATIC DESIGN: 

Preliminary designs are developed including floor plan sketches, 

number of bedrooms, major options, basic circulation and 

function locations, as well as some elevation concepts.

3. DESIGN DEVELOPMENT: 

Preliminary structural, mechanical, electrical, and plumbing 

plans are drawn.

4. CONSTRUCTION DOCUMENTS: 

Final working drawings and specifications are ready for bidding 

and code approval.

The traditional design process tends to be linear, with input coming 

sequentially. Sometimes design decisions are made before the 

input is available. Sometimes the input is not part of the formal 

design process, but comes in the field where access to information 

is limited and decisions must be based on the materials, expertise, 

and conditions at hand. For example, HVAC equipment may not be 

sized until the installer shows up on the project site, and important 

decisions such as routes and sizes for ducts may not occur until 

installation work begins in the field.

Integrated Design Process

A key idea behind integrated planning is that decisions about 

all building systems, including equipment selection, sizing, 

and placements, are made as part of the design process, not as 

afterthoughts in the field. The decisions are made with the help of 

analytical tools and the input of all relevant disciplines. Rather than 

a linear traditional process, the integrated process involves looping in 

ongoing input from relevant sources. As shown in the design process 

comparison figure on the previous page, a series of design loops 

exists for each step of the design process, separated by transitions 

(gray arrows) during which decisions are made about milestones. In 

each of the design loops, the design team members relevant for that 

step participate in the process.

“The idea is a whole-house 

system integration approach. We 

wanted to make sure the HVAC 

system and mechanicals were 

not an after-thought. A lot of 

builders put up the frame and 

don’t really consider where duct 

lines and supply risers need to go 

or how the plumbing lines and 

drain lines may be routed. Before 

the HVAC guy gets in there and 

starts hacking up floor trusses, 

plates, and walls, let’s put some 

thought into what needs to be 

routed where. The best approach 

is to start at the initial design of 

the building, making sure that 

all of these considerations are 

accounted for when you 

are planning.” 

Kevin Brozyna, a project manager for 

IBACOS, a Building America team lead

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3.12 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
The following are steps within the integrated design process.

PRE-DESIGN – Bring together a diverse and knowledgeable team. 

The makeup of the team and members’ roles will vary depending 

on the project or objective under consideration. Community 

design may benefit from ecologists, landscape architects, or solar 

planners. House designs may need input from architects or designers, 

structural engineers, framers, and HVAC contractors. Solving a 

particular installation challenge could involve the site supervisor 

and the relevant trades. For larger-scale efforts, select a facilitator to 

carry the process forward and set up a schedule of needed meetings.

SET PERFORMANCE STANDARDS – Early in the design process, 

establish standards that the house model will be expected to achieve. 

Measure progress against these standards at each step. Use market 

data to determine the level of quality, performance, size, and cost 

the houses will achieve. Performance areas may include moisture 

management, indoor air quality, energy efficiency, HVAC comfort, 

and any certification requirements (for example, achieving a Home 

Energy Rating Scale [HERS] index score to qualify for a tax credit).

CONCEPTUAL AND PRELIMINARY DESIGNS – Acquire 

team feedback during all phases of design and construction. 

Use an energy specialist to test design assumptions and simulate 

possible solutions. It is important to work with framing and other 

contractors, especially HVAC contractors, to identify conflicts 

and develop solutions before houses go into production. You may 

want to consult with code officials for any nonstandard techniques 

or materials. By integrating design decision-making, all parties 

benefit. For example, the mechanical contractor can aggressively 

size the HVAC equipment knowing that the thermal envelope is well 

insulated, properly air sealed, and third-party inspected.

FINAL DESIGN – Create specific drawings and system designs. 

Generate architectural, framing, HVAC, electrical, and plumbing 

drawings that specify locations for equipment chases and runs. 

Develop framing plans showing the location of every stud, floor 

truss, and roof truss. HVAC drawings should specify duct sizes 

and locations, including chases designed to carry ducts inside 

conditioned space. Some builders create a single system design 

that can be approved, installed, and warranted by any installing 

contractor on most of their home models. This can apply for many 

systems including framing, electrical, plumbing, and HVAC. 

CONSTRUCTION DOCUMENTATION – Base construction 

documents on the final design. Include statements of work for all 

subcontractors. Specify installation requirements. Use job-ready 

and job-complete checklists for self- and third-party verification.

Building America research team lead 

IBACOS helped Insight Homes in Seaford, 

Delaware, to evaluate building durability 

and bulk water management details. 

IBACOS also helped develop duct 

designs and system layouts for several 

of Insight Homes’ models to address 

recurring comfort issues with the heating, 

ventilation, and air conditioning (HVAC) 

system. IBACOS continues to work 

with Insight Homes to establish quality 

assurance measures that will help the 

company consistently deliver high quality 

as they build homes in greater volume.

(Photo Source: Insight Homes)

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CONSTRUCTION/COMMISSIONING – Build the houses to the 

designs. After ducts are in and sealed but before insulation and 

sheetrock are added, conduct duct leakage tests. After insulation 

is added, conduct visual inspections for compaction and voids. 

After sheetrock and wall surfaces are added, check whole-house 

air leakage, temperature evenness, room pressures, ventilation, and 

carbon monoxide levels. Confirm that specified appliances and 

lighting are installed. Use the NAHB-developed HotSpot tool to 

check and fix problem areas (see Chapter 11 for example).

PERFORMANCE ANALYSIS TO ENSURE COMPLIANCE – 

Use computer models to simulate the energy consumption of your 

designs. As construction is completed, confirm performance with 

the quantitative measurements listed under commissioning above, 

including duct blaster and blower door testing using the SnapShot 

form developed by Building Science Corporation (see Chapter 11 

for description of tests) or use verification forms for any labeling 

programs in which you are participating.

For More Information on Integrated Design

AIA. 2007. The Integrated Project Delivery Guide, the American Institute of Architects, 

www.aia.org/contractdocs/AIAS077630

AIA. 2010. Integrated Project Delivery: Case Studies, the American Institute of Architects, 

www.aia.org/about/initiatives/AIAB082049

ANSI. 2007. ANSI/MTS 1.0. Whole Systems Integrated Process Guide (WSIP) 2007 for 

Sustainable Buildings & Communities. Institute for Market Transformation to Sustainability. 

American National Standards Institute, http://webstore.ansi.org/RecordDetail.aspx?sku=ANS

I%2FMTS+1.0+WSIP+Guide-2007

BC Green Building Roundtable. 2007. Roadmap for the Integrated Design Process, 

Part One: Summary Guide. Prepared by Busby Perkins+Will and Stantec Consulting for 

Metro Canada. Vancouver, B.C. www.metrovancouver.org/buildsmart/design/Pages/

Integrateddesignprocess.aspx

DOE. 2004. “Habitat Metro Denver—Perfecting Award-Winning Affordable Homes Using 

Building America’s Integrated Design Approach.” Building America factsheet DOE/GO-102004-

2030. http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/36102.pdf

DOE. 2006. Building America Residential System Research Results: Achieving 30% WholeHouse Energy Savings Level in Marine Climates, January 2006 – December 2006, NREL/

SR-550-39743, prepared by the Building America research teams BIRA, BSC, CARB, Davis 

Energy Group, FSEC, IBACOS, NAHBRC and NREL for the U.S. Department of Energy, 

http://apps1.eere.energy.gov/buildings/publications/pdfs/building_america/39743.pdf

DOE. 2011. Systems Engineering Approach, U.S. Department of Energy, Building America Program, 

accessed 5-255-11, www.eere.energy.gov/buildings/building_america/systems_engineering.html

International Energy Agency (IEA). 2003. Integrated Design Process Guideline. Prepared 

by sol*id*ar planungswerkstatt architects and engineers and Architeckten B+S for the IEA. 

www.iea-shc.org/task23/design.htm

NIBS. 2010. Engage the Integrated Design Process. National Institute of Building Sciences. 

www.wbdg.org/design/engage_process.php

Prowler, Don. 2011 (revised). “Whole Building Design.” Whole Building Design Guide – a program of 

the National Institute of Building Sciences, Washington, DC. www.wbdg.org/wbdg_approach.php

The WBDG Aesthetics Subcommittee. 2010. “Engage the Integrated Design Process.” 

Whole Building Design Guide – a program of the National Institute of Building Sciences, 

Washington, DC. www.wbdg.org/design/engage_process.php.

“We like to build the most energyefficient and best-performing 

home with off-the-shelf parts. It 

looks like an ordinary house but it 

performs way better.” 

Mike Guinan, Manager, Pine Mountain 

Builders, Pine Mountain, Georgia

Pine Mountain Builders has worked with 

IBACOS and Southface over the past 

few years to reach both the 30% and 

40% energy savings over the Building 

America benchmark. They are now 

working together toward the 50% energy 

savings level in future designs. Pine 

Mountain Builders leverages long-standing 

relationships with its trade partners to 

ensure its performance standards are met 

with conventional building materials.

CHAPTER 3 / BUILDING AMERICA BEST PRACTICES SERIES

3.14 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Value Engineering

Value engineering has its roots in World War II. While coming up 

with creative substitutions for building supplies in the face of wartime 

shortages, staff at General Electric developed a process that had the 

unintended consequences of reducing costs, increasing productivity, and 

improving products. Value engineering has evolved into a systematic 

method for improving the value of goods and services by examining 

approaches to meeting function. Value can be increased by either 

meeting function more efficiently or reducing cost. Value engineering 

within the construction design process was developed in the 1960s. 

Process Overview

As a management tool for multidisciplinary teams, value engineering 

begins with gathering information about the requirements for a 

product, system, or process to analyze the importance of its function 

or performance characteristics in response to questions like “What 

does the object do? What must it do? What should it do? What 

could it do? What must it not do?” Once the functional baseline is 

established a new set of questions is asked and answered to generate 

alternatives design concepts, materials, and methods (“What are the 

various alternative ways of meeting requirements? What else will 

perform the desired function?”). How well each alternative meets 

the required functions and the associated cost savings are evaluated 

next, prior to selection of the best alternative to inform final 

decision-making for value improvement, wherein the “best value” 

is represented by an item or process that consistently performs the 

required basic function and has the lowest life-cycle cost.

Reducing Construction Costs 

While Improving Functionality

Optimum value engineering for framing, also referred to as advanced 

framing, is one example of how value engineering can reduce 

construction costs while maintaining or improving functionality. 

These framing techniques (described in more detail in Chapter 7) 

reduce the amount of lumber used to build the home while allowing 

more space for insulation, resulting in lower material and labor costs 

and improved energy performance. Advanced framing can be an 

important design feature, but value engineering can be applied to all 

aspects of home design. 

Much of Building America’s research is aimed at helping builders 

choose more efficient construction materials and methods to make 

their buildings more efficient. Building America’s research considers 

energy efficiency as well as other important aspects of functionality, 

“Synonymous with the terms 

value management and value 

analysis, value engineering is a 

professionally applied, functionoriented, systematic team 

approach used to analyze and 

improve value in a product, facility 

design, system, or service—a 

powerful methodology for solving 

problems and/or reducing costs 

while improving performance/

quality requirements. By enhancing 

value characteristics, value 

engineering increases customer 

satisfaction and adds value to your 

investment. Value engineering 

can be applied to any business or 

economic sector, including industry, 

government, construction and 

service. Using value engineering 

is a very successful long-term 

business strategy.”

Lawrence D. Miles Value Engineering 

Reference Center 2011

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Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 3.15
such as structural needs, durability, comfort, and health. Improved 

quality control also means fewer callbacks, which leads to more 

customer referrals.

Value engineering is an important part of quality management and 

integrated design. Production builders are in a good position to take 

advantage of value engineering. The investment made up front in 

the design process pays off in the many homes where the improved 

designs are applied. Value engineering is not just about reducing 

cost, it is about selecting the systems with the best value and 

recognizing synergies within the integrated design process.

For More Information on Value Engineering

Cullen, Scott. 2006. “Value Engineering.” The Whole Building Design Guide, the National 

Institute of Building Sciences, Washington, D.C. 

www.wbdg.org/resources/value_engineering.php

El-Alfy, Alaa El Dean. 2010. “Design of sustainable buildings through Value Engineering.” 

Journal of Building Appraisal 6:69-79. 

www.palgrave-journals.com/jba/journal/v6/n1/pdf/jba201014a.pdf

Lawrence D. Miles Value Engineering Reference Center. 2011. “What is Value Engineering.” 

Wendt Library, University of Wisconsin, Madison, WI. Accessed 2011: 

http://wendt.library.wisc.edu/miles/index.html

Moser, Cliff. 2007. “Using Active Value Engineering for Quality Management,” Practice 

Management Digest, American Institute of Architects. 

SAVE International. 2007. Value Standard and Body of Knowledge.

www.value-eng.org/pdf_docs/monographs/vmstd.pdf

Managing Innovation with Prototypes

For building energy technologies to be viable innovations, they must 

be demonstrated to cost-effectively increase overall product value 

and quality while significantly reducing the use of energy and raw 

materials. Prototyping involves the development of functionally 

useful and trustworthy building designs through experimentation with 

evolving systems and products. It is used to demonstrate that affordable 

housing can be designed and constructed to reduce operating costs, 

while maintaining comfort, healthy indoor air quality, and durability 

(see “Test Houses and Community-Scale Housing” at DOE 2011a).

Many builders choose to try out Building America technical ideas 

in a prototype house prior to moving to full production mode. The 

prototype experience enables the builder to experiment with new 

materials, products, and construction practices with minimal costs 

and risks. After building one or a few prototypes, the builder decides 

which features to carry forward into standard construction. The 

chart below shows a process for working with building scientists, 

such as a Building America team, a HERS rater, an engineer, 

architect, or trained staff member, to build a prototype house.

Value Engineering Saves 

Builders Money While 

Increasing Quality

Value engineering allows builders to 

identify improvements to the design of 

a home that will ultimately save money. 

For example, 

•	 Designing for a tighter building envelope 

allows for smaller, less expensive heating 

and cooling systems.

•	 Advanced framing requires less 

wood and labor and allows more room 

for insulation. 

•	 Placement of heating and cooling 

systems inside the thermal envelope 

allows shorter duct runs saving material 

and installation costs. 

The founder of Insight Homes, Rob Lisle 

of Sussex County, Delaware, started his 

company with an experiment. He set out 

to build 36 identical homes, three at a 

time, with energy improvements and cost 

reductions in each, until he achieved a 

HERS score of 56 at a price comparable 

to market rate. He achieved that goal 

by house 27 and worked with Building 

America’s IBACOS team to further refine 

the home’s systems to achieve average 

HERS scores of 50 on the 40 to 70 

homes per year he is now building. 

(Photo Source: Insight Homes)

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3.16 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Process for Building a Prototype High-Performance Home

BUILDER/DEVELOPER

PHASE #1

Decision

BUILDING SCIENCE 

PERSPECTIVE

ENGINEER / ARCHITECT / 

HERS RATER / HVAC CONTRACTOR

PHASE #2

Integrated Design

& Analysis

PHASE #4

Construction

PHASE #5

Post-Construction

Evaluation

PHASE #3

Marketing

PHASE #6

Lessons Learned

Commits to go forward with best 

practices, sets goals, and expands 

design team to include building scientists

Management evaluates costs and 

benefits and decides on next steps

Management tracks financial benefits

Management ensures proper materials 

are purchased and available

Marketers create marketing 

program to emphasize improvements

Planners integrate lessons learned in 

selection and siting of future communities

Designer evaluates changes in style 

and materials, consults code officials 

for preliminary review.

Designer adds new features 

to production plans

Site supervisors evaluate skills, 

subcontractors, and code issues

Construction documents include detailed 

plans, specifications, and scopes of work

Site supervisors train crews, set clear 

expectations, and check quality

Trades professionals implement best practices 

in their installation and construction processes

Together, trades and supervisors use 

pre-job and post-job checklists

Offers design solutions based 

on whole-building analysis, including 

materials compatibility and durability, 

and system tradeoff modeling 

Communicates design approach 

to supervisors and crew – helps 

work out installation sequences

Educates builder about building 

science and systems approach

Determines impact of design 

solutions, including energy savings

Provides test results and 

data for marketing

Observes construction practices, 

recommends improvements, 

and offers training

Offers help with upgrading 

production plans with solar 

and energy-efficient design

Conducts field tests and inspections 

including blower door, duct pressure, 

and HVAC system tests

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For More Information about Prototypes 

BSC. 2009. “Designs That Work, Hot-Humid Climate: ICI Showcase House Prototype,” 

Building Science Corporation, 

www.buildingscience.com/documents/case-studies/cs-fl-daytona-ici-showcase

BSC. 2009. “Designs That Work, Mixed-Humid Climate: Colleyville Eco House Prototype.” 

Building Science Corporation, 

www.buildingscience.com/documents/case-studies/cs-tx-colleyville-greencraft

BSC. 2010 (Revised). “Habitat for Humanity Cold Climate R-Value Prototype, Westford 

Massachusetts.” Building Science Corporation Case Study. www.buildingscience.com/

documents/case-studies/cs-ma-westford-hfh/files/100709_MA_Westford_Case_Study.pdf

BSC. 2010. “Bedford Farmhouse High Performance Retrofit Prototype, Bedford 

Massachusetts, Case Study.” Building Science Corporation. 

www.buildingscience.com/documents/case-studies/cold-climate-bedford-farmhouseretrofit-case-study/files/100427r_MA_Bedford_Farmhouse_Case_Study.pdf

DOE. 2000. “New Building Approach Saves Energy and Cost, Retreat at the Bluffs 

Prototype Pulte Homes – Tucson, Arizona.” U.S. Department of Energy Building America. 

www.nrel.gov/docs/fy00osti/28576.pdf

DOE. 2000. “Prototype House Provides Test Case for Energy-Efficient Systems Mitchell 

Homes – Pensacola, Florida.” U.S. Department of Energy Building America. 

www.nrel.gov/docs/fy00osti/27209.pdf

DOE. 2008 “High Performance Builder Spotlight, Community Development Corporation of 

Utah,” U.S. Department of Energy Building America. www.buildingamerica.gov; apps1.eere.

energy.gov/buildings/publications/.../ba_bc_cdc_utah_cold.pdf

DOE. 2010. 2010 Residential Buildings Energy Efficiency Meeting, Denver, Colorado, July 

20 – 22, 2010, prepared for the U.S. Department of Energy Building America, by National 

Renewable Energy Laboratory, Golden, Colorado.

DOE. 2011a. “Building America Research is Leading the Way to Zero Energy Homes U.S. 

Department of Energy, http://apps1.eere.energy.gov/buildings/publications/pdfs/ building_

america/37547.pdf

DOE. 2011b. “High Performance Builder Spotlight Treasure Homes Inc, ‘The Gem,’ Burns 

Harbor, Indiana.” U.S. Department of Energy Builders Challenge, http://apps1.eere.energy.

gov/buildings/publications/pdfs/ building_america/ba_bc_treasure_cold.pdf

Go from Prototype to Full Production

It is important to test the energy-saving performance of prototype houses using 

carefully developed performance measures. Use these measures to evaluate your 

overall costs and identify opportunities for systems integration. Applying such 

measures helps identify any limitations of and gaps in the advanced technologies 

you have selected to achieve your whole-house energy-savings goals. After 

successful performance testing on your prototype home, you will be ready for 

community-scale production to extend the success of your individual test house 

evaluations via more broad-based implementation.

Insight Homes of Seaford, Delaware, is 

working with Building America team 

lead IBACOS to build and test two 

side-by-side houses: one with Insight’s 

standard energy-efficiency features 

and the other with an advanced HVAC 

system which includes a super-efficient 

heat pump paired with a tankless water 

heater that can provide backup heating. 

Insight and IBACOS are working with 

the manufacturers to develop it as a 

new product.

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3.18 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Building America has worked with hundreds of builders who have 

successfully used energy efficiency to sell houses. Consumers want the 

value and comfort high-performance homes offer. Builders want happy 

customers and the positive referrals they will give. 

However, the sales do not happen by themselves. To recoup the 

investment builders make in energy efficiency and quality management, 

they should do the following:

•	 Brand and label their products for fast and easy differentiation. 

•	 Train their sales staff to educate consumers.

•	 Market the sometimes hidden energy-efficient features of the home.

•	 Get their business name and products in front of the public.

Branding and Labeling

Branding and labeling offer two methods for gaining consumer 

attention and confidence. When consumers recognize a brand and 

associate that brand with positive attributes, they are more willing 

to consider purchasing that product. 

Creating a recognizable brand that resonates with consumers is 

difficult. Large corporations that rely on consumer sales spend 

millions of dollars on campaigns to keep their brands fresh but 

familiar. This investment pays off best when products involve 

multiple, frequent purchases from many consumers. Most builders 

do not fit this equation very well—builders typically sell their 

products in limited markets, and homebuyers tend to hang onto 

their purchases for a long time.

Chapter 4.

Selling Performance

“People love the energy efficiency 

of our homes.” 

Abe Gilbert, co-owner, Urbane Homes, 

Louisville, Kentucky

“The builders have reaped great 

rewards—increased sales, 

increased profits, quicker 

turnaround times, and a reduction 

in callbacks and complaints.” 

Ken Fonorow, Florida HERO, 

a Building America research partner

CHAPTER TOPICS

4.1 Branding and Labeling

4.3 Training Sales Staff

4.4 Marketing Energy Efficiency

4.5 Reaching Out to the Media

R

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CHAPTER 4. SELLING PERFORMANCE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 4.1
DOE’s Builders Challenge, ENERGY STAR, and other national and 

regional programs offer builders a recognizable label or brand tied 

to a known set of standards. Qualifying for these nationally known 

programs will give your energy-efficiency efforts instant credibility, 

and they are excellent vehicles for leveraging your marketing dollars.

Homes that achieve a 70 or lower on the HERS Index and that meet 

specified quality criteria can qualify for DOE’s Builders Challenge. 

The Builders Challenge label shown below is attached to qualifying 

homes. In addition to identifying the Builders Challenge brand, 

the label also provides useful information for consumers. The label 

incorporates the E-Scale, a ranking of energy efficiency based on 

the HERS index. Like a miles-per-gallon rating, this index gives 

consumers an easy way to compare and distinguish competing houses. 

The ENERGY STAR logo is a label that most consumers recognize 

for products that are energy efficient and good for the environment. 

This label can be found on many consumer products ranging from 

computers and dishwashers to lights and homes. ENERGY STAR 

for Homes is a label that recognizes the energy efficiency of the 

whole house. 

The ENERGY STAR (www.energystar.gov) website provides 

brochures and materials that builders can download for marketing. 

ENERGY STAR Update

In April 2010, the 

U.S. Environmental 

Protection Agency 

(EPA) announced 

new, more rigorous 

guidelines known 

as ENERGY STAR 

for New Homes 

Version 3.0. The 

updated requirements will ensure that 

the government’s ENERGY STAR label 

continues to deliver a significant increase 

in energy efficiency over homes that 

are built to code and standard builder 

business practices. Homes that qualified 

for ENERGY STAR Version 2.0 are about 

15% more energy efficient than the 2006 

IECC requirements. Homes that earn the 

ENERGY STAR label under Version 3.0 will 

show energy savings of 20% compared 

to homes built to the 2009 IECC. These 

guidelines are being phased in during 

2011 and, on January 1, 2012, will become 

effective for all homes permitted on or 

after that date.

Homes permitted before April 1, 2011, can 

continue to be qualified under Version 2.0 

until December 31, 2011. Homes permitted 

between April 1, 2011, and December 31, 

2011, can be permitted under a transitional 

Version 2.5.

For more information about ENERGY STAR 

for Homes, see: www.energystar.gov

Meets The Builders Challenge

Recognizing the best energy performance, quality, comfort, health, and safety in the market.

Conditioned floor area (sq. ft.): 3,312

SM

Estimated average 

monthly energy bill:

$104

Estimated annual energy usage:

Electric (kWh) 7728

Natural gas (Therms) 237

123 Main Street, Gainesville, FL 32601

Rated by Home Performance, Inc.

Rating conducted June 8, 2008

www.buildingamerica.gov/challenge

64

Your Home!

ADBuilder ADBuilder

#00000000000

Maximized

Energy-Efficient

Home

R

Insight Homes, of Seaford, Delaware, 

uses the HERS Index to market its 

homes, which typically achieve HERS 

scores of 49 to 56.

CHAPTER 4 / BUILDING AMERICA BEST PRACTICES SERIES

4.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Other green building programs that provide marketing and labeling 

support, including the National Association of Home Builders’ 

National Green Building ProgramTM (NAHB 2009), the U.S. Green 

Building Council’s Leadership in Energy and Environmental Design 

(LEED) for Homes program, and Masco’s Environments for Living®

. 

Many Building America builders choose to offer their homeowners 

an energy-use guarantee. Some builders do this on their own; others 

work through Masco Home Service’s Environments for Living 

program. Masco developed the program in 2001 with help from 

Advanced Energy Corporation and Building Science Corporation, 

a Building America team lead. Under Environments for Living, the 

home’s heating and cooling energy use are estimated, and Masco 

guarantees the homeowner that Masco will pay them the difference 

if their energy bills are higher than the calculated estimate.

For homes at the Environments for Living (EFL) gold and 

platinum level, Masco also offers a comfort guarantee promising the 

temperature at the thermostat will not vary more than three degrees 

from the temperature at the center of any conditioned room within that 

thermostat zone. According to Masco, homes built to the EFL gold 

level specifications will be at least 12% more energy efficient than homes 

built to the 2009 IECC. Homes built to platinum level are 18% more 

energy efficient, and homes built to the EFL Certified Green level are 

at least 20% more efficient (EFL 2011).

Training Sales Staff

Having properly trained sales staff is key to helping buyers 

understand and appreciate the value of energy-efficiency features. 

Building America builder, Vern McKown, co-owner of Ideal Homes 

in Norman, Oklahoma, shared some of his tips for training and 

marketing at the Energy and Environmental Building Alliance 

(EEBA) National Conference in Denver, Colorado, in September 2009: 

Train sales staff. 

- Field train every sales person every six months, no matter how long 

they’ve been with the company.

- Conduct new-hire sales training boot camp.

Give sales staff simple messages to convey, for example:

- Here’s how we are different—show infrared camera photos.

- Blown-in insulation fills in nooks and crannies better than batt.

- Our duct leakage is 5%, the average is 27%.

- Our windows are high performance—less heat in, less energy loss out.

- Utilities are guaranteed.

Some Building America builders use the 

Environments for Living guarantee—the 

builder promises the homeowner low utility 

bills and agrees to pay the difference if the 

bill is higher than promised. 

Pine Mountain Builders 

qualifies its homes 

for EarthCraft House, 

a regional program 

developed by Building 

America research 

partner Southface 

Energy Institute, that 

grades and certifies 

homes based on energy efficiency, indoor 

air quality, water efficiency, and other 

metrics for sustainability throughout the 

construction process. 

Countertop displays and model home 

information centers can educate 

homebuyers and realtors on the benefits 

of energy-efficient features.

4.3

CHAPTER 4. SELLING PERFORMANCE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 4.3
Get sales staff to walk buyers through the home.

- Identify four key exterior features and nine key interior features.

- Use mystery shoppers to find out what your sales folks are actually 

telling shoppers. 

- Keep it simple—“We tell sales folks, if you aren’t sure of the specifics 

just say ‘we’re better’ and stop there.”

Staff your website. 

- Keep your website up to date.

- Make it active with a phone or email link to a live person.

- Respond to web inquiries within five minutes.

Do your own research.

- Do exit interviews with customers, buyers, and lookers.

- Drill down for specifics in problem areas.

- Do NAHB quality certification audits of the whole company on 

a regular basis.

Ensure cultural and corporate alignment.

- Identify your company’s core values and hire people who share those values. 

- Ask your employees where the weak spots are and fix them. 

- Ask your employees how you can help them do their jobs better.

Marketing Energy Efficiency

A challenge for builders of energy-efficient homes is showing 

consumers the energy efficiency they are purchasing. Most energyefficiency improvements are hidden away in walls and attics invisible 

to buying eyes. Making energy improvements “real” to the consumer 

is a multi-faceted, ongoing process that can include any of the 

following (NAHBRC 2010):

•	 Emphasize cost, comfort, health, and environmental benefits. 

•	 Educate customers and sales professionals. Use duct blaster, 

blower door, and HERS scores to show differences.

•	 Use walk-throughs and model homes with display cutaways of energy 

features such as insulated attics and wall sections to help buyers and 

sales staff understand the energy-efficient construction process.

•	 Turn the model home’s garage into an energy information center. 

Use side-by-side displays on walls, demo walls showing wall and 

window features, touch screen videos, and poster board displays.

•	 Organize tours for homebuyers, school groups, media, and 

realtors. Use slides, sample products, and energy bills as aids.

Tommy Williams sales staff regularly tour 

finished and unfinished homes to learn 

about the energy-efficiency features. 

“We make sure our sales team 

knows the details, and we present 

a consistent message from home 

to home and neighborhood to 

neighborhood.”

John Friesenhahn, president, Imagine 

Homes, San Antonio, Texas

CHAPTER 4 / BUILDING AMERICA BEST PRACTICES SERIES

4.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
•	 Emphasize an energy-efficiency upgrade when signing the final 

papers. One builder has a wall of testimonials, photos, and examples 

of utility bills in his waiting room. Another builder has the buyer 

meet with the building site supervisor after the sale is made for one 

more chance to sign up for energy-efficiency upgrades. 

•	 Provide take-home brochures that explain energy-saving features. 

Develop your own factsheets or give away Building America 

and ENERGY STAR brochures, reprints of magazine articles, 

and vendor and trade association brochures. Also, give potential 

buyers a checklist so they can compare the energy-saving measures 

in your homes with those of other builders (see Appendix I). 

•	 Use paid advertising with a simple slogan. One builder created an ad 

campaign based on “$60,” a figure they guaranteed monthly electric 

bills would not exceed for the first year. They ran ads on billboards, 

the sides of buses, signs on their property, and in the newspaper. 

•	 Use the Internet—websites, YouTube videos, Facebook, Twitter, etc. 

•	 Seek out free publicity, send out press releases, hold media events. 

•	 Participate in building-related charity events.

•	 Get involved in your local home builders association.

•	 Offer energy-efficiency guarantees. 

•	 Make buyers aware of energy-efficient mortgages.

•	 Package energy-efficiency features through a national or regional 

program or your company’s own energy-efficiency “brand.”

Reaching Out to the Media

Nothing is more cost effective than sending out a news release to local 

media to announce business news and other company activities. News 

related to energy efficiency can include partnering with national or 

regional energy-efficiency programs, reaching a new best score for 

your area on the HERS Index, hitting milestones in numbers of 

energy-efficient houses built, winning awards for energy-efficient and 

green construction, trying out new technologies, offering tours of 

houses under construction, or hiring an energy guru, or participating 

in research projects with colleges or DOE. News releases can cover 

your company’s involvement in educational and charitable activities, 

for example, teaching school children about energy efficiency or 

building homes with Habitat for Humanity.

Rob Lisle, the owner of Insight Homes in Seaford, Delaware, is 

a frequent speaker at building conferences on the topic of energy 

efficiency. In 2009, he began hosting a local weekly radio show where 

he answers callers’ questions about green and energy-efficient building.

Ideal Homes of Norman, Oklahoma, has 

worked with Building America since 2002 

to steadily improve the energy efficiency 

of its homes. Intensive, persistent, initial 

and ongoing training of its sales staff has 

helped Ideal differentiate its product and 

become one of the biggest builders in 

the state. (Photo Source: Ideal Homes)

Through 2011, Building 

America builders have 

won 121 Energy Value 

Housing Awards (EVHA) 

from the National 

Association of Home 

Builders Research Center. 

4.5

CHAPTER 4. SELLING PERFORMANCE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 4.5
For More Information on Marketing

EFL. 2011. Environments for Living. www.environmentsforliving.com

ENERGY STAR www.energystar.gov

EPA. 2011. “What is Indoor airPLUS?” U.S. Environmental Protection Agency, 

updated March 3, 2011, www.epa.gov/indoorairplus/about.html

EPA. 2011. “WaterSense: An EPA Partnership Program, New Homes,” U.S. Environmental 

Protection Agency, updated July 7, 2011, www.epa.gov/watersense/pp/new_homes.htm

Farnsworth, Christina. 2003. “The Weakest Link.” Builder Magazine, December 2003, 

www.builderonline.com/business/the-weakest-link.aspx?printerfriendly=true

NAHB. 2009. ICC 700-2008 National Green Building Standard, the National Association 

of Home Builders and the International Codes Council, www.nahb.org

NAHBRC. 2007. Building America Challenge Survey of Builders and Consumers. National 

Association of Home Builders Research Center. www.nahbrc.org

NAHBRC. 2009. Green Building Program. National Association of Home Builders 

Research Center, www.nahbgreen.org

NAHBRC. 2010. Energy Value Housing Award Program. National Association of Home 

Builders Research Center, www.nahbrc.org/EVHA

Sikora, Jeannie. 2002. Energy Value Housing Award Guide: How To Build and Profit with 

Energy Efficiency in New Home Construction. National Association of Home Builders 

Research Center, www.nahbrc.org

USGBC. 2011. “Green Home Building Continues to Flourish.” U.S. Green Building Council 

Press Release April 5, 2011. www.usgbc.org/Docs/News/LEED%20for%20Homes%2010k%20

milestone_April%202011.pdf

The prototype model home built by Urbane 

Homes in Crestwood, Kentucky, won three 

major building awards in 2009, including 

two NAHB Energy Value Housing Awards 

(for affordability and production), and 

it was runner-up for the NAHB’s Green 

Project of the Year.

CHAPTER 4 / BUILDING AMERICA BEST PRACTICES SERIES

4.6 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
There are 22 states that are wholly or partially in the Building 

America mixed-humid climate. Conditions vary across this 

climate zone, which stretches from New York to South Carolina 

and from the Mid-Atlantic states to the Midwest as far as Kansas, 

Oklahoma, and northern Texas.

Builders in the mixed-humid climate must be able to address 

solar gains in the summer, medium to high humidity, mild to cold 

temperatures in the winter, torrential downpours, high winds, and 

tornadoes, especially in the midwestern and southern states. 

The recommendations in this Best Practices guide apply to 

the mixed-humid climate region. If you are not sure that your 

project is within this climate region, check the Building America 

Best Practices Series, Volume 7.1, Guide to Determining Climate 

Regions by County (DOE 2010, www.buildingamerica.gov) for a 

list of counties and climate zones. 

In addition to describing the mixed-humid climate, this chapter 

also provides information on building for the weather conditions 

that can occur in this climate. Siting and design considerations 

with respect to solar gain are also included. See Chapters 7 and 

8 for information on moisture management, air sealing, and 

thermal control techniques for foundations, walls, and roofs.

Design Considerations 

for the Mixed-Humid Climate

The temperature variations, forces of driving wind and rain, and 

medium to high humidity levels can take their toll on buildings. 

Builders must accommodate significant heating and cooling 

Chapter 5.

The Mixed-Humid 

Climate

CHAPTER TOPICS

5.1 Design Considerations 

for the Mixed-Humid Climate

5.4 Climate Description

5.5 Weather 

5.9 Considering Solar Gain

in Siting and Design

Brick veneer is a popular cladding in 

the mixed-humid climate. (Photo Source: 

Urbane Homes)

5.1

CHAPTER 5. THE MIXED-HUMID CLIMATE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 5.1
needs and combat the effects of heavy rain and condensation from 

humidity, which can degrade structural materials, contribute to mold 

growth, and cause premature aging. Based on work with its mixedhumid case study builders, Building America makes the following 

recommendations for designing homes in the mixed-humid climate:

•	 Build slab-on-grade foundations and grade lots to drain away from 

the structure.

•	 Create a tight thermal envelope and install a positive pressure 

ventilation system.

•	 Place the air handler and ducts in conditioned space or go ductless 

with mini-split heat pumps.

•	 In cooling-dominated areas, install a reflective roof and use light or 

reflective exterior wall colors.

•	 Provide adequate spot ventilation; consider timer-controlled 

exhaust fans.

•	 Use rigid foam and braced framing instead of OSB for 

exterior sheathing.

•	 Consider high-efficiency heat pumps that can provide heating and 

cooling across the moderate mixed-humid temperature range.

•	 Use low-maintenance, high-durability exterior products – for 

example cement fiber board siding and composite decking materials.

•	 Plan for storm-water runoff with adequate gutters, flashing, and 

kick-out diverters. Use pervious paving, vegetation, grading, and 

swales to handle large storm events.

•	 Use impact-resistant glass as required by code.

•	 In tornado-prone areas, consider incorporating basements, storm 

cellars, or safe rooms into designs.

•	 Install high-performance, low-emissivity windows with low solar 

heat gain coefficient.

•	 Install overhangs, covered porches, awnings, pergolas, or shade 

trees to minimize solar heat gain.

•	 Install a dehumidifier to control shoulder-season humidity.

•	 Use paints that contain mildewcides.

•	 Use door jambs that are designed for water and rot resistance.

•	 Use cement backer board behind tubs and showers.

Insight Homes used advanced framing and 

located high-efficiency furnaces and ducts 

in a sealed, insulated crawlspace in its 

homes in Sussex County, Delaware. 

(Photo Source: Insight Homes)

CHAPTER 5 / BUILDING AMERICA BEST PRACTICES SERIES

5.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
•	 Install a pest defense system in the walls. 

•	 In framed homes, use borate pressure-treated lumber.

•	 Install a thermostat with humidity controls.

•	 When installing windows use sill wrap, corner shields, and 

adhesive flashing tape to protect against water intrusion.

•	 Install hurricane strapping, rods, and bolts per code.

•	 On roofs use fully adhered roofing membrane at eaves and gable 

ends, butyl-based adhesive-back flashing strips on roof sheathing 

joints, and hurricane-rated shingles.

•	 Use non-heat-producing CFL lights.

•	 Install ceiling fans.

•	 In flood- and hurricane-prone areas, install a generator-ready 

electrical service panel to run generator-powered shopvacs, fans, 

and heaters to dry out the house and reduce water damage during 

post-storm recovery when electric power outages are common.

•	 In hurricane areas, consider steel-reinforced concrete walls, 

outswing doors, hurricane shutters, eave designs with extended 

fascia providing drip edge, and recessed soffit vents (Zoeller 2006).

Building America Examples of Weather-Resistant 

Construction in the Mixed-Humid Climate

Building America worked with four mixed-humid climate production 

builders, whose construction practices are described in case studies at 

the back of this guide. These builders worked with Building America’s 

research partners to incorporate several features that accommodate 

the temperature variations and moisture control issues inherent 

in the mixed-humid climate. All four builders consistently achieve 

HERS scores under 60. Three of the four use advanced framing 

techniques including 2x6 24-inch on-center construction. Three of 

the builders use XPS rigid foam as an exterior sheathing that is more 

water resistant than OSB. Two builders use spray foam wall cavity 

insulation, which air seals and insulates. Three of the builders exceed 

R-38 attic insulation using blown fiberglass or blown cellulose and the 

fourth uses R-30 low-density spray foam to provide a conditioned attic 

space to house ducts. 

All four builders locate their ducts in conditioned space, with two 

locating ducts in open-web floor joists, one in the conditioned attic 

and one in a sealed, insulated crawlspace. All four builders emphasized 

the importance of using ACCA Manual J and S calculations to right 

Pine Mountain Builders used R-3 XPS 

rigid foam sheathing, a moisture-resistant 

alternative to OSB that also provides 

insulation value and stops thermal bridging 

in framed walls. The Georgia builder insulated 

wall cavities with an additional R-13 

low-density spray foam. (Photo Source: 

Pine Mountain Builders)

5.3

CHAPTER 5. THE MIXED-HUMID CLIMATE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 5.3
size the HVAC equipment—one installs high-efficiency gas furnaces, 

another high-efficiency propane furnaces, and two install highefficiency heat pumps. All four builders met ENERGY STAR Version 

2.0 criteria, and every home was third-party tested. 

Climate Description – Mixed-Humid

The mixed-humid climate is defined as a region that receives more than 

20 inches (50 cm) of annual precipitation, has approximately 5,400 

heating degree days (65°F basis) or fewer, and where the average monthly 

outdoor temperature drops below 45°F (7°C) during the winter months.

The Building America mixed-humid climate corresponds to climate 

zones designated 4 (non-marine) and 3 in category A above the warmhumid line on the International Energy Conservation Code (IECC) 

map (DOE 2010).

1

2 2

2 3

3

4

4

5 5

6

6

7

Marine (C)

Dry (B) Moist (A)

All of Alaska in Zone 7

except for the following

Boroughs in Zone 8:

Bethel

Dellingham

Fairbanks N. Star

Nome

North Slope

Northwest Arctic

Southeast Fairbanks

Wade Hampton

Yukon−Koyukuk

Zone 1 includes

Hawaii, Guam,

Puerto Rico,

and the Virgin Islands

Warm−Humid

Below White Line

Building America U.S. 

Climate Regions

International Energy 

Conservation Code Map

For More Information 

on Climate Description 

Briggs, RS; RG Lucas; and ZT Taylor. 2003. 

“Climate Classification for Building Energy 

Codes and Standards: Part 2 - Zone Definitions, 

Maps and Comparisons,” ASHRAE Winter 

Meeting, Chicago, January 2003 prepared for 

DOE by Pacific Northwest National Laboratory.

DOE. 2010. Vol. 7.1: Guide to Determining 

Climate Regions by County. PNNL-19517, 

Building America Best Practices Series, 

Prepared for the U.S. Department of Energy 

by Pacific Northwest National Laboratory, 

www.buildingamerica.gov

NOAA. 2010. National Climatic Data Center. 

www.climate.gov/#dataServices/pastPresent

HOT-HUMID

MIXED-HUMID

COLD / VERY COLD

HOT-DRY / MIXED-DRY

MARINE

Hawaii, Guam, Puerto Rico, 

and the U.S. Virgin Islands are 

all in the hot-humid climate.

CHAPTER 5 / BUILDING AMERICA BEST PRACTICES SERIES

5.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Weather

Portions of the mixed-humid climate zones are subject to frequent 

and intense rain storms, severe thunderstorms, and hail. Some areas 

are at high risk for tornadoes and high winds. Large portions of the 

Midwest and the South have been subject to flooding.

The mixed-humid climate is subject to hurricanes along the Eastern 

seaboard. The region is at low risk of earthquakes except for 

localized areas around Arkansas and South Carolina (USGS 2010).

Precipitation in the mixed-humid climate varies widely, from 20 

inches in the drier parts of Kansas, Oklahoma, and Texas, to more 

than 50 inches in Tennessee and North Carolina. Construction 

techniques for moisture management are described in Chapter 8. 

Flooding

Flooding is a concern along the coast and inland waterways of the 

mixed-humid climate. Large portions of the Midwest and South 

have been subject to flooding, with most of the counties of these 

areas experiencing four or more presidential disaster declarations 

due to flooding since 1965. 

Builders should check state building codes and contact the local 

community floodplain administrator for information on local floodplain 

management regulations. Location-specific Flood Insurance Rate Maps 

(FIRMs) can be obtained at www.fema.gov/hazard/map/firm.shtm.

If a community adopts and enforces adequate floodplain 

management regulations, FEMA will make flood insurance available 

within the community. Title 44 of the U.S. Code of Federal 

Regulations (CFR) contains the National Flood Insurance Program 

(NFIP) criteria for floodplain management, including design and 

construction standards for new and substantially improved buildings 

located in special flood hazard areas (SFHAs) identified on the 

NFIP’s FIRMs. An SFHA is an area that has a 1% chance of being 

flooded in a given year. [CFR Title 44, Section 60.3(a)(3) requires 

that all new construction in a flood-prone area be constructed with 

materials resistant to flood damage.] The lowest floor of a residential 

building must be elevated to or above the base flood elevation (BFE). 

All construction below the BFE is susceptible to flooding and must 

consist of flood damage-resistant building materials, for example 

brick; cement board; concrete; non-paper faced gypsum; steel or 

solid-wood preservative-treated studs, trusses, and joists; 

and ceramic tile. 

Mississippi River

Mississippi River

Missouri

River

Missouri

River

Rio Grande

Rio

Grande

Arkansas

River

Colorado

River

Ohio

River

Red

River

Brazos River

Columbia

River

Snake

R

Platte

R

Pecos River

Canadian

River

Tennessee

River

Colorado

River

Alabama

R

Kansas River

Republican

R

Lake of the

 Woods

Great

Salt

Lake

Lake

Okeechobee

Lake Pontchartrain

Lake

Champlain

Lake St Clair

Red

Lake

Salton Sea

Rainy

Lake

Lake Winnebago

Mille Lacs Lake

Yellowston e R

R Gila

River

N Platte R

S Platte

R

James

River

Red R

Illinois R

River

Cumberland

Savannah R

St Johns R

James R

Susquehanna

R

Connecticut R

Sacramento R

Green

Kennebec R

Hudson River

Scioto R

Wabash River

Oconee R

Des Moines R

Humboldt R

Willamette R

G U L F O F M E X I C O

P A C I F I C O C E A N

A T L A N T I C O C E A N

Lake Superior

Lake Michigan

Lake Huron

La k e Eri e

O n t a ri o

La k e

MAINE

VERMONT

NEW HAMPSHIRE

NEW YORK MASSACHUSETTS

CONNECTICUT

RHODE ISLAND

PENNSYLVANIA

NEW JERSEY

DELAWARE

MARYLAND

VIRGINIA

WEST

VIRGINIA

OHIO

INDIANA ILLINOIS

WISCONSIN

KENTUCKY

TENNESSEE NORTH CAROLINA

SOUTH

CAROLINA GEORGIA ALABAMA

FLORIDA

MISSISSIPPI

LOUISIANA

TEXAS

ARKANSAS

MISSOURI

IOWA

MINNESOTA

NORTH DAKOTA

SOUTH DAKOTA

NEBRASKA

KANSAS

OKLAHOMA

NEW MEXICO

COLORADO

WYOMING

MONTANA

IDAHO

UTAH

ARIZONA

NEVADA

CALIFORNIA

OREGON

WASHINGTON

DC

M I C H I G A N

The National Atlas of the United States of America U.S. Department of the Interior

U.S. Geological Survey

Where We Are nationalatlas.gov TM

OR

pageprecip_us3.pdf INTERIOR-GEOLOGICAL SURVEY, RESTON, VIRGINIA-2005

PACIFIC OCEAN

ATLANT I C O CE A N

HAWAII

ALASKA

M E X I C O

C A N A D A

C U B A

T H E B A H A M A

0 300 mi S

0 100 200 300 km

100 200

Albers equal area projection

PRECIPITATION

180.1-200

140.1-180

120.1-140

100.1-120

80.1-100

70.1-80

60.1-70

50.1-60

40.1-50

35.1-40

30.1-35

25.1-30

20.1-25

15.1-20

10.1-15

5.1-10

5 and less

Average Annual Precipitation (in inches)

1961-1990

Precipitation varies widely across the 

United States, from a low of 2.3 inches 

per year in California's Death Valley to a 

high of 460 inches on Hawaii's Mount 

Waialeale. Nevada ranks as the driest 

state, with an average annual 

precipitation of 9.5 inches, and Hawaii 

is the wettest, at 70.3 inches.

Average Annual Precipitation 

Average Annual Precipitation (1961-1990) (inches)

180.1 - 200

140.1 - 180

120.1 - 140

100.1 - 120

80.1 - 100

70.1 - 80

60.1 - 70

50.1 - 60 

40.1 - 50

35.1 - 40

30.1 - 35

25.1 - 30

20.5 - 25

15.1 - 20

10.1 - 15

5.1 - 10

5 and less

(Source: U.S. Geological Survey)

Severe Weather Reports 2010

(Source: National Weather Service)

wind

tornadoes

large hail

For More Information on 

Weather and Precipitation

National Climatic Data Center. 2005. Climate 

Maps of the United States. National Oceanic 

and Atmospheric Administration (NOAA) http://

hurricane.ncdc.noaa.gov/cgi-bin/climaps/climaps.pl

NOAA. 2010. Normal Daily Mean Temperature, 

Degrees F. U.S. Department of Commerce, National 

Oceanic and Atmospheric Administration, www1.

ncdc.noaa.gov/pub/data/ccd-data/nrmavg.txt 

U.S. Geological Survey. 2005. “The National 

Atlas of the United States of America: 

Precipitation,” U.S. Department of the Interior, 

www.nationalatlas.gov.

U.S. Geological Survey. 2010. “Natural 

Disasters,” www.usgs.gov/hazards/

5.5

CHAPTER 5. THE MIXED-HUMID CLIMATE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 5.5
Flood-resistant materials are described in “Flood Damage-Resistant 

Materials Requirements,” one of a series of Technical Bulletins that 

FEMA has produced to provide guidance concerning the building 

performance requirements of the NFIP (available at www.fema.gov/

plan/prevent/floodplain/techbul.shtm). [Code requirements for floodresistant construction are detailed in the 2009 IRC R322.]

In “Designing for Flood Levels Above the BFE” (FEMA 2009), 

FEMA noted that floods more severe than the base elevation flood, 

also known as the 100-year flood, do occur. For example in a 30-year 

period, there is a 14% chance that a 200-year flood will occur. 

FEMA reports that “up to 25% of NFIP flood insurance claims are 

paid on buildings that are outside of the mapped SFHA. This occurs 

for many reasons, including out-of-date maps and local drainage 

problems” (FEMA 2008). Therefore, all builders should be aware of 

flood-safe construction practices, regardless of location designation. 

FEMA (2009, 2011) and Building America (Lstiburek 2006) 

recommended that home builders do the following:

•	 Design homes on elevated foundations.

•	 Use strong connections between the foundation and the elevated 

building to prevent buildings from floating or washing off 

their foundations.

•	 Design drainable, dryable interior wall assemblies using non-watersensitive building materials such as masonry, spray foam, rigid 

fiberglass insulation, metal or pressure-treated lumber framing, 

and non-paper-faced gypsum, as shown in the figures below.

Portions of the mixed-humid climate 

region are prone to flooding, tornadoes, 

hail, and hurricanes. (Photo Source: USGS)

Constructing with moisture-resistant materials, such as brick or fiber-cement siding (left and middle) or masonry block (right) will 

limit moisture damage in exterior walls. (Figure Source: FEMA from Coastal Contractor Magazine and Building Science Corporation)

CHAPTER 5 / BUILDING AMERICA BEST PRACTICES SERIES

5.6 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
For More Information on Construction in Flood Zones

Algan, H. and Wendt, R. 2005. Pre-Standard Development for the Testing of Flood-DamageResistant Residential Envelope Systems, Oak Ridge National Laboratory.

FEMA. 2011. Home Builder’s Guide to Coastal Construction Technical Fact Sheets Series, 

Federal Emergency Management Agency, 

(www.fema.gov/rebuild/mat/mat_fema499.shtm) 

FEMA. 2009. FEMA 550: Recommended Residential Construction for the Gulf Coast: 

Building on Strong and Safe Foundations, Federal Emergency Management Agency, 

 (www.fema.gov/library/viewRecord.do?id=1853).

FEMA. 2009. Designing for Flood Levels Above the BFE. www.fema.gov/library/

file?type=publish edFile&file=757_apd_3designabovebfe_rev1.pdf&fileid=388b4fb0-34e6-

11de-baca-001185636a87

FEMA. 2008. Flood Damage-Resistant Materials Requirements for buildings located in 

special flood hazard areas in accordance with the National Flood Insurance Program, August 

2008, FEMA Technical Bulletin, Federal Emergency Management Agency, www.fema.gov/

library/viewRecord.do?id=1580

Lstiburek, Joseph. 2006. Flood and Hurricane Resistant Buildings, Building Science Digest 111, 

Building Science Press, www.buildingscience.com

Zoeller, William. 2006. Designing and Building Hurricane-Resistant Homes, Home Energy 

Magazine, Fall 2006, www.carb-swa.com/articles/in%20the%20news/HomeEnergy_

Designing%20and%20Building%20Hurricane%20Resistant%20Homes.pdf

Stormwater Management 

Builders are increasingly being called upon to manage surface runoff 

water onsite during and after construction because stormwater 

runoff carries with it sediment and pollutants that negatively impact 

water quality and high levels of runoff tax municipal sewer systems. 

Builders should check local requirements and guidelines regarding 

site water runoff control. For long-term stormwater management, 

builders can minimize impervious surface areas by designing smaller 

building footprints, clustering developments, and adding green space 

areas; installing onsite rain-water harvesting systems; and using 

pervious paver materials. Other recommendations include planting 

vegetated buffers around parking areas; planting new trees and 

shrubs and retaining existing trees to minimize erosion; constructing 

swales, drywells, soakage trenches, planter boxes, vegetated 

infiltration basins, and flow-through planters; and installing drywells 

under streets to handle overflow from large storm events. 

Tornadoes, Hurricanes, and High Winds 

Every state in the mixed-humid climate includes areas in wind zone 

4 (the highest risk zone on FEMA’s scale of four U.S. wind zones) or 

areas designated as special wind regions. The mixed-humid climate 

is vulnerable to catastrophic high-wind, heavy-rain events, such as 

tornadoes. Proper structural fastening and impact-resistant windows, 

doors, and skylights are critical to surviving high winds. Proper use 

For More Information About 

Stormwater Management

EPA. 2010. Stormwater Program. U.S. 

Environmental Protection Agency. http://cfpub.

epa.gov/npdes/home.cfm?program_id=6

City of Portland. 2010. Stormwater Solutions 

Handbook, Bureau of Environmental Services, 

www.portlandonline.com/bes/index.

cfm?c=43110

City of Cleveland. 2004. Guidance Document: 

Erosion and Sediment Control Best Management 

Practices for Home Builders, Cleveland, 

Tennessee.

(top) S&A Homes practices good water 

runoff management to control sediment 

during construction and to ensure that 

stormwater drains away from the house 

after construction.

(bottom) Vegetated swales, pervious pavers, 

pocket parks, and retention of existing 

trees all help to minimize runoff and lessen 

impacts on municipal sewer systems.

5.7

CHAPTER 5. THE MIXED-HUMID CLIMATE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 5.7
of roofing materials can help roofs withstand high winds and protect 

against severe rains. The following sources provide guidance for 

construction in high-wind areas.

The Federal Emergency Management Agency (FEMA), the National 

Association of Home Builders Research Center (NAHBRC), and 

the U.S. Department of Housing and Urban Development (HUD) 

have produced a series of 37 fact sheets for building homes in 

high-wind, high-rain coastal environments www.fema.gov/rebuild/

mat/mat_fema499.shtm). The guides cover siting recommendations; 

moisture barrier systems; housewrap, masonry, roof sheathing, and 

other building materials; door and window installation; roof and 

deck-to-wall flashing; tile and asphalt roofing techniques for high wind 

areas; foundations; and construction techniques in flood-prone areas. 

The Insurance Institute for Business and Home Safety provides 

structural details, guidance, and a list of building materials acceptable 

for hurricane, high-wind, floods and other natural disasters. The 

Institute also sponsors a Fortified for Safer Living program that 

certifies homes that meet a package of “code-plus” upgrades that 

greatly increase a new home’s resistance to natural perils, including 

hurricanes, tornadoes, wildfires, floods, freezing weather, hail and 

earthquakes, as well as fires and interior water damage (IBHS 2008). 

Insurance credits for certified homes are available in some states. See 

the Institute’s website for more details, www.disastersafety.org.

New requirements in the 2009 IRC R301 address some of these highwind concerns with increased wall bracing requirements for homes 

built in high-wind and high-seismic actvity areas. The code increases 

the amount of wall bracing needed to resist wind loads for threestory homes, homes with large open plans, and homes in high-wind 

regions. In addition, the code requires blocking between the roof 

framing members at braced wall panels for homes with deep truss 

members or roof joists, or homes in high-wind and high-seismic 

areas. The requirements include prescriptive blocking details for 

these conditions. These changes may require revisions to stock plans 

and standard detailing practices.

For builders and homeowners in tornado-prone areas, FEMA has 

prepared a guide for building safe rooms—rooms with reinforced 

walls where occupants can safely take shelter during a tornado or 

hurricane (FEMA 2011).

Wind Zones in the United States

Zone I (130 mph)

Zone II (160 mph)

Zone III (200 mph)

Zone IV (250 mph)

Wind Zones (Figure Source: 

FEMA 2008)

For More Information on 

Construction in Coastal 

and High Wind Areas

FEMA. 2011. “Safe Rooms,” Federal Emergency 

Management Agency, updated June 23, 2011, 

www.fema.gov/plan/prevent/saferoom/index.shtm

FEMA. Home Builder’s Guide to Coastal 

Construction. Federal Emergency Management 

Agency. www.fema.gov/library/viewRecord.

do?id=1570

IBHS. 2011. “FORTIFIED Communities of Scale,” 

Insurance Institute for Business 

and Home Safety, accessed 8-4-11,

www.disastersafety.org.

Institute for Business and Home Safety. 2008. 

Fortified for Safer Living Builders Guide, 2008 

Edition. www.ibhs.org.

CHAPTER 5 / BUILDING AMERICA BEST PRACTICES SERIES

5.8 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Considering Solar Gain 

in Siting and Design

Passive and active solar design elements can be incorporated into 

homes throughout the mixed-humid climate. Design considerations 

include lot orientation, roof tilt, overhangs, windows, and shading.

Even if the builder does not plan to put solar panels on the roof 

at initial construction, homes should be designed and sited with 

solar panels in mind so that homeowners can take advantage of this 

energy resource in the future. Significant amounts of unobstructed 

roof area are needed. Roof space that faces due south is ideal but 

not necessary. In the mixed-humid climate, the optimal tilt angle or 

roof pitch for solar panels is 30 degrees. However, more than 90% of 

the solar energy available can still be collected even when the panels 

face nearly due east to nearly due west at roof pitch angles of 0 to 60 

degrees (DOE 2007).

Lot Orientation 

Plan subdivision lot lines and roads 

for predominantly north and south 

orientation

N

N

Subdivision with

predominantly

north- and southfacing sites for 

higher solar panel 

exposure to sun

Typical Subdivision

S

p

n

f

h

e

N

For More Information 

on Solar Orientation

Christensen, C.B., and G.M. Barker. 2001. 

“Effects of Tilt and Azimuth on Annual 

Incident Solar Radiation for United States 

Locations,” NREL Report No. CP-550-32966, 

In Solar Engineering 2001: Proceedings of the 

International Solar Energy Conference, S.J. 

Kleis and C.E. Bingham (eds.). Presented at 

FORUM 2001, April 21–25, 2001, Washington, 

DC, The American Society of Mechanical 

Engineers (ASME), New York.

DOE. 2007. Building America Best Practices 

Series Volume 6. Solar Thermal and 

Photovoltaic Systems. Prepared for the U.S. 

Department of Energy Building America 

Program by Pacific Northwest National 

Laboratory. www.eere.energy.gov/buildings/ 

publications/pdfs/building_america/41085.pdf

Roberts, Bill. 2008. Solar Maps, produced by 

the National Renewable Energy Laboratory 

for the U.S. Department of Energy. 

www.nrel.gov/gis/solar.html

University of Oregon. Sun charts available free at 

http://solardat.uoregon.edu/SunChartProgram.html

Viera, R.K., K.G. Sheinkopf, and J.K. Stone. 

1992. Energy-Efficient Florida Home Building. 

3rd printing. Florida Solar Energy Center. 

FSEC-GP-33-88. Cocoa Beach, Florida.

42°

36°

30°

24°

Optimal Tilt Angles

In areas where the optimal tilt angle is 30 degrees, if the roof is facing due 

south, the tilt angle (roof pitch) can actually vary from 0 degrees to 60 degrees 

and the roof can still collect 90% to 100% of the available energy. If the roof pitch 

is at 30 degrees, the direction of the roof can actually vary about 65 degrees 

to the east or west and still gain 90% to 100% of the available sun energy 

(Christensen and Barker 2001).

-90 -60 -30 0

Azimuth

Optimal Tilt Angle of 42°

Optimal Tilt Angle of 36°

Optimal Tilt Angle of 30°

Optimal Tilt Angle of 24°

 Optimal Tilt Angle of 48°

 Optimal Tilt Angle of 18°

Tilt

0 30

30

60

90

60 90

-90 -60 -30 0

Azimuth

Tilt

0 30

30

60

90

60 90

-90 -60 -30 0

Azimuth

Tilt

0 30

30

60

90

60 90

Tilt

30

60

90

Tilt

30

60

90

30 0

Azimuth

Tilt

0 30

30

60

90

60 90

Percent of Solar 

Energy Available

50-60%

60-70%

70-80%

80-90%

90-100%

-90 -60 -30 0

Azimuth

Optimal Tilt Angle of 42°

Optimal Tilt Angle of 36°

ALASKA - Optimal Tilt Angle of 48°

Tilt

0

30

30

60

90

60 90

-90 -60 -30 0

Azimuth

Tilt

0

30

30

60

90

60 90

0.5 - 0.6

0.6 - 0.7

0.7 - 0.8

0.8 - 0.9

0.9 - 1.0

-90 -60 -30 0

Azimuth

Tilt

0

30

30

60

90

60 90

5.9

CHAPTER 5. THE MIXED-HUMID CLIMATE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 5.9
Overhangs

When positioning buildings to get the maximum passive solar 

benefit, overhangs can help manage heat gain and glare. Roofs 

should be designed with overhangs and porches to shade windows 

and doors. Overhangs also provide protection from rain, hail, and 

the effects of overheating and ultraviolet radiation on siding and 

windows. Overhangs may take the form of eaves, porches, awnings, 

pergolas, or trellises. Overhangs should be sized to account for 

differences in sun angles, elevation, window height and width, wall 

height above the window, and amount of shading desired based on 

time of day and time of year. 

Free and low-cost computer programs are available for sizing 

overhangs based on location. A free program telling you the 

angle of the sun for any point in the country is available at 

www.susdesign.com/sunangle/. Latitude, longitude, and elevation 

data can be obtained at www.wunderground.com/calculators/solar.

html. Optimal overhang dimensions can be calculated at 

www.susdesign.com/overhang/index.php. 

For example in Wichita, Kansas, a 3-ft high by 4-ft wide window 

positioned 2 feet below the overhang would need an overhang 

extending 1 foot to provide full shade at mid-summer at 2 pm.

U.S. Solar Resource

This map shows an annual average of the kilowatt hours per day of solar energy 

available per square meter across the United States. As shown on the map, the 

mixed-humid climate has 5 or more kWh/m2/day of solar resource available. 

(Figure Source: Roberts 2008)

Winter

Sun

Summer

Sun

24o

4 ft. 

63o

Sun angles vary by latitude

Winter

Sun

Summer

Sun

25o

4 ft. 

69o

Winter

Sun

Summer

Sun

25o

4 ft. 

65o

Louisville, 

Kentucky

Wilmington, 

Delaware

Wichita, 

Kansas

Sun angles vary by latitude, season, 

and time of day. Sun angles shown here 

are calculated for noon on June 21 and 

December 21. (Source: Sustainable by 

Design, www.susdesugn.com/sunangle)

CHAPTER 5 / BUILDING AMERICA BEST PRACTICES SERIES

5.10 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Pine Mountain Builders retained original 

native trees to provide shade and erosion 

control on home sites at its Longleaf 

Community at Callaway Gardens in Georgia. 

(Photo Source: Pine Mountain Builders)

Windows

Windows should be selected to manage the quantity of heat loss 

and solar gain, which are indicated by the U-value solar heat gain 

coefficient (SHGC). The U-value is a measure of heat transfer. The 

lower the U-value, the better the window performs at stopping heat 

flow. The SHGC measures how well the window blocks heat caused 

by sunlight. The lower the rating, the less solar heat the window 

transmits. The 2009 IECC Table 402.1.1 requires a window U-factor 

of ≤0.50 in IECC climate zone 3 (or ≤ 0.65 for impact-rated glass 

complying with IRC 2009 R301.2.1.2) and 0.35 for IECC climate zone 4. 

The maximum skylight U-factor requirement in 2009 IECC Table 

402.1.1 is 0.65 in IECC climate zone 3 and 0.60 in IECC climate zone 

4. The 2009 IECC Table 402.1.1 requires a maximum SHGC of 0.30 in 

IECC climate zone 3 and no requirement is given for IECC climate 

zone 4. For more information about windows including 2012 IECC 

requirements, see Chapter 8 of this guide and also see the Efficient 

Windows, Collaborative website at www.efficientwindows.org.

Shading 

Shade can be provided by intentional planting or preservation of existing 

trees on the site. Tree preservation increases salability. Native trees 

are the most beneficial to the environment. The NAHB reports in its 

survey of buyers, What 21st Century Home Buyers Want, that over 80% 

of respondents in the West rated trees as essential or desirable (NAHB 

2002). American Forests and the NAHB (1995) found that mature trees 

may add from $3,000 to $15,000 to the value of a residential lot.

Truly cool neighborhoods have trees. A study in Florida has 

shown that a subdivision with mature trees had cooler outside air 

with less wind velocity than a nearby development without trees 

(Sonne and Viera 2000). The development with a tree canopy had 

peak afternoon temperatures during July that were 1.1°F to 3.1°F 

(± 0.7°F) cooler than the site without trees. The total effect of 

shading—lower summer air temperature and reduced wind speed—

can reduce cooling costs by 5% to 10% (McPherson et al. 1994). 

Trees reduce cooling requirements, particularly when located on the 

south, east and west side of the home to block low-angle, morning 

and late-afternoon, peak solar-gain sun. Medium and large trees 

should be planted 16 to 22 feet from the side of the house, smaller 

trees can be planted 10 to 16 feet from the side of the house. (MiamiDade County. 2010. “Cool Your Home” www.miamidade.gov/derm/

tips_cool_your_home.asp). Trees more than 35 feet from the structure 

are too far away to provide shade. Planting trees that provide shade to 

your air conditioning compressor unit will help it work more efficiently.

Careful landscaping can 

preserve roof-top solar 

exposure and provide shading 

to help control solar gain 

through windows.

Large deciduous shade trees on the 

south and west sides of the home 

provide welcome relief from summer 

afternoon sun while allowing desirable 

winter sun to warm the house. 

(Figure Source: Viera et al. 1992)

5.11

CHAPTER 5. THE MIXED-HUMID CLIMATE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 5.11
Care should be taken not to shade roof-mounted solar equipment 

(e.g., photovoltaic panels and solar thermal water heating panels) 

or areas of the roof that could be reserved for future solar 

installations. A simple rule of thumb is that any potential shading 

structure should be twice as far away from the solar equipment as 

the structure is tall. Sun charts and digital tools are available to 

assess how obstructions such as trees, buildings, or chimneys will fall 

between the solar panel and the sun at various times of the year.

Established trees can also provide a ground-stabilizing force in areas 

with sloped lots that may be at higher risk of erosion and mud slides.

For More Information on Shading

American Forests and the National Association of Homebuilders. 1995. Building Greener 

Neighborhoods: Trees as Part of the Plan. NAHB, Washington, D.C. 

www.nahb.org/product_details.aspx?forsaleID=26

McPherson, G.E., D.J. Nowak, and R.A. Rowntree (eds). 1994. Chicago’s Urban Forest 

Ecosystem: Results of the Chicago Urban Forest Climate Project. U.S. Department of 

Agriculture, Forest Service, Northeastern Research Station, 

www.treesearch.fs.fed.us/pubs/4285

National Association of Home Builders. 2002. What 21st Century Homebuyers Want: 

A Survey of Customer Preferences, National Association of Home Builders, 

www.BuilderBooks.com

Parker, D., Sonne, J., and J. Sherwin. 2002. “Comparative Evaluation of the Impact of 

Roofing Systems on Residential Cooling Energy Demand in Florida,” Prepared by the 

Florida Solar Energy Center, In Proceedings of ACEEE 2002 Summer Study, American 

Council for an Energy Efficient Economy, Washington, DC, August 2002. 

www.fsec.ucf.edu/en/publications/html/FSEC-CR-1220-00/index.htm

Sonne, J.K. and R.K. Viera. 2000. “Cool Neighborhoods: The Measurement of Small Scale 

Heat Islands.” Prepared by the Florida Solar Energy Center, In Proceedings of ACEEE 2000 

Summer Study, American Council for an Energy Efficient Economy, Washington, DC. 

www.fsec.ucf.edu/en/publications/html/FSEC-PF-363-01/

Walker, L. and S. Newman. 2009. Landscaping for Energy Conservation. No 7.225, 

Colorado State University Extension. www.ext.colostate.edu/pubs/garden/07225.html

Viera, RK, KG Sheinkopf, and JK Sonne. 1992. Energy-Efficient Florida Home Building, 

third printing. Florida Solar Energy Center, FSEC-GP-33-88, Cocoa Beach, Florida. 

Moss

In climates with high humidity, unwanted moss and algae can grow 

on roofs, especially on north- and east-facing surfaces, and can stain 

and damage most roofing types. To inhibit moss and algae growth, 

roofs must have sunlight and airflow, allowing them to dry properly. 

Options for inhibiting moss growth in heavily treed areas include 

using metal roofs, installing metallic zinc or copper strips along the 

roof just beneath the peak, or using copper-treated asphalt shingles. 

The better option from an environmental (and cost) standpoint is 

to allow adequate air and light to reach the roof by planting and 

trimming trees so that branches do not overhang the roof.

For houses with solar photovoltaic roof 

panels, any potential shading structure 

should be twice as far away from the 

photovoltaic array as it is tall (D = 2 * H)

D D

H

H

New roofs are not immune to moss, which 

can spread quickly under favorable conditions 

like constant shade and low roof pitch.

For More Information on Moss 

City of Portland. “Safe Roof Moss Control,” 

Portland Bureau of Environmental Services, 

City of Portland, Oregon, www.portlandonline.com/

BES/index.cfm?c=50367

CHAPTER 5 / BUILDING AMERICA BEST PRACTICES SERIES

5.12 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
This chapter introduces fundamental principles of building science, 

including the systems approach to house design. The dynamic 

forces that drive the movement of moisture, air flow, and heat 

in homes are described. This background information helps to 

explain the underpinnings of the best practices described in later 

chapters. In applying building science, the goal is to design and 

build houses that work within the bounds of natural forces, and in 

some cases to put these forces to work for occupant comfort and 

building efficiency.

The Systems Approach 

Building America takes a systems approach to home design 

recognizing that, as buildings become increasingly efficient, one must 

take into account the interactions of all of the home’s components 

and subassemblies, both to maximize performance and to avoid 

catastrophe. This “whole-house” approach recognizes that changes 

in one or a few components can dramatically change how other 

components perform, affecting overall building energy use, comfort, 

and durability.

Building Science Basics

The successful builder needs to understand all of the forces that 

affect a house and how these forces interact with each other and the 

home’s components. These forces include water, vapor, air flow, heat 

transfer, and occupants.

Chapter 6.

Building Science and 

the Systems Approach

“The energy-efficient features of 

these homes really begin to shine 

after the homeowners move in. 

Then, we hear them saying things 

like, ‘We love our new house; we 

can’t believe how comfortable it 

is; we can’t believe how low the 

utility bills are!”

Mike Guinan, co-owner, Pine Mountain 

Builders, Pine Mountain, Georgia

CHAPTER TOPICS

6.1 The Systems Approach

6.1 Building Science Basics

6.3 Water

6.3 Vapor

6.5 Air Flow

6.6 Heat Transfer

6.8 Occupants

6.1

CHAPTER 6. BUILDING SCIENCE AND THE SYSTEMS APPROACH

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 6.1
The Systems Approach 

to House Design

In a system-designed house all the 

parts are designed to work together 

for a healthy, durable home that 

minimizes builder callbacks while 

cutting energy, maintenance, and 

repair costs down the road.

A. Air Sealing: Helps maintain proper 

pressure balance in the home and 

stops stack effect, limiting drafts 

and keeping humidity, soil gases, 

and garage contaminants out of the 

house. It also creates a barrier to 

rodents and insects.

B. Well-Designed Moisture Barriers 

and Drainage: Avoids expensive 

structural damage and helps stop 

humidity, mold, and mildew.

C. Insulation: Holds comfortable 

temperatures in conditioned spaces 

and helps control noise.

D. Right-Sized and High-Efficiency 

HVAC Equipment: Costs less to 

install than bigger equipment, 

saves energy, and is designed to 

comfortably handle heating and 

cooling loads.

E. Ventilation: Exhaust fans 

remove moisture and pollutants. 

A controlled, filtered air intake 

ensures plenty of fresh air.

F. Sealed Combustion Appliances: 

Reduce moisture buildup and 

ensure the safe removal of 

combustion gases with sealed 

combustion appliances. 

G. Compact and Tightly Sealed 

Duct Runs: Short, straight duct 

runs in conditioned space yield 

better airflow with less chance 

for leaks and fewer contaminants 

like humidity and dust from 

attics or crawlspaces. Leaky 

ducts are a major contributor to 

mold problems. Multiple return 

air paths ensure balanced air 

pressure for less drafts and 

more balanced temperatures 

throughout the house. Ducts 

are in conditioned space.

H. Efficient Windows: Help to 

reduce heating and cooling 

loads. Window flashing protects 

against water leaks.

I. Overhangs: Provide shade, 

reduce cooling load, and direct 

water away from the house.

J. Properly Designed Crawlspaces 

and Attics: These and other nonconditioned spaces should either 

be within the conditioned building 

envelope or isolated from it by 

sealed air barriers and insulation.

CHAPTER 6 / BUILDING AMERICA BEST PRACTICES SERIES

6.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Water

Rainwater wants to flow down and will take the path of least resistance. 

To minimize mold and moisture damage in homes, builders must 

become experts in moisture-management techniques, learning how 

to guide rainwater off or out of the structure and how to incorporate 

redundant levels of moisture protection into the home’s building shell. 

Liquid moisture can also originate in the ground and flow upwards. 

This uptake is due to capillary action that is related to the adhesive 

properties of water. Water is attracted to other water. This is called 

cohesion. Water is also attracted to other materials. This is called 

adhesion. Capillary action allows water to climb up into seemingly 

solid materials through pores in the material. A capillary break is a 

non-permeable material that blocks the capillary flow of water from 

the ground. See Chapter 8 for more details.

Vapor

Water in its liquid state is not the only problem; water vapor can 

also be a source of damage. Water vapor causes problems when it is 

trapped within a building assembly, such as a wall cavity. When warm 

air touches a cold surface, the water vapor it carries can condense, 

turning into its liquid form, where it can cause damage to structural 

components. Condensation can also form in and on ductwork, 

especially when air conditioning cools duct surfaces that come in 

contact with humid air, such as in a vented attic or crawlspace.

Water vapor can travel via two means - air movement or vapor 

diffusion. Of the two, air movement is the far more likely means of 

vapor transport; research shows 30 times more water vapor is carried 

through walls by air flow than by diffusion. Warmer air carries 

more vapor than cold air. Wherever there are air leaks, vapor can be 

carried, for example into attics or wall cavities. Stopping air leaks by 

thoroughly air sealing the building envelope is an important step in 

limiting damage from water vapor.

Water vapor also can be carried by diffusion, which can force 

vapor through materials and into places it shouldn’t be, such as 

wall cavities. Differences in vapor pressure and temperature drive 

diffusion. Vapor diffusion moves moisture from areas of higher 

vapor pressure to areas of lower vapor pressure, and from areas of 

higher temperature to areas of lower temperature. One example is 

inward solar vapor drive, which can occur with “reservoir claddings” 

such as brick veneer or stucco, that absorb moisture, which is then 

driven inward by solar heat.

(top) When moisture is trapped inside 

walls, mold can grow unchecked, causing 

damage to the walls and health impacts 

for the occupants. (Photo source: EPA; 

photo by Terry Brennan)

(middle and bottom) This sprinkler was 

placed too close to the house’s foundation 

wall. Moisture seeped through the concrete 

block causing water stains and mold inside. 

(Photo source: EPA; photo by Terry Brennan)

6.3

CHAPTER 6. BUILDING SCIENCE AND THE SYSTEMS APPROACH

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 6.3
Vapor movement through a building component can be impeded by 

use of a vapor diffusion retarder. Some building scientists will use 

the terms vapor retarder and vapor barrier interchangeably. Some 

building scientists refer to vapor retarders as materials with 0.1 to 1.0 

perm and vapor barriers as materials with less than 0.1 permeability. 

The 2009 IRC uses the term vapor retarder to refer to all such 

materials. Code defines classes of vapor retarders based on their perm 

ratings (see table at left). Vapor retarder requirements were removed in 

the 2009 IECC; however, vapor retarder requirements are addressed in 

the 2009 IRC. 

The 2009 IRC R601.3 (2012 IRC R702.7) requires no vapor retarders 

in walls in IECC Climate Zones 1, 2, 3, and 4 (except Marine 4). 

Building scientists recommend against putting a vapor retarder in 

walls in the hot-humid and mixed-humid climates. 

Historically, code has encouraged the use of vapor retarders on the 

warm-in-winter side of the insulation (2006 IRC R318.1). In warm 

climates that would be on the exterior side of the thermal barrier; in 

cold climates, that would be on the interior side of the thermal barrier. 

In the mixed-humid climate, placement of the vapor retarder based on 

winter conditions might place the vapor retarder on the “wrong” side 

during the summer.

Since the 2006 IECC and IRC, code has exempted IECC Climate 

Zones 1 through 4 (which includes the hot-humid and mixed-humid 

climates) from the requirement to have a vapor retarder. Even in 

Climate Zones 5 through 8, the IRC does not require a Class I or II 

vapor retarder like polyethylene but permits the use of a Class III 

vapor retarder like latex paint if the wall cavity has a vented cladding 

or rigid foam sheathing, as defined in the 2009 IRC Table R601.3.1. 

Walls in the mixed-humid climate that are properly vented with an 

air gap and/or walls with insulated foam sheathing should not need a 

vapor retarder layer. Wall venting behind brick and stone veneers is 

especially important. Under the right conditions, energy from the sun 

can push vapor through wet brick with the force of a steam boiler. 

Ventilation spaces behind brick help to dissipate this vapor before 

it is injected into the framed cavity. The amount of ventilation gap 

depends on the cladding used—the gap should be 1 or more inches 

behind brick or stone veneer, 3/4 inch behind stucco, and 1/16 inch 

behind lap siding.

To prevent vapor-related moisture accumulation and damage in wall 

cavities, walls should not have a Class I vapor barrier installed on the 

interior side of the wall’s thermal boundary and should not have vinyl 

wall coverings installed on the home’s interior wall surfaces.

Perm Ratings of Common 

Sheathing Materials

A perm is a measure of the permeability of a 

material. It indicates how much water vapor 

can pass through a material over a fixed 

period of time; the higher the number, the 

more easily water vapor can pass through.

Plywood sheathing More than 

1.0 perm 

OSB More than 

1.0 perm 

Exterior gypsum More than 

1.0 perm 

Fiberboard sheathing More than 

1.0 perm 

Extruded polystyrene 

foam sheathing 1 inch

1.0 perm 

or less

Expanded polystyrene 

rigid foam 1 inch

2 – 5 perms

Film-faced extruded 

polystyrene 0.5 inch thick 

with perforated facing 

More than 

1.0 perm 

Non-perforated foil-faced 

rigid insulation

Less than 

0.1 perm

Polypropylene-faced 

rigid insulation

Less than 

0.1 perm

Three-coat, hard-coat 

stucco over 2 layers of 

Type D asphalt-saturated 

Kraft paper and OSB

Less than 

1.0 perm

Source: Lstiburek 2006. See Building Science 

Corporation 2006 for an extensive list of 

building material perm ratings.

Vapor Retarder Definitions

The 2009 IRC R601.3 gives the following 

definitions and examples for vapor 

retarder classes:

Class Definition Examples

I ≤0.1 perm Sheet polyethylene, 

sheet metal, nonperforated aluminum foil

II >0.1 to 

<1.0 perm 

Kraft-faced 

fiberglass batts or 

low-perm paint

III >1.0 

perms 

Latex or enamel 

paint

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6.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Air Flow

Air enters a home through openings in walls, cracks around doors 

and windows, and at intersections of building assemblies. Key 

points of air entry include rim joists where foundations meet floors 

and walls, where walls and floors for upper stories join together, 

and where walls intersect the roof. The pressure difference between 

indoor and outdoor air (or between indoor air and soil gas), 

temperature differences, and wind are the driving forces of air 

infiltration. Plugging air leaks is one way to slow down infiltration.

Air movement can affect how well insulation works. When outside 

air is pushed through insulation in places such as attics, walls, or 

crawlspaces, it robs the insulation’s ability to slow down heat loss. 

This process is called wind wash or air intrusion. Using baffles, 

dams, and wind blocks in attics keeps ventilation ports open and 

directs air away from the insulation.

Controlled air movement in the right place is beneficial. Providing a 

ventilation space behind exterior wall cladding allows the material to 

dry out and prevents the moisture from contaminating housewraps, 

sheathing, or other wall components. 

Crawlspaces and attics are other areas in homes that have traditionally 

used passive ventilation to dissipate moisture. Researchers and builders 

have developed methods of building unvented, conditioned attics and 

crawlspaces, and sealing these areas may be recommended if they are 

to provide conditioned space to house HVAC equipment and ducts. 

(See Chapter 8 for more on crawlspaces.)

(left) Unintentional air leaks can allow 

leakage of significant amounts of air into 

and out of a home in an uncontrolled 

manner through unsealed seams and 

unplugged holes in the walls, ceiling, 

and floors. (Figure source: EPA)

(right) Urbane Homes of Louisville, 

Kentucky, uses XPS rigid foam instead of 

OSB for the sheathing on their homes’ 

exterior walls. The sheathing (shown here 

from inside the house) was taped at the 

seams and covered with housewrap.

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Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 6.5
Planned ventilation is needed to provide a healthy and comfortable 

indoor environment. Relying on air leakage to provide ventilation 

and combustion air is unreliable. By its nature, infiltration is not a 

reliable form of ventilation. It depends on pressure and temperature 

differentials that change constantly. Air leaks may also carry with them 

moisture that can cause structural or mold problems. Combustion 

in furnaces, fireplaces, dryers, and cooking appliances requires air. If 

multiple combustion or exhaust systems are drawing air at the same 

time and if these appliances are not all direct vented to the outdoors, 

there is a chance that combustion appliances can backdraft, drawing 

flue gases into a home rather than expelling them outdoors. Using 

supply ventilation provides make up air for combustion appliances and 

maintains the interior of the home at a slight positive air pressure with 

conditioned air that will also discourage the infiltration of hot humid 

air (Lstiburek 2005). Mechanical ventilation and sealed combustion 

systems are described in Chapter 9.

Heat Transfer

Heat travels via three mechanisms: conduction, convection, and radiation. 

Conduction

Conduction is the movement of heat through a material. It is the 

cause of a hot handle on a sauce pan simmering away on a range 

top. Heat flows from warm areas to cold areas. The larger the 

temperature difference between the areas the faster heat will flow. 

The ability of materials to resist heat flow influences conduction. 

Insulation is very good at resisting conducted heat flow. Dimensional 

lumber is not very good at resisting heat flow. The best way to 

slow down conduction is to add insulation to building envelope 

assemblies. It is important that insulation be installed to fill all voids 

in the building envelope. It is easier to fill voids using blown-in or 

sprayfoam insulation than with batt insulation. Blown cellulose or 

fiberglass insulation for example flows almost like a liquid, filling 

in areas behind wiring and framing where batt insulation might be 

compressed or blocked. Spray foam is applied as a liquid and also 

fills voids that may be difficult to reach with batts. Batts work well 

in large, uninterrupted areas if installed properly. 

The rate at which heat flows through a material is described using 

two terms: R-value and U-value. Resistance to heat flow is called 

R-value, the higher the R-value the more resistant a material is to 

heat conduction. R-values can be added together to calculate how 

well an entire assembly will resist heat flow. 

Conduction

Heat transferred by contact, like the hot 

pan that fries an egg or the hot asphalt 

that burns bare feet.

Convection

Heat transferred via air 

or liquid movement in 

a pattern of cooling/

falling and warming/

rising like hot water 

that rises and falls 

in a percolating 

coffee pot.

Radiation

Heat transferred through 

space by rays, like rays 

of sun that warm your 

skin if the rays 

are not blocked by 

a building or tree.

Stack Effect

The stack effect is the flow of air that 

results from warm air rising, creating a 

positive pressure area at the top of a 

building and a negative pressure area at 

the bottom of a building. The stack effect 

can overpower the mechanical system 

and disrupt ventilation and circulation 

in a building. It pulls unfiltered air and 

soil gases into a home through cracks 

in the foundation and around doors and 

windows and it draws conditioned air up 

and out through air leaks around ceilings, 

chimneys, flue, and pipe chases.

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6.6 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Conductivity is described using U-value. Conductivity refers to 

how well a material or assembly conducts heat. It is inversely 

proportional to R-value. If the U-value is high, then the R-value 

is low. From an energy-efficiency perspective, high R-values and 

low U-values are good. U-values may be calculated for an entire 

assembly or for an individual component. However, U-values for a 

number of components cannot be added together to calculate the 

overall U-value for an assembly such as a wall.

Convection

Convection is the movement of heat via a gas or liquid. Warm air 

becomes buoyant, while cold air tends to sink. Convection is the force that 

draws hot air up a chimney. This force is sometimes called the stack effect. 

Designers and builders can use convection as a natural way to cool 

and ventilate a home, but it can cause problems in the wrong places 

and circumstances.

In cooler climates, heated air tends to rise to the top of tall structures. 

Warmer air becomes buoyant and can carry more moisture than 

cool air. Near cold surfaces, such as inefficient windows, cooler air 

drops. As the air cools below the dew point, it must give up some of 

its moisture, which then condenses on the cold surface. This is why 

windows sometimes have condensation in wintertime.

In the summer, air-conditioned structures, colder air sinks, drawing 

in warmer air through leaks in the building envelope. Warmer air 

carries more moisture than cold air; as it cools, this moisture may 

condense inside structural assemblies. This outside air can also 

increase indoor humidity levels, causing occupants to turn up the air 

conditioner, which exacerbates the problem. 

Convective air currents can set up wherever differences in air pressure 

drive air movement. This applies to the house as a whole, and to 

smaller spaces. Convective loops can occur in cavities inside walls 

where there are voids in insulation, in attics, and even between tightfitting blinds and inefficient windows. Differences in temperature 

between the conditioned space and outdoors can create enough of a 

pressure difference inside a wall cavity to form a convective loop.

The most effective strategies for stemming convective heat losses are 

to avoid air temperature differentials inside structures, to fully fill 

insulated cavities with insulation (no voids), and to seal air leaks. 

Properly installing adequate insulation eliminates cold spots in walls 

and structural cavities. Sealing air leaks blocks air movement and 

minimizes the temperature differentials that occur when conditioned 

and unconditioned air mix.

Building America’s research team lead 

Building Science Corporation used 

convection to help cool this structural 

insulated panel (SIP) cottage in Georgia. 

Cool air from the screened porches is 

drawn into the building’s interior where 

it heats up and is pulled up and out the 

second-story windows, drawing more air 

in through the shaded first-story windows.

Living Room

Loft

Crawlspace

Screened 

Porch

Window

Screened 

Porch

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Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 6.7
Radiation

Radiation is the movement of heat by solar or infrared rays. 

For example, much of the heat from a woodstove is in the form 

of radiation. The key to radiation is that, unlike conduction or 

convection, this process does not involve a molecular connection 

between the source and the recipient of the heat. That is one reason 

a person sitting across the room feels toasty from a radiant heater, 

such as a woodstove. Heat can be transferred through a vacuum 

via radiation; this is how heat from the sun is transferred to Earth 

through the vacuum of space. 

Radiant heat can influence comfort. In a house with a reasonable 

indoor temperature, radiant heat from a hot window or wall can 

influence the comfort level of building occupants. In cold climates, 

heat radiating from occupants to a cold window or wall can make 

them feel colder. On the other hand, when indoor warming is 

needed, an occupant exposed to radiant floor heating may feel 

warmer than the air temperature suggests. 

Techniques for controlling solar radiation heat gain include tree 

shading and window awnings or overhangs. Radiant barriers installed 

in the attic and light-colored roofing material are used to minimize 

solar heat gain in the hot dry and hot humid climates but are not 

recommended in the heating-dominated areas of the cold climate. 

At night, a house can radiate heat to a clear night sky. The resulting 

cooling can lead to condensation in attics and roof wetting. 

Researchers are exploring ways to use radiation to the night sky 

as a passive way to cool homes.

Occupants

Occupants are a force unto themselves, not tied directly to climate or 

building dynamics but able to strongly influence building performance. 

Occupant comfort and costs are at the center of design considerations. 

However, as the building operators and maintainers, occupants can do 

much to correct or unbalance a system. Providing correct information 

in the form of owners manuals, homeowner education, and accurate 

marketing materials can help occupants make decisions that will 

contribute to their home’s longevity, comfort, and efficiency.

Occupants can have an enormous impact on the energy performance 

of their homes by the selections they make in appliances, 

entertainment systems, computers, tools, and other electric 

equipment. These plug loads make up about 40% of energy loads 

Occupant choices in appliances and home 

electronics have a big impact on plug load.

“A house is a really complicated 

set of systems and, as you start to 

build higher performing houses, 

the way in which those systems 

interact requires more detailed 

analysis. I would encourage 

others to take the time to do 

that analysis.” 

Will Bradshaw, President, 

Green Coast Enterprises, New Orleans

CHAPTER 6 / BUILDING AMERICA BEST PRACTICES SERIES

6.8 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
in homes. As builders and researchers figure out how to make 

thermal, lighting, and ventilation equipment more efficient, these 

miscellaneous plug loads will become more and more important in 

how energy is managed in homes.

More Information on Water, Vapor, Air Flow, 

and Heat Transfer

2009 IECC. 2009. International Energy Conservation Code, International Code Council (ICC), 

Washington, DC. www.iccsafe.org/Store/Pages

2009 IRC. 2009. International Residential Code - One and Two-Family Dwellings, Section 

408.3, “Unvented Crawl Spaces,” International Code Council (ICC), Washington, D.C. 

www.iccsafe.org/Store/Pages

ASTM E-2112-07. “Standard Practice for Installation of Exterior Windows, Doors and Skylights.” 

American Society for Testing and Materials (ASTM), www.astm.org/Standards/E2112.htm

ASTM E 2266. “Standard Guide for Design and Construction of Low-Rise Frame Building 

Wall Systems to Resist Water Intrusion.” American Society for Testing and Materials (ASTM), 

www.astm.org/Standards/E2266.htm 

Buildernews Magazine. May 2004. “Housewrap Felt or Paper: Comparing specs on weather 

barriers,” www.buildernewsmag.com/index.php?option=com_content&view=article&id=1168

%3AHousewrap+Felt+or+Paper%3A&Itemid=107

Building Science Corporation. Homeowner Information Resources. 

www.buildingscience.com/resources/more-topics/homeowner_resources

Building Science Corporation. 2006. Info-500: Building Materials Property Table, Building 

Science Corporation, April 16, 2010, www.buildingscience.com/documents/informationsheets/building-materials-property-table

Building Science Corporation. 2008. Info-310: Vapor Control Layer Recommendations, 

By Building Science Corporation, Sept. 8, 2009, www.buildingscience.com/documents/

information-sheets/3-water-management-and-vapor-control/info-sheet-310-vapor-controllayer-recommendations?topic=resources/more-topics/vapor_barrier_code_changes

DOE. 2000. “Technology Fact Sheet on Weather-Resistive Barriers.” U.S. Department of 

Energy, www.toolbase.org/PDF/DesignGuides/weatherresistantbarriers.pdf

DOE. 2009. “Residential Requirements of the 2009 International Energy Conservation 

Code,” PNNL-SA-65859, U.S. Department of Energy, Building Energy Codes Program, 

www.energycodes.gov/training/pdfs/2009_iecc_residential.pdf

EPA. 2009. Mold Course - Introduction to Mold and Mold Remediation for Environmental and 

Public Health Professionals. U.S. Environmental Protection Agency, accessed June 18, 2009, 

www.epa.gov/mold/index.html

Fenestration Manufacturers Association (FMA)/American Architectural Manufacturers 

Association (AAMA) 100-07. “Standard Practice for the Installation of Windows with 

Flanges or Mounting Fins in Wood Frame Construction.” Available from AAMA’s online 

store at www.aamanetstore.org/pubstore/ProductResults.asp?cat=0&src=100

HGTVpro.com. “Improved Stucco Systems.” Article available at www.hgtvpro.com/hpro/

bp_exterior_finishes/article/0,2617,HPRO_20149_4243887,00.html

IBACOS. 2002. “Moisture Issues in Homes with Brick Veneer.” IBACOS article available at 

www.eere.energy.gov/buildings/building_america/pdfs/db/36397.pdf

Lstiburek, Joseph W. 2005. Builders Guide to Mixed-Humid Climates, Energy & 

Environmental Building Alliance (EEBA), www.eeba.org/bookstore/prod-Builder_s_Guide_

to_Mixed_Humid_Climates-4.aspx

Lstiburek, Joseph W. 2001. “Brick, Stucco, Housewrap and Building Papers,” RR-0105, 

Building Science.com, www.buildingscience.com/documents/reports/rr-0105-brick-stuccohousewrap-and-building-paper/

6.9

CHAPTER 6. BUILDING SCIENCE AND THE SYSTEMS APPROACH

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 6.9
Lstiburek, Joseph W. 2003. EEBA Water Management Guide. Energy and Environmental 

Building Association. Minneapolis, Minnesota. www.eeba.org/bookstore/prod-Water_

Management_Guide-9.aspx 

Lstiburek, Joseph W. 2004. “Understanding Vapor Barriers,” ASHRAE Journal, 

August 2004. www.renewable-resource.net/resources/Understanding_Vapor_Barriers

Lstiburek, Joseph W. 2006. Building Science Digest 106: Understanding Vapor Barriers. 

Building Science Press. Waterford, Massachusetts. www.buildingscience.com/documents/

digests/bsd-106-understanding-vapor-barriers

Lstiburek, Joseph W. 2008. “Concrete Floor Problems,” BSI-003, Building Science Corporation, 

www.buildingscience.com/documents/insights/bsi-003-concrete-floor-problems. 

Parker, D., J. Sherwin, J. Sonne, N. Moyer. 2002. Comparative Evaluation of the Impact of 

Roofing Systems on Residential Cooling Energy Demand in Florida. Florida Solar Energy Center, 

FSEC-CR-1220-00, http://securedb.fsec.ucf.edu/pub/pub_show_detail?v_pub_id=4120

Straube, John. 2001. “Wrapping it Up,” Canadian Architect, May 2001. 

www.cdnarchitect.com/issues/ISarticle.asp?aid=1000115982

CHAPTER 6 / BUILDING AMERICA BEST PRACTICES SERIES

6.10 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
The building envelope is the boundary that separates interior 

comfort from exterior conditions. The envelope encompasses three 

boundaries: the thermal boundary, the pressure boundary, and 

the weather barrier.

•	 The thermal boundary consists of the building assemblies 

surrounding the space that is purposefully cooled or heated. 

The insulation plus the air barrier form the thermal boundary. 

•	 The pressure boundary is the point at which inside air and outside 

air are separated. The line where the pressure difference across 

the building shell is greatest between the inside and outside of the 

house is the pressure boundary. This boundary is where air sealing 

should occur. Thermal and pressure boundaries should be aligned. 

•	 The weather barrier includes screens to shed rain.

This chapter describes three strategies that apply to the overall building 

envelope: advanced framing, insulating, and air sealing. These strategies 

involve the entire house envelope and directly address the thermal and 

pressure boundaries. Specific practices that apply to particular assemblies, 

such as foundations, walls, and roofs, are described in the next chapter.

Advanced Framing

Optimal value engineering or advanced framing refers to framing 

techniques that require less lumber than standard framing practices 

but provide all the needed structural strength. Using less lumber 

leaves more room for insulation while saving resources and reducing 

waste. The recommendations below apply to framed walls using 

dimensional lumber. Other energy-efficient wall construction 

materials not described here include structural insulated panels, 

insulated concrete forms, and steel framing. 

Chapter 7.

The Overall 

Building Envelope

“Advanced framing is such a 

simple thing but very few builders 

are doing it. It is a selling point 

with customers. The performance 

characteristics are easy to point 

out to the customer and it’s 

easy to carry the energy-saving 

concepts through to other items 

like high-performance windows, 

more insulation, and air sealing.” 

Builder Barrett Burr, Olympia, Washington

CHAPTER TOPICS

7.1 Advanced Framing

7.5 Insulation

7.10 Air Sealing

7.12 ENERGY STAR Thermal 

Enclosure System Rater 

Checklist

7.1

CHAPTER 7. THE OVERALL BUILDING ENVELOPE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 7.1
In one Building America study, advanced framing resulted in 50% 

reductions in installation and materials costs along with a 7% increase 

in the amount of wall cavity area that could be insulated (PATH 2005). 

The simple measures taken in this project included single top plates, 

24-inch on-center 2x6 wall studs, and standardization of window and 

door openings to match the 24-inch layout. 

Building America research team lead Building Science Corporation 

helped David Weekley Homes implement advanced framing at its 

homes in Houston, Texas. Analysis by Building Science Corporation 

on one home model showed switching from 2x4 16-inch on-center 

to 2x6 24-inch on-center construction could reduce board feet by 

40% (from 5,186 ft to 3,082 ft) and cut costs by 40%, from $2,749 

to $1,632. In this analysis, the number of 8-ft studs was cut by 52% 

from 1,403 to 665.

While lumber savings are significant, there may be added costs 

for additional insulation, drywall clips and fastening hardware, 

and supervision time to train subcontractors. In hurricane-prone 

areas, talk to local code inspectors to determine approval before 

incorporating advanced framing techniques into your designs. See 

the advanced framing installer’s guide in Chapter 14 for more details 

on advanced framing and for a sample shear panel to strengthen 

foam-sheathed walls in hurricane-prone areas.

Advanced framing techniques will increase the amount of space in 

your wall for insulation and will decrease the amount of thermal 

bridging, but to eliminate thermal bridging completely in a framed 

wall, consider using rigid foam sheathing insulation, which is 

described in the next section.

(left) Sheet goods come in 4x8-foot 

dimensions. Designing and building on a 

2-foot grid saves cutting time and reduces 

lumber and sheet good waste. 

(right) Framing details include ladder 

blocking and two-stud corners. 

(Photo source: Tommy Williams Homes)

Advanced framing techniques include 

aligning wall studs with trusses and 

using single top plates.

ladder blocking 2-stud corners

CHAPTER 7 / BUILDING AMERICA BEST PRACTICES SERIES

7.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
A sample of advanced framing techniques includes the following:

•	 TWO-FOOT MODULE DESIGN. Starting with the foundation, 

the house exterior dimension footprint should be based on 

2-foot increments. Because sheet goods come in 4-foot by 8-foot 

dimensions, this reduces waste and cuts material costs. 

•	 FRAME 24-INCH ON-CENTER. Typical practice is to frame 

walls, floors, and often roofs at 16 inches on center. However, 

24-inch on-center walls are structurally adequate for most 

residential applications. Even though the stud size is increased 

from 2x4 to 2x6 on load-bearing walls, changing stud-spacing 

from 16 to 24 inches can reduce framing lumber needs significantly. 

Confirm with local building officials because some jurisdictions 

in high-wind areas may not allow 24-inch on-center construction 

(PATH 2005).

•	 ALIGN FRAMING MEMBERS AND USE A SINGLE TOP PLATE.

Double top plates are used to distribute loads from framing 

members that are not aligned above studs and joists. By aligning 

framing members vertically throughout the structure, the second 

plate can be eliminated. Plate sections are cleated together using flat 

plate connectors [2009 IRC R602.3.2].

•	 SIZE HEADERS FOR ACTUAL LOADING CONDITIONS.

Headers are often oversized for the structural work that they 

do. Doubled-up 2x6 headers end up in non-load-bearing walls. 

Doubled-up 2x12 headers end up in load-bearing walls, regardless 

of specific loading conditions. Nonbearing walls do not need 

structural headers [2009 IRC R602.7.2]. Proper sizing may allow 

for the use of insulated headers in which foam insulation is 

sandwiched between lumber.

•	 LADDER-BLOCK EXTERIOR WALL INTERSECTIONS.

Where interior partitions intersect exterior walls, three-stud “partition 

post” or stud-block-stud configurations are typically inserted. Except 

where expressly engineered, these are unnecessary. Partitions can be 

nailed either directly to a single exterior wall stud or to flat blocks 

inserted between studs. This technique, called “ladder blocking” or 

“ladder framing,” creates room for more insulation. 

Using single 2x4 headers instead of double 

2x6 headers in non-load-bearing walls 

allows space for insulation.

Ladder blocking where exterior walls 

intersect interior walls provides space for 

insulation and cuts back on thermal bridging.

Closed, insulated headers are one advanced 

framing technique. (Figure source: CARB)

Single top plate

Plywood sides 

with rigid insulation 

sandwiched inside

Plywood plate

2x4” 

header Maximum 8’ span

Insulate above 

headers

Max 2’ above 

header

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CHAPTER 7. THE OVERALL BUILDING ENVELOPE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 7.3
•	 USE TWO-STUD CORNERS. Exterior wall corners are typically 

framed with three studs. The third stud generally only provides 

a nailing edge for interior gypsum board and can be eliminated. 

Drywall clips, a 1x nailing strip, or a recycled plastic nailing 

strip can be used instead. Using drywall clips also reduces 

opportunities for drywall cracking and nail popping, frequent 

causes of builder callbacks.

•	 ELIMINATE REDUNDANT FLOOR JOISTS. Double floor 

joists are often installed unnecessarily below non-load-bearing 

partitions. Nailing directly to the subfloor provides adequate 

attachment and support. Partitions parallel to overhead floor or 

roof framing can be attached to 2x3 or 2x4 flat blocking. 

•	 USE 2X3s FOR PARTITIONS. Interior, non-load-bearing 

partition walls can be framed with 2x3s at 24 inches on center or 

2x4 “flat studs” at 16 inches on center [2009 IRC R602.5]. 

For More Information on Advanced Framing

DOE. 2002. Advanced Wall Framing. U.S. Department of Energy 

www.nrel.gov/docs/fy01osti/26449.pdf

DOE. 2009. Advanced Framing, Article 1399, U.S. Department of Energy Building Energy Codes 

Resource Center, http://resourcecenter.pnl.gov/cocoon/morf/ResourceCenter/article//1399

IBACOS. 2003. Best Practices: Optimum Value Engineering. Prepared for the U.S. 

Department of Energy, Building America Program, www.eere.energy.gov/buildings/

building_america/pdfs/db/35380.pdf

Lstiburek, Joseph. 2005. “The Future of Framing Is Here,” Fine Homebuilding, 

November 2005, No. 174, p. 50-55. www.finehomebuilding.com/PDF/Free/021174050.pdf

NAHBRC. 2008. “Advanced Framing Techniques: Optimum Value Engineering (OVE),” 

National Association of Homebuilders Resource Center, accessed June 4, 2008, 

www.toolbase.org/Construction-Methods/Wood-Framing/advance-framing-techniques

NRDC. 1998. Efficient Use of Wood in Residential Construction. Natural Resources Defense 

Council, Washington, D.C. www.nrdc.org/cities/building/rwoodus.asp

PATH. 2005. ToolBase Techspecs: Advanced Framing Techniques. 

www.toolbase.org/pdf/techinv/oveadvancedframingtechniques_techspec.pdf

Two-stud corners with drywall clips 

use the least wood and give the best 

thermal performance.

Conventional three-stud corner leaves 

a cavity that must be insulated by the 

framers—not good.

Improved three-stud corner allows 

insulation to be installed later, 

in sequence.

CHAPTER 7 / BUILDING AMERICA BEST PRACTICES SERIES

7.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Insulation

Insulation provides the thermal boundary in the home’s walls, ceiling, 

and foundation by blocking heat loss through conduction. Insulation 

comes in a variety of forms; some of the common options are described 

below. Average R-values are provided in the table. Vapor retarders 

are not recommended on the interior of wall assemblies in the 

hot- or mixed-humid climate (they can trap moisture inside the wall 

cavity). Therefore, kraft-faced or foil-faced insulation should not be 

used in framed or masonry walls in the mixed-humid climate.

Common Insulating Materials (R-values per inch of insulation)

INSULATING MATERIAL Avg. R-Value per 

Inch

Fiberglass • Unfaced batt, standard density R-2.9 to R-3.8

• Unfaced batt, high density R-3.7 to R-4.3

• Blown fiberglass R-2.2 to R-2.7

Expanded 

Polystyrene (EPS)

• Rigid foam board R-3 to R-4

• Beads R-2.3

Extruded 

Polystyrene (XPS) • Rigid foam board R-5

Polyisocyanurate • Rigid board R-5.6 to R-8

• With foil facing R-7.1 to R-8.7

Polyurethane • Spray foam or foam board R-7 to R-9

• Foam board with foil facing R-7.1 to R-8.7

• Soy-based polyurethane spray foam R-3.7

Other • Cellulose, blown R-3.6 to 3.8

• Mineral wool, rock or slag, 

batt or loose

R-3.7

• Cotton batt R-3.4

• Sheep’s wool batt R-3.5

• Strawbale R-2.4

• Plastic PET R-3.8 to R-4.3

Source: DOE Energy Savers website: www.energysavers.gov/your_home/

insulation_airsealing/index.cfm/mytopic=11510

BLANKETS OR BATTS: Blanket insulation in the form of batts 

or rolls is a flexible product made from mineral fibers, fiberglass, or 

textile fibers. Batts are available in widths suited to standard wall, 

floor, and attic framing spaces. Continuous rolls can be hand-cut and 

trimmed to fit. Proper installation (where the batt fills the full cavity 

(1) Batt insulation in ceiling. (2) Blownin insulation. (3) Spray foam. (4) Spray 

foam applied along the underside of the 

roof deck to provide a conditioned and 

non-vented attic space for ducts and air 

handlers.

7.5

CHAPTER 7. THE OVERALL BUILDING ENVELOPE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 7.5
with no sagging, pinching or gaps) is key to getting full R-value 

from the batts. Standard fiberglass batt insulation features R-values 

between R-11 (3.5-inch thick) and R-38 (12-inch thick). Highperformance (medium- and high-density) fiberglass batts with greater 

R-values per inch of thickness are also available. If you choose to 

use other types of insulation, such as blown-in, batts can be installed 

in areas that may become inaccessible as construction unfolds; for 

example behind shower inserts, beneath stairs, or in rim joists. Batts 

also make good dams in attics around access points or other areas 

where blown-in insulation should be held back. Batts are not air 

barriers. They are available with or without vapor retarder facings. 

Kraft facing forms a Class II vapor retarder. If batts are used for wall 

insulation in the mixed-humid climate, they should be unfaced. 

BLOWN-IN: Blown-in, loose-fill insulation includes loose fibers or 

beads that are blown into building cavities or attics using special 

pneumatic equipment. Netting may be stapled to studs to hold 

blown-in insulation in place before gypsum board is installed. 

Another form of blown-in insulation is fibers, such as cellulose 

made from recycled newspaper, that is mixed with a wet adhesive 

and sprayed into the wall cavity, then allowed to set in the walls 

making it resistant to settling. An advantage of blown-in insulation 

is that it easily takes the form of the cavity into which it is blown. 

Blown-in insulation will also fill spaces behind and around potential 

obstacles, such as electrical boxes, wiring, and plumbing. The 

blown-in material can provide some resistance to air infiltration if 

the insulation is sufficiently dense, but blown-in insulation should 

not be considered an air barrier.

SPRAY POLYURETHANE FOAM (SPF): Foamed-in-place 

polyurethane foam insulation can be applied by a professional 

applicator using special equipment to meter, mix, and spray the 

insulation into cavities where the foam hardens in place. Some 

polyurethane foams are made with up to 20% soy-based oil stock 

rather than 100% hydrocarbon-based oil. Sprayed foam makes an 

excellent air seal and can be used to reach hard-to-get-at places. 

Critical points where this type of foam is especially useful include 

complicated intersections of building elements with odd shapes 

and many joints. Other common areas include the rim joists at the 

intersection of the foundation and floor and between floors.

Spray foam comes with either an open-cell (OC SPF) or closed-cell 

(CC SPF) structure. An open-cell structure allows air to move between 

the cells within the insulation; water may be used as the blowing agent. 

Closed-cell foam is more rigid and dense with each cell forming a 

bubble that captures the gas inside of it. Closed-cell foam contains 

special gases that make it expand and give it greater R-values. 

Open-cell foam is less dense, has a lower R-value rating, and is 

(top) Masonry walls can be insulated with

rigid foam insulation on the interior (shown 

here) or exterior.

(bottom) Sealing gaps between floor joists 

with spray foam provides a good air seal 

that prevents the flow of heat, cold, and 

pollutants from unconditioned space to 

conditioned space.

CHAPTER 7 / BUILDING AMERICA BEST PRACTICES SERIES

7.6 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
generally less expensive. Both types of foam are excellent air sealers. 

High-density, closed-cell foams have greater resistance to bulk liquid 

and vapor and may serve as both air and vapor barriers. Spray foam 

companies have converted to using a non-ozone-depleting blowing 

agent, but these agents may still have global warming potential.

RIGID FOAM INSULATION: Rigid insulation is made from fibrous 

materials or plastic foams that are pressed or extruded into sheets 

and molded pipe coverings. Rigid insulation provides thermal and 

acoustical insulation, strength with low weight, and coverage with few 

heat loss paths. Rigid foam insulating sheathing has other significant 

benefits, particularly in the areas of moisture control. Inwardly driven 

moisture from reservoir claddings such as brick and stucco can be 

controlled by rigid foam insulating sheathing. Code permits the use of 

exterior rigid foam insulating sheathing [2009 IRC 601.3]. If sufficiently 

braced, walls can use rigid foam as an insulating sheathing in place of 

oriented strand board (OSB) and plywood sheathings for cost savings.

Rigid foam insulation sheets may be faced with a reflective foil that 

reduces radiant heat transfer when facing an air space. Foil facing 

also makes the board nearly impervious to water and vapor, so it 

should be used with caution. Rigid foam insulation may be used in 

combination with other insulation types, such as on the exterior of 

walls whose cavities are filled with cellulose or fiberglass. Foam sheets 

that may be in contact with the ground should be borate-treated for 

termite resistance. Rigid fiberglass insulation is used on the exterior of 

basement or foundation walls and can form a moisture screen. 

Rigid insulation sheets may be applied to the exterior of wall 

assemblies as insulating sheathing. This approach helps to seal air 

leaks, block thermal bridges where framing lumber spans the wall, 

provide a drainage plane or rain screen, and create additional R-value 

near the exterior surface of the wall. Insulation on the outside of 

the wall helps to temper the wall’s interior temperature and avoid 

condensation. Here is a summary of rigid insulation materials:

•	 Polyisocyanurate – 5.6 to 8.7 R-value per inch

Typically foil-faced rigid sheet; it should not be used in contact 

with soil because it absorbs moisture. The foil facing is a vapor 

barrier so, in general, foil-faced insulation should not be used on 

the interior side of walls in the mixed-humid climate.

•	 Extruded Polystyrene (XPS) – 5 R-value per inch

More consistent density and greater compressive strength than 

EPS; preferred material for soil contact or as rain barrier because 

it is resistant to liquid moisture penetration. The EPA deadline 

to switch to a non-ozone-depleting, VOC-free blowing agent was 

January 1, 2010. 

Bob Ward Companies used an exterior wall 

sheathing consisting of a 1/8-inch layer of 

laminated fiberboard covered with 1-inch 

of extruded polystyrene foam board. This 

layer goes on the exterior side of the studs 

under the stone or wood siding. Joints 

are taped so the foam board serves as an 

air barrier as well, eliminating the need 

for housewrap. This exterior insulation 

layer moves the dew-point surface to the 

outside of the framing member, reducing 

the potential for condensation and 

moisture damage within the wall cavity. 

(Photo source: Bob Ward Companies)

7.7

CHAPTER 7. THE OVERALL BUILDING ENVELOPE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 7.7
•	 Expanded Polystyrene (EPS) – 2.3 to 4 R-value per inch

EPS foam beadboard uses a non-ozone-depleting blowing agent 

(pentane). Spaces between beads can absorb water. It is not a 

vapor retarder. It is often used in structural insulated panels and 

insulating concrete forms; comes with borate treatment making 

it resistant to insects; requires a capillary break between soil and 

insulation; and comes in many densities and grades. 

•	 Rigid Fiberglass – 2.2 to 4.3 R-value per inch

Drainable and resistant to insect degradation; excellent for soil contact.

REFLECTIVE INSULATION AND RADIANT BARRIERS:

Reflective insulation is fabricated from aluminum foil and comes 

with a variety of backings such as rigid polyisocyanurate foam, kraft 

paper, plastic film, polyethylene bubbles, or cardboard. It is also 

available as a roof sheathing product where the reflective surface 

comes pre-adhered to the OSB sheathing layer. Reflective insulation 

is used in attics, walls, and floors, usually in combination with other 

insulation products. Because it is a vapor barrier, it should not be 

used on the “cold side” (interior) of the thermal envelope in the 

mixed-humid climate, except as noted above in the description of 

polyisocyanurate. 

A common application in hot climates is the use of radiant barriers 

in attics to impede radiant heat transfer from the roof into the attic 

and the rooms below. The radiant barrier can be installed in one of 

three ways: stapled to the underside of the roof rafters, laid on top 

of the roof rafters before the roof sheathing is laid, or applied as 

part of an integrated reflective roof sheathing product. In all cases, 

the reflective “shiny” side faces down toward the ceiling and there 

most be an airspace below the radiant barrier for it to work properly. 

The radiant barrier should not be laid on top of ceiling insulation 

with the shiny side facing up as dust accumulation will soon inhibit 

its effectiveness. 

Studies show that radiant barriers can cut cooling costs between 8% 

and 12% in hot climates. The savings will be greatest if you have cooling 

equipment or duct work in the attic. For more on radiant barriers and 

their installation, see the radiant barriers primer by Building America 

research partner the Florida Solar Energy Center (FSEC 2005).

David Weekley Homes uses a radiant 

barrier product that comes adhered to 

the underside of the roof sheathing.

(Photo Source: David Weekley Homes)

CHAPTER 7 / BUILDING AMERICA BEST PRACTICES SERIES

7.8 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
For More Information on Insulation

ASHRAE. 2009. ASHRAE Handbook of Fundamentals. American Society of Heating, 

Refrigerating, and Air-Conditioning Engineers. www.ashrae.org/publications/page/158

Consortium for Advanced Residential Buildings. Steven Winter Associates (CARB-SWA). 

2009. Open-Cell vs Closed-Cell Foam Guide. www.carb-swa.com

ENERGY STAR. Builder Option Packages (BOPS) with recommended insulation levels 

by county. www.energystar.gov/index.cfm?c=bop.pt_bop_index

FSEC. 2005. Radiant Barriers: A Question and Answer Primer. Florida Solar Energy Center. 

www.fsec.ucf.edu/en/publications/html/FSEC-EN-15/

Krigger, John and Chris Dorsi. 2009. Resident Energy: Cost Savings and Comfort in Existing 

Buildings, 5th Edition, Prentice Hall (previous editions published by Saturn Resource Management).

Mathis, R.C. 2007. Insulating Guide. Building Science Press. Westford, MA. Available for 

purchase at www.eeba.org/bookstore/prod-Insulating-Guide-8.aspx

Parker, Danny and John Sherwin. 1998. “Comparative Summer Attic Thermal Performance 

of Six Roof Constructions.” TO-98-17-3. 1998 ASHRAE Annual Meeting, Toronto, Canada. 

www.fsec.ucf.edu/en/publications/pdf/FSEC-PF-337-98.pdf

Parker, Danny. 2001. FPC Residential Monitoring Project: New Technology Development 

Radiant Barrier Pilot Project. FSEC-CR-1231-01. Florida Solar Energy Center, Cocoa, FL. 

www.radiantbarrierdoneright.com/FSEC.pdf

Roos, Carolyn. 2008. Principles of Heat Transfer. WSUEEP07-004. Washington State 

University, Extension Energy Program, Olympia, WA. www.energy.wsu.edu/pubs/

U.S Department of Energy (DOE). 2009. “Cool Down with ‘Reflective Insulation’ Materials.” 

Setting the Standard. January 2009. DOE Building Energy Codes Program, 

www.energycodes.gov/publications/STS/2009/standard_january09.pdf

U.S. Department of Energy. 2009. “Radiant Barriers,” updated May 28, 2009, 

www.energysavers.gov.

U.S. Department of Energy (DOE). 2008. Insulation Fact Sheet. DOE/CE-0180. DOE’s 

insulation calculator for recommended insulation levels. www.ornl.gov/sci/roofs+walls/

insulation/ins_16.html 

U.S. Department of Energy (DOE). 1991. Radiant Barrier Attic Fact Sheet. DOE/CE-0335P. 

www.ornl.gov/sci/roofs+walls/radiant/rb_01.html

U.S. Department of Energy (DOE). “Recommended insulation levels by zip code.“ 

www1.eere.energy.gov/consumer/tips/insulation.html

(top) Holes in the top plate for wiring are 

sealed with foam.

(middle) Unsealed holes for pipes can

leave large gaps for air and bugs to

pass through.

(bottom) Thorough air sealing and locating 

ducts in conditioned space are two ways 

the Loudon County Habitat for Humanity 

affiliate improves the efficiency of its homes. 

(Photo Source: Loudon County Habitat for 

Humanity)

7.9

CHAPTER 7. THE OVERALL BUILDING ENVELOPE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 7.9
Air Sealing

Unintentional air flow (through-wall penetrations, leaks around 

doors and windows, and cracks in the roof) robs a home of warm 

or cool air, serves as a pathway for moisture flow, and decreases 

comfort levels. Controlling air infiltration is one of the most 

cost-effective and simplest energy-efficiency measures in modern 

construction practices. Extensive air sealing is one of the primary 

40% improvement strategies. Air sealing is required by the 2009 

IECC 402.4, which identifies several areas for air sealing and requires 

verification with a blower-door test or visual inspection.

Good caulking and sealing will reduce the infiltration of dust and 

dirt (and even bugs) that can enter homes through cracks and holes. 

The materials and approaches recommended here are common and 

time tested. However, these measures must be carefully installed to be 

effective and must be installed in the proper construction sequence 

before cavity areas are covered up by fixtures or walls. Health and 

safety are essential factors to consider when air sealing, especially if 

the home contains combustion appliances. See Building America’s 

Air Sealing guide for more information (www.buildingamerica.gov). 

Sealing against air leakage is primarily done for thermal reasons, 

but when coupled with appropriate mechanical ventilation, this 

procedure also assists in maintaining good indoor air quality for the 

occupant. This combination helps to provide controlled air rather 

than relying on pressure and temperature differences to supply air. 

Air leaks also carry water vapor; if this water vapor condenses, it 

can cause mold and other moisture problems. An important job for 

air barrier systems is separating garages from conditioned spaces to 

keep pollutants out of the house. 

The key to the control of airflow is the use of a continuous air barrier. 

This barrier may be made up of several types of materials as long as 

it provides an unbroken barrier between conditioned space (indoors) 

and unconditioned space (outdoors, attic, crawlspace, and garage). 

Typically mudded and taped gypsum board serves as an air barrier 

on the home’s interior. Alternatively, stucco or taped and caulked 

rigid foam may serve as an air barrier on the home’s exterior.

Building America researchers have worked with three building 

approaches that push the air and thermal barriers toward the exterior 

of the building shell: 1) conditioning crawlspaces and basements 

or using slabs, 2) installing insulated exterior sheathing, with sealed 

seams, and 3) conditioning attics. These approaches make it easier 

to provide an uninterrupted air barrier (see Chapter 14). 

(top) Seams are caulked to provide a good air 

seal before installing insulation and dry wall.

(middle) Air sealing the wall between the 

garage and the home is vital for occupant 

health and safety.

(bottom) Framing is sequenced to install 

an air barrier of OSB, plywood, or rigid 

foam between the porch and the attic.

CHAPTER 7 / BUILDING AMERICA BEST PRACTICES SERIES

7.10 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
The installation of high-efficiency furnaces and water heaters can 

also help control air leakage. Natural gas-fired condensing furnaces 

achieve combustion efficiency levels greater than 90%. These directvent furnaces and water heaters are sealed combustion systems that 

intake and exhaust air through plastic pipes that do not require a 

vertical chimney. Chimneys and flue chases are notorious for air 

and thermal leaks. A direct-vent fireplace can also eliminate the 

need for a chimney entirely. Ducts located in conditioned space 

eliminate penetrations through the building shell and avoid the 

intake of unconditioned air that can occur through duct leaks. 

More information on these systems is included in Chapter 9.

ENERGY STAR Thermal Enclosure Checklist

As part of the qualifications for ENERGY STAR for Homes 

Version 3.0, ENERGY STAR has developed a new Thermal 

Enclosure System Rater Checklist that guides builders and raters 

through verification of several points in the home’s thermal 

boundary. These include windows, insulation, air barriers in walls, 

floors, and ceilings, reduced thermal bridging, and air sealing. The 

checklist can be seen on the following pages. See the ENERGY 

STAR website more information about this checklist and other 

criteria for ENERGY STAR for Homes Version 3.0, which will 

become effective for all new homes January 1, 2012.

For More Information on Air Sealing

2009 IECC. 2009. International Energy Conservation Code, Section 402.4 “Air Leakage,” 

International Code Council (ICC), Washington, DC. www.iccsafe.org/Store/Pages

DOE. 2010. Retrofit Techniques and Technologies: Air Sealing, PNNL-19284, U.S. Department 

of Energy, http://www1.eere.energy.gov/buildings/building_america/

ENERGY STAR. 2008. “Thermal Bypass Checklist” www.energystar.gov/ia/partners/bldrs_

lenders_raters/downloads/Thermal_Bypass_Inspection_Checklist.pdf

ENERGY STAR. 2008. “ENERGY STAR Qualified Homes: Thermal Bypass Checklist Guide,” 

ENERGY STAR. www.energystar.gov/ia/partners/bldrs_lenders_raters/downloads/TBC_

Guide_062507.pdf

ENERGY STAR. 2011. ENERGY STAR Qualified Homes, Version 3 (Rev. 04) National Program 

Requirements, www.energystar.gov/ia/partners/bldrs_lenders_raters/ES_Combined_Path_

v65_clean_508.pdf

Gunsch, K. 2010. “Hot-Humid Wash-N-Wear House,” Presented at Affordable Comfort Incorporated 

National Conference, 2010, Prepared by Building Science Corporation for the U.S. Department of 

Energy Building America program, www.buildingscienceconsulting.com/presentations/documents/

ACI%202010%20Hot%20Humid%20Wash%20N%20Wear%20House.pdf

Lstiburek, Joseph. 2006. Building Science Digest 104: Understanding Air Barriers. Building 

Science Press, Waterford, MA. Available at www.buildingscience.com/documents/digests/

bsd-104-understanding-air-barriers

Lstiburek, Joseph. 2010. Guide to Attic Air Sealing, prepared by Building Science 

Corporation for the U.S. Department of Energy Building America Program. 

www.buildingscience.com/documents/primers/Attic%20Airsealing%20Guide%20-%20

BSC%20Draft%20-%202010-02-12.pdf/view

(top) Pine Mountain Builders spray 

foams their unvented attics with R-30 

of low-density spray foam to provide a 

conditioned space for the high-efficiency 

heat pump and ducts. (Photo Source: 

IBACOS)

(bottom) Rigid foam wall sheathing is 

taped at seams and all holes are taped as 

well to provide a continuous air barrier. 

These measures help Imagine Homes 

achieve whole-house air leakage of 

less than 2.5 air changes per hour at 50 

Pascals. (Photo Source: IBACOS)

7.11

CHAPTER 7. THE OVERALL BUILDING ENVELOPE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 7.11
ENERGY STAR Qualified Homes, Version 3 (Rev. 04) 

Thermal Enclosure System Rater Checklist 

Effective for homes permitted starting 10/1/2011 Revised 8/29/2011 Page 3 of 16 

Home Address: City: State: 

Inspection Guidelines Must

Correct 

Builder

Verified 1 Rater

Verified N/A 

1. High-Performance Fenestration

1.1 Prescriptive Path:Fenestration shall meet or exceed ENERGY STAR requirements 2    

1.2 Performance Path:Fenestration shall meet or exceed 2009 IECC requirements 2    

2. Quality-Installed Insulation

2.1 Ceiling, wall, floor, and slab insulation levels shall meet or exceed 2009 IECC levels 3,4,5    

2.2 All ceiling, wall, floor, and slab insulation shall achieve RESNET-defined Grade I 

installation or, alternatively, Grade II for surfaces with insulated sheathing (see Checklist 

Item 4.4.1 for required insulation levels) 

   

3. Fully-Aligned Air Barriers 6

 At each insulated location noted below, a complete air barrier shall be provided that is fully aligned with the insulation as follows: 

  At interior or exterior surface of ceilings in Climate Zones 1-3; at interior surface of ceilings in Climate Zones 4-8. Also, include 

barrier at interior edge of attic eave in all climate zones using a wind baffle that extends to the full height of the insulation. Include a 

baffle in every bay or a tabbed baffle in each bay with a soffit vent that will also prevent wind washing of insulation in adjacent bays 

  At exterior surface of walls in all climate zones; and also at interior surface of walls for Climate Zones 4-8 7

  At interior surface of floors in all climate zones, including supports to ensure permanent contact and blocking at exposed edge 8,9

3.1 Walls 10

3.1.1 Walls behind showers and tubs    

3.1.2 Walls behind fireplaces    

3.1.3 Attic knee walls    

3.1.4 Skylight shaft walls    

3.1.5 Wall adjoining porch roof    

3.1.6 Staircase walls    

3.1.7 Double walls    

3.1.8 Garage rim / band joist adjoining conditioned space    

3.1.9 All other exterior walls    

3.2 Floors 

3.2.1 Floor above garage    

3.2.2 Cantilevered floor    

3.2.3 Floor above unconditioned basement or unconditioned crawlspace    

3.3 Ceilings 10

3.3.1 Dropped ceiling / soffit below unconditioned attic    

3.3.2 All other ceilings    

4. Reduced Thermal Bridging

4.1 For insulated ceilings with attic space above (i.e., non-cathedralized ceilings), 

uncompressed insulation extends to the inside face of the exterior wall below at the 

following levels: CZ 1 to 5: > R-21; CZ 6 to 8: > R-30 11    

4.2 For slabs on grade in CZ 4 and higher, 100% of slab edge insulated to > R-5 at the depth 

specified by the 2009 IECC and aligned with thermal boundary of the walls 4,5    

4.3 Insulation beneath attic platforms (e.g., HVAC platforms, walkways) > R-21 in CZ 1 to 5; 

 > R-30 in CZ 6 to 8    

4.4 Reduced thermal bridging at above-grade walls separating conditioned from unconditioned space (rim / band joists exempted)

using one of the following options: 12,13

4.4.1 Continuous rigid insulation, insulated siding, or combination of the two; 

 > R-3 in Climate Zones 1 to 4, > R-5 in Climate Zones 5 to 8 14,15, OR; 

   

4.4.2 Structural Insulated Panels (SIPs), OR;    

4.4.3 Insulated Concrete Forms (ICFs), OR;    

4.4.4 Double-wall framing 16, OR;    

4.4.5 Advanced framing, including all of the items below:

4.4.5a All corners insulated > R-6 to edge 17, AND;    

4.4.5b All headers above windows & doors insulated 18, AND;    

4.4.5c Framing limited at all windows & doors 19, AND;    

4.4.5d All interior / exterior wall intersections insulated to the same R-value as the rest 

of the exterior wall 20, AND;

   

4.4.5e Minimum stud spacing of 16” o.c. for 2x4 framing in all Climate Zones and, in 

Climate Zones 5 through 8, 24” o.c. for 2x6 framing unless construction 

documents specify other spacing is structurally required 21    

CHAPTER 7 / BUILDING AMERICA BEST PRACTICES SERIES

7.12 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
ENERGY STAR Qualified Homes, Version 3 (Rev. 04) 

Thermal Enclosure System Rater Checklist 

Effective for homes permitted starting 10/1/2011 Revised 8/29/2011 Page 4 of 16 

Inspection Guidelines Must

Correct 

Builder

Verified 1 Rater

Verified N/A 

5. Air Sealing

5.1 Penetrations to unconditioned space fully sealed with solid blocking or flashing as needed and gaps sealed with caulk or foam 

5.1.1 Duct / flue shaft    

5.1.2 Plumbing / piping    

5.1.3 Electrical wiring    

5.1.4 Bathroom and kitchen exhaust fans    

5.1.5 Recessed lighting fixtures adjacent to unconditioned space ICAT labeled and fully 

gasketed. Also, if in insulated ceiling without attic above, exterior surface of fixture 

insulated to > R-10 in CZ 4 and higher to minimize condensation potential. 

   

5.1.6 Light tubes adjacent to unconditioned space include lens separating 

unconditioned and conditioned space and are fully gasketed 22    

5.2 Cracks in the building envelope fully sealed 

5.2.1 All sill plates adjacent to conditioned space sealed to foundation or sub-floor with 

caulk. Foam gasket also placed beneath sill plate if resting atop concrete or 

masonry and adjacent to conditioned space. 

   

5.2.2 At top of walls adjoining unconditioned spaces, continuous top plates or sealed 

blocking using caulk, foam, or equivalent material    

5.2.3 Sheetrock sealed to top plate at all attic / wall interfaces using caulk, foam, or 

equivalent material. Either apply sealant directly between sheetrock and top plate 

or to the seam between the two from the attic above. Construction adhesive shall 

not be used. 

   

5.2.4 Rough opening around windows & exterior doors sealed with caulk or foam 23    

5.2.5 Marriage joints between modular home modules at all exterior boundary 

conditions fully sealed with gasket and foam    

5.2.6 All seams between Structural Insulated Panels (SIPs) foamed and / or taped per 

manufacturer’s instructions    

5.2.7 In multifamily buildings, the gap between the drywall shaft wall (i.e. common wall) 

and the structural framing between units fully sealed at all exterior boundaries    

5.3 Other openings 

5.3.1 Doors adjacent to unconditioned space (e.g., attics, garages, basements) or 

ambient conditions gasketed or made substantially air-tight    

5.3.2 Attic access panels and drop-down stairs equipped with a durable > R-10 

insulated cover that is gasketed (i.e., not caulked) to produce continuous air seal 

when occupant is not accessing the attic 24    

5.3.3 Whole-house fans equipped with a durable > R-10 insulated cover that is 

gasketed and either installed on the house side or mechanically operated 24    

Rater Name: ____________________________________ Rater Pre-Drywall Inspection Date: _________ Rater Initials: ________ 

Rater Name: ____________________________________ Rater Final Inspection Date: ______________ Rater Initials: ________ 

Builder Employee: Builder Inspection Date: Builder Initials: 

Notes: 

1. At the discretion of the Rater, the builder may verify up to eight items specified in this Checklist. When exercised, the builder’s 

responsibility will be formally acknowledged by the builder signing off on the checklist for the item(s) that they verified. 

2. For Prescriptive Path: All windows, doors, and skylights shall meet or exceed ENERGY STAR Program Requirements for 

Residential Windows, Doors, and Skylights – Version 5.0 as outlined at www.energystar.gov/windows. For Performance Path: All 

windows, doors and skylights shall meet or exceed the component U-factor and SHGC requirements specified in the 2009 IECC – 

Table 402.1.1. If no NFRC rating is noted on the window or in product literature (e.g., for site-built fenestration), select the U-factor 

and SHGC value from tables 4 and 14, respectively, in 2005 ASHRAE Fundamentals, Chapter 31. Select the highest U-factor and 

SHGC value among the values listed for the known window characteristics (e.g., frame type, number of panes, glass color, and 

presence of low-e coating). Note that the U-factor requirement applies to all fenestration while the SHGC only applies to the glazed 

portion. The following exceptions apply: 

a. An area-weighted average of fenestration products shall be permitted to satisfy the U-factor requirements; 

b. An area-weighted average of fenestration products > 50% glazed shall be permitted to satisfy the SHGC requirements; 

c. 15 square feet of glazed fenestration per dwelling unit shall be exempt from the U-factor and SHGC requirements, and 

shall be excluded from area-weighted averages calculated using a) and b), above; 

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CHAPTER 7. THE OVERALL BUILDING ENVELOPE

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 7.13
ENERGY STAR Qualified Homes, Version 3 (Rev. 04) 

Thermal Enclosure System Rater Checklist 

Effective for homes permitted starting 10/1/2011 Revised 8/29/2011 Page 5 of 16 

d. One side-hinged opaque door assembly up to 24 square feet in area shall be exempt from the U-factor requirements and 

shall be excluded from area-weighted averages calculated using a) and b), above; 

e. Fenestration utilized as part of a passive solar design shall be exempt from the U-factor and SHGC requirements, and 

shall be excluded from area-weighted averages calculated using a) and b), above. Exempt windows shall be facing within 

45 degrees of true south and directly coupled to thermal storage mass that has a heat capacity > 20 btu / ft3

x

o

F and 

provided in a ratio of at least 3 sq. ft. per sq. ft. of south facing fenestration. Generally, thermal mass materials will be at 

least 2 in. thick. 

3. Insulation levels in a home shall meet or exceed the component insulation requirements in the 2009 IECC - Table 402.1.1. The

following exceptions apply: 

a. Steel-frame ceilings, walls, and floors shall meet the insulation requirements of the 2009 IECC – Table 402.2.5. In CZ 1 

and 2, the continuous insulation requirements in this table shall be permitted to be reduced to R-3 for steel-frame wall 

assemblies with studs spaced at 24 in. on center. This exception shall not apply if the alternative calculations in d) are 

used; 

b. For ceilings with attic spaces, R-30 shall satisfy the requirement for R-38 and R-38 shall satisfy the requirement for R-49 

wherever the full height of uncompressed insulation at the lower R-value extends over the wall top plate at the eaves. This 

exemption shall not apply if the alternative calculations in d) are used; 

c. For ceilings without attic spaces, R-30 shall satisfy the requirement for any required value above R-30 if the design of the

roof / ceiling assembly does not provide sufficient space for the required insulation value. This exemption shall be limited 

to 500 square ft. or 20% of the total insulated ceiling area, whichever is less. This exemption shall not apply if the 

alternative calculations in d) are used; 

d. An alternative equivalent U-factor or total UA calculation may also be used to demonstrate compliance, as follows: 

 An assembly with a U-factor equal or less than specified in 2009 IECC Table 402.1.3 complies. 

 A total building thermal envelope UA that is less than or equal to the total UA resulting from the U-factors in Table 402.1.3 

also complies. The insulation levels of all non-fenestration components (i.e., ceilings, walls, floors, and slabs) can be 

traded off using the UA approach under both the Prescriptive and the Performance Path. Note that fenestration products 

(i.e., windows, skylights, doors) shall not be included in this calculation. Also, note that while ceiling and slab insulation 

can be included in trade-off calculations, the R-value must meet or exceed the minimum values listed in Items 4.1 through 

4.3 of the Checklist to provide an effective thermal break, regardless of the UA tradeoffs calculated. The UA calculation 

shall be done using a method consistent with the ASHRAE Handbook of Fundamentals and shall include the thermal 

bridging effects of framing materials. The calculation for a steel-frame envelope assembly shall use the ASHRAE zone 

method or a method providing equivalent results, and not a series-parallel path calculation method. 

4. Consistent with the 2009 IECC, slab edge insulation is only required for slab-on-grade floors with a floor surface less than 12 

inches below grade. Slab insulation shall extend to the top of the slab to provide a complete thermal break. If the top edge of the 

insulation is installed between the exterior wall and the edge of the interior slab, it shall be permitted to be cut at a 45-degree angle 

away from the exterior wall. 

5. Where an insulated wall separates a garage, patio, porch, or other unconditioned space from the conditioned space of the house, 

slab insulation shall also be installed at this interface to provide a thermal break between the conditioned and unconditioned slab. 

Where specific details cannot meet this requirement, partners shall provide the detail to EPA to request an exemption prior to the 

home’s qualification. EPA will compile exempted details and work with industry to develop feasible details for use in future revisions 

to the program. A list of currently exempted details is available at: www.enegystar.gov/slabedge. 

6. For purposes of this Checklist, an air barrier is defined as any durable solid material that blocks air flow between conditioned space 

and unconditioned space, including necessary sealing to block excessive air flow at edges and seams and adequate support to 

resist positive and negative pressures without displacement or damage. EPA recommends, but does not require, rigid air barriers. 

 Open-cell or closed-cell foam shall have a finished thickness > 5.5 in. or 1.5 in., respectively, to qualify as an air barrier unless the 

manufacturer indicates otherwise. 

 If flexible air barriers such as house wrap are used, they shall be fully sealed at all seams and edges and supported using 

fasteners with caps or heads > 1 in. diameter unless otherwise indicated by the manufacturer. Flexible air barriers shall not be 

made of kraft paper, paper-based products, or other materials that are easily torn. If polyethylene is used, its thickness shall be > 6 

mil. 

7. EPA highly recommends, but does not require, inclusion of an interior air barrier at band joists in Climate Zone 4 through 8.

8. Examples of supports necessary for permanent contact include staves for batt insulation or netting for blown-in insulation. Batts 

that completely fill a cavity enclosed on all six sides may be used to meet this requirement without the need for supports, even 

though some compression will occur due to the excess insulation, as long as the compressed value meets or exceeds the required 

insulation level. Specifically, the following batts may be used in six-sided floor cavities: R-19 batts in 2x6 cavities, R-30 batts in 2x8 

cavities, R-38 batts in 2x10 cavities, and R-49 batts in 2x12 cavities. For example, in a home that requires R-19 floor insulation, an 

R-30 batt may be used in a six-sided 2x8 floor cavity. 

9. Fully-aligned air barriers may be installed at the exterior surface of the floor cavity in all Climate Zones if the insulation is installed 

in contact with this exterior air barrier and the perimeter rim and band joists of the floor cavity are also sealed and insulated to 

comply with the fully-aligned air barrier requirements for walls. 

CHAPTER 7 / BUILDING AMERICA BEST PRACTICES SERIES

7.14 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
ENERGY STAR Qualified Homes, Version 3 (Rev. 04) 

Thermal Enclosure System Rater Checklist 

Effective for homes permitted starting 10/1/2011 Revised 8/29/2011 Page 6 of 16 

10. All insulated vertical surfaces are considered walls (e.g., exterior walls, knee walls) and must meet the air barrier requirements for 

walls. All insulated ceiling surfaces, regardless of slope (e.g., cathedral ceilings, tray ceilings, conditioned attic roof decks, flat 

ceilings, sloped ceilings), must meet the requirements for ceilings. 

11. The minimum designated R-values must be achieved regardless of the trade-offs determined using an equivalent U-factor or UA

alternative calculation. Note that if the minimum designated values are used, they must be compensated with higher values 

elsewhere using an equivalent U-factor or UA alternative calculation in order to meet the overall insulation requirements of the 

2009 IECC. Also, note that these requirements can be met by using any available strategy, such as a raised-heel truss, alternate 

framing that provides adequate space, and / or high-density insulation. In Climate Zones 1 through 3, one option that will work for 

most homes is to use 2x6 framing, an R-21 high-density batt, and a wind baffle that only requires 0.5 in. of clearance. 

12. Up to 10% of the total exterior wall surface area is exempted from the reduced thermal bridging requirements to accommodate

intentional designed details (e.g., architectural details such as thermal fins, wing walls, or masonry fireplaces; structural details, 

such as steel columns). It shall be apparent to the Rater that the exempted areas are intentional designed details or the exempted 

area shall be documented in a plan provided by the builder, architect, designer, or engineer. The Rater need not evaluate the 

necessity of the designed detail to qualify the home. 

13. Mass walls utilized as the thermal mass component of a passive solar design (e.g., a Trombe wall) are exempt from this item. To 

be eligible for this exemption, the passive solar design shall be comprised of the following five components: an aperture or 

collector, an absorber, thermal mass, a distribution system, and a control system. For more information, see: 

http://www.energysavers.gov/your_home/designing_remodeling/index.cfm/mytopic=10270. 

 Mass walls that are not part of a passive solar design (e.g., CMU block or log home enclosure) shall either utilize the strategies 

outlined in Section 4.4 or the pathway in the assembly with the least thermal resistance shall provide > 50% of the applicable 

component insulation requirement in the 2009 IECC – Table 402.1.1. 

14. If used, insulated siding shall be attached directly over a water-resistive barrier and sheathing. In addition, it shall provide the 

required R-value as demonstrated through either testing in accordance with ASTM C 1363 or by attaining the required R-value at 

its minimum thickness. Insulated sheathing rated for water protection can be used as a water resistant barrier if all seams are

taped and sealed. If non-insulated structural sheathing is used at corners, advanced framing details listed under Item 4.4.5 shall be 

met for those wall sections. 

15. Steel framing shall meet the reduced thermal bridging requirements by complying with Item 4.4.1 of the Checklist. 

16. Double-wall framing is defined as any framing method that ensures a continuous layer of insulation covering the studs to at least 

the R-value required in Section 4.4.1 of the Checklist, such as offset double-stud walls, aligned double-stud walls with continuous 

insulation between the adjacent stud faces, or single-stud walls with 2x2 or 2x3 cross-framing. In all cases, insulation shall fill the 

entire wall cavity from the interior to exterior sheathing except at windows, doors and other penetrations. 

17. All exterior corners shall be constructed to allow access for the installation of > R-6 insulation that extends to the exterior wall 

sheathing. Examples of compliance options include standard-density insulation with alternative framing techniques, such as using 

three studs per corner, or high-density insulation (e.g., spray foam) with standard framing techniques. 

18. Header insulation shall be ≥ R-3 for wall assemblies with 2x4 framing, or equivalent cavity width, and ≥ R-5 for all other assemblies 

(e.g., with 2x6 framing). Compliance options include continuous rigid insulation sheathing, SIP headers, other prefabricated 

insulated headers, single-member or two-member headers with insulation either in between or on one side, or an equivalent 

assembly, except where a framing plan provided by the builder, architect, designer, or engineer indicates that full-depth solid

headers are the only acceptable option. The Rater need not evaluate the structural necessity of the details in the framing plan to 

qualify the home. Also, the framing plan need only encompass the details in question and not necessarily the entire home. R-value 

requirement refers to manufacturer’s nominal insulation value. 

19. Framing at windows shall be limited to a maximum of one pair of king studs and one pair jack studs per window opening to support 

the header and window sill. Additional jack studs shall be used only as needed for structural support and cripple studs only as

needed to maintain on-center spacing of studs. 

20. Insulation shall run behind interior / exterior wall intersections using ladder blocking, full length 2x6 or 1x6 furring behind the first 

partition stud, drywall clips, or other equivalent alternative. 

21. Vertical framing members shall either be on-center or have an alternative structural purpose (e.g., framing members at the edge of 

pre-fabricated panels) that is apparent to the Rater or documented in a framing plan provided by the builder, architect, designer, or 

engineer. The Rater need not evaluate the structural necessity of the details in the framing plan to qualify the home. Also, the 

framing plan need only encompass the details in question and not necessarily the entire home. No more than 5% of studs may lack

an apparent or documented structural purpose, which is equivalent to one vertical stud for every 30 linear feet of wall, assuming 16 

in. o.c. stud spacing. 

22. Light tubes that do not include a gasketed lens are required to be sealed and insulated > R-6 for the length of the tube. 

23. In Climate Zones 1 through 3, stucco over rigid insulation tightly sealed to windows and doors shall be considered equivalent to 

sealing rough openings with caulk or foam. 

24. Examples of durable covers include, but are not limited to, pre-fabricated covers with integral insulation, rigid foam adhered to 

cover with adhesive, or batt insulation mechanically fastened to the cover (e.g., using bolts, metal wire, or metal strapping).

7.15

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Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 7.15
CHAPTER 7 / BUILDING AMERICA BEST PRACTICES SERIES

7.16 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
In its simplest form, building envelopes are cubes that incorporate 

three parts: the floor, four walls, and a roof. In actuality, these 

assemblies are complicated combinations of rectangles, triangles, 

and even domes. Building homes that deliver comfort, durability, 

and energy performance requires paying attention to the details of 

each assembly. This chapter provides guidance on controlling liquid 

and water vapor, air flow, and heat flow in the foundation, wall, 

and roof assemblies.

Foundation Assemblies 

Slabs, crawlspaces, and basements are all common foundation types 

in the mixed-humid climate. Slabs can be monolithic or poured inside 

stem walls on footers. The foundation forms the solid underpinning 

for a house’s structural integrity. It also provides the boundary 

between the house and the ground, preventing the unwanted transfer 

of moisture, air, heat, and soil gases from the ground to occupied 

living spaces. It plays an important role in building durability and 

occupant health as well as in building energy efficiency. See Chapter 

14 for examples of detailed foundation drawings that show measures 

for controlling moisture, air, and heat flow. 

Controlling Liquid Water in Foundations

Proper site grading directs surface water away from building 

foundations and walls. The steeper the slope away from the building, 

the better the water will drain. All building foundations should be 

designed and constructed to prevent the entry of moisture. 

In vented crawlspaces, the dominant source of moisture is bulk 

water, not water vapor from indoor or outdoor air condensing in 

the crawlspace. Water enters the crawlspace because of improper 

Chapter 8.

Building Envelope 

Sub-Assemblies

CHAPTER TOPICS

8.1 Foundation Assemblies

8.12 Wall Assemblies

8.21 Roof Assemblies

8.25 Window and Door Assemblies

Drain all water away 

from the structure

(Figure adapted from 

Building Science Corporation)

Drain Site

Drain Roof

Drain Building

Drain Site

Drain Wall Drain Materials

Drain Components

Drain Openings

Most home designs today are far more 

complicated than four walls and a roof. 

Builders need to pay attention to the 

details of each assembly to deliver 

energy performance (Photo Source: 

Urbane Homes).

8.1

CHAPTER 8. BUILDING ENVELOPE SUB-ASSEMBLIES

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 8.1
irrigation practices, ground slope, rain runoff, high groundwater 

tables, rain during the construction process, and leaks in plumbing 

(Baker and Murray 2006). These sources can be controlled by careful 

site grading, installation of drainage systems, proper foundation 

design and water-proofing measures, appropriate landscaping, and 

other measures described below. 

Most foundation water leakage or intrusion is due to either bulk 

moisture leaks or capillary action. Bulk moisture is the flow of liquid 

water. Capillary action occurs when water wicks or is absorbed into 

small cracks and pores in building materials, such as masonry block, 

concrete, or wood. Moisture can also be carried by soil gas into the 

home. Moisture may cause structural decay and can contribute to 

human health problems. 

The following practices apply to foundation systems.

•	 Design the house structure with overhangs, gutters, drainage 

planes, and flashing to shed rainwater and conduct it away from 

the house [as required in 2009 and 2012 IRC R703.1 and R703.8].

•	 Slope top soil to drain away from the house. [2009 and 2012 IRC 

R401.3 require that the lot be graded to fall at least 6 inches in the 

first 10 feet from the foundation.] Building America recommends 

a surface grade of at least 5% for at least 10 feet around and away 

from the entire structure.

•	 Drain driveways, garage slabs, patios, stoops, and walkways 

away from the structure. [2009 and 2012 IRC R401.3 require that 

impervious surfaces within 10 feet of the building foundation be 

sloped at least 2% away from the building.]

•	 Keep all untreated wood away from contact with earth and concrete. 

Keep wood and fiber cement siding at least 8 inches from the soil surface 

to minimize damage from rain splashing up from the ground surface.

•	 Install a protective shield such as a plastic L bracket, gasket, 

or water-proof membrane between the foundation wall stem 

and sill plate to keep water from wicking into the wall from the 

foundation. Metal flashing can also serve this function and serve 

as a termite shield [2009 and 2012 IRC R318.3].

•	 Damp-proof or water-proof all below-grade portions of the 

exterior concrete foundation walls [2009 and 2012 IRC R406]. 

•	 Cover exposed earth in crawlspace floors with 6-mil polyethylene 

sheeting. All joints of the vapor retarder shall overlap by 6 inches 

and be sealed or taped. The edges of the vapor retarder shall extend 

at least 6 inches up the stem wall and shall be attached to the stem 

(top) Make sure the downspouts are 

continuous to the ground and extend to at 

least 3 feet from the house. Install flashing 

at the roof valleys and edges and install rain 

gutters to guide water off the roof and away 

from the house. (Photo Source: EPA, photo 

by Terry Brennan)

(bottom) Insight Homes in Seaford, 

Delaware, uses a sealed conditioned 

crawlspace. The exterior below-grade 

surface is waterproofed. The crawlspace 

walls are insulated on the interior side 

with R-10 extruded polystyrene rigid foam. 

The floor is covered with two layers of 

polythylene sheeting that is sealed to the 

perimeter walls.

CHAPTER 8 / BUILDING AMERICA BEST PRACTICES SERIES

8.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
wall. [The 2009 IECC 402.2.9 and 2012 IECC 402.2.10 and the 2009 

and 2012 IRC 408.3 require a vapor retarder over exposed earth in 

unvented crawlspaces.]

•	 Damp proof the exposed portion of the foundation with latex 

paint or other sealants. 

•	 Apply a protective coating over rigid foam exterior foundation

wall insulation at above-grade applications. Examples of protective

coverings include flashing, fiber-cement board, parging, treated

plywood, or EPDM membrane.

•	 Place a continuous drainage plane or free-draining materials over

the damp proofing or exterior insulation on foundation walls to

channel water to the foundation drain and relieve hydrostatic

pressure. Drainage plane materials include impervious plastic

mats, high-density fiberglass foam insulation boards, and

uniformly graded gravel.

•	 Place slabs and crawlspace floors above the surrounding grade. 

•	 Treat footings poured independent of slabs or foundation walls 

with a bituminous damp-proof coating, masonry capillary-break 

paint, or a layer of 6-mil polyethylene plastic to isolate the footing 

from the remainder of the assembly.

•	 Place 6-mil polyethylene sheeting or rigid foam insulation directly 

beneath the slab or basement floor. Wrap sheeting continuously 

under the slab and footings up to grade.

•	 Do not place a sand layer between the vapor retarder and the 

concrete slab or basement floor. Differential drying and cracking 

is better handled with a low water-to-concrete ratio and wetted 

burlap covering during initial curing.

•	 Place a 4-inch-deep, 3⁄4-inch gravel bed directly beneath the 

polyethylene sheeting to act as a capillary break and drainage pad.

•	 Ensure that the lowest excavated site foundation level is above the 

local groundwater table at its maximum elevation [per 2009 and 

2012 IRC R408.6].

•	 Install a perimeter drain below the drainage plane along the side

(not on top of) footings for all basements and crawlspaces where

the floor is below grade.

•	 Place drainage systems below basement floors.

•	 In flood-prone areas, build homes on piers with floors one foot 

above the base flood elevation.

David Weekley Homes, Houston, Texas 

Division, uses a slab foundation including a 

4-in.-thick post-tensioned monolithic slab 

with turned-down edges poured over 6-mil 

polyethylene, which serves as a capillary 

break. Slab edge insulation is not used 

due to termite risk. 

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CHAPTER 8. BUILDING ENVELOPE SUB-ASSEMBLIES

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 8.3
Frost Heave and Adfreeze

Frost heave occurs when ice crystals form from water at the freezing 

plane of soil that is saturated. As the water is pulled up into ice 

crystals, the ground below dries drawing in more water from the 

surrounding soil, which is in turn drawn up into ice crystals, thus 

creating an upward thrust of soil and ice. The concern is that this 

expanding soil and ice, or frost heave, will push against building 

foundations causing them to crack and buckle. However, frost 

expansion always follows the direction of heat loss. So expansion 

will be up and away from the building foundation if the basement 

is heated. According to Joseph Lstiburek at Building Science 

Corporation, several years of investigative work by the Canadian 

Department of Energy, Mines, and Resources found no evidence 

of frost-damaged foundations in homes with heated basements, 

regardless of whether the walls were insulated or uninsulated, and 

regardless of whether the insulation was on the interior or exterior 

of the wall (Lstiburek 2011). In insulated basements heat loss is 

greatly reduced but the direction of heat loss remains outward, 

and frost direction will follow the direction of heat loss. Another 

concern is adfreeze, or adhesion freezing, where saturated soil freezes 

against a foundation wall, adhering to it and lifting the wall when 

it heaves upward. Fortunately water molecules also migrate in the 

direction of heat loss so, in cold soil, water will migrate away from 

the foundation wall of a heated basement, reducing the strength of 

adhesion bonds and the likelihood of damage. Lstiburek notes that 

this is again true in insulated as well as uninsulated basements as 

long as they are heated (Lstiburek 2011).

If you don’t want to heat the basement, you can lay a skirt of R-10 

rigid insulation around the perimeter of the building laid several 

inches below ground that extends horizontally a distance equal to the 

average frost depth. A better option is to avoid frost-susceptible soils 

and water saturation at the foundation. Use granular soil, not fine 

or silty soil for backfill along the foundation and provide good site 

grading and perimeter drainage as described above (Lstiburek 2011).

•	 Place footings below frost depth.

•	 Use gravel with no more than 3% grains finer than 0.02 mm. Don’t 

use clays, silts, tills, or very fine-grained sand as a backfill because 

they are susceptible to frost action.

•	 Prevent saturation of soil at foundation by grading the site away 

from the house and providing perimeter drainage at the footing.

Unvented, insulated crawlspaces are 

recommended in the eastern and 

midwestern United States, where high 

humidity levels can cause moisture 

problems in vented crawlspaces.

CHAPTER 8 / BUILDING AMERICA BEST PRACTICES SERIES

8.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Controlling Water Vapor in Foundations

Water vapor from basement and slab foundations can be controlled 

using a vapor barrier under the slab as described above. Properly 

constructed slab foundations will avoid the moisture issues that are 

sometimes problematic in crawlspace foundations. 

If a crawlspace foundation is to be used, the traditional method for 

building them is a vented crawlspace with vents cut in the foundation 

walls and insulation installed under the floor above the crawlspace. 

Building science research indicates that unvented, insulated crawlspaces 

may be preferable in certain climates. Unvented crawlspaces are 

allowed in the 2009 and 2012 IRC R408.3 as long as the exposed earth 

is covered with a Class 1 vapor retarder that is overlapped at edges, 

taped, and sealed to walls; the walls are insulated; and the crawlspace is 

mechanically vented with an exhaust fan or supplied with conditioned 

air and a return duct (check for any state restrictions).

In areas where summers are humid, some building scientists note that 

moisture can be carried into the crawlspace in the air drawn through 

open foundation wall vents. When this warm, moist air reaches cooler 

structural framing, the moisture can condense onto the framing and 

cause mold and moisture damage. In winter, cold air is drawn into 

the crawlspace and does little to dry out crawlspaces, but can lower 

temperatures, cause condensation on warm floor joists, and freeze 

exposed water pipes. In these climate conditions, which are common in 

the mixed-humid climate, researchers recommend sealing, insulating, 

and conditioning the crawlspace. (See sidebar.)

Some moisture in crawlspaces occurs from soil vapor. To control water 

vapor from soil in crawlspaces, do the following:

•	 Install 6-mil polyethylene across the entire ground surface. 

•	 Overlap all seams by 12 inches and tape. 

•	 Seal the polyethylene to the walls with pressure-treated wood 

strapping nailed at least 6 inches up the walls or to a height equal 

to ground level [2009 IECC 402.2.9; 2012 IECC 402.2.10]. 

Some Building America teams recommend installing one polyethylene 

groundcover at the beginning of construction; then, when construction 

is completed, installing a second sheet, to cover any rips in the first one, 

and sealing it to the walls. To improve durability, a minimum 2-inch 

concrete slab can be poured over the polyethylene.

Sealed, conditioned crawlspaces offer non-energy advantages over 

vented crawlspaces that are worth considering, such as minimizing 

bulk water intrusion, and pest intrusion. While unvented crawlspaces 

To Vent or Not to Vent? 

Crawlspace Research Looks 

at Both Sides 

Two DOE-funded studies compared vented 

versus unvented crawlspaces in warm and 

humid versus dry and cold environments. 

A study conducted by Advanced Energy 

of sealed versus unsealed crawlspaces 

in hot, humid Baton Rouge and cold, dry 

Flagstaff found that the sealed, insulated 

crawlspaces were drier than the unsealed 

crawlspaces. In Baton Rouge average 

relative humidity was over 80% in the 

unsealed crawlspaces and under 60% in the 

sealed crawlspaces; in Flagstaff average 

relative humidity was just under 70% 

in unsealed versus under 50% in sealed 

crawlspaces (Advanced Energy 2009). 

A DOE-funded study by Washington State 

Energy Office found that in the west, 

where summers are dry and winters are 

heating-dominated or in dry climates 

where relative humidity in vented 

crawlspaces stays low year-round, there 

is less likelihood of condensation-related 

moisture problems in the crawlspace so 

crawlspaces could be vented or unvented, 

as long as radon is dealt with. The WSU 

study compared crawlspaces in cold, 

dry Moses Lake, Washington, and damp 

Vancouver, Washington. WSU found that 

even in the marine climate in Vancouver, all 

of the crawlspaces stayed well below the 

dew point, although homes with vented 

crawlspaces had slightly higher relative 

humidity than those with unvented crawls 

(Nordeen 2008). 

In the cold climate homes, both 

studies found an energy penalty when 

installing ducts in the sealed conditioned 

crawlspaces, due to winter heat loss 

through the uninsulated floor. Both studies 

also found elevated radon levels in the 

sealed, insulated crawlspaces. Among 

the conclusions drawn from the studies: 

sealed crawlspaces make sense in humid 

environments; vented crawlspaces can 

work in cold and dry climates; best practice 

is to keep ducts out of crawlspaces; slabs 

may be preferable; and a passive radon 

venting system should always be installed 

as a precautionary measure.

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CHAPTER 8. BUILDING ENVELOPE SUB-ASSEMBLIES

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 8.5
can provide a better environment for HVAC equipment than a 

vented crawlspace, the best practice is to locate the furnaces and 

ducts in conditioned space. 

Controlling Air Infiltration in Foundations

The greatest challenges for air sealing are at the intersections 

of different building assemblies. [The 2009 IECC 402.4 requires 

air sealing of the building thermal envelope at rim joists, utility 

penetrations, and other areas. In the 2012 IECC, areas to be air sealed 

are described in Table R402.4.1.1.] Building America recommends the 

following foundation air sealing techniques:

•	 Install a sill gasket between the concrete foundation wall and the 

bottom plate to control air infiltration and to serve as a capillary break.

•	 Seal all panel joints to stop air leakage through subfloor sheathing 

installed over unconditioned spaces such as vented crawlspaces, 

unconditioned garages, or cantilevered floors over exterior walls.

•	 Use spray foam to air seal and insulate at the rim joist.

Controlling Heat Flow in Foundations

Insulation requirements for the 2009 and 2012 IECC are found in 

Table R402.1.1. The 2009 and 2012 IECC require zero insulation for 

slabs in IECC Climate Zone 3. In IECC Climate Zone 4 (except 

Marine) R-10 insulation is required extending down and/or under 

or out 2 feet. If the slab floor contains radiant heating elements, 

then R-5 insulation must be added to the required amount. Both the 

2009 and 2012 IECC require a basement wall insulation amount of 

R-5 continuous insulation on the interior or exterior of the home in 

IECC Climate Zone 3 above the warm-humid line, or R-10 in IECC 

Climate Zone 4 (except marine). Alternatively, builders can install 

R-13 cavity insulation on the inside of the basement walls. Insulated 

crawlspace R-value requirements are identical to the basement 

requirements. Slab-edge insulation is not required in jurisdictions 

designated by the code official as having a very heavy termite 

infestation probability. See the 2009 IRC and the 2012 IRC R318.4 

for restrictions on the use of rigid foam for below-grade insulation 

in areas where the probability of termite infestation is very heavy 

(which includes parts of some southern states, see map page 8.11). 

For More Information on Foundations

Advanced Energy. 2005. Closed Crawl Spaces, prepared for DOE by Advanced Energy, 

www.advancedenergy.org/buildings/knowledge_library/

Advanced Energy. 2009. Closed Crawl Spaces: Top Performers Nationwide, prepared for 

the U.S. Department of Energy, www.advancedenergy.org/buildings/knowledge_library/

crawl_spaces/pdfs/Closed%20Crawl%20Spaces.pdf

Code/Above Code 

Foundation Insulation

Code Requirements found in 2009 IECC 

and 2012 IECC Table R402.1.1

Code IECC Climate Zone

IECC Climate 

Zone 3 4++

Underfloor 

Insulation 

2009 IECC

2012 IECC

R-19

R-19

R-19

R-19

Basement 

Wall Insulation 

2009 IECC

2012 IECC

R-5/13+

R-5/13+ 10/13*

10/13*

Slab Edge 

Insulation

2009 IECC

2012 IECC

R-0

R-0

10, 2ft**

10, 2ft**

Above Code

ENERGY STAR 

Version 3.0

Insulation levels shall 

meet or exceed 2009 

IECC levels and achieve 

Grade 1 installation per 

RESNET standards. 

 + For areas in IECC Climate Zone 3 

above the warm-humid line.

++ IECC Climate Zone 4, except marine.

 * R-5 continuous insulated sheathing or 

R-13 cavity insulation.

** Add R-5 slab edge for heated slabs.

CHAPTER 8 / BUILDING AMERICA BEST PRACTICES SERIES

8.6 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Baker, Ken, and Chuck Murray. 2006. Crawlspace Issues in the Northwest. Washington State 

University Extension Energy Program. www.kenergy.us/pdf/Regional%20Crawlspace_final.pdf

Building Science Corporation, Crawlspace Insulation, Information Sheet 512.

www.buildingscience.com/documents/information-sheets/5-thermal-control/crawlspaceinsulation/?searchterm=512

Dastur, C., M. Mauceri, B. Hannas, and D. Novosel. 2009. Closed Crawl Space Performance: 

Proof of Concept in the Production Builder Market Place, by Advanced Energy and the 

National Center for Energy Management and Building Technologies for the U.S. Department 

of Energy, www.advancedenergy.org/buildings/knowledge_library/crawl_spaces/index.

html?#reports

EPA. 2010. “Technical Guidance to the Indoor airPLUS Construction Specification: 

1. Moisture Control - Water-Managed Roof Assemblies,” www.epa.gov/indoorairplus/

technical/moisture/1_7.html

Journal of Light Construction. 1997. “Troubleshooting Guide to Residential Construction.” 

The Journal of Light Construction, Ed. Steven Bliss, Williston, Vermont.

Lstiburek, Joseph. 2004. Builders Guides. Guides to mixed humid, hot-dry, mixed-dry, and 

cold climates, available for purchase at www.eeba.org/bookstore. 

Lstiburek, Joseph. 2006. EEBA Water Management Guide, available for purchase at 

www.eeba.org/bookstore/prod-Water_Management_Guide-9.aspx 

Lstiburek, Joseph. 2008. Concrete Floor Problems, BSI-003, Building Science.com. 

www.buildingscience.com/documents/insights/bsi-003-concrete-floor-problems 

Lstiburek, Joseph. 2011. Double Rubble Toil and Trouble, Insight 045, Feb. 2011, Building 

Science Corporation, www.buildingscience.com/documents/insights/bsi-045-doublerubble-toil-trouble/

Lubliner, Michael, Larry Palmiter, David Hales, and Andrew Gordon. 2007. “Crawlspace 

Design in Marine and Cold Climates,” in Thermal Performance of the Exterior Envelopes of 

Buildings X, Proceedings of ASHRAE THERM X, Clearwater, FL, Dec. 2007. www.ornl.gov/sci/

buildings/2010/Session%20PDFs/96_New.pdf 

Nordeen, Gary. 2008. Unvented Crawl Spaces, Washington State University Extension 

Energy Program, www.energy.wsu.edu/pubs/

Yost, Nathan. May 2003. “The Case for Conditioned, Unvented Crawlspaces.” Building Safety 

Journal. www.crawlspaces.org

Slab Foundation Insulation

Where permitted and required by code, slabs in the mixed-humid 

climate should be insulated at the perimeter with borate-treated 

foam board or rigid fiberglass insulation approved for below-grade 

use. Building America recommends that rigid insulation be placed 

on the interior side of the stem wall from the slab to the top of 

the footing. Rigid foam insulation can also be laid underneath 

the slab. This provides additional moisture control and minimizes 

the likelihood of condensation and mold in carpeting and floor 

coverings over an uninsulated floor.

Some code officials may require a gap between exterior insulation 

and wood foundation elements to provide a termite inspection 

area. Exterior insulation should be applied from the top of the 

foundation wall to the bottom of the frost line. The exterior face of 

the insulation exposed to outside air should be covered with flashing, 

fiber cement board, parging (stucco type material), treated plywood, 

or EPDM membrane material.

For More Information on 

Slab Foundations

Building Science Corporation. 2004. Houses that 

Work. www.nrel.gov/docs/fy04osti/34585.pdf

Building Science Corporation. 2009. Slab Edge 

Insulation, Information Sheet 513, 

www.buildingscience.com/documents/informationsheets/5-thermal-control/slab-edge-insulation/

The American Society of Civil Engineers. 

Standard 32-01: Design and Construction of 

Frost-Protected Shallow Foundations.

University of Minnesota, Building Foundations 

Research Program, Frost Protected Shallow 

Foundations Design Specifications. 

www.buildingfoundation.umn.edu/

MHFAfrostFoundation.htm

8.7

CHAPTER 8. BUILDING ENVELOPE SUB-ASSEMBLIES

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 8.7
Building Science Corporation recommended this wall detail for this home in Montgomery County, Maryland. Additional wall 

schematics for other mixed-humid climate locations are shown in Chapter 14. (Figure Source: Building Science Corporation)

One House Design in the Mixed-Humid Climate – 

Slab Foundation, Blown Cellulose Walls and Ceiling, Exterior XPS Sheathing 

CHAPTER 8 / BUILDING AMERICA BEST PRACTICES SERIES

8.8 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Crawlspace Insulation

Two methods are in use for insulating crawlspaces. The first, in 

common use over the last several decades, is to insulate the underside 

of the building floor and locate screened vents above grade in the 

foundation walls to provide the unconditioned crawlspace with 

ventilation. With ventilated crawlspaces, it is essential to air seal and 

properly insulate the underside of the first floor and tightly seal and 

insulate any ducts located in the crawlspace. 

Another approach, referred to above, is sealed, conditioned 

crawlspaces with foundation side walls insulated on either the 

interior or exterior. Unvented, conditioned crawlspaces can provide 

a conditioned space for furnaces and ducts, although best practice is 

to not locate furnaces and HVAC equipment in the crawlspace. 

If you have a vented crawlspace or basement (not recommended in 

the mixed-humid climate), here are recommendations for insulating 

the floor (Advanced Energy 2005):

•	 Install batt insulation at the sub-floor without gaps or compression 

and in full contact with the sub-floor to achieve the nominal 

R-value. Insulating open-web floor truss systems with batt 

insulation is discouraged due to the difficulty in insulating the 

openings in the truss structure. Better options for insulating openweb floor truss systems include using spray foam or netting the 

bottom of the trusses and completely filling the cavity with blown 

insulation. These strategies would likely also improve insulation 

performance in wooden I-beam floor structures.

If you install an unvented crawlspace or basement, here are 

recommendations for insulating the walls (Advanced Energy 2005):

•	 Place insulation on either the interior surface, the exterior surface, 

or inside of the perimeter wall (for example, use insulated concrete 

form foundation wall).

•	 Use a rigid foam or other non-porous insulation material. Rigid 

fiberglass is not eaten by termites.

•	 Provide a termite inspection gap of at least 3 inches (or as required 

by local code officials) between the top of the insulation and the top 

of the stem wall and between the bottom of the insulation and the 

floor of the crawlspace (Dastur et al. 2009).

•	 Seal the top of the vapor retarder to the wall with duct mastic 

or equivalent sealant. The mastic or a light colored paint can be 

continued up over the inspection gap to improve inspectability by 

pest control professionals.

•	 Insulate the band joist with batt insulation, which can be removed 

and repositioned easily for termite inspections.

For More Information on 

Basement Insulation

DOE. 2010. Building America Stage Gate 3 

Mixed-Humid 40% 2010 Project Management 

Milestone Report. Prepared for IBACOS for the 

U.S. Department of Energy Building America 

Program. www.buildingamerica.gov

Broniek, John. 2003. Builder System 

Performance Packages Technical Report. 

Prepared by IBACOS for the Building America 

Program. Available at www.buildingamerica.gov

in the publications section.

Building Science Corporation. 2006. 

Read this Before You Design, Build or 

Renovate, Building Science Primer 040, 

www.buildingscience.com/documents/primers/ 

plonearticlemultipage.2006-12-05.5229931729/

Building Science Corporation. 2009. Basement 

Insulation, Info-511, May 14, 2009, www.

buildingscience.com/documents/informationsheets/5-thermal-control/basement-insulation

DOE. 2009. Basement Insulation. U.S. 

Department of Energy, Energy Savers, 

www.energysavers.gov/your_home/insulation_

airsealing/index.cfm/mytopic=11470

Lstiburek, Joseph. 2005. Builder’s Guide to 

Mixed-Humid Climates. Building Science Press. 

Energy and Environmental Building Association. 

Westford, MA.

Lstiburek, Joseph. 2011. Double Rubble Toil 

and Trouble, Insight 045, Feb. 2011, Building 

Science Corporation, www.buildingscience.com/

documents/insights/bsi-045-doublerubble-toiltrouble/

Yost, Nathan, and Joseph Lstiburek. 2002. 

Basement Insulation Systems. Prepared by 

Building Science Corporation for the Building 

America Program. www.eere.energy.gov/

buildings/building_america/pdfs/db/35017.pdf

8.9

CHAPTER 8. BUILDING ENVELOPE SUB-ASSEMBLIES

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 8.9
Highest Potential

Moderate Potential

Low Potential

Zone designation for Puerto Rico 

is under development.

EPA Radon Zone Map 

EPA recommends consulting the EPA 

Map of Radon Zones document (EPA402-R-03-071) when using this map. 

Radon levels in individual homes can vary. 

All homes should be tested regardless 

of geographic location. Passive radon 

strategies should be employed (Image 

source: www.epa.gov/radon/zonemap.html).

For More Information 

on Radon Control 

EPA. 2009. Model Standards and Techniques for 

Control of Radon in New Residential Buildings. 

U.S. Environmental Protection Agency, accessed 

June 6, 2009. www.epa.gov/radon/pubs/

newconst.html#Principles.

EPA. 2009. EPA Map of Radon Zones, 

U.S. Environmental Protection Agency,

www.epa.gov/radon/zonemap.html

EPA. 1995. Passive Radon Control System 

for New Construction, EPA 402-95-012. 

U.S. Environmental Protection Agency, 

www.epa.gov/radon/rrnc/moreinfo.html

Basement Insulation

Basements are a common foundation system in the mixed-humid 

climate. Wall insulation in basements is similar to that described for 

crawlspaces. Basement floors are insulated in the same way as slabs. 

Regardless of the insulation type used, a capillary break should 

be installed on the top of the footing between the footing and the 

perimeter foundation wall to control “rising damp” and a second 

capillary break should be installed between the foundation wall 

and framing.

Controlling Other Foundation Issues

Radon Control 

The mixed-humid climate includes counties in the lowest to highest 

potential regions for radon gas emissions (see EPA map). Regardless 

of what county you are building in, the EPA cautions that local 

radon levels may vary and recommends that all homes be tested. As 

it is impossible to predict radon accumulation levels in houses prior 

to construction, Building America recommends that inexpensive 

radon-control measures be incorporated when building new homes.

Measures taken to control foundation moisture are also important 

first steps in controlling radon. A layer of gravel (4-inch minimum) 

under the slab provides a path for radon and other soil gas to escape 

to the atmosphere rather than being drawn into the house. A sealed 

vapor retarder helps to block soil gas entry into the house. 

One measure recommended by the EPA to control radon and other 

soil gases is a passive soil gas stack that vents to the roof and is 

connected to a horizontal perforated drain pipe embedded in the 

gravel under the slab, basement floor, or crawlspace ground cover. 

This system is often installed as a precaution even when no evidence 

of radon has been shown, because it is far easier to install during 

construction than to come back later and retrofit an under-slab 

venting system. The pipe can act as a passive vent. If it turns out the 

house has unacceptable radon levels, a fan can be added to the stack 

to actively draw soil gas away from the house. An electrical outlet 

should be installed in the attic for possible future fan installation. 

To determine potential radon levels in the county in which you are 

building, see the EPA radon map at www.epa.gov/radon/zonemap.html. 

[Many of these radon control recommendations can be found in the

2009 and 2012 IRC, Appendix F.]

CHAPTER 8 / BUILDING AMERICA BEST PRACTICES SERIES

8.10 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Landscaping

Landscaping is a critical element in the marketability of a house. 

Plants also can be used to shade foundations and reduce cooling 

loads. Choosing native plants results in the need for less irrigation 

and, thus, less chance for irrigation water to create a moisture 

problem in the house. 

Building America recommends plants be kept at least 18 inches from 

the finished structure, with any supporting irrigation directed away 

from the finished structure. Decorative ground cover, such as mulch 

or pea stone, should be no more than 2 inches deep for the first 18 

inches from the finished structure to assist drainage. 

Pest Control

The Termite Infestation Probability Map, Figure R301.2(6) in the 

2009 IRC and 2012 IRC, shows the probability of termite infestation 

across the mixed-humid climate. The 2009 IRC and 2012 IRC R318.1

dictates one or more of the following termite treatments: chemical 

termiticides; termite baiting; pressure/preservative treated wood; 

naturally termite-resistant wood; physical barriers, and steel framing.

In addition Building America recommends:

•	 Keep all wood (including siding, decking, and fencing that attaches 

to the house) from soil contact to minimize the presence of wet wood.

•	 Use termite flashing.

•	 Keep plants at least 18 inches from house.

•	 Maintain at least 8 inches between the ground and wood siding.

(top) Place plants at least 18 inches 

from finished structure and direct 

irrigation away from the foundation.

(middle) Preventive measures by builders 

can reduce the likelihood that termites 

will cause large-scale destruction later 

on. (Photo source: Jody Green)

(bottom) Green Coast Enterprises uses 

termite-resistant borate pressure-treated 

lumber throughout its homes in 

New Orleans.

Termite Probability Map

Moderate to Heavy

Very Heavy

Slight to Moderate

None to Slight

Termite Infestation 

Probability

(Figure Source: 2009 

and 2012 IRC R301.2(6))

Nearly all of the mixed-humid 

climate is subject to a moderate 

to heavy probability of termite 

infestation.

8.11

CHAPTER 8. BUILDING ENVELOPE SUB-ASSEMBLIES

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 8.11
Wall Assemblies

Controlling the intrusion of water and the movement of water 

vapor, air, and heat through the building envelope by proper 

design and construction of wall assemblies are major goals in 

the mixed-humid climate zone.

Controlling Liquid Water in Walls

Nearly all walls leak. Builders should assume some rainwater will 

get through the outer surface of the wall (i.e., the rain screen layer) 

and plan for it by including a drainage gap and a drainage plane to 

stop this water and direct it down and out of the building assembly. 

The drainage plane layer can be housewrap, building paper, asphalt 

impregnated felt, or taped insulated sheathing.

Care should be taken to overlap all wall layers to provide an exit 

pathway for rain down and out of the building assembly as follows:

•	 Lap all materials in shingle fashion to direct water down and out, 

away from the wall assembly. 

•	 Flash all wall penetrations and interruptions (windows, decks, and 

the termination of walls at grade).

•	 Incorporate extended overhangs in the design to keep water away 

from walls and windows and to provide shade. Sizing of overhangs 

for shade is described in Chapter 5.

•	 Install gutters and kickout flashing.

•	 Back prime and back vent siding.

•	 Use housewrap.

•	 Elevate the bottom of the wall enough to prevent rain from 

splashing up on the siding.

Drainage Planes

Elevation drawings should specify building paper, housewrap, or 

taped insulating sheathing (rigid foam insulation) behind the exterior 

cladding to serve as a drainage plane or water-resistive barrier [2009 

and 2012 IRC R703.2] (also called a house membrane or rain barrier). 

This drainage plane can sometimes also serve as the exterior air barrier. 

None of these materials are waterproof, but they will shed rainwater 

that penetrates exterior cladding. They can prevent liquid water 

from wicking through, while remaining sufficiently vapor permeable 

(“breathable”) for outward drying (Straube 2001). 

Drainage Plane Choices 

(House Membrane or Rain Barrier)

None of these are waterproof but 

they serve to shed rainwater that penetrates 

exterior cladding while remaining vapor 

permeable. (Adapted from Straube 2001)

Building Paper is a kraft paper sheet 

impregnated with asphalt to increase 

its strength and resistance to water 

penetration. It is primarily employed as a 

drainage layer. It is graded according to a 

test of the amount of time required for a 

water-sensitive chemical to change color 

when a boat-shaped sample is floated on 

water. Common grades include 10, 20, 30, and 

60 minutes. The larger the number, the more 

resistant the paper is to water.

Building Felts have been in use for 

over 100 years. Originally made from rags, 

today’s felts are made of recycled paper 

products and sawdust. The base felt is 

impregnated with asphalt. Ratings for felt 

harken back to the traditional weight of the 

material before the oil crisis of the 1970s. At 

that time 100 square feet of the material (1 

square) weighed about 15 pounds. Modern 

#15 felt can weigh from 7.5 to 12.5 pounds per 

square depending on the manufacturer.

Housewrap typically refers to specially 

designed plastic sheet materials. Housewrap 

comes in a variety of materials and can be 

perforated or non-perforated. If joints and 

connections are sealed, housewraps can 

serve as air retarders to reduce air leakage. 

Housewraps are highly resistant to tearing, 

unlike building paper. Non-perforated wraps 

tend to have higher liquid water resistance 

because the holes between plastic fibers are 

very small.

CHAPTER 8 / BUILDING AMERICA BEST PRACTICES SERIES

8.12 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Most building paper is UV-resistant, whereas housewrap UV-exposure 

limits vary. If building paper is used as a drainage plane in areas prone 

to severe storms, use two layers to increase resistance to leakage 

at fasteners and allow for more flexible installation. If felt is used, 

install it half-lapped to create two layers.

Installation is key for all types of housewraps. See the Installers Guide on 

installing housewraps in Chapter 14. During construction and operation, 

it is important that housewraps remain clean. Surface contaminants 

interfere with the wrap’s ability to hold out water. Some cladding 

can contaminate wraps if the two are in direct contact. For example, 

water-soluble extractives in wood, such as tannins and wood sugars 

in redwood and cedar, can contaminate the surface of housewraps 

and building papers. Back-priming or back-coating wood clapboards 

and trim helps to isolate the surfactants in the wood from the housewrap 

or building paper surface. Back priming is also recommended on all 

wood and cementitious cladding systems to avoid water saturation, 

migration, and potential warping and rot. Stucco should never be 

installed in direct contact with any of the plastic-based housewraps. 

Provide a drainage space to prevent wetting of the housewrap or 

use two layers of textured building paper. Apply shingle fashion and 

install a weep screed at the bottom of the wall sheathing beneath the 

first layer of housewrap (Lstiburek 2008).

Drainage Gaps

It is essential to provide an air gap or air space between cladding and 

housewraps to reduce the time liquid phase water is trapped in the 

exterior of the wall assembly. A drainage gap between wood or fiber 

cement cladding and housewraps can be provided by 1x4 furring 

strips (“cedar-breather”), contoured housewrap, or some other spacer. 

Building America recommends a gap of at least 1/6-inch behind lap 

siding and a drainage space of 3⁄4 inch between stucco and plastic 

housewraps to control liquid phase water penetration. An air gap of 

1 inch or more is needed behind brick and stone veneer [as required 

by 2009 IRC R703.7.4.2 or 2012 IRC Table R703.7.4].

Flashing 

Details should be provided for flashing for all windows and doors; 

around chimneys, wall-roof junctions; attachments (such as porches 

and decks); projections and offsets (such as bay windows); and pipes, 

vents, wiring, exterior light fixtures, and other penetrations through 

the wall. See Chapter 14 for instructions on installing window 

flashing. [Flashing should be specified in accordance with the 2009 

IRC R703.8. 2012 IRC R703.8 adds the requirement that windows be 

installed per the window manufacturer’s or flashing manufacturer’s 

(top) Taped rigid foam insulation can serve 

as a drainage plane, air barrier, and vapor 

barrier as well as a thermal boundary 

behind cladding. David Weekley Homes’ 

uses XPS rigid foam insulation that is 

taped at seams to form a drainage plane. 

Windows are pan flashed to the exterior 

of the XPS sheathing. All roof-to-wall 

transitions have flashing and kick-out 

diverters. (Photo Source: Building Science 

Corporation)

(middle) This pipe is flashed with flexible 

flashing. Housewrap is layered shingle style 

over the top edge of the flashing. 

(bottom) This display shows flashing 

covering the bottom edge of the wall 

sheathing. Housewrap is then layered 

over the top edge of the flashing. 

(Photo Source: PNNL)

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CHAPTER 8. BUILDING ENVELOPE SUB-ASSEMBLIES

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 8.13
instructions or, if they are not provided, that pan flashing must be 

installed at the sill of exterior window and door openings to direct 

water outside.] Additional guidance can be found in the EEBA 

Water Management Guide (Lstiburek 2006a) and ENERGY STAR 

Qualified Homes Version 3 Water Management System Builder 

Checklist (EPA).

Drain all water away from the structure

(Figure adapted from Building Science Corporation)

➊ Brick veneer/stone veneer/

ship-lapped siding

➋ Drainage cavity

➌ Exterior rigid insulation – extruded 

polystyrene, expanded polystyrene, 

rigid fiberglass

➍ Housewrap, membrane, trowel-on, 

or spray-applied drainage plane; air 

barrier; and vapor retarder.

➎ Non-paper-faced exterior gypsum 

sheathing, plywood, or oriented strand 

board (OSB)

➏ Insulated wood stud cavity

➐ Gypsum board

➑ Latex paint or vapor semi-permeable 

textured wall finish. No vapor barrier 

(no polyethelene sheeting, no vinyl 

wallpaper)

This assembly can work in all climates 

except extreme cold. The house wrap 

serves as the drainage plane. The air 

barrier can be the interior gypsum 

wall, the exterior gypsum wall, or the 

rigid foam. For other wall profiles, 

see Lstiburek 2009a. (Figure Source: 

Adapted from Lstiburek 2009b).

VAPOR PROFILE

➊ ➋➌➍ ➎ ➏ ➐ ➑

Drain Site

Drain Roof

Drain Building

Drain Site

Drain Wall Drain Materials

Drain Components

Drain Openings

CHAPTER 8 / BUILDING AMERICA BEST PRACTICES SERIES

8.14 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Controlling Water Vapor in Walls

As discussed in Chapter 6, most vapor transmission through 

building assemblies is via air flow so stopping air leaks is an 

important way to prevent water vapor from getting into walls. Water 

vapor can also move via diffusion. Vapor pressure moves water 

vapor from indoors to outdoors during cold-dry weather and from 

outdoors to indoors during hot-humid weather. Water vapor that is 

trapped in walls or condenses in walls due to temperature differences 

can cause moisture problems like mold. Vapor retarders will stop 

this vapor diffusion.

Vapor Retarders

The 2009 IRC R601.3 does not list any requirement for vapor retarders 

in the hot-humid or mixed-humid climates (IECC Climate Zones 1, 2, 

3, and non-Marine 4). In the 2012 IRC, the vapor retarder discussion 

was moved to Section R702.7 but no requirement was added for vapor 

retarders in the hot-humid or mixed humid climates. See Chapter 6 

for more about vapor retarders. 

Building scientists generally do not recommend putting a vapor 

retarder in walls in the mixed-humid climate. In the mixed-humid 

climate, walls should be able to dry to both the interior and exterior.

Thus, the exterior assembly might include structural rigid foam 

sheathing taped at the seams to serve as an air flow retarder and 

drainage plane between the framing and lap siding or between the 

masonry and stucco. Interior building components should be vapor 

permeable. For example if batt wall insulation is used, it should be 

unfaced. Vinyl wall paper should not be used on exterior walls and 

paints should be latex not oil-based. Extra attention should be given 

to making sure the exterior air barrier is continuous. Using supply 

ventilation to maintain the interior of the home at a slight positive 

air pressure with conditioned air will also discourage the infiltration 

of hot-humid air. (See ventilation discussion in Chapter 9; see also 

Lstiburek 2005).

Drainage Spaces

Cladding should have a drainage space behind it of 1 or 2 inches 

for brick and stone veneer, 3/4 inch for stucco, and 1/16 inch for 

siding. Bricks and other masonry absorb water from precipitation 

and irrigation. Solar energy will then drive this moisture in the form 

of vapor into the wall assembly. The 1-inch gap [as required by

2009 IRC R703.7.4.2 and 2012 IRC Table R703.7.4] allows the vapor to 

dissipate before entering the wall cavity. An air space stops capillary 

movement of moisture, discourages vapor diffusion, stops the 

contamination of the drainage plane via contact with the cladding, 

Windows

One critical point of concern is water 

leakage around windows. The EEBA Water 

Management Guide (Lstiburek 2006a) 

offers examples of many window flashing 

applications. See Chapter 14 for detailed 

examples of window flashing for homes 

with housewrap and plywood or OSB 

sheathing. Window and door flashing 

details should be designed to match 

specific wall assemblies and claddings. 

Flashing systems should be designed in 

accordance with ASTM Standard E2112-

07, “Standard Practice for Installation of 

Exterior Windows, Doors, and Skylights” 

(ASTM 2007).

Vapor Retarder Recommendations: 

•	 Design walls to dry to the interior or

both the interior and exterior.

•	 Avoid use of a less permeable vapor

retarder where a more permeable 

retarder will provide satisfactory 

performance, to encourage drying.

•	 Avoid installing vapor barriers on both

sides of assemblies, i.e., double vapor 

barriers, to facilitate assembly drying in 

at least one direction.

•	 Avoid installing Class I vapor barriers

(polyethylene sheet, foil-faced batt) on 

the interior of air conditioned assemblies.

•	 Avoid vinyl wall coverings on the inside

of air conditioned assemblies.

(Source: Lstiburek 2006c) 

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CHAPTER 8. BUILDING ENVELOPE SUB-ASSEMBLIES

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 8.15
and allows air circulation for better drying. In some wall assemblies, 

ventilation openings to the exterior at both the top and bottom 

further encourage drying. See Straube (2009b) for information about 

the performance of drainage spaces with different wall types.

Dry Building Materials

Building with wet or green materials can be a source of vapor in 

walls. Damp lumber should be allowed to dry before use to less 

than 18% moisture content or as required by local code. The Forest 

Products Laboratory recommends 12% mositure content (FPL 

2010). Interior relative humidity should be kept to less than 50% 

during the cooling season.

Air Sealing

Water vapor is far more likely to be transported into walls by air 

movement than by diffusion. Therefore, air sealing is an important 

method for preventing water vapor movement into walls. Air sealing is 

further described in the next section. 

Controlling Air Infiltration in Walls

The 2009 IECC 402.4 requires that the building thermal envelope be 

durably sealed to limit infiltration and specifies that the following areas 

should be caulked, gasketed, weather-stripped or otherwise air sealed: 

all joints, seams, and penetrations; site-built windows, doors, and 

skylights; window and door openings; utility penetrations; dropped 

ceilings or chases on exterior walls; knee walls; walls and ceilings 

separating a garage from the conditioned space; behind tubs and 

showers on exterior walls; common walls between dwelling units; attic 

access openings; rim joist junctions; and other sources of infiltration. 

These air sealing items are listed in the 2012 IECC in Table R402.4.1.1. 

The 2009 IECC allows for air leakage to be tested with a blower door 

or visual inspection. The 2012 IECC R402.4.1.2 requires that air leakage 

be tested with a blower door test, to confirm that air leakage does not 

exceed 5 air changes per hour at 50 Pascals in IECC climate zones 1 and 

2, or 3 ACH at 50 Pa in climate zones 3-8. To be effective the air barrier 

must be continuous, meaning that it extends over the entire envelope 

of the structure, although it may be made up of many materials. 

Indicate on plans the methods, materials, and locations where sealing 

is needed to form the house air-pressure barrier.

A comprehensive air-sealing strategy begins with indicating on the 

house plans the location of the conditioned space by outlining the 

building envelope. The plans should show the location of complex 

details like chases, stairwells, dropped ceilings, fireplace penetrations, 

balconies, and knee walls, so that they can easily be identified as 

(top) When rigid foam insulation is applied 

to the exterior side of the wall cavity under 

the cladding, with seams taped and an air 

gap provided, it acts as a vapor barrier, 

preventing moisture in brick and stucco 

finishes from being driven inward during 

drying. It also serves as an air barrier and 

rain screen. (Photo Source: S+A Homes)

(middle) Window flashing is overlapped to 

provide a continuous drainage plane.

(bottom) Water should not be directed 

to flow into the wall. This could soon lead 

to water intrusion inside the wall.

CHAPTER 8 / BUILDING AMERICA BEST PRACTICES SERIES

8.16 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Exterior Air Barrier with Rigid Foam Sheathing – Points to Seal

Interior Air Barrier – Points to Seal Interior vs. Exterior Air Barrier 

(see house figures at right) Air sealing is 

needed on the top, bottom, and sides of 

the house to ensure an airtight shell. The 

house on top uses a conventional approach 

where the interior drywall and subfloor 

serve as the air barrier. Every hole through 

these surfaces (for wiring, pipes, etc.) 

must be caulked. The house on the bottom 

uses external rigid foam sheathing, which 

provides a continuous air barrier with fewer 

air sealing steps. Foam sheathing can also 

serve as a drainage plane, vapor barrier, 

and thermal barrier. (Detailed drawings are 

in Chapter 14.) 

8.17

CHAPTER 8. BUILDING ENVELOPE SUB-ASSEMBLIES

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 8.17
being inside or outside the conditioned space. The plans also should 

show where insulation and draft stopping should be installed. 

If the air barrier will be on the interior side of the walls, it is 

important to specify that all drywall joints be caulked, mudded, and 

taped. To ensure an airtight envelope when the air barrier is on the 

inside of the building envelope, builders should address the following 

common sources of air leakage through walls:

•	 Insulate and air seal behind tubs and shower stalls on the exterior 

walls by filling the wall cavity with insulation, and then installing 

and sealing rigid sheathing material on the interior surfaces of the 

wall before the tub or shower is installed. 

•	 Line fireplace enclosure framing with rigid sheathing material, 

like gypsum board, plywood, wafer board, or foil-covered pressed 

paper, and seal edges to box in sides, top, and bottom of fireplace 

enclosure. Wood-burning fireplaces should have gasketed doors 

and outdoor combustion air [per 2009 IECC 402.4.3; 2012 IECC 

Table R402.4.1.1].

•	 Use blocking material to airseal floor joists under cantilevered 

floors and kneewalls and behind staircases on exterior walls.

•	 Air seal chimney chases and around the chimney flue where it 

penetrates the ceiling using sheetmetal and heat-resistant caulk.

•	 Box in tops and ends of soffits and dropped ceilings with sheathing 

that is caulked to framing on all edges.

•	 Fill in the rough opening around windows and doors with foam, 

caulk, or backer rod.

•	 Apply housewrap and flashing as shown in Chapter 14.

•	 Caulk, foam, or seal with gaskets all penetrations for electrical 

boxes, outlets, switches, and plumbing.

Alternatively, the air barrier can be placed on the outside of the 

building envelope. One method for doing this is to install rigid 

foam on the exterior side of the wall under the cladding. This foam 

sheathing can provide a continuous air barrier when all seams are 

taped and caulked. This exterior air-barrier system can also help 

control wind washing. 

For occupant health and safety, builders should pay close attention 

to sealing shared walls and ceilings between attached garages and 

living spaces. When the garage is attached to the house, the gaps 

created by joists spanning both conditioned space and the garage 

Wood or rigid foam filler blocking is 

cut to fit the gaps between floor joists 

and caulked or foamed in place to form 

an air break between conditioned and 

unconditioned spaces.

Attic access panel air sealing

Garage common wall air sealing

Cladding should have a 

drainage space behind it: 

• 1 inch for brick [2009 IRC R703.7.4.2]

• 3/4 inch for stucco, and

• 1/16 inch for siding.

Tape

Bottom plate caulked

or gasketed to subfloor

Use rigid foam 

or sheet goods to 

seal joist cavities

Seal

Hardboard

Seal

HOUSEWRAP

HOUSEWRAP

HOUSEWRAP

HOUSEWRAP

Before installing 

the window, caulk 

the outside edges 

of the head and 

side jambs

Do not caulk

across the sill

CAULK

CAULK

Seal gap between 

window and rough

opening on interior

Recessed light fixtures 

should be rated for 

Insulated Ceiling Air 

Tight (ICAT).

AIR TIGHTNESS 

LABEL

Airtight wire 

connection from 

junction jox

Airtight

can

Decorative

cover Caulk

or Gasket

Sealant

Support sheathing

Electrical

panel

Seal wire

connection

Nailing

flange Built-in

sealant

Flange for sealing to 

drywall air barrier

Select boxes with 

built-in gasket 

and sealant

Seal

Solid air barrier

material sealed at 

parimeter and seams

CAULK

Air seal gasket

between trim

and panel

Rigid insulation

Attic

Use ENERGY STAR

labeled door

Install automatic

closer and gasket

or weatherstripping

Baseplate sealed 

to subfloor

Blocking between joists,

sealed at perimenter

Insulation in permanent

contact with subfloor

Air seal gasket

REGISTER

Seal boots to 

sheet goods with 

caulk, mastic, or 

spray foam

Tape

Sill gasket

Use ENERGY STAR

labeled door

Install automatic

closer and gasket

or weatherstripping

Baseplate sealed 

to subfloor

Blocking between joists,

sealed at perimenter

Insulation in permanent

contact with subfloor

Air seal gasket

Crawlspace

Rigid insulation

REGISTER

Seal all joints in 

boot and elbow

with mastic

Seal boots to 

sheet goods with 

caulk, mastic, or 

spray foam

Bottom plate caulked

or gasketed to subfloor

Drywall caulked, glued 

or gasketed; inside seam 

taped and mudded

GARAGE

Bottom plate caulked

or gasketed to subfloor

 on interior, exterior,

or both surfaces

Drywall caulked, 

glued or gasketed 

to top plate on interior, 

exterior, or both surfaces 

CAVITY

Solid air barrier

material sealed

at perimeter

CAULK

Use caulk or adhesive to

seal panels to joists at seams

CHAPTER 8 / BUILDING AMERICA BEST PRACTICES SERIES

8.18 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
INTERIOR - 

Using gypsum and flooring

EXTERIOR - 

Using rigid foam sheathing

must be blocked off and sealed. Creating air barriers to close gaps 

between the garage and the conditioned space is more difficult with 

irregularly shaped joists, such as I-joists and web-trusses. A simple 

solution is to plan ahead and align the ends of the joists with the 

wall adjoining the conditioned space to allow for end blocking.

Envelope Air Sealing

(Figure Source: Building Science Corporation)

Gaps between the garage and conditioned 

space are properly sealed by carefully 

cutting and then caulking wood 

sections to fit between trusses. 

(Photo Source: EPA 2008)

8.19

CHAPTER 8. BUILDING ENVELOPE SUB-ASSEMBLIES

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 8.19
Controlling Heat Flow in Wall Assemblies

The control of heat flow in the building is managed by the type, 

thickness, location, and proper installation of insulation. The 2009 

IECC Table 402.1.1 requires a wall R value of R-13 for wood-framed 

walls for IECC climate zones 3 and 4. For mass walls (concrete 

block, concrete, ICF, brick, etc.), the requirement is R-5 for climate 

zones 3 and 4. If more than half the insulation is on the interior of 

the mass wall, the requirements is R-8 for climate zones 3 and 4. In 

the 2012 IECC (Table R402.1.1), the insulation requirement increases 

for IECC climate zones 3 and non-marine 4. The requirement for a 

wood-framed wall increases to R-20 (or R-13 cavity insulation plus 

R-5 insulated sheathing) and the requirement for a mass wall increases 

to R-8 (or R-13 if more than half the insulation is on the interior). 

Window selection and design are also important. 

Consider implementing the following above-code recommendations: 

• Use advanced framing techniques to cut lumber costs and 

provide more space for insulation. Provide advanced framing 

details on plans.

• Specify that cavity walls separating conditioned and unconditioned 

spaces be insulated with high-density batt insulation, dense-packed 

fibrous insulation, or spray-applied foam.

• Specify that spray foam be used to insulate and seal rim joists.

• Specify that taped rigid foam insulating sheathing be used on 

the exterior side of studs in addition to cavity insulation. This 

sheathing eliminates thermal bridging at the studs.

• Use third-party inspectors or HERS raters to inspect insulation 

installation before dry walling.

• Specify ENERGY STAR-labeled doors.

• Design roofs and overhangs to shade and protect windows, doors, 

and walls.

Masonry walls may be finished with stucco, wood, or other claddings. 

Best practices to improve thermal efficiency include the following: 

• Semi-vapor permeable rigid insulation should be installed on the 

interior or exterior of wall assemblies and should be unfaced.

• Wood furring should be installed over rigid insulation. The rigid 

insulation should be continuous over the surface of the wall, 

except for a 2x4 furring at the intersection with the ceiling. This 

blocking attaches directly to the masonry block and serves as a 

draft and fire stop. The rigid insulation abuts the blocking but does 

Rigid foam insulates the interior of 

masonry walls behind the fireplace in this 

Building America home by Castle and 

Cooke in Winter Garden, Florida.

(Photo Source: BAIHP)

Code/Above Code 

Wall Insulation Above Grade

Code Requirements found in 2009 IECC and 

2012 IECC Table R402.1.1

Code

2009 IECC Wood 

Framed Mass Wall***

IECC CZ 3 R-13 R-5/R-8

IECC CZ 4 R-13 R-5/10

2012 IECC Wood 

Framed Mass Wall***

IECC CZ 3 R-20/

R-13+R-5** R-8/R-13

IECC CZ 4 R-20/

R-13+R-5** R-8/R-13

Above Code

ENERGY STAR 

Version 3.0

Insulation levels shall meet 

or exceed 2009 IECC 

levels and achieve Grade 

1 installation per RESNET 

standards.

*The second R value applies when more than half the 

insulation is on the interior of the mass wall.

**R-13 cavity insulation + R-5 Rigid foam sheathing.

CHAPTER 8 / BUILDING AMERICA BEST PRACTICES SERIES

8.20 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
not cover it or extend behind it. Foam seal or caulk all top plate 

penetrations and exterior wall penetrations. 

• Use pressure-treated lumber to frame out sub-jambs and 

spacers within window and door rough openings.

• As with other walls, penetrations to the exterior or through top 

and bottom plates should be foam sealed or caulked. Also air seal 

penetrations to garages and porches.

• Mud, tape, and caulk seams and corners of gypsum board and use 

sill sealer at top plates and bottom plates to control air leakage 

through the walls.

• When pouring the slab, take care to create a seat in the concrete 

to accept the block and seats in the concrete to act as drain pans 

where exterior doors and sliding doors will be located. 

Roof Assemblies

Controlling Liquid Water in Roof Assemblies

Roof and wall assemblies must contain surfaces that will drain 

water in a continuous manner down and off the building. Water 

must have a path that will take it from its point of impact, around 

any elements, such as chimneys, windows, doors, and seams, all 

the way to the exterior ground, and away from the house. Consider 

implementing the following recommendations: 

•	 Properly flash valleys and roof edges [2009 and 2012 IRC R703.8; 

R903.2].

•	 Size gutters and downspouts to accommodate anticipated 

storms. Show gutter sizes on elevations and specify sizes in 

construction documents.

•	 Provide downspout drainage to carry water at least 3 feet 

beyond the building.

•	 Use kick-out diverters properly integrated with flashing to direct 

water away from the side of the house [2009 and 2012 IRC R703.8, 

R903.2].

•	 In areas with potentially high winds and heavy rains, install 4-inch to 

6-inch “peel and seal” self-adhering water-proofing strips over joints 

in roof decking before installing the roof underlayment and cover.

•	 Keep roof geometry simple. The more complex the roof—the more 

dormers, ridges, and valleys—the more likely the roof will leak. 

(A) Deluging rains in the hot-humid climate 

can overwhelm gutters. Improper flashing 

can allow water into walls, causing significant 

damage. (B) Improvised deflectors that are 

improperly integrated into the wall flashing 

and gutter are rarely sized to handle the 

volume of water that can run off the roof in 

a large downpour and they may contribute 

to water entry into the wall. (C) To keep the 

water out, flashing should be integrated with 

the house wrap, siding, and shingles or roof 

tiles and (D) the diverter should be seamless 

and adequately sized to direct all of the water 

volume away from the wall and into the gutter. 

See Chapter 14 for details. (Photo Sources: A, 

C, D - DryFlekt Products, Inc., B - Steve Easley)

A

B

C

D

8.21

CHAPTER 8. BUILDING ENVELOPE SUB-ASSEMBLIES

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 8.21
Controlling Water Vapor in Roof/Attic Assemblies

While ventilation and an interior vapor retarder are recommended to 

deal with water vapor in cold climates, most of which is coming from 

inside the home, in the mixed-humid climate, the greatest source of 

water vapor during warm months is hot, humid outside air. 

Moisture in attics has traditionally been addressed with ventilation 

by providing soffit, ridge, and/or gable vents at a ratio of typically 

1:300 free vent area to insulated ceiling area. However, with the 

complex roof designs of modern homes where attics are blocked 

by dormers, hips, skylights, cathedral sections, etc., it is difficult 

to achieve adequate cross ventilation. In vented cathedral ceiling 

assemblies, a minimum 2-inch clear airspace is recommended 

between the underside of the roof deck and the top of the cavity 

insulation (Lstiburek 2006d). In a vented attic, the air barrier is 

provided by the ceiling gypsum. Latex paint provides an adequate, 

Class III vapor retarder because the primary transport mechanism 

for vapor is air movement, which is stopped by ceiling drywall if it 

is adequately sealed at all penetrations. Class I and Class II vapor 

retarders are not recommended in vented attic assemblies in IECC 

climate zones 1-5 due to the potential for top side condensation in 

summer months during air conditioning periods (Lstiburek 2006d). 

Unvented attics are another option that is recommended. A sealed 

attic reduces the infiltration of hot, humid outside air into the home, 

provides a conditioned space for HVAC and ducts, increases structural 

resistance to high winds, increases fire resistance by limiting air supply 

(Rudd 2003), reduces infiltration of wind-driven rain, and provides 

conditioned storage. The key to moisture control in an unvented roof 

assembly is to keep the condensing surface, the underside of the roof 

deck, sufficiently warm throughout the year to prevent condensation 

or to prevent interior moisture-laden air from accessing it. The local 

climate may be warm enough year-round that the roof deck stays 

warm or rigid insulation can be installed above the roof deck. Or, to 

keep humid air from touching the underside of the roof deck, it can be 

sprayed with air-impermeable spray foam insulation (Lstiburek 2006d).

Controlling Air Flow in Roof/Attic Assemblies

The ceiling is air sealed with techniques similar to those used for the 

walls including mudding and taping of dry wall seams and caulking 

of cracks. The 2009 IECC 402.4 requires that the building thermal 

envelope be air sealed, including all joints, seams, and penetrations; 

dropped ceilings; knee walls; walls and ceilings separating a garage 

from conditioned space; attic access openings; rim joist junctions; 

and other sources of infiltration. The 2012 IECC lists air sealing 

requirements in Table R402.4.1.1.

Baffles allow ventilation under roof decking 

while keeping wind from blowing insulation 

back from the edges of an attic.

Code/Above Code 

Ceiling Insulation

Code Requirements found in 2009 IECC 

and 2012 IECC Table R402.1.1

Code 2009 IECC 2012 IECC

IECC CZ 3 R-30 R-38*/

**

IECC CZ 4 R-38 R-49

Above Code

ENERGY STAR 

Version 3.0

Insulation levels shall meet 

or exceed 2009 IECC 

levels and achieve Grade 

1 installation per RESNET 

standards. Radiant barrier or 

ENERGY STAR roof product 

are required if more than 10 

feet of ductwork is located in 

an unconditioned attic.

 * R-30 if cathedral but cathedral must be 

limited to 500 ft2 or 20% of total insulated 

ceiling area, whichever is less.

**R-30 permitted if raised heel trusses used.

CHAPTER 8 / BUILDING AMERICA BEST PRACTICES SERIES

8.22 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Air sealing details to consider include:

•	 Provide details on plans for air sealing and insulating complex 

structures like kneewalls, gable windows, porch-attic interfaces, 

and cathedral ceilings. 

•	 Seal all penetrations and seams in ceiling gypsum board so that 

it functions as a continuous air barrier. 

•	 Draft-stop soffits with rigid air barrier caulked at seams. 

•	 Gasket or weather strip attic access hatches or doors and insulate 

to ceiling insulation depth [as required by 2009 IECC 402.2.3; 2012 

IECC 402.2.4]. 

•	 Install recessed lighting fixtures that are airtight insulation-contact 

(IC) rated, and caulk or gasket the housing to the ceiling drywall 

[per 2009 IECC 402.4.5; 2012 IECC 402.4.4].

•	 Provide a weather-stripped cover for whole-house fans.

•	 Ensure that windows, doors, and skylights have a labeled 

infiltration rate of no more than 0.3 cfm/ft2

 [per 2009 

IECC 402.4.4; 2012 IECC 402.4.3].

Controlling Heat Flow in Roof/Attic Assemblies

Maintaining the insulation level throughout the entire plane of the 

ceiling and over the top of the perimeter walls is key to controlling 

heat flow through the attic. Raised-heel energy trusses allow the 

thickness of the ceiling insulation to be maintained above the top 

plates of the exterior wall framing. Baffles should be installed at 

each rafter bay to prevent wind washing of thermal insulation 

and to prevent insulation from blocking ventilation in vented roof 

assemblies. [See the ceiling insulation table above for 2009 and 2012 

ceiling insulation requirements. Also see 2009 and 2012 IECC Table 

402.1.1 and sections 402.2.1 and 402.2.2.]

Research by Building America research partner the Florida Solar 

Energy Center showed that sealed attic construction with an R-19 

spray-foam-insulated roof deck would reduce cooling energy 

consumption by 6% to 11% and lower attic temperatures to an 

average of 83°F compared to 110°F for the control home 

(Parker et al. 2002).

Two Building America builders in the hothumid climate chose to insulate their attics 

by spray foaming the underside of the roof 

decking providing an insulated conditioned 

space for HVAC. Green Coast Enterprises 

(top) chose high-density closed-cell spray 

foam for its homes in New Orleans. Imagine 

Homes chose low-density spray foam 

for its attics.

8.23

CHAPTER 8. BUILDING ENVELOPE SUB-ASSEMBLIES

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 8.23
Traditional roof trusses pinch insulation 

where the roof meets the walls

Raised heel or energy trusses allow 

even the corners of the attic to be well 

insulated; this helps to prevent ice dams 

in winter and keeps rooms cooler in 

summer. 

Some builders use cantilevered trusses 

to get full height insulation over the 

exterior wall. 

For More Information on Moisture, Air, 

and Heat Flow Control in Walls and Roofs

2009 IECC. 2009. International Energy Conservation Code, Section 402.4 “Air Leakage,” 

International Code Council (ICC), Washington, D.C. www.iccsafe.org/Store/Pages

2009 IRC. 2009. International Residential Code - One and Two-Family Dwellings, 

International Code Council (ICC), Washington, D.C. www.iccsafe.org/Store/Pages

ASTM. 2007. Standard Practice for Installation of Exterior Windows, Doors, and Skylights. 

www.astm.org/Standards/E2112.htm

Buildernews Magazine. May 2004, “Housewrap Felt or Paper: Comparing specs on weather barriers”

Building Science Corporation. Homeowner Information Resources.

www.buildingscienceconsulting.com/resources/homeowner.htm

Building Science Corporation. 2006. Info-500: Building Materials Property Table, Building Science 

Corporation, April 16, 2010, www.buildingscience.com/documents/information-sheets/5-

thermal-control/building-materials-property-table

DeKorne Clayton. 2006. “Stucco that Works.” Coastal Contractor Online, 

www.coastalcontractor.net/article/94.html

DOE. “Vapor Barriers and Vapor Diffusion Retarders.” Energy Savers Fact Sheet, 

www.energysavers.gov/your_home/insulation_airsealing/index.efm/mytopic=11810

DOE. 2000. Technology Fact Sheet on Weather-Resistive Barriers. Prepared by NAHB 

Research Center, Southface Energy Institute, and Oak Ridge National Laboratory for the 

U.S. Department of Energy, DOE/GO10099-769, www.toolbase.org/PDF/DesignGuides/

weatherresistantbarriers.pdf

DOE. 2009. Moisture Control in Walls, Energy Savers, 

www.energysavers.gov/your_home/insulation_airsealing/index.cfm/mytopic=11800?print

ENERGY STAR. 2008. Thermal Bypass Checklist Guide www.energystar.gov/ia/partners/

bldrs_lenders_raters/downloads/TBC_Guide_062507.pdf

FEMA. 2009. Designing for Flood Levels Above the BFE. Federal Emergency Management 

Agency, www.fema.gov/library/file?type=publishedFile&file=757_apd_3designabovebfe_rev1.

pdf&fileid=388b4fb0-34e6-11de-baca-001185636a87

Forest Products Laboratory. 2010. Wood Handbook, FPL-GTR-190, Forest Products 

Laboratory, U.S. Department of Agriculture, www.fpl.fs.fed.us/products/publications/

several_pubs.php?grouping_id=100&header_id=p

Gatland, S. D., Karagiozis, A. N., Murray, C., and Ueno, K. 2007. “The Hygrothermal 

Performance of Wood-Framed Wall Systems Using a Relative Humidity-Dependent Vapor 

Retarder in the Pacific Northwest,” in Thermal Performance of the Exterior Envelopes of 

Buildings X, proceedings of ASHRAE THERM X, Clearwater, Florida, 

www.ornl.gov/sci/roofs+walls/staff/papers/148.pdf

IBACOS. 2002. “Moisture Issues in Homes with Brick Veneer” 

www.eere.energy.gov/buildings/building_america/pdfs/db/36397.pdf

Lstiburek, Joseph. 2004a. EEBA Builders Guides. Guides to mixed humid, hot-dry, mixeddry, and cold climates, www.eeba.org/bookstore. 

Lstiburek, Joseph. 2004b. Roof Design, Research Report 0404, Building Science 

Corporation, www.buildingscience.com/documents/reports/rr-0404-roof-design.

Lstiburek, Joseph. 2006a. EEBA Water Management Guide, available for purchase at 

www.eeba.org/bookstore/prod-Water_Management_Guide-9.aspx 

Lstiburek, Joseph. 2006b. Understanding Drainage Planes, BSD 105, October 24, 2006, 

Building Science Corporation, www.buildingscience.com/documents/digests/bsd-105-

understanding-drainage-planes/

Lstiburek, Joseph W. 2006c. Understanding Vapor Barriers, BSD 106, Building Science Press, 

www.buildingscience.com/documents/digests/bsd-106-understanding-vapor-barriers

CHAPTER 8 / BUILDING AMERICA BEST PRACTICES SERIES

8.24 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Lstiburek, Joseph. 2006d. Understanding Attic Ventilation, BSD-102, Building Science 

Corporation, October 27, 2006, www.buildingscience.com/documents/digests/bsd-102-

understanding-attic-ventilation/

Lstiburek, Joseph. 2008. Problems with Housewraps, RR 0106, Building Science 

Corporation, www.buildingscience.com/documents/digests/bsd-013-rain-control-inbuildings

Lstiburek, Joseph. 2009 a. Moisture Control for New Residential Buildings, BSD-012, 

Building Science Corporation. www.buildingscience.com/documents/digests/bsd-012-

moisture-control-for-new-residential-buildings?topic=doctypes/digests

Lstiburek, Joseph. 2009b. “The Perfect Wall,” Building Science Insight 001, 

May 21, 2009, Building Science Corporation, www.buildingscience.com/documents/insights/

bsi-001-the-perfect-wall

Lstiburek, Joseph. 2011. “Dam Ice Dam,” Insight 046, February 2011, Building Science 

Corporation, www.buildingscience.com/documents/insights/bsi-046-dam-ice-dam/

NAHBRC. Moisture Protection of Wood Sheathing, National Association of Home Builders 

Research Center, www.toolbase.org.PDF/DesignGuides/MoistureProtectionWoodSheathing.pdf

NWPCC. 2010. Energy Efficiency: Appendix F: Model Conservation Standards, Council 

Document 2010-03, Northwest Power and Conservation Council, www.nwcouncil.org

Parker, D., J. Sonne, and J. Sherwin. 2002. “Comparative Evaluation of the Impact of 

Roofing Systems on Residential Cooling Energy Demand in Florida,” Proceedings of ACEEE 

2002 Summer Study, American Council for an Energy Efficient Economy, August 2002, 

Prepared by the Florida Solar Energy Center, www.fsec.ucf.edu/en/publications/html/FSECCR-1220-00/index.htm

Rudd, Armin. 2003. Roof and Attic Ventilation Issues in Hot-Humid Climates, RR-0302, 

Building Science Corporation, www.buildingscience.com/documents/reports/rr-0302-roofand-attic-ventilation-issues-in-hot-humid-climates

Straube, John. 2001. “Wrapping it Up,” Canadian Architect, May 2001, 

www.cdnarchitect.com/issues/ISarticle.asp?aid=1000115982

Straube, John. 2009a. Rain Control in Buildings, BSD 013, August 10, 2009, Building Science 

Corporation, www.buildingscience.com/documents/digests/bsd-013-rain-control-inbuildings?full_view=1 

Straube, John. 2009b. RR-0907 Ventilated Wall Claddings: Review, Field Performance, 

and Hygrothermal Modeling, Building Science Corporation www.buildingscience.com/

documents/reports/rr-0907-ventilated-wall-claddings-review-performance-modeling/view

University of Illinois Extension Office. “Five Steps to a Healthier Garage.” 

http://web.extension.uiuc.edu/will/factsheets/family116.html

Window and Door Assemblies

Choosing highly efficient windows will add expense to your project 

but will increase comfort, durability, and energy savings. The National 

Fenestration Rating Council (www.nfrc.org) provides window labeling 

that includes the following performance information:

•	 U-factor measures heat transfer—the lower the U-factor, the better 

the window performs at stopping heat flow. U-factors are the inverse 

of R-values, which measure a material’s insulation effectiveness. 

U-factor values for windows generally fall between 0.20 and 1.2.

• Solar heat gain coefficient (SHGC) measures how well the window 

blocks heat caused by sunlight—the lower the SHGC rating, the 

Example of a window label from the 

National Fenestration Rating Council 

and ENERGY STAR.

Code/Above Code 

Window U Factor and 

Solar Heat Gain Coefficient 

A comparison of the 2009 IECC and 2012 

IECC Climate Zone 3 and 4 Requirements and 

Building America Recommendations

Code U-Factor SHGC

2009 

IECC

2012 

IECC

2009 

IECC

2012 

IECC

CZ 3 0.5 0.35 0.30 0.25

CZ 4 0.35 0.35 NR 0.40

Above Code

ENERGY 

STAR 

Version 

3.0

U-Value: 

CZ 3 - ≤0.60

CZ 4 - ≤0.32 

SHGC:

CZ 3 - 0.30

CZ 4 - 0.40 

8.25

CHAPTER 8. BUILDING ENVELOPE SUB-ASSEMBLIES

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 8.25
less solar heat the window transmits. This rating is expressed as a 

fraction between 0 and 1. The 2009 and 2012 IECC Table 402.1.1 lists 

U-factor and SHGC requirements. See the table on page 8.25 for 

U-factor and SHGC requirements for IECC climate zones 3 and 4.

• Visible transmittance (VT) measures how much light comes 

through a window. VT is expressed as a number between 0 and 1

—the bigger the number, the more clear the glass.

• Air leakage through a window assembly (AL rating) is expressed 

as the equivalent cubic feet of air passing through a square foot 

of window area (cfm/ft2

)—the lower the AL, the less the window 

leaks. A typical rating is 0.2. Per the 2009 IECC 402.4.4 (2012 IECC 

402.4.3), windows, skylights, and sliding glass doors should have 

an air-infiltration rate of ≤ 0.3 cfm/ft2

 and swinging doors of 

≤ 0.5 cfm/ft2

.

ENERGY STAR qualifies windows based on climate zones and 

divides the United States into four climate zones. See the charts and 

map below for U-factor and SHGC guidelines by climate.

The DOE-sponsored Efficient Windows Collaborative operates 

a website that can help designers and consumers choose windows 

(www.efficientwindows.org/index.cfm). The website includes a tool 

that allows users to analyze energy costs and savings for windows with 

different ratings. The website also has fact sheets with comparisons 

for each state.

ENERGY STAR Qualified Windows, Doors, and Skylights 

Eligibility Criteria (Version 5.0, 04/07/2009, effective 01/04/2010)

For More Information on 

Windows and Doors

AAMA. 2011. “International Code Requirements 

for Windows and Doors.” American Architectural 

Manufacturers Association, accessed 9-12-2011, 

www.windowanddoor.com/article/codesstandards/international-code-requirementswindows-doors

American Architectural Manufacturers 

Association. “Product Certification – 

Search now for AAMA-Certified Products 

(windows and doors).” Available at 

www.aamanet.org/general.asp?sect=2&id=127 

ASTM. ASTM E2112 - 07. Standard Practice for 

Installation of Exterior Windows, Doors and 

Skylights, www.astm.org/Standards/E2112.htm 

Carmody, John, Stephen Selkowitz, Dariush 

Arasteh, and Lisa Heschong. 2000. 

Residential Windows: A Guide to New 

Technologies and Energy Performance. 

W.W. Norton & Company, Inc., New York. 

ENERGY STAR Efficient Windows Collaborative

www.efficientwindows.org/energystar.cfm 

ENERGY STAR. Residential Windows, Doors, 

and Skylights. www.energystar.gov/index.

cfm?c=windows_doors.pr_windows 

FMA/AAMA 100-07. “Standard Practice for 

the Installation of Windows with Flanges or 

Mounting Fins in Wood Frame Construction.” 

Available from AAMA’s online store at 

www.aamanetstore.org/pubstore/

ProductResults.asp?cat=0&src=100

Insulating Glass Manufacturers Alliance.

www.igmaonline.org/content.php?doc=142

National Fenestration Rating Council.

www.nfrc.org

CHAPTER 8 / BUILDING AMERICA BEST PRACTICES SERIES

8.26 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
A home’s mechanical systems can have a significant impact on 

its energy performance and comfort. As envelope performance 

improves, these systems are becoming more important targets for 

improved efficiency. The charts below show typical energy usage for 

the equipment described in this chapter, including HVAC (heating, 

ventilation, and air conditioning), plumbing and water heating, 

lighting, and appliances. 

Heating and Cooling

Using Building America 

best practices for insulation, 

windows, and air sealing 

can improve building 

envelope performance to 

such an extent that HVAC 

system size can sometimes 

be reduced and still meet 

occupant comfort needs. 

Builders may be surprised 

to find that properly sizing 

the HVAC system increases 

comfort while providing 

a remarkable opportunity 

for dollar savings in highperformance homes.

Chapter 9.

Mechanical, Plumbing, 

and Electrical Systems

High-efficiency, sealed-combustion HVAC 

equipment increases savings and works well 

with the tighter building envelope of Building 

America homes. (Photo Source: BSC)

CHAPTER TOPICS

9.1 Heating and Cooling

9.10 Ducts and Air Handlers

9.15 Ventilation

9.19 Plumbing and Water Heating

9.25 High-Performance Lighting

9.27 Appliances

Typical Residential On-Site 

Energy Consumption by End 

Use in the United States

(Figure source: DOE. 2008 Buildings 

Energy Data Book, based on delivered 

energy end-uses for an average U.S. 

household.)

0

50

100

150

200

250

300

Annual Source Energy Consumption (Mbtu/yr)

Appliance & Misc.

Lighting

Cooling

Heating

Hot Water

Benchmark 40%

A comparison of energy usage by end use for a home built to the 

Building America benchmark and a home built to the 40% energy 

savings target in the mixed-humid climate. Example based on a 

2,140 ft2

-house in Seaford, Delaware. Analysis by IbACOS.

44.3%

15.9%

7.9%

15.5%

7%

4.4%

Cooling

Water Heating

Lighting

Refrigeration

Other 

Appliances

& Electronics

Heating

Energy End-Use

9.1

CHAPTER 9. MECHANICAL, PLUMBING, AND ELECTRICAL SYSTEMS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 9.1
For the best results in comfort, efficiency, and durability, HVAC and 

duct design must be integrated in the overall architectural design. 

Builders should work closely with their HVAC engineer to properly 

size and select the HVAC equipment, design and install ducts, and 

provide appropriate ventilation. These steps will go a long way 

toward improved energy efficiency, comfort, and cost savings. [The 

2009 and 2012 IECC 403.1 and ENERGY STAR Version 3.0 require 

that forced air furnaces come with a programmable thermostat and 

that heat pumps with electric resistance backup heat be equipped 

with controls that prevent the supplemental heater from coming on 

when the heat pump compressor can meet the load.]

Look for ENERGY STAR-qualified furnaces, heat pumps, and 

air conditioners. See the Building America HVAC guide for more 

information on selecting energy-efficient heating and cooling equipment 

(DOE 2011).

Heating and Cooling Equipment Sizing

A well-designed house should have an HVAC system properly sized 

to its demands. The Air Conditioning Contractors of America 

(ACCA) has published simple but effective methods for determining 

loads and sizing of ductwork and heating and cooling equipment 

(available for purchase at www.acca.org). 

•	 MANUAL S guides you through the 

selection of appropriate heating and 

cooling equipment to meet identified loads.

•	 MANUAL J tells you how to calculate 

heating and cooling loads. 

•	 MANUAL D tells you how to size ducts.

•	 MANUAL T gives you the basics of 

air distribution for small buildings. 

•	 MANUAL RS focuses on comfort, 

air quality, and efficiency.

The ACCA and the American National Standards Institute have 

produced several ANSI/ACCA standards on HVAC equipment 

installation and maintenance (ACCA 2010): 

•	 #4 Maintenance of Residential HVAC Systems

•	 #5 HVAC Quality installation Specification

•	 #6 Restoring the Cleanliness of HVAC Systems

•	 #9 Quality Installation Verification.

Right sizing of HVAC equipment 

using Manual J calculations can 

minimize energy use and save 

upfront costs.

Efficiency Measures for 

Air Conditioners, Heat 

Pumps, and Furnaces

Seasonal Energy Efficiency Ratio (SEER)

is a measure of equipment energy 

efficiency over the cooling season. It 

represents the total cooling of a central 

air-conditioner or heat pump (in Btu) 

during the normal cooling season as 

compared to the total electric energy 

input (in watt-hours) consumed during 

the same period. Heat pumps and air 

conditioners must have a SEER of 13 or 

higher (per Federal requirements that 

went into effect in 2006).

Heating Season Performance Factor 

(HSPF) is a measure of a heat pump’s 

energy efficiency over one heating season. 

It represents the total heating output of 

a heat pump (including supplementary 

electric heat) during the normal heating 

season (in Btu) as compared to the total 

electricity consumed (in watt-hours) 

during the same period. Heat pumps 

and furnaces must have an HSPF of 7.7 

or higher (per Federal requirements that 

went into effect in 2006).

Annual Fuel Utilization Efficiency (AFUE)

measures the amount of fuel converted to 

heat at the furnace outlet in proportion to 

the amount of fuel entering the furnace. This 

is commonly expressed as a percentage. A 

furnace with an AFUE of 90 could be said 

to be 90% efficient.

Energy Efficiency Rating (EER)

is a rating of a central air conditioner’s 

steady-state efficiency at 80°F indoors 

and 95°F outdoors, measured once the air 

conditioner is up and running.

DOE is mandated by Congress to 

continually review and update appliance 

efficiency standards. For a schedule of 

appliance standards updates, see 

www.standardsasap.org/federal.htm

CHAPTER 9 / BUILDING AMERICA BEST PRACTICES SERIES

9.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
[The 2009 IECC 403.6 mandates that heating and cooling equipment 

be sized in accordance with the 2009 IRC M1401.3, which cites ACCA 

Manuals S and J for equipment sizing and load calculations. The 

2012 IECC 403.6 references ACCA Manuals S and J directly.]

One estimate states that a Manual J calculation takes about 30 to 60 

minutes for an average home, using the software and measurements 

from construction drawings. Manual S calculations require an 

additional 15 to 30 minutes (SBIC 2003). A single calculation can 

work for multiple uses of the same plans.

Central Gas-Fired Furnaces

For central gas-fired heating systems, high-efficiency (≥90% AFUE) 

sealed combustion gas furnaces should be installed. Sealed combustion 

means that an appliance acquires all air for combustion through a 

dedicated sealed passage from the outside to a sealed combustion 

chamber, and all combustion products are vented to the outside 

through a separate, dedicated sealed vent. Sealed-combustion, 

condensing appliances eliminate the potential for back-drafting. Variable 

speed motors, also known as electrically commutated motors (ECMs), 

are more efficient than regular furnace blower motors because they 

can operate at variable speeds allowing the speed to adjust to the 

heating and cooling needs of the house. Instead of repeatedly blasting 

on and shutting off, the variable speed motor runs the blower for 

longer periods at lower speeds, providing quieter operation, and more 

even heat and cooling. They can be more effective at reducing humidity 

levels in a home than a central HVAC with a single-stage blower.

Electric Heating and Heat Pumps

Electric furnaces, electric baseboard heating, and electric resistance 

wall units are used in all climates but, from a fuel-cost perspective, 

they are an expensive method for heating. One recent study 

reported electric furnace heating costs of $2.56/100,000 Btus and 

electric resistance heating costs of $2.05/100,000 Btus, compared to 

$1.49/100,000 Btus for gas heat and $0.82 /100,000 Btus for ductless 

heat pumps (based on fuel costs of $0.07/kWh electric, and $1.10/

therm gas) (Pratt 2008).

Heat pumps are more efficient than electric resistance heating. 

A standard heat pump unit with a Heating Seasonal Performance 

Factor (HSPF) of 7.7 or more (the minimum HSPF required by law 

as of 2006), can reduce electricity consumption for heating by 30% 

or more relative to electric resistance heating systems. In colder areas, 

when temperatures fall below 30°F, standard air-source heat pumps 

typically use electric resistance or gas furnaces to provide backup 

How Air Source Heat 

Pumps Work

In cooling mode, an air-source heat pump 

evaporates a refrigerant in the indoor 

coil; as the liquid evaporates it pulls heat 

from the air in the house. After the gas is 

compressed, it passes into the outdoor 

coil and condenses, releasing heat to the 

outside air. The pressure changes caused 

by the compressor and the expansion 

valve allow the gas to condense at a high 

temperature outside and evaporate at a 

lower temperature indoors.

In heating mode, an air-source heat pump 

evaporates a refrigerant in the outdoor 

coil. As the liquid evaporates, it pulls 

heat from the outside air. After the gas is 

compressed, it passes into the indoor coil 

and condenses, releasing heat to the inside 

of the house. The pressure changes caused 

by the compressor and the expansion 

valve allow the gas to evaporate at a low 

temperature outside and condense at a 

higher temperature indoors. In cooling 

mode, the reverse happens.

9.3

CHAPTER 9. MECHANICAL, PLUMBING, AND ELECTRICAL SYSTEMS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 9.3
heat to the home. Heat pumps also provide cooling; per Federal 

requirements since 2006, heat pumps and air conditioners must 

have a Seasonal Energy Efficiency Ratio (SEER) of 13 or higher. 

ENERGY STAR Version 3.0 criteria for heating equipment are 

climate specific. See the table on the next page for requirements.

Ductless Heat Pumps

Unlike central air source heat pumps, which use ducts and a large 

blower to distribute the hot or cool air throughout the house, 

ductless heat pumps use no ducts and directly heat and cool the area 

where they are located. Ductless heat pumps are sometimes referred 

to as mini-split heat pumps because they consist of a single outside 

compressor/condenser unit connected to one or more wall- or 

ceiling-mounted indoor air handler units. The indoor air handlers 

have dimensions of approximately 12x9x31 inches and weigh as 

little as 25 pounds. The outdoor units are approximately 25x12x31 

and weigh about 88 pounds. The outdoor units are mounted on a 

concrete pad or on the outside wall of the house. Tubing connects 

the two units through a small hole in the wall. 

Ductless heat pumps have been used in Asia and Europe since the 1970s 

and in U.S. commercial buildings since the 1980s, but they are not 

yet well known in the U.S. residential market. They are 25% to 50% 

more efficient than electric baseboard or wall heaters (NEEA 2009). 

Ductless heat pumps provide increased energy savings over standard 

heat pumps in several ways—because they are ductless and 

mounted inside conditioned space, there are no losses to the attic or 

crawlspace or through leaky ducts; they provide zoned heating and 

cooling; and advances in technology in recent years have increased 

performance to the point that HSPF 12/SEER 26 units are now 

available. These high-performing heat pumps also perform at a much 

wider temperature range than standard heat pumps: some models 

can operate at an outdoor temperature range of 5°F to 75°F for 

heating and 14°F to 115°F for cooling, eliminating or significantly 

reducing the need for backup heat sources in many locations. 

These ductless heat pumps use an inverter technology with a 

variable-speed compressor that can vary the refrigerant flow. They 

also have linear expansion valves rather than open-close valves and 

multi-speed rather than single-speed fans to continuously match 

the heating/cooling load. Unlike conventional air conditioning/

heating systems that stop and start repetitively, the inverter 

technology adjusts the motor speed, allowing the system to adapt 

more smoothly to shifts in demand with less temperature variation 

(top) Ductless heat pumps mount to the 

wall to provide zoned heating and cooling 

with exceptional energy performance.

(bottom) The outside unit of a ductless 

heat pump can be mounted on the wall 

or on a concrete pad on the ground.

CHAPTER 9 / BUILDING AMERICA BEST PRACTICES SERIES

9.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
and much lower energy use. When maximum capacity isn’t needed, 

compressor revolution and power decreases, increasing energy 

efficiency. For example, one model reports a capacity range of 3,100-

24,000 Btus in heating mode and 3,800-14,500 Btus in cooling mode.

For more information on ductless heat pumps, including installation 

tips, production selection recommendations, and performance 

details, see the website for the Northwest Ductless Heat Pump 

Project (www.nwductless.com), conducted by Bonneville Power 

Administration and Northwest Energy Efficiency Alliance (NEEA) 

(Bonneville Power Administration 2010; NEEA 2009). Begun in 

2008, the project included 12,047 ductless heat pumps installed in 

Northwest homes, 91 participating utilities, and 833 participating 

contractors by September 2011. Research results on energy savings 

will be out in 2012.

Ground-Source Heat Pumps

Geothermal or ground-source heat pumps can be very efficient for 

heating and cooling in this climate because they use the constant 

temperature of the earth as the exchange medium instead of the 

outside air temperature. This allows the system to reach fairly high 

efficiencies (200% -300%) on the coldest winter days, compared to 

100%-175% for central air-source heat pumps on cool days. The 

disadvantages are their initial installation cost and the need for yard 

space to install the piping. For more information on various HVAC 

technologies, see www.energysavers.gov.

Cooling Equipment

Mechanical cooling options in the mixed-humid climate include 

central air conditioning and air source heat pumps. 

Central air conditioners are typically installed with central furnaces 

and use the same ducts and blower. Refrigerant is piped to the 

evaporator coil in the air handler unit where it cools the distribution 

air. Air conditioners have become much more efficient over the past 

few decades. Technology improvements include variable-speed motors 

that allow more control over air distribution, which can lower energy 

consumption and increase comfort. The majority of systems rated 

SEER 15 or higher incorporate variable-speed motors to achieve this 

efficiency. Advanced compressors and micro-channel heat exchangers 

are other advancements that have improved efficiency.

Central air conditioning systems are rated according to their seasonal 

energy efficiency ratio (SEER). Since 2006 the federal government 

has required new air conditioners sold in the United States to have a 

(top) The newest models of air conditioners 

have efficiencies as high as SEER 20. Follow 

the manufacturer’s recommendations for 

charging to ensure that high efficiencies 

are achieved.

(bottom) Green Coast Enterprises is working 

with Building Science Corporation to study 

the cost-effectiveness of dehumidifiers that 

are ducted to the air handler in affordable 

homes in New Orleans. (Photo Source: 

Building Science Corporation)

ENERGY STAR Version 3.0 

HVAC Requirements

(2009 IECC Climate Zones 3 and 4)

Heating Equipment IECC CZ 1-3 IECC CZ 4-8

Gas Furnace ≥ 80 AFUE ≥ 90 AFUE

Oil Furnace ≥ 80 AFUE ≥ 85 AFUE

Boiler ≥ 80 AFUE ≥ 85 AFUE

Air Source Heat 

Pump with Electric 

Back-Up

≥ 8.2 HSPF/

14.5 SEER/

12 EER 

≥ 8.5 HSPF/

14.5 SEER/

12 EER (for 

CZ 4) 

Air Source Heat 

Pump with DualFuel Backup

CZ 1-8: ≥ 8.2 HSPF/

14.5 SEER/12 EER

Ground Source 

Heat Pump

Any ENERGY STAR–

qualified model

Cooling Equipment IECC CZ 1-3 IECC CZ 4-8

Air Conditioner ≥ 14 SEER/

12 EER 

≥ 13 SEER

Heat Pump See above

9.5

CHAPTER 9. MECHANICAL, PLUMBING, AND ELECTRICAL SYSTEMS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 9.5
SEER rating of 13 or higher. Split-system air conditioners (the type 

most common in homes) can use the ENERGY STAR label if they 

have a SEER of 14.5 or greater in IECC climate zones 1-3 or SEER 

13 or greater in IECC climate zones 4 through 8. The best available air 

conditioning units can have SEER ratings of over 20.

Correct installation and commissioning can have a big impact on air 

conditioner performance in the mixed-humid climate. The time-delay 

relay on many newer air conditioning units is set to keep the fan 

running for about two minutes after the compressor shuts off. The 

relay can help boost efficiency in dry climates, but allows some of 

the moisture on the evaporator coil to evaporate back into the air 

stream, contributing to increased indoor humidity in humid climates. 

The time-delay relay is typically jumper selectable and should be 

set to 30 seconds or less in humid climates. Also, the fan on central 

air conditioning systems should always be set to “Auto” rather than 

“On” for most efficient humidity control. Some air conditioners 

allow the compressor to start about 30 seconds before the blower 

starts and this is also recommended in humid climates to reduce 

“hot” blow and provide better dehumidification. Make sure the drain 

pans are correctly installed and drain all the condensate water rather 

than creating a puddle. Verify that the refrigerant level is correct at 

installation. The EPA reports that 75% of installed air conditioners 

had the wrong amount of refrigerant when tested. Incorrect 

refrigerant levels can lower efficiency by 5% to 20% and can cause 

premature component failure, resulting in costly repairs (see EPA 

Heating and Cooling Refrigerant Charging guidelines www.epa.gov).

Heat pumps are more efficient than standard electric air conditioning. 

Central air source heat pumps use ducts. Ductless heat pumps can 

provide zoned cooling. The highest performing models of ductless 

heat pumps offer SEER ratings as high as 26 at outside temperatures 

as high as 115°F. In very hot climates, their efficiency may need to be 

balanced against cost-effectiveness in comparison to other cooling 

technologies such as ductless heat pumps. 

Evaporative cooling is not recommended in the mixed-humid 

climate because it depends on low humidity to perform. Radiant 

cooling is not recommended in humid climates due to condensation 

issues on flooring. Ground source heat pumps can provide heating 

and cooling at high efficiencies in the mixed-humid climates, 

although their efficiency may need to be balanced against costeffectiveness in comparison to other cooling technologies such as 

ductless heat pumps.

Beach house builders have been using 

passive cooling techniques for decades, 

including deep overhangs, covered 

porches, awnings, openable windows that 

face prevailing breezes, and upper story 

windows that allow convective currents 

to draw air in through the first-floor 

porches and pull hot air out of secondand third-floor windows. Another beach 

house technique is to install shower stalls 

outside the house, either on the ground 

level or under the house if the first floor is 

raised up on stilts, to keep sand, heat, and 

humidity out of the house. 

CHAPTER 9 / BUILDING AMERICA BEST PRACTICES SERIES

9.6 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Pine Mountain Builders incorporated 

covered porches, deep overhangs, 

numerous windows, shade trees, and 

ceiling fans into its designs as passive 

cooling strategies in its Georgia homes. 

The builder also incorporated 14 SEER/8 

HSPF 8.0 air source heat pumps and, in 

some units, ground-source heat pumps, 

to provide heating and cooling. (Photo 

Source: Pine Mountain Builders)

Dehumidifiers

In the mixed-humid climate, there are times of the year, especially 

in the spring and fall, when the temperature is not high enough to 

call for air conditioning, but the humidity level is high enough to 

make conditions inside the home uncomfortable. At times like these, 

a dehumidifier can bring the humidity down to a comfortable level, 

without the need for air conditioning. 

One study done by Building America partner Building Science 

Corporation in Houston, Texas (Rudd et al. 2005) indicated that 

separate dehumidification is even more necessary in energy-efficient 

homes because efficiency measures like better insulation, air sealing, and 

energy-efficient windows reduce the home’s temperature but don’t reduce 

humidity. Also, in an energy-efficient home, a central air conditioning 

system does not have to operate as much to bring the indoor temperature 

down. Therefore, the air conditioner may not operate long enough to 

reduce the humidity, especially in the spring and fall when outdoor 

temperatures are not much higher than indoor temperatures. 

The Building Science Corporation study compared six different 

dehumidification and ventilation systems in 20 homes and found 

that supplemental dehumidification, in addition to that provided by 

the central cooling system, was required to maintain indoor relative 

humidity below 60% throughout the year. All of the energy-efficient 

homes that had additional dehumidifiers kept their homes below 

60% relative humidity at least 90% of the time. All of the homes that 

only had dehumidification as part of their air conditioning system 

experienced relative humidity higher than 60% for about 20% or more 

of the monitored hours. The study also compared six dehumidifier 

technologies, including expensive, integrated systems, and found that 

the dehumidifier system providing the best overall value, including 

humidity control, first cost, and operating cost, used a standard 

dehumidifier located in a hall closet with a louvered door and centralfan-integrated supply ventilation with fan cycling (Rudd et al. 2006).

Natural Cooling Strategies

Design strategies, fans, and shading are among the natural cooling 

strategies builders can employ. While these options don’t reduce 

humidity, they can help occupants to feel cooler and thus they may 

reduce air conditioning bills. 

Design strategies include siting on the lot to take advantage of natural 

breezes. In coastal environments, openable windows can be located 

on the side of the home that receives prevailing breezes and on the 

opposite side of the home to encourage cross ventilation. Porches 

9.7

CHAPTER 9. MECHANICAL, PLUMBING, AND ELECTRICAL SYSTEMS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 9.7
and two-story designs with open interiors can take advantage of the 

stack effect to draw air through the home during the shoulder seasons. 

Shading options include planting trees, designing in overhangs, 

especially over south-facing glass, and adding awnings, pergolas, and 

covered porches (see Chapter 5). Studies show ceiling fans can allow 

occupants to raise the thermostat 4°F in an air-conditioned room 

with no noticeable reduction in comfort. 

If the attic is unsealed, properly sized and placed roof vents (including 

soffit, ridge, and gable end vents) can help reduce heat in the attic. 

Motorized attic fans are not necessarily recommended because, if the 

ceiling is not air-tight, air conditioned air can be pulled out of the 

home and into the attic. Whole house fans are also not recommended 

in humid climates; because they require windows to be open for 

proper operation, they pull in significant amounts of humid outside 

air, and they push conditioned air into the attic. 

Low-emissivity, high-performance windows, which are described 

in the following sections, can help reduce solar heat gain. Radiant 

barriers (described in Chapter 7) and cool roofs (described in 

Chapter 5) are other passive strategies for minimizing heat gain in 

cooling-dominated parts of the mixed-humid climate.

For More Information on Heating and Cooling Equipment 

ACCA. 2010. ANSI/ACCA Standard #4 Maintenance of Residential HVAC Systems, 

Air Conditioning Contractors of America, Arlington, Virginia, www.acca.org 

ACCA. 2010. ANSI/ACCA Standard #5 HVAC Quality installation Specification, 

Air Conditioning Contractors of America, Arlington, Virginia, www.acca.org

ACCA. 2010. ANSI/ACCA Standard #6 Restoring the Cleanliness of HVAC Systems, 

Air Conditioning Contractors of America, Arlington, Virginia, www.acca.org

ACCA. 2010. ANSI/ACCA Standard #9 Quality Installation Verification. Air Conditioning 

Contractors of America, Arlington, Virginia, www.acca.org

Air Conditioning Contractors of America. 2007. ACCA Standard 5; HVAC Quality Installation 

Specification, ANSI/ACCA 5 QI-2007, Air Conditioning Contractors of America, 2800 

Shirlington Road, Suite 300, Arlington, VA. www.acca.org

Air Conditioning Contractors of America. Manual J: Residential Load Calculation, Eighth 

Edition. ACCA, Arlington, VA. www.acca.org

Air Conditioning Contractors of America. Manual S: Residential Equipment Selection. ACCA, 

Arlington, VA. www.acca.org

ASHRAE. 2007. Standard 52.2-2007, Method of Testing General Ventilation Air-Cleaning 

Devices for Removal Efficiency by Particle Size, available for purchase from ASHRAE’s 

bookstore www.ashrae.org 

Baylon, David, Kevin Geraghty, and Kacie Bedney. 2010. “Performance of Ductless Heat 

Pumps in the Pacific Northwest,” in Proceedings of the 2010 ACEEE Summer Study on Energy 

Efficiency in Buildings, prepared by Ecotope Inc. and Bonneville Power Administration.

CHAPTER 9 / BUILDING AMERICA BEST PRACTICES SERIES

9.8 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Bonneville Power Administration. 2010. Residential Ductless Mini-Split Heat Pump Retrofit 

Monitoring: 2008-2010 Analysis, prepared for BPA by Ecotope, www.bpa.gov/energy/N/DHP.cfm

Building Industry Institute. Procedures for HVAC System Installation.

www.thebii.org/hvac.pdf

Consortium for Advanced Residential Buildings. Designing Forced-Air HVAC Systems.

Steven Winter Associates, Inc. (CARB-SWA). www.carb-swa.com/Resources

Consortium for Energy Efficiency (CEE) and the Air-Conditioning, Heating, and 

Refrigeration Institute (AHRI). “Database of Qualifying ENERGY STAR Heat Pumps and Air 

Conditioners,” www.ceehvacdirectory.org

Consortium for Energy Efficiency. Residential HVAC: CEE-AHRI HVAC Directory.

www.cee1.org/resid/rs-ac/rs-ac-main.php3

Cowan, Laura. 2009. “How Heat Pumps Work.” May 13, 2009. 

http://home.howstuffworks.com/home-improvement/heating-and-cooling/heat-pump.htm

DOE. “Energy Savers – Heating Systems,” U.S. Department of Energy. www.energysavers.gov

DOE. “How to Size HVAC Systems Correctly,” U.S. Department of Energy Building Energy 

Codes Resource Center, http://resourcecenter.pnl.gov/cocoon/morf/ResourceCenter/article/137

DOE. “Right-Size Heating and Cooling Equipment,” U.S. Department of Energy Technology 

Fact Sheet, www.toolbase.org/Design-Construction-Guides/HVAC/right-size-hvac-equipment 

DOE. 2008. 2008 Buildings Energy Databook. U.S. Department of Energy, 

http://buildingsdatabook.eren.doe.gov/ 

DOE. 2011. HVAC: A Guide for Contractors to Share with Homeowners, Volume 14, Building 

America Best Practices Series, Prepared for the U.S. Department of Energy by Pacific 

Northwest National Laboratory, PNNL-20421, www.buildingamerica.gov. 

EPA. “Heating and Cooling: Sizing and Installation – Proper Refrigerant Charging,” U.S. 

Environmental Protection Agency. www.energystar.gov/index.cfm?c=heat_cool.pr_properly_sized

Furnace Filter Care. “Understanding MERV Ratings,” www.furnacefiltercare.com/merv-ratings.php

NEEA. 2009. Northwest Ductless Heat Pump Project: Project Overview and Installation 

Best Practices, Northwest Energy Efficiency Alliance, www.nwductless.com/contractors/

project-resources

Pratt, J.R. 2008. Ductless Heat Pumps, Presentation by Jeffrey R. Pratt Inc. for Bonneville 

Power Administration, www.bpa.gov/energy/n/Utilities_Sharing_EE/Energy_Smart_

Awareness/pdf/BPA_DHP_Presentation_022708.pdf

Rudd, Armin, Joseph Lstiburek, and Kohta Ueno. 2005. Residential Dehumidification 

Systems Research for Hot-Humid Climates, Building Science Corporation Research Report 

0505, www.nrel.gov/docs/fy05osti/36643.pdf

Sustainable Buildings Industry Council (SBIC). 2003. Green Building Guidelines: Meeting 

the Demand for Low-Energy, Resource-Efficient Homes. U.S. DOE. Washington, D.C. 

9.9

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Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 9.9
Ducts and Air Handlers

Duct System Design and Layout

With central forced-air systems, the gas or electric furnace and ducts are 

often located in unconditioned space in the attic, garage, or crawlspace. 

As typically installed, this “default” design is assumed in codes to reduce 

system efficiency by about 20%, while placing ducts in conditioned 

space is assumed to cut air loss to about 4% (ICC 2006 as reported 

in Lubliner et al. 2008). Numerous studies have shown significant 

savings from moving the ducts and air handler into conditioned space. 

In a modeling study conducted in Spokane, Washington, by Building 

America research partner Washington State Energy Office, using a 

home built to the current Washington State Energy code, moving ducts 

out of a vented crawlspace and into the home resulted in heating energy 

savings of 28.4% and cooling savings of 17% (Hales et al. 2010). 

As data confirm, the best practice is to locate the ducts in conditioned 

space so that any leakage that does occur will send air to or draw air 

from conditioned space. Ducts may be run through open-web floor 

trusses in a two-story home, through a dropped hallway ceiling in a 

one-story home, or through a conditioned attic. Ducts should not be 

located in exterior walls. Air handlers should be located in conditioned 

space, such as a closet inside the home, in a conditioned attic or 

basement, or in an air-sealed and conditioned closet in the garage. 

In all cases, duct systems should be designed using ACCA Manual D

[2009 and 2012 IRC M1601.1]; duct runs should be as short as possible, and 

duct sizes and layouts should be shown on plans. Building cavities should 

not be used as supply ducts or return ducts [2009 and 2012 IECC 403.2.3].

Keeping ducts and air handlers inside conditioned space typically 

impacts architectural design and should be considered early in the 

design process. Duct chases or dropped soffits may require thinking 

through the sequence of how trade contractors will do the installation. 

All four of the Building America builders described in the case 

studies in this guide locate their ducts in conditioned space. Two put 

the ducts in open-web floor joists between floors. One puts ducts in 

sealed, insulated crawlspaces, and one puts ducts in insulated attics. 

Another Building America builder, Quadrant Homes, in Seattle, 

Washington, moved the furnaces out of the attic into conditioned 

space in a second-floor utility closet, and located the ducts in 

open-web floor trusses between the first and second floor. Quadrant’s 

HVAC contractor, Wade Craig of Bob’s Heating, noted several 

advantages to the move. When ducts are installed between floors, 

Duct Run Configurations

Here are three example designs for putting 

the HVAC and ducts in conditioned space.

(Source: Building Science Corporation)

Transfer grilles 

serve as a return 

air pathway to 

the air handling 

unit when the 

bedroom doors 

are closed.

Transfer 

grilles serve 

as a return air 

pathway to the 

air handling 

unit when the 

bedroom doors 

are closed.

Transfer 

grilles serve 

as a return air 

pathway to the 

air handling 

unit when the 

bedroom doors 

are closed.

CHAPTER 9 / BUILDING AMERICA BEST PRACTICES SERIES

9.10 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
they are clearly visible to the general contractor and inspector, 

encouraging better installations. They are less likely to suffer from 

“trade damage” from electrical or plumbing subcontractors who step 

on or squish the ducts when installing wires or pipes. Putting the air 

handler in a closet on the second floor makes equipment servicing 

easier and improves worker safety during installation and retrofits. 

Craig said his firm can lower its bid when the HVAC system is 

moved inside. “It is a lot easier for installers to do a quality job when 

they are not lying in the mud, deep in a corner of the crawlspace,” 

said Craig. Quadrant is aware of the potential for air leakage 

pathways between floors at rim joists so all ducts are sealed with 

mastic and tested with a Duct BlasterTM (Lubliner et al. 2008).

If ducts are not in conditioned space, one alternative is to locate the 

ducts on the ceiling deck of an unconditioned attic and “bury” the 

ducts with blown-in insulation. In humid climates this strategy is not 

recommended because condensation could occur at the duct exterior 

surface. Building America researchers have investigated burying ducts 

in attic insulation above ceilings and based on this research, buried 

ducts may be permissible but the ducts should be directly insulated 

to R-8, apart from the piled-on insulation. Building America does 

not recommend using the buried duct approach in climates where 

the summertime attic dew point temperature is often above 60°F, or 

if the Jul-Aug monthly average outdoor dew point temperature is 

above 60°F (refer to Table 6-3 of ASHRAE Standard 90.2-1993). The 

mixed-humid and hot-humid climates often exceed this dew point 

and so buried ducts are specifically not recommended there. In other 

climates, such as cold climates up through the humid river valleys, 

builders and designers should be cautious.

Locating air handlers and return ducts in the garage is not 

recommended because of the potential for drawing carbon monoxide 

and hazardous fumes into the home. If the air handler must be located 

in the garage, it should be enclosed in an insulated, air-sealed closet. 

Ducts located in the garage may not have any openings in the garage 

[2009 IRC R302.5.2] and furnaces and air handlers that supply air to 

living spaces shall not supply air to or return air from a garage [2009 

IRC M1601.6]. The air handler and any return-air ductwork should be 

thoroughly sealed with UL 181B-M-compliant mastic, with a target 

leakage between the duct system and the garage of 0 CFM @25 Pa. 

Duct Sealing and Insulating

Leaky duct systems cause energy losses, but they can also depressurize 

the house, which can pull outdoor, unfiltered air into the house from 

attics, crawlspaces, attached garages, and through building walls. 

(Top and Bottom) These Building America 

builders run ducts through openweb floor trusses to keep the ducts in 

conditioned space. Open-web trusses 

allow subcontractors the flexibility to run 

plumbing, electrical, and ductwork easily 

between floors, with little to no “trade 

damage” or “trade fighting.” Air handlers 

are located in conditioned space in the 

home or in an air-sealed closet in the garage.

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Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 9.11
All ducts, air handlers, and filter boxes should be airsealed and joints 

and seams should comply with the 2009 IRC M1601.4.1. The 2009 IRC 

describes several UL 181-approved sealing methods. Building America 

recommends water-based mastic that complies with UL 181B-M, as 

appropriate. Duct-drywall connections should be sealed with caulk 

or foam sealant or mastic. Leaky ductwork in an unconditioned attic 

or crawlspace not only leaks energy but it can also draw unhealthy air 

into the air distribution system. Sealing ducts with mastic is desirable 

even for ducts located in conditioned spaces. Properly sealed ducts 

make sure air gets to the rooms intended, rather than leaking into 

a plenum space. It also minimizes the chances of creating pressure 

differentials from room to room that can cause drafts. The doublecheck inherent in the process of sealing each joint reduces the chances 

of unconnected ductwork, which is a surprisingly common mistake. 

Although mastic is the most reliable duct sealing method, the 

2009 IRC M1601.4.1 allows certain approved tapes and DOE research 

has found that some tapes perform adequately for sealing ducts, 

particularly fiberglass board ducts (see sidebar). However, highperformance tapes may be difficult to identify and traditional duct 

tape (cloth-backed rubber adhesive tape) should never be used 

to seal ducts, even if it meets UL ratings. Tapes have low tensile 

strength and should not be used to mechanically support ducts. 

If the ducts are placed in unconditioned attic spaces, 10% to 30% 

of the energy used to cool the air can be lost to conduction through 

the duct surfaces due to the extreme summer temperatures in these 

spaces. Supply ducts in attics should be insulated to R-8 minimum 

and all other ducts should be insulated to R-6 minimum; insulation 

is not required for ducts located inside the building’s thermal 

envelope [per 2009 IECC 403.2 and 2012 IECC R403.2, and ENERGY 

STAR Version 3.0]. 

Duct air tightness should be verified with duct blaster pressure testing. 

[The 2009 IECC 403.2 requires that ducts be tested for air tightness 

and allows for the testing to occur either before drywall is put up 

or after drywall is put up. If tested at pre-drywall or rough-in, duct 

leakage must be ≤ 6 cfm per 100 ft2

 of conditioned floor area at 25 

Pa; if tested after construction, then it must be ≤ 8 cfm at 25 Pa. The 

2012 IECC R403.2 requires that duct joints be connected and sealed 

according to the International Mechanical and Residential Codes and 

that duct leakage be tested with total leakage ≤ 4 cfm per 100 ft2

 of 

conditioned floor area at 25 Pascals across the entire system including 

the air handler when tested at rough-in or post-construction. (If the 

airhandler and all ducts are in conditioned space, duct leakage testing 

is not required.)] Building America recommends testing at rough-in 

when leaks can be easily accessed and sealed.

(1) One technique for placing ducts in 

conditioned space is to run a duct chase in a 

dropped ceiling down the main hallway of the 

house with registers off the sides for each room. 

This technique allows for compact duct design.

(2) This finished house shows registers 

going directly from a main duct chase in 

the dropped hallway ceiling.

(3) This air handler closet is located in the 

garage space but is isolated with thermal 

and air barriers.

CHAPTER 9 / BUILDING AMERICA BEST PRACTICES SERIES

9.12 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
For More Information on Duct Layout and Sealing

2009 IECC. 2009. International Energy Conservation Code, Section 403.2.2 “Sealing,” 

and “Table 4.4.5.2(.2) – Default distribution system efficiencies for the proposed design.” 

International Code Council (ICC), Washington, D.C. www.iccsafe.org/Store/Pages

2009 IRC. 2009. International Residential Code - One and Two-Family Dwellings, 

International Code Council (ICC), Washington, D.C. www.iccsafe.org/Store/Pages

Air Conditioning Contractors of America (ACCA). Manual D: Residential Duct Systems. 

ACCA, Arlington, VA. www.acca.org

Air Conditioning Contractors of America. Manual T: Air Distribution Basics for Residential 

and Small Commercial Buildings. ACCA, Arlington, VA. www.acca.org

California Energy Commission. 2003. Home Builders Guide to Ducts in Conditioned Space.

P500-03-82-A16. www.sabreargentina.com/downloads/FinalAttachments/A-16_Bldrs_

Guide_Ducts_6.3.4.pdf

California Energy Commission. 2005. 2005 Building Energy Efficiency Standards: 

Residential Compliance Manual. CEC-400-2005-005-CMF. Sacramento, CA. 

www.energy.ca.gov/title24/2005standards/residential_manual.html#4Q

D. Griffiths, M. Zuluaga, D. Springer, and R. Aldrich. 2004. “Insulation Buried Attic Ducts – 

Analysis and Field Evaluation Findings.” American Council for an Energy-Efficient Economy 

(ACEEE). 2004 ACEEE Summer Study on Energy Efficiency in Buildings. Pacific Grove, CA. 

August 23, 2004.

DOE. 2004. Better Duct Systems for Home Heating and Cooling, NREL/BR-550-30506; DOE/

GO-102004-1606. U.S. DOE Building America Program, www.buildingamerica.gov

FSEC. Designing and Building Interior Duct Systems, FSEC-PF-365-01. Florida Solar Energy 

Center, http://securedb.fsec.ucf.edu/pub/pub_show_detail?v_pub_id=4013

Fonorow, Ken, Dave Jenkins, Stephanie Thomas-Rees, and Subrato Chandra. 2010. 

“Low-Cost Interior Duct Systems for High-Performance Homes in Hot Climates.” in the 

Proceedings of the ACEEE Summer Study on Energy Efficiency in Buildings,

www.aceee.org/proceedings

Hales, David and David Baylon. 2010. “Moving ducts into conditioned space: getting to code 

in the Pacific Northwest,” ASHRAE Transactions, report # 3616

Hedrick, R. 2003. Home Builders Guide to Ducts in the Conditioned Space, California Energy 

Commission, 200-03-082-A16, www.energy.ca.gov/pier/project_reports/500-03-082.html

HGTVPro.com. “How to Seal Ductwork,” www.hgtvpro.com/hpro/bp_mechanical/article/0,,

HPRO_20151_4583390,00.html

Lubliner, Michael, Ryan Kerr, Andy Gordon, and Chuck Murray. 2008. “Moving Ducts Inside: 

Big Builders, Scientists Find Common Ground,” In Proceeding of the 2008 ACEEE Summer 

Study on Energy Efficiency in Buildings, www.energy.wsu.edu/documents/code/ACEEE_

Ducts_Inside.pdf

McIlvaine, j.R., D. Beal, and P. W. Fairey III. 2002. Design and Construction of Interior 

Duct Systems. Florida Solar Energy Center, Cocoa, Florida, FSEC-PF-365-01, 

www.baihp.org/pubs/pdf/interior_ducts.pdf. 

Regional Technical Forum (RTF). 2006. Deemed Savings for New Construction Homes.

Portland, OR.

Sherman, M, and I. Walker. 1998. “Can Duct Tape Take the Heat?” Home Energy Magazine, 

Berkeley, California. http://homeenergy.org/archive/hem.dis.anl.gov/eehem/98/980710.html

Mastic provides the most reliable duct 

sealing method. Ducts should be located in 

conditioned space. (Photo source: BAIHP)

Standards for Duct Sealants

Underwriters Laboratories, Inc. (UL) 

publishes several standards that relate 

to duct sealants, the most important of 

which is UL 181. It deals with ducts in 

general; UL 181A covers field-assembled 

duct-board and UL 181B covers flex duct 

systems. Each standard includes test 

procedures for sealants. Duct tapes and 

packing tapes that pass UL 181B are labeled 

“UL 181B-FX.” Mastics can pass 181A or B 

and are labeled “UL 181A-M” or “UL 181BM.” Foil tapes are designated with a P. 

Most tapes that are labeled 181B-FX are 

duct tapes. UL 181A and 181B appear to 

do a good job of testing for safety, tensile 

strength, and initial adhesion. However, 

they may not do a good job of rating how 

well sealants seal typical duct leaks or 

how well they stay sealed under 

normal conditions.

California Title 24 residential building 

standards require that duct sealants meet 

UL 181, UL 181A, UL 181B, or UL 723 (for 

aerosol sealants). The California Energy 

Commission has approved a cloth-backed 

duct tape with a special butyl adhesive 

(CEC 2005). Metal ducts are to be sealed 

with UL 181 mastic. For duct board, UL 

181 tapes are accepted. For flex duct, a 

combination of UL 181 mastic and strap 

ties should be used.

Adapted from Sherman and Walker 1998.

9.13

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Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 9.13
Pressure Balancing

Pressure imbalances from indoors to outdoors or room to room 

can draw moisture-laden air into wall cavities. Imbalanced airflows 

can also cause drafts and temperature differences between rooms or 

floors, leading to comfort complaints. 

One key factor in eliminating pressure imbalances is providing an 

adequate return air path to the air handler. Four methods for providing 

a return air path are as follows: 1) ducted returns from each room 

to the air handler; 2) room-to-room ceiling jump ducts; 3) transfer 

grilles or transoms; and 4) door undercuts. Door undercuts are 

often too small and/or are blocked by the installation of carpeting. 

Consequently, they should not be relied on to provide adequate return 

air pathways and should be supplemented by other methods.

Sound transmission in jump ducts or transfer grilles can be minimized 

by the use of flex duct, duct lining with sound-absorbent material, a 

slightly circuitous path, or some combination of these strategies.

Examples of Jump Ducts and Transfer Grilles for Pressure Balancing

(Figure source: Building 

Science Corporation)

For More Information on 

Pressure Balancing in Homes

Associated Air Balance Council. AABC National 

Standards for Total System Balance. 2002. 

www.aabchq.com/resources/national.aspx

National Environmental Balancing Bureau 

(NEBB). Section 15990 - Testing, Adjusting, 

and Balancing. www.nebb.org/tabspec.htm

CHAPTER 9 / BUILDING AMERICA BEST PRACTICES SERIES

9.14 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Air Distribution Fans

Fan motors on HVAC equipment can have a large impact on 

year-round energy use because they are often shared by heating, 

cooling, and ventilation systems. Nearly all furnace manufacturers 

offer “variable-speed” brushless permanent magnet (BPM) direct 

current motors. These motors have higher efficiency and, unlike 

permanent split-capacitor motors, BPM motors retain their high 

efficiency at reduced fan speeds. Although BPM motors may have a 

price premium of $200 or more, they are a recommended means of 

lowering HVAC energy use, and are required for two-stage heating 

and cooling systems. Some types also maintain a constant air flow as 

filters become dirty or registers are closed.

Ventilation

Building America recommends that all new homes be equipped with 

whole-house mechanical ventilation. Mechanical ventilation systems 

for indoor air quality include exhaust-only fans, supply-only systems, 

and balanced systems. 

Supply-Only Ventilation Systems 

A supply-only ventilation system brings outside air to the intake 

side of a home’s central air handler. A central fan-integrated supply 

ventilation system uses an exterior air intake that is ducted to the 

return air side of the HVAC system. An advantage of supply-only 

ventilation is that it can positively pressurize the house, which is 

desirable in humid climates as it reduces intrusion of moisture-laden 

outside air as well as radon. Also the fresh air volume can be 

adjusted to meet ASHRAE 62.2 requirements, outside air is filtered, 

and fresh air is delivered to every space (Russell, Sherman, and Rudd 

2006). Code requires that outdoor air intakes and exhausts should 

be equipped with automatic or gravity dampers that close when the 

ventilation system is not in operation [2009 IECC 403.5]. 

Building America team member Building Science Corporation 

recommends that electronic controls be added, including a motorized 

damper and timer to open the damper in sync with operation of the 

HVAC fan for automatic ventilation of the home at regular intervals 

throughout the day. This approach would run the central fan on a 

timer basis, even when the compressor is not running. 

Another approach to supply air ventilation is to have a run-time only 

ventilation system that introduces filtered outdoor ventilation air 

only when the compressor runs, i.e., only when heating and cooling 

happens. This approach has been used by several Building America 

builders (Chandra et al. 2009). The motorized outside air damper 

(top) Transfer grilles help balance air 

pressure between rooms, which helps to 

minimize drafts and comfort complaints.

(bottom) Installing jump ducts from room 

to room is one way to balance pressures. 

(Photo source: IBACOS)

ASHRAE 62.2

In 2003, the American Society of Heating, 

Refrigerating and Air-Conditioning 

Engineers (ASHRAE) established a new 

standard for indoor ventilation in residences. 

The standard is ASHRAE 62.2, Ventilation for 

Acceptable Indoor Air Quality in Low-Rise 

Residential Buildings (ASHRAE 2003). The 

Standard is on a three-year publishing cycle 

and has been republished in 2004, 2007, 

and 2010 with minor updates. 

ASHRAE Standard 62.2 requires a 

continuous ventilation rate of 1 cfm 

per 100 ft2 of building area plus 

7.5 cfm x (# bedrooms +1). An intermittent 

fan can meet this requirement if the 

airflow rate is adjusted upward based 

on specific ventilation effectiveness 

requirements published in the standard. In 

hot-humid climates, ASHRAE 62.2 requires 

supplemental dehumidification systems to 

control humidity. Builders who do not use 

supplemental dehumidifiers sometimes 

choose to provide whole house ventilation 

rates that are significantly lower than 

required by 62.2 to avoid over-ventilating 

the house with unconditioned air.

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Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 9.15
and associated control can be used to limit outside air introduction to 

a set maximum, regardless of how long the fan operates. Continuous 

operation of the air handler fan is not recommended as it would 

consume too much electricity and is detrimental to humidity control in 

humid climates (Rudd 2011). 

Central fan-integrated supply ventilation can be used with a central 

air handler equipped with an electronically commutated motor 

(ECM) rather than a permanent split capacitor (PSC) motor and 

some fan energy consumption savings may be possible (Rudd 2011). 

The key is that the ducts have been properly designed and installed 

according to manufacturers’ specifications to eliminate excessive 

airflow resistance. However, there are still concerns that, at the high 

speed required to draw enough air in through the outside air intake, 

the ECM is likely to have no savings relative to a PSC blower and 

at the lower air flows where the ECM performs better, the air flow 

through the exterior duct will not meet desired ventilation rates.

For homes that don’t have a central heating and cooling system, an 

electric fan, like an exhaust fan, can be installed in or ducted to an 

exterior wall to draw in outside air. This outside air should be mixed 

with indoor air before it is delivered into the home (Rudd 2011).

Exhaust-Only Ventilation

Continuously operating an exhaust fan located in a bathroom or central 

area of the house provides low-cost ventilation that meets ASHRAE 

62.2. High-quality, quiet, efficient fans that have separate speeds for 

ventilation and exhaust are typically used for this application. A better 

solution than an isolated exhaust fan is to tie all bathroom exhaust 

ducts together and route them through a single, continuously operating, 

high-efficacy axial fan that is vented to the home’s exterior. 

Exhaust fans help to improve indoor air quality by removing air 

contaminants near their source, such as moisture from a shower. 

Because exhaust fans draw air from leaks in the building envelope, air 

is not filtered, will not be evenly distributed, and comes from unknown 

sources. Another concern with exhaust-only ventilation systems is 

that the exhaust fans (when combined with other exhaust systems 

in the home including kitchen range fans, clothes dryers, fireplaces, 

and central vacuums) may draw too much air out of a home, creating 

a negative pressure in the home. In an inefficient, leaky home, this 

negative pressure pulls outside air in through cracks around doors and 

windows and leaks in walls. In a high-performance home, those air 

leaks have been sealed up so a fresh air intake must be added to the 

home to supply fresh air. Failing to provide an outside air intake can 

cause the home to become negatively pressurized. This can increase 

Supply-only ventilation brings in fresh 

outside air through a dedicated duct 

(Figure Source: Rudd 2011).

Exhaust fans provide simple, inexpensive 

ventilation but may depressurize the 

house, pulling air in from crawlspaces 

and through cracks in the walls 

(Figure Source: Rudd 2011).

CHAPTER 9 / BUILDING AMERICA BEST PRACTICES SERIES

9.16 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
the risk of backdrafting any combustion (fuel-burning) appliances 

or fireplaces that may be in the home. Backdrafting occurs when the 

flue’s natural ability to draw combustion fumes out of the house is 

overpowered and, instead, these fumes (including carbon monoxide) 

are pulled into the house. Negative pressure in a house can also draw 

in hot outside air, soil gases, garage fumes, and pollens.

Balanced Systems

Balanced systems intentionally provide both supply and exhaust. 

The best means for providing this balanced ventilation is with a 

heat recovery ventilator (HRV) or an energy recovery ventilator 

(ERV). Both provide a controlled way of ventilating a home while 

minimizing energy loss because they incorporate a heat exchanger 

that uses the heat or cooling from the outgoing exhaust air to warm 

or cool the fresh incoming air. The incoming and outgoing air 

volumes are balanced and air is evenly distributed throughout the 

house. ERVs and HRVs can share a central furnace air handler and 

duct system or have their own duct system. The main difference 

between an HRV and an ERV is the way the heat exchanger works. 

With an ERV (also called an enthalpy-recovery ventilator), the 

heat exchanger transfers water vapor along with heat energy, while 

an HRV only transfers heat. See the manufacturers’ specifications 

for determining which model is best in which climate and install 

it according to their directions for best performance, especially in 

regard to ERVs in humid climates. Most ERVs can recover about 

70% to 80% of the sensible energy in the exiting air (Rudd 2011).

Balanced whole-house ventilation systems both exhaust and supply 

in roughly equal amounts. Inside air is exhausted to the outdoors and 

outside air is supplied indoors. Balanced ventilation, by definition, 

should not affect the pressure of the interior space relative to outdoors. 

HRVs and ERVs are balanced systems. A balanced system can also be 

made up of any combination of the exhaust and supply ventilation 

systems described above (Rudd 2011). In reality the balance may never 

be perfect due to fluctuations in wind and stack pressures. Balanced 

ventilation can be used effectively in any climate. Rudd 2011 shows 

several examples of configurations of balanced systems. 

For More Information on Ventilation Systems

2009 IECC. 2009. International Energy Conservation Code, Section 403.5, “Mechanical 

Ventilation,” Section 403.6, “Equipment Sizing,” International Code Council (ICC), 

Washington, DC. www.iccsafe.org/Store/Pages

2009 IRC. 2009. International Residential Code - One and Two-Family Dwellings, Section 

M1502.1 “Clothes Dryer Exhaust – General,” International Code Council (ICC), Washington, DC. 

www.iccsafe.org/Store/Pages

Air Conditioning Contractors of America. Manual T. Air Distribution Basics for Residential 

and Small Commercial Buildings. ACCA, Arlington, VA. www.acca.org

Heat and energy recovery ventilators (HRVs 

and ERVs) bring in fresh air, exhaust stale 

air, and save energy by transferring heat 

to incoming air through a heat exchanger 

(Figure Source: Rudd 2011).

Semi-balanced ventilation systems 

provide fresh air and exhaust stale air 

but flow rates may not be balanced 

(Figure Source: Rudd 2011).

9.17

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Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 9.17
ASHRAE Standard 62.2-2010 Ventilation and Acceptable Indoor Air Quality in 

Low-Rise Residential Buildings (ANSI/ASHRAE Approved) can be previewed at 

www.ashrae.org/technology/page/548

Building Energy Codes Resource Center “Whole-House Mechanical Ventilation – 

Code Notes,” U.S. Department of Energy, http://resourcecenter.pnl.gov/cocoon/morf/

ResourceCenter/article/1467

Chandra, S, D Parker, J Sherwin, C Colon, K Fonorow, D Stroer, E Martin, J McIlvaine, 

D Chasar, N Moyer, S Thomas-Rees, D Hoak, D Beal, and C Gil. 2009. An Overview of 

Building America Industrialized Housing Partnership (BAIHP) Activities in Hot-Humid 

Climates, FSEC-PF-439-09, Florida Solar Energy Center, 

www.fsec.ucf.edu/en/publications/pdf/FSEC-PF-439-09.pdf

ENERGY STAR Thermal Bypass Checklist Guide, 2008, available at www.energystar.gov/ia/

partners/bldrs_lenders_raters/downloads/TBC_Guide_062507.pdf, pg. 13

Hoeschele, Marc. 2008. Development of an Integrated Residential Heating, Ventilation, 

Cooling, and Dehumidification System for Residences, Prepared by Davis Energy Group 

for the U.S. Department of Energy, www.davisenergy.com/docs/FinalReport_SBIR2_IHVCD_061808.pdf

Holladay, Martin. 2010a. “Designing a Good Ventilation System: Ventilating Is Easy — 

It’s Ventilating Right That’s Hard,” Green Building Advisor.com posted June 15, 2010. 

www.greenbuildingadvisor.com/blogs/dept/musings/designing-good-ventilation-system

Holladay, Martin. 2010b. “HRV or ERV? Choosing the right equipment for a balanced 

ventilation system,” Green Building Advisor.com posted January 22, 2010. 

www.greenbuildingadvisor.com/blogs/dept/musings/hrv-or-erv

HVI. 2006. “Fresh Ideas in Residential Ventilation.” Home Ventilating Institute. Wauconda, IL. 

www.hvi.org/resourcelibrary/HomeVentGuideArticles.html

Lawrence Berkeley National Laboratory. Thermal Energy Distribution Website at 

http://ducts.lbl.gov

Minnesota Department of Commerce Energy Information Center. June 23, 2008. 

“Maintain home ventilation systems to provide healthy air supply.” Available at 

www.state.mn.us/portal/mn/jsp/common/content/include/contentitem.jsp?contentid=536886092

NAHB Research Center. “Whole-House Mechanical Ventilation Strategies,” 

www.toolbase.org/Technology-Inventory/HVAC/whole-house-mechanical-ventilation

Piazza, T., R.H. Lee, M. Sherman, and P. Price. 2007. Study of Ventilation Practices and 

Household Characteristics in New California Homes. CEC-500-2007-033. California Energy 

Commission, Sacramento, CA., www.energy.cq.gov/2007publications/CEC-500-2007-033/

CEC-500-2007-033.PDF

Rudd, Armin. 2006. Ventilation Guide. Building Science Press Inc., Energy & Environmental 

Building Association, Minneapolis, MN, available for purchase at 

www.eeba.org/bookstore/prod-Ventilation_Guide-10.aspx

Rudd, Armin. 2011. Local Exhaust and Whole House Ventilation Strategies, Prepared by 

Building Science Corporation for the U.S. Department of Energy.

Russell, Marion, Max Sherman and Armin Rudd. 2007. “Review of Residential Ventilation 

Technologies.” HVAC&R Research, Vol. 13, No. 2, p. 325-348, March 2007. ASHRAE. 

http://findarticles.com/p/articles/mi_m5PRD/is_2_13/ai_n25007553

U.S. Environmental Protection Agency. 2009. Indoor airPLUS Construction Specifications, 

www.epa.gov/indoorairplus/index.html

Nelson Construction attached a fresh air 

intake with a timed mechanical damper 

controller to regulate fresh air flow into 

the return plenum of the HVAC air handler. 

The damper can be set to open allowing 

fresh air to be pulled into the air handler 

by the air handler fan, also operated by the 

timer. This draws fresh air into the house 

at regular intervals. When combined with 

timed exhaust fans, this provides lowcost balanced ventilation. (Photo Source: 

Building Science Corporation)

CHAPTER 9 / BUILDING AMERICA BEST PRACTICES SERIES

9.18 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Plumbing and Water Heating

Residential hot water energy use accounts for approximately 19% of 

the residential energy consumed in the United States, according to 

the Energy Information Administration. In new, high-performance 

homes, hot water energy accounts for a higher percentage, typically 

21% to 32%. Hot water systems don’t use more energy than they 

used to but they take a relatively larger share of the energy use in 

homes because, in tighter houses, less energy is required to heat and 

cool the homes than in older homes built to less stringent standards. 

There are several measures builders can take to reduce the amount 

of energy needed for water heating: 

•	 Install high-efficiency electric or gas water heaters. Specify sealedcombustion, power-vented, or direct-vented gas water heaters. 

These models save energy and reduce the risk of backdrafting 

flue gases into the house.

•	 Consider alternative technologies like tankless gas heaters, solar 

thermal water heaters, and air-source heat-pump water heaters.

•	 Insulate hot water supply lines to R-4 and install tanks that have 

at least R-12. [2009 IECC and 2012 IECC 403.3 require R-3 minimum 

insulation on pipes.]

•	 Consolidate bathrooms and other hot water-consuming activities 

into the same area(s) of the house.

•	 Place the water heater in a central location inside the home to minimize 

piping trunk lengths. Use a central manifold distribution system.

•	 Locate plumbing pipes in the attic and cover with insulation in 

single-story, slab-on-grade homes. Locate the pipes in interstitial 

space between floors for multi-story homes.

•	 Do not install plumbing in exterior walls. 

•	 Do not oversize piping. Use code-permitted minimums. 

Bigger isn’t better.

•	 Do not use continuous recirculation pumps. If recirculating 

pumps are specified, the pumps should be controlled by timers 

or on-demand to stop continuous operation.

•	 Seal around plumbing penetrations in all exterior surfaces, 

surfaces that border on unconditioned spaces, and between 

floors. Use fire-resistant sealant in plates between floors.

In an NAHB Research Center study, the 

central manifold hot water distribution 

system provided hot water to the fixtures 

more quickly than traditional trunk 

and branch and remote manifold 

distribution methods.

Code/Above Code 

Water Pipe Insulation

A comparison of the 2009 and 2012 IECC 

and Building America Recommendations

Code Pipe Insulation for hot 

and cold water pipes

2009 IECC 403.3 R-3

2012 IECC 403.3 R-3

Above Code

ENERGY STAR 

Ver. 3.0 R-4

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Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 9.19
Hot Water Distribution

Essentially there are three types of hot water distribution systems: 

1) the traditional “trunk and branch” with a large main line 

feeding smaller pipes that then flow directly to fixtures or split to 

serve multiple fixtures; 2) the central manifold (homerun) where 

the water heater feeds a manifold with dedicated lines running to 

each household fixture; and 3) the remote manifold system, which 

includes trunk lines that run to remote manifolds that serve clusters 

of fixtures, such as in one or more bathrooms or a kitchen.

The NAHB Research Center tested the three water distribution 

systems—trunk and branch, central manifold, and remote manifold—

and found that, while all three supplied sufficient flow, the central 

manifold system provided the quickest hot water to the fixtures and 

the most stable pressure when multiple fixtures were used. 

Common plumbing pipe materials are copper and PEX (cross-linked 

polyethylene). PEX installation can save labor and materials and 

can be cost competitive with rigid pipe systems. The NAHBRC 

points out that because PEX piping will not corrode and resists 

scale buildup, maintenance costs may be lower than for rigid piping. 

Fewer leaks are possible because fewer connections are required.

PEX piping should not connect directly to a hot water tank or solar 

water heater where the temperature of the water could exceed 200°F. 

PEX piping should not be used in installations subject to continual 

ultraviolet light exposure.

Hot Water Circulation Pumps and Controls

Do not use continuous recirculation systems for hot water. These 

systems keep hot water continuously flowing through pipes and result 

in substantial heat loss. If solar thermal water heating systems are 

used, the flow-through solar collectors should always be kept separate 

from any hot water recirculation systems. 

If recirculation systems are used, install an automatic or readily 

accessible manual control to turn off the hot-water circulating pump 

when the system is not in use [per 2009 IECC and 2012 IECC 403.4] 

and insulate the pipe to R-2. An on-demand system recirculates the 

water through the hot water tank only when hot water is needed. 

This system helps eliminate wasted water down the drain and is best 

suited for fixtures located far from the water heater. On-demand 

recirculators do not save energy except in comparison to continuous 

recirculation systems. 

Hot Water Distribution Systems

HEATER MANIFOLD

BATH II

KITCHEN

UTILITY

ROOM

BATH I

UTILITY

ROOM

KITCHEN BATH II

Traditional Trunk System

More Efficient Manifold System

BATH I

HEATER

CHAPTER 9 / BUILDING AMERICA BEST PRACTICES SERIES

9.20 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Water Heaters

Performance rating information for conventional storage water 

heaters, electric heat pumps, and tankless water heaters is available 

from the Air-Conditioning, Heating, and Refrigeration Institute 

(AHRI) (www.ahrinet.org). AHRI’s members include appliance 

manufacturers that use all fuel types. Performance rating information 

for solar thermal collectors and systems is available from the Solar 

Rating and Certification Corporation (www.solar-rating.org). 

Five types of ENERGY STAR-qualified water heaters are now 

available: high-efficiency gas storage, gas condensing, gas tankless, 

solar, and heat pump water heaters. (For lists of qualifying products, 

see www.energystar.gov/index.cfm?c=water_heat.pr_water_heaters.)

Conventional Storage Water Heaters

Conventional gas or electric storage water heaters offer a ready 

reservoir (storage tank) of hot water. The lowest-priced storage water 

heater may be the most expensive to operate and maintain over its 

lifetime. While an oversized unit may be alluring, it carries a higher 

purchase price and increased energy costs due to higher standby 

energy losses. Information on properly sizing a water heater is 

available on the DOE Energy Savers website www.energysavers.gov. 

Storage heaters work best with steady, continuous use patterns.

Gas combustion storage water heaters should be either power vented, 

which forcibly discharges the products of combustion and draws 

combustion air from the house; direct vented with dedicated outside 

air for combustion; or sealed combustion units that draw combustion 

air from outdoors and fan discharge combustion exhaust outdoors.

Electric storage heaters are generally the most expensive to operate 

unless rates are very low. Builders should specify the most efficient unit 

possible and consider the use of solar thermal systems, a propane- or 

gas-fired instantaneous water heater, or a heat pump water heater.

Tankless Water Heaters

Tankless water heaters provide hot water only as it is needed. They have 

no tank and so do not have the standby energy losses associated 

with storage water heaters. Typically, tankless water heaters provide 

hot water at a rate of 2 to 5 gallons (7.6–15.2 liters) per minute. If the 

demand for hot water does not exceed the heater’s ability to produce it, 

tankless water heaters do not run out of hot water. Gas-fired tankless 

water heaters produce higher flow rates than electric tankless heaters. 

Because of their heat-on-demand nature, electric versions can create 

Water Heater Efficiency

The current DOE standard for water 

heaters went into effect in 2004. 

DOE published a final rule for amended 

standards for residential water heaters on 

April 16, 2010, which will become effective 

April 16, 2015, for products manufactured 

on or after April 16, 2015. The required 

energy factor (EF) varies depending on 

the type of water heater and the rated 

storage volume: 

Gas ≤55 gal EF.............................0.675

Gas >55 gal EF.............................0.8012

Electric ≤55 gal EF......................0.960

Electric >55 gal EF......................2.057

Instantaneous Gas EF ................0.820

Instantaneous Electric EF .........0.930

For the most common sized electric water 

heater (50 gallons) the new standard will 

save 4%; for the most common gas water 

heater size (40 gallons) the new standard will 

save 3%. For gas-fired and electric storage 

water heaters that are over 55 gallons, the 

standards will effectively require electric 

storage water heaters to be air source 

heat pump water heaters and gas storage 

water heaters will have to use condensing 

technology (DOE 2011; ASAP 2011).

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Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 9.21
high peak loads for electric utilities. In areas where utilities charge more 

for electricity at peak times, these systems could be especially expensive 

for consumers. 

Gas-fired tankless water heaters have been used in many Building 

America homes. They are readily available and are a mature 

technology. In addition to energy savings, other benefits include small 

size and longer life expectancy. One disadvantage of these units is the 

time needed for a cold unit to reach operating temperature. This brief 

warm-up time results in a slight delay in hot water delivery (10 to 20 

seconds) and associated water waste. Builders considering installing 

tankless gas water heaters in a development need to plan for adequate 

gas line size. Tankless water heaters draw approximately 150,000 

Btus compared to a standard water heater that draws 35,000 Btus. 

Therefore, much higher capacity is demanded of the gas lines during 

peak usage times, such as in the morning.

Air Source Heat Pump Water Heaters

Air source heat pump water heaters use electric compressors and 

pumps to move heat from the environment to the water tank. 

Although they use electricity, they can be two to three times more 

energy efficient than conventional electric resistance water heaters. 

One manufacturer estimates $320 savings per year in water heating 

costs when comparing their ENERGY STAR heat pump water heater, 

which uses 1,856 kWh/yr, to a standard 50-gallon electric tank water 

heater, which uses 4,881 kWh/yr. 

Because the heat pump water heater draws in air from the room to 

heat water, some manufacturers recommend that the room the water 

heater is located in be at least 10 ft x 10 ft x 7 ft (700 cubic feet). If the 

room is smaller than 700 cubic feet, the room must have a louvered 

door or a door that has vents installed near the top and bottom. Each 

of these vents should have an area of 240 square inches. The units 

themselves are approximately 63 inches tall by 24 inches wide. 

Because they have a fan, heat pump water heaters do make some 

noise; noise is related to fan speed, the faster the fan speed the more 

sound is likely. Fans speeds will increase when ambient temperatures 

are colder and when tank temperature is lower. In parts of the mixedhumid climate that are cooling-dominated, the best location for a heat 

pump water heater is in the garage. In heating-dominated regions, it 

can be located in a heated basement or utility room. The water heater 

pulls heat from the air and may help reduce cooling loads in the 

summer in the area of the home where it is located. 

One concern with heat pump water heaters is their recovery rate. The 

water heater industry typically measures the recovery rate of a water 

(top) Building America builder Tommy 

Williams Homes installs tankless gas-fired 

water heaters to save energy by eliminating 

the stand-by losses inherent with storage 

tank water heaters.

(bottom) Air-source heat pump water 

heaters are now commercially available 

like this one seen at the 2010 International 

Builders Show.

CHAPTER 9 / BUILDING AMERICA BEST PRACTICES SERIES

9.22 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
heater by its first hour delivery (FHD) of hot water. Natural gas 

and liquid propane water heaters are capable of heating water more 

quickly than electric water heaters (standard electric or heat pump), 

and therefore, have quicker recovery rates. A 50-gallon gas water 

heater has an FHD of 80-90 gallons. A 50-gallon electric standard 

or heat pump water heater has an FHD of 58-65 gallons. Many heat 

pump water heaters are hybrid models that use electric elements to 

provide back-up heat. These can assist with recovery rates. Another 

solution is to get a slightly larger tank than you would typically size, 

for example a 50-gallon rather than 40-gallon tank.

Solar Water Heaters

Solar thermal water heaters use the sun’s heat to provide hot water. 

These systems usually include one or two collectors that typically sit 

on a house’s roof and resemble skylights.

There are four main types of solar water heating systems:

•	 Glazed flat-plate collectors are the most common and can be used 

in any climate with proper design.

•	 Evacuated tube collectors use thermos-like evacuated glass tubes. 

Some also use heat pipes with a special fluid that vaporizes at high 

temperatures. These collectors tend to be more expensive than 

other collectors but operate efficiently at high temperatures and 

can be used in very cold climates with proper design.

P/T

Relief

Valve

Drain Valve

Pressure Relief Valve

Shut-Off Valve

COLD WATER IN HOT WATER OUT

Drain

Wrap Around 

Heat Exchanger

Sight

Glass

Pump

Drain

(top) Flat plate collector-style solar water 

heaters are shown mounted on the roof 

along with solar photovoltaic panels. 

(Photo Source: Florida Solar Energy Center)

(left) This solar water heater is a drainback 

active, indirect system that uses water or 

a water and propylene–glycol mixture as 

the heat transfer fluid. Fluid in the roof-top 

collector and pipes drains into a reservoir 

inside the house when the hot water tank 

has reached the desired temperature or 

when the pump shuts off; thus protecting 

the system from both overheating or 

freezing. This feature makes this system a 

suitable option for the mixed-humid climate.

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CHAPTER 9. MECHANICAL, PLUMBING, AND ELECTRICAL SYSTEMS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 9.23
•	 Integrated collector storage systems combine a collector with a 

storage tank. These systems are one of the lowest cost but should 

only be used where there is no chance of freezing.

•	 Unglazed flat plate collectors are simple systems that consist of plastic 

surfaces incorporating channels for water to flow through. Some 

manufacturers are offering unglazed collectors for domestic hot water. 

Their traditional use has been for pool and spa heating. Every swimming 

pool with a solar exposure should be equipped with a solar pool heater.

Swimming Pools

There are more than 5 million in-ground pools in the United 

States and many of them are located in the hot-humid climate. 

The typical in-ground swimming pool can consume up to 25% of a 

home’s electricity use, canceling out the savings of energy-efficient 

construction. There are several steps you can take to improve 

pool efficiency. First replace the standard pool pump motor with 

a high-efficiency model. Standard models typically draw 2,000 to 

2,200 watts of electricity, consuming about 12 kWh per day. New 

variable-speed pumps, which cost about $1,200 to $1,500 installed 

can cut energy use by 75% compared to single-speed models. While 

single-speed pool pumps consume about 10 to 12 kWh per day of 

electricity, variable-speed pumps usually draw about 120 to 180 

watts on low speed and consume about 2 kWh per day (Easley 

2010). These high-efficiency pumps tend to last longer, reduce peak 

demand, are more quiet, put less stress on the pool’s plumbing 

system, and provide better filtration. They can also be configured to 

accommodate cleaners that can run without a booster pump, which 

can save an additional 1,000 kWh per year (Easley 2010). Other ways 

to save energy with pools include installing a solar thermal water 

heater, installing LED pool lights, and providing a pool thermal 

blanket to retain heat in cooler seasons. To save water, cartridge 

filters should be installed rather than sand or diatomaceous earth 

filters which require periodic flushing with large amounts of water.

For More Information on Plumbing and Water Heating

ASAP. 2011. “Water Heaters” Appliances Standards Awareness Project, accessed September 18, 

2011, www.appliance-standards.org/product/water-heaters

DOE. 2007. Volume 6 - Building America Best Practices Series – High Performance Home 

Technologies: Solar Thermal & Photovoltaic Systems. Washington, D.C. www.buildingamerica.gov

DOE. 2007. A Consumer’s Guide to Energy Efficiency and Renewable Energy. 

“Water Heating,” U.S. Department of Energy 

www.eere.energy.gov/consumer/your_home/water_heating/index.cfm/mytopic=12770

DOE. 2011. 7.5.3 Efficiency Standards for Residential Water Heaters,” Building Energy Data Book, 

last updated March 2011. http://buildingsdatabook.eere.energy.gov/TableView.aspx?table=7.5.3

DOE. 2011. “Sizing Water Heaters,” Energy Savers, U.S. Department of Energy, 

www.energysavers.gov

(top) If you are installing a swimming 

pool, consider energy saving features 

like a high-efficiency pump, solar water 

heating, and LED lighting.

(bottom) Pool pumps equipped with 

variable-speed motors can reduce 

electricity use 75% compared to standard 

single-speed pool pumps.

(Photo Source: Steve Easley)

CHAPTER 9 / BUILDING AMERICA BEST PRACTICES SERIES

9.24 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
ENERGY STAR. High-Efficiency Water Heaters Provide Hot Water for Less. U.S. 

Environmental Protection Agency, Washington, D.C. www.energystar.gov/ia/new_homes/

features/WaterHtrs_062906.pdf

Easley, Steve. 2010. Secret Energy Hog, GreenBuilder Magazine, October 2010. 

www.greenbuildermag.com

2009 IRC. 2009. International Residential Code - One and Two-Family Dwellings, Section 

403.4, “Circulating Hot Water Systems,” International Code Council (ICC), Washington, D.C. 

www.iccsafe.org/Store/Pages

NAHBRC. Undated. Toolbase Technotes. Cross-Linked Polyethylene PEX in Residential 

Plumbing Systems. National Association of Home Builders Research Center

www.toolbase.org/PDF/DesignGuides/TechNote_Pex.pdf

Solar Rating and Certification Corporation, www.solar-rating.org.

Wiehagen J. and J.L. Sikora. 2003. Performance Comparison of Residential Hot Water 

Systems. NREL/SR-550-32922. National Renewable Energy Laboratory. Golden, CO. 

www.buildingamerica.gov

High-Performance Lighting

Lighting accounts for an estimated 15% of electricity use in the 

typical American home (DOE 2009). The typical incandescent lamp 

wastes 90% of the energy it uses producing heat rather than light. 

High-performance lighting, including CFL and LED products, 

provides excellent visual quality that is also very energy efficient. 

Residential lighting controls represent a significant opportunity for 

energy savings. Lighting controls generally refer to technologies that 

turn off (or turn down) lighting systems when they are not needed. 

Examples include occupancy sensors, vacancy sensors, photo 

sensors, dimmers, and timers.

CFLs and LEDs

Compact fluorescent lamps (CFLs) use 70%-75% less energy than 

their incandescent equivalents with comparable brightness and 

color rendition. They cost more, but last 10 to 13 times longer than 

incandescent lamps, making them cost effective if used at least 

2-3 hours per day. Compact fluorescent lamps come in both pinbased models and screw-based models that fit most standard fixtures 

found in homes today. ENERGY STAR first established criteria 

for CFL lamps in 2007. Today thousands of models of ENERGY 

STAR-labeled CFL bulbs and fixtures are available in a wide variety 

of sizes, shapes, and color renditions. 

[The 2009 IECC 404.1 requires that at least 50% of the lamps in 

permanently installed lighting fixtures be high-efficacy lamps. 

The 2012 IECC R404.1 increases this requirement to 75%. 

ENERGY STAR Version 3.0 requires 80% of fixtures to contain 

Energy-efficient ENERGY STAR-rated 

fixtures come in many attractive styles, 

like these CFL-based fixtures. 

(Photo source: Progress Lighting)

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CHAPTER 9. MECHANICAL, PLUMBING, AND ELECTRICAL SYSTEMS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 9.25
ENERGY STAR-qualified CFLs, LEDs, or pin-based lamps.] 

Building America recommends 100% high-efficacy lamps. Almost all 

fluorescent lamps equipped with electronic ballasts qualify as highefficacy light sources. LEDs and metal halide lamps can also be high 

efficacy. Incandescent, quartz halogen, low-voltage halogen reflector, 

and mercury vapor lamps do not qualify as high efficacy. 

Light emitting diode (LED) lights are becoming more commonplace 

as new models are developed with better lighting performance, higher 

efficiency, and lower cost. DOE tracks and tests LED products as 

they enter the market via its CALiPER program and other lighting 

programs (see www.ssl.energy.gov). ENERGY STAR criteria for 

solid-state lighting (LED) went into effect in September 2008. To earn 

the ENERGY STAR label, LED products have to offer a three-year 

warranty and meet stringent performance requirements for color 

rendering, luminaire efficiency, and light output over the life of the 

lamp, which is at least 25,000 hours for indoor, residential products.

DOE partners with lighting organizations to host two CFL and 

LED lighting design competitions. Next Generation Luminaires 

(www.ngldc.org) and the L-Prize (www.lightingprize.org). The 

American Lighting Association, the Consortium for Energy 

Efficiency, and Underwriters Laboratory host a third competition, 

Lighting for Tomorrow (www.lightingfortomorrow.com). Visit the 

competition websites to see competition winners, including some of 

the most energy-efficient, eye-catching designs on the market. 

Recessed Can Lights

Recessed “can” ceiling fixtures, or downlights, that are recessed into 

insulated ceilings are required [by the 2009 IECC 402.4.5 and the 2012 

IECC 402.4.4] to be rated for insulation contact (so that insulation 

can be placed over them). The housing of the fixture should be 

airtight to prevent conditioned air from escaping into the ceiling 

cavity or attic, and unconditioned air from infiltrating from the 

ceiling or attic into the conditioned space. [Per the 2009 IECC 402.4.5 

and the 2012 IECC 402.4.4] the fixture should bear a label showing it 

meets the ASTM E 283 guideline of ≤2.0 cfm of air movement from 

the conditioned space to the ceiling cavity when tested at 75 Pa and 

the housing should be caulked or gasketed where it meets the ceiling. 

IC-rated downlight fixtures are available for CFL lamps.

These CFL-based lights designed by Maxlite 

won grand prize in the 2008 Lighting 

for Tomorrow design competition cosponsored by DOE. (Photo source: Maxlite)

LED fixtures are becoming more efficient 

and affordable and are now available in 

several applications for homes like the 

under-cabinet, in-cabinet, and spot 

lighting shown here.

For More Information 

on Lighting

California Energy Commission. 2009. 

California’s Energy Efficiency Standards for 

Residential and Nonresidential Buildings: Title 24. 

Sacramento, CA. www.energy.ca.gov/title24/

California Lighting Technology Center.

www.cltc.ucdavis.edu

ENERGY STAR. 2007. Light Bulbs and Fixtures 

website. www.energystar.gov

IBACOS. High-Performance Lighting Guide 

website www.ibacos.com

U.S. Department of Energy. Solid-State Lighting 

(SSL) website www.ssl.energy.gov

CHAPTER 9 / BUILDING AMERICA BEST PRACTICES SERIES

9.26 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Example of Recessed Downlight Performance Using 

Different Lighting Sources

MEASURE

INCANDESCENT* FLUORESCENT* LED**

65W R-30 Halogen

13W triple 

tube Spiral 

CFL

15W R-30 

CFL

LED 

downlight 

Delivered light output 

(lumens), initial 678 466 653 697

Luminaire wattage 

(nominal W) 65 10 13 6.4

Luminaire efficacy

(lm/W) 11 46 49 109

Price (average prices 

as of Aug 2009) $3 $8 $5 $80

Life Span 2,500 hrs 12,000 hrs 6,000 hrs 50,000 hrs

*Based on photometric and lamp lumen rating data for products available 

July 2010. Actual downlight performance depends on reflectors, trims, lamp 

positioning, and other factors. Assumptions available from PNNL.

**LED fixture was the LR6 model by Cree. It was tested through the DOE 

CALiPER light testing program. For more information about CALiPER, see 

www.ssl.energy.gov.

Appliances

When it comes to selecting appliances and electronic equipment, 

look for the EnergyGuide and ENERGY STAR labels. Building 

America recommends using best-in-class products for appliances 

that are not currently rated by ENERGY STAR. 

EnergyGuide Label

The Federal Trade Commission requires EnergyGuide labels on 

most home appliances (except for stove ranges and ovens, and home 

electronics, such as computers, televisions, and home audio equipment). 

EnergyGuide labels provide an estimate of the product’s energy 

consumption or energy efficiency. They also show the highest and lowest 

energy consumption or efficiency estimates of similar appliance models.

ENERGY STAR Label

ENERGY STAR labels appear on appliances and 

home electronics that meet strict energy efficiency 

criteria established by the U.S. Department 

of Energy and U.S. Environmental Protection 

Agency. The ENERGY STAR labeling program 

includes most home electronics and appliances 

except for stove ranges and ovens.

The EnergyGuide label helps 

consumers compare the 

energy efficiency of appliances

Estimated energy consumption 

on a scale showing a range for 

similar models

Estimated yearly operating cost 

based on the national average cost 

of electricity.

For More Information 

on ENERGY STAR and 

EnergyGuide Labeling

California Energy Commission Consumer 

Energy Center “EnergyGuide,” 

www.consumerenergycenter.org/home/

appliances/energyguide.html

ENERGY STAR. www.energystar.gov

ENERGY STAR Windows. 

www.efficientwindows.org/energystar.cfm

SRP. “Energy Guide Labels help you compare,” 

www.srpnet.com/energy/energyguide.aspx

The U.S. Department of Energy “Best Practices” 

Builders Guides www.eere.energy.gov/buildings/

building_america/

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CHAPTER 9 / BUILDING AMERICA BEST PRACTICES SERIES

9.28 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Chapter 10.

Occupant Health 

and Safety

As houses become tighter, indoor air quality becomes a more 

important issue. To address occupant health and safety, the EPA 

has developed the Indoor airPlus label. The Indoor airPlus checklist 

is shown at the end of this chapter. The EPA recommends these 

actions (www.epa.gov/indoorairplus): 1) moisture control including 

improved control of condensation and better roof, wall, and 

foundation drainage; 2) radon control including testing and radon 

abatement techniques; 3) pest management including caulking, 

sealing, and screening at entry points; 4) a properly engineered 

HVAC system including sealed ducts, and whole-house and spot 

ventilation; 5) combustion venting including installing sealed 

combustion heating equipment and carbon monoxide detectors, 

and sealing and ventilating attached garages; and 6) choosing 

low-chemical-content materials, keeping materials dry during 

construction, and airing out the home prior to move in. Many of 

these recommendations are addressed in this guide; see Chapter 8 

for actions 1, 2, and 3; see Chapter 9 for actions 4 and 5. 

Best practices for health and safety include the following:

•	 Use only sealed-combustion or power-vented appliances in the 

conditioned space. Specifically, Building America recommends 

that any combustion furnace inside conditioned space should be a 

sealed-combustion 90%+ (AFUE of 90 or greater) unit. Any water 

heater inside conditioned space should be sealed-combustion, 

direct-vented, or power-vented.

•	 Choose high-efficiency water heaters. Don’t install atmosphericventing water heaters inside the home. These appliances draw air from 

the room in which they are located and depend on the stack effect to 

establish an exhaust draft, but the stack effect can be overcome by 

dryers, exhaust fans, supply duct leakage, or other conditions that 

depressurize the house, causing back drafting of exhaust gases. 

(top) Some cabinet makers are now 

specializing in low-VOC cabinetry to meet 

growing consumer demand.

(bottom) Several low-VOC adhesives

are now available. 

Dryer vent exhausts must have a closeable 

gravity or automatic damper. A single hinged 

door with a 21⁄2-inch effective opening is not 

as effective as a louvered damper.

louvered damper

with hood

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CHAPTER 10. OCCUPANT HEALTH AND SAFETY

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 10.1
•	 Install carbon monoxide detectors (hard-wired units) (at one per 

every approximately 1,000 square feet) in any house containing 

combustion appliances and/or an attached garage, and even in 

those houses with no combustion appliances in case one should 

be installed at a future date. [NFPA 720 says CO detectors shall 

be installed near bedrooms, and on every occupiable level of a 

dwelling unit, including basements, excluding attics and crawl 

spaces. NFPA 101 Section 24.3.4.1 requires smoke alarms in all 

sleeping rooms, outside of each separate sleeping area, in the 

immediate vicinity of the sleeping rooms, and on each level of 

the dwelling unit, including basements.]

•	 Vent all exhaust fans directly to the outside, not into the attic. 

Equip outdoor air intakes and exhaust vents with automatic or 

gravity dampers that close when the ventilation system is not in 

operation [per 2009 IECC 403.5]. Kitchen fans should ventilate at 

a rate of 100 cfm intermittent or 25 cfm continuous; bathroom 

fans should ventilate at a rate of 20 cfm continuous or 50 cfm 

intermittent [2009 IRC Table M1507.3]. Range hoods capable of 

exhausting more than 400 cfm must provide makeup air at a rate 

equal to the exhaust air rate [2009 IRC M1503.4]. Use energyefficient and quiet fans (see Chapter 9, ventilation section).

•	 Vent clothes dryers and central vacuum cleaners directly outdoors. 

Smooth, rigid metal ducts with louvered vents and straight runs 

provide the most efficient ducting systems. Check code [2009 

IRC M1502.4.4] and manufacturer’s specifications for limits on 

dryer duct length. Avoid sags in ducts. Insulate ducts to avoid 

condensation; flash and caulk wall penetrations. Vinyl, nylon, and 

foil ducts do not meet code [2009 IRC M1502].

•	 Provide filtration for forced air systems that provide a minimum 

atmospheric dust spot efficiency of 30% or MERV of 8 or higher. 

MERV (Minimum Efficiency Reporting Value) is a measure of 

an air filter’s efficiency at removing particles. [This exceeds the 

ASHRAE 62.2-2010 6.7 recommended MERV 6 or better.]

•	 Maintain indoor humidity in the range of 30% to 50% by controlled 

mechanical ventilation, mechanical cooling, or dehumidification. 

•	 Maximize hard surface areas (tile, vinyl, hardwood) to better 

manage dust for health purposes. 

• Install a central (also known as “whole-house”) vacuum system 

that exhausts to the outdoors, to facilitate cleaning and minimize 

reintroduction of vacuumed dust.

(top) This fresh air intake has a mechanical 

damper to control the intake of fresh 

outside air into the air handler for 

distribution via the central HVAC system.

(bottom) Atmospheric venting water 

heaters, like the one shown here, can 

backdraft through the opening at the base 

of the flue. Use of closed-combustion 

appliances eliminates this risk. 

CHAPTER 10 / BUILDING AMERICA BEST PRACTICES SERIES

10.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
•	 Provide occupants with information on safety and health related 

to HVAC equipment, hot water, and lighting. 

•	 Isolate attached garages from conditioned spaces [per 2009 

IECC 402.4.1 and ASHRAE 62.2-2010, 6.5.1]. Common walls and 

ceilings between attached garages and living spaces should be visually 

inspected to ensure they are air-sealed before insulation is installed. All 

connecting doors between living spaces and attached garages should 

include an automatic closer, and they should be installed with gasket 

material or be made substantially air-tight with weather stripping.

•	 Install an exhaust fan in attached garages with a minimum 

installed capacity of 70 cfm that is rated for continuous operation. 

Vent the fan directly outdoors. If automatic fan controls are 

installed, they should activate the fan whenever the garage is 

occupied and for at least 1 hour after the garage has been vacated. 

The fan carries pollutants outside and creates a negative pressure 

that helps stop garage air from migrating into the house.

•	 If gas or wood fireplaces are included, install units that have a 

dedicated outside air intake for combustion air, directly vent 

effluents outside, and are equipped with tight-fitting glass doors. 

•	 Use low-VOC (volatile organic compound) paints, finishes, 

varnishes, and adhesives whenever possible. Keep windows open 

while paints and adhesives are applied and until they are dry to 

dissipate initial concentrations.

For More Information on Healthy Homes 

and Combustion Safety

American Lung Association. 2008. “Health House: Builder Guidelines.” ALA, Saint Paul, MN. 

www.healthhouse.org/build/2008HHbuilderguidelines.pdf

American Lung Association. “Health House Tipsheet on Backdrafting,” ALA, Saint Paul, MN. 

www.healthhouse.org/tipsheets/TS_backdrafting.pdf

ASTM D6670 – 01. 2007. “Standard for Full-Scale Chamber Determination of Volatile 

Organic Emissions from Indoor Materials/Products,” 

www.astm.org/Standards/D6670.htm

Building Performance Institute, Inc., 2007. “Combustion Safety Test Procedure for Vented 

Appliances,” www.bpi.org/documents/Gold_Sheet.pdf

California Air Resource Board (CARB). “Airborne Toxic Control Measure (ATCM) to Reduce 

Formaldehyde Emissions from Composite Wood Products” Fact Sheet, 

www.arb.ca.gov/toxics/compwood/factsheet.pdf

California Air Resource Board (CARB). “Regulation for Reducing Volatile Organic 

Compound Emissions from Consumer Products,” available online at 

www.arb.ca.gov/consprod/regs/cp.pdf

Consumer Product Safety Commission (CPSC). What You Should Know About Combustion 

Appliances and Indoor Air Pollution (CPSC Document #452), 

www.cpsc.gov/cpscpub/pubs/452.html

DOE. 2011. [draft] Workforce Guidelines for Home Energy Upgrades. Prepared by the National 

Renewable Energy Laboratory for the DOE. www.eere.energy.gov/wip/retrofit_guidelines.html

This Building America home used lowVOC paints and finishes (like those shown 

in lower photo) to meet local green 

building guidelines.

American Lung Association: 

Nine Features of a Healthy House

•	 Foundation waterproofing and

moisture control

•	 Advanced framing techniques

•	 Air sealing and advanced

insulation techniques

•	 Energy-efficient,

high-performance windows

•	 Energy-efficient and sealed

combustion appliances

•	 High-efficiency air filtration

•	 Whole house ventilation

•	 Humidity control

•	 Low-VOC interior finishes.

(Source: Health House, American Lung 

Association of the Upper Midwest, 

www.healthhouse.org/build/components.cfm)

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CHAPTER 10. OCCUPANT HEALTH AND SAFETY

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 10.3
EPA. 2010. Healthy Indoor Environmental Protocols for Home Energy Upgrades. updated 

September 9, 2010. www.epa.gov/iaq/homes/retrofits.html

Florida Solar Energy Center. 2007. “Indoor Air Quality,” available at 

www.fsec.ucf.edu/en/consumer/buildings/homes/airqual.htm

Greenguard Environmental Institute. www.greenguard.org

International Code Council, Inc., “UL 2034 History – CO Alarms,” May 4, 2005. 

www.iccsafe.org/cs/cc/ctc/CO/CO_UL2034History.pdf

National Association of Home Builders Research Center. “Low- or No-VOC Paints, Finishes 

and Adhesives,” www.toolbase.org/Home-Building-Topics/Indoor-Air-Quality/low-voc-paints

National Green Building Standard 901.10, August 10, 2007, pg. 70. 

www.nahbgreen.org/Guidelines/ansistandard.aspx

NFPA 720: Standard for the Installation of Carbon Monoxide (CO) Warning 

Equipment in Dwelling Units. www.nfpa.org/aboutthecodes/AboutTheCodes.

asp?DocNum=720&Cookie%5Ftest=1

Raub, J. A., M. Mathieunolf, N. B. Hampson, and S. R. Thom. 2000. “Carbon Monoxide 

Poisoning—a Public Health Perspective.” Toxicology (145):1-14. 

www.ncbi.nlm.nih.gov/pubmed/10771127

South Coast Air Quality Management District. Rule 1168 – Adhesive and Sealant Application. 

www.arb.ca.gov/DRDB/SC/CURHTML/R1168.pdf

Sustainable Buildings Industry Council (SBIC). 2003. Green Building Guidelines: Meeting the 

Demand for Low-Energy, Resource-Efficient Homes. U.S. DOE. Washington, D.C. document 

available at www.sbicouncil.org/storeindex.cfm 

The American Lung Association. Health House tipsheet on carbon monoxide 

www.healthhouse.org/tipsheets/TS_CarbonMonoxide.pdf

The American Society of Heating, Refrigerating, and Air-Conditioning Engineers 

(ASHRAE). Top Ten Things that homeowners can do to provide good indoor air quality. 

www.contractorconnect.net/GoodAir.html

UL 2034. 1996. Standard for Single and Multiple Station Carbon Monoxide Alarms, Edition 2, 

October 29, 1996. www.alliedsalescompany.com/ul/2034.pdf

University of Illinois Extension Service. “Five Steps to a Healthier Garage,” 

http://web.extension.uiuc.edu/will/factsheets/family116.html

U.S. Department of Energy. “The House as a System: Combustion Safety,” 

www.eere.energy.gov/buildings/building_america/pdfs/db/31046.pdf

U.S. Environmental Protection Agency. 2009. “Indoor airPLUS Construction Specifications,” 

www.epa.gov/indoorairplus

U.S. Environmental Protection Agency. “Indoor Air Quality Carbon Monoxide Fact Sheet,” 

www.epa.gov/iaq/co.html

U.S. Environmental Protection Agency. “Wood Coating Case Studies by Company,” 

www.epa.gov/ttn/atw/wood/low/casebyco.html

U.S. Green Building Council, LEED for Homes. 2008. 

www.greenhomeguide.org/documents/leed_for_homes_rating_system.pdf

(top) Insight Homes meets the strict 

requirements of the American Lung 

Association Healthy House program, which 

include a whole-house dehumidifier and 

central vacuum system. Its homes also meet 

the requirements of ENERGY STAR’s Indoor 

AirPlus Package.

(bottom) Pine Mountain Builders builds 

detached garages, which keeps fumes out 

of the house. Inside the homes, the builder 

uses low-VOC paints and carpets and installs 

carbon monoxide detectors. Houses sit on 

raised slabs to protect the home from water 

damage and avoid crawlspace moisture issues.

CHAPTER 10 / BUILDING AMERICA BEST PRACTICES SERIES

10.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Indoor airPLUS Verification Checklist

 Address or Div/Lot#: 

 City/State/Zip: Date: Verified by

Section Requirements (see Indoor airPLUS Construction Specifications for details) N/A Builder Rater

 Water-Managed Site and Foundation 

 1.1 Site & foundation drainage: sloped grade, protected drain tile, & foundation floor drains o	 o

 1.2 Capillary break below concrete slabs & in crawlspaces (Exception - see specification) o	 o	 o

 1.3 Foundation wall damp-proofed or water-proofed (Except for homes without below-grade walls) o	 o	 o

 1.4 Basements/crawlspaces insulated & conditioned (Exceptions - see specification) o	 o	 o

 Water-Managed Wall Assemblies 

 1.5 Continuous drainage plane behind exterior cladding, properly flashed to foundation o	 o

 1.6 Window & door openings fully flashed o	 o

 Water-Managed Roof Assemblies 

 1.7 Gutters/downspouts direct water a minimum of 5' from foundation (Except in dry climates) o	 o	 o

 1.8 Fully flashed roof/wall intersections (step & kick-out flashing) & roof penetrations o	 o

 1.9 Bituminous membrane installed at valleys & penetrations (Except in dry climates) o	 o	 o

 1.10 Ice flashing installed at eaves (Except in Climate Zones 1 - 4) o	 o	 o

 Interior Water Management 

 1.11 Moisture-resistant materials/protective systems installed (i.e., flooring, tub/shower backing, & piping) 	 	 	o

 1.12 No vapor barriers installed on interior side of exterior walls with high condensation potential o		 o

 1.13 No wet or water-damaged materials enclosed in building assemblies o		 o

 2.1 Approved radon-resistant features installed (Exception - see specification) o		 o 	 o

 2.2 Two radon test kits & instructions/guidance for follow-up actions provided for buyer (Advisory-see specification) o		 o 	 o

 3.1 Foundation joints & penetrations sealed, including air-tight sump covers o

 3.2 Corrosion-proof rodent/bird screens installed at all openings that cannot be fully sealed (e.g., attic vents) o		 o

 4.1 HVAC room loads calculated, documented; system design documented; coils matched o

 4.2 Duct system design documented & properly installed OR duct system tested (check box if tested) o o		 		 o

 4.3 No air handling equipment or ductwork installed in garage; continuous air barrier required in adjacent assemblies o

 4.4 Rooms pressure balanced (using transfer grills or jump ducts) as required OR tested (check box if tested) o o			 o

 4.5 Whole house ventilation system installed to meet ASHRAE 62.2 requirements o

 4.6 Local exhaust ventilation to outdoors installed for baths, kitchen, clothes dryers, central vacuum system, etc. o

 4.7 Central forced-air HVAC system(s) have minimum MERV 8 filter, no filter bypass, & no ozone generators o

 4.8 Additional dehumidification system(s) or central HVAC dehumidification controls installed (In warm-humid climates only) o			 o

 Combustion Source Controls 

 5.1 Gas heat direct vented; oil heat & water heaters power vented or direct vented (Exceptions - see specifications) o			 o

 5.2 Fireplaces/heating stoves vented outdoors & meet emissions/efficiency standards/restrictions o			 o

 5.3 Certified CO alarms installed in each sleeping zone (e.g., common hallway) according to NFPA 720 o

 5.4 Smoking prohibited in common areas; outside smoking at least 25' from building openings (Multi-family homes only) o		 o 	 o

 Attached Garage Isolation 

 5.5 Common walls/ceilings (house & garage) air-sealed before insulation installed; house doors gasketed & closer installed o			 o

 5.6 Exhaust fan (minimum 70 cfm, rated for continuous use) installed in garage & vented to outdoors (controls optional) o			 o

 6.1 Certified low-formaldehyde pressed wood materials used (i.e., plywood, OSB, MDF, cabinetry) o		 o

 6.2 Certified low-VOC or no-VOC interior paints & finishes used o		 o

 6.3 Carpet, adhesives, & cushion qualify for CRI Green Label Plus or Green Label testing program o		 o 	 o

 7.1 HVAC system & ductwork verified dry, clean, & properly installed o

 7.2 Home ventilated before occupancy OR initial ventilation instructions provided for buyer o		 o

 7.3 Completed checklist & other required documentation provided for buyer o		 o

Rater/Provider: Builder: 

 Company: Company: 

 Signature: Signature: Moisture Control Combustion Pollutants Pests HVAC Final Radon Materials

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CHAPTER 10. OCCUPANT HEALTH AND SAFETY

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 10.5
Guidance for Completing the Indoor airPLUS Verification Checklist:

1. Only ENERGY STAR qualified homes verified to comply with these specifications can earn the Indoor airPLUS label. See Indoor 

airPLUS Construction Specifications for full descriptions of the requirements, terms, exceptions, abbreviations, references, and 

climate map used in this checklist. Verification is not complete until this checklist is completed in full and signed.

2. Check one box per line. Check “N/A” for specifications that do not apply for specific conditions (e.g., climate) according to the

Exceptions described in the Indoor airPLUS Construction Specifications. Check either “Builder” or “Rater” for all other items 

to indicate who verified each item. Items may be verified visually on site during construction, by reviewing photographs taken 

during construction, by checking documentation, or through equivalent methods as appropriate. If using a performance testing 

alternative to meet requirement 4.2 or 4.4, the box marked “Tested” must be checked and testing documentation must be provided in the Home Energy Rating System/Builder Option Package (HERS/BOP) file.

3. The rater who conducted the verification, or a responsible party from the rater’s company, must sign the completed verification 

checklist. The builder must sign the checklist if any items in the “Builder” column are checked, and by so doing accepts full 

responsibility for verifying that those items meet Indoor airPLUS requirements.

4. The builder provides one copy of the completed and signed checklist for the buyer. The HERS/BOP provider or rater files a copy 

with HERS/BOP and ENERGY STAR documentation (e.g., Thermal Bypass Checklist) for the home. 

5. The checklist may be completed for a batch of homes using a RESNET-approved sampling protocol when qualifying homes as 

ENERGY STAR. For example, if the approved sampling protocol requires rating one in seven homes, then the checklist will be 

completed for the one home that was rated. 

Note: The Indoor airPLUS Construction Specifications are designed to help improve indoor air quality (IAQ) in new homes compared with homes built 

to minimum code. These measures alone cannot prevent all IAQ problems; occupant behavior is also important. For example, smoking indoors would 

negatively impact a home’s IAQ and the performance of the specified Indoor airPLUS measures.

 

Notes: 

For further information on the Indoor airPLUS program, visit epa.gov/indoorairplus.

All Indoor airPLUS qualified homes meet strict 

guidelines for energy efficiency set by ENERGY STAR, 

the nationally-recognized symbol for energy efficiency. 

Qualified homes earn the 

Indoor airPLUS label. 

Place it next to the 

ENERGY STAR label.

CHAPTER 10 / BUILDING AMERICA BEST PRACTICES SERIES

10.6 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Building America believes in real results. The only way to confirm 

results is to test for them. Therefore, in addition to required 

inspections by the code inspector, Building America recommends 

that site supervisors conduct systematic inspections during the 

course of construction, and that a formal commissioning be 

conducted before handing the keys to the new homeowners. The 

steps described in this chapter will confirm your workmanship, 

giving you peace of mind while reducing the likelihood of costly 

callbacks. Some of the activities recommended here are now 

required by the 2009 IECC, as noted in green in this section. 

These commissioning steps can reduce callbacks and litigation 

risks for builders:

•	 Develop a commissioning plan appropriate to the home and 

the equipment installed.

•	 Test every house.

•	 Review commissioning results with installers.

•	 Provide the homeowner with information on the proper operation 

and maintenance of mechanical systems and other equipment. 

Walk-Throughs during Construction

General walk-throughs and inspections are especially good at 

critical times during construction before the next step makes it 

impossible to detect a problem or make a repair. If the wholehouse approach is new to your subcontractors, you should conduct 

multiple inspections to ensure that the subcontractors have 

understood what is required of them and how to implement it. 

After the process has become more routine, you might get by with 

spot inspections. HotSpot inspections done by the site supervisor 

Chapter 11.

Inspecting, Testing, 

and Commissioning

CHAPTER TOPICS

11.1 Walk-Throughs 

during Construction

11.2 Building Commissioning

Duct blaster testing confirms that ducts 

are well sealed (Photo source: PNNL).

Building America recommends that 

every home be tested for air tightness. 

The four builders featured in this guide 

each had all of their homes inspected 

and tested for duct tightness and wholehouse air leakage, which puts them ahead 

of the code. In the 2012 IECC, blower door 

and duct blaster testing of every home 

is a requirement. 

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CHAPTER 11. INSPECTING, TESTING, AND COMMISSIONING

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 11.1
and pre-job/post-job checklists filled out by the subcontractor can 

help solve recurring problems. These are both described in Chapter 

12. A checklist for designers in Chapter 13 contains many of the 

provisions that site supervisors should look for and work to include. 

Building Commissioning

Basic commissioning of the house and its mechanical systems is 

vital for high-performance housing and should be completed before 

the home is considered ready for the homeowner to take possession. 

Commissioning activities include verifying the installation and 

operation of HVAC equipment, especially for advanced systems 

like combination water/space heating systems, ground-source heat 

pumps, solar thermal systems, and photovoltaic arrays. Combustion 

safety testing should be conducted if any combustion appliances 

(including fireplaces) are installed. Additional testing recommended 

by Building America includes whole-house air leakage testing with 

a blower door test, duct air tightness testing, and pressure balance 

testing of each room. These activities are described below.

Pre-Dry Wall Inspection and Duct Pressure Testing

[The 2009 IECC 403.2 requires that ducts be tested for air tightness 

and allows for the testing to occur either before or after drywall is 

put up. If tested at pre-drywall or rough-in, duct leakage must be 

≤6 cfm per 100 ft2

 of conditioned floor area at 25 Pa; if tested after 

construction, then ≤8 cfm at 25 Pa. (If the air handler and all ducts 

are in conditioned space, duct leakage testing is not required.) The 

2012 IECC 403.2.2 requires that ducts be tested at rough-in and have 

total leakage that is ≤4 cfm/100 ft2

 of conditioned floor area at 

25 Pascals including the air handler enclosure, or ≤3 cfm/100 ft2

 of 

conditioned floor area at 25 Pa if the air handler is not installed at 

the time of the test. If the duct leakage is tested after construction is 

complete, total leakage must be ≤4 cfm/100 ft2

 at 25 Pa. Duct leakage 

testing is not required if the ducts and air handler are located 

entirely within the building thermal envelope.] 

Building America recommends performing a duct pressure test 

(“duct blaster” test) before drywalling, with the HVAC contractor 

present. If the ductwork fails to meet the pressure criteria, a smoke 

test will reveal the worst leaks and they can be sealed while they are 

still accessible. The HVAC contractor should also test the HVAC 

system to ensure that thermostats and any zone dampers are 

operating correctly and that bypass dampers are properly adjusted. 

The pre-drywall inspection is also a good time to visually inspect 

that insulation and draft-stopping have been properly installed.

“Monitoring progress is the 

only way you are going to 

change behavior.” 

Nat Hodgson, vice president of construction, 

Pulte Homes Las Vegas Division

Before the drywalling starts, you should 

conduct a pre-drywall inspection to 

test ducts and make sure insulation is 

properly installed and test moisture 

levels in framing.

CHAPTER 11 / BUILDING AMERICA BEST PRACTICES SERIES

11.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Whole-House Pressure Testing and HERS Rating 

After completion of the home, including all interior and exterior 

finishes but before occupancy, whole-house air tightness is tested.

[The 2009 IECC 402.4.2 gives two options for demonstrating building 

air tightness. The home can be blower door tested and must show 

leakage of less than 7 ACH at 50 Pa. Or, the 2009 IECC allows an 

extensive visual inspection of all of the areas listed in the 2009 IECC 

402.4.2.2. The 2012 IECC R402.4.1.2 eliminates the visual inspection 

and requires that all homes be blower door tested. Homes in IECC 

climate zones 1 and 2 must show air leakage rates of ≤5 ACH when 

tested at 50 Pa. Homes in IECC climates zones 3 through 8 must 

show air leakage rates of ≤3 ACH at 50 Pa. The testing may need 

to be conducted by an approved third party, if required by the 

code official.] Building America also recommends a blower door 

test. In addition, at this time, you should verify that all specified 

energy-efficient lighting and appliances were installed and check 

the air-conditioner or heat pump refrigerant charge if your HVAC 

contractor has not already done so.

Duct testing and whole-house pressure tests can be conducted by a 

certified HERS rater. The HERS rater should conduct a combustion 

safety test of all fuel-fired equipment as part of the rating certification. 

The HERS rating itself can be a valuable marketing tool for an 

energy-efficient house. Homes built to the recommendations in this 

guide would achieve a HERS score of 70 or lower. Homes built to 

the 2006 IECC would score 100 on the HERS index.

To identify a certified rater in your area, check the registry at 

the Residential Energy Services Network (RESNET) website: 

www.natresnet.org.

SNAPSHOT Form 

Building Science Corporation developed a commissioning checklist 

called the SNAPSHOT form. This form is shown on the next page 

and is available at www.buildingscience.com/documents/reports/

rr-0413b-snapshot-form/view?topic=doctypes/reports. Also, the 

Air Conditioning Contractors of America (ACCA) has developed 

guidance on commissioning of residential mechanical systems, HVAC 

Quality Installation Specification, ANSI/ACCA 5 QI-2010, which is 

available at www.acca.org/industry/quality/quality-installation. 

Homeowner Education

Homeowners should also be given 

information on maintenance and operation 

of the HVAC equipment in their new 

home. Building Science Corporation put 

together a homeowner’s manual for the 

EcoVillage project in Cleveland, Ohio, 

that can serve as a sample for builders 

wishing to create a homeowner’s manual 

for their developments. The manual can be 

downloaded at www.buildingscience.com/

documents/reports/rr-0310-ecovillagehomeowner-handbook.

For More Information

ACCA. 2010. ANSI/ACCA Standard #5 

HVAC Quality installation Specification, 

Air Conditioning Contractors of America, 

Arlington, Virginia, www.acca.org/industry/

quality/quality-installation

Building Science Corporation. 2004. The 

“SNAPSHOT”- A Quick Description, Research 

Report 0413a, www.buildingscience.com/

documents/reports/rr-0413-the-snapshot2014aquick-description

Building Science Corporation. 2004. EcoVillage 

Homeowner Handbook, Research Report 0310, 

www.buildingscience.com/documents/reports/rr0310-ecovillage-homeowner-handbook

Building Science Corporation. 2008. Quality 

Assurance Roadmap for High Performance 

Residential Buildings, www.toolbase.org/PDF/

BestPractices/QualityAssuranceRoadmap.pdf

11.3

CHAPTER 11. INSPECTING, TESTING, AND COMMISSIONING

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 11.3
CHAPTER 11 / BUILDING AMERICA BEST PRACTICES SERIES

11.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Getting a high-performance home requires having good plans; the 

proper contracts, permits, and materials; and properly trained and 

competent installers, who are scheduled at the right time and whose 

work is verified with testing. 

Construction and Contract Documents 

Builders should use construction and contract documents 

[in compliance with 2009 IECC 103] including plans and specifications, 

scopes of work, and job-ready and job-complete checklists, to 

describe and define exactly what you want from your subcontractors.

PLANS AND SPECIFICATIONS – Elevations, floor plans, and 

equipment layout should clearly identify all details related to 

energy efficiency, such as duct layout, advanced framing techniques, 

moisture management techniques, and air sealing details. Plans 

and specifications should include sufficient building and equipment 

details for the code inspector [as required by the 2009 IECC 103]. 

SCOPES OF WORK – Scopes of work define expectations and 

explain unfamiliar sequences of work. The Building America research 

teams have put together an extensive set of sample scopes of work 

that builders can include with contract documents, covering the 

foundation, framing, walls/drainage plane, windows, HVAC, and 

air sealing. See Appendix E of Achieving 30% Whole-House Energy 

Savings Level in Marine Climates (DOE 2006).

JOB-READY CHECKLIST – Signed by the site supervisor and trade 

contractor, the job-ready checklist includes all items that must be 

installed or prepared on the job site, by other trade contractors, 

before the contractor’s work can begin.

JOB-COMPLETE CHECKLIST – Signed by the site supervisor 

and trade contractor, it confirms that the contractor’s work was 

completed as specified.

Chapter 12.

Construction Site 

Documents, Scheduling, 

and Training

CHAPTER TOPICS

12.1 Construction and 

Contract Documents

12.3 Scheduling

12.5 Training Installers

“Keys to success are commitment 

from the final decision maker; 

scopes of work for subcontractors 

with specific performance criteria; 

clear communication with the 

trades often accompanied by 

training and education activities; 

independent third party testing, 

commissioning and feedback to 

the builder; ongoing training, and 

marketing...If the above process 

is followed, the results are going 

to be increased sales and profits 

for the home builders, satisfied 

homeowners and significant 

energy savings with its attendant 

economic and environmental 

benefits for all.”

Ken Fonorow, Florida HERO, 

a Building America research partner

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Site supervisors should review construction documents before 

they are folded into contracts and should continue to provide 

recommendations as these documents are put into practice to 

make them as effective as possible. The popular management term 

for ongoing feedback and dialogue is “continuous improvement,” 

a term coined by W. Edwards Deming. The point here is that when 

workers in the field find ways to improve designs or construction 

processes, that information needs to be communicated back to 

designers and managers so that documentation can capture those 

improvements. Although individual improvements may seem 

small, capturing these in construction documents helps you achieve 

superior building in the field. 

Contract Documents

Clear contract documents make for clear expectations with trade 

contractors. Ensure that trade contracts include the following 

provisions adapted from the NAHB Research Center Toolbase:

•	 Trade contractors are contractually obligated to ensure that 

workers fully understand field specifications and builder quality 

assurance processes using pre-job and post-job checklists.

•	 A competent crew leader will be in charge of all crews and be able 

to communicate with the builder’s site supervisor.

•	 All work must be completed in accordance with field specifications, 

applicable building codes, and industry standards.

•	 Trades must identify recurring errors in their work and train 

crews as needed to reduce similar errors (see HotSpots example 

at the end of this chapter).

(left) Use plans to spell out details that 

will ensure energy efficiency and durability 

like framing techniques, duct layouts, 

housewrap, flashing, and air sealing.

(right) Hold a pre-construction meeting 

with all subcontractors present to talk 

about the schedule and trade interactions, 

especially any changes from the typical 

routine to accommodate new methods 

or technologies.

“We have every trade fill out jobready and job-complete forms. We 

want to know what was ready and 

what wasn’t when they showed up 

at their job. Those delays frustrate 

them and cost us money.”

Vern McKown, co-owner of Ideal Homes, 

in Norman, Oklahoma, shared these tips at 

the EEBA National Conference in Denver, 

Colorado, September 2009

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12.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
•	 Trades must self-inspect each phase of work before reporting the 

work complete to the site supervisor. Trades will confirm in writing 

that all materials and equipment were installed according to field 

specifications and manufacturers’ instructions, using pre-job and 

post-job checklists. 

•	 Copies of both field specifications and the manufacturers’ 

instructions should be available on the job site.

Change Orders

Change orders occur when changes have to be made to the 

original plans, because of a change in equipment or materials, or 

because a design change was made, or because the original plans 

didn’t provide correct details. Change orders and their impacts 

on building performance can be minimized by providing detailed 

plans including a site plan, assembly sequence drawings, framing 

layout with mechanical layout, and mechanical system equipment 

and distribution layout. Equipment schedules can be integrated 

into these plans. The detailed drawings should address structural 

connections (load transfer paths), movements and tolerances, and 

continuity of water, air, vapor, and heat control layers. With these 

drawings it is important to convey both the sequence of each step 

and the intent of these steps to achieve high performance. The plans 

should be reviewed by the architect to make sure they are complete. 

The builder’s team (including the site supervisor and subcontractors) 

should review the plans together before construction starts so the 

builder can convey the design intent, proposed methods, and required 

performance level. These quality control steps will greatly minimize 

change orders and, if changes do need to be made, all team members 

will have a clear understanding of what is being changed (Lukachko 

et al. 2011).

Scheduling

Building an energy-efficient home requires careful attention to 

scheduling. Several new construction techniques require changing 

the order of subcontractors or a shifting of responsibilities, and 

some new activities will need to be added into the schedule. Here 

are some important schedule considerations:

•	 Schedule HVAC rough-in before plumbing and electrical. It is far 

more important for the ductwork to have unconstricted access and 

pathways than it is for wires or pipes. However, be sure needs for 

other systems, such as drain pitch, are coordinated.

“It took us awhile to get to where 

we could build our homes as 

tightly as we needed to, to train 

our air conditioning contractors 

to where their duct work was as 

tight as it needed to be, and our 

insulation contractors to air seal 

in the way they needed to. This 

[energy-efficient building] isn’t 

something that a builder can 

do just by flipping a switch or 

spending more money. You have 

to fail a lot of blower door tests 

and duct blaster tests first.”

David Weekley, president, 

David Weekley Homes

For More Information on 

Construction and Contract 

Documents

DOE. 2006. Achieving 30% Whole-House Energy 

Savings Level in Marine Climates. Prepared 

for the U.S. Department of Energy by the 

Building America Research Teams (BAIHP, 

BIRA, BSC, CARB, DEG, IBACOS, NAHBRC, and 

NREL), http://apps1.eere.energy.gov/buildings/

publications/pdfs/building_america/39743.pdf.

Lukachko, Gates, and Straube. 2011. 3.1.1 

Construction Documents for High-Performance 

Homes, Building Science Corporation, 

www.BuildingAmerica.gov

NAHBRC. 2006. “Quality Matters: Six Ways 

to Improve Trade Contracts.” ToolBase News, 

Summer 2006: Volume 11, Issue 3.

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•	 If using an insulated, conditioned attic, schedule insulating under 

the roof deck before HVAC is installed. The insulators must be able 

to do their job without tromping on the carefully placed ductwork.

•	 Be sure to schedule caulking of electrical and plumbing 

penetrations before the drywall is completed and after the lines 

have been installed.

•	 Don’t forget to schedule for pipe insulation under the slab.

•	 Be sure to schedule pre-drywall insulation inspections, flashing 

inspections, and envelope and duct pressure tests. Inspect at key 

points to ensure that insulation and envelope sealing take place 

before areas become inaccessible. Inspections are much more likely 

to happen if scheduled, and subcontractors may be a bit more 

conscientious if they know their work will be evaluated. 

•	 If ducts are installed in conditioned space, drywall must be 

installed behind duct chases and soffits before they are framed.

Some situations that may require a shifting of responsibilities 

include the following:

•	 If using advanced framing techniques that include two-stud 

corners and floating drywall corners, someone must attach drywall 

clips. The framer is a more likely candidate than the drywall 

installer for framing modifications.

•	 Some caulking work needs to be done by the HVAC subcontractor. 

In particular, the main supply and return trunks that lead through 

the walls need to be caulked by the person connecting them to the 

equipment. Don’t let the drywall finisher do this with mud—it is 

neither a good sealant nor durable enough. Also, all duct terminations, 

including jump ducts, must be sealed when registers are installed.

•	 Some post-finish caulking can be avoided by having the electrician 

use pre-fabricated airtight electrical boxes. 

•	 If installations of windows and drainage planes are done by 

different subcontractors, the window installer must be careful 

to leave flashing unattached at the bottom so that the first row 

of building paper may be tucked under it (see Chapter 14 for an 

installer’s guide to window flashing, housewrap, and sealants).

•	 If you are using insulated headers, the framer will need to install 

insulation inside any double headers (using foam insulation). Open 

headers may be left for the insulation contractor. Pre-fabricated, 

insulated headers are another alternative.

“You can expect what 

you inspect.”

Dr. W. Edwards Deming, the originator 

of total quality management

Make your expectations clear with onsite 

meetings and visible inspection checklists.

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12.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
•	 Draftstops must be installed behind bathtubs and stairwells on 

exterior framed walls. The framer or insulator should do this, 

but be sure that insulation is installed before the draftstopping 

material. The plumber can be asked to install the draftstopping 

and insulation.

Efficient scheduling of subcontractors can bring huge rewards in 

reduced costs and improved quality.

Training Installers 

High-performance home construction does not just happen. Training 

is essential. Training need not involve days off the work site sitting 

in big lecture halls. Hands-on training is the most common approach 

and can happen constantly. Here are some ideas for training:

•	 Schedule a pre-construction meeting with all of your subcontractors 

present to review required interactions between trades.

•	 Meet with your subcontractors at the job site to explain how to 

use new techniques and materials. 

•	 Provide your contractors with manufacturers’ installation 

instructions and material data sheets and go through those 

instructions together. Other installation guides you may want to 

share with subcontractors include the field guides for installers 

shown in Chapter 14 of this guide, or the DOE Building Energy 

Code Program’s Code Notes (see examples in Appendix 2).

•	 Encourage in-house staff and regular subcontractors to take 

advantage of web-based videos, online training, and classroom 

training at community colleges during the off season.

Training Tips from Mixed-Humid Climate Builders

All of the builders who work with Building America mention the 

importance of training to meet their energy efficiency goals. 

Urbane Homes holds pre-construction meetings so the site 

superintendent can coordinate schedules with the trade contractors. 

Urbane provides training sessions for their subcontractors on the use 

of newer products like exterior rigid foam and they have developed 

a framing manual for the special techniques they expect their 

framers to use. David Weekley Homes’ Houston division employs a 

full-time quality coach. Building America research partner Building 

Science Corporation worked with the coach to train several groups 

of Weekley employees, including site supervisors, sales agents, and 

Training on the job site can include 

reviewing manufacturers’ installation 

instructions, going through job-ready 

and job-complete checklists, and using 

HotSpot forms.

“We hold meetings with our trade 

contractor steering committee. 

We ask our employees and our 

subs, what can we do better? The 

construction supervisor walks 

the sites to identify any recurring 

issues. And we do NAHB quality 

certification audits of the whole 

company on a regular basis.”

Vern McKown, co-owner of Ideal Homes, 

in Norman, Oklahoma, shared these tips at 

the EEBA National Conference in Denver, 

Colorado, September 2009.

“Our framers do the majority of 

our air sealing, so when we make 

changes to our process, they get 

an updated manual and do a great 

job with it.”

Abe Gilbert, co-owner, Urbane Homes, 

Louisville, Kentucky

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subcontractors involved in advanced framing, enclosure air sealing, 

duct sealing, and HVAC system sizing. Building Science Corporation 

noted that one of the most difficult things to train was the advanced 

framing techniques. They repeatedly pointed out unnecessary 

framing pieces to contractors, only to see them installed on the next 

home. When site supervisors began making the contractors go back 

and remove extra pieces of lumber, then the contractors started 

consistently using the advanced framing techniques. David Weekley 

Homes was so pleased with the advanced framing they implemented 

it in other divisions as well. 

Building America’s team lead IBACOS took an active role in 

subcontractor training on a Building America project in Pittsburgh. 

IBACOS prepared mockups of field assemblies at its warehouse and 

provided hands-on training sessions. “We had the actual crew who 

would be performing the work in the field practice by working on 

the mockups. If they had any questions or suggestions for improving 

the process, we could work this out before we got into the field,” said 

Kevin Brozyna, an IBACOS building performance specialist.

Training Opportunities

Building America’s research partners represent some of the world’s 

leading building scientists. In addition to providing training to the 

builders with whom they work, Building America research partners 

provide training and national certifications to builders and contractors 

across the country. For a current list of research partners and links, 

see the Building America website, www.eere.energy.gov/buildings/

building_america/research_teams.html.

HotSpot Inspections and Training 

Systematically checking work is an important aspect of quality 

construction. The NAHB Research Center developed the concept 

of HotSpot Inspections and Training to correct recurring 

problems. Builders can use “HotSpot” forms like the sample on the 

following page to note problem areas that need to be inspected and 

signed off by the site supervisor.

Cooling the HotSpots

The NAHB Research Center 

recommends using HotSpots 

inspection forms. HotSpot inspection 

forms are used by supervisors 

on every job:

•	 Distribute and discuss HotSpot 

inspection forms in weekly 

production meetings.

•	 Identify quality issues through 

job inspections, builder feedback, 

and comprehensive quality reviews. 

Include the problems that show 

up often on your punch lists.

•	 Add HotSpot checkpoints to 

the inspection form where 

improvement is needed.

•	 Train site supervisors in procedures 

to prevent identified problems. 

•	 Develop one-page diagrams that 

address specific problem areas 

and use these in toolbox talks to 

train crews.

•	 Monitor the use of the new 

processes and the quality of 

installations. Results provide 

feedback on the effectiveness 

of the improvements.

•	 Celebrate success. When a 

HotSpot is no longer an issue, 

remove it from the HotSpot list 

and put it in a reminder section. 

In time, items may leave the 

inspection form altogether.

Adapted from the ToolBase Resources 

Website at www.toolbase.org/BestPractices/Business-Management/HotSpot-Inspections. This website includes 

examples of HotSpot inspection forms.

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CHAPTER 12 / BUILDING AMERICA BEST PRACTICES SERIES

12.8 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
This checklist summarizes the measures presented in Chapters 6–12. 

Measures from the ENERGY STAR Qualified Homes, Version 

3 (Rev 4.0) National Program Requirements are included as well; 

see the Requirements document for more specific details (www.

energystar.gov/ia/partners/bldrs_lenders_raters/ES_Combined_

Path_v65_clean_508.pdf). The 2009 and 2012 IECC and IRC 

code requirements for the measures listed below can be found with 

descriptions of these measures in Chapters 6 through 12 of this guide. 

Designers, use this checklist as a reminder to investigate these 

measures throughout the design process. It is important to develop 

specifications and drawings to ensure that selected features are 

included in construction documents. 

Site supervisors, use this list to develop customized onsite pre-job 

and post-job inspection checklists for each trade contractor.

Chapter 13.

Durability and EnergyEfficiency Checklist

CHAPTER TOPICS

13.1 Foundation Assemblies

13.5 Wall Assemblies

13.7 Roof Assemblies

13.8 Whole-House Air Leakage

13.8 Mechanical Systems

13.11 Commissioning

Foundation Assemblies

Slabs, crawlspaces, and piers are all common foundation types in 

the mixed-humid climate. The checklists below address control of 

moisture, airflow, and heat flow in each foundation type.

Controlling Moisture in All Foundation Types

 Maintain a surface grade of at least a 1/2 inch per foot for 

at least 10 feet around and away from the entire structure.

 Slope impervious surfaces such as driveways, garage slabs, 

patios, stoops, and walkways away from the structure at 

least 1/4-inch per foot to edge of surface or 10 feet, 

whichever is less. 

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CHAPTER 13. CHECKLIST

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 Design the house structure with overhangs, gutters, drainage planes, and flashing to shed rainwater and 

conduct it away from the house.

 Slope top soil to drain away from the house. Building America recommends a surface grade of 

at least 5% for at least 10 feet around and away from the entire structure.

 Keep all untreated wood away from contact with earth and concrete. Keep wood and fiber cement siding 

at least 8 inches from the soil surface to minimize damage from rain splashing up from ground surface.

 Install a protective shield such as a plastic L bracket, gasket, or water-proof membrane between 

foundation wall stem and sill plate to keep capillary water from wicking into the wall from the foundation. 

Metal flashing can also serve this function and serve as a termite shield.

 Specify and show in details that 6-mil polyethylene sheeting or rigid foam insulation is to be placed 

directly beneath the slab or basement floor. The sheeting should continuously wrap the slab as well as 

footings up to grade. 

 Damp proof all below-grade portions of the exterior foundation. Damp proof the exposed portion of 

the foundation with latex paint or other sealant. 

 Specify that footings poured independent of slabs or foundation walls are to be treated with a 

bituminous damp-proof coating of masonry capillary-break paint, or a layer of 6-mil polyethylene 

plastic to isolate the footing from the remainder of the assembly.

 Ensure that the lowest excavated site foundation level is above the local groundwater table at its 

maximum elevation. 

 Place a 4-inch-deep, 3⁄4-inch gravel bed directly beneath the polyethylene sheeting to act as a capillary 

break and drainage pad. 

 Do not place a sand layer between the vapor retarder and the concrete slab or basement floor. 

Differential drying and cracking is better handled with a low water-to-concrete ratio and wetted 

burlap covering during initial curing.

 In flood-prone areas, build homes on piers with floors one foot above the base flood elevation.

 Ensure sump pump cover is mechanically attached and has a full gasket seal or equivalent. 

 In all crawlspaces, install 6-mil polyethylene across the entire ground surface. Overlay all seams 

by 12 inches and tape. Seal the polyethylene at least 6 inches up the walls or to a height equal to 

ground level.

 Install a perimeter drain below the drainage plane along (not on top of) footings for all basements 

and crawlspaces where the floor is below grade (use perforated PVC pipe covered with gravel, 

landscape fabric, and backfill).

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13.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Controlling Heat Flow in Slab Foundations

 Follow local code requirements regarding termite inspection of foundation walls.

 Slabs may be insulated at the perimeter with borate-treated foam board or rigid fiberglass insulation. 

Use only insulation approved for below-grade use. 

 Exterior insulation should be applied from the top of the foundation wall to the bottom of the frost line. 

Cover the exterior face of the insulation exposed to outside air using flashing, fiber cement board, parging, 

treated plywood, or membrane material. 

Controlling Heat Flow in Crawlspace Foundations

 Follow local code requirements regarding termite inspection of foundation walls.

 The preferred approach is to install insulation on the exterior side of the foundation wall. Products such as 

borate-treated foam board or rigid fiberglass insulation work well. Insulate the exterior side of the beam to R-5.6.

 Insulation that is exposed above grade must be covered with a protective coating such as flashing, fiber 

cement board, parging, treated plywood, or membrane material.

 If insulation is placed on the interior, it must extend down the wall to a depth at least 2 feet below grade 

level and be rated for crawlspace and basement exposure.

 If the floor is insulated instead, insulate to R-30 in IECC climate zones 5 and 6, R-38 in climate zones 7 

and 8 (or sufficient to fill the framing cavity, at least R-19).

Controlling Heat Flow in Basement Foundations

 Follow local code requirements regarding termite inspection of foundation walls.

 Wall insulating in basements is similar to the approaches described for crawlspaces. Basement floors are 

insulated similarly to slabs.

 Exterior wall insulation is preferable in basement foundation applications.

 Material in contact with the foundation wall and the concrete slab must be moisture tolerant. A capillary 

break must be placed between materials that transport moisture and moisture-sensitive materials.

 Interior insulation, if used, should employ one of the following methods:

 Use foil-faced polyisocyanurate rigid insulation attached directly to the above-grade portion of the wall. 

Extruded or expanded polystyrene can be attached to the below-grade portion of the wall. The polystyrene 

would require a gypsum board or equivalent covering. Foam sill seal or foam board can be used between the 

bottom plate of the wall and the concrete floor to provide a capillary break.

 Use either expanded or extruded polystyrene foam board attached to the entire foundation wall. Additional 

insulation can be added to a frame wall built on the interior of the foam insulation. If no frame wall with 

additional insulation is added, wood furring strips can be attached over the foam and gypsum board 

attached to the furring strips.

 Use pre-cast concrete foundation walls that come with a minimum of 1 inch of rigid foam insulation 

attached to the interior.

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CHAPTER 13. CHECKLIST

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 13.3
Controlling Air Infiltration in All Foundation Types

 Install a sill gasket between the foundation and the bottom plate of the exterior framed wall to 

prevent air leaks and serve as a capillary break.

 Seal all panel joints to stop air leakage through subfloor sheathing installed over unconditioned 

spaces such as vented crawlspaces, unconditioned garages, or cantilevered floors over exterior walls.

 Use caulk, spray foam, and blocking material to air seal all penetrations through the sill plate and 

subfloor for plumbing, wiring, and ducts.

 Weatherstrip basement and crawlspace doors and access hatches.

Other Foundation Issues

RADON CONTROL

 Use a layer of gravel under the slab to provide a path for radon and other soil gas to escape to 

the atmosphere rather than being drawn into the house. 

 Use a vapor retarder to block soil gas entry into the house. 

 See EPA website: www.epa.gov/iaq/whereyoulive.html for information about local variations in 

radon levels.

 Include a sub-slab-to-roof vent system to vent radon and soil gases.

 Install a fan on the vent stack if testing of the house shows high radon levels.

PEST CONTROL 

 Use termite treatments, bait systems, and treated building materials for assemblies that are near soil or 

have ground contact.

 Provide roof drainage to carry water at least 3 feet away from the building.

 Apply decorative ground cover no more than 2 inches deep within 18 inches of the foundation.

 Keep plantings at least 30 inches from the foundation with supporting irrigation directed away 

from the finished structure.

 Install a metal termite shield at the sill plate.

CHAPTER 13 / BUILDING AMERICA BEST PRACTICES SERIES

13.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Wall Assemblies

Controlling Liquid Water in Wall Assemblies

 Install flashing and kickout diverters at all intersections of the wall with roofs and other building elements.

 Install flashing at the bottom of exterior walls with weep holes included for masonry veneer and weep 

screed for stucco cladding systems.

 Properly flash and seal windows, doors, and other penetrations through the wall.

 Specify and show in elevations building paper, housewrap, or taped insulating sheathing (rigid foam 

insulation) behind the exterior cladding to serve as a fully sealed, continuous drainage plane. 

 Provide an air space between the cladding and the drainage plane of 1 to 2 inches for brick and stone 

veneer, 3/4 inch for stucco, and 1/16 inch for lap siding.

 For the drainage plane behind stucco cladding, include two layers of building paper or housewrap to 

avoid chemically contaminating the housewrap.

 If building paper is used as a drainage plane in areas prone to severe storms, use two layers to increase 

resistance to leakage at fasteners and to allow for more flexible installation.

 Overlap housewrap seams shingle style and tape seams. Properly lap at window flashing (over the 

flashing above the windows and to the side, and under the flashing beneath the window).

 Run housewrap top and bottom edges past top and bottom plates by at least one inch and seal at the edges.

 Use overhangs to keep water away from walls and to provide shade.

 In slab foundations, form a stepped-down shelf at the slab edge to seat doors so that any water that gets 

in under them is directed outside.

Controlling Water Vapor in Wall Assemblies

 Back-prime wood and fiber cement cladding to avoid water saturation and migration.

 Do not install vapor barrier (e.g., polyethylene sheeting, foil-faced batt insulation, reflective 

radiant-barrier foil insulation) on the interior side of walls in air-conditioned structures. Wall 

assemblies should be able to dry to at least one side and in many cases both sides of the assembly.

 Do not use impermeable coverings, such as vinyl wallpaper, on exterior walls.

 Use a Class 3 vapor retarder (latex paint) on interior side of walls with vented cladding over 

wall sheathing.

 Leave a drainage space of at least 1/16-inch behind lap siding and 3⁄4 inch between stucco and plastic 

housewraps to control liquid phase water penetration. A 1- to 2-inch air gap is needed behind 

brick veneer.

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CHAPTER 13. CHECKLIST

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 13.5
 Use a non-paper-faced backerboard such as cement board on walls behind tub and shower enclosures 

that are composed of tile or panel assemblies with caulked joints. 

 Do not use building materials that show signs of water damage or mold. 

 Use dry lumber that has a moisture content <18%.

 Follow manufacturers’ drying recommendations for wet-applied insulation.

Controlling Air Infiltration in Wall Assemblies

 Install insulation and an air barrier that is in full contact with the insulation at all exterior walls, and 

behind showers and bathtubs, behind fireplaces, at attic kneewalls and skylight shaft walls, at walls 

adjoining porch roofs, at staircase walls, at double walls, and at garage rim or band joists adjoining 

conditioned space.

 Use interior gypsum board as the interior air infiltration barrier. Tape and mud gypsum board at 

all joints and the intersections of the wall with the floor and the ceiling.

 Create an exterior air infiltration barrier using taped and sealed exterior rigid foam insulating 

sheathing to control wind washing and to keep air from entering the wall from the exterior. 

 Use the ENERGY STAR Thermal Enclosure System Rater Checklist (ENERGY STAR Qualified 

Homes, Version 3).

 Seal all exterior wall penetrations (exterior lights, phone lines, vents, faucet pipes, cables, etc...) 

with caulk, gaskets, or other sealants.

 For occupant health and safety, verify air sealing at all shared walls and ceilings between attached 

garages and living spaces. 

Controlling Heat Flow in Wall Assemblies

 Reduce thermal bridging at exterior walls by insulating with rigid insulation, insulated siding, 

structural insulated panels, or insulated concrete forms. 

 If using stud-framed walls, use advanced framing techniques to maximize insulation.

 Meet or exceed 2009 IECC insulation requirements.

 Properly install wall insulation to ensure the cavity is completely free of voids.

 Use spray foam to insulate and seal rim joists (and where the wall connects to the roof in non-vented attics).

 Install ENERGY STAR-labeled doors and windows that meet ENERGY STAR requirements for the 

mixed-humid climate. 

 Use roof overhangs, porches, and awnings to provide shade and protect windows, doors, and walls. 

Plant trees to provide shade.

CHAPTER 13 / BUILDING AMERICA BEST PRACTICES SERIES

13.6 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Roof Assemblies 

Controlling Liquid Water in Roof/Attic Assemblies

 In areas with potentially high winds and heavy rains, apply 4-inch to 6-inch “peel and seal” self-adhering 

water-proofing strips over joints in roof decking before installing the roof underlayment and cover.

 Install roofing materials shingle-fashion to provide a continuous drainage plane over the entire surface 

of the roof.

 Properly flash roof valleys and edges and use step and kick-out flashing where roof edges abut walls. 

 Install self-sealing bituminous membrane or equivalent at all valleys and roof deck penetrations.

 Size gutters and downspouts to accommodate anticipated storms. Roof drainage should carry water at 

least 3 feet from the building.

Controlling Water Vapor in Roof/Attic Assemblies

 Install roof, ridge, and soffit ventilation in vented attics.

 Do not use any kind of interior vapor barrier material in the ceiling (e.g., polyethylene sheeting).

Controlling Air Flow in Roof/Attic Assemblies

 Tape and seal all ceiling gypsum board seams so that the gypsum board functions as an air barrier. Ensure 

an air seal at the intersection between the walls and ceilings in attics, cathedral ceilings, and knee walls. 

 Use spray foam for tight sealing of the wall-roof intersection in non-vented attics. 

 Caulk all intersections of ceiling with other components (soffits, ceiling fans, duct registers, light fixtures, etc.). 

 Use draftstopping in dropped ceiling areas.

 Use ceiling light fixtures that are rated for insulation contact and airtight (ICAT); 

install with proper trim and caulk cracks around light fixtures.

 Air seal all penetrations through top plates.

 Weatherstrip and insulate attic access hatches or doors.

 Seal all penetrations through the ceiling and the roof, including holes for flue stacks, wiring, fans, etc.

Controlling Heat Flow in Roof/Attic Assemblies

 Consider a non-vented attic.

 Install insulation amounts that meet or exceed the requirements of the 2009 IECC. 

 Use insulation contact rated recessed can lights and insulate over them.

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CHAPTER 13. CHECKLIST

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 13.7
 Use raised-heel energy trusses to maintain the thickness of ceiling insulation directly above the top 

plates of the exterior wall framing. Maintain the ceiling insulation level throughout the entire plane of 

the ceiling and over the top of the perimeter walls. A depth gauge should be visible from the attic hatch.

 Construct insulation dams around chimneys and flues to allow full attic insulation depth around them.

 Insulate attic doors and hatches. Provide insulation dams around horizontal access doors to allow full 

depth attic insulation. 

 Insulate kneewalls and walls adjoining porch ceilings.

 In vented attics, install baffles to prevent blocking of soffit vents and wind washing.

Whole-House Air Leakage 

 Have building envelope tested for air leakage by a HERS rater who uses a blower door test to confirm 

leakage rates do not exceed code maximums.

Mechanical Systems 

Heating and Cooling Equipment 

 Size heating and cooling equipment using ACCA Manuals J and S.

 Specify central air conditioners at a minimum 13 SEER (10 EER) for cooling, and specify heat 

pumps at a minimum of 7.7 HSPF for heating.

 Install ENERGY STAR-qualified equipment.

 If installing a gas furnace, install a sealed-combustion, condensing furnace that exceeds 90 AFUE and 

install it in conditioned space if possible.

 Isolate HVAC system and ducts from areas with potential pollutants including garage spaces.

 Have the refrigerant charge on the air conditioner or heat pump verified in writing by the installer to be 

within design specifications, using the superheat method for non-Thermostatic Expansion Valve (TXV) 

systems or the subcooling method for TXV systems. 

 Filter HVAC return air through a 4-inch standard filter or a Minimum Efficiency Reporting Values 

(MERV) 8 normal-thickness filter. Make the filter easy to access for cleaning or replacement and 

design the filter slot so there is no air bypass around the filter when the HVAC system is operating. The 

maximum air velocity through the filter should not exceed 400 fpm.

 Keep air pressurization balanced from room to room by providing individual ducted returns for each 

room or by providing jump ducts or transfer grilles located in the walls of each room. Use flex duct 

and staggered grille locations or ducts lined with sound-absorbent material to minimize sound transfer 

through jump ducts.

 Consider alternative energy-efficient equipment such as high-efficiency ductless heat pumps.

CHAPTER 13 / BUILDING AMERICA BEST PRACTICES SERIES

13.8 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Ducts

 Specify location, size, and type of ducts and registers on construction plans. Include heating and cooling 

ducts, passive return air ducts or transfers, location of the mechanical ventilation air inlet, and the 

locations of all exhaust outlets. Indicate the location of dedicated chases for ductwork.

 Place ducts and air handlers in conditioned space when possible. 

 Size ducts using ACCA Manual D. 

 Keep duct runs as short as possible. Consider using a central duct chase in a dropped hallway ceiling 

with registers located along it providing air directly to rooms along the hallway.

 Use ducts made of galvanized sheet metal, duct board, or flex duct, not building cavities.

 Air seal insulated ducts running outside conditioned spaces, by use of proper duct-sealing techniques. 

Use these duct-sealing materials:

 For metal ducts: UL 181 mastic.

 For duct board: UL 181 tapes. 

 For flex duct: a combination of UL 181 mastic and strap ties. 

 Seal drywall connections to ducts with caulk or foam sealant.

 Insulate ducts in unconditioned spaces. Insulate supply ducts to R-8 minimum and return 

ducts to R-4 minimum.

 Insulate ducts in conditioned space to R-8 for supply and R-4 for return ducts to avoid 

condensation formation.

 Equip each bedroom with a separate return duct, transfer grille, or jump duct.

 Don’t use “pan ducts” (spaces between joists and in stud cavities) as supply or return air ducts.

 Don’t locate ducts in exterior walls.

 Seal any return-air ductwork or air handler located in the garage with UL 181-approved mastic.

 Don’t put the air handler in the garage unless it is in an air-sealed, insulated closet. Ducts located in the 

garage may not have any openings in the garage and furnaces and air handlers that supply air to living 

spaces shall not supply air to or return air from a garage. The air handler and any return-air ductwork 

should be thoroughly sealed with UL 181B-M-compliant mastic, with a target leakage between the duct 

system and the garage of 0 CFM @ 25 Pa.

 Verify duct air tightness with a duct blaster pressure test. Test at rough-in when leaks can be easily accessed 

and sealed.

13.9

CHAPTER 13. CHECKLIST

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 13.9
Ventilation

 Provide a fresh-air intake ducted to the return air side of the air handler to provide fresh air and 

air pressure balancing for homes ventilated primarily with exhaust-only kitchen and bath fans.

 Filter ventilation air through a 4-inch standard filter or a new MERV 8 normal-thickness filter. 

Make the filter easy to access for cleaning or replacement and design the filter slot so there is no air 

bypass around the filter when the HVAC system is operating.

 Install ENERGY STAR-qualified low-sone exhaust fans in bathrooms and kitchens. Sone ratings 

should not exceed 1.5. 

 Seal bathroom and kitchen fans to drywall with caulk or gaskets.

 Equip outdoor air intakes and exhausts with automatic or gravity dampers that close when the 

ventilation system is not in operation.

 Consider installing a night ventilation cooling system in appropriate subclimates.

Plumbing

 Locate bathrooms and other hot water-consuming activities near each other in house layout. 

 Centrally locate the water heater to minimize piping trunk lengths. 

 Bury plumbing in attic insulation for single-story, slab-on-grade homes and in interstitial space 

between floors for multi-story homes.

 Install code-permitted or manufacturer-approved minimum size lines.

 Insulate hot water supply lines to R-4.

 Insulate tanks to at least R-12.

 Use a central manifold (home-run) water distribution system.

 Use PEX (high-density polyethylene) piping. Use approved connectors so PEX pipes are not connected 

directly to water heaters or solar collectors.

 Do not install continuous recirculation pumping systems on hot water lines. Use an on-demand switch 

if recirculation controls are desired to minimize the energy penalty of a circulation system.

 If gas water heaters, use closed-combustion or power-vented models.

 Consider alternative technologies like on-demand gas or electric water heaters, solar thermal water 

heaters, and air-source heat pumps for water heating. 

 Use solar water heaters for pools and spas; use high-efficiency pool pumps.

CHAPTER 13 / BUILDING AMERICA BEST PRACTICES SERIES

13.10 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Electrical

 Use ENERGY STAR-qualified compact fluorescent lights (CFLs or LEDs) in all fixtures expected 

to be on more than 2 hours per day.

 Use recessed ceiling lights that are ICAT rated (approved for insulation contact and airtight).

 Use occupant sensors, photocells, and motion sensors to automate lighting operation.

 Use air-sealed electrical boxes in all exterior walls and ceilings adjacent to unconditioned attics.

 Use ENERGY STAR-qualified appliances.

Occupant Health and Safety

 Use only sealed combustion or power-vented combustion appliances in conditioned space.

 Direct vent gas cooking ranges to the outside.

 Use sealed-combustion gas fireplaces to eliminate the threat of harmful combustion gases entering the house. 

 Install CO detectors and smoke alarms.

 Use filtration systems for forced air systems that provide a minimum atmospheric dust spot efficiency of 

30% or MERV 8 or higher.

 Maintain indoor humidity in the range of 30% to 60% by controlled mechanical ventilation, mechanical 

cooling, or dehumidification. 

 Maximize hard surface areas (tile, vinyl, hardwood) to enable homeowners to better manage dust 

for health purposes. For slab-on-grade houses, this also reduces cooling loads.

 Provide occupants with information about the operation and maintenance of the 

building systems that provide space conditioning, hot water, and lighting.

 Ventilate attached garages with a 100 cfm (ducted) or 80 cfm (un-ducted) exhaust fan, venting to 

outdoors and designed for continuous operation. Or, install automatic fan controls that activate 

the fan whenever the garage is occupied and for at least 1 hour after the garage is vacated.

 Completely seal the garage from the conditioned areas of the house to keep car exhaust and chemical 

fumes from entering the home.

 Vent clothes dryers and central vacuum cleaners directly outdoors.

 Use low-VOC paints, finishes, varnishes, and adhesives whenever possible.

Commissioning

 Test ducts for air leakage at rough-in.

 Test whole-house air leakage with a blower door. 

 Do combustion safety testing if combustion appliances are installed in the home.

 Provide homeowners with operation and maintenance guidance to HVAC and mechanical systems.

13.11

CHAPTER 13. CHECKLIST

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 13.11
CHAPTER 13 / BUILDING AMERICA BEST PRACTICES SERIES

13.12 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Chapter 14.

Field Guides 

for Installers

On the following pages you will find step-by-step, easy-to-follow 

illustrated instructions for implementing key energy-efficiency 

technologies.

These guides are designed to be easily duplicated and distributed. 

Hand them to your subcontractors when you meet with them at the 

job site, to help them understand what you expect.

•	 Advanced Framing

•	 Foundation System Insulation, Moisture, and Air Leakage Control

•	 Masonry Construction

•	 Housewrap

•	 Window Flashing

•	 Wall-to-Roof Flashing

•	 Interior Air Sealing

•	 Exterior Air Sealing with Insulating Sheathing Panels

•	 Plumbing Air Sealing

•	 Electrical Air Sealing

•	 Installing Fiberglass Batt Insulation

•	 Installing Windows in Walls with External Rigid Foam Insulation

•	 Duct Location

•	 Air Handler and Duct Sealing 

•	 Ductless Heat Pump Installers Guide 

(from Northwest Energy Efficiency Alliance www.ductless.com)

•	 Roof Fascia/Soffit Vent Detail

•	 Ice Dam Prevention

14.1

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.1
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CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Advanced Framing

The following tips show examples of framing techniques that can create more open space to hold 

insulation while reducing framing costs and waste. The following page shows an example of a 

detailed framing plan. Such detailed plans should be included in construction documents.

Size headers for actual 

loading conditions: 

Non-load-bearing walls 

do not need structural 

headers. Proper 

sizing may allow for the 

use of insulated headers 

in which foam 

insulation is 

sandwiched 

between 

sheathing.

Use two-stud corners:

Rather than using a third 

stud as a nailing edge for 

interior gypsum board, use 

drywall clips, a 1x nailer 

strip, or a recycled plastic 

nailing strip. Using drywall 

clips also reduces drywall 

cracking and nail popping.

Eliminate redundant floor 

joists: Double floor joists 

aren’t needed below nonload-bearing partitions. 

Partitions parallel to 

overhead floor or roof 

framing can be attached to 

2x3 or 2x4 blocking. Nailing 

directly to the sub-floor 

provides adequate support.

Use 2x3s for 

partitions:

Interior, non-loadbearing partition 

walls can be framed 

with 2x3s at 24-in. 

on center or 2x4 

“flat studs” at 16-in. 

on center. 

24” 24” 24” 24” 24”

24”

24”

24”

24”

24”

24” 24” 24” 24” 24”

24”

24”

24”

24”

24”

24” 24” 24” 24” 24”

24”

24”

24”

24”

24”

24” 24” 24” 24” 24”

24”

24”

24”

24”

24”

24” 24” 24” 24” 24”

24”

24”

24”

24”

24”

24” 24” 24” 24” 24”

24”

24”

24”

24”

24”

FROM 

ABOVE

Two-Foot Module Design:

Starting with the foundation, the house 

footprint should be based on 2-foot 

increments. Layouts should be based on 

this 2-foot grid to minimize material waste.

Frame 24-in. on center:

24-in. on center studs are structurally 

adequate for most residential applications. 

Even when the stud size must be increased 

from 2x4 to 2x6, 24-in. spacing can 

significantly reduce framing lumber needed. 

Ladder-block exterior wall 

intersections: Partitions can be 

nailed either directly to a single 

exterior wall stud or to flat blocks 

inserted between studs.

Align framing members and use a single top 

plate: Plate sections are cleated together using 

metal flat plate connectors. Metal connectors can 

be used at partition wall intersection. Underside 

blocking is another option for single top plate butt 

joints. For multistory homes, this may increase 

the stud size on lower floors to 2x6.

Exterior wall top plate

Interior wall 

top plate

Metal connector plate

14.3

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.3
Detailed Wall Framing Layout

Use detailed layouts like this to make sure studs align from first floor to second floor to roof and design on a 24-inch grid.

Figures courtesy of the 

NAHBRC and prepared 

by Steve Baczek.

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Wall Design for Seismic and Hurricane Regions

This advanced framing wall shear panel for seismic and hurricane regions was designed and tested by Building Science Corporation 

and the U.S. Army Construction Engineering Research Laboratory (CERL) with funding from DOE’s Building America program. The 

panel was designed to provide lateral capacity that is as good as or better than traditional plywood-sheathed shear panels, while not 

interfering with the installation of insulation sheathing directly to the framing members. It has an allowable design capacity of 650 lb/ft 

or 2,600 lb per panel. (Figure Source: Building Science Corporation)

Sources and Additional Information

Building Science Corporation. 2009. Enclosures That Work - Building Profile: Hot-Dry/Mixed-Dry: Sacramento, 2009, 

www.buildingscience.com/documents/profiles/etw-sacramento-profile/#F11

NAHB Research Center. “Advanced Framing Techniques: Optimum Value Engineering (OVE),” Available at www.toolbase.org/Construction-Methods/

Wood-Framing/advance-framing-techniques accessed 6-4-08

14.5

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.5
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CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.6 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Foundation System Insulation, Moisture, and Air Leakage Control

= Sealant or Gasket

Concrete

slab

Seal all slab

penetrations

Concrete footing below frost depth

INTERIOR INSULATION 

FOR FLOATING SLAB

EXTERIOR INSULATION

PACKAGE

Gravel base

(4-6" deep coarse, no fines)

Perforated

drain pipe

Hold drywall 

1/2” above floor

Polyethylene or damp proofing capillary break

Polyethylene vapor diffusion retarder

Perforated drainage 

pipe embedded 

in gravel

Use extruded (R-5 per inch)

or expanded (R-4 per inch)

polystyrene or rigid

fiberglass insulation

Cover insulation 

exposed above grade

(see list on reverse)

Rigid foam insulation

(extends under entire slab

and replaces polyethylene 

vapor retarder)

Radon reduction

3" plastic pipe vent stack

Optional blower

Sill gasket 

membrane

(also serves as 

capillary break)

Metal termite 

flashing

Damp proofing Damp proofing

Roof flashing

SHALLOW FROST-PROTECTED 

FOUNDATION

(get code approval before proceeding)

6 Mil. Polyethylene

vapor diffusion retarder

(extends under grade beam 

acting as a capillary break)

Rigid insulation 

extends horizontally

(horizontal distance 

ilt tft dth)

Rigid insulation 

extends horizontally 2’

Damp proofing

Cover insulation 

exposed above grade

(see list on reverse)

See more information on the following page.

14.7

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.7
Sources & Additional Information

U.S. DOE, Technology Fact Sheet on Slab Insulation.

U.S. EPA, Building Radon Out: A Step-By-Step Guide oni How to Build Radon Resistent Homes.

Southface Energy Institute. 2002. Fact Sheets #29: Insulating Foundation and Doors. www.southface.org/factsheets/29_insulatefloors4PDF.pdf

Southface Energy Institute. 2002. Fact Sheets #30: Radon-Resistant Construction for Builders.

www.southface.org/default-interior/Documents/30_radonresistantconst.pdf

Building Science Consortium. “Profiles: Hot-Humid Climate,” www.buildingscience.com/documents/profiles

•	 Keep all untreated wood materials away 

from contact with earth and concrete. 

•	 Design the house structure with 

overhangs, gutters, drainage planes, 

and flashing to shed rainwater and 

conduct it away from the house.

•	 Slope the earth away from the house 

and ensure that no irrigation strikes 

near the foundation.

•	 Use a sill gasket for air sealing.

•	 Install a protective shield such as 

metal flashing, plastic L bracket, or 

a membrane (such as EPDM flexible 

roofing material*) to block capillary 

water wicking into the wall from the 

foundation. The protective shield may 

also serve as a termite shield.

•	 Slabs require a foundation drain where 

the slab (or floor) is located below 

grade. Install a foundation drain 

alongside the footing (not above it). 

The drain should rest in a bed of coarse 

gravel (no fines) that slopes away from 

the foundation and is covered with 

filter fabric.

•	 Exterior rigid fiberglass insulation 

may provide a drainage plane that will 

channel water to the foundation drain 

and relieve hydrostatic pressure. 

•	 Exterior foundation wall insulation 

requires a protective coating at 

above-grade applications. Examples 

of protective coverings for exterior, 

above-grade insulation include flashing, 

fiber-cement board, parging (stucco 

type material), treated plywood, or 

membrane material (EPDM* flexible roofing). 

•	 Note that some code jurisdictions 

may require a gap between exterior 

insulation and wood foundation 

elements to provide a termite 

inspection area.

•	 Install damp proofing or a polyethylene 

sheet over the footing to block 

capillary water wicking into the 

foundation side wall.

•	 Install a capillary break and vapor 

retarder under the entire slab consisting 

of at least a 6-mil polyethylene sheet 

or continuous rigid foam insulation 

approved for below-grade applications, 

on top of 4 to 6 inches of coarse gravel. 

•	 Install radon control measures 

(check local requirements and EPA 

recommendations).

*EPDM = Ethylene Propylene Diene Monomer. 

Slab Foundation System Insulation, Moisture, and Air Leakage Control

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.8 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Basement & Conditioned Crawlspace Insulation, Moisture, and Air Leakage Control

Sill gasket membrane

(also serves as capillary break)

Metal termite flashing

Concrete footing

below frost depth

Polyethylene or damp

proofing capillary break

Rigid fiberglass insulation

Polyethylene vapor barrier

Damp proofing

Perforated drainage

pipe embedded in

coarse gravel

Treated wood nailer

(bring vapor barrier

up to grade level)

Cavity insulation

= Sealant or Gasket

Cover insulation

exposed above grade

Rigid Insulation

Continuous

polyethylene

Damp proofing

Rigid insulation

Treated

wood nailer

Polyethylene or 

damp proofing 

capillary break

Rigid insulation

Rigid insulation

Damp proofing

Continuous

polyethylene

Polyethylene or 

damp proofing 

capillary break

Sill gasket membrane

(also serves as capillary break)

Metal termite flashing

Concrete footing

below frost depth

Polyethylene or damp

proofing capillary Break

Rigid fiberglass insulation

Polyethylene vapor

diffusion retarder

Damp proofing

Perforated drainage

pipe embedded in

coarse gravel

Radon reduction

3” plastic vent pipe

Cavity insulation

Cover insulation

exposed above grade

Rigid insulation

with foil facing

Damp proofing

Cavity

insulation

Polyethylene or

damp proofing

capillary break

Sill gasket membrane

(also serves as capillary break)

Metal termite flashing

Concrete footing

below frost depth

Polyethylene or damp

proofing capillary break

Rigid fiberglass insulation

Polyethylene vapor barrier

Damp proofing

Perforated drainage

pipe embedded in

coarse gravel

Treated wood nailer

(bring vapor barrier

up to grade level)

Cavity insulation

= Sealant or Gasket

Cover insulation

exposed above grade

Rigid Insulation

Continuous

polyethylene

Damp proofing

Rigid insulation

Treated

wood nailer

Polyethylene or 

damp proofing 

capillary break

Rigid insulation

Rigid insulation

Damp proofing

Continuous

polyethylene

Polyethylene or 

damp proofing 

capillary break

Sill gasket membrane

(also serves as capillary break)

Metal termite flashing

Concrete footing

Polyethylene or damp

proofing capillary Break

Rigid fiberglass insulation

Polyethylene vapor

diffusion retarder

Damp proofing

Perforated drainage

pipe embedded in

coarse gravel

Radon reduction

3” plastic vent pipe

Cavity insulation

Cover insulation

exposed above grade

Rigid insulation

with foil facing

Damp proofing

Cavity

insulation

Polyethylene or

damp proofing

capillary break

Sill gasket membrane

(also serves as capillary break)

Metal termite flashing

Concrete footing

below frost depth

Polyethylene or damp

proofing capillary break

Rigid fiberglass insulation

Polyethylene vapor barrier

Damp proofing

Perforated drainage

pipe embedded in

coarse gravel

Treated wood nailer

(bring vapor barrier

up to grade level)

Cavity insulation

= Sealant or Gasket

Cover insulation

exposed above grade

Rigid Insulation

Continuous

polyethylene

Damp proofing

Rigid insulation

Treated

wood nailer

Polyethylene or 

damp proofing 

capillary break

Rigid insulation

Rigid insulation

Damp proofing

Continuous

polyethylene

Polyethylene or 

damp proofing 

capillary break

Sill gasket membrane

(also serves as capillary break)

Metal termite flashing

Concrete footing

below frost depth

Polyethylene or damp

proofing capillary Break

Rigid fiberglass insulation

Polyethylene vapor

diffusion retarder

Damp proofing

Perforated drainage

pipe embedded in

coarse gravel

Radon reduction

3” plastic vent pipe

Cavity insulation

Cover insulation

exposed above grade

Rigid insulation

with foil facing

Damp proofing

Cavity

insulation

Polyethylene or

damp proofing

capillary break

Sill gasket membrane

(also serves as capillary break)

Metal termite flashing

Concrete footing

below frost depth

Polyethylene or damp

proofing capillary break

Rigid fiberglass insulation

Polyethylene vapor barrier

Damp proofing

Perforated drainage

pipe embedded in

coarse gravel

Treated wood nailer

(bring vapor barrier

up to grade level)

Cavity insulation

= Sealant or Gasket

Cover insulation

exposed above grade

Rigid Insulation

Continuous

polyethylene

Damp proofing

Rigid insulation

Treated

wood nailer

Polyethylene or 

damp proofing 

capillary break

Rigid insulation

Rigid insulation

Damp proofing

Continuous

polyethylene

Polyethylene or 

damp proofing 

capillary break

Sill gasket membrane

(also serves as capillary break)

Metal termite flashing

Concrete footing

below frost depth

Polyethylene or damp

proofing capillary Break

Rigid fiberglass insulation

Polyethylene vapor

diffusion retarder

Damp proofing

Perforated drainage

pipe embedded in

coarse gravel

Radon reduction

3” plastic vent pipe

Cavity insulation

Cover insulation

exposed above grade

Rigid insulation

with foil facing

Damp proofing

Cavity

insulation

Polyethylene or

damp proofing

capillary break

EXTERIOR CRAWLSPACE INSULATION INTERIOR CRAWLSPACE INSULATION

If depth does not extend two feet below grade, place 

remaining insulation horizontally along the ground.

EXTERIOR BASEMENT INSULATION

INTERIOR BASEMENT INSULATION

See more information on the following page.

14.9

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.9
Sources & Additional Information

IBACOS. 2002. Consider the Crawlspace (www.buildingamerica.gov)

IBACOS. 2002. Don’t Forget About the Basement (www.buildingamerica.gov)

Lstiburek, Joseph. 2004. Builders Guide to Cold Climates (www.eeba.org/bookstore)

U.S. DOE, Technology Fact Sheet: Basement Insulation (www.buildingamerica.gov)

U.S. DOE, Technology Fact Sheet: Crawlspace Insulation (www.buildingamerica.gov)

U.S. EPA, Building Radon Out: A Step-By-Step Guide on How to Build Radon Resistent Homes (www.epa.gov/1999/iaq/radon)

Yost and Lstiburek. 2002. Basement Insulation Systems (www.buildingamerica.gov)

•	 Keep all untreated wood materials

away from contact with earth 

and concrete. 

•	 Design the house structure with

overhangs, gutters, drainage planes, 

and flashing to shed rainwater and 

conduct it away from the house.

•	 Slope the earth away from the house

and ensure that no irrigation strikes 

near the foundation. 

•	 Damp-proof all below-grade portions of

the exterior foundation wall to prevent 

the absorption of ground water.

•	 Use a sill gasket for air sealing.

•	 Install a protective shield such as

metal flashing, a plastic L bracket, or 

a membrane (such as EPDM flexible 

roofing material*) to block capillary 

water wicking into the wall from the 

foundation. The protective shield may 

also serve as a termite shield.

•	 Crawlspaces require a foundation

drain when the crawlspace floor is 

located below grade. Always install a 

foundation drain in basements. Install 

a foundation drain alongside the 

footing (not above it). The drain should 

rest in a bed of coarse gravel (no fines) 

that slopes away from the foundation 

and is covered with filter fabric.

•	 Exterior rigid fiberglass insulation

may provide a drainage plane that will 

channel water to the foundation drain 

and relieve hydrostatic pressure. 

•	 Exterior foundation wall insulation

requires a protective coating at 

above-grade applications. Examples 

of protective coverings for exterior, 

above-grade insulation include 

flashing, fiber-cement board, parging 

(stucco type material), treated plywood, 

or membrane material (EPDM* flexible roofing). 

•	 Note that some code jurisdictions

may require a gap between exterior 

insulation and wood foundation 

elements to provide a termite 

inspection area.

•	 Install damp proofing or a polyethylene

sheet over the footing to block 

capillary water from wicking into the 

foundation side wall.

•	 Install a capillary break and vapor

retarder under slabs and basement 

floors consisting of at least a 6-mil 

polyethylene sheet or continuous rigid 

foam insulation approved for belowgrade applications, on top of 4 to 6 

inches of coarse gravel.

•	 Install radon control measures

(check local requirements and EPA 

recommendations). 

*EPDM = Ethylene Propylene Diene Monomer. 

Crawlspace and Basement Foundation System Insulation, Moisture, and Air Leakage Control

•	 Exterior and interior insulation approaches may be combined to provide needed insulation levels.

•	 Properly installed exterior rigid fiberglass insulation provides the best moisture management properties of the available insulation types.

•	 Interior nailing strips for finished walls should be installed over interior rigid foam insulation (extruded polystyrene is more moisture

tolerant than expanded polystyrene) so that the foam is sandwiched between the nailing strip and the basement wall. 

•	 When interior foam insulation is applied directly to foundation walls, seal joints in the foam panels with adhesive or mastic.

•	 If interior blanket or batt insulation is used, it should be combined with exterior or interior rigid insulation attached directly to the

foundation wall. The blanket or batt insulation should be unfaced or have a facing that allows moisture to pass through. In a conditioned 

basement, the insulation should be covered with drywall that is tightly air sealed to keep interior moist air from condensing on the 

foundation wall.

Installation Tips

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.10 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Figure Source: Building Science Corporation. 

For technical details, see www.buildingscience.com/documents/profiles/etw-charlotte-profile

Building Profiles: Mixed-Humid Climate – Charlotte, North Carolina

14.11

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.11
Building Profiles: Mixed-Humid Climate – Atlanta, Georgia

Figure Source: Building Science Corporation. 

For technical details, see www.buildingscience.com/documents/profiles/etw-atlanta-profile

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.12 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Building Profiles: Mixed-Humid Climate – Louisville, Kentucky

Figure Source: Building Science Corporation. 

For technical details, see www.buildingscience.com/documents/profiles/etw-louisville-profile

14.13

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.13
Building Profiles: Mixed-Humid Climate – Montgomery County, MD

Figure Source: Building Science Corporation. 

For technical details, see www.buildingscience.com/documents/profiles/etw-montgomery-profile

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.14 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Sources & Additional Information

Building Science Corporation. 2010. “Enclosures That Work: Building Profiles,” Building Science Corporation, 

www.buildingscience.com/doctypes/enclosures-thatwork/etw-building-profiles

Lstiburek, J. W. 2000. Builders Guides. Minneapolis, MN. Energy and Environmental Building Association. www.eeba.org. 

Rigid Insulation

(minimum 1/2" thick)

Wood Furring

(minimum 3/4" thick)

Gypsum Board 

Masonry Wall 

Shallow Electrical Box

(surface-mounted on 

masonry interior)

Continuous 2x4 or 2x2 Horizontal Furring 

(acting as draft or fire stop; seal all 

service/wiring penetrations) 

Interior Gypsum Board with 

permeable or semi-permeable finish 

Semi-Permeable Rigid Insulation

(expanded polystyrene, extruded polystyrene, 

fiber-faced isocyanurate)

Wood Furring 

Gypsum Board 

Concrete 

Slab 

Latex Paint or other permeable or 

semi-permeable interior finish 

Masonry 

Wall 

Sloping Precast Masonry 

Sill with Precast Rib 

Treated Wood Spacer/Mounting 

Block to support window 

Sealant forming 

end dam 

Wood Sub-Jamb

(Positioned toward wall exterior so that face of interior window 

frame is flush with center point of rib in precast masonry sill)

Treated Wood 

Sub-Jamb 

Mounting Member 

("back-caulked") 

Sealant between 

masonry opening and 

treated wood sub-jamb 

Semi-vapor permeable rigid insulations used on the interior 

of wall assemblies should be unfaced or faced with permeable 

skins. Foil facings and polypropylene skins should be avoided.

Wood furring should be installed over rigid insulation; the 

rigid insulation should be continuous over the surface of the wall, 

except for the 2x4 furring near the ceiling. This blocking attaches 

directly to the masonry block and is above the insulation, not behind it.

Electrical boxes can be surface-mounted, 

eliminating chiseling or chipping masonry ELECTRICAL BOX 

WINDOW SILL DRAINAGE 

Source: EEBA 9.5 

Source: EEBA 9.7 

Source: EEBA 9.1 

Masonry Construction

14.15

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.15
(THIS PAGE INTENTIONALLY LEFT BLANK)

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.16 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Housewrap

Example of housewrap strategies

Minimize cuts in housewrap and seal all penetrations with tape or caulk.

Unroll sideways around house.

Fasten flaps of window "T-cut" 

to the inside of the framing.

Seal spigot 

at opening.

Tape housewrap according to manufacturer’s specifications at top plate,

 band joist, and horizontal seams, and secure with plastic-capped nails.

Housewrap should 

be overlapped shingle style.

Seal overlap with tape.

Overlap and seal housewrap 

to foundation side wall 

or flashing.

Caulk under housewrap 

and seal gap between 

electrical box and 

sheathing.

Seal floodlight 

at opening.

HOUSEWRAP 

HOUSEWRAP 

HOUSEWRAP 

HOUSEWRAP 

HOUSEWRAP 

HOUSEWRAP 

HOUSEWRAP 

HOUSEWRAP 

HOUSEWRAP 

HOUSEWRAP 

HOUSEWRAP 

HOUSEWRAP 

HOUSEWRAP 

HOUSEWRAP 

CAULK 

CAULK 

CAULK 

WINDOW 

Housewrap

Plastic-capped nails

Housewrap Tape

Sheathing

Tape

Housewrap Caulk

Sill Gasket

14.17

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.17
•	Do follow manufacturer’s instructions.

•	Do lap all layers properly—the upper layer should always be lapped over the lower layer.

•	Do weatherboard-lap horizontal joints at least 6 inches.

•	Do lap vertical joints 6 to 12 inches (depending on the potential for wind-driven rain).

•	Do use 1-inch minimum staples or housewrap nails spaced 12 to 18 inches throughout.

•	Do tape joints with housewrap tape.

•	Do allow drainage at the bottom of the siding.

•	Do extend housewrap over the sill plate and foundation joint.

• Do install housewrap such that water will never be allowed to flow to the inside of the wrap.

•	Do avoid complicated details in the design stage to prevent water-intrusion problems.

•	When sealant is required:

•	do use backing rods as needed,

•	do use sealant that is compatible with the climate, and materials it is being applied to,

•	do make sure surfaces are clean (free of dirt and loose material).

•	Do integrate wrap correctly with window flashing so that wrap goes over top edge of flashing.

•	Don’t forget to cover the gable ends.

•	Don’t forget to cover the band joists. If you wrap the wall before standing it, go back and insert 

a strip of house wrap to cover the band joist. The strip should extend 6 to 12 inches underneath 

the bottom edge of the wall wrap. 

•	Don’t forget to cover outside corners. Do overlap wrap 6 to 12 inches at corners.

•	Don’t rely on caulk or self-sticking tape to “fix” improper lapping of housewrap. Caulk will fail over time.

DO’s and DON’Ts of Housewrap

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.18 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Window Flashing

Window flashing details for home with housewrap and plywood or OSB wall sheathing

>12" >10"

Housewrap

Cap Nails 45 ̊ 6"

6"

CAULK

HOUSEWRAP 

HOUSEWRA

HOUSEWRAP 

HOUSEWRAP 

Self-adhesive 

Window Flashing

Tape

HOUSEWRAP 

HOUSEWRA

HOUSEWRAP 

HOUSEWRAP 

HOUSEWRAP

HOUSEWRAP 

HOUSEWRAP 

EWRAP 

HOUSEWRAP 

HOUSEWRAP 

HOUS

HOUSEWRAP 

HOUSEWRAP 

OUSEWRAP 

HOUSEWR

HOUSEWRAP 

HOUSEWRAP

>12" >10"

Housewrap

Cap Nails 45 ̊ 6"

6"

CAULK

HOUSEWRAP 

HOUSEWRA

HOUSEWRAP 

HOUSEWRAP 

Self-adhesive 

Window Flashing

Tape

HOUSEWRAP 

HOUSEWRA

HOUSEWRAP 

HOUSEWRAP 

HOUSEWRAP

HOUSEWRAP 

HOUSEWRAP 

EWRAP 

HOUSEWRAP 

HOUSEWRAP 

HOUS

HOUSEWRAP 

HOUSEWRAP 

OUSEWRAP 

HOUSEWR

HOUSEWRAP 

HOUSEWRAP

STEP 1 - 

IF HOUSEWRAP HAS NOT YET BEEN INSTALLED

STEP 2 - SILL FLASHING STEP 3 - JAMB CAULKING

• Apply at least a 12-inch flap, or apron, of building paper or 

housewrap just below the window sill.

• If the window sill is close to the sill plate, the apron can extend all 

the way to the sill plate.

• The apron should extend at least 10 inches past the sides of the 

window opening, or to the first stud in open wall construction.

• Attach only the apron’s top edge with cap nails.

• Install self-adhesive flashing to the sill, ensuring that the 

flashing extends up jambs at least 6 inches.

• One commercial product comes with two removable strips 

over the adhesive. Remove the first strip to expose half of the 

adhesive and apply this area to the sill. Begin pressing in the 

middle of the sill and work towards the sides. Remove the 

second strip to expose the adhesive that will be used to apply 

the flashing below the window to the outside wall.

• Tape down the bottom corners of the flashing.

• Caulk the outside edges of the head and side jambs.

• Do not caulk across the sill.

• Install the window using corrosion-resistant nails and 

following manufacturer’s specifications.

• Cut the housewrap covering the rough opening in 

the shape of a modified “Y.”

• Fold the side and bottom flaps into the window 

opening and secure.

• Above the window opening, cut a head flap and 

flip it up to expose sheathing, and loosely tape in 

place out of the way.

STEP 1 - 

IF HOUSEWRAP HAS BEEN INSTALLED

14.19

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.19
CAULK

4" 1" HOUSEWRAP 

HOUSEWRAP 

HOUS

HOUSEWRAP 

HOUSEWRAP 

OUSEWRAP 

HOUSEWR

Self-adhesive 

head flashing

Fold down

head flap

HOUSEWRAP

HOUSEWRAP

HOUSEWRA

HOUSEWRAP

HOUSEWRAP

HOUSEWRAP

HOUSEWRAP

Housewrap

secured to 

window flange 

with tape HOUSEW

HOUSE

HOUSEWRAP

HOUSEWRAP

Self-adhesive 

jamb flashing

Existing

apron

Head flap 

secured with tape

STEP 4 - JAMB AND HEAD FLASHING STEP 5 - SEAL ROUGH OPENING GAP

• Install self-adhesive jamb flashing extending 4 inches above 

the top of the head flange and even with the bottom of the 

sill flashing.

• Install self-adhesive head flashing extending 1 inch beyond 

the jamb flashing.

• If housewrap has been installed, be sure that the head flap, 

when it is folded down, will cover the top of the flashing.

• On the interior side of the window, seal the gap 

between the window and the rough opening with 

a backer rod or non-expanding foam and caulk. 

STEP 6 - IF APRON WAS INSTALLED STEP 6 - IF HEAD FLAP WAS CREATED

• If an apron was installed under the window, slip the 

housewrap or building paper under the apron.

• Tape the edges where the housewrap meets the 

window flange if housewrap is installed after flashing.

• If building paper is used, embed the edges in a bead 

of sealant where the paper meets the window flange.

• If a head flap was created, fold it over the head 

flashing and tape across the top window flange and 

the 45° angle seams.

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.20 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Wall-to-Roof Flashing

Kick-Out Diverter Flashing Details – Housewrap Installed Over OSB or Plywood as Water-Resistive Barrier

Water runoff from rain storms can run along roof-wall intersections and spill over gutters to flow down exterior walls. If flashing is 

lacking or inadequate, this water runoff can get inside the wall and cause serious damage. Anywhere roof sections adjoin wall sections, 

side-wall flashing should be used to keep water from entering the walls and kick-out diverters should be used to direct the rain water 

into rain gutters where it can be carried down and away from the structure. The kick-out flashing should be seamless and sized 

(as shown in the photos below) to effectively manage large volumes of water run-off associated with torrential rains from a variety 

of roof pitches, with an appropriate expected service life to avoid premature failures. (Photos Source: DryFlekt Products, Inc.)

STEP 1 Apply drip edge and roof 

underlayment over roof deck. Continue 

lapping up the sidewall and over the 

water-resistive barrier (in this case 

housewrap) a minimum of 6 inches.

STEP 4 Install remaining sidewall 

flashing, appropriate counter flashing, 

and shingles in accordance with 

manufacturer’s instructions.

STEP 2 Install shingle starter strip at 

roof eave in accordance with roofing 

manufacturer’s instructions.

•	 Place seamless one-piece of non-corrosive 

kick-out diverter flashing as the first piece 

of step flashing. 

•	 Slide kick-out diverter up roof plane until the 

starter trough stops at the shingle starter strip.

•	 The diverter must be flat on the roof and 

flush to the sidewall.

•	 Fasten and seal diverter to the roof deck and 

starter strip. (Do not fasten to the sidewall.)

STEP 5 Apply self-adhesive flashing 

over top of wall flashing, diverter, and 

housewrap.

STEP 3 Place first shingle and next 

section of sidewall flashing over the

up-slope edge of diverter, lapping a 

minimum of 4 inches over diverter. 

(Sidewall flashing height requirement 

should be determined by design 

professional and local building codes.)

STEP 6 Install house wrap; cut the 

house wrap to fit over the self-adhesive 

flashing and sidewall flashing.

STEP 7 Apply siding over housewrap.

14.21

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.21
Wall-to-Roof Flashing

Kick-Out Diverter Flashing Details - Rigid Foam Insulation Installed as a Water-Resistive Barrier

Water runoff from rain storms can run along roof-wall intersections and spill over gutters to flow down exterior walls. If flashing is 

lacking or inadequate, this water runoff can get inside the wall and cause serious damage. Anywhere roof sections adjoin wall sections, 

side-wall flashing should be used to keep water from entering the walls and kick-out diverters should be used to direct the rain water 

into rain gutters where it can be carried down and away from the structure. The kick-out flashing should be seamless and sized 

(as shown in the photos below) to effectively manage large volumes of water run-off associated with torrential rains from a variety 

of roof pitches, with an appropriate expected service life to avoid premature failures. (Photos Source: DryFlekt Products, Inc.)

STEP 1 Apply drip edge and roof 

underlayment over roof deck and 

continue lapping up the sidewall and 

over the water-resistive barrier (in this 

case rigid foam insulation) a minimum 

of 7 inches.

STEP 4 Install remaining sidewall 

flashing, appropriate counter flashing 

and shingles in accordance with 

manufacturer’s instructions.

STEP 2 Install shingle starter strip at 

roof eave in accordance with roofing 

manufacturer’s instructions.

•	 Place seamless, one-piece, non-corrosive 

kick-out diverter flashing as the first piece 

of step flashing.

•	 Slide kick-out diverter up roof plane until the 

starter trough stops at the shingle starter strip.

•	 Diverter must be flat on the roof and flush 

to the sidewall.

•	 Fasten and seal diverter to the roof deck and 

starter strip. (Do not fasten to the sidewall.)

STEP 5 Apply self adhesive flashing 

over top of wall flashing, diverter and 

rigid foam insulation.

STEP 3 Place first shingle and 

next section of sidewall flashing over 

up-slope edge of diverter, lapping a 

minimum of 4” over diverter. 

(Sidewall flashing height requirement 

should be determined by design 

professional and local building codes.)

STEP 6 Apply construction tape 

over the self-adhered flashing. 

STEP 7 Apply siding over rigid 

foam insulation.

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.22 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Interior Air Sealing

Conventional construction requires tracking down and sealing multiple 

air leaks that ultimately lead to or through the exterior shell.

Sill Plate & Rim Joist

Stairs

Wall & Ceiling Drywall

Kneewalls

Windows

ICAT Can Light

Electric Circuit Box

Outlets & Switches

Fireplace

Plumbing Penetrations

Attic Access

Doors

Cantilever

Skylight

Crawlspace Access

Registers

Exhaust Fan 

Garage Common Wall

Wall Adjoining Cavity

Tub

Interior Soffit

Plywood Floor Panels

12

7

18

4

20

5

13

14

15

21 17

9

11

10

2

3

22

1

6

8 19

16

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

14.23

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.23
Tape

Housewrap Caulk

Sil gasket

Gypsum

board

Structural

sheathing

Tape and joint

compound seal

Bottom plate caulked

or gasketed to subfloor

Drywall caulked, glued 

or gasketed to bottom plate

Drywall caulked or glued 

to top plate

Ceiling drywall taped

to wall drywall

Use rigid foam 

or sheet goods to 

seal joist cavities

Seal

Adhesive, Gasket or Caukling

Drywall

Hardboard, 

rigid foam, 

or sheet goods

Seal

HOUSEWRAP

HOUS

OUSEWRAP

HOUSEWRAP

Before installing 

the window, caulk 

the outside edges 

of the head and 

side jambs

Do not caulk

across the sill

CAULK

CAULK

Seal gap between 

window and rough

opening on interior

Recessed light fixtures 

should be rated for 

Insulated Ceiling Air 

Tight (ICAT).

AIR TIGHTNESS 

LABEL

Airtight wire 

connection from 

junction jox

Airtight

can

Decorative

cover Caulk

or gasket

Seal

Support sheathing

Electrical

panel

Seal wire

connection

Nailing

flange Built-in

sealant

Flange for sealing to 

drywall air barrier

Select boxes with 

built-in gasket 

and sealant

Seal

Solid air barrier

material sealed at

perimeter and seams

CAULK

Air seal gasket

Rigid insulation

Attic

Use ENERGY STAR

labeled door

Baseplate sealed 

to subfloor

Blocking between joists,

sealed at perimeter

Insulation in permanent

contact with subfloor

Tape

Rim joist Rigid or blown-in

foam insulation

Housewrap

Sill gasket

CAULK

Tape

Housewrap Caulk

Sil gasket

Gypsum

board

Structural

sheathing

Tape and joint

compound seal

Bottom plate caulked

or gasketed to subfloor

Drywall caulked, glued 

or gasketed to bottom plate

Drywall caulked or glued 

to top plate

Ceiling drywall taped

to wall drywall

Use rigid foam 

or sheet goods to 

seal joist cavities

Seal

Adhesive, Gasket or Caukling

Drywall

Hardboard, 

rigid foam, 

or sheet goods

Seal

HOUSEWRAP

HOUS

OUSEWRAP

HOUSEWRAP

Before installing 

the window, caulk 

the outside edges 

of the head and 

side jambs

Do not caulk

across the sill

CAULK

CAULK

Seal gap between 

window and rough

opening on interior

Recessed light fixtures 

should be rated for 

Insulated Ceiling Air 

Tight (ICAT).

AIR TIGHTNESS 

LABEL

Airtight wire 

connection from 

junction jox

Airtight

can

Decorative

cover Caulk

or gasket

Seal

Support sheathing

Electrical

panel

Seal wire

connection

Nailing

flange Built-in

sealant

Flange for sealing to 

drywall air barrier

Select boxes with 

built-in gasket 

and sealant

Seal

Solid air barrier

material sealed at

perimeter and seams

CAULK

Rigid insulation

Attic

Use ENERGY STAR

labeled door

Baseplate sealed 

to subfloor

Insulation in permanent

contact with subfloor

Tape

Rim joist Rigid or blown-in

foam insulation

Housewrap

Sill gasket

CAULK

Tape

Housewrap Caulk

Sil gasket

Gypsum

board

Structural

sheathing

Tape and joint

compound seal

Bottom plate caulked

or gasketed to subfloor

Drywall caulked, glued 

or gasketed to bottom plate

Drywall caulked or glued 

to top plate

Ceiling drywall taped

to wall drywall

Use rigid foam 

or sheet goods to 

seal joist cavities

Seal

Adhesive, Gasket or Caukling

Drywall

Hardboard, 

rigid foam, 

or sheet goods

Seal

HOUSEWRAP

HOUS

OUSEWRAP

HOUSEWRAP

Before installing 

the window, caulk 

the outside edges 

of the head and 

side jambs

Do not caulk

across the sill

CAULK

CAULK

Seal gap between 

window and rough

opening on interior

Recessed light fixtures 

should be rated for 

Insulated Ceiling Air 

Tight (ICAT).

AIR TIGHTNESS 

LABEL

Airtight wire 

connection from 

junction jox

Airtight

can

Decorative

cover Caulk

or gasket

Seal

Support sheathing

Electrical

panel

Seal wire

connection

Nailing

flange Built-in

sealant

Flange for sealing to 

drywall air barrier

Select boxes with 

built-in gasket 

and sealant

Seal

Solid air barrier

material sealed at

perimeter and seams

CAULK

Rigid insulation

Attic

Use ENERGY STAR

labeled door

Baseplate sealed 

to subfloor

Insulation in permanent

contact with subfloor

Tape

Rim joist Rigid or blown-in

foam insulation

Housewrap

Sill gasket

CAULK

Tape

Housewrap Caulk

Sil gasket

Gypsum

board

Structural

sheathing

Tape and joint

compound seal

Bottom plate caulked

or gasketed to subfloor

Drywall caulked, glued 

or gasketed to bottom plate

Drywall caulked or glued 

to top plate

Ceiling drywall taped

to wall drywall

Use rigid foam 

or sheet goods to 

seal joist cavities

Seal

Adhesive, Gasket or Caukling

Drywall

Hardboard, 

rigid foam, 

or sheet goods

Seal

HOUSEWRAP

HOUS

OUSEWRAP

HOUSEWRAP

Before installing 

the window, caulk 

the outside edges 

of the head and 

side jambs

Do not caulk

across the sill

CAULK

CAULK

Seal gap between 

window and rough

opening on interior

Recessed light fixtures 

should be rated for 

Insulated Ceiling Air 

Tight (ICAT).

AIR TIGHTNESS 

LABEL

Airtight wire 

connection from 

junction jox

Airtight

can

Decorative

cover Caulk

or gasket

Seal

Support sheathing

Electrical

panel

Seal wire

connection

Nailing

flange Built-in

sealant

Flange for sealing to 

drywall air barrier

Select boxes with 

built-in gasket 

and sealant

Seal

Solid air barrier

material sealed at

perimeter and seams

CAULK

Attic

Use ENERGY STAR

Baseplate sealed 

to subfloor

Insulation in permanent

Tape

Rim joist Rigid or blown-in

foam insulation

Housewrap

Sill gasket

CAULK

7

10

4 5

9

1 2 3

6

8

Sill Plate & Rim Joist

Kneewalls

Electric Circuit Box

Plumbing Penetrations

Stairs

Windows

Outlets & Switches

Wall & Ceiling Drywall

ICAT Can Light

Fireplace

Direct vent fireplace through outside wall; 

no chimney needed, but seal fireplace alcove.

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.24 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Flange for sealing to 

drywall air barrier

built-in gasket 

and sealant

Seal

material sealed at 

parimeter and seams

Air seal gasket

between trim

and panel

Rigid insulation

Attic

Use ENERGY STAR

labeled door

Install automatic

closer and gasket

or weatherstripping

Baseplate sealed 

to subfloor

Blocking between joists,

sealed at perimenter

Insulation in permanent

contact with subfloor

Rigid insulation

Air seal gasket

Crawlspace

Rigid insulation

REGISTER

Seal all joints in 

boot and elbow

with mastic

Seal boots to 

sheet goods with 

caulk, mastic, or 

spray foam

CAULK

EXHAUST FAN If fan exhausts or 

draws air through 

sidewall, install hood

with louvered 

damper

Bottom plate caulked

or gasketed to subfloor

Drywall caulked, glued 

or gasketed; inside seam 

taped and mudded

GARAGE

Bottom plate caulked

or gasketed to subfloor

 on interior, exterior,

or both surfaces

Drywall caulked, 

glued or gasketed 

to top plate on interior, 

exterior, or both surfaces 

CAVITY

Continuous bead of

sealant or adhesive

Thin sheet goods 

as draftstop behind

tub or enclosure

Blocking

Solid air barrier

material sealed

at perimeter

CAULK

Use caulk or adhesive to

seal panels to joists at seams

sealant

Flange for sealing to 

drywall air barrier

Select boxes with 

built-in gasket 

and sealant

Seal

Solid air barrier

material sealed at 

parimeter and seams

CAULK

Air seal gasket

between trim

and panel

Rigid insulation

Attic

Use ENERGY STAR

labeled door

Install automatic

closer and gasket

or weatherstripping

Baseplate sealed 

to subfloor

Blocking between joists,

sealed at perimenter

Insulation in permanent

contact with subfloor

Rigid insulation

Air seal gasket

Crawlspace

Rigid insulation

REGISTER

Seal all joints in 

boot and elbow

with mastic

Seal boots to 

sheet goods with 

caulk, mastic, or 

spray foam

CAULK

EXHAUST FAN If fan exhausts or 

draws air through 

sidewall, install hood

with louvered 

damper

Bottom plate caulked

or gasketed to subfloor

Drywall caulked, glued 

or gasketed; inside seam 

taped and mudded

GARAGE

Bottom plate caulked

or gasketed to subfloor

 on interior, exterior,

or both surfaces

Drywall caulked, 

glued or gasketed 

to top plate on interior, 

exterior, or both surfaces 

CAVITY

Continuous bead of

sealant or adhesive

Thin sheet goods 

as draftstop behind

tub or enclosure

Blocking

Solid air barrier

material sealed

at perimeter

CAULK

Use caulk or adhesive to

seal panels to joists at seams

Flange for sealing to 

drywall air barrier

Select boxes with 

built-in gasket 

and sealant

Seal

Solid air barrier

material sealed at 

parimeter and seams

CAULK

Air seal gasket

between trim

and panel

Rigid insulation

Attic

Use ENERGY STAR

labeled door

Install automatic

closer and gasket

or weatherstripping

Baseplate sealed 

to subfloor

Blocking between joists,

sealed at perimenter

Insulation in permanent

contact with subfloor

Rigid insulation

Air seal gasket

Crawlspace

Rigid insulation

REGISTER

Seal all joints in 

boot and elbow

with mastic

Seal boots to 

sheet goods with 

caulk, mastic, or 

spray foam

CAULK

EXHAUST FAN If fan exhausts or 

draws air through 

sidewall, install hood

with louvered 

damper

Bottom plate caulked

or gasketed to subfloor

Drywall caulked, glued 

or gasketed; inside seam 

taped and mudded

GARAGE

Bottom plate caulked

or gasketed to subfloor

 on interior, exterior,

or both surfaces

Drywall caulked, 

glued or gasketed 

to top plate on interior, 

exterior, or both surfaces 

CAVITY

Continuous bead of

sealant or adhesive

Thin sheet goods 

as draftstop behind

tub or enclosure

Blocking

Solid air barrier

material sealed

at perimeter

CAULK

Use caulk or adhesive to

seal panels to joists at seams

Flange for sealing to 

drywall air barrier

Select boxes with 

built-in gasket 

and sealant

Seal

Solid air barrier

material sealed at 

parimeter and seams

Air seal gasket

between trim

and panel

Rigid insulation

Attic

Use ENERGY STAR

labeled door

Install automatic

closer and gasket

or weatherstripping

Baseplate sealed 

to subfloor

Blocking between joists,

sealed at perimenter

Insulation in permanent

contact with subfloor

Rigid insulation

Air seal gasket

Crawlspace

Rigid insulation

REGISTER

Seal all joints in 

boot and elbow

with mastic

Seal boots to 

sheet goods with 

caulk, mastic, or 

spray foam

CAULK

EXHAUST FAN If fan exhausts or 

draws air through 

sidewall, install hood

with louvered 

damper

Bottom plate caulked

or gasketed to subfloor

Drywall caulked, glued 

or gasketed; inside seam 

taped and mudded

GARAGE

Bottom plate caulked

or gasketed to subfloor

 on interior, exterior,

or both surfaces

Drywall caulked, 

glued or gasketed 

to top plate on interior, 

exterior, or both surfaces 

CAVITY

Continuous bead of

sealant or adhesive

Thin sheet goods 

as draftstop behind

tub or enclosure

Blocking

Solid air barrier

material sealed

at perimeter

CAULK

Use caulk or adhesive to

seal panels to joists at seams

12

15

18

21

13

16

19

22

11

14

17

20

Attic Access

Skylight

Exhaust Fan

Tub

Doors

Crawlspace Access

Garage Common Wall

Interior Soffit

Cantilever

Registers

Wall Adjoining Cavity

Plywood Floor Panels

14.25

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CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.26 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Exterior Air Sealing with Insulating Sheathing Panels

This figure shows an approach to construction used in some Building America homes. The red line represents the 

thermal boundary, which is provided here by rigid foam insulation that is on the external side of the walls and the 

interior side of the foundation walls and roof. This exterior insulating sheathing provides both an air and thermal 

barrier for the walls. The non-vented attic is sealed and insulated along the roofline. Particular attention is paid to the 

intersection of the foundations, walls, and roof.

5

3

4

6

7

2

 1. Sillplate & Rim Joist

 2. Windows

 3. Plumbing Penetrations

 4. Doors

 5. Exhaust Fan 

 6. Garage Common Wall

 7. Tub

Furring strip

Cladding

Tape seams

Caulk edges

CAULK

Insulated

sheathing panels

Insulating Sheathing Detail

1

1

2

3

4

5

6

7

14.27

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.27
Tape

Housewrap Caulk

Sil gasket

Gypsum

board

Structural

sheathing

Tape and joint

compound seal

Bottom plate caulked

or gasketed to subfloor

Drywall caulked, glued 

or gasketed to bottom plate

Drywall caulked, glued 

or gasketed to top plate

Ceiling drywall taped

to wall drywall

Use rigid foam 

or sheet goods to 

seal joist cavities

Seal

Hardboard

Seal

HOUSEWRAP

HOUSEWRAP

HOUSEWRAP

HOUSEWRAP

Before installing 

the window, caulk 

the outside edges 

of the head and 

side jambs

Do not caulk

across the sill

CAULK

CAULK

Seal gap between 

window and rough

opening on interior

Recessed light fixtures 

should be rated for 

Insulated Ceiling Air 

Tight (ICAT).

AIR TIGHTNESS 

LABEL

Airtight wire 

connection from 

junction jox

Airtight

can

Decorative

cover Caulk

or Gasket

Sealant

Support sheathing

Electrical

panel

Seal wire

connection

Nailing

flange Built-in

sealant

Flange for sealing to 

drywall air barrier

Select boxes with 

built-in gasket 

and sealant

Seal

Solid air barrier

material sealed at 

parimeter and seams

CAULK

Rigid insulation

Attic

Use ENERGY STAR

Install automatic

closer and gasket

or weatherstripping

Baseplate sealed 

to subfloor

Insulation in permanent

contact with subfloor

Tape

Rim joist Rigid or blown-in

foam insualtion

Housewrap

Sill gasket

CAULK

Tape

Sil gasket

board

Structural

sheathing

Bottom plate caulked

or gasketed to subfloor

Drywall caulked, glued 

or gasketed to bottom plate

gp p

Use rigid foam 

or sheet goods to 

seal joist cavities

Seal

Hardboard

Seal

HOUSEWRAP

HOUSEWRAP

HOUSEWRAP

HOUSEWRAP

Before installing 

the window, caulk 

the outside edges 

of the head and 

side jambs

Do not caulk

across the sill

CAULK

CAULK

Seal gap between 

window and rough

opening on interior

Recessed light fixtures 

should be rated for 

Insulated Ceiling Air 

Tight (ICAT).

AIR TIGHTNESS 

LABEL

Airtight wire 

connection from 

junction jox

Airtight

can

Decorative

cover Caulk

or Gasket

Sealant

Support sheathing

Electrical

panel

Seal wire

connection

Nailing

flange Built-in

sealant

Flange for sealing to 

drywall air barrier

Select boxes with 

built-in gasket 

and sealant

Seal

Solid air barrier

material sealed at 

parimeter and seams

CAULK

Air seal gasket

between trim

and panel

Rigid insulation

Attic

Use ENERGY STAR

labeled door

Install automatic

closer and gasket

or weatherstripping

Baseplate sealed 

to subfloor

Blocking between joists,

sealed at perimenter

Insulation in permanent

contact with subfloor

Air seal gasket

Rigid insulation

REGISTER

Seal all joints in 

Seal boots to 

sheet goods with 

caulk, mastic, or 

spray foam

Tape

Rim joist Rigid or blown-in

foam insualtion

Sill gasket

Use rigid foam 

or sheet goods to 

seal joist cavities

Seal

Hardboard

Seal

HOU

HOUSEWRAP

HOUSEWRAP

oe ead ad 

side jambs

Do not caulk

across the sill

CAULK

CAULK

Seal gap between 

window and rough

opening on interior

AIR TIGHTNESS 

LABEL

Airtight

can

Caulk

or Gasket

Suppor

Elect

pan

Seal wire

connection

Nailing

flange Built-in

sealant

Flange for sealing to 

drywall air barrier

Select boxes with 

built-in gasket 

and sealant

Seal

Solid air barrier

material sealed at 

parimeter and seams

CAULK

Air seal gasket

between trim

and panel

Rigid insulation

Attic

Use ENERGY STAR

labeled door

Install automatic

closer and gasket

or weatherstripping

Basepla

to subfl

Blocking betwee

sealed at per

Insulation in per

contact with su

Rigid insulation

Air seal gasket

Crawlspace

Rigid insulation

REGISTER

Drywall caulked, glued 

or gasketed; inside seam 

taped and mudded

GARAGE

Drywall caulked, 

glued or gasketed 

to top plate on interior, 

exterior, or both surfaces 

1 Sill Plate & Rim Joist 2 Windows

HOUSEWRAP

P

en 

ugh

rior

g

should be rated for 

Insulated Ceiling Air 

Tight (ICAT).

AIR TIGHTNESS 

LABEL

Airtight wire 

connection from 

junction jox

Airtight

can

Decorative

cover Caulk

or Gasket

Sealant

Support sheathing

Electrical

panel

Seal wire

connection

Seal

s

CAULK

omatic

 gasket

rstripping

Baseplate sealed 

to subfloor

Blocking between joists,

sealed at perimenter

Insulation in permanent

contact with subfloor

REGISTER

Seal all joints in 

boot and elbow

with mastic

Seal boots to 

sheet goods with 

caulk, mastic, or 

spray foam

ued 

3 Plumbing Penetrations 4 Doors

Seal

Hardboard

Seal

CAULK

Seal gap between 

window and rough

opening on interior

Sealant

Support sheathing

Electrical

panel

Seal wire

connection

Nailing

flange Built-in

sealant

Flange for sealing to 

drywall air barrier

Select boxes with 

built-in gasket 

and sealant

Seal

Solid air barrier

material sealed at 

parimeter and seams

CAULK

Air seal gasket

between trim

and panel

Rigid insulation

Attic

Use ENERGY STAR

labeled door

Install automatic

closer and gasket

or weatherstripping

Baseplate sealed 

to subfloor

Blocking between joists,

sealed at perimenter

Insulation in permanent

contact with subfloor

Rigid insulation

Air seal gasket

Crawlspace

Rigid insulation

REGISTER

Seal all joints in 

boot and elbow

with mastic

Seal boots to 

sheet goods with 

caulk, mastic, or 

spray foam

CAULK

EXHAUST FAN If fan exhausts or 

draws air through 

sidewall, install hood

with louvered 

damper

Bottom plate caulked

or gasketed to subfloor

Drywall caulked, glued 

or gasketed; inside seam 

taped and mudded

GARAGE

Bottom plate caulked

or gasketed to subfloor

 on interior, exterior,

or both surfaces

Drywall caulked, 

glued or gasketed 

to top plate on interior, 

exterior, or both surfaces 

CAVITY

Blocking

6

5

7

Exhaust Fan

Garage Common Wall Tub Plumbing Floor Penetrations

Air seal gasket

between trim

and panel

Rigid insulation

Attic

Use ENERGY 

labeled do

Rigid insulation

Air seal gasket

Cra

Rigid 

CAULK

EXHAUST FAN If fan exhausts or 

draws air through 

sidewall, install hood

with louvered 

damper

Bo

or 

D

o

ta

Continuous bead of

sealant or adhesive

Thin sheet goods 

as draftstop behind

tub or enclosure

Blocking

Solid 

mate

at 

n

t

es with 

ket 

t

Seal

Solid air barrier

material sealed at 

parimeter and seams

CAULK

Use ENERGY STAR

labeled door

Install automatic

closer and gasket

or weatherstripping

Baseplate sealed 

to subfloor

Blocking between joists,

sealed at perimenter

Insulation in permanent

contact with subfloor

Air seal gasket

Crawlspace

Rigid insulation

REGISTER

Seal all joints in 

boot and elbow

with mastic

Seal boots to 

sheet goods with 

caulk, mastic, or 

spray foam

s or 

ugh 

 hood

Bottom plate caulked

or gasketed to subfloor

Drywall caulked, glued 

or gasketed; inside seam 

taped and mudded

GARAGE

Bottom plate caulked

or gasketed to subfloor

 on interior, exterior,

or both surfaces

Drywall caulked, 

glued or gasketed 

to top plate on interior, 

exterior, or both surfaces 

CAVITY

Solid air barrier

material sealed

at perimeter

CAULK

Use caulk or adhesive to

seal panels to joists at seams

Air seal gasket

between trim

and panel

Rigid insulation

Attic

Use ENERGY STAR

labeled door

Install automatic

closer and gasket

or weatherstripping

Baseplate 

to subfloo

Blocking between j

sealed at perim

Insulation in perm

contact with subfl

Rigid insulation

Air seal gasket

Crawlspace

Rigid insulation

REGISTER

Se

bo

wi

Se

sh

ca

sp

CAULK

EXHAUST FAN If fan exhausts or 

draws air through 

sidewall, install hood

with louvered 

damper

Bottom plate caulked

or gasketed to subfloor

Drywall caulked, glued 

or gasketed; inside seam 

taped and mudded

GARAGE

Bottom plate caulked

or gasketed to subfloor

 on interior, exterior,

or both surfaces

Drywall caulked, 

glued or gasketed 

to top plate on interior, 

exterior, or both surfaces 

Continuous bead of

sealant or adhesive

Thin sheet goods 

as draftstop behind

tub or enclosure

Blocking

Solid air barrier

material sealed

at perimeter

CAULK

Use caulk or 

seal panels to jo

Keep pipes out of exterior walls and

seal penetrations through floor.

Keep pipe runs parallel and close to 

studs. Don’t compress insulation.

Insulate pipes exposed

to unconditioned areas

Seal penetrations

through rim joists.

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.28 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Sources & Additional Information

Lstiburek, J. W. 2000. Builders Guides. Energy and Environmental Building Association. www.eeba.org. 

U.S. DOE. Technology Fact Sheet on Air Sealing.

NAHB Research Center. www.toolbase.org: click on New Building Technology > Plumbing > Distribution Systems > Air Admittance Vents

Plumbing 

Vent 

Wall 

Top Plate 

Sealant between 

gasket and plate 

Staples 

Caulk/sealant 

Caulk/ 

Sealant 

Floor Insulation Pipe 

Exterior Wall 

 Rim 

Joist 

Another trade may have 

completed this step. 

Confirm with the site 

supervisor. If not, and 

you need to complete 

the step yourself, ensure 

that the necessary 

materials are available 

onsite.

Vent pipe may be eliminated with an air-admittance valve in some jurisdictions.

Seal all plumbing and electrical penetrations.

Insulate and air seal behind tub.

Draft stop behind enclosure.

Keep pipes out of exterior walls and seal

holes through floor.

Seal holes through rim joists.

Insulate pipes 

 exposed to 

 unconditioned 

 areas

Be careful not to compress or disrupt floor 

insulation, if it is present. Keep pipe runs 

parallel and close to studs, leaving more room 

for insulation.

Prefabricated roof-vent pipe flashing can be adapted as air-sealing gaskets.

Continuous bead 

of sealant or 

adhesive 

Thin sheet 

goods as draft 

stop behind tub 

or enclosure 

Blocking 

CAULK 

Exterior Wall 

Draft Stop 

Plumbing Air Sealing

14.29

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CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.30 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Sources & Additional Information

Lstiburek, J.W. 2000. Builder Guide Hot-Humid Climates. Minneapolis, MN: Energy and Environmental Building Association (ww.eeba.org).

U.S. DOE. Technology Fact Sheet on Air Sealing (www.eere.energy.gov/buildings/documents/pdfs/26448.pdf).

Ceiling fans should be wired to a wall switch.

Seal all exterior penetrations, such as 

porch light fixtures, phone, security, 

cable and electric service holes, with 

caulk, spray foam, or gaskets - note 

that foam degrades in sunlight.

Use air-tight outlet boxes 

or seal standard boxes.

Seal standard plastic 

 electrical box at face 

 to drywall with joint 

 compound or cover 

 the plate gasket 

 with caulk or foam. 

Seal light fixture boxes to drywall with caulk or foam.

Seal bath fan box to drywall 

with caulk or foam.

Caulk/seal/foam all holes for electrical wires 

at top and bottom plates of exterior walls.

Run wiring along bottom plate at exterior wall.

NOTE: Some codes require wires to be held up from 

bottom plates 6"-8" to protect from future drilling through plates.

Run wiring 

along side 

of stud at

exterior wall

and along 

plates

Recessed light fixtures should be rated for Insulated Ceiling Air Tight (ICAT).

AIR TIGHTNESS 

LABEL 

Airtight Wire 

Connection From 

Junction Box 

Airtight Can 

EXTERIOR WALL

Caulk 

Seal Wire

Connection

Sealant

Support Sheathing

Electrical

Panel

Flange for sealing to 

drywall air barrier

Nailing

Flange

Built-in

Gasket

Built-in

Sealant

Caulk

Caulk at wire

penetrations

Decorative 

Cover 

CAULK 

CAULK 

Standard Plastic

Electrical Box

Air Sealed

Electrical Box

AIRTIGHTNESS LABEL 

Electrical Air Sealing

14.31

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CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.32 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Installing Fiberglass Batt Insulation

Always:

 Avoid gaps, tight turns, and compressions.

 Cut insulation to fit snugly in non-standard spaces.

 Slit batts to fit around wiring and plumbing.

 Notch out around electrical boxes and use scraps to fill 

in behind.

•	 Install long runs first – then use scraps to fill in smaller 

spaces and gaps.

•	 Use unfaced batts in humid climates.

•	 Even if blown-in insulation is to be generally applied, 

use fiberglass batts to insulate areas that will be 

inaccessible to the blown-in insulation, such as 

behind bath enclosures and fireplaces.

Walls:

 Friction-fit the batts in place until covered by drywall 

or sheathing.

 Insulate before installing stairs, tubs, and other 

features that will block access.

Knee Walls:

 Seal knee wall to create a continuous air barrier. Close air 

gaps between floor joists under attic rooms. Insulate and 

air seal the rafter space along the sloping ceiling of the 

knee wall attic space or insulate and air seal the roofline, 

wall, and floor.

 Rafters should receive R-19 or R-30 insulation.

 Cover rafters with a sealed air barrier (such as drywall 

or foam board).

 Caulk the barrier to the top plate of the wall below the 

attic space and to the top plate of the knee wall itself.

 Seal all other cracks and holes.

Ceilings:

 Insulate and seal the attic access door

 Install insulation over ICAT-rated recessed cans.

 Verify ventilation pathways.

 Install insulation baffles between attic rafters in vented attics.

Band Joists:

 Place insulation in the cavities between joists and subfloor.

 Caulk bottom plate to subfloor.

 Caulk band joist to subfloor and plates and insulate.

 Caulk bottom plate to subfloor.

Under Floor Insulation:

 An insulated, unvented crawlspace is preferred rather than 

insulating under the floor. If under-floor insulation is to 

be used, it can be held in place with metal staves, lathe, 

stainless steel wire, or twine.

 If truss systems are used under floors, an approach better 

than batt insulation is to install netting or rigid insulation 

to the underside of the floor trusses and fill the joist cavity 

with blown-in insulation.

14.33

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CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.34 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Installing Windows in Walls with External Rigid Foam Insulation

Installing rigid foam insulation on exterior walls reduces thermal bridging and may reduce the chance of condensation in 

wall cavities. Many builders now install 4 or 6 inches of EPS, XPS, or polyisocyanuarate rigid insulation on exterior walls.

Innies or Outies?

Builders installing thick exterior wall foam can install windows two ways: with the window flanges in the same plane as 

the back of the siding or with the window flanges in the same plane as the OSB or plywood wall sheathing.

The following apply to any window installation:

1. Foam panels should be installed with windows in mind—windows should not be installed where there is a 

seam in the foam sheathing, even if the foam is taped.

2. Water management details should specify that flashing around the perimeter of the window must tie 

into a water-resistive barrier regardless of the approach taken.

3. Ensure that foam sheathing does not bear the weight of the window. The weight of the window should 

be supported by the wall frame.

Interior Ledge Window Installations:

STEP 1 Rough in window openings, 

oversizing by 1 1⁄2 inches in both 

dimensions.

STEP 2 Line rough opening with a 

frame made of plywood strips 3⁄4” thick 

by wall dimension + width of foam (the 

plywood should be flush on the interior 

surface and extend to the anticipated

outside face of the foam).

STEP 3 Install the exterior foam. 

The outer face of the foam should 

be flush with the outer edge of the 

plywood frame.

Continued on following page

14.35

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.35
Sources & Additional Information

Building Science Corporation. 2007. Guide to Insulating Sheathing, Building Science Corporation, 

www.buildingscience.com/documents/guides-and-manuals/gm-guide-insulating-sheathing 

Interior Ledge Window Installations - Continued

STEP 4 Install housewrap. 

Cut modified “I” over window.

STEP 7 Install window; 

plumb, level, and square as per 

manufacturer’s instructions.

STEP 8 Install jamb flashing first; 

install a drip cap (if applicable); 

install head flashing.

STEP 5 Fold in housewrap at jambs 

and sill. Fold back temporarily at jamb. 

Install backdam on sill.

STEP 9 Fold down head housewrap; 

apply corner patches at head; air seal 

window around the entire perimeter on the 

interior with sealant or non-expanding foam.

STEP 10 Install vertical wood 

strapping on top of the foam and 

housewrap to use when attaching siding.

STEP 6 Install adhesive-backed sill 

flashing and corner flashing patches at 

sill. Apply sealant at jambs, head, and sill.

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.36 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
STEP 1 Install OSB and 

housewrap on wood frame wall. 

STEP 4 Install adhesive-backed 

sill flashing and corner flashing 

patches at sill.

STEP 7 Install jamb flashing first; 

install a drip cap (if applicable); 

install head flashing.

STEP 2 Cut modified “I” in housewrap

STEP 5 Apply sealant at jambs, 

head, and sill.

STEP 8 Fold down head housewrap.

STEP 3 Fold housewrap in at jambs 

and sill. Temporarily fold up housewrap 

at head. Install backdam.

STEP 6 Install window; plumb, 

level, and square as per manufacturer’s 

instructions.

STEP 9 Apply corner patches at 

head; air seal window around entire 

perimeter on the interior with sealant 

or non-expanding foam; install foam 

sheathing over housewrap.

Exterior Ledge Window Installations:

14.37

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CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.38 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Duct Location – Dropped Ceiling Soffit

Ducts can be placed in a dropped ceiling soffit to keep them in conditioned space.

STEP 1 Use Manual J to determine appropriate HVAC size.

STEP 2 Design duct layout plan emphasizing compact layout with inside wall throws and air handler located 

in conditioned space. For cost savings consider using transoms over doors and one central return instead of 

ducted returns.

STEP 3 Hold meeting at home site after dry-in with designer, HVAC installer, framer, sheetrocker, other pertinent 

trades to discuss approach, if this is a new method.

STEP 4 Install sheetrock above chase. One method is to keep top plate of non-load bearing interior walls 3⁄4 inch 

from bottom cord of roof trusses. Slip drywall in this space.

14.39

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.39
STEP 5 Fabricate and seal ducts on the ground. Use hard ducts wherever possible. Fabricate a duct board box 

affixed to trunk line to serve as supply boot.

Supply boot comes directly from main trunk, as shown in “improved method” rather than connecting boot to 

trunk with a length of flex duct, as shown in original method. Thus duct chase can be narrower. 

Hard Duct

Hard ductwork is used wherever possible.

Flex Duct

Original method Improved method After framing

STEP 7 Install sheetrock around 

ducts to form chase, when sheetrocking 

the rest of the house (this is the second 

visit for sheetrockers).

Ducts are enclosed in soffits that add 

architectural interest to finished rooms.

STEP 6 Hang duct from the drywall 

using 2” nylon strapping material.

STEP 8 Install air handler in 

conditioned space in interior closet 

with large return air grill located 

over air handler. Use transoms over 

bedroom doors for return air path.

Air handler is located in the home in a 

closet with return grill above. Transoms 

over interior doors provide a return

 air path.

Fonorow, Ken, Dave Jenkins, Stephanie Thomas-Rees, and Subrato Chandra. 2010. 

“Low-Cost Interior Duct Systems for High-Performance Homes in Hot Climates,” 

Proceedings of the 2010 ACEEE Summer Study on Energy Efficiency in Buildings, 

Pacific Grove, CA, http://www.aceee.org/conf/10ss/index.htm

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.40 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Duct Location – In Open Web Floor Trusses Between Floors

Ducts can be placed in open web trusses between floors to keep them in conditioned space.

Rim joists must be thoroughly air sealed.

14.41

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CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.42 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Air Handler and Duct Sealing

Mastic or caulk 

Mastic 

Collar with strap; 

mastic on take-off 

Mastic or caulk Filter Rack 

Mastic to seal 

refrigerant and 

condensate line 

Mastic 

Mastic 

Mastic 

Mastic all corners 

of metal plenums 

Mastic plenum 

to air handler 

Mastic exterior of collars 

Mastic or tape 

exterior of duct board 

RETURN 

SUPPLY 

Mastic collars to 

metal plenum on 

inside or outside 

Never puncture inner liner. If repair is 

needed, install a coupling and seal properly.

Strap inner liner and

outer insulation

Use wide straps to support flex duct

spaced at 5-foot intervals

Run lines straight

using metal elbows at

bends and corners

Mastic 

boot seams

Mastic before 

attaching flex 

duct

REGISTER

Seal

joints

in boots

Seal boots to sheet goods (drywall/subfloor) 

with caulk, mastic, or spray foam. 

Aluminum-backed butyl tape seal to 

drywall for ceiling and sidewall registers.

Seal metal or flex to boot or elbow 

and joints in elbow with mastic.

AIR HANDLER

FLEX DUCT

SUPPLY AND RETURN PLENUMS

BOOTS

Mastic is a gooey adhesive that is applied wet. It fills gaps and dries to a soft solid. Mastics may or may not contain reinforcing 

fibers, and they may be used with reinforcing mesh tape.

14.43

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.43
(THIS PAGE INTENTIONALLY LEFT BLANK)

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.44 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Ductless Heat Pump Installers Guide

(Source: Northwest Energy Efficency Alliance Ductless Heat Pump Project, www.nwductless.com)

Best Practices for

Ductless Heat Pump

Installations A Contractor’s Guide

A quality ductless heat pump installation results from attention to details including: tools, 

installation and homeowner education. This guide provides information and suggestions to 

help you achieve successful ductless heat pump installations. Quality installations result 

in minimal call backs, more customer referrals, and increased awareness of ductless heat 

pump technology.

Installation Best Practices 

•	Follow	manufacturers’	installation	instructions.	This	guide	is	not	intended	to	replace	manufacturers’	specifications.

Outdoor Unit (Compressor):

•	Set	the	unit	on	a	stable,	level	surface.	

•		Risers	are	essential	to	prevent	snow	and	debris	build-up	and	should	be	installed	to	

allow	better	drainage	of	defrost	water.

•		Outdoor	units	should	be	secured	to	the	pad,	risers,	and/or	surface	on	which	they	

are	set	using	bolts	and/or	adhesive.

Refrigerant Tubing:

•	Factory	tubing	flares	and	fittings	are	NOT	TO	BE	REUSED.	

•	Create	new	flares	using	appropriate	R410A	flaring	tool	&	measurement	gauge.

•	Apply	refrigerant	oil	to	the	end	of	each	flare.

•	Connect	tubing	with	R410A	nuts	(supplied	with	indoor	and	outdoor	units)	using	

a	torque	wrench	tightened	to	manufacturer’s	specifications.

Refrigerant Charge:

•	Adjust	refrigerant	charge	ONLY	IF	NECESSARY.	Most	installations	do	not	require	

adjustment	from	pre-charge	levels.	

•	Gauges	are	not	needed	to	verify	refrigerant	levels.	(A	scale	should	be	used	

when	adding	or	removing	refrigerant.)

•		Consult the manufacturer’s installation manual to verify refrigerant protocols, specifications can often change.

Line Set Insulation and Protection

•		Insulation	must	cover	entire	line	set	length	to	avoid	condensation	and	decreased	

efficiency.	

•		Once	insulated,	protect	the	outdoor	portion	of	line	set	with	rigid	line	hide	to	avoid	

premature	degradation	damage	to	the	insulation.

•		All penetrations through the shell of the home must be sealed with an insulative sealant.

Condensate Drain:

•	Must slope downhill and can be routed with line set or run to	a	different termination point.

Improper Flaring

Inclined Surface

damaged

Cracked Uneven

thickness

Make sure proper

flare nut is fitted

Inner surface

must be

flaw-free

Smooth

all around

Refrigerant Tube

Required Tools

R410A	

Gauge	and	

Hose	Set

R410A	

Specific	

Flaring	

Tools	

Torque	

Wrench

Programmable

Refrigerant

Charging

Scale	

14.45

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.45
Disclaimer: This document is only to be used as a general guide for providing quality installations. For complete information regarding installation 

requirements, features, benefits, operation, and maintenance, review the manufacturer’s installation manual of the product being installed. 

Images of specific manufacturer product lines are not placed as endorsements, nor does this guide guarantee their quality.

Well Installed Outdoor and Indoor Unit = Happy Homeowner

Anchor	Foot	to	Riser	

Indoor	Unit	is	Installed	High	on	Wall	

Indoor	Unit	is	Level

Indoor	Unit	is	Centrally	Located	in	Home	

for	Best	Air	Circulation	

Rigid	Line	Hide

Adhesive

Riser	Block	

Wall	

Penetrations

Sealed	With	

Insulative	

Sealant

Pad	 Compacted	Ground		

An initiative of the Northwest Energy Efficiency Alliance, an alliance of NW Utilities and energy efficiency partners. 

Homeowner Education

•		Ensure	homeowner	has	a	copy	of	the	Manufacturers	Operation	Manual	that	is	

provided	with	the	indoor	unit.	Refer	to	this	manual	as	you	perform	a	walkthrough	

of	unit	operation.

•		Provide	homeowner	with	a	copy	of	the	“Homeowner’s	Guide”	and	remind	

homeowners	of	www.GoingDuctless.com	for	more	information	about	ductless	

heating	and	cooling	systems.

•	Educated	homeowners	reduce	call	backs	and	promote	your	services!

Contractor Resources

•	For	information	on	becoming	a	Project-oriented	contractor,	visit	www.NWDuctless.com	or	call	(503)	808-9003.	

Project-oriented	contractors	are	eligible	to	perform	installations	that	receive	utility	rebates	of	up	to	$1,500!

Ductless Heat Pump Installers Guide, Continued

(Source: Northwest Energy Efficency Alliance Ductless Heat Pump Project, www.nwductless.com)

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.46 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Roof Fascia/Soffit Vent Detail

The soffit detail for vented attics discourages water draining off the roof from coming into the soffit vent openings. The 

detail was designed by Building America’s Consortium for Advanced Residential Buildings (CARB) team (led by Steven 

Winter Associates) for Mercedes Homes of Melbourne, Florida, 

Aluminum wrap over 2x4 fascia

Continuously perforated 

vinyl soffit

Textured cement finish to top 

of concrete wall

Figure 1. 

The typical soffit design for new home 

construction in Florida is susceptible to 

water intrusion from direct wind pressure, 

suction on the lee-ward side of the house, 

and from surface tension as the water 

sheets off the roof and clings to the fascia 

and soffit. 

Figure 2. 

The fascia was redesigned to extend 1 inch 

below the soffit to form a drip edge, directing 

water down and away from the house. A 

perforated soffit board product with recessed 

rather than surface openings was installed 

to limit water intrusion while encouraging 

greater air circulation and faster drying within 

the eave assembly The improved eave design 

has a fascia that is extended one inch below 

the soffit to form a drip-edge to defeat the 

rain water’s surface tension. The vented soffit 

is reconfigured with recessed perforations 

arranged along the top of perpendicular 

ridges. Additional blocking is also installed to 

prevent soffit blow-out. 

Aluminum wrap over 2x6 fascia

Vinyl soffit with recessed 

perforations

Textured cement finish to top 

of concrete wall

14.47

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.47
Sources & Additional Information

Zoeller, William. 2006. “Designing and Building Hurricane-Resistant Homes,” prepared by Steven Winter Associates, published in Home 

Energy Magazine, Fall 2006, www.carb-swa.com/articles/in%20the%20news/HomeEnergy_Designing%20and%20Building%20Hurricane%20

Resistant%20Homes.pdf.)

Detail of old soffit showing bottom of 

assembly is flat with vent perforations 

facing downward.

Detail of new soffit design showing 

extended fascia, providing drip edge.

Detail of new soffit design showing fascia 

and recessed vent perforations.

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.48 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Ice Dam Prevention

Ice dams are hazardous for buildings and people. Use the following guidance to minimize 

chances of ice dams forming on your homes.

Ice Dam Formation - 

Ice dams can form when the roof deck 

temperature is above freezing and the 

air is below freezing. 

Melted snow eventually reaches the 

colder edge of the roof where it refreezes, 

creating an ice dam that collects more 

water and ice. The ice dam is often 

not visible under the snow layer on the 

roof except for the telltale icicles, which 

indicate melting is occurring somewhere 

on the roof.

(Source Lstiburek 2011, 

Building Science Corporation)

Three Steps to Ice Dam Control 

in a Vented Attic – 

1) Construct an airtight ceiling plane. Limit 

the number of holes through the ceiling and 

air seal every one. 

2) Insulate well, especially over the top 

plates, use raised heel trusses if needed to 

get full insulation coverage. 

3) Vent the underside of the roof deck, 

with vent screens at every rafter bay and a 

2-inch airspace under the sheathing where 

ground snow loads are greater than 30 lb/ft2

. 

(Source Lstiburek 2011, 

Building Science Corporation)

Thin ice slab under snow

Snow

Melt water running 

under thin ice slab

Melt water running 

down underside 

of sheathing

Ice dam

Ice

Icicles

Continuous ridge 

ventilation

Attic Ventilation

Roof insulation

Insulation wind baffle

2" minimum spacing

Water 

protection 

membrane

Continuous 

soffit vent

Caulking or sealant

Consider increasing depth of 

insulation by using deeper trusses or 

oversized (longer) trusses

14.49

CHAPTER 14. FIELD GUIDES FOR INSTALLERS

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 14.49
Sources & Additional Information

Lstiburek, Joseph. 2011. Dam Ice Dam, Insight 046, Feb. 2011, Building Science Corporation, 

www.buildingscience.com/documents/insights/bsi-046-dam-ice-dam/

Ice Dam Control in an Unvented 

Attic with Insulation above 

Roof Deck –

Cover roof sheathing with a fully adhered 

air barrier membrane. Install two layers (to 

R-50 or greater) of rigid insulation over air 

barrier, stagger the seams. Note there is 

no vented space under the roof cladding 

to compensate for the insulation value of 

the snow layer. This roof should be used 

where the ground snow load is less than 

50 lb/ft2. With ground snow loads greater 

than 50 lb/ft2, provide a ventilation space 

under the roof cladding as shown in 

Figure 4 (Source Lstiburek 2011, Building 

Science Corporation).

Ice Dam Control in an Unvented 

Attic with Insulation above Roof 

Deck in High-Snow-Load Areas – 

In regions with snow loads greater than 

50 lb/ft2, the snow can provide enough 

thermal resistance to allow the roof 

cladding to be above freezing even when 

the air temperature is below freezing (one 

foot of snow = R-10 to R-15). To prevent ice 

damming with an unvented attic in these 

conditions, construct a “vented over-roof” 

over the top of the “unvented compact 

roof” as shown above (Source Lstiburek 

2011, Building Science Corporation).

Shingles Roofing paper

Wood decking

Timber rafter or exposed joist

Minimum, R-50 rigid insulation in 

two or more layers with horizontal 

and vertical joints staggered

Nail base for shingles (plywood or OSB)

screwed through rigid insulation to wood 

decking or timber rafters

Air barrier membrane

Roof sheathing

Roof sheathing

Vented space

Vented 

fascia Timber rafter or 

exposed joist

Wood decking

Air barrier membrane

Spray foam 

air seal

Roofing membrane

Shingles

Roofing paper

R-60 rigid insulation

 (horizontal and vertical 

joints staggered)

CHAPTER 14 / BUILDING AMERICA BEST PRACTICES SERIES

14.50 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Several builders are building energy-efficient homes in the mixed-humid climate. The following case studies 

showcase four mixed-humid climate builders who have worked with Building America research teams to build 

homes that exceeded the Building America benchmark by 40% or more. The energy-efficient measures they 

incorporated in their homes are summarized in the table below.

Table 1. Summary of Energy-Efficient Measures Incorporated in Case Study Homes 

in the Mixed-Humid Climate

Measure

Insight Homes 

Seaford, DE

Tindall Homes 

Princeton, NJ

Urbane Homes 

Crestwood, KY

Pine Mountain Builders 

Pine Mountain, GA

Project 54 homes at Deep 

Creek in Seaford, DE, 

at Windstone in Milton, 

DE; and at Ridings of 

Rehoboth in Lewes, DE. 

1,400 to 3,300 ft2

20 homes in The Legends 

at Mansfield, Columbus, 

NJ. 3,800 to 6,000 ft2

10 homes in first 

community, plus 5/year 

since, Louisville, KY. 

1,484 to 2,996 ft2

Approximately 14 in 

Callaway Gardens’ 

Longleaf Community in 

Pine Mountain, GA. 

1,929 ft2 to 3,124 ft2

HERS 50-56 58 57-62 59-85

Walls Advanced 2 x 6 framing at 

24-inches on center

Advanced 2 x 6 framing at 

24 inches on-center

Advanced 2 x 6 at 24-inch 

on center framing

2x4 16-inch on-center 

framing

Wall 

Insulation

Dense-packed netted and 

blown-in fiberglass to R-23

R-18 polyurethane 

spray foam; R-12.5 foam 

insulated foundation walls

R-5 XPS foam sheathing 

with R-19 fiberglass batts

R-3 XPS foam sheathing

R-13 low-density spray foam

Attic 

Insulation

R-38 with loose-blown 

fiberglass

Vented R-49 with R-30 

kraft-faced fiberglass 

batts and R-19 blown-in 

cellulose 

R-50 blown fiberglass R-30 low-density spray 

foam

Radiant 

Barrier

No No No No

Ducts In sealed conditioned 

crawlspace. R-6 insulated 

flexible branches

In open web floor joists in 

conditioned space

In sealed conditioned 

space

In sealed semiconditioned space. 

Mastic sealed

40% Whole-House Energy Savings 

in the Mixed-Humid Climate

Case Studies

CS.1

BUILDING AMERICA BEST PRACTICES SERIES / CASE STUDIES

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 CS.1
Measure

Insight Homes 

Seaford, DE

Tindall Homes 

Princeton, NJ

Urbane Homes 

Crestwood, KY

Pine Mountain Builders 

Pine Mountain, GA

Air Handler Within main living space Largest unit in basement. 

Secondary unit in living 

space on second floor

Within main living space Within sealed attic

Air Sealing 3.0 ACH at 50 Pa. 1.5 ACH at 50 Pa. 3.6 ACH at 50 Pa. 1.8 ACH at 50 Pa.

HVAC Right-sized 16 SEER air 

conditioner; 96% AFUE 

gas furnace 

Right-sized 13.5 SEER 

air-conditioner; two 92% 

AFUE gas furnaces. 

Four independent 

temperature zones

Right-sized 14.5 SEER/8.4 

HSPF heat pump

Right-sized 14 SEER/8.0 

HSPF heat pump; some 

homes have groundsource heat pump

Windows Vinyl-framed, doubleglazed, low-e, argon-filled; 

U=0.26, SHGC=0.19

U=0.16, SHGC=0.61 Vinyl-framed, doubleglazed, low-e, argon filled; 

U=0.32, SHGC=0.31

Wood-framed, doubleglazed windows, argon 

filled; U=0.38, SHGC=0.35

Water 

Heating

0.87 EF tankless gas water 

heater 

Tankless gas water heater 0.92 EF electric tank water 

heater

0.93 EF electric 40 gallon 

tank heater

Ventilation Integrated exhaust fans 

with run time to satisfy 

ASHRAE 62.2

Heat recovery ventilator 

(HRV) connected to the 

return plenum on both 

furnaces

Fresh air intake with 

damper timed to exhaust 

ventilation 

Fresh-air ducted to air 

cycler

Moisture 

Management 

Features

Conditioned crawlspace 

has R-10 continuous 

XPS on the interior of 

the walls; two layers of 

poly sheeting, taped and 

sealed at all penetrations 

and to the foundation 

floor and walls

A drainage plane layer is 

used over insulating foam 

sheathing and is correctly 

integrated with flashing 

which was properly 

applied around windows 

and door areas to promote 

shedding of water

XPS rigid foam board for 

sheathing on walls and 

concrete

R-13 closed-cell with 

spray polyurethane 

foam insulation, R-3 XPS 

insulation

Green 

features

Low-or-no VOC paints and 

flooring 

 Open-web floor joists 

use less lumber than solid 

joists

Low-or-no VOC paints 

and flooring 

Mature trees. Low- or 

no-VOC paints, flooring. 

Low-flow plumbing 

fixtures. Erosion control 

and on-site recycling 

during construction

Lighting and 

Appliances 

100% hardwired CFL 100% CFL, ENERGY STAR 

appliances

100% hardwired CFL, 

ENERGY STAR appliances

75% CFL, ENERGY STAR 

appliances

Solar No Optional upgrade; 2.64-

kW photovoltaic system 

on garden shed roofs

No No

Verify All homes third-party 

tested and inspected. 

ENERGY STAR 

certifications

All homes third-party 

tested

All homes third-party 

tested and inspected. 

ENERGY STAR 

certifications

All homes third-party 

tested and inspected. 

Builders Challenge, 

EarthCraft House 

and ENERGY STAR 

certifications

CASE STUDIES / BUILDING AMERICA BEST PRACTICES SERIES

CS.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
BUILDER PROFILE

Builder: Insight Homes

Contact: Rob Lisle, President 

(302) 337-0400 (main office)

www.itsjustabetterhouse.com

Founded: 2007

Where: Bridgeville, DE

Employees: 8 to 14

Number of homes per year: 40 to 70 

Development: 

Deep Creek, Seaford, DE 

Windstone, Milton, DE 

Ridings of Rehoboth, Lewes, DE

Size: 1,400 to 3,300 ft2, 3 to 4 bedrooms, 

2 to 3.5 baths

Price Range: $220,000 to $280,000

Rob Lisle, a businessman who owns multiple companies in Delaware, 

initially founded Insight Homes in 2007 as an experimental company. 

His goal was to build 36 identical houses, three at a time. Energy 

efficiency would improve with each generation while the sales price 

remained the same as a comparable home in Delaware.

“After experimenting with seven generations of a single home plan we 

were able to achieve our goal of a HERS score of 56,” said Lisle. To 

further refine his building specifications, Lisle began working with the 

U.S. Department of Energy’s Building America program.

Lisle worked with Integrated Building and Construction Solutions 

(IBACOS), a Building America research partner, to evaluate building 

durability and bulk water management details. IBACOS also helped 

develop duct designs and system layouts for several of Insight Homes’ 

models to address recurring comfort issues with the heating, ventilation, 

and air conditioning system (HVAC). IBACOS continues to work with 

Insight Homes to establish quality assurance measures that will help the 

company consistently deliver high-quality production houses as they 

build homes in greater volume.

While Insight Homes has been in business for just four years, the 

company’s increasing number of home sales indicates that offering 

energy-efficient homes at the same cost as any comparable home in the 

Delaware area is a good way to beat a down market. In addition, Insight 

markets their homes exclusively based on their energy efficiency rather 

than the great locations or design. They advertise their homes as “the 

top 1% in the nation for energy efficiency” with an average monthly 

power bill of $92.68 for the years 2009 to 2010.

BUILDING TECHNOLOGIES PROGRAM

Insight Homes’ Jerry model showed that 

the builder’s standard specification package 

exceeds the 40% level of energy savings 

relative to the Building America benchmark, 

achieving 50% energy savings and a HERS 

index score of 50. The 2,140 ft2 home sells for 

around $196,000.

Building America Best Practices Series

Volume 16. 40% Whole-House Energy Savings in the 

Mixed-Humid Climate

Case Study:

Insight Homes

Deep Creek | Seaford, DE

R
One of Insight Homes’ volume projects is a 30-home community 

called Deep Creek in Seaford, DE. The Deep Creek homes achieved 

50% whole house energy savings compared to the Building America 

benchmark (a home built to the 1993 Model Energy Code). The Jerry 

model has a HERS score of 50. 

Insight Homes is now building 40 to 70 homes per year. They range in 

size from 1,400 to 3,300 ft2, at a price range of $220,000 to $280,000.

Lisle is a frequent speaker at building conferences on the topic of energy 

efficiency. In 2009, he began hosting a local weekly radio show where he 

answers callers’ questions about green and energy-efficient building.

“Our company’s mission is to develop systems and approaches that 

demonstrate to other builders how they can also build energy-efficient, 

healthy, and durable homes at cost-competitive prices,” said Lisle.

Energy-Efficiency Features

All Insight Homes are built using the energy-efficiency package that 

Lisle developed through his experimental home building and the 

refinements developed with IBACOS.

Insight Homes’ standard energy-efficiency features start with a 

conditioned crawlspace insulated with continuous R-10 extruded 

polystyrene rigid foam (XPS) on the interior of the walls. 

Insight achieves airtight construction and an improved thermal envelope 

with advanced 2 x 6 framing at 24-inches on center. Walls are insulated 

with dense-packed netted and blown-in fiberglass to R-23. The attic is 

insulated to R-38 with loose-blown fiberglass. Blower door tests show a 

maximum of 3.0 air changes per hour at 50 Pascals of pressure.

The high-efficiency HVAC system includes a 96% AFUE two-stage 

propane-fired furnace and a 16 SEER air conditioner. The ducts are 

located in the sealed, conditioned crawlspace and consist of a sheet 

metal trunk and R-6 insulated flex duct branches. There are two central 

returns for the main living space with door undercuts at enclosed rooms. 

The duct blaster test shows less than 3% total system leakage and less 

than 1% leakage to the exterior. 

Integrated bathroom exhaust fans coordinate run time to satisfy 

ASHRAE 62.2 ventilation requirements. Insight Homes explored several 

whole-house ventilation strategies before settling on an exhaust-only 

system. The previous supply strategies required the use of a filter to 

limit the influx of particles in incoming air. Homeowners who were not 

replacing the filters according to schedule complained of performance 

issues. Insight Homes made an effort to teach homeowners the 

importance of replacing filters during new homeowner orientations, but 

the problem persisted. 

The HERS Index scores for Insight Homes 

are significantly lower than the new codebuilt homes. They range from 49 to 56, 

depending on the model.

(Top) The above-grade walls are 

constructed with 2”x6” wood framing 

spaced 24” on center, providing space for 

R-23 of dense-pact blown fiberglass. 

(Bottom) Insight Homes are built with 

raised-heel energy trusses, which can 

accommodate a full 14 inches of insulation 

over the whole ceiling deck including the 

top plate, eliminating cold spots along the 

tops of outside walls. 

c

Insulation at full thickness 

over exterior walls

Raised Heel or 

Insulation Energy Truss

BUILDING AMERICA BEST PRACTICES SERIES

2
The 0.87 EF tankless gas water heater uses a homerun distribution 

system, which uses a multiport manifold to deliver water to each fixture 

through PEX tubing. 

The low-e windows are vinyl-framed, double-glazed, and argon-filled, 

with a U value of 0.26 and an SHGC of 0.19. Flashing tape is used 

to keep out any air and moisture that gets past the house wrap. Rain 

troughs built into the window sills are a further precaution.

Lighting is a combination of screw-in and hardwired compact 

fluorescent lighting.

Insight Homes has a third party perform blower door, duct blaster, and 

flow hood tests on 100% of its homes. Each home is ENERGY STAR®-

certified and subject to additional third-party inspections. 

Innovation

Insight Homes is currently working with IBACOS to build and test 

two side-by-side houses—one with Insight’s standard energy-efficiency 

features and the other with an advanced HVAC system that includes a 

super-efficient heat pump paired with a tankless water heater that can 

provide backup heating. 

“This system does not exist anywhere else in the market,” said Kevin 

Brozyna, an IBACOS researcher. “We are working with Rob Lisle and 

manufacturers to develop it as a new product.” 

Health, Durability, Sustainability

Insight Homes uses poured concrete wall foundations with an 

asphalt-based coating to ensure that the crawlspace stays moisture 

free. The earthen floor of the crawlspace is covered in two layers of poly 

sheeting, taped and sealed at all penetrations and to the foundation 

walls. French drains are used to further keep the foundation dry. 

Downspouts for the gutters are located at the front of the house and 

piping attached to the downspouts is buried underneath the sidewalks, 

carrying rain water away from the house and releasing it into the yard, 

far away from the foundation.

All Insight Homes meet the strict requirements of the American Lung 

Association Healthy House program, which include a whole-house 

dehumidifier and central vacuum system.

All Insight Homes achieve not only ENERGY STAR certification but 

also qualify for ENERGY STAR’s Indoor Air Package.

The poured concrete wall foundation is 

coated with an asphalt-based moisture 

blocker. The conditioned crawlspace has 

R-10 XPS insulation continuous on the 

interior of the walls, and the earthen floor 

is covered with two layers of polyethylene 

sheeting that is taped and sealed at all 

penetrations and to the foundation walls.

Insight Homes uses a dense-pack 

insulation system that blows loose, dry, 

formaldehyde-free fiberglass into the walls 

and attics, eliminating gaps around wiring 

and fixtures. When the insulation is in 

place, the fibers adhere to each other to 

form dense insulation. 

3

CASE STUDY: INSIGHT HOMES
Dollars and Sense

The representative model for this case study, the 2,140 ft2 Jerry, has 

3 bedrooms and 2.5 baths. IBACOS analysis showed that the Jerry 

model uses 50% less energy than the Building America benchmark. The 

builder estimates that energy-efficiency upgrades cost $7,660 per house, 

which adds $612 a year to a mortgage (based on a 30-year term and 

7% interest). But the homeowner enjoys an estimated $1,405 a year in 

energy savings, for a net annual gain of $793. 

Table 1. Added Costs and Savings of Energy-Efficient 

Measures for Insight Homes

Total Energy Savings* 50%

Total Added Builder Costs** $7,660 

Annual Mortgage Payment Increase*** $611.55 

Annual Utility Savings $1,405 

Annual Net Cash Flow to the Homeowner $793.45 

* For the Jerry model compared to the Building America benchmark.

** Costs are based on builder estimates, and manufacturers’ data, plus a 10% markup relative to 

minimum code. These costs do not reflect rebates, incentives, and subsidies.

***The annual mortgage payment is an estimate based on a 30-year mortgage with a 7% fixed 

interest rate.

The Bottom Line

One of the keys to Insight Homes’ success was their willingness to 

experiment with various combinations of system solutions until they 

developed a cost-effective, energy-efficient, and replicable specifications 

package. Insight’s standard home is capable of achieving better 

than 40% source energy savings, compared to the Building America 

benchmark.

Marketing homes exclusively on the basis of energy efficiency has paid 

off in Insight’s home sales.

“This may not work for all builders, but it seems to be working well for 

Insight,” said IBACOS researcher Brozyna.

In 2008 and 2009, Insight had 38 closings on homes at Deep Creek as 

well as other communities in Sussex County, DE. They sold 54 homes 

in 2010 and expect to finish building and selling 70 homes by the end of 

2011. Insight Homes also has a long backlog of orders for new houses 

that promises to keep their sales numbers growing. 

IBACOS has continued its partnership with Insight Homes to research 

new energy-efficiency technologies and support development of its 

business processes and practices.

For More Information

www.buildingamerica.gov 

EERE Information Center 

1-877-EERE-INF (1-877-337-3463) 

eere.energy.gov/informationcenter

PNNL-SA-83151 September 2011

Key Features 

•	 Average HERS score: 50

•	 Basement: Interior of walls insulated

with R-10 XPS

•	 Crawlspace: Unvented earthen

floor covered in two layers of poly 

sheeting, taped and sealed at all 

penetrations and to foundation walls

•	 Advanced framing: 2x6,

24-inch on-center walls 

•	 Wall insulation: R-23 dense-packed

netted and blown-in fiberglass 

•	 Windows: Vinyl-framed, doubleglazed, low-e, argon-filled; 

U=0.26, SHGC=0.19

•	 Attic: R-38 loose-fill fiberglass

•	 Blower door test: 13.0 ACH50

•	 Ventilation: Integrated exhaust fans

with run time to satisfy ASHRAE 62.2

•	 96% AFUE two-stage propane-fired

furnace

•	 16 SEER split system air-conditioning

unit

•	 All-metal ducts within conditioned

space

•	 Duct blaster test: 3% total leakage

•	 Tankless gas water heater

•	 100% screw-in and hardwired CFL

BUILDING AMERICA BEST PRACTICES SERIES

4
Swedish native Mark Bergman launched Tindall Homes in Columbus, 

New Jersey, in 1986 with a mission to build homes with greater 

durability and energy efficiency than other houses on the market. 

Bergman found an ally in Integrated Building and Construction 

Solutions (IBACOS), a research team in the U.S. Department of 

Energy’s Building America program. With design analysis and advice 

from IBACOS, Bergman built 20 luxury homes at The Legends at 

Mansfield community in Columbus, New Jersey. These homes use 

40% to 49% less energy than a code-built home and achieve an average 

HERS score of 58. (A typical new American home has a score of 

100—lower scores indicate greater energy efficiency). For the buyers 

of Tindall Homes’ Morgan design, for example, this translates into 

calculated annual energy savings of $1,541. With the addition of a solar 

photovoltaic system, the energy efficiency increases another 5% to 8%.

“Over their lifetimes,” Bergman predicted, “our houses will save more in 

energy costs than the purchase price.” Bergman said greater durability is 

another benefit of applying Building America recommendations.

Energy-Efficiency Features

Tindall Homes targeted move-up homebuyers in the luxury housing 

market by offering large floor plans with two-story spaces and high-end 

finishes. During the design phase of The Legends of Mansfield houses, 

IBACOS recommended several above-code options that would work 

together to create a high-performance home. These included advanced 

BUILDING TECHNOLOGIES PROGRAM

Tindall Homes’ energy-efficient Morgan 

model in The Legends at Mansfield 

community uses 49% less energy than the 

Building America benchmark (2008).

Building America Best Practices Series

Volume 16. 40% Whole-House Energy Savings in the 

Mixed-Humid Climate

Case Study: 

Tindall Homes

The Legends at Mansfield | Columbus, NJ

BUILDER PROFILE

Builder: Tindall Homes

Contact: Mark Bergman (former owner, 

the company has been sold) 

Founded: 1986

Where: Princeton, New Jersey

Employees: 10

Number of homes per year: 20 to 30

Development: Legends at Mansfield, 

Columbus, New Jersey

Size: 20 homes, 3,800 to 6,000 ft2, 

4 to 5 bedrooms, 3 to 4.5 baths

Price Range: $700,000 to $900,000

R
wood framing, spray foam wall insulation, precast insulated foundation 

walls, increased attic insulation, a heat recovery ventilator, a tankless gas 

water heater, and energy-efficient HVAC and lighting.

Advanced framing conserves lumber and provides more space for 

insulation. By upgrading from the 2" x 4" conventional stud walls 

located 16" on center to 2" x 6" studs placed 24" on center, the builder 

was able to significantly decrease conductive heat loss through exterior 

walls. Three inches of closed-cell polyurethane spray foam within 

the walls increased the insulation to R-18, sealed penetrations, and 

improved air tightness. 

The precast concrete foundation system with integral R-12.5 insulation 

board within the wall cavity provides an airtight basement and a more 

comfortable home year-round than a traditional block or site-poured 

concrete foundation. 

The builder insulated the vented attic to R-49 with a combination 

of R-30 kraft-faced fiberglass batts and R-19 blown cellulose. The 

overhanging floors contain 2" of urethane foam (R-12) and R-30 kraftfaced fiberglass batts to equal R-42.

A direct-vent tankless gas water heater provides hot water instantly as 

needed, which is more energy-efficient than continuously heating a large 

tank of water.

Since IBACOS’ recommendations reduced the houses’ energy needs, 

Tindall Homes was able to reduce the size of the heating and cooling 

equipment. The two optimally sized 92% AFUE direct vent natural gas 

furnaces and two 13.5 SEER air conditioners are of smaller capacity 

than standard, reducing the cost to the builder by $800 and contributing 

additional energy savings for the homeowner. Due to the large size of 

the homes, one HVAC unit was located in the conditioned basement and 

the other was placed on the second floor. There are four thermostats in 

the homes that control the temperature for four independent zones. This 

Tindall Homes installed their optional grid-tied solar photovoltaic systems on backyard garden sheds, situated for maximum solar gain. 

Wiring for the systems runs underground from the shed to the home’s basement.

Insulated precast concrete foundation 

walls, spray foam-filled frame walls, and 

R-49 of attic insulation keep the Tindall 

homes in Columbus, New Jersey, warm in 

winter and cool in summer.

BUILDING AMERICA BEST PRACTICES SERIES

2
option gives the homeowner more control of the comfort levels in the 

home, where needed, and provides opportunities to use less energy. All 

of the ductwork is located within conditioned space.

Innovation

Fourteen of the 20 Legends of Mansfield homes are equipped with a 

2.64-kilowatt solar photovoltaic (PV) system that is tied to the grid. 

Since some of the houses with solar systems could not be oriented for 

optimal solar collection, Tindall used an innovative solution. They built 

specially designed garden sheds in the back yards of those homes and 

mounted the PV panels on the shed roofs. The sheds have a short pitched 

roof in the front and a long, 40-degree sloped back roof oriented to the 

south for the PV panels. Wiring for the system runs underground from 

the shed to the house, and the inverter is in the basement. 

Health, Durability, Sustainability

To improve indoor air quality, Tindall Homes replaced the standard 

ventilation system with a heat recovery ventilator (HRV), connecting it 

to the return plenum on both furnaces. This upgrade provides a way to 

bring in fresh air and capture much of the heat contained in outgoing air 

before it exhausts to the outside. 

“Incoming air in the winter may be only 30 degrees. If you warm it 20 

degrees with exhaust air, then you are enjoying this heat virtually free,” 

said John Clark, construction supervisor for The Legends at Mansfield. 

The HRV system provides improved ventilation, better air quality, and 

enhanced occupant comfort.

Dollars and Sense

Tindall Homes had planned to build 39 houses in The Legends of 

Mansfield community, but due to the downturn in the market for 

luxury homes, only 20 houses were completed. The houses are twostory, single-family dwellings ranging in size from 3,800 to 6,000 ft2, 

with 3 to 5 bedrooms and 2.5 to 3.5 bathrooms. Prices ranged from 

$700,000 to $900,000. 

The representative model for this case study, the 4,700 ft2 Morgan, 

has 4 bedrooms and 3.5 baths. Analysis by IBACOS showed the 

Morgan model used 49.2% less energy than the 2008 Building America 

Benchmark without PV, and 55.9% less energy when PV is included. The 

energy efficiency upgrades (not including PV) cost nearly $18,000 per 

house, which adds $1,699 a year to a mortgage (based on a 30-year term 

and 7% interest). But the homeowner enjoys an estimated $3,240 a year 

in energy savings, for a net annual gain of $1,541. 

Key Features

•	 Basement insulation: Integral

R-12-5 insulation board

•	 Advanced framing, 2 x 6,

24-inch o.c. walls 

•	 Wall insulation: R-18 closed-cell

spray polyurethane insulation

•	 Windows: U-value=0.36, SHGC=0.33

•	 Attic: Vented, R-30 fiberglass batt

and R-19 blown cellulose insulation

•	 Blower door test: 3.2 ACH50

•	 Ventilation: 50 cfm heat

recovery ventilator

•	 Two 92% AFUE natural gas furnaces

•	 13.5 SEER air-conditioner

•	 Ducts in conditioned space

•	 Duct blaster test: <6% total leakage

•	 Two tankless gas water heaters,

85 EF

•	 95% CFLs

•	 2.64 kW grid-connected photovoltaic

system available

•	 Average HERS score: 58

3

CASE STUDY: TINDALL HOMES
Table 1. Added Costs and Savings of Energy-Efficiency 

Measures for Tindall Homes

Total Energy Savings* 49%

Total Added Builder Costs** $17,630

Annual Mortgage Payment Increase*** $1,699

Annual Utility Savings $3,240

Annual Net Cash Flow to the Homeowner $1,541

* Compared to the Building America benchmark.

** Costs are based on builder estimates and manufacturers’ data. These costs do not include 

solar photovoltaic systems and do not reflect rebates, incentives, and subsidies.

***The annual mortgage payment is an estimate calculated by CARB and is based on a 30-year 

mortgage with a 7% fixed interest rate.

The Bottom Line

“If all builders built to save 50% on energy use, we could make a big 

difference,” Bergman said. “We all want to make money, but at some 

point, as a society, we have to evaluate what we are doing. We take 

seriously our responsibility to the surrounding community, to the 

environment, and most importantly to our buyers.”

“It’s important to recognize that many of the things that make our 

houses more energy efficient will also make them last longer,” said 

Bergman, who noted that features like aggressive air sealing help keep 

out humidity and dampness. 

For More Information

www.buildingamerica.gov 

EERE Information Center 

1-877-EERE-INF (1-877-337-3463) 

eere.energy.gov/informationcenter

PNNL-SA-83152 September 2011

BUILDING AMERICA BEST PRACTICES SERIES

4
BUILDER PROFILE

Builder: Urbane Homes

Contact: Abe Gilbert 

and Zane Underwood, Co-Owners 

(502) 509-7373 

www.myurbanehome.com

Founded: 2007

Where: Louisville, KY

Employees: 2 to 3, not including 

subcontractors

Number of homes per year: 5 plus

Size: 1,484 to 6,000 ft2, 

3 to 5 bedrooms, 2 to 3.5 baths

Price Range: $150,000 to $450,000

When Abe Gilbert and Zane Underwood founded Urbane Homes in 

2007, their goal was to build bigger, better, and more affordable houses 

than any other builder in the area. They are now one of the top 10 

production home builders in Louisville.

At the time Gilbert and Underwood started Urbane, they could see the 

beginning of a downturn in the housing market and knew that their 

survival depended on building the most affordable houses in Kentucky. 

By working with the U.S. Department of Energy’s Building America 

program, they discovered how to make their houses not just affordable 

but energy efficient—their homes achieve HERS scores of 57 to 62. 

Gilbert says Urbane Homes sells every house they build, and they don’t 

do any formal advertising. 

“We just list the house about two weeks before it’s done so people can 

come and see it. The longest we’ve had a house listed is 3 weeks. The last 

one we sold was on the market for just 2 weeks.” 

As they launched Urbane Homes, Gilbert researched ways to reduce 

costs by making their building practices efficient. This led him to Steve 

Bazek, a Boston architect who pioneers in efficient and green housing 

designs. 

“Bazek said, ‘Why don’t you build really good homes that are also 

energy efficient and green?’” Gilbert remembers. He and Underwood 

were skeptical. How could they keep costs low while adding energyefficiency upgrades? But Bazek thought they could do both. 

Bazek worked with the builders to design their first house and 

introduced them to the National Association of Home Builders 

BUILDING TECHNOLOGIES PROGRAM

Urbane Homes won an Energy Value Housing 

Award in 2009 for their energy-efficient 

prototype. They built the house in 2008 for 

just $36 per ft2 using materials and techniques 

available to all builders and achieved an 

energy savings of 44% compared to the 

Building America benchmark. 

Building America Best Practices Series

Volume 16. 40% Whole-House Energy Savings in the 

Mixed-Humid Climate

Case Study:

Urbane Homes

Various Locations | Greater Louisville, KY

R
(NAHB) Research Center, a Building America research partner. The 

partnership helped them incorporate energy-efficient features and green 

building practices. The NAHB Research Center provided technical 

support for a frost-protected shallow foundation and for code approval 

of their prototype house.

“We set out to prove that we could build a really good house for an 

affordable price, and we built that first house for $36 per square foot,” said 

Gilbert. The remarkably low cost per square foot of Urbane’s prototype 

model was verified by both the NAHB and DOE. A typical home in 

Louisville costs between $55 and $85 per ft2 to build, not including the lot. 

Urbane Home’s prototype model won three major building awards 

in 2009, including two NAHB Energy Value Housing Awards (for 

affordability and production), and it was runner-up for the NAHB’s 

Green Project of the Year. 

By 2010, Urbane Homes built 10 production homes on custom lots in 

scattered locations within greater Louisville. Urbane’s six model home 

designs are one- and two-story, single-family dwellings ranging in size 

from 1,484 to 2,996 ft2, with 2 to 5 bedrooms and 2 to 3.5 bathrooms. 

Prices range from $150,000 to $450,000. 

The homes have calculated energy savings of 41% to 44% compared 

to the Building America benchmark (a home built to the 1993 Model 

Energy Code), and have HERS scores of 57-62, depending on the 

model. A typical new American home has a HERS score of 100 (lower 

scores indicate greater energy efficiency).

Energy-Efficiency Features

Urbane Homes worked with the NAHB Research Center to develop an 

energy-efficiency package using readily available off-the-shelf products. 

“We wanted to pick all the low-hanging fruit for green and energyefficient design and put it in a standard package that made sense and 

was affordable,” said Gilbert. 

Urbane’s standard package begins with the frost-protected shallow 

foundation. This method allows footing or foundation depth to be reduced 

from 48" to 12" to 16", saving about two-thirds the amount of concrete 

needed. Traditionally, foundations are protected from frost-heaving damage 

by placing the footing below the frost line, but the shallow foundation 

is protected from freezing by placing rigid insulation around the outside 

of the foundation. Urbane Homes uses 1" of R-5 extruded polystyrene 

(XPS) foam below the entire slab. The exterior foundation is protected by 2"

(R-10) of recycled expanded polystyrene (EPS) foam, and the interior slab 

edge is insulated with 11⁄4" (R-5) of EPS foam. 

The attic is insulated with R-50 blown fiberglass.

Urbane Homes worked with the 

researchers from the National Association 

of Home Builders, a Building America 

partner, to develop a frost-protected 

shallow foundation that can reduce the 

cost of excavation and amount of concrete 

needed. The bottom of the footings can 

be placed 12" to 16" below grade instead 

of digging below the frost line (up to 48") 

because the foundation is protected from 

freezing by rigid insulation. Insulation used 

for below-grade application must be in 

compliance with ASTM C 578 Standard.

(Top) The walls use advanced framing 

with 2x6 studs at 24 inches on center and 

XPS rigid foam sheathing on exterior walls 

instead of OSB. 

(Bottom) Ceiling trusses are designed 

to span the entire home. There are no 

bearing walls for the roof in the interior 

of the home. All ducts are located within 

conditioned space. The duct shown here is 

the fresh air intake for the house.

BUILDING AMERICA BEST PRACTICES SERIES

2
The advanced wood framing (2x6 at 24-inch on center) uses less lumber 

and leaves more room for the R-19 fiberglass batts on the interior walls. 

One-inch (R-5) XPS rigid foam is used for sheathing instead of OSB on 

the exterior walls. The sheathing is taped at the seams and braced at the 

corners and then covered with a water-resistant barrier (house wrap) that 

is fastened and taped. The exterior is finished with vinyl siding. Blower 

door tests show air tightness of less than 3.6 air changes per hour at 50 

Pascals of pressure (~0.15 ACHnat infiltration).

The heating, ventilation, and air-conditioning (HVAC) system includes 

an 8.4 HSPF, 14.5 SEER heat pump. A runtime positive ventilation 

system is dampered with programmable exhaust ventilation. Ducts are 

installed within the conditioned space in open-web floor trusses and are 

tested for leakage to achieve less than 5%. 

The hot water system uses a 0.92 energy factor (EF) electric tank hot water 

heater. All other appliances are ENERGY STAR. Windows are vinylframed, double-glazed low-e with argon fill (U-value=0.32, SHGC=0.31), 

and the lighting is 100% hardwired compact fluorescent lighting.

Innovation

Urbane Homes incorporates improvements to its energy-efficiency 

package on a yearly basis. 

To ensure adherence to quality standards, Urbane Homes holds preconstruction meetings to coordinate trade contractors and ensure buy-in 

from the site superintendent. They provided training sessions for their 

subcontractors on the use of newer products like exterior rigid foam and 

they developed a framing manual for the special techniques they expect 

their framers to use. 

“Our framers do the majority of our air sealing, so when we make 

changes to our process, they get an updated manual and do a great job 

with it,” said Gilbert.

All of Urbane’s houses meet the Building America 40% savings standard 

and are five-star ENERGY STAR certified. ENERGY STAR provides 

third-party testing for energy efficiency.

Health, Durability, Sustainability

Greater Louisville gets 44 inches of rain annually. Moisture and mold 

are a common problem for homes in the area. Urbane Homes builds 

from the ground up to keep moisture from getting into their houses. 

Instead of the oriented strand board (OSB) that many builders use, 

Urbane uses XPS rigid foam sheathing for exterior walls. OSB can 

absorb and trap moisture in a mixed-humid climate. 

The XPS rigid foam sheathing is taped at 

the seams and covered with house wrap 

to provide a drainage, air barrier, and 

thermal barrier.

3

CASE STUDY: URBANE HOMES
Dollars and Sense

The energy-efficiency upgrades cost about $1,465 per house, which 

adds about $129 a year to a mortgage (based on a 30-year term and 7% 

interest). But the homeowner enjoys an estimated $713 a year in energy 

savings, for a net annual gain to the homeowner of $584. 

Urbane Homes is working with the NAHB Research Center to design 

a building envelope with a much higher level of insulation. They are 

also researching alternative HVAC strategies. These should help Urbane 

Homes achieve 50% savings over the Building America benchmark while 

maintaining affordability. 

Table 1. Added Costs and Savings of Energy-Efficient 

Measures for Urbane Homes’ 2,184 Slab Model

Total Energy Savings* 44%

Total Added Builder Costs** $1,612

Annual Mortgage Payment Increase*** $129

Annual Utility Savings $713

Annual Net Cash Flow to the Homeowner $584

*Compared to the Building America benchmark.

**Costs are based on builder estimates and manufacturers’ data. These costs do not include solar 

photovoltaic systems and do not reflect rebates, incentives, and subsidies.

***The annual mortgage payment is an estimate based on a 30-year mortgage with a 7% fixed 

interest rate.

The Bottom Line

Urbane Homes has become a leader in high-performance homes in 

a remarkably short time, receiving industry honors for design and 

construction approaches that raise the level of energy efficiency and 

green building beyond the typical practices of the area. 

Urbane has built five or more homes per year since their original 

community of 10. Urbane Homes’ dollar sales volume has doubled 

every year since they started building, and they’ve already had repeat 

buyers who sold their original Urbane homes at a significant profit. 

The builders admit that most of their customers initially are more 

interested in price and location, but as homeowners learn how much 

money the house will save them on energy costs, they get excited about 

the energy-efficiency features. 

“We’re very passionate about what we do and people can see that,” said 

Gilbert. “We just keep getting busier and busier.”

For More Information

www.buildingamerica.gov 

EERE Information Center 

1-877-EERE-INF (1-877-337-3463) 

eere.energy.gov/informationcenter

PNNL-SA-83102 September, 2011

Key Features 

•	 Advanced 2"x 6" wood framing at

24" on center

•	 Attic insulation: R-50 blown

fiberglass 

•	 Wall insulation: 1" (R-5) XPS foam

sheathing with R-19 fiberglass batts

•	 Foundation insulation: 1" (R-5) XPS

below slab, 2" (R-10) EPS exterior

foundation, 11⁄4" (R-5) EPS interior

foundation

•	 Homes with basements: 2" (R-10)

EPS exterior, R 13 fiberglass batts in

interior walls

•	 Windows: Vinyl-framed, doubleglazed, low-e with argon fill 

(U-0.32, SHGC=0.31)

•	 Blower door test: Less than

3.6 ACH@50PA (~0.15 ACHnat 

infiltration)

•	 8.4 HSPF, 14.5 SEER heat pump

•	 Runtime positive ventilation system

•	 0.92 EF electric tank hot water

heater

•	 Ducts in conditioned space with less

than 5% leakage 

•	 100% hardwired CFLs

•	 ENERGY STAR appliances

•	 HERS scores: 57-62

BUILDING AMERICA BEST PRACTICES SERIES

4
Pine Mountain Builders, a partnership between the owners of Fortress 

Construction and Cousins Properties, has teamed up with the U.S. 

Department of Energy’s Building America program to build homes that 

achieve HERS scores as low as 59. (A typical new American home has a 

score of 100.) 

Since 2005, Pine Mountain Builders has been working with Integrated 

Building and Construction Solutions (IBACOS) and Southface 

Energy Institute, both Building America research partners, to improve 

the energy efficiency of their homes. With the help of IBACOS and 

Southface, Pine Mountain Builders has used innovation to overcome 

technical challenges to meet and exceed the high standards of Callaway 

Gardens’ Longleaf sustainable resort community. Located in western 

Georgia near the non-profit Callaway Gardens Wetlands Preserve, 

this community was designed to serve as an example of sustainable 

development practices that are energy efficient and protect area wilderness. 

With help from Building America, Pine Mountain Builders completed 

its first 11 homes of 140 at Callaway Gardens in 2007. “We love the 

program,” said co-owner Mike Guinan. “We learn and improve every 

day. With IBACOS we can experiment with new systems and products,” 

explains Guinan. 

Although homebuyers may initially be drawn by the development’s 

proximity to nature, they soon find that their homes perform 

extraordinarily well and can reduce their electricity bills to as little as 

$50 a month, or about half of the state average.

BUILDING TECHNOLOGIES PROGRAM

Pine Mountain Builders worked with 

IBACOS, a DOE Building America research 

partner, to come up with designs that use 

off-the-shelf parts to build homes that look 

conventional but are both environmentally 

sustainable and energy efficient.

Building America Best Practices Series

Volume 16. 40% Whole-House Energy Savings in the 

Mixed-Humid Climate

Case Study: 

Pine Mountain Builders

Pine Mountain, Georgia

BUILDER PROFILE

Builder: Pine Mountain Builders

Contact: Mike Guinan, Manager 

(706) 663-8443 

www.callawaygardensliving.com/pinemountain-builders.html

Founded: 2004

Where: Pine Mountain, Georgia

Employees: 5

Development: Callaway Gardens 

(140 lots) and Blalock Lakes

Square Footage: 1,192 to 3,124 ft2

Size: 2-4 bedrooms

Price Range: $300,000 to $450,000

R
Energy-Efficiency Measures

The homes are located in western Georgia’s mixed-humid climate, 

approximately 70 miles southwest of Atlanta, and range from one story, 

3 bedrooms, and 1,929 ft2 at approximately $355,000 to two stories, 

4 bedrooms, and 3,124 ft2, at a cost of up to $450,000. 

Pine Mountain Builders first worked with IBACOS to design homes 

that used 30% less energy than the Building America Benchmark (a 

home built to the 1993 Model Energy Code). These designs became their 

standard homes. Now further work with IBACOS has enabled them 

to reach the 40% savings mark. Using off-the-shelf technologies, Pine 

Mountain offers a suite of energy-saving features designed for highperformance in Georgia’s mixed-humid climate. These features include 

low-emissivity windows, passive design to reduce heat gain, tightly 

sealed thermal envelope, an efficient HVAC equipment and duct system 

design, efficient appliances, and independent testing.

Because the mixed-humid climate requires a great deal of cooling, the 

builders chose low-emissivity, wood-framed, double-glazed windows 

filled with argon and rated U=0.38 and SGHC=0.35. Solar gain is 

also mitigated through the use of architectural shading, such as low 

overhangs, and the preservation of mature trees to provide shade. 

The thermal envelopes of Pine Mountain’s homes are built to be 

airtight. Blower-door tests show 1.0 to 1.8 air changes per hour at 50 

Pascals of air pressure. A cathedralized, sealed attic with R-30 lowdensity spray foam insulation is indirectly conditioned by the HVAC 

system. The walls are 2x4 16-inch on-center and the cavities are filled 

with R-13 low-density spray foam. Above grade, 75% of the exterior 

walls are covered with a 1⁄2-inch R-3 extruded polystyrene (XPS) rigid 

foam insulation. Instead of oriented strand board sheathing, the 

builders recently began using structural XPS foam insulated sheathing 

panels. The structural panels provide extra insulation and resist moisture 

to protect the home from the humid climate. 

The HVAC system is designed to achieve ASHRAE 62.2 whole house 

ventilation requirements by placing the ventilation, heat pump, and 

ducts within the semi-conditioned space of the sealed attic. An air 

cycler provides fresh air to the house at an average of 20 cfm, while a 

14 SEER/HPSF 8.0 heat pump provides cooling and heating. All air 

ducts are sealed with mastic at the joints. Some homes employ a ground 

source heat pump for heating, cooling, and water heating, pushing 

overall home energy savings to the 50% savings level compared to the 

Building America benchmark (a home built to the 1993 Model Energy 

Code). The homes achieve 30% energy savings compared to homes built 

to the Georgia construction code.

The builder installed only ENERGY STAR appliances, and 75% of 

the light fixtures are CFL.

Unvented attics insulated with R-30 

low-density spray foam provide a semiconditioned space for the high-efficiency 

heat pump and ducts. 

Framing is covered with XPS foam 

structural insulated sheathing instead 

of OSB. The foam sheathing provides 

R-3 of insulation and protection against 

moisture. The wall cavities are filled with 

an additional R-13 low-density spray foam 

insulation, which provides air sealing as 

well as insulation.

BUILDING AMERICA BEST PRACTICES SERIES

2
Health, Durability, Sustainability

Pine Mountain Builders has set aggressive environmental performance 

measures that go beyond energy efficiency. The builder uses low-VOC 

paints and installs carbon-monoxide monitors and low-VOC carpets in 

each home. Pest controls are applied externally around the perimeter 

of the home to reduce human exposure. Garages are detached, which 

keeps fumes out of the house. The slab-on-grade foundation is raised to 

protect the home from water damage and sits on 4-ft-deep stemwalls that 

extend below the frostline. 

To improve water efficiency, the builders have included low-flow 

showerheads, dual-flush toilets, high-efficiency washing machines, and 

rainwater harvesting for drip irrigation. 

The builder grinds organic construction debris on site to use for mulch 

blankets that absorb rainfall to minimize runoff. Other erosion control 

measures include silt fences, permeable driveways and walkways, 

planting native species, and preservation of existing trees. The builder is 

registered in the NAHB’s Building With Trees program. Each home is 

framed with sustainably harvested lumber. 

Innovation

The company works with EarthCraft House, a regional program 

developed by the Southface Energy Institute that grades and certifies 

homes based on energy efficiency, indoor air quality, water efficiency, 

and other metrics for sustainability throughout the construction 

process. The builder also works with Callaway Gardens’ Design 

Review Committee to ensure that the construction of its homes causes 

minimal impact to area habitat and water resources. Beyond providing 

third-party testing for energy efficiency, homes earning an EarthCraft 

House certification are also built to ENERGY STAR levels of efficiency. 

Certification requires builders to provide documentation of design goals 

and third-party verification before, during, and after the construction 

process to ensure overall building performance is as designed. This 

arduous process ensures that the finished building performs as it was 

designed. Furthermore, the builders take each home’s alignment with 

the sun into consideration, both to adjust the amount and location of 

windows and doors and to properly determine the home’s heating and 

cooling loads. 

Pine Mountain Builders has worked with IBACOS and Southface 

over the past few years to reach both the 30% and 40% targets. Pine 

Mountain Builders have also begun working toward the 50% energy 

savings level in future designs. With more than 10 years of experience in 

building homes, Pine Mountain Builders has longstanding relationships 

with its trade partners that ensure its performance standards are met 

with the use of conventional building materials. 

Key Features

•	 HERS scores: 59 to 85

•	 Foundation: Slab on grade, perimeter

slab-edge insulation

•	 Siding: Wood shake cladding with

R-3 XPS structural insulated foam 

sheathing

•	 Walls : 2x4 16-inch on center, R-13

low-density spray foam insulation

•	 Attic: Cathedralized, sealed, R-30

low-density spray foam insulation

•	 HVAC: ACCA Manual J-sized 14

SEER/HPSF 8.0 heat pump

•	 Ventilation: Air-cycler fresh-air

supply with 20 cfm per hour 

•	 Duct system: ACCA Manual D sized,

located in semi-conditioned attic 

space, mastic sealed at joints

•	 Water heating: 40 gallon electric,

0.93 EF

•	 Windows: Low-E, double-pane,

wood-framed windows, U=0.36, 

SHGC=0.30

•	 Lighting: 75% CFL

•	 Appliances: All ENERGY STAR

3

CASE STUDY: PINE MOUNTAIN BUILDERS
“We like to build the most energy-efficient and best-performing home 

with off-the-shelf parts,” explains manager Mike Guinan of Pine 

Mountain Builders. “We don’t have any solar or PV arrays. It looks like 

an ordinary house but it performs way better.” 

Dollars and Sense

The builders have calculated that their efficiency measures add $917 per 

year (based on a 30-year mortgage at 7% interest), compared to a home 

built to Georgia code. IBACOS calculated the energy improvements can 

save homeowners up to $1,180 per year on their utility bills for a net 

gain to the homeowners of $263 per year. 

Table 1. Calculated Costs and Savings of Energy-Efficiency 

Features for Pine Mountain Builders, Pine Mountain, Georgia

Total Energy Savings1 41%

Total Added Builder Costs2 $2,564

Annual Utility Savings $1,180 

Annual Mortgage Payment Increases2,3 $917 

Annual Net Cash Flow to the Homeowner $263 

1 Savings are in comparison to the Building America benchmark (a home built to the 1993 

Model Energy Code) 

2	 Builder costs were estimated by builders and Building America team. Costs include a 10%

markup. Incentives and rebates are not included.

3	 Mortgage costs are based on a 30-yr fixed mortgage at 7% interest; inflation is not

considered.

The Bottom Line 

With the downturn in the housing market, Pine Mountain Builders’ 

construction rate has dropped from 50-75 homes per year to 15 homes 

in 2010. Guinan sees a need for builders to help homebuyers understand 

the role efficient and sustainable design plays in the overall quality of 

their home. “The demand side, that’s where I think we need to put a lot 

of our attention,” he said.

Homebuyers may begin the process focusing on amenities such as garage 

size and swimming pools, according to Guinan but energy-efficient 

features really begin to shine after the home is built. “After they move in, 

they’re saying, ‘Wow, this is great! I can’t believe how well all this stuff 

works!” explains Guinan. 

“We try to do the extreme best with what is available to us today,” 

explains Guinan. “We think that our greatest success is our overall 

customer satisfaction. Our consumers are enjoying greater overall 

indoor air comfort and lower utility costs.” 

For More Information

www.buildingamerica.gov 

EERE Information Center 

1-877-EERE-INF (1-877-337-3463) 

eere.energy.gov/informationcenter

PNNL-SA-83101 September 2011

With help from IBACOS, Pine Mountain

Builders has improved its energy efficiency 

from 30% to 40% savings over the Building

America benchmark and HERS scores of

59. They are now working toward 50%

energy savings in future designs.

BUILDING AMERICA BEST PRACTICES SERIES

4
Appendix I.

Homebuyer’s Checklist

Homebuyers, take this with you when you go house shopping 

to make sure you get an energy-efficient home.

MEASURE Building America

Recommendations

Builder

#1

Builder

#2

Builder

#3

HEATING AND COOLING EQUIPMENT

ENERGY STAR qualified air conditioning of SEER* 13 or greater Yes

ENERGY STAR qualified heat pump Yes

ENERGY STAR qualified boiler Yes

ENERGY STAR qualified sealed combustion gas furnace 

of 90 AFUE* or higher

Yes

ENERGY STAR qualified programmable thermostat Yes

Ductwork sealed with mastic (no duct tape) Yes

5% or less duct leakage found with pressure test 

10% allowed if all ducts are located in the conditioned space. Yes

Duct Insulation: R-4 in conditioned space, R-8 in attic, R-6 in crawlspace Yes

House plans show duct layouts Yes

Ducts located in conditioned space Yes

Ducts sized according to industry standards in Manual D Yes

Heating and cooling equipment sized according to industry standards 

in Manual J Yes

House pressure balanced with jump ducts or transfer grills Yes

HVAC* equipment and duct work inspected and tested after installation Yes

Filter with MERV rating of 8 or higher installed on the central air handler Yes

Air handler isolated from garage by a thermal barrier (insulation) 

and air barrier (e.g., drywall sealed at seams) Yes

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MEASURE Building America

Recommendations

Builder

#1

Builder

#2

Builder

#3

INSULATION (take a look at a house under construction before sheetrock is installed)

Insulation installed behind tubs, showers, stairs, fireplaces, etc. Yes

Insulation fills entire cavities—no voids or compressed batts—

Attic insulation level without gaps and covers entire attic floor Yes

Rim joists are insulated Yes

Rigid foam insulation applied under exterior siding or stucco Yes

WINDOWS (take a look at a house under construction before exterior siding is installed)

ENERGY STAR qualified windows, doors, and skylights Yes

Windows flashed to help repel water Yes

MOISTURE MANAGEMENT (take a look at a house under construction before exterior siding is installed)

Ground slopes away from house on all sides or drainage is addressed Yes

Housewrap, building paper, or rigid foam exterior insulation, taped at 

seams and caulked at edges, covers OSB walls in wood-framed houses Yes

Roof flashing in valleys, where walls and roofs intersect, and at other 

places where water may enter the house—the more complex the roof, 

the more flashing you should see. Diverter flashing is used where roofs 

touch walls to direct water away from wall and into gutter.

Yes

Air gap between stucco, brick, or masonry cladding and housewrap Yes

Overhangs for shade and to direct water away from walls Yes

No polyethelyene in interior side of wall assembly. 

No vinyl wallpaper on interior face of exterior walls. Yes

Trees planted ten feet from house, no overhanging branches Yes

Plantings 18 to 36 inches away from the foundation Yes

No wood or siding in direct contact with ground minimum 8 in. clearance Yes

AIR BARRIERS

Follow ENERGY STAR Version 3.0 thermal boundary guidelines Yes

All penetrations through exterior walls sealed Yes

Careful sealing of sheetrock or exterior sheathing Yes

Recessed can lights rated for insulation contact and airtight (ICAT) Yes

Electrical boxes on exterior walls caulked or gasketed Yes

Holes into attic sealed Yes

Attic hatch weather-stripped and insulated Yes

Air leakage tested with blower door test Yes

Draft stops installed behind tubs, showers, stairs, and fireplaces, 

under kneewalls and cantilevered floors, and in floor joist bays 

spanning garages and living spaces

Yes

Garage completely sealed from conditioned areas of house Yes

Sill plates gasketed or sealed Yes

APPENDIX I / BUILDING AMERICA BEST PRACTICES SERIES

A1.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
MEASURE Building America

Recommendations

Builder

#1

Builder

#2

Builder

#3

FOUNDATION MEASURES

Radon control measures installed Yes

4- to 6-inch gravel base under slab and basement floors Yes

Polyethylene (plastic) vapor barrier between gravel and slab Yes

Slab or open web foundation preferred. If crawlspace, 

then unvented and insulated on interior walls. Yes

Termite flashing added at sill plate Yes

PLUMBING

No pipes in exterior walls Yes

Pipe insulation Yes

VENTILATION

Whole-house mechanical ventilation installed Yes

Spot ventilation installed in kitchen and bathrooms Yes

Clothes dryers vented to the outside Yes

Gas-fired furnaces or water heaters sealed combustion, 

direct vented, or power vented Yes

Carbon monoxide detector installed in homes with a 

combustion appliance or attached garage Yes

Attached garages are ventilated Yes

FRAMING

Use Optimum Value Engineering (also called Advanced Framing) 

as permitted by local code:

- 2x6 24 in. oc instead of 2x4 18 in. oc studs

- Align framing members from floor joists to wall studs to rafters

- Use single top plates and single headers where possible

- Use two-stud corners and drywall clips instead of 3-stud corners

- Hurricane strapping and rods

- Borate-treated lumber

Yes

OTHER

Low VOC interior coatings Yes

Low VOC adhesives Yes

Low VOC cabinets Yes

CFL lighting Yes

OTHER FEATURES FOR COMPARISON

*SEER: Seasonal Energy Efficiency Ratio | *AFUE: Annual Fuel Utilization Efficiency | *HVAC: heating, ventilation, and air conditioning

A1.3

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APPENDIX I / BUILDING AMERICA BEST PRACTICES SERIES

A1.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Appendix II.

DOE Building Energy Code 

Resource Center Code Notes

A meeting with the building department before construction is well 

advised. Should your code official need information in support of 

the new techniques you may use in an energy-efficient home, this 

appendix contains websites and a sample document that may be 

helpful. A set of draft code notes are available on DOE’s Building 

Energy Codes Resource Center website. These draft documents 

are written for code officials and provide a description of energyefficiency techniques, citations to relevant codes, and guidance for 

plan reviews and field inspections. 

Here is a list of available code notes that can help re-assure your 

local code official that the proposed techniques are both safe and 

in compliance with the model codes. The code notes are available at 

www.energycodes.gov/support/code_notes.stm.

•	 Single Top Plate

•	 No Headers in Nonbearing Walls

•	 Header Hangers in Bearing Walls

•	 Open Spaces as Return-Air Options

•	 Details for Mechanically Vented Crawl Spaces

•	 Ventilation Requirements for Condensing Clothes Dryers

•	 Drywall Clips

•	 Rigid Board Insulation Installed as Draft Stop in Attic Kneewall

•	 Whole-House Mechanical Ventilation

•	 Residential Heating and Cooling Load Calculation Requirements

•	 Conditioned Attics.

We have included one of these Code Notes as a sample in this 

document, the Code Note for Rigid Board Insulation Installed as 

Draft Stop in Attic Kneewall. You will find it on the pages that follow.

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Rigid Board Insulation Installed as Draft Stop in Attic Kneewall -

Code Notes (DRAFT)

Framing kneewall

Rigid board insulation (foam plastic) is an effective draft stop and also increases the R-value of the attic

kneewall if installed on the attic side of the kneewall, replacing the need for separate draft stop and insulation

products. The IRC requires foam plastic insulation to be protected against ignition by using fiberglass batt

insulation, gypsum board or other products that meet the flame and smoke density requirements. Foam

plastic products rated for flame and smoke density can be installed without such a protective covering.

Insulating attic kneewalls between a conditioned space with vaulted ceilings and the attic is important to

reduce energy loss through the wall, especially in the summer months. To be effective, the insulation installed

in the kneewalls must be supported so that it stays in contact with the gypsum board, and protected against

air moving through the insulation.

http://energycode.pnl.gov/cocoon/energy/ Page 1 of 3

APPENDIX II / BUILDING AMERICA BEST PRACTICES SERIES

A2.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Kneewall sheathing insulation to increase R-value to equal the outside wall.

Foam plastic insulation can be installed on the attic side of the attic kneewall (see Figure) to both act as a

draft stop between the conditioned house and the unconditioned attic and to increase the insulation R-value of

the attic kneewall. Installing such an insulating backing in the kneewall supports the fiberglass batt insulation

between framing members, replaces an air barrier, and adds insulating value to the attic kneewall.

Plan Review

1. Verify that plastic insulation called out on the construction detail meets the ASTM E 84 requirements for

flame spread and smoke development. Require manufacturer literature or an ICC Evaluation Service

report.

2. Verify that the insulation R-value of the foam plastic insulation called out on the building plans meets or

exceeds the R-value requirements called for on the energy code compliance documentation (only if credit

has been taken for the foam plastic insulation).

Field Inspection

1. Verify that the foam plastic insulation installed in the field is consistent with that called out on the building

plans.

2. Verify that the insulation R-value specified on the insulation meets or exceeds the R value called out on the

plans or documentation.

3. Verify that that sealant has been installed around the edges of the insulation and that any holes or

penetrations in the foam plastic insulation are sealed.

Code Citations

http://energycode.pnl.gov/cocoon/energy/ Page 2 of 3

The R-value of the kneewall sheathing insulation should equal the R-value of the exterior wall insulation.

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APPENDIX II / BUILDING AMERICA BEST PRACTICES SERIES

A2.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Appendix III.

Energy & Housing Glossary

Accreditation

The process of certifying a Home Energy 

Rating System (HERS) as being compliant 

with the national industry standard operating 

procedures for Home Energy Rating System.

AFUE Annual Fuel Utilization 

Efficiency (AFUE)

Measures the amount of fuel converted to 

space heat in proportion to the amount of 

fuel entering the furnace. This is commonly 

expressed as a percentage. A furnace with an 

AFUE of 90 could be said to be 90% efficient. 

AFUE includes any input energy required 

by the pilot light but does not include any 

electrical energy for fans or pumps. 

Air Barrier

Any material that restricts air flow. In wall 

assemblies, the exterior air barrier is often a 

combination of sheathing and either building 

paper, housewrap or board insulation. The 

interior air barrier is typically gypsum board. 

Air Flow Retarder

Air flow retarders are used to form a home’s 

pressure boundary. They retard air flow 

through the home’s walls, floors, and ceiling. 

Common air flow retarder materials include 

drywall that is taped and mudded at seams; 

OSB or plywood subflooring that is caulked at 

seams; plastic sheets placed between drywall 

and framing (should not to be used in hot and 

humid climates); exterior rigid foam insulating 

sheathing that is taped at seams; and building 

paper that is taped at seams. 

Building Envelope

The outer shell, or the elements of a building, 

such as walls, floors, and ceilings, that enclose 

conditioned space. See also Pressure Boundary 

and Thermal Boundary.

Btu (British Thermal Unit)

A standard unit for measuring energy. One Btu 

is the amount of energy required to raise the 

temperature of one pound of water by one 

degree Fahrenheit from 59 to 60. An InchesPounds unit.

CABO (Council of American 

Building Officials)

The previous umbrella organization for the 

three nationally recognized model code 

organizations in the United States: the Building 

Officials & Code Administrators International, 

Inc. (BOCA), the International Conference of 

Building Officials (ICBO), and the Southern 

Building Code Congress International (SBCCI). 

All were incorporated into the International 

Code Council in ICC in November of 1997 

with the goal of developing a single national 

building code in the United States. 

Capacity

The rate at which a piece of equipment works. 

Cooling capacity is the amount of heat a 

cooling system can remove from the air. For air 

conditioners total capacity is the sum of latent 

capacity, the ability to remove moisture from 

the air, and the sensible capacity, the ability to 

reduce dry-bulb temperature. Heating system 

capacity indicates how much heat a system 

can provide. Heating and cooling capacities are 

rated in Btu per hour.

Chase

An enclosure designed to hold ducts, 

plumbing, electric, telephone, cable, or other 

linear components. A chase designed for ducts 

should be in conditioned space and include air 

flow retarders and thermal barriers between it 

and unconditioned spaces such as attics.

Construction Documents

The drawings (plans) and written specifications 

that describe construction requirements for 

a building.

COP (Coefficient of 

Performance)

A measure of efficiency typically applied 

to heat pumps. The COP for heat pumps 

is the ratio, at a given point in time, of net 

heat output to total energy input expressed 

in consistent units and under designated 

conditions. Heat pumps result in a COP 

greater than 1 because the system delivers or 

removes more heat energy than it consumes. 

Other specific definitions of COP exist for 

refrigeration equipment. See HSPF for a 

description of a unit for seasonal efficiency.

Debt-to-Income Ratio

The ratio, expressed as a percentage, which 

results when a borrower’s total monthly 

payment obligations on long-term debt are 

divided by their gross monthly income. This is 

one of two ratios (housing expense-to-income 

ratio being the other) used by the mortgage 

industry to determine if a prospective borrower 

qualifies (meets the underwriting guidelines) for 

a specific home mortgage. Fannie Mae, Freddie 

Mac and FHA underwriting guidelines set an 

upper limit of 36% on this value for conventional 

loans but increase (“stretch”) the ratio by 2% for 

qualifying energy-efficient houses.

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Dry-Bulb Temperature

The temperature of air indicated on an ordinary 

thermometer, it does not account for the 

affects of humidity.

ECM 

(Energy Conservation Measure)

An individual building component or product 

that directly impacts energy use in a building.

EEM 

(Energy-Efficient Mortgage)

Specifically, a home mortgage for which the 

borrower’s qualifying debt-to-income and 

housing expense-to income ratios have been 

increased (“stretched”) by 2% because the 

home meets or exceeds CABO’s 1992 version of 

the Model Energy Code (MEC). This so-called 

“stretch” mortgage is nationally underwritten 

by Fannie Mae, Freddie Mac and the Federal 

Housing Administration (FHA). This term 

is often used generically to refer to any 

home mortgage for which the underwriting 

guidelines have been relaxed specifically for 

energy efficiency features, or for which any 

form of financing incentive is given for 

energy efficiency.

EER (Energy Efficiency Ratio)

A measurement of the instantaneous energy 

efficiency of cooling equipment, normally used 

only for electric air conditioning. EER is the 

ratio of net cooling capacity in Btu per hour to 

the total rate of electric input in watts, under 

designated conditions. The resulting EER value 

has units of Btu per watt-hour.

EF (Energy Factor)

A standardized measurement of the annual 

energy efficiency of water heating systems. 

It is the annual hot water energy delivered 

to a standard hot water load divided by the 

total annual purchased hot water energy 

input in consistent units. The resultant EF 

value is a percentage. EF is determined by a 

standardized U.S. Department of Energy (DOE) 

procedure.

Energy (Use)

The quantity of onsite electricity, gas or 

other fuel required by the building equipment 

to satisfy the building heating, cooling, hot 

water, or other loads or any other service 

requirements (lighting, refrigeration, 

cooking, etc.)

Energy Audit

A site inventory and descriptive record 

of features impacting the energy use in a 

building. This includes, but is not limited to all 

building component descriptions (locations, 

areas, orientations, construction attributes 

and energy transfer characteristics); all energy 

using equipment and appliance descriptions 

(use, make, model, capacity, efficiency and fuel 

type) and all energy features.

ENERGY STAR® Home

A home, certified by the U.S. Environmental 

Protection Agency (EPA), that is at least 30% 

more energy efficient than the minimum 

national standard for home energy efficiency 

as specified by the 1992 MEC, or as defined for 

specific states or regions. ENERGY STAR is a 

registered trademark of the EPA.

Envelope

See Building Envelope

Fannie Mae (FNMA - Federal 

National Mortgage Association)

A private, tax-paying corporation chartered by 

the U.S. Congress to provide financial products 

and services that increase the availability of 

housing for low-, moderate-, and middleincome Americans.

FHA (Federal Housing 

Administration)

A division of the U.S. Department of Housing 

and Urban Development (HUD). FHA’s main 

activity is the insurance of residential mortgage 

loans made by private lenders.

Freddie Mac 

(FHLMC - Federal Home Loan 

Mortgage Corporation)

A stockholder-owned organization, chartered 

by the U.S. Congress to increase the supply 

of mortgage funds. Freddie Mac purchases 

conventional mortgages from insured 

depository institutions and HUD-approved 

mortgage bankers.

Grade Beam

A foundation wall that is poured at or just 

below the grade of the earth, most often 

associated with the deepened perimeter 

concrete section in slab-on-grade foundations.

HERS 

(Home Energy Rating System)

A standardized system for rating the energyefficiency of residential buildings.

HERS Energy-Efficient 

Reference Home (EERH)

The EERH is a geometric “twin” to a home 

being evaluated for a HERS rating and 

according to a newly revised system, is 

configured to be minimally compliant with the 

2004 International Energy Conservation Code.

HERS Provider

An individual or organization responsible for 

the operation and management of a Home 

Energy Rating System (HERS).

HERS Rater

An individual certified to perform residential 

building energy efficiency ratings in the class 

for which the rater is certified.

HERS Index

The HERS Index is a scoring system established 

by the Residential Energy Services Network 

(RESNET) in which a home built to the 

specifications of the HERS Reference Home 

(based on the 2006 International Energy 

Conservation Code) scores a HERS Index of 

100, while a net zero energy home scores a 

HERS Index of 0. The lower a home’s HERS 

Index, the more energy efficient it is in 

comparison to the HERS Reference Home.

Each 1-point decrease in the HERS Index 

corresponds to a 1% reduction in energy 

consumption compared to the HERS Reference 

Home. Thus a home with a HERS Index of 85 

is 15% more energy efficient than the HERS 

Reference Home and a home with a HERS 

Index of 70 is 30% more energy efficient.

Housing Expense-to-Income Ratio

The ratio, expressed as a percentage, which 

results when a borrower’s total monthly 

housing expenses (P.I.T.I.) are divided by their 

gross monthly income. This is one of two 

ratios (debt-to-income ratio being the other) 

used by the mortgage industry to determine 

if a prospective borrower qualifies (meets the 

underwriting guidelines) for a specific home 

mortgage. Fannie Mae, Freddie Mac and FHA 

underwriting guidelines set an upper limit 

of 28% on this value for conventional loans 

but increase (“stretch”) the ratio by 2% for 

qualifying Energy-Efficient Mortgages (EEM).

APPENDIX III / BUILDING AMERICA BEST PRACTICES SERIES

A3.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
Housewrap

Any of several spun-fiber polyolefin rolled 

sheet goods for wrapping the exterior of the 

building envelope.

HSPF (Heating Season 

Performance Factor)

A measurement of the seasonal efficiency 

of an electric heat pump using a standard 

heating load and outdoor climate profile over 

a standard heating season. It represents the 

total seasonal heating output in Btu divided by 

the total seasonal electric power input in watthours (Wh). Thus, the resultant value for HSPF 

has units of Btu/Wh.

Infrared Imaging

Heat sensing camera which helps reveal 

thermal bypass conditions by exposing hot 

and cold surface temperatures revealing 

unintended thermal flow, air flow, and moisture 

flow. Darker colors indicate cool temperatures, 

while lighter colors indicate warmer 

temperatures.

Insulated Concrete Forms (ICFs)

Factory-built wall system blocks that are made 

from extruded polystyrene insulation. Steel 

reinforcing rods are added and concrete is 

poured into the voids, creating a very air-tight, 

well insulated and sturdy wall as the insulation 

is inherently aligned with the exterior and 

interior air barriers.

Insulation Contact, Air-Tight 

(ICAT) Lighting Fixture

Rating for recessed lights that can have direct 

contact with insulation and constructed with 

air-tight assemblies to reduce thermal losses.

Jump Duct

A flexible, short, U-shaped duct (typically 

10-inch diameter) that connects a room to 

a common space as a pressure balancing 

mechanism. Jump ducts serve the same 

function as transfer grilles.

Load

The quantity of heat that must be added to 

or removed from the building (or the hot 

water tank) to satisfy specific levels of service, 

such as maintaining space temperature or hot 

water temperature at a specified thermostat 

setting (see also the definitions of energy 

and thermostat).

Low-E

Refers to a coating for high-performance 

windows, the “E” stands for emissivity or 

re-radiated heat flow. The thin metallic oxide 

coating increases the U-value of the window 

by reducing heat flow from a warm(er) air 

space to a cold(er) glazing surface. Low-E 

coatings allow short-wavelength solar radiation 

through windows, but reflect back longer 

wavelengths of heat.

MEC (Model Energy Code)

A “model” national standard for residential 

energy efficiency. The MEC was developed 

through a national consensus process by 

the Council of American Building Officials 

(CABO) and is the accepted national minimum 

efficiency standard for residential construction. 

Since MEC is a model code, it does not have 

the “force of law” until it is adopted by a local 

code authority. The MEC is used as the national 

standard for determining Energy-Efficient 

Mortgage (EEM) qualification, and it serves 

as the national “reference point” used by 

Home Energy Rating Systems (HERS) in the 

determination of energy ratings for homes.

Mechanical Ventilation

The active process of supplying or removing 

air to or from an indoor space by powered 

equipment such as motor-driven fans and 

blowers, but not by devices such as winddriven turbine ventilators and mechanically 

operated windows.

Optimal Value Engineering 

(OVE)

A strategy for reducing thermal bridging by 

minimizing wall framing needed for structural 

support. Common techniques include 2x6 

framing with 24" on-center spacing, single top 

plates where trusses align with wall framing 

below, properly sized headers, two-stud 

corners, lattice strips at exterior/interior wall 

intersections, and the elimination of excessive 

fire blocking and window framing. This results 

in much more open framing for insulation to 

improve energy efficiency and comfort.

Performance Test

An on-site measurement of the energy 

performance of a building energy feature or an 

energy using device conducted in accordance 

with pre-defined testing and measurement 

protocols and analysis and computation 

methods. Such protocols and methods may 

be defined by national consensus standards 

like those of the American Society of Heating, 

Refrigerating and Air Conditioning Engineers 

(ASHRAE) and the American Society for Test 

and Measurement (ASTM).

P.I.T.I.

An abbreviation which stands for principal, 

interest, taxes, and insurance. These generally 

represent a borrower’s total monthly payment 

obligations on a home loan. The taxes and 

insurance portion are often paid monthly to 

an impound or escrow account and may be 

adjusted annually to reflect changes in the 

cost of each.

Pressure Boundary

The point in a building at which inside air and 

outside air are separated. If a building were 

a balloon, the rubber skin would form the 

pressure boundary. Where inside and outside 

air freely mingle there is no pressure boundary.

Pressurization Test

A procedure in which a fan is used to place a 

house, duct system, or other container, under 

positive or negative air pressure in order to 

calculate air leakage.

RESNET (Residential Energy 

Services Network)

The national association of energy rating 

providers.

Rated Home

A specific residence that is evaluated by an 

energy rating.

R-Value

Measures a material’s ability to slow down or 

resist the transfer of heat energy, also called 

thermal resistance. The greater the R-value, the 

better the resistance, the better the insulation. 

The effective R-value of an insulation material 

will be reduced by gaps, voids, compression or 

misalignment. R-values are the reciprocal of 

U-values. See U-values for more information.

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Sealed Combustion

Sealed combustion means that a combustion 

appliance, such as a furnace, water heater, 

or fireplace, acquires all air for combustion 

though a dedicated sealed passage from 

the outside; combustion occurs in a sealed 

combustion chamber, and all combustion 

products are vented to the outside through a 

separate dedicated sealed vent.

SEER (Seasonal Energy 

Efficiency Ratio)

A measurement similar to HSPF except that 

it measures the seasonal cooling efficiency of 

an electric air conditioner or heat pump using 

a standard cooling load and outdoor climate 

profile over a standard cooling season. It 

represents the total seasonal cooling output in 

Btu divided by the total seasonal electric input 

in watt hours (Wh). The SEER value are units 

of Btu/Wh.

Semi-Permeable

The term vapor semi-permeable describes 

a material with a water vapor permeance 

between 1 and 10 Perms. Water vapor can pass 

through a semi-permeable material but at a 

slow rate.

Shading Coefficient (SC)

The ratio of the total solar heat admittance 

through a given glazing product relative to 

the solar heat admittance of double-strength, 

clear glass at normal solar incidence (i.e., 

perpendicular to the glazing surface).

Site Energy

The energy consumed at a building location or 

other end–use site.

Solar Heat Gain Coefficient 

(SHGC)

SHGC measures how well a window blocks heat 

caused by sunlight. The lower the SHGC rating 

the less solar heat the window transmits. This 

rating is expressed as a fraction between 0 and 

1. The number is the ratio of a window’s solar 

heat admittance compared to the total solar 

heat available on the exterior window surface 

at normal solar incidence (i.e., perpendicular to 

the glazing surface).

Sone

A sound rating. Fans rated 1.5 sones and below 

are considered very quiet.

Source Energy

All the energy used to deliver energy to a site, 

including power generation and transmission 

and distribution losses (also called primary 

energy). Approximately three watts (or 10.239 

British thermal units) of energy is consumed to 

deliver one watt of usable electricity. Building 

America energy saving targets are measured in 

terms of source energy rather than site energy.

Structural Insulated Panels 

(SIPs)

Factory-built insulated wall assemblies that 

ensure full alignment of insulation with 

integrated air barriers. Composed of insulated 

foam board glued to both an internal and 

external layer of sheathing (typically OSB or 

plywood). Many SIP panels are manufactured 

with precut window and door openings.

Supply ducts

The ducts in a forced air heating or cooling 

system that supply heated or cooled air 

from the furnace or air conditioner to 

conditioned spaces.

Thermal Boundary

The border between conditioned and 

unconditioned space where insulation should 

be placed.

Thermal Bridging

Accelerated thermal flow that occurs 

when materials that are poor insulators 

displace insulation.

Thermostat

A control device that measures the 

temperature of the air in a home or the water 

in a hot water tank and activates heating or 

cooling equipment to cause the air or water 

temperature to remain at a pre-specified value, 

normally called the set point temperature.

Ton(s) of Refrigeration

Units used to characterize the cooling capacity 

of air conditioning equipment. One ton equals 

12,000 Btu/h.

U-Value

Measures the rate at which heat flows or 

conducts through a building assembly (wall, 

floor, ceiling, etc.). The smaller the U-value the 

more energy efficient an assembly and the 

slower the heat transfer. Window performance 

labels include U-values (calling them U factors) 

to help in comparing across window products.

Ventilation

The controlled movement of air into and out 

of a house.

W (watt)

One of two (Btu/h is the other) standard units 

of measure for the rate at which energy is 

consumed by equipment or the rate at which 

energy moves from one location to another. 

It is also the standard unit of measure for 

electrical power.

Wet-Bulb Temperature

A measure of combined heat and humidity. 

At the same temperature, air with less relative 

humidity has a lower wet-bulb temperature. 

See Dry-Bulb Temperature.

Wind Baffle

An object that serves as an air barrier for 

the purpose of blocking wind washing at 

attic eaves.

Wind-Washing

Air movement due to increased pressure 

differences that occur at the outside corners 

and roof eaves of buildings. Wind-washing 

can have significant impact on thermal and 

moisture movement and hence thermal 

and moisture performance of exterior wall 

assemblies.

Xeriscaping

Landscaping that minimizes outdoor water use 

while maintaining soil integrity and building 

aesthetics. Typically includes emphasis on 

native plantings, mulching, and no or limited 

drip/subsurface irrigation.

Zero Energy House

Any house that over time, averages out to netzero energy consumption. A zero energy home 

may supply more energy than it needs during 

peak demand, typically using one or more solar 

energy strategies, energy storage and/or 

net metering.

APPENDIX III / BUILDING AMERICA BEST PRACTICES SERIES

A3.4 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
AC air conditioner

ACCA Air Conditioning Contractors of America

ACH air changes per hour

ACI Affordable Comfort Incorporated

AFUE Annual Fuel Utilization Efficiency

AHRI Air-Conditioning, Heating, and 

Refrigeration Institute

AHU air-handler unit

AIA American Institute of Architects

AL air leakage

ALA American Lung Association

ANSI American National Standards Institute

ARRA American Recovery and Reinvestment Act

ASCE American Society of Civil Engineers

ASHRAE American Society of Heating, Refrigerating, 

and Air Conditioning Engineers

ASTM American Society for Testing and Materials

BECT Building Energy Code Training

BEES Building Energy Efficiency Standard

BEopt Software developed by NREL for identifying 

optimal building design

BESTEST A benchmark for building energy simulation: 

Building Energy Simulation Test and 

Diagnostic Method

BFE base flood elevation

BII Building Industry Institute

BIRA Building Industry Research Alliance

BPI Building Performance Institute

BSC Building Science Corporation

BSC Building Science Consortium

BTU British thermal unit

CAD computer-aided design

CARB Consortium for Advanced Residential Buildings

CDD cooling degree days

CEE Consortium for Energy Efficiency

CERL Construction Engineering Research Laboratory

CFL compact fluorescent light

CFM cubic feet per minute

CFR U.S. Code of Federal Regulations

CGSB Canadian General Standards Board

CO carbon monoxide

COP coefficient of performance

CR condensation resistance

CRI color-rendering index

CT color temperature

DHW domestic hot water

DOE U.S. Department of Energy

Appendix IV.

Acronyms and Abbreviations

A4.1

BUILDING AMERICA BEST PRACTICES SERIES / APPENDIX IV

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 A4.1
DOE2 Building energy analysis program that can predict 

the energy use and cost for all types of buildings

ECM electronically commutated motor (or energy 

conservation measure)

EEBA Energy and Environmental Building Alliance

EEM Energy-efficient mortgages

EER energy efficiency rating

EERH Energy-Efficient Reference Home

EF energy factor

EFL Environments for Living®

EGUSA Energy-Gauge USA software (FSEC’s residential 

front-end user interface for DOE2.1E simulation tool)

EPDM Ethylene Propylene Diene Monomer

EPA U.S. Environmental Protection Agency

EPS expanded polystyrene

ERV energy recovery ventilator

EVHA Energy Value Housing Award

FEMA Federal Emergency Management Agency

FF framing factor

FFA finished floor area

FHA Federal Housing Administration

FHD first hour delivery

FIRM Flood Insurance Rate Map

FSEC Florida Solar Energy Center

GAMA Gas Appliance Manufacturers Association

GenOpt generic optimization program

HDD heating degree days

HERS Home Energy Rating System developed by RESNET

HPL high-performance lighting

HRV heat recovery ventilator

HSPF Heating Seasonal Performance Factor

HUD U.S. Department of Housing and Urban Development

HVAC heating, ventilating, and air conditioning

HVI Home Ventilating Institute

IAQ indoor air quality

IBACOS Integrated Building and Construction Solutions

IC insulated ceiling

ICAT insulation-contact air-tight

ICC International Code Council

ICF insulated concrete form

IDEC indirect-direct evaporative cooler

IDP integrated design process

IECC International Energy Conservation Code

IEQ indoor environmental quality

IHP Industrialized Housing Partnership

IOSEU incremental overall source energy use

IRC International Residential Code

LED light emitting diode

LEED Leadership in Energy and Environmental Design

mcf million cubic feet

MEC Model Energy Code (replaced by IECC in 1998)

MEF modified energy factor

MERV Minimum Efficiency Reporting Value

NAECA National Appliance Energy Conservation Act

NAHB National Association of Home Builders

NAHBRC National Association of Home Builders Research 

Center

NASEO National Association of State Energy Officials

NATE North American Technician Excellence

NFRC National Fenestration Rating Council

NHQ National Housing Quality

NREL National Renewable Energy Laboratory

NZEH net-zero energy home

o.c. on center

ORNL Oak Ridge National Laboratory

OSB oriented strand board

Pa Pascal, unit of pressure measurement

APPENDIX IV / BUILDING AMERICA BEST PRACTICES SERIES

A4.2 Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011
PATH Partnership for Advancing Technology in Housing

PEX cross-linked polyethylene tubing

NFIP National Flood Insurance Program

NIBS National Institute of Building Sciences

NRDC Natural Resources Defense Council

PITI principal, interest, tax, and insurance

PNNL Pacific Northwest National Laboratory

PSC permanent split-capacitor motors

PV photovoltaics

R-Value A measure of thermal resistance used to describe 

thermal insulation materials in buildings

R.A.P. return-air pathway

RESNET Residential Energy Service Network

RH relative humidity

SA supply air

SBIC Sustainable Buildings Industry Council

SC shading coefficient

SEER seasonal energy efficiency ratio

SFHA special flood hazard areas

SHGC solar heat gain coefficient

SHW solar hot water

SLA specific leakage area

SIP structural insulated panels

TIP Termite Infestation Probability

TMY2 typical meteorological year weather data

TOU time of use

TXV thermostatic expansion valve

UA heat loss coefficient

UL Underwriter’s Laboratory

USDA U.S. Department of Agriculture

USGBC U.S. Green Building Council

USGS U.S. Geological Survey

U-Value The thermal transmittance of a material, 

incorporating the thermal conductance of the 

structure along with heat transfer resulting 

from convection and radiation.

UV ultraviolet

VOC volatile organic compounds

VT visible transmittance

WUFI modeling program for simulating heat 

and moisture transfer

XPS extruded polystyrene

ZEH zero energy home

ZNE zero net energy

A4.3

BUILDING AMERICA BEST PRACTICES SERIES / APPENDIX IV

Volume 16. 40% Whole-House Energy Savings in the Mixed-Humid Climate – September 2011 A4.3


EERE Information Center 

1-877-EERE-INF (1-877-337-3463) 

www.eere.energy.gov/informationcenter

September 2011 – PNNL-20890 

For information on Building America 

visit www.buildingamerica.gov. 

The website contains expanded 

case studies, technical reports, and 

best practices guides.

Building America Program

Building America Program • 1-877-EERE-INFO (1-877-337-3463)

Office of Building Technologies, EE-2J • U.S. Department of Energy

1000 Independence Avenue, S.W. • Washington, D.C. 20585-0121

www.buildingamerica.gov

National Renewable Energy Laboratory

www.nrel.gov

Oak Ridge National Laboratory

www.ornl.gov

Pacific Northwest National Laboratory

www.pnl.gov

Produced for the U.S. Department of Energy (DOE) by Pacific Northwest National Laboratory, 

Contract DE-AC05-76RLO 1830.

Research and 

Development of Buildings

Our nation’s buildings consume 

more energy than any other sector 

of the U.S. economy, including 

transportation and industry. 

Fortunately, the opportunities to 

reduce building energy use—and 

the associated environmental 

impacts—are significant.

DOE’s Building Technologies 

Program works to improve the 

energy efficiency of our nation’s 

buildings through innovative new 

technologies and better building 

practices. The program focuses 

on two key areas:

•	 Emerging Technologies

Research and development of 

the next generation of energyefficient components, materials, 

and equipment

•	 Technology Integration of new

technologies with innovative 

building methods to optimize 

building performance and savings

Visit our Web sites at:

www.buildingamerica.gov

www.energystar.gov

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