U.S. Department of Energy

Energy Efficiency and Renewable Energy

Bringing you a prosperous future where energy is clean, abundant, reliable, and affordable

Building Technologies Program

T OF ENERGY

DEPARTMEN

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NITED STAT S OFA ERICA

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Research Toward Zero Energy Homes August 2006 • NREL/SR-550-38783

Building America Residential System Research 

Results: Achieving 30% Whole House Energy 

Savings Level in Cold Climates
Building America Residential 

System Research Results: 

Achieving 30% Whole House 

Energy Savings Level in Cold 

Climates 

January 2005 – November 2005 

Building Industry Research Alliance (BIRA) 

Stockton, California 

Building Science Consortium (BSC) 

Westford, Massachusetts 

Consortium for Advanced Residential Buildings (CARB) 

Norwalk, Connecticut 

Florida Solar Energy Center (FSEC) 

Cocoa, Florida 

IBACOS 

Pittsburgh, Pennsylvania 

National Renewable Energy Laboratory (NREL) 

Golden, Colorado 

NREL Technical Monitors: R. Anderson, R. Hendron, 

M. Eastment, and A. Jalalzadeh-Azar 

Prepared under Subcontract Nos. KAAX-3-32443-07, KAAX-3-33411-07, 

KAAX-3-33412-07, KAAX-3-33410-07 

Subcontract Report 

NREL/SR-550-38783 

August 2006 

National Renewable Energy Laboratory

1617 Cole Boulevard, Golden, Colorado 80401-3393 

303-275-3000 • www.nrel.gov 

Operated for the U.S. Department of Energy 

Office of Energy Efficiency and Renewable Energy 

by Midwest Research Institute • Battelle 

Contract No. DE-AC36-99-GO10337
NOTICE

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Table of Contents 

Table of Contents..........................................................................................................................iii

Definitions..................................................................................................................................... vi

Abstract.......................................................................................................................................... ix

Executive Summary...............................................................................................................................xi

Building America Residential System Research Results: Achieving 30% Whole House Energy 

Savings Level in Cold Climates..................................................................................................... 1

Introduction ............................................................................................................................................1

About Building America ......................................................................................................................................1

Purpose............................................................................................................................................................1

Background .....................................................................................................................................................5

Electronic Reporting of System Research Results ..........................................................................................8

Identification of Component Development Needs..........................................................................................8

Documentation and Resource Development ...................................................................................................9

Building America’s Research Goals....................................................................................................................9

30% Whole-House Energy Savings ..............................................................................................................11

System Approach to Least-Cost Energy Savings...............................................................................................14

Integrated Design Process.............................................................................................................................14

Analysis and Design Optimization................................................................................................................14

Building America Research Benchmark .......................................................................................................15

Analysis Methods..........................................................................................................................................16

Performance Verification ..............................................................................................................................18

System Design and Construction Process...........................................................................................19

Climate Analysis................................................................................................................................................19

Key Climate Elements that Affect Building Design......................................................................................19

Design Strategy Modification for Variances within a Climate Zone ............................................................20

Site Development...............................................................................................................................................21

Orientation Impacts.......................................................................................................................................21

Landscaping ..................................................................................................................................................22

Water Management .......................................................................................................................................22

System Design Approach...................................................................................................................................23

Integrated Design Process.............................................................................................................................23

Energy Analysis ............................................................................................................................................27

Passive Design Strategies for Minimizing Cooling and Optimizing Heating ...............................................28

Indoor Air Quality Strategies ........................................................................................................................31

Heating and Cooling Equipment and Distribution Strategies – Creating Conditioned Space for HVAC 

Systems................................................................................................................................................36

First Costs, Cost Tradeoffs, and Owner Annualized PITI + Energy .............................................................38

Water Management .......................................................................................................................................40

Reducing Construction Waste............................................................................................................................43

Two-foot Module Design ..............................................................................................................................43

Value-Engineered or “Advanced” Framing ..................................................................................................43

Compact Duct Systems .................................................................................................................................47

Recycling of Construction Materials.............................................................................................................48

Quality Project Management Approach.............................................................................................................49

Training/Education........................................................................................................................................50

iii 
Builder and Subcontractor Training ..................................................................................................50

Operational Evaluation..................................................................................................................................52

Performance Standards—Design, Specifications, Scopes.............................................................................53

Verification ...................................................................................................................................................54

Commissioning..............................................................................................................................................56

Feedback Loops.............................................................................................................................................57

Quality-Management Summary ....................................................................................................................57

Building Component Design Details...................................................................................................57

Building Enclosure Integrity ..............................................................................................................................57

Control of Heat Flow.....................................................................................................................................58

Control of Airflow.........................................................................................................................................59

Control of Moisture.......................................................................................................................................61

Specific Recommendations.........................................................................................................................63

Envelope Systems..............................................................................................................................................64

Foundation Systems ......................................................................................................................................64

Building Enclosure Integration Strategies.....................................................................................................66

Space Conditioning and Ventilation Systems....................................................................................................72

Forced Air .....................................................................................................................................................72

Hydronic........................................................................................................................................................73

Ventilation.....................................................................................................................................................73

Air Distribution .............................................................................................................................................74

Dehumidification...........................................................................................................................................77

Mechanical, Electrical, and Plumbing Systems .................................................................................................78

Lighting.........................................................................................................................................................78

Major Appliances..........................................................................................................................................79

Water Heating and Distribution Systems ......................................................................................................80

Combination Systems – Space and Water Heating .......................................................................................83

Onsite Power Systems...................................................................................................................................84

Cost Analysis.........................................................................................................................................84

Life-Cycle Cost Analysis...................................................................................................................................84

First-Cost Impacts..............................................................................................................................................94

Key Cost Tradeoffs .......................................................................................................................................96

Research Results and Conclusions......................................................................................................96

House Case Studies.................................................................................................................... 102

Development: Selkirk Circle Twin Homes.................................................................................102

Development: Magna, Utah .........................................................................................................109

Community-Scale Case Studies................................................................................................. 119

Development: New Homes for South Chicago, Illinois..............................................................119

Development: Foothills at Wingfield...........................................................................................124

Development: Summerset at Frick Park ....................................................................................133

Appendix A: Passive Solar Design Considerations................................................................. 140

Appendix B: Detailed BEopt Analysis Results ........................................................................ 145

Appendix C: List of Key Trade-based Certifications............................................................... 160

Appendix D: National Housing Quality Rating Table ............................................................ 165

iv 
Table D.1. Leadership .......................................................................................................................165

Table D.2. Strategic Planning...........................................................................................................167

Table D.3. Customer Satisfaction.....................................................................................................168

Table D.4. Performance Management.............................................................................................171

Table D.5. Human Resources ...........................................................................................................173

Table D.6. Quality Construction Processes .....................................................................................175

Table D.7. Supplier Partnerships.....................................................................................................177

Appendix E: SNAPSHOT Form .............................................................................................. 183

v 
Definitions 

ACCA Air Conditioning Contractors of America

ACH air changes per hour 

ACT2 Advanced Customer Technology Test for Maximum Energy 

Efficiency 

AFUE Annual Fuel Utilization Efficiency 

AHU air-handler unit 

ALA American Lung Association 

ASHRAE American Society of Heating 

BECT Building Energy Code Training 

BEopt Software for identifying optimal building design 

BESTEST A benchmark for building energy simulation: Building Energy 

Simulation Test a T nd Diagnostic Method 

BII Building Industry Institute 

BPI Building Performance Institute 

CAD computer-aided design 

CDCU Community Development Corporation of Utah 

CEC California Energy Commission 

CFL compact fluorescent bulbs 

CFM cubic feet per minute 

CRI color-rendering index 

CT color temperature 

DHW domestic hot water 

DOE U.S. Department of Energy 

DOE2 Building energy analysis program that can predict the energy 

use and cost for all types of buildings 

ECM electronically commutated motor 

EDHA Eastern Dakota Housing Alliance 

EEBA Energy and Environmental Building Association 

EEM Energy-efficient mortgages 

EER Energy Efficiency Rating 

EF energy factor 

vi 
EFL Environments for Living® 

EGUSA Energy-Gauge USA software (FSEC’s residential front-end 

user interface for DOE2.1E simulation tool) 

EPA U.S. Environmental Protection Agency 

EPS expanded polystyrene 

ERV Energy recovery ventilation 

FF framing factor 

FFA finished floor area 

FG fiberglass 

GenOpt generic optimization program 

HVAC heating, ventilation, and air conditioning 

HERS Home Energy Rating System developed by RESNET 

HPL high-performance lighting 

HRV heat recovery ventilators 

HSPF Heating Seasonal Performance Factor 

HUD U.S. Department of Housing and Urban Development 

IAQ Indoor air quality 

IDEC Indirect-Direct Evaporative Cooler 

IDP Integrated Design Process 

IECC International Energy Conservation Code 

IEQ Indoor Environmental Quality 

IOSEU incremental overall source energy use 

Mcf million cubic feet 

MEC Model Energy Code 

MEF modified energy factor 

MERV Minimum Efficiency Reporting Value 

NAECA National Appliance Energy Conservation Act 

NAHB National Association of Home Builders 

NASEO National Association of State Energy Officials 

NATE North American Technician Excellence 

NHQ National Housing Quality 

NZEH net zero energy home 

OA outdoor air 

vii 
OASys an indirect/direct evaporative cooler 

oc on center 

OSB oriented strand board 

PA Pascal

PATH Partnership for Advancing Technology in Housing 

PEX cross-linked Polyethylene tubing 

PITI principal, interest, tax, and insurance 

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 

SEER seasonal energy efficiency ratio 

SHGC solar heat gain coefficient 

SHW solar hot water 

SLA specific leakage area 

SIP Structural insulated panels

TAB testing, adjusting, and balancing 

TMY2 Typical Meteorological Year weather data 

TOU time of use 

UL Underwriter’s Laboratory 

U-Value The thermal transmittance of a material, incorporating the 

thermal conductance of the structure along with heat transfer 

resulting from convection and radiation. 

UA heat loss coefficient 

VOC volatile organic compounds 

WUFI Modeling program for simulating heat and moisture transfer 

XPS extruded polystyrene 

ZEH zero energy home 

ZNE zero net energy

viii 
Abstract 

The Building America program conducts the system research required to reduce risks associated 

with the design and construction of homes that use an average of 30% to 90% less total energy 

for all residential energy uses than the Building America Research Benchmark, including 

research on homes that will use zero net energy on annual basis. 

To measure the program’s progress, annual research milestones have been established for five 

major climate regions in the United States (Table A). The system research activities required to 

reach each milestone take from 3 to 5 years to complete and include research in individual test 

houses, studies in pre-production prototypes, and research studies with lead builders that provide 

early examples that the specified energy savings level can be successfully achieved on a 

production basis. As additional homes are completed at each performance level, future studies 

will be conducted to confirm the average energy savings of large numbers of homes and the 

impacts of improved housing quality on builder warranty and callback costs. 

Two criteria are used to evaluate progress toward annual Building America research goals: 

1. At a minimum, system energy savings must be achievable at neutral cost relative to the 

Building America Research Benchmark. 

2. System solutions must be “production-ready” and meet minimum constructability, reliability, 

durability, and availability requirements to be implemented successfully by lead builders. 

This report summarizes research results for the 30% energy savings level and demonstrates that 

lead builders can successfully provide 30% homes in the Cold Climate Region on a cost-neutral 

basis. These research results represent the early starting point for the construction of increased 

numbers of high-performance homes. The broad diffusion of 30% homes in the Cold Climate 

Region will depend upon a number of other factors in addition to the research results presented 

in this report, including the level of technical support provided by federal, state, and local 

deployment programs, the consumer cost of energy, and the development of policy incentives 

that support implementation of whole-house residential energy efficiency strategies. 

Table A. Target Energy Savings for Five Major Climate Regions in the United States 

Target 

Energy 

Savings 

Marine Hot Humid Hot-Dry / 

Mixed-Dry 

Mixed 

Humid 

Cold 

30% 2006 2007 2005 2006 2005 

40% 2008 2010 2007 2008 2009 

50% 2011 2015 2012 2013 2014 

ix 
x 
Executive Summary 

Background

Building America uses a team-based systems-research approach to identify cost and performance 

trade-offs that improve whole-building performance and value while minimizing increases in 

overall building cost when applied on a production basis. This systems-research approach is 

applied to the development of advanced energy-efficient residential buildings using systemperformance studies in test houses, pre-production houses, and community-scale developments. 

Research includes analysis of system performance and cost tradeoffs as they relate to wholebuilding energy performance and cost optimization, including interactions between advanced 

enclosure designs, mechanical and electrical systems, lighting systems, space-conditioning 

systems, hot water systems, appliances, miscellaneous electric loads, energy control systems, and 

onsite power generation systems. Research results are documented in technical research reports 

that serve as references for students, educators, building scientists, architects, designers, and 

engineers. 

The overall objective of Building America is to develop integrated energy efficiency and 

onsite/renewable power solutions that can be successfully used on a production basis to reduce 

whole-house energy use in new homes by an average of 50% by 2015 and 90% by 2025 relative 

to the Building America Research Benchmark, including homes that are capable of achieving 

zero net energy (ZNE) use on an annual basis. Building America’s energy-saving goals form the 

core of the research effort and have been staged to complete an additional 10% of incremental 

savings every 3 to 5 years. To ensure meeting the interim targets along the path to Zero Energy 

Homes (ZEH), Building America has specified performance targets for each climate region, as 

shown in Table ES-1. The climate regions defined by Building America can be seen in Figure 

ES-1. Technical performance requirements to meet these targets are driven by regional 

differences in building energy loads and construction techniques. The purpose of this report is to 

provide an overview of three years of Building America systems research that led to the 

development of production-scale homes that can be built cost-effectively and can reduce wholehouse energy use by 30% relative to the Benchmark in the Cold Climate Region. 

Table ES-1. Building America Performance Targets by Climate Region 

Target Energy 

Savings Marine Hot Humid Hot-Dry / 

Mixed Dry 

Mixed 

Humid Cold 

30% 2006 2007 2005 2006 2005 

40% 2008 2010 2007 2008 2009 

50% 2011 2015 2012 2013 2014 

xi 
Figure ES-1. Building America climate regions 

To ensure a well-defined reference for evaluation of energy savings and progress toward multiyear goals, a detailed Benchmark building definition has been developed for use by all 

participants in Building America research projects. The Benchmark is generally consistent with 

the 1999 Home Energy Rating System (HERS) Reference Home, with additions that allow the 

evaluation of all home energy uses. The Benchmark represents typical standard practice in the 

mid-1990s, when DOE initiated the Building America program. A standard reporting format for 

research results has also been developed to facilitate comparisons of performance between 

different research projects. 

Design Strategies 

This report is not intended to be an exhaustive design guide. Rather, the intent is to document 

the results of several years of research on houses that reduce whole-house energy use by 30% 

compared to the Benchmark in Cold climates. Specific design strategies are recommended once 

proven effective and reliable in production housing built by Building America partners. Other 

alternatives may be equally or even more cost-effective depending on the specific housing type, 

micro-climate, risk tolerance, market conditions, and builder cost structure, along with many 

other considerations. 

xii 
To achieve the 30% level of energy savings, it is not necessary to orient homes in any particular 

direction. It is also not necessary to undertake any special passive solar-design strategies, though 

it should be recognized that proper orientation of the building and implementation of passive 

solar strategies can be a low or no-cost method to significantly improve the energy performance 

of a house. 

An Integrated Design Process (IDP) ensures that all the key players and design consultants, 

including the architect, planner, mechanical engineer, landscape architect, energy consultant and 

the site engineer, work together starting with the conceptual design stage, even though the role of 

each may be limited for a particular design stage. The IDP is a key aspect in achieving the 

systems-design approach. By utilizing an IDP, builders are better able to incorporate the 30% 

improvement level strategies with less disruption of their normal construction process and to do 

so cost effectively. Creating specific high-performance goals early in the design process will 

also allow the design and construction team and their external vendors to have a clear 

understanding of the intent and performance metrics associated with the design. 

A key component of high-performance system design and any high-performance construction 

process is quality project management. In the context of Building America high-performance 

homes, quality management is an ongoing effort to systematically and comprehensively improve 

customer-focused satisfaction with emphasis on methods and processes that yield an optimal 

combination of energy efficiency, comfort, durability, indoor air quality, and moisture 

management. This definition recognizes quality management as an integral part of achieving 

30% whole house energy savings, and encompasses homebuyer expectations of performance 

with energy efficiency as just one of several performance attributes that any home should 

provide. 

In high-performance home building, quality is only achieved with performance standards for 

design AND materials (specifications) AND installation (scopes). Building America takes this 

premise one step further by stating that many performance standards must be climate-specific; 

indeed even lot-specific when local terrain and environments bring with them additional 

challenges, such as extreme slopes, expansive soils, coastal high winds and flooding. Training is 

also an essential element of quality in the Building America program. Ongoing efforts within the 

industry are necessary to develop, deploy, and continually update training programs to 

disseminate accurate information. Also important are verification tools for both performance 

and quality, including performance testing and inspection checklists. In general, for production 

builders, Building America has recommended a testing strategy similar to the EPA ENERGY 

STAR® strategy of 1-in-7 random testing after a period of 100% testing to verify that key 

performance metrics are met on a consistent basis. Commissioning is also critical for ensuring 

that the house developed through the whole-building design process is successfully constructed 

and operates as intended. 

In general, Building America houses at the 30% energy savings level in the Cold Climate Region 

include increased levels of thermal insulation, low-e windows, significant air sealing, a strategy 

that eliminates the possibility of introducing the by-products of combustion into the house, a 

mechanical ventilation system, a properly sized and engineered space-conditioning system, 

higher efficiency space-conditioning and water-heating appliances, and may also include 

improvements in the efficiency of the appliances and lighting. The extent to which any of these 

strategies must be implemented varies by the specific micro-climate within the Cold Climate 

Region, and the level of energy performance the builder is seeking to achieve. 

xiii 
In order to function as an environmental separator, the elements, components, assemblies, and 

sub-systems that comprise a house must control the flows of heat, air, rainwater, groundwater, 

and water vapor. 

Exterior walls are usually wood-frame construction with 2x6 framing and cavities insulated with 

fiberglass batts, spray-applied cellulose, or low-density spray-applied foams. The 2x4 framing 

may also be acceptable in parts of the Cold Climate region when used with insulating sheathing. 

However, insulating sheathing of sufficient thickness moves the condensation temperature out of 

the framing and allows the removal of interior vapor barriers and increasing the permeability of 

vapor retarders, thereby enhancing the inward drying capability of the assembly and reducing the 

likelihood of moisture problems. An interior vapor diffusion retarder with permeability less than 

1 perm is recommended if insulating sheathing is not used. Fenestration with a maximum 

U-value of 0.35 and with a SHGC value of 0.4 or lower is recommended, primarily for comfort 

reasons. An interior air barrier is necessary and is most cost effectively obtained using interior 

gypsum sheathing combined with framing elements, such as draft-stopping and fire-stopping 

components. Installing both interior and exterior air-barrier systems can address the weaknesses 

of each. The air leakage target should be less than 2.5 in.2 per 100 ft2 of thermal envelope area. 

The approach to rainwater control is to shed water by layering wall materials in such a way that 

water is directed downward and outward from the building. This principle applies not only to 

walls, but to assemblies such as roofs and foundations, as well as to the components that can be 

found in walls, roofs, and foundations such as windows, doors, and skylights. 

When using slab-on-grade construction in Cold Climates, it is recommended that the concrete 

slab be thermally isolated from the ground and outdoor air. Passive sub-slab ventilation is 

recommended to reduce atmospheric air pressure soil gas drivers. Crawlspaces may be 

conditioned by insulating the crawlspace walls and supplying conditioned air either via a 

dedicated duct or via transfer air from the house with a continuously operating exhaust fan in the 

crawlspace. Alternatively, crawlspaces may be vented and insulated above the crawlspace as 

long as any ducts located in the crawlspace are well-sealed and insulated. The recommended 

approach for basements includes insulating and conditioning the basement. Interior rigid foam 

insulation is the insulation system of choice for both basement and crawlspace walls because it is 

not water sensitive. 

As long as there is no ductwork planned for the attic space, the optimum approach to roof 

insulation involves blowing insulation on the top surface of ceiling gypsum board. Roof trusses 

should be constructed in such a manner such that the full thickness of ceiling insulation is 

maintained completely to the top plates of the exterior wall framing. It is recommended that all 

ductwork be placed in conditioned space; however, if there is ductwork in the attic space, the 

ducts should be buried under the insulation to minimize air leakage and thermal losses from the 

ductwork. 

To accomplish the target of 30% whole-house energy savings in the Cold Climate region, a 

sealed-combustion condensing furnace is recommended. Sealed-combustion furnaces use 

outdoor air for combustion and can be easily located within the conditioned space. In regions 

where natural gas is not available, a high efficiency electric heat pump is recommended. 

30% performance goal is generally achievable by applying air conditioners that meet the 

minimum 2006 federal (NAECA) standard of 13 SEER. This is particularly true if efficient duct 

systems are employed and if cooling loads are reduced by incorporating high performance (Lowxiv 
E2) windows and architectural window shading in the design. However, it should be noted that 

there is a wide range of cooling requirements in the Cold climate region, and the SEER rating 

should be evaluated based on annual hours of operation. In general, the greater the cooling need, 

the higher the SEER rating should be. Designers also need to check the mean coincident wetbulb temperature at outdoor design conditions and select equipment based on this. This strategy 

helps to prevent oversizing of the equipment. All space heating and cooling systems should be 

sized according to the procedures described in ACCA Manuals J and S. 

It is recommended that all ductwork to be located within the thermal envelope of the house. 

Methods for locating the duct system within the conditioned space include the use of open-web 

floor trusses, dropped ceilings and soffits, interior chase walls with duct risers (exterior walls 

should not be used as chase walls), modified roof trusses, or an unvented or “cathedralized” attic. 

The “best” method for locating ducts in conditioned space depends upon the house plan, the type 

of foundation, and the builder’s preferences. The ducts may also be buried in attic insulation. 

Central hard-ducted returns are recommended with passive return air paths such as jump ducts or 

transfer grilles from bedrooms. If ducts cannot be brought within conditioned space, supply 

ducts should be insulated to R-8 minimum and return ducts to R-4 minimum. 

Furnaces or air handlers with “variable-speed” brushless permanent magnet (BPM) DC motors 

are recommended. These motors are more efficient at lower speeds than the more common 

permanent split-capacitor (PSC) type motors. Efficiency at lower speed operation is increasingly 

important for systems that feature multiple gas firing stages, enhanced dehumidification 

capability during cooling, air cleaning equipment, or integrated ventilation. 

Providing good indoor air quality (IAQ) at the 30% improvement level is important to maintain 

occupant health and comfort and may minimize the possibility of high humidity levels and 

associated mold growth. Because 30% houses will have higher levels of insulation (which affects 

enclosure hygrothermal characteristics) and because they will be reasonably air tight (which will 

affect internal moisture gain and removal), good IAQ requires a more proactive approach. There 

are several approaches to good IAQ, including control of pollutant-generating sources, removal 

of the contaminants from the indoor air by ventilation, and air filtration or cleaning. A whole 

house mechanical ventilation system is recommended, such as an exhaust-only system rated for 

continuous duty, a supply-only system integrated with the central air-handling unit or a heatrecovery ventilator. 

For high-performance, low-sensible-heat gain homes, there may be a need for supplemental 

dehumidification during the mild swing seasons and at night. However, houses in the Cold 

Climate are less likely to require supplemental dehumidification, Because the outdoor air 

dewpoint is almost always at or below a comfortable interior level. In this case, outdoor 

ventilation air can be used to dilute interior moisture without the need for separate 

dehumidification. 

Tankless water heaters offer the best efficiency for domestic water heating within the Cold 

Climate region. If electricity is the energy source for water heating, additional improvements to 

other areas of the house will likely be needed to achieve the 30% savings levels, because there is 

very little room for improvement in electric water-heating efficiency compared to the possible 

efficiency gains using gas-fired technologies. . 

Simple screw-in CFL substitution is a viable strategy at the 30% level; however, there are 

questions as to the persistence of energy savings because the homeowner is free to replace the 

xv 
CFL with a traditional incandescent light bulb. A High-Performance Lighting (HPL) approach 

using a full complement of hard-wired, dedicated compact and linear fluorescent fixtures does 

not appear to be cost effective for a house at the 30% improvement level. 

At the present time, the best practice recommendation for the 30% improvement house is to use 

ENERGY STAR-rated appliances. Within the ENERGY STAR-rated offerings, there are 

differences in performance levels, but these are probably not of significance at the 30% 

improvement level. 

At the 30% energy savings level, it is not required to address the miscellaneous electric load 

(MEL) category. 

On-site power systems such as photovoltaic systems and fuel cells are very costly and are not 

cost effective as a strategy to achieve the 30% energy savings level. 

All of these systems must be properly designed and applied to realize both energy-related and 

non-energy performance benefits associated with occupant health, safety, comfort and long-term 

building durability and efficiency. 

One of the key challenges in developing best practice recommendations is to develop an 

approach that quickly focuses on combinations of measures that represent the least-cost solutions 

for a given level of energy savings. To address this challenge, NREL has developed an iterative 

trade-off analysis method, which identifies packages of energy efficiency measures that provide 

energy savings at an annual cost that is less than or equal to the utility cost for a reference house 

when energy improvements are financed as part of a 30-year mortgage. 

Use of this method of analysis for one- and two-story homes in Chicago helps to identify the 

trends that result in a home that saves 30%-39% whole-house energy relative to the Benchmark. 

The results suggest that several envelope, mechanical equipment duct and lighting improvements 

are necessary to meet the 3% savings level in Chicago. A tight envelope and R-19 walls, R-40 

ceiling insulation, low-e windows, gas-tankless water heater, and a condensing furnace combined 

with ducts inside conditioned space, appear to be sufficient. At the 39% level higher SEER air 

conditioning systems, additional basement insulation and efficient appliance measures may be 

needed. Of course other considerations, such as durability, comfort, aesthetics, and health, are 

also important, but cannot be easily addressed in an automated optimization program. 

Through the use of systems engineering and operations research, the Building America program 

has shown that homes that save 30% whole-house source energy in Cold Climates can be built 

on a cost-neutral basis by production builders while improving comfort, reliability, durability, 

and indoor air quality. A series of five case studies are presented in this report, documenting 

some of the important cost and performance trade-offs that were made by Building America 

builder partners in order to achieve the 30% energy-savings target in a production context. 

While the specific combinations of technologies described in this document may not represent 

cost-optimal solutions for all areas and housing types covered by the Cold Climate, the key 

features of the approaches demonstrated in each of these examples can be adapted as needed to 

provide homes that achieve at least 30% whole-house energy savings in a cost-neutral manner. 

xvi 
Building America Residential System Research Results: 

Achieving 30% Whole House Energy Savings Level in Cold Climates 

Introduction 

About Building America 

Purpose 

The objective of the Building America Program is to develop innovative system-engineering 

approaches to advanced housing that will enable the housing industry in the United States to 

deliver energy-efficient, affordable, and environmentally sensitive housing while maintaining 

profitability and competitiveness of homebuilders and product suppliers in domestic markets. 

For innovative building energy technologies to be viable candidates over conventional 

approaches, it must be demonstrated that they can cost-effectively increase overall product value 

and quality while significantly reducing energy use and use of raw materials when used in 

community-scale developments. To make this determination, an extensive, industry-driven, 

team-based, system-engineering research program is necessary to develop, test, and design 

advanced-building energy systems for all major climate regions of the United States in 

conjunction with material suppliers, equipment manufacturers, developers, builders, designers, 

and state and local stakeholders. 

Building America research results are based on use of a team-based systems-research approach, 

including use of systems-research techniques1

 and cost and performance trade-offs that improve 

whole-building performance and value while minimizing increases in overall building cost. 

Figure 1 shows the Building America system-research approach in its most basic form. Building 

America is an analysis-focused research program that specifically targets technical barriers that 

limit residential system energy performance. Building America applies system research 

approaches to the development of advanced energy-efficient residential buildings using systemperformance studies in test houses, pre-production houses, and community-scale developments. 

Research includes analysis of system performance and cost tradeoffs as they relate to wholebuilding energy performance and cost optimization, including interactions between advanced 

envelope designs, mechanical and electrical systems, lighting systems, space-conditioning 

systems, hot water systems, appliances, plug loads, energy-control systems, and onsite power 

generation systems. Use of a systems approach creates process innovations that improve 

efficiency and flexibility of housing production and increase control over component interactions 

that improve house efficiency and performance. 

Use of a systems approach also accelerates adoption of new technologies by increasing 

integration between the design and construction process, increasing system performance, 

increasing system cost effectiveness, and increasing system reliability and durability. 

Community-scale evaluation of advanced system concepts in partnership with builders, 

contractors, and state and local governments provides opportunities for early adopters and 

 

1

 Systems Research is research focused on understanding cost, performance, and reliability interactions between 

different system components. 

1 
Design

Test Houses 

Figure 1. Overview of Building America’s systems-engineering approach. The 

development of production-ready results covering the range from test houses to 

community-scale housing takes 3 to 5 years. 

industry leaders to directly contribute to key results from the research program. A systems 

approach for development of advanced residential buildings is defined to be any approach that 

utilizes comprehensive examination and analysis of overall design, delivery, business practices, 

and construction processes, including financing, and that performs cost and performance 

tradeoffs between individual building components and construction steps that produce a net 

improvement in overall building value and performance. A systems approach requires integrated 

participation and team building among all interested parties in the building process including 

developers, architects, designers, engineers, builders, equipment manufacturers, material 

suppliers, community planners, mortgage lenders, state and local governments, utilities, and 

others. 

The final products of each Building America research project include performance 

measurements and cost/performance evaluations in test houses, pre-production homes, and 

community-scale developments. These measurements and evaluations lead to development of 

innovative system concepts that can be applied on a production basis by the industry partners and 

stakeholders involved in the program. The range of innovative system concepts considered in 

projects include onsite power systems, innovative envelope systems, advanced mechanical and 

lighting systems, advanced space-conditioning systems, efficient water-heating systems, 

renewable energy systems, efficient appliances, energy-control systems, and design and 

Community-scale 

Housing 

Pre-production Houses 

Build

Test 

Re-design 

Cost and Performance Trade-offs 

Accelerate Development of 

Advanced Energy Systems

2 
construction strategies. Performance results from the evaluation of these systems are presented 

to a broad residential building science audience via development of technical papers, the 

Building America Web site, and presentations at major building-industry conferences. 

Building America industry teams and team leads continuously evolve and increase the partners 

and stakeholders that participate in their projects so that the number of buildings and systems 

influenced by the program continues to grow over time. 

The overall objective of the Building America research program is to develop integrated energy 

efficiency and onsite/renewable power solutions that can be successfully used on a production 

basis to reduce whole-house energy use in new homes by an average of 50% by 2015 and 90% 

by 2025, relative to the Building America Research Benchmark,2 including homes that are 

capable of achieving zero net energy (ZNE) use on an annual basis. 

The key system research questions addressed by Building America research teams include the 

following: 

• Evaluation of overall system cost tradeoffs relative to current systems. What are the system’s 

incremental costs and how will the system affect overall building costs? 

• Evaluation of overall system benefits relative to current systems. What overall value is 

delivered by the system to builders? To contractors? To consumers? (Examples of system 

benefits include utility bill savings, contribution to whole-house energy-savings goals, 

increased durability, reduced warranty and callback costs, increased comfort, reduced 

construction waste, increased labor productivity, increased water efficiency, increased safety 

and health, reduced peak loads) 

• Evaluation of the expected market impact of new residential energy systems. What fraction 

of the residential housing market will be directly affected by research results? What are 

barriers to broad market use? What research can be done to reduce barriers to broad use? 

• Evaluation of the constructability of new residential energy systems. What are barriers and 

risks associated with the use of new systems? Can results be implemented on a production 

basis? What additional research is required to develop a clear description of whole-house 

system-performance requirements and key system-design details that minimize barriers and 

risks and maximize benefits? 

• Evaluation of the potential community-scale benefits of advanced residential energy systems. 

What additional benefits will result when systems are implemented on a community scale? 

Taken together, these research questions frame the overall difficulty of resolving the risks 

associated with use of advanced energy systems, help to define the systems research required to 

integrate new systems seamlessly into a production construction process, and emphasize the 

importance of documenting the performance benefits of advanced systems. 

Construction of new homes requires the combined efforts of a large number of suppliers and 

contractors whose efforts are coordinated by a large number of builders. Because of the high 

 

2

 Hereafter in this report referred to as the Benchmark. Hendron, R. 2005. Building America Research Benchmark 

Definition, Updated December 29, 2004. NREL/TP-550-37529. Golden, CO: National Renewable Energy 

Laboratory. 

3 
01234567

US Homebuilding

US Wood Products

US Housing Products

US (Composite)

Foreign (Composite)

Japan (Composite)

Percentage of Sales

Figure 2. Research and Development expenditures3

cost of failure, the residential construction industry is highly risk-intolerant and first-cost 

sensitive. Development of new systems and corresponding changes in design and the relatively 

low level of R&D investment further complicate construction practices by the housing industry. 

Figure 2 compares R&D expenditures for various residential markets. The key market barriers 

to development of advanced residential energy systems are the large number of market players, 

the relatively low level of investment in R&D relative to other sectors of the economy, and strict 

requirements for market acceptance based on achievement of low incremental costs and high 

reliability. 

The key technical barriers to the development of advanced residential energy systems are the 

large number of technical performance requirements that must be met before a new system can 

be implemented on a production basis. These technical performance requirements are driven by 

regional differences in building energy loads and construction techniques. Systems that work 

well in Cold Climates may not be applicable in Hot Climates. Systems that work well in Hot-Dry 

Climates may not function well in Hot-Humid Climates. 

A recent study by the RAND Corporation for HUD’s Partnership for Advancing Technology in 

Housing (PATH), entitled Building Better Homes: Government Strategies for Promoting 

Innovation in Housing4

, concludes that, 

... the housing industry is large and complex, involving many public and private 

entities. The interests, roles, and capacities of each participant and the 

relationships they share have shaped the housing industry into what it is 

today...Instead of trying to identify barriers and asking the industry to change 

itself (or asking the government to change it), this study seeks to identify options 

to accelerate innovation within the housing industry as it exists today. It begins by 

 

3

 The United States homebuilding industry invests 0.25% of sales in research compared to $3.8% for all market 

sectors (Business Week R&D Scoreboard, June 28, 1993). 

4

 RAND, Building Better Homes: Government Strategies for Promoting Innovation in Housing, 2003. 

4 
critically examining the concept of innovation and how it might be better 

understood within the context of the housing industry. What results is a departure 

from the linear model of innovation that assumes logical and unidirectional 

movement from research to development, demonstration, and deployment to one 

that recognizes much greater interactive dynamics in the innovation process. 

Research in this model is a base for knowledge, which contributes to invention, 

development, demonstration, and deployment. Moreover, all these activities or 

stages in the innovation process are affected by market forces.”

Because of the strong interaction between technical and market barriers, a linear research 

approach that begins with basic R&D and ends with technology deployment is not likely to be 

successful when applied to residential systems. A market-driven, system-based research 

approach can provide valuable benefits to builders, consumers, and utilities while simultaneously 

resolving market and technical barriers to innovation.

Pulte Homes Southwest Division has used technical assistance from the U.S. Department of 

Energy’s (DOE) Building America program to create what one residential expert calls “the best 

production house in the world,” which won the 2001 National Association of Home Builders’ 

Energy Value Housing Award. In Tucson, Phoenix, and Las Vegas, Pulte Homes has worked 

with the DOE to redesign the energy features of its basic models. Using advanced insulation 

techniques, highly efficient equipment and windows, and right-sized heating and cooling 

systems, the homes look the same, but perform so well that they use half the energy for heating 

and cooling at virtually no increase in construction costs. The whole-building/systems 

engineering approach used in the Building America program allows builders to add more 

insulation and more efficient windows while reducing the size of the heating and cooling 

equipment. The trade-off means no added cost to the builder, better value for the buyer, reduced 

electric load for the utility and improved affordability.

Background 

Building America was started in 1995 to conduct the systems research required to develop 

residential energy efficiency solutions that achieve 30%-100% savings when used on a 

production basis by builders of new homes. The long-term 2025 research goal for the program is 

to develop cost-effective system designs that can result in Net Zero Energy Homes (NZEH).5

 In 

the past 10 years, Building America has made significant progress on the path to NZEH, 

including the completion of more than 30,000 homes. 

Building America research participants have developed an in-depth systems research process by 

combining operations research6

 and systems engineering.7 The first step of the systems-research 

process is to use operations research techniques to identify the technology pathways that will 

achieve the target energy savings in each region for the lowest potential installed cost. From 

these results, the optimal efficiency targets can be identified and technologies can be developed 

 

5

 A net zero energy house is a house that produces as much energy as it uses on an annual basis through integration 

of energy efficiency solutions and onsite power systems. 

6

 Operations Research is research aimed at understanding the best way to operate a system to maximize 

performance, based on system constraints. 

7

 Systems Engineering is engineering based on knowledge from systems research aimed at maximizing the 

performance and durability of a system, subject to operating constraints. 

5 
that will meet the energy-savings needs cost effectively in all climate regions. The second step 

in the systems research is to implement the optimal technology pathways through systems 

engineering in homes. The systems-engineering step will identify challenges and barriers 

unanticipated by the optimization. The combination of operations research and systems 

engineering ensures that the solutions created meet the energy savings and cost goals and can be 

used on a production basis. Figure 3 shows a more detailed look at the Building America 

systems research approach (Table 1). 

Fail / Pass 

Phase 2: Prototype 

House Evaluations 

Phase 3: Community-Scale 

Evaluations 

System Research

Completion Reports 

Development of Advanced

Components

(BT Emerging Technologies, 

Manufacturers, Other EERE 

Offices) 

Phase 1: System 

Performance 

Evaluations 

Pre-phase: Gap 

Analysis, Planning 

and Coordination 

Reject 

Post-phase:

Documentation 

and Resource 

Development

Reject 

Handoff to 

Deployment 

Partners

Go/No-Go Decision Point:

Initiation of System 

Research 

Fail / Pass 

Reject Fail / Pass 

Reject Pass / Fail 

Figure 3. A more detailed look at the Building America system research strategy 

6 
Table 1. Building America Background 

Start date 1995 

Target market(s) New, single-family residential buildings 

Accomplishments to date 1. Developing the Benchmark Definition 

2. Developing protocols for validating whole-house 

energy performance 

3. Documenting research and publishing Houses

That Work, Builder Guides, and Best Practices 

4. Increasing the number of ENERGY STAR®

homes 

Current activities Developing integrated cost-effective, whole-building 

strategies to enable new, single-family residential 

buildings to use 30% less total energy than the 

Building America Benchmark in the Cold and HotDry/Mixed-Dry Climate regions. 

Future directions Continuing to develop the strategies for new, singlefamily residential buildings to use 40%-100% less 

energy than the Benchmark in the Marine, HotHumid, Hot-Dry/Mixed-Dry, Mixed-Humid, and Cold 

Climate regions 

Projected end date(s) 2025 

The systems research is applied in three phases for each climate zone. During the three phases, 

which are conducted in parallel to allow feedback between phases, Building America acts as a 

national residential energy systems test bed where homes with different system options are 

designed, built, and tested at three levels of system integration, including research houses, 

production prototype houses, and evaluations in community-scale housing to validate the 

reliability, cost effectiveness, and marketability of the energy systems when integrated in 

production housing. After completion of the community evaluations, a low level of technical 

support may be provided as needed to ensure successful implementation of system research 

results at each performance level targeted by the program. A detailed summary of the three 

phases of the system research process is captured in Table 2. 

The three system-engineering stages overlap one another to allow issues to be quickly resolved 

as they are identified. The three system-research stages currently take about 3 to 4 years, but for 

more advanced energy efficiency levels at and above 40% whole-house savings, the systems7 
Table 2. Residential Integration Systems Research Approach 

Phase 1 – System Evaluations 

In Phase 1, the Building America Consortia design, construct, and test subsystems for 

whole-house designs in research houses to evaluate how components perform. The 

focus of Phase 1 is to evaluate and field-test prototype subsystems to determine the 

most reliable and cost-effective solution for a given performance level and climate. 

Phase 2 – Prototype Houses 

In Phase 2, the successful Phase 1 subsystems are designed and constructed by 

production builders working with the Building America Consortia to evaluate the ability to 

implement the systems on a production basis. The focus of Phase 2 research is to 

move the research prototype house and building practices to the point that they are 

production-ready and capable of being integrated with production construction 

techniques practiced by today’s builders. 

Phase 3 – Community Evaluations 

In Phase 3, the Building America Consortia provide technical support to builder partners 

to advance from the production prototypes to evaluation of production houses in a 

subdivision. The results are documented in a case-study report. Several of these 

reports are distilled into a final research report that describes the system design and 

construction practices needed to achieve a particular level of energy savings within each 

climate zone targeted by the program. 

research process is expected to take additional iterations of whole-house testing before 

implementation in production ready homes. At the 50% whole-house level and above, the 

system research stages are expected to take 4 to 5 years to complete. 

Electronic Reporting of System Research Results 

Final research results from the program are reported electronically via the Building America 

Website (www.buildingamerica.gov). Research results include project data, research reports, 

case studies, research highlights, and background information on the research program and its 

participants. The website also includes a document database and reference materials on the 

performance analysis and measurement procedures. 

Identification of Component Development Needs 

The three-phase systems-engineering approach (Table 2) requires identification of future system 

needs to allow the lead time required to develop and evaluate options to meet those needs. 

Before initiation of Phase 1 studies in research houses, components must be developed and 

evaluated to determine their potential to fill gaps between the performance of current systems 

and future whole-house performance goals. The component research requires significant lead 

time in some cases and focuses on communication of system-integration needs and requirements 

to component developers. Building America’s role is to provide inputs to component developers 

that help to identify residential system integration needs, requirements, and gaps based on annual 

8 
residential cost/performance studies using the BEopt analysis method.8

 Components must be 

developed for Phase 1 and have to meet minimum requirements for energy performance, 

reliability, and cost effectiveness before they are included as part of the residential integration 

activities in Phases 2 and 3. 

Documentation and Resource Development 

At the completion of Phase 3, the research results are documented in technical research reports 

that serve as references for students, educators, building scientists, architects, designers, and 

engineers. For the research results to be successfully transferred to additional important 

participants in the housing industry, they must be translated into a format appropriate for 

dissemination to developers, builders, contractors, homeowners, realtors, insurance companies, 

and mortgage providers. 

This post-Phase-3 activity of the DOE fosters movement of the research and building techniques 

of the Building America Program to the market and establishes voluntary collaborations with 

housing and financial industries to make the nation’s houses more energy-efficient and 

affordable. This final stage of the process focuses on documentation of best practices and 

development and evaluation of resources to hand-off DOE building-research findings to private 

and public sector implementation programs. This work supports activities that improve the 

energy efficiency of public and privately owned single-family housing. The program 

coordinates presentations at technical conferences on peer-reviewed, validated, research results 

and facilitates validation, field-testing, and evaluation of the post-phase-3 documentation. 

The Building America resource development effort creates “Best Practices” manuals from the 

Phase-3 research reports that are designed for builders, manufacturers, homeowners, realtors, 

educators, insurance companies, and mortgage providers. The Best Practices manuals 

summarize best-practice recommendations in illustrated text that is targeted to a specific 

audience to make it easily assimilated and that synthesize research findings into energy-efficient 

processes for the building industry. To facilitate construction of affordable homes designed for 

non-profit organizations and small builders, Building America plans to make floor plans and 

section details available through the web and other means. 

Building America’s Research Goals 

Building America’s energy-saving goals form the core of the research effort and have been 

staged to complete an additional 10% of incremental savings every 3 to 5 years (Table 3). 

To ensure meeting the interim targets along the path to Zero Energy Homes (ZEH), Building 

America has also specified the interim performance targets for each climate region (Table 4). 

 

8

 BEopt stands for “Building Energy Optimization Analysis Method,” as defined in “Analysis of System Strategies 

Targeting Near-Term Building America Energy-Performance Goals for New Single-Family Homes,” Anderson, Ren 

et al. November 2004, NREL/TP-550-36920. 

9 
Table 3. Building America Research Goals9

Year 

Characteristics Units 

2007 2010 2015 2020 2025 

Average Source Energy Savings % 30 40 50 70 90 

Cost $ Zero or Less Net Cash Flow10

Table 4. Building America Performance Targets by Climate Region 

Target 

(Energy 

Savings) 

Marine Hot Humid Hot-Dry / 

Mixed Dry 

Mixed 

Humid Cold 

30% 2006 2007 2005 2006 2005 

40% 2008 2010 2007 2008 2009 

50% 2011 2015 2012 2013 2014 

In addition to energy savings, Building America has additional system-performance goals that 

are critical to the success of the systems research process. These include the following: 

• Accelerating the development and implementation of advanced-energy systems in new and 

existing residential construction through application of systems-engineering research projects 

by cross-cutting industry teams 

• Reducing residential building construction site waste, increasing the use of recycled 

materials, reducing construction cycle time, increasing system durability and reliability, and 

reducing warranty and call-back costs 

• Developing innovative technologies and strategies that enable the housing industry in the 

United States to deliver environmentally sensitive, quality housing on a community-scale 

while maintaining profitability and competitiveness of homebuilders and product suppliers 

• Increasing housing value and affordability for homeowners in the United States. 

 

9

 Year of completion of annual performance targets in six climate regions. Energy savings are measured relative to 

Benchmark. The targets in Table 4 are updated on an annual basis dependent on technical progress and funding. 

10 Life cycle cost, see TP-550-37529. 

10 
11 

30% Whole-House Energy Savings 

Building America’s current research activities target 30% total energy savings in new singlefamily homes in six climate regions. Residential buildings include a limited number of different 

end uses with many similarities in a particular climate region. Therefore, a climate region 

approach is appropriate because residential system solutions can be easily replicated on a 

regional basis. The climate regions defined by Building America can be seen in Figure 4. 

Because of limited resources, Building America is targeting six of the eight climate regions, 

including Marine, Hot-Humid, Hot/Mixed-Dry, Mixed-Humid, and Cold. The Hot-Dry and 

Mixed-Dry Climates have been combined into a single climate target for Building America 

planning purposes because of the similarities of the solutions for the two climates. The severe 

Cold and Subarctic Climate regions have been omitted because of limited resources and the lack 

of residential growth in those regions.
Figure 4. Building America climate regions 

12 
0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

500,000

Mixed Humid Cold Hot Humid Hot/Mixed Dry Marine

New Homes

0

10

20

30

40

50

60

70

80

90

Builder Partners

New Homes Builder Partners

Figure 5. New homes 11 and builder partners12 by climate region 

From 2003 to 2005, Building America has developed the following solutions to use 30% less 

total energy than the Building America Benchmark for the Hot-Dry/Mixed-Dry and the Cold 

Climate regions. These climate regions present opportunities for research because of the number 

of new homes being built and the relationships established with builder partners. The number of 

new homes and builder partners for each climate region can be seen in Figure 5. Building 

America will focus on developing the 30% solutions for the Mixed-Humid and Marine regions in 

2006. 

Through 2025, Building America will continue to develop the strategies for new, single-family 

residential buildings to use 30%-100% less total energy in the Marine, Hot-Humid, Hotdry/Mixed-Dry, Mixed-Humid, and Cold Climate regions over the full range of house sizes, 

styles, and price points. 

The purpose of this report is to provide an overview of 3 years of Building America system 

research that led to the development of homes that save 30% relative to the Benchmark.13 Based 

 

11 July 1, 2002, to July 1, 2003. U.S. Census Bureau Housing Unit Estimates (HU-EST2003-04), "Annual Estimates 

of Housing Units for Counties: April 1, 2000, to July 1, 2003," Last revised September 2, 2004. 

12 “House Counts by Climate Zone (detailed)”, U.S. Department of Energy, Building America House Performance 

Database, January 5, 2005. 

13 The Research Benchmark provides a detailed description of all residential energy uses and serves as the reference 

point for the energy savings goals in Building America research project. More information about the Benchmark can 

be found on the Building America website: 

http://www.eere.energy.gov/buildings/building_america/pa_resources.html. 

13 
on the research results and case studies included in this report, the Building America Research 

teams have demonstrated that 30% homes can be reliably designed and constructed by 

production builders in Cold Climates. The actual rate of adoption of the research results 

contained in this report will depend upon a number of factors, including residential energy costs 

and national, state, and local incentives for the use of energy-efficient construction techniques. 

System Approach to Least-Cost Energy Savings 

Integrated Design Process 

Building America's team-based systems-research approach, including use of systems-engineering 

and operations research techniques, provides opportunities for cost and performance trade-offs 

that improve whole-building performance and value, while minimizing increases in overall 

building cost. Systems engineering is conducted at multiple scales, including individual test 

houses, pre-production houses, and community-scale developments. Systems research includes 

analysis of system performance and cost tradeoffs as they relate to whole-building energy 

performance and cost optimization, including interactions between advanced envelope designs, 

mechanical and electrical systems, lighting systems, space-conditioning systems, hot water 

systems, major appliances, miscellaneous electric loads, energy control systems, renewable 

energy systems, and onsite power generation systems. Accordingly, the best practice 

recommendations in this report have been demonstrated to cost-effectively increase overall 

product value and quality compared to conventional approaches, while significantly reducing 

energy use and use of raw materials when used on a production basis. 

The final products of each research project include performance measurements and 

cost/performance evaluations in prototype houses, pre-production homes, and community-scale 

developments, and climate-based system research design/technology packages, including system 

performance specifications. These measurements, evaluations, and system-performance packages 

are the basis of the recommendations provided in this report. 

Analysis and Design Optimization 

The research path to future residential energy savings extends from a base case (e.g., a currentpractice building, a code-compliant building, or some other reference building) to a ZNE 

building with 100% energy savings. To ensure a well-defined reference for evaluation of energy 

savings and progress toward multi-year goals, a detailed Benchmark14 building definition has 

been developed for use by all participants in Building America research projects. A standard 

reporting format for research results has also been developed to facilitate comparisons of 

performance between different research projects. 

The Benchmark is generally consistent with the 1999 Home Energy Rating System (HERS) 

Reference Home, as defined by the National Association of State Energy Officials/Residential 

Energy Services Network (NASEO/RESNET), with additions that allow the evaluation of all 

home energy uses. The Benchmark represents typical standard practice in the mid-1990s, when 

DOE initiated the Building America program. Additional documentation to support the use of 

 

14 Hendron, R. 2005. Building America Research Benchmark Definition, Updated December 29, 2004. NREL/TP550-37529. Golden, CO: National Renewable Energy Laboratory. 

14 
the Benchmark, including spreadsheets with detailed hourly energy usage and load profiles, can 

be found on the Building America Web site.15 As Building America teams develop innovative 

new technologies and systems approaches that move the program toward its research goals, the 

Benchmark will be re-evaluated and refined periodically to ensure that energy savings from these 

features are accurately credited. Many other valid techniques and definitions have been 

developed by other organizations, and they can be very useful to builders for specialized 

applications. For example, the HERS rating procedure (RESNET 2002) must be followed to 

obtain an ENERGY STAR® rating for building energy efficiency. Also, it might be necessary to 

determine whether or not a Prototype meets the International Energy Conservation Code 

(IECC)16 or Model Energy Code (MEC),17 which could apply if adopted by the state or local 

government. 

Building America Research Benchmark 

The Benchmark was developed to track and manage progress toward the Building America 

multi-year whole-building energy savings goals for new construction, using a fixed reference 

point. To provide a context for the potential impacts of research projects on local and regional 

markets at a given point in time, energy usage is also compared with current Regional Standard 

Practice and Builder Standard Practice. Standard occupant profiles for use in conjunction with 

these reference houses have also been developed based on review of the available literature; the 

intent is to represent typical occupant behavior. Additional analysis and end-use monitoring18

are required to evaluate energy savings for specific occupants whose individual behavior could 

vary from the average profiles defined in the Benchmark. In general, relative savings for an 

individual user are expected to be approximately the same as those for an average user. 

Energy savings can be defined in terms of site energy (used at the building site) or source energy 

(sometimes called primary energy). For electricity purchased from a utility, site energy can be 

converted to source energy to account for power plant generation efficiency and electrical 

transmission and distribution losses. The source-to-site energy ratio for electricity typically has a 

value of about 3, depending on the mix of electrical generation types (coal-fired, natural gas 

combined cycle, nuclear, hydropower, etc.). For the purpose of Building America analysis, 

national average site-to-source multipliers of 3.16 for electricity, 1.02 for natural gas, and 1.00 

for all other fuels are used. From the view of all stakeholders in the building process, site and 

source energy are both important. Source energy has been chosen as the basis for tracking 

progress toward the Building America energy-saving targets and is also used as the basis of the 

cost/performance tradeoffs analyzed in this report. Site energy savings are also calculated as part 

of ongoing research projects and included in project evaluations because of their importance in 

determining specific utility bill savings. 

 

15 www.eere.energy.gov/buildings/building_america/pa_resources.html. 

16 International Energy Conservation Code®: 2003 Edition with 2004 Supplement. Country Club Hills, IL: 

International Code Council, Inc. 2003, 2004. 

17 MEC 1995, Council of American Building Officials (CABO) 5203 Leesburg Pike, Falls Church, VA 22041. 

18 Norton, P.; Hancock, E.; Barker, G.; Reeves, P. et al. 2003. The Hathaway “Solar Patriot” House: A Case Study in 

Efficiency and Renewable Energy. NREL/TP-550-37731. Golden, CO: National Renewable Energy Laboratory. 

15 
Analysis Methods 

A key issue in any building energy analysis is which tool or program to choose to estimate 

energy consumption. An hourly simulation is often necessary to fully evaluate the timedependent energy impacts of advanced systems used in Building America houses. Thermal 

mass, solar heat gain, and wind-induced air infiltration are examples of time-dependent effects 

that can be accurately modeled only by using a model that calculates heat transfer and 

temperature in short time intervals. In addition, an hourly simulation program is also necessary 

to accurately estimate peak energy loads. Because of the large number of users, public 

availability, and level of technical support, DOE-2 is the most commonly used hourly simulation 

engine for systems analysis studies performed under the DOE Building America program. 

EnergyGauge19 is a frequently used interface for DOE-2; it has been tailored specifically to 

residential buildings. EnergyGauge can also automatically calculate HERS scores and evaluate 

compliance with the IECC performance path. Teams are also encouraged to use other simulation 

tools when appropriate for specialized building simulation analysis, provided the tool has met the 

requirements of BESTESTT

 

20 in accordance with the software certification sections of the 

RESNET/HERS Guidelines.21

Building energy simulations are often used for trial-and-error evaluation of “what-if” options in 

building design (i.e., a limited search for an optimal solution). In some cases, a more extensive 

set of options is evaluated and a more methodical approach is used. For example, in the Pacific 

Gas and Electric ACT2 project,22 energy-efficiency measures were evaluated using DOE2 

simulations in a sequential-analysis method that explicitly accounted for interactions. With 

today’s computer power, the bottleneck is no longer simulation run time, but rather the human 

time to handle input/output. Computerized option analysis has the potential to automate the 

input/output, evaluate many options, and perform enough simulations to explicitly account for 

the effects of interactions among combinations of options. However, the number of simulations 

still needs to be kept reasonable, by using an efficient search technique rather than attempting 

exhaustive enumeration of all combinations of options. Even with simulations that run in a few 

seconds, run time for an exhaustive study of all possible combinations is prohibitive for the 

millions of combinations that can result from options in the ten or more categories needed to 

accurately describe a residential building. Several computer programs to automate building 

energy optimization have been recently developed. For example, EnergyGauge-Pro23 uses 

successive, incremental optimization (similar to the ACT2 approach) with calculations based on 

the “energy code multiplier method” for Florida. GenOpt24 is a generic optimization program 

19 This is available for purchase from the Florida Solar Energy Center (http://energygauge.com/). 20 Judkoff, R., Neymark, J. 1995. International Energy Agency Building Energy Simulation Test (BESTEST) and 

Diagnostic Method. 300 pp.; NREL Report No. TP-472-6231. See further information at this Web site: 

www.eere.energy.gov/buildings/tools_directory/software.cfm/ID=85/pagename=alpha_list. 21 Residential Energy Services Network (RESNET). 2002. “Mortgage Industry National Home Energy Rating 

Systems Accreditation Standards.” Chapter 3, pp. 29-54. San Diego, CA: RESNET. 

22 Davis Energy Group. ACT2 Stanford Ranch Site, Final Design Report. Davis, CA: Davis 

Energy Group. 

23 Florida Solar Energy Center. EnergyGauge Pro. Cocoa, FL: Florida Solar Energy Center 

(http://energygauge.com/FlaRes/features/pro.htm). 24 Wetter, M. “GenOpt®, "Generic Optimization Program,” Seventh International IBPSA 

Conference, Rio de Janeiro, Brazil. (www.ibpsa.org/bs_01.htm). 

16 
for use with various building energy simulation programs and user-selectable optimization 

methods. 

To evaluate the cost required to reach a specific energy target, energy and cost results can be 

plotted in terms of annual costs (the sum of utility bills and mortgage payments for energy 

options) versus percent energy savings (Figure 6). The optimal least-cost path can then be 

determined by connecting the points for building designs that achieve various levels of energy 

savings at minimal cost (i.e., that establish the lower bound of results from all possible building 

designs). Alternatively, net present value or other economic figures of merit could be chosen. 

Inclusion of even a modest number of possible options for major system choices can lead to a 

very large number of possible building designs. One of the key challenges in developing a 

practical analysis method is to develop an approach that quickly focuses on the combinations that 

are nearest to the least-cost limit. To address these challenges, NREL is currently developing the 

BEopt Analysis Method. 

Points of particular interest on the least-cost path are shown in Figure 6 and can be described as 

follows: from the Benchmark at point 1, energy use is reduced by employing building efficiency 

options (e.g., improvements in space-conditioning systems, hot water systems, lighting systems, 

thermal distribution systems, etc.) A minimum annual cost optimum occurs at point 2. 

Additional building efficiency options are employed until the marginal cost of saving energy for 

these options equals the cost of producing power onsite at point 3. In this study, residential PV 

systems are used as the system option for onsite power. As research on distributed energy 

systems continues, it is anticipated that other onsite power technologies will also become 

available for residential-scale projects. From point 3 on, the building design does not change and 

energy savings are solely a result of adding additional onsite power capacity, until ZNE is 

achieved at point 4. 

The horizontal dashed line in Figure 6 defines solutions that provide energy savings at an annual 

cost that is less than or equal to the utility cost for the reference house when energy 

improvements are financed as part of a 30-year mortgage. All solutions in a vertical region below 

Figure 6. Least-cost curve calculated using the BE-opt analysis method 

17 
the neutral-cost line are essentially equivalent from an energy-savings perspective. The specific 

design package chosen by a builder to achieve a specific energy-savings level will depend on a 

number of factors, including material and equipment cost and availability, and overall 

homeowner preferences. 

Performance Verification 

Modeling provides the generalized energy calculations necessary to compare a prototype house 

to the Benchmark. Because weather, occupant behavior, and miscellaneous electric loads can 

dramatically affect actual energy use, it is essential that simulations be used to separate the 

objective performance of a prototype house from the effects of these uncontrolled variables. 

Modeling also allows the evaluation of “what-if” scenarios, where alternative design features are 

compared to those of the as-built prototype house. 

However, short-term field evaluations of actual prototype building systems provide information 

that modeling alone cannot. Field testing increases confidence in building models by improving 

simulation accuracy in areas that are difficult to know without direct measurements, such as duct 

and envelope air leakage, solar collector efficiency for solar hot water (SHW), and even the 

whole-building heat loss coefficient (UA). Common measurement techniques include tracer-gas 

tests, blower-door and duct-blaster tests, infrared imaging, current-voltage traces for photovoltaic 

systems (PV), and co-heating tests. Other tests are often developed based on the specific design 

features and uncertain performance characteristics of the house. 

The intent of short-term testing is to characterize the performance of unoccupied building and 

systems under controlled conditions, not under the idiosyncratic control of random occupants. 

Short-term tests may be repeated seasonally to characterize performance changes from winter to 

summer. These tests can also help identify equipment installation issues, operational problems, 

or malfunctions at an early stage before the occupants are inconvenienced. 

HERS raters are a valuable resource for continuing the process of energy-efficient construction 

with builders. Many Building America teams have successfully partnered with local HERS raters 

to provide initial testing, construction monitoring, and performance-verification testing services 

during the construction of test homes. The relationship between the builder and rater may 

continue after the test home, with the rater providing services, including ongoing performance 

verification and, in some cases, design and engineering services, depending on the rater’s skill 

set. 

The current RESNET HERS scoring system, which has been undergoing substantial change over 

the past few years, is of questionable value to builders participating in the Building America 

program, because they are generally most interested in whether they meet the overall energy 

efficiency goals of the program and not necessarily just achieving a score. It is not clear in the 

long run how builders will embrace and promote numeric scores provided by a system where the 

basis of the scoring system is periodically adjusted to reflect changes in codes or adding other 

energy end uses that make up the score. In this respect, a prescriptive set of criteria may be more 

valuable to builders – criteria such as those being developed by the Building America Program 

and the 2006 version of the EPA ENERGY STAR Homes® program with certain performance 

criteria pertaining to building and space-conditioning distribution system tightness targets. 

Whole-house energy-performance analysis may be the best approach for the industry instead of a 

18 
scoring system that periodically changes; is not comprehensive of all energy uses, which can 

cause confusion with homeowners; and is not easily marketed by the builder. 

Long-term field measurements provide valuable insights into the actual performance of the home 

under realistic conditions, including interactions between occupants and technology. Ultimately, 

it is essential for Building America to demonstrate that houses can meet the target levels of 

energy efficiency in reality and not just on paper. However, individual long-term tests under 

occupied conditions must always be put in the context of the specific occupants. Number of 

occupants, thermostat settings, operation of windows and interior shades, hot water and 

appliance-use patterns, and lifestyle are all important drivers of energy consumption. The 

recommended approach is, therefore, to compare measurements with simulated energy use based 

on actual occupant behavior and weather conditions and to make adjustments to the simulation 

based on the results of this comparison if justified. An adjusted energy savings analysis can then 

be performed based on actual instead of theoretical operating conditions. 

Long-term monitoring activities are still ongoing for the houses designed to meet the 30% 

savings target discussed in this report. The results will be reported in future technical 

publications, and the lessons learned will be used to inform future projects at the same or higher 

energy-savings target. Building America is committed to long-term energy savings, health and 

comfort, durability, and reliability of its system design recommendations at each performance 

level, and we will continue to track the performance of our prototype houses for several years to 

come. 

System Design and Construction Process 

Climate Analysis 

Key Climate Elements that Affect Building Design 

Houses should be designed and constructed in a manner that is suited to their environment, both 

exterior and interior. Rain, temperature, humidity, sunlight, and wind are examples of 

environmental loads that act on houses. 

The recommendations in this research report are applicable to houses constructed in the Cold 

Climate region. A Cold Climate (Figure 4) is defined as a region with approximately 5,400 

heating degree days (65°F basis) (3,000 heating degree days @ 18°C basis) or greater and less 

than approximately 9,000 heating degree days (65°F basis) (5,000 heating degree days @ 18°C 

basis). 

Individual locations within the broad general regions and zones described above can vary 

significantly. For a specific location, designers and builders should consider local weather 

records, local experience, and the microclimate around a building. Elevation, incident solar 

radiation, wind, nearby water and wetlands, vegetation, and undergrowth can all affect the 

microclimate. 

19 
Design Strategy Modification for Variances within a Climate Zone 

In general, the approach to rain control (Figure 7) is far more dependent on individual location 

within this climate zone, than the approach to energy efficiency. For example, levels of thermal 

insulation do not vary significantly across this region; however, approaches to rain control do. 

Figure 7. Rain exposure zones. Rainfall throughout the Cold Climate 

region varies dramatically from a low rain exposure zone to an extreme 

rain exposure zone. 

20 
Figure 8. Subdivision site plan for solar orientation25

Site Development 

Orientation Impacts 

To achieve the 30% level of energy savings, it is not necessary to orient homes in any particular 

direction. In many instances, the builder does not have any influence over lot orientation, and the 

house will face the street as laid out by the developer. The predominant window placement will 

typically be to the street and the back of the house. If it is possible to consider orientation at the 

site development level of the homebuilding process, one virtually no-cost option for improving 

energy performance is to subdivide for solar orientation. Alternately, on larger lots that do not 

have to “respect the street,” site planning can be undertaken to optimize the orientation of the 

house for passive solar benefit. An example of land planning and lot layout to allow for passive 

solar orientation is shown in Figure 8.

 

25 Shelley Dean and Fuller, Energy Principles in Architectural Design Architects California Energy Commission 

1981. 

21 
Landscaping 

While not a required strategy for achieving 30% whole-house savings, evaluating the vegetation 

on a lot and retaining trees that provide beneficial shading can be a low- or no-cost way to 

improve energy performance, predominantly by providing shade in the cooling season and 

helping to buffer or direct beneficial prevailing winds. Shade trees block summer sunlight before 

it strikes windows, walls, and roofs, dissipating absorbed heat to the air where it can be carried 

away by the breeze. It is most effective when located next to windows, walls, and air 

conditioners and when located on the side of the home receiving the most solar exposure in 

summer. Shade to the southwest and west is especially important for blocking peak solar gain in 

the summer in late afternoon. Trees more than 35 feet from the structure are probably too far 

away for shade. Trees to the north of a house in a Cold Climate can help block cold north winds, 

reducing one driving force for air infiltration. Trees, shrubs, and vines not only blocks sunlight, 

but also can cool the nearby air beneath the canopy or behind the plant by as much as 15°F 

because of natural evaporation from the plant's leaves. 

Water Management 

In natural settings, most precipitation infiltrates into the ground while a small portion runs off on 

the surface and into receiving waters. This surface runoff water is classified as storm-water runoff. As areas are constructed and urbanized, surface permeability is reduced, resulting in 

increased storm-water run-off volumes that are transported via urban infrastructure (e.g., gutters, 

pipes, and sewers) to receiving waters. These storm-water volumes contain sediment and other 

contaminants that have negative impact on water quality, navigation, and recreation. 

Furthermore, conveyance and treatment of storm-water volumes require significant municipal 

infrastructure and maintenance. 

Reduction and treatment of run-off volumes decrease or eliminate contaminants that pollute 

receiving water bodies. Minimizing the need for storm-water infrastructure also reduces 

construction impacts and the overall ecological footprint of the building. Finally, infiltration of 

storm water on site can recharge local aquifers, mimicking the natural water cycle. 

Strategies. Storm-water management strategies that prevent or reduce the pollution of water 

include the following: 

• Reduce impervious surface: The most effective method to minimize storm-water run-off 

volume is to reduce the amount of impervious area. By reducing impervious area, stormwater infrastructure can be minimized or deleted from the project. To minimize the 

impervious surface and to encourage the natural process of evaporation and infiltration, 

consider such methods as designing a smaller building footprint; clustering or concentrating 

developments to reduce the amount of paved surfaces, such as roads, parking lots, and 

sidewalks; and paving with pervious materials, such as poured asphalt or concrete with 

incorporated air spaces or concrete unit paving systems with large voids that allow grass or 

other vegetation to grow between the voids. 

• Storm-water harvesting: This method captures storm water from impervious areas to reuse 

within the building. Storm-water harvesting from roofs and hardscapes can be used for nonpotable uses such as sewage conveyance, fire suppression, and industrial applications. 

22 
• For storm-water volumes that must be conveyed from the site to a receiving water body, 

design treatment practices to match the needs of the location and the specific drainage area. 

Design storm-water facilities to remove contaminants and release the volumes to local water 

bodies. Utilize biologically based and innovative storm-water management features for 

pollutant load reduction, such as constructed wetlands, storm-water filtering systems, 

bioswales, bioretention basins, and vegetated filter strips. 

• Use vegetated buffers around parking lots to remove runoff pollutants, such as oil and grit. 

• Specify and install water-quality structures for pretreatment of runoff from surface parking 

areas. Do not disturb existing wetlands or riparian buffers when constructing ponds at the 

lowest elevations of a site. 

• Design storm-water runoff to flow into vegetated swales rather than into structured pipes for 

conveyance to water-quality ponds. Swales provide filtration for storm-water volumes and 

require less maintenance than constructed storm-water features. 

System Design Approach 

Integrated Design Process 

Typically a house goes through the following design process: 

• Conceptual Design Development. Planning Stage where the price range, square footage, 

number of stories, lot sizes, general features, and styles are determined. 

• Preliminary Design Development. Develop floor plan sketches, number of bedrooms, 

major options, basic circulation and function locations, as well as some elevation concepts. 

• Design Development. Preliminary structural, mechanical, electrical, plumbing, and 

Compliance. 

• Construction Documents Development. Final working drawings ready for bidding, 

submittal. Back-checking and coordination by consultants. 

• Construction and Commissioning. 

An Integrated Design Process (IDP) ensures that all the key players and design consultants - 

including the architect, planner, mechanical engineer, landscape architect, energy consultant, and 

the site engineer, work together starting with the conceptual design stage, even though the role 

of each may be limited for a particular design stage. The IDP is a key aspect in achieving the 

systems-design approach. 

An IDP approach may seem to be an expensive approach, but in the long run the overall costs 

and advantages significantly outweigh the traditional approach. For example, the mechanical 

engineer may be involved in the project much later and be asked to design the mechanical system 

with the already defined constraints of attic/plenum space–resulting in an inefficient HVAC 

distribution system. 

By developing a better IDP, builders are able to incorporate the 30% improvement level 

strategies more effectively with less disruption of their normal construction process and do so 

more cost effectively. While use of an IDP at the 30% improvement level for builders is quite 

23 
desirable, it will be even more important at higher energy-performance levels, 40%, 50%, and 

70% reduction. 

Approaches to an IDP will vary with different builders, as their relationships with design 

professionals, suppliers, and the trades are often different. For example, a builder with an inhouse architectural staff, that prepares all new house designs, may have a different level of 

control and continuity of design as compared to a builder that works with an independent 

architectural firm. Approaches to the IDP are evolving in Building America’s programs, and a 

single, clearly defined process has not been established. 

An example of this is the HVAC system because HVAC designers need to provide input as early 

as possible. They need to tell the architect which architectural features cause comfort issues and 

are difficult or impossible to overcome with typical HVAC practices. They also need to make 

sure the architect allows adequate space to run ducts. Many architects have had to re-design 

plans enough times as a result of HVAC issues that they know fairly well how to accommodate 

HVAC items. Still many problems commonly arise that could be avoided through earlier input 

and better coordination. 

To continue with our example, Table 5 shows the main trades and consultants who are affected 

by the HVAC system. The first column lists the item or issue and each subsequent column how 

each trade is affected by it. 

As shown from the matrix, all trades are intertwined in the design and building process. This 

matrix could be easily applied to the builder, electrician, plumber, etc. As homes become more 

efficient, it will be critical that all involved in the system will need to coordinate their efforts to 

ensure quality control and to employ quality assurance tools and processes through the IDP. 

One model of the information flows and actions associated with an integrated design process are 

shown in Figure 9. Some of the key activities of the integrated design process is setting a 

performance standard, identifying and integrating all systems in the house from the predesign 

stage through construction documentation, and having feedback loops in the design process from 

key participants in organization and trade base. 

Setting Performance Standards. In order to implement an IDP process, the team needs to have 

a set of standards to which the building will be expected to achieve. The first step in setting a 

performance standard is to understand the customer base and what level of performance they are 

receptive to. Targeted customer and market-area surveys help to give as clear a picture as 

possible of the factors that motivate home sales in general and home-purchasing patterns for the 

target market. This data is used to direct the design of new products and respond to market 

pressures. The ability to survey, synthesize, and extract meaning from customers and the market 

can provide a significant advantage to builders, in that they have a better understanding of 

market and can apply this knowledge to fulfill unmet needs. If the market is indicating a need for 

greater energy efficiency, durability, improved indoor air quality, or comfort, then the adoption 

of Building America performance packages may be appropriate as the standard. 

Similarly, the builder must determine what level of quality and performance their housing will 

achieve. This may have to do with moisture performance, comfort, increased durability, and 

reduced risk. All of these issues are typically addressed by following the recommendations 

included in this report. 

24 
Table 5. Matrix of Trades 

25 
ARCHITECTURE FLOW PURCHASING FLOW

Architecture begins

schematic design

CONSTRUCTION FLOW CONSU

Design is tested -

focus group or

internally

Yes

MARKETING FLOW

Consumer Focus Group

on Designs at closeout

of product Line

Develop program for

house - size, square

footage, style

Architecture creates

construction program

- structure,

mechanicals, etc.

Design is evaluated

for constructability

Design is reviewed

for cost

Design is evaluated

relative to program

Design

Approved

NO

Architecture 

design deve

Schematic HVAC

with all HVAC

vendors

10% CD Set

Architecture finalizes

schematic design

Diagrammatic

Structural

Spatial layout and

massing

Preliminary Energy

evaluation

Design is tested -

focus group or

internally

Design is evaluated Yes

for constructability

Design is reviewed

for cost

Design is evaluated

relative to program

Design

Approved HVAC layout Architecture begins Construction Documentation

Architecture finalizesDesign Development

Refine Structural

determine exact

dimensions,

materials, and code

compliance

Energy evaluation

NO

Final Energy

Modeling, Structural

& Duct Integration

50% CD Set

Final HVAC Design

R

Product Design

Process

Marketing determines

need for new or refined

product

MKTG / ARCH FLOW

Vendor Evaluation

and Feedback

Vendor Evaluation

and Feedback

Figure 9.26 Model of the information flows and actions associated with an integrated design proce

26 

26 IBACOS, Inc. KAAX-3-33410-06 B.2, Community-Scale Process Research Results. Pittsburgh: IBACOS. November 2004 
Set Goals Early in the Design Stage. By creating specific high-performance goals early in the 

design process, the design and construction team and their external vendors all have a clear 

understanding of the intent and performance metrics associated with a product line. As designs 

are being developed, all systems and strategies are considered, and feedback is solicited. This 

allows for early identification of potential conflicts or opportunities for alternate solutions before 

designs are finalized. 

The goal setting also demonstrates to vendors that the builder has committed to a level of 

performance, and all parties will need to play their role in seeing that it is achieved. A 

recognized best practice found by many of the Building America teams is a commitment to 

vendors to participate in long-term relationships, as opposed to simply forming relationships 

based on the lowest bid. This allows for mutual trust and respect to be built, and the opportunity 

to improve and innovate is increased. 

Gain Team-Based Feedback during Design. When asked about the most important design 

issue in its success in achieving higher performance levels, one participating builder identified 

framing as the area that they spend the most time on. The location of every stud, floor truss, and 

roof truss must be specifically located and coordinated with all other trades in order to make 

installation of other systems go smoothly and efficiently. This has been true throughout the 

Building America program. Builders may want to consider use of advanced CAD and 

panelization programs for generating a specific set of architectural and framing plans for each 

house type. It is important to work with the framing and HVAC contractors to identify conflicts 

and develop solutions before houses go into production. 

This process is continually being refined, and a best practice by some builders is to create a 

single system design that would be approved, installed, and warranted by any installing 

contractor. This can apply for many systems in the house including, but not limited to, framing, 

electrical, plumbing, and HVAC. For example this level of up-front design with the HVAC 

system helps control consistency and allows for better performance through proper sizing and 

design. It is important to have proper load calculations, equipment selection, and duct layouts 

with documentation that is somewhat transparent, so that HVAC vendors can evaluate system 

design options and agree upon a final solution. At this point, design changes can also be made to 

floor plan and framing layouts that can facilitate duct installation. While there is never a perfect 

solution for all parties, this level of discussion between the vendors, design, and construction 

greatly enhances the opportunity to “get it right.” This process can be applied for virtually any 

system in the house. 

Energy Analysis 

From purely an energy perspective, the section of this report on Analysis and Design 

Optimization describes the process involved with optimizing Building America houses. It must 

be noted that energy cannot be evaluated in a vacuum, and other issues have to be considered in 

the design process. In order for higher levels of efficiency to be accepted by builders and 

consumers, other key attributes of the house must be addressed. The systems-design approach is 

a process by which all the various subsystems in the house are evaluated and their 

interrelationships are understood, planned, and optimized. All of these systems must be designed 

and applied to realize both energy-related and non-energy-performance benefits associated with 

occupant health, safety, comfort, and long-term building durability and efficiency. To only 

27 
achieve energy efficiency without meeting these other criteria could cause consumer 

dissatisfaction and ultimately rejection of higher levels of energy efficiency, because the 

occupant’s other expectations of a new house are not being met. 

In a general sense, Building America houses include increased levels of thermal insulation, 

higher performance windows, significant air sealing, a strategy that eliminates the possibility of 

introducing the by-products of combustion into the house, a mechanical ventilation system, a 

properly sized and engineered space-conditioning system, higher efficiency space-conditioning 

and water-heating appliances, and may also include improvements in the efficiency of the 

appliances and lighting. The extent to which any of these strategies must be implemented varies 

by climate zone and the level of energy performance the builder seeks to achieve. A systemsdesign approach helps to assure that the energy-related aspects of the project are being satisfied 

in conjunction with the non-energy benefits and done so in a way that optimizes the synergies of 

the various systems in the house. 

Analysis results have shown that the most practical energy reductions to achieve at least 30% 

whole-house energy savings are in the end-use categories of space heating, space cooling, and 

domestic hot water. In general, energy reductions are not necessary in the other categories as 

long as energy savings averaging more than 50% are achieved in each of these three categories. 

As an alternative, a house design could include energy reductions in lighting or appliances to 

offset efficiency improvements of mechanical equipment. Energy reductions resulting from the 

use of solar thermal and photovoltaic systems are not necessary to achieve 30% savings. 

Passive Design Strategies for Minimizing Cooling and Optimizing Heating 

To achieve a 30% whole-house energy savings, it is not necessary to undertake any specific 

passive solar-design strategies. It should be recognized that proper orientation of the building and 

implementation of passive solar strategies can be a low- or no-cost method to significantly 

improve the energy performance of a house (see Appendix A for addition details on passive 

design). 

An almost invisible way of incorporating a “passive” strategy that is beneficial in all climate 

zones is the use of low-Solar Heat Gain Coefficient (SHGC) glazing in all fenestration units. 

This product generally has little impact on the visual characteristics of the window, and 

incorporating it does not require aesthetic redesign of the house. The 2004 Supplement to the 

2003 International Residential Code27 requires a SHGC of 0.4 in the Hot-Dry, Mixed-Dry, 

Marine, Hot-Humid, and southern parts of the Mixed-Humid Climate zones. Relatively low 

(0.30) SHGC glazing has been used successfully in 30% improvement homes in all climate 

zones. While a low-SHGC unit reduces beneficial heating season solar gain, Building America 

teams have found that where no attention is paid to passive solar design, low-SHGC windows 

generally provide a cost-effective option for builders, when all the systems interactions benefits 

are considered. The following are the reasons for this: 

• Traditional production-builder house models are oriented in any direction. Using lowerSHGC glazing in all windows assures an overall reduction of the heat gain during the cooling 

 

27 International Residential Code®: 2003 Edition with 2004 Supplement. Country Club Hills, IL: International Code 

Council, Inc. 2003, 2004. 

28 
season, regardless of how the house is placed with respect to the sun. This reduction in heat 

gain avoids some of the need for air conditioner operation, which is a net energy savings. 

• Air-conditioning equipment is sized based on peak load. Using lower-SHGC glazing reduces 

peak load and, in turn, reduces air-conditioning unit sizes. Smaller air-conditioning systems 

have lower airflows rates and, therefore, require smaller ducts. Lower airflow rates also 

require smaller fans, which use less electricity to operate. Reducing the size of the AC 

system also means cost savings to the builder, which can be reinvested in other energy 

upgrades. 

• The heating-season heat-gain penalty from the use of lower-SHGC glazing only occurs on 

cold sunny days. As seen in the map of Average Daily Solar Radiation for the Month of 

December (next page), there is comparably little solar resource across much of the northern 

United States in the winter months; thus, there is little opportunity for beneficial solar gain. 

In those areas of the Cold Climate zone where there is a good winter solar resource, highSHGC windows may be considered, but need to be carefully designed to avoid overheating 

south-facing rooms on sunny winter days and need to be properly shaded to reduce solar heat 

gain in the summer months 

• Use of low-SHGC glazing, by cutting the solar gain that varies in direction throughout the 

day, helps maintain more uniform room temperatures throughout the house. Even with 

zoned systems, it is not possible to control all room temperatures individually, and solar gain 

is one of the largest factors causing overheating and room-to-room imbalances. 

29 
Average south-facing vertical flat-plate radiation in December for the United States 

30 
Indoor Air Quality Strategies 

The Environmental Protection Agency ranks poor indoor air quality (IAQ) among the top five 

environmental risks to public health. Levels of air pollution inside the home can be 2 to 5 times 

higher (and occasionally 100 times higher) than outdoor levels. If too little outdoor air enters a 

home, pollutants can accumulate to levels that can pose health and comfort problems. Unless 

they are built with special mechanical means of ventilation, homes that are designed and 

constructed to minimize the amount of outdoor air entering the home may have a higher 

pollutant levels. 

Providing good IAQ at the 30% improvement level is important to maintain customer health and 

comfort and may minimize the possibility of high humidity levels and associated mold growth. 

Because 30% houses will have higher levels of insulation (which affects envelope hygrothermal 

characteristics) and will be reasonably air tight (which will affect internal moisture gain and 

removal), good IAQ requires a more proactive approach. Good IAQ requires control of indoor 

moisture, CO2, CO, NO2, SO2, ozone, particulates, dust mite dropping, odors, and other 

hazardous airborne contaminants. There are several approaches to good IAQ: (1) control the 

generating source, (2) remove the contaminant from the indoor air by ventilation or air filtration 

and/or, (3) physical cleaning (vacuuming, dusting, etc.) 

Source Control. Source control is the most positive approach in the 30% improved homes. A 

number of means of source control have been employed: 

• Control of moisture to remove one of the key support elements for mold growth. This is a 

broad subject and includes application of all of the following principles: 

o Proper flashing details for windows, doors, wall/roof junctions, penetrations of all sorts 

(pipes, ducts, skylights, etc.), attachments (such as porches and decks), offsets, and 

projections (such as bay windows) to control the entry of bulk water. 

o Control of envelope condensation potential through appropriate insulation and vapor 

permeability of layers. Appropriate designs must be applied for all components of the 

building envelope including walls, roof, and foundations. The section of this report on 

Cost Analysis discusses climate-specific assemblies. In addition, a builder may utilize 

other regionally specific guidelines such as the EEBA Builders Guides.28 At a more 

detailed level, static analysis techniques or dynamic models such as WUFI29 can be used. 

It should be noted that currently WUFI analysis will handle many wall and roof 

configurations, but it is not capable of foundation analysis. While ongoing research 

projects are adding to our knowledge of the hygrothermal performances of different 

forms of foundation insulation, following the practices outlined in the section on Cost 

Analysis should result in good moisture performance. 

o One wood-frame wall-construction detail that has proven quite effective for condensation 

control is to use an exterior insulating sheathing in addition to the traditional cavity 

 

28 Lstiburek, Joseph. 2004. Energy and Environmental Building Association. Builder’s Guide to Cold Climates: A 

Systems Approach to Designing and Building Homes that are Healthy, Comfortable, Durable, Energy Efficient and 

Environmentally Responsible. Westford, MA: Building Science Press. 

29 WUFI 2D, Version 2.1. Simulation of heat and moisture transfer. September 2000. 

31 
insulation. During the heating season, this helps to raise the temperature of the interior 

surface of the sheathing (the first condensing surface) above the indoor-air dew point. 

During periods of hot, humid weather, it acts as a vapor retarder and helps prevent moist 

outdoor air from entering the wall, which reduces the potential for condensation on the 

backside of the interior gypsum board in air-conditioned homes. For specific design 

considerations of this wall assembly, see further detail in the section of this report entitled 

Building Enclosure Integration Strategies, Walls Section. 

o Foundation waterproofing, damp-proofing, and capillary moisture control are important 

moisture management actions taken at the 30% improvement level. Failure to properly 

control moisture in crawl-space and full-basement constructions can result in high 

relative humidity in these spaces, which can lead to mold and mildew growth. 

Recommendations include the following: 

– Exterior foundation waterproofing/damp-proofing with a drainage layer and 

footing drain, to intercept and drain off exterior water. The drainage layer is often 

an impervious plastic mat, fiberglass or foam insulation board, or uniformly 

graded gravel. The insulation board offers the advantage of combining exterior 

foundation insulation (the most beneficial location for foundation insulation) with 

a good drainage material. 

– After a heavy rainfall or after water has been applied for irrigating grass or 

plantings near the house, moisture can accumulate below and next to a footing. 

Moisture movement, by capillary action, can occur from this location through to 

the concrete footing and, from there, the moisture can be transferred into the slab 

or concrete or block foundation wall. Water stains on the perimeter of the slab or 

at the interior of the foundation wall can result and are not only unsightly, but 

they also offer an environment for mold growth to occur. This moisture pathway 

may be controlled by forming a continuous capillary break between the ground 

and the concrete foundation system. With monolithic slab-on-grade construction, 

polyethylene sheeting should be placed under the entire slab and footing up to 

grade. With footings poured independent of slabs or with foundation walls, a 

bituminous damp-proofing coating, masonry capillary break paint, or a layer of 

poly can be used to isolate the footing form the remainder of the assembly. 

• Air leakage control is another key method of reducing IAQ pollution sources. Air leaking in 

from the outdoors may carry outdoor air pollutants (including vehicle exhaust and plant 

pollens) into the house, but outdoor air is typically (though not always) considered a fresh-air 

source. What outdoor air does bring, in hot humid weather, is moisture that can condense on 

internal building components that may then support mold growth. In winter, air leakage 

outward through the building envelope can bring relatively moist indoor air into contact with 

cold surfaces. Building envelope air sealing (in addition to reducing energy consumption) is 

valuable to reduce moist-air migration that could lead to mold growth under both summer or 

winter conditions and reduce occupant exposure to outdoor pollutants. 

• Sealing against air leakage is primarily for thermal reasons, but when coupled with 

appropriate mechanical ventilation it also assists in providing good IAQ for the occupants. 

Extensive air sealing is one of the primary 30% improvement strategies. It includes a range 

of recommendations to builders including the following: 

32 
o Developing a continuous air barrier with interior gypsum board on walls and ceilings 

giving attention to sealing at edges and joints, around penetrations and electrical boxes 

(including ceiling recessed downlights). Particularly important is to get sheathing 

continuity behind bathtubs and showers, at fireplaces, soffits, stairways, and at the band 

joist. 

o Developing an air barrier with exterior sheathing using taped and caulked joints. 

o Foam sealing (non-expansive) around window and doorframes. 

o Construction of well-sealed attic access hatches. 

o Taking particular care to seal all contact surfaces between attached garages and the 

occupied house. This must include sealing at all penetrations and the provision of 

gasketed, self-closing doors between garage and house. 

• Seal forced-air distribution systems. Leaky duct systems contribute to poor IAQ in several 

ways. Leaky ducts can cause pressure imbalances, which can draw air from the outdoors, 

building cavities, or attached garage spaces. In addition, pressure imbalances can move 

moisture-laden air into building cavities where the water vapor can condense, causing a 

habitat for mold and mildew. Specific strategies and techniques associated with the proper 

design and construction of air distribution systems can be found elsewhere in this report. 

• Control of radon and other soil gasses. The principal method of controlling the entry of 

these gases into a house is through the use of under-slab ventilation. House pressurization 

can be effective for this purpose as well, but is difficult to implement and control with 

current HVAC technologies. Under-slab ventilation typically takes the form of modest depth 

of uniformly graded crushed stone (i.e., with good void spaces) 4 in. to 8 in. deep in which is 

embedded an array of perforated-plastic drainpipe and covered with a poly air/vapor barrier. 

The piping is linked by a header to which is connected a vertical vent pipe leading up 

through the house and out at the roof. This system is often installed as a precaution even 

when no evidence of radon has been shown because it is far easier to do this than to come 

back later and retrofit an under-slab venting system. Usually the vent goes through the roof 

and functions as a passive vent. It is designed, however, for the subsequent installation of an 

exhaust fan should the need for a more positive ventilating action be demonstrated. An 

electrical outlet for a possible future fan installation is located in the attic or basement 

adjacent to the vent pipe. Further information on sub-slab ventilation systems can be found 

in the EPA’s Model Standards And Techniques For Control of Radon in New Residential 

Buildings30

• Combustion Safety. To avoid the possibility of the introduction of the by-products of 

combustion being brought into the house, several components associated with combustion 

safety must be addressed in the 30% improved house. Because these houses are generally 

quite air tight, natural draft appliances are not recommended. The basic recommendations 

are as follows: 

o Furnaces. Use sealed-combustion units or draft-induced units with dedicated make-up 

air so that the combustion process is atmospherically decoupled from the house itself. 

 

30 Environmental Protection Agency. Model Standards and Techniques for Control of Radon in New Residential 

Buildings. Environmental Protection Agency Website. www.epa.gov/radon/pubs/newconst.html

33 
o Tank or tankless domestic hot water heaters. Use sealed-combustion, direct-vent, or 

power-vented types that are atmospherically decoupled from the house. 

o Fireplaces. If fireplaces are installed (gas-fired or solid-fuel-burning), use units that 

directly vent the by-products of combustion to the outdoors, are equipped with tightfitting glass doors, and preferably use outside air for combustion. 

o Gas Appliances. Eliminate unvented gas appliances except cooking appliance, which 

should be vented to the outdoors by a ducted range hood. 

• Finishes. Finishes such as paints, sealers, adhesives, fabrics, and surface-covering roll goods 

(e.g., vinyl wall coverings) are all potential sources of indoor air pollutants, including various 

volatile organic compounds (VOCs). Most of the liquid-applied materials dissipate rather 

rapidly as they dry; leaving windows open as they are applied and dry removes the high 

initial concentrations. After this initial “dry out” period, a properly designed ventilation 

system will continue to bring in fresh air and remove further off gassing of pollutants. Thus, 

for any but highly sensitive occupants, the selection of special, low-VOC, materials and 

finishes is not seen as necessary to achieve the 30% whole-house energy-savings level. 

Should a homeowner have IAQ sensitivity needs, then the application of the American Lung 

Association (ALA) Health House Specifications31 or specifications to meet the EPA’s Indoor 

Air Quality (IAQ) Label32 would be appropriate. 

• Relative Humidity Control. The control of indoor relative humidity (RH) is another key 

strategy to maintain good IAQ. The desirable range of indoor RH is from 20% in winter to 

65% in summer, with a preferable range of 30% to 50%. Ventilation strategies play a key 

role in maintaining these ranges and are discussed more fully in the ventilation section of this 

report. However, a variety of ventilation forms including heat recovery ventilators (HRVs) 

or energy recovery ventilation (ERVs) are used to remove excess humidity in the winter and 

ERVs, dehumidifying ventilators, dedicated dehumidifiers, and advanced HVAC control 

systems are used to control excess humidity in the summer. The importance of winter or 

summer humidity control, of course, varies with climate region. 

• Pollutant Removal and/or Dilution. Ventilation and air cleaning are the principle methods 

of airborne pollutant removal or dilution. Ventilation system design and strategies are treated 

more fully in the section of this report on Building America System Research Results, but 

key features relative to good IAQ in 30% improvement houses will be noted here. 

o Whole-house mechanical ventilation in accordance with ASHRAE Standard 62.233 is 

recommended. Any of a number of system configurations can meet this requirement and 

include the following: 

– Passive inlet direct to the return air duct with appropriate dampers and controls 

– Dedicated supply fans designed for continuous operation 

– HRVs or ERVs 

 

31 American Lung Association. Builder Guidelines. American Lung Association® (ALA) Health House®. 

www.healthhouse.org/build/Guidelines.asp October 1, 2004. 

32 Environmental Protection Agency. Indoor Air Quality Label. Environmental Protection Agency Website. 

www.epa.gov/iaq/energystar/label_specifications.html. 2004. 33 ANSI/ASHRAE 62.2-2004, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings 

34 
– Dedicated central dehumidifier with ventilation. 

o Whole-house ventilation air should be distributed to all the primary occupied spaces in 

the house, particularly bedroom and living areas. This is typically accomplished by 

ducting ventilation air into the heating/cooling duct system. For this distribution to be 

continually effective, however, the HVAC system must be periodically cycled, even at 

times when no heating or cooling is required. Dedicated ventilation distribution ductwork 

is occasionally used, particularly if no forced-air systems exits, but it is a more costly 

option. Fresh-air intakes should be provided with nominal filtration to prevent the entry 

of insects and large particulates. 

o For good IAQ, the HVAC return-air stream should be filtered with a 4-in. standard filter 

or a new Minimum Efficiency Reporting Values (MERV)34 6 or 8 normal-thickness 

filters. Ventilation air should also pass through this filter, if possible. Filters should be 

easily accessible for cleaning or replacement, and the filter slot should be designed so 

that there is no air bypass around the filter when the HVAC system is operating. 

o It is important to provide local exhaust fans for bathrooms, range hoods in the kitchen, 

and exhaust fans in other areas where pollutants may be generated (utility, hobby rooms, 

etc.) All of these fans must be ducted to outdoors via the most direct path. 

o Ventilation technology has developed significantly in recent years, but a few areas 

remain problematic: 

– It is difficult to find low airflow ventilation units, particularly HRVs and ERVs. 

– Design of distribution systems is a challenge. Using HVAC ductwork requires 

cycling the central fan, which increases the electric consumption. Dedicated 

ventilation ductwork is quite small and must be well designed to function 

properly. The ventilation air from a dedicated ventilation fan (i.e., ERV, HRV) 

may not be fully distributed to all rooms when only the ventilation airflow is 

being moved through the larger ducts of the central space-conditioning system. 

– Builders do not like the additional cost of installing a ventilation system and often 

have a difficult time explaining to the consumer why it is needed. 

– Ventilation controls are often difficult to integrate with the HVAC system 

because the products are not usually designed for integration. A newer generation 

of integrated ventilation and space-conditioning controls are beginning to be 

introduced by major manufacturers, and it is anticipated that this trend will 

continue in the future with more options becoming available to builders. 

– Ventilation should be accomplished in the most energy-efficient manner, 

balancing fan energy consumption with the cost of conditioning the ventilation 

air. 

• Physical Cleaning. Builders have very little control over occupant behavior and, as such, 

there are limited strategies a builder can incorporate in this area. One primary opportunity is 

in the installation of a whole-house vacuum system that exhausts to the outdoor, which limits 

the reintroduction of dust in the house. Another is the inclusion of a discussion of 

 

34 See www.filters-for-home.com/merv.htm for MERV definitions. 

35 
maintaining good indoor air quality in an owners’ manual for the house, including cleaning 

practices as they relate to indoor air quality. 

Heating and Cooling Equipment and Distribution Strategies – Creating Conditioned 

Space for HVAC Systems 

For the 30% improvement house and all new home construction, it is highly recommended that 

the heating and cooling system be designed according to industry standard methodologies, most 

notably ACCA Manual J,35 S,36 D,37 and T.38 With the use of low-SHGC glass, it is practical to 

design each house model of a builder’s line for the worst orientation without significant penalty 

in other orientation. The use of low-SHGC glazing reduces the solar component of the cooling 

load and helps to level the cooling load and minimize variations resulting from orientation. 

Whenever practical, the design should be specific to an individual house and its orientation. 

System implications based on variations in orientation are the result of the different solar loads 

and, for system design purposes, do not affect heating loads. The impact is primarily on the 

cooling system design because of solar load through windows. 

Heating and Cooling Equipment. The preference is for a single heating/cooling unit to serve 

the entire house, frequently utilizing a zoning system with multiple fan speeds and variable 

output. This is an efficient approach and allows the closest tailoring of unit size to peak and part 

load conditions. In some cases, especially homes more than 2,500 ft , two or more units may be 

needed in order to meet the load or to serve distinct zones in the house. With the better thermal 

envelope of the 30% improved house, a single HVAC unit may often be feasible where two were 

used before. A single HVAC unit with zoning dampers and controls is also better able to adapt 

to major load differences. It is strongly recommended that the air-handler unit be located within 

the conditioned space of the house. When located in unconditioned space, as in vented attic or 

garage locations, the units are exposed to full winter and summer temperature conditions and 

experience major thermal losses, because HVAC units are poorly insulated and have significant 

air leakage. 

2

More detailed discussion of heating and cooling equipment selections are given in the section of 

this report on Space Conditioning and Ventilation. In the 30% improvement house, the 

recommendation is to use a sealed-combustion furnace or draft-induced unit with dedicated 

make-up air so that the combustion process is atmospherically decoupled from the house itself, 

located in conditioned space, for efficiency and combustion safety reasons. 

A high-efficiency electric heat pump may also be an effective choice for heating, although 

because of the source energy conversion a Heating Season Performance Factor (HSPF) of 

approximately 9.7 is necessary to match the source energy efficiency of a 92% AFUE furnace. 

Where the thermal envelope of the house has been significantly improved, the heating load may 

be dramatically reduced and the cost effectiveness of a gas furnace and all the associated piping 

 

35 ACCA. Manual J: Residential Load Calculation 8th Edition. Air Conditioning Contractors of America, Arlington, 

VA 2003. 

36 ACCA, Manual S: Residential Heating and Cooling Equipment Selection, Air Conditioning Contractors of 

America, Washington, D.C., 1995. 

37 ACCA, Manual D: Residential Duct Systems, Air Conditioning Contractors of America, Washington, D.C., 1995. 

38 ACCA, Manual T: Air Distribution Basics, Air Conditioning Contractors of America, Washington, D.C., 1993. 

36 
and utility infrastructure costs need to be weighed against the potential increase in source energy 

consumption associated with using a heat pump with a HSPF lower than 9.7. 

Air conditioners in Cold Climates should have SEER ratings of 13 or greater, which will be code 

minimum starting in 2006. It should also be noted that there is a wide range of cooling 

requirements in the Cold Climate zone, and SEER rating should be evaluated based on annual 

hours of operation. In general, the greater the cooling need, the higher the SEER rating should 

be. From a design standpoint, if the architecture of the home incorporates passive strategies for 

cooling-load reduction (such as shaded south, west, and east glass; minimized unshaded west 

glass; or a design that incorporates low-SHGC glazing and a small number of windows), cooling 

system run hours can be reduced and smaller-capacity equipment will be appropriate. In some 

parts of the Cold Climate zone, designers should also recognize that because of the minimal 

latent loads, some of the latent capacity in the equipment can be used for sensible load. In 

general, the sensible capacity equals the total capacity when the design wet-bulb temperature of 

the return air is less than 59°F. Designers need to check the mean coincident wet-bulb 

temperature at outdoor design conditions and select equipment based on this. This strategy helps 

to prevent oversizing of the equipment. 

Air Distribution Systems. To achieve a 30% whole-house energy reduction, a number of 

requirements apply to design of the duct system: 

• Design should be in accordance with ACCA Manual D 

• Ductwork should be located within the thermal envelope of the house or in some locations in 

the Cold Climate zone they may be buried in attic insulation 

• Ducts should not be located in exterior walls 

• Ducts must be air-sealed using UL 181-approved mastic or equivalent for the particular duct 

type 

• “Panning” between joists and the use of stud cavities for supply or return air is not 

recommended 

• Ducts may be of galvanized sheet metal, duct board, or flex duct 

• There must be continuity of the vapor barrier on insulated ducts not running inside 

conditioned spaces. 

Sometimes duct systems need to run in unconditioned spaces. For a discussion of the treatment 

of these ducts, see the section entitled Space Conditioning and Ventilation Systems. 

To accommodate heating and cooling units and duct systems within the thermal envelope of the 

house, a number of techniques may be employed. This typically impacts the architectural design 

of the house and should be considered at the early schematic phase of design. Keeping ducts 

inside the conditioned space may also involve framing systems that allow ducts to be run through 

it, such as an open-web floor-truss system. Alternately, dropped soffits, tray ceilings, and lower 

ceiling heights in “service” function rooms like baths, hallways, and closets can accommodate 

ducts inside the envelope. Strategies include the following: 

• Locate ducts within an insulated, non-vented, conditioned crawl space or basement 

• Locate ducts within an insulated “cathedralized” attic 

37 
• Locate ducts in open-web floor trusses 

• Develop chase walls to accommodate duct risers 

• Design closets inside the conditioned space for locating the air handler in houses using slab 

on grade construction. 

More specific discussion of many of these recommendations is found in the section of this report 

on Space Conditioning and Ventilation Systems. 

Where a boiler or water heater is used for space heating, a hydronic distribution system is 

necessary. These are particularly suited to Cold Climate applications where there may not be a 

need for air conditioning and the associated duct distribution system. Their most common 

configuration is a radiant floor or baseboard convection units. If a radiant floor system is selected 

in a slab-on-grade installation, it is required than the slab be insulated from the ground and at the 

slab edge with at least R-10 (2 in.) of rigid insulation. Slab edges need to be insulated because it 

is exposed to cold exterior conditions. If a boiler or water heater serves a fan coil and ducted 

system, all recommendations for ducts noted above apply. Hydronic systems are described in 

more detail in the section on Space Conditioning and Verification Systems. 

First Costs, Cost Tradeoffs, and Owner Annualized PITI + Energy 

Useful and representative costs information for 30% improvements has not been easy to 

determine. In many cases these are pilot homes and are the first of this level of energy 

performance that have been done by a builder. Thus, the energy-use-reduction construction 

strategies are new to the builder, and costs do not represent a mature purchasing structure or 

experienced installation practices. Furthermore, there are often compensating or beneficial 

attributes of the improvement strategies that are not realized until multiple houses are built. An 

example is the ease of air sealing that is inherent with spray-foam insulation systems that replace 

tedious hand caulk and foam-gun sealing done by laborers. Until a builder experiences the 

change, it is usually not valued. 

Some of the common cost tradeoffs that builders in the Building America program have used 

include the following: 

• Reduced costs associated with advanced framing 

• Reduced costs associated with downsizing space-conditioning equipment and simplifying 

air-distribution systems 

• Increased costs for higher performance windows and insulation and air-sealing packages, that 

enable the reduction in HVAC system size 

• Substituting insulating sheathing for structural panel sheathing increases wall insulation 

levels at low or no incremental cost 

• Increased cost of installing mechanical ventilation 

• More usable floor space in slab on grade construction through the use of tankless water 

heaters instead of tank type water 

38 
Builders who commit to evolving their organizations to the consistent production of quality highperformance homes face a transition period. Figure 10 illustrates how the organization will 

typically change through phases and the corresponding change in first costs. 

The transition strategy outlined here provides a logical progression to higher performance 

housing, but builders need to be prepared to make an investment in other costs associated with 

implementing a high-performance package, including staff and vendor training, product 

redesign, collateral development, and testing. Each of these issues will be discussed and 

suggestions made as to best practices in order to minimize costs. 

If the steps taken to transform a company are followed, a builder will have a transitional period 

where higher costs will be incurred. It is only at the last step, where integrated designs are 

developed, that a builder can realize immediate construction cost savings. If the total operational 

costs of running a homebuilding business are considered, potential cost savings should begin to 

accrue from the first step. Incremental Construction Costs 

Transformation Stage 

Indoor Air Quality 

Water Management 

Thermal Enclosure Improvement 

Tighten Ducts 

Integrated Design 

Full-scale implementation 

Figure 10. Incremental Cost versus Transformation Stage Curve 

39 
Water Management 

Because many warrantee issues are associated with water intrusion, a solid water management 

plan can reduce future costs, limiting the reserves builders need to put aside for future claims. 

Analysis of past history of water-damage issues, both short-term and long-term, can help 

quantify the per-house costs associated with the “status quo” versus an improved watermanagement strategy. 

The improvements to the Indoor Air Quality, Thermal Enclosure, and Duct Sealing will all 

require additional expense. It is, therefore, important to successfully integrate these strategies as 

quickly as possible. This is where relationships with vendors are critical. Builders must be 

willing to support the trades during the transition; however, trades must take some level of 

responsibility for adapting and developing cost-effective solutions for delivering improved 

performance. Examples of this include rethinking duct installations to allow for prefabrication 

and sealing of major components or panelization of structural systems to speed erection, cut 

cycle time, and reduce costs. In addition, vendors must have continuing education costs built into 

their overhead structure. 

A diagrammatic Incremental Construction Cost versus Transformation Stage curve on a per 

house basis for a builder might be as seen in Figure 10. It should be noted that this curve is 

diagrammatic by nature and will vary from builder to builder and by region. For example, if a 

builder has already addressed water management, then there is no expected incremental cost 

associated with this practice. Also note that the tail end of the curve still shows some increase in 

costs. This represents the most conservative scenario, where a builder has already optimized 

many aspects of their houses (i.e., integrated advanced framing or does not significantly oversize 

HVAC equipment). For the consumer this added cost is offset by reduction in utility bills and, as 

discussed in the section on System Approach to Least-Cost Energy Savings, should prove to be 

net cost neutral or even put the consumer at a net positive monthly cash flow. 

In order to achieve the goals of a high-performance home transformation, builders and vendors 

must embark on a training program that engages all levels of the companies. Training must be 

provided for different levels of employees within the company and for the different departments 

within the company. 

The integrated design process comes with some inherent additional costs, especially if the 

builder takes responsibility for HVAC system design, as opposed to having the vendors do a 

“design build” system. The advantages of the builder doing the design are that a greater level of 

consistency can be achieved and documentation exists for site supervisors to readily check work. 

It does involve additional costs, either through contracting with outside designers or by training 

and utilizing internal resources to cover systems integration, including HVAC, framing 

integration, and detailing. In addition, the cost of re-bidding work involves time and expense on 

the part of the builder’s purchasing department, the trades, and their suppliers. For this reason, it 

is best that as a builder transitions to a high-performance approach, they do it as part of their 

ongoing product redesign process, where many of these activities are already budgeted for. 

Unfortunately, this can lead to a disparity in the builder’s marketing approach because some 

product may meet the new standards and others may not during the transition period. Builders 

must evaluate the volume they are building, the number of plan types, the current redesign cycle, 

40 
41 

and the uniformity of marketing message they wish to project when doing this cost benefit 

analysis. 

During the transformation, builders will need to be measuring how well they are doing compared 

to the performance goals they set. This measuring requires undertaking some level of 

performance testing. Typically this performance testing will be 100% during the initial steps in 

order to gain insight into the effectiveness of various practices and techniques being used in the 

field. As vendors become adept at achieving performance targets, some builders have chosen to 

ramp down testing activities, while others have chosen to maintain 100% testing as a qualitycontrol measure. In either case, performance testing is a cost that needs to be budgeted for. 

Some cost data has been developed from recent Building America projects at the 30% 

improvement level. The extent of improvement work varies considerably depending on the 

thermal performance quality of a builder’s basic model. These costs are also generally not 

representative of mature costs and, in some instances, are reduced because materials have been 

donated by manufacturers. 

Table 6 is one example of the incremental costs associated with achieving 39% energy savings in 

a house in one community in Pittsburgh, Pennsylvania. The case study for this project, Kacin 

Homes, is included later in this report. 

It should be noted that this house included an extensive use of hard-wired fluorescent fixtures, 

which substantially increased the cost of the project. Similar lighting savings could have been 

achieved at significantly lower costs with screw-in replacement CFLs; however, this house was 

part of a more comprehensive research study on strategies for hard-wired energy-efficient 

lighting solutions. While the builder was already familiar with achieving well above ENERGY 

STAR Homes® levels of performance, the incremental costs for water heating reflect a “firsttime” incremental cost and should be reduced if the builder implemented this throughout all of 

their houses and negotiated volume pricing. 
Energy Features Energy Features Base Code IECC 2003 Building America Incremental Cost E

ENVELOPE: (Insulation U-Values or R-Values)

 Roof (attic) U-value = 0.030 38 (U-value = 0.025)

 Wall (Exterior) U-value = 0.060 R-15+1 inch XPS (U-value = 0.067) $400 Floor (above garage) U-value = 0.033 N/A

 Floor (cantilever) U-value = 0.033 N/ACrawl Space Wall U-value = 0.065 Low Air Infiltration No 3.8 ACH at 50 Pa $200

GLAZING:U-Factor

Wood-framed, double-glazed, argonfilled units 

Builder upgraded windostandard before this prono incremental costs

 Double Hung Uvalue =0.35 U=0.33,

SHGC

Double Hung SHGC = .55 SHGC = 0.31

HVAC SYSTEM:

 Furnace: AFUE 0.78 0.91 $500

 A/C: SEER 10 SEER 13 SEER $500

 Duct Insulation / Location 5.00 13.0 (buried in insulation) Duct Testing No Yes

 ACCA Manual D No YesVeetilation No Energy Recovery Ventilator $1,500

WATER HEATING:

 Water Heater Size 40 gal Tankless System $1,500

 Energy Factor 0.54 0.82

 Distribution Type Standard Standard External Wrap None None

Solar Credit None None

3rd Party Inspections and Testing 1 in 7 tested Paid for by Community 

Fluorescent lighting 

Extensive hard wired flourescent lighting package $8,000

Appliances NAECA Minimum Al Energy Star $800

Total Estimated upgrade cost $13,400Total Estimated cost excluding lightng $5,400

CASH FLOW Total Incremental Cost $13,400.00

Total Incremental Cost Excluding Lighting $5,400.00Estimated Monthly Energy $28Monthly Amortized Cost $36.26 At a 7% interest rate For 30 years 

Net Monthly additional cost

Table 6. Illustrative Incremental Costs of a High-Performance Home39

Energy Features Kacin Homes Specifications 

42 

$7.93

Energy Features IECC 2003 Code Compliant 

39 1815-ft2 home in Pittsburgh, Pennsylvania 
Reducing Construction Waste 

Research conducted by the National Association of Home Builders (NAHB) and the NAHB 

Research Center shows that 87.7% of the 1.7 million homes built in the United States in 1999 

were stick-framed, that a “typical” home consumes just over 13,100 board feet of framing 

lumber (about three-quarters of an acre of forest), and that the wood scrap pile for the 

construction of this “typical” home is approximately 2 tons. 

A combination of factors has worked to increase the consumption of wood in home building. 

Single-family detached units. A single-family detached home uses more wood per household 

than multi-family housing. According to NAHB, single-family detached units went from about 

71% of overall housing starts to nearly 80% just between 1978 and 2001. 

Home size. In the past 40 years, the median new home size in the United States has increased 

from 1,365 ft2 to well over 2,000 ft2, this despite the fact that household size has actually 

decreased by 20%. 

Complexity. Not many of today’s homes are simple in form. Jogs, dormers, vaulted ceilings, 

convoluted roof lines, and elaborate staircases are common in new homes. 

Safety standards. We require more of our structures today, particularly in regions with seismic 

and wind considerations. Re-engineering for these loads has resulted in some increase in wood 

use, but has also spawned site practices that simply “throw more wood” at the problem. 

Lumber versus labor. Just as the relative value of materials versus labor seems to have reversed 

(today, materials are “cheap”—it’s the labor that is “dear”), the typical skills set of both 

designers and framers has diminished, leading to waste at the front and tail ends of wood 

construction. 

The nature and structure of the industry. Home building is like no other production process in 

the 21st century. Nearly all of the 1.7 million homes built each year are site-built, making home 

building one of the most fragmented of industries in the United States. It is journeymen 

framers—not architects, engineers or even general contractors—who control what and how much 

wood goes where on the job site. And most training occurs informally, by word-of-mouth, during 

production. 

Two-foot Module Design 

Starting with foundation layout, the house footprint should be based on 2-ft increments, often 

with significant savings in framing members and sheathing and always with a lot less waste. 

Sheet goods come in 4-ft. by 8-ft. dimensions. Layouts should be based on the fundamental unit 

dimensions of the materials used. Work by the NAHB Research Center found that the wood 

savings are dependent on the starting dimension. 

Value-Engineered or “Advanced” Framing 

There are a number of substantial advantages to optimized framing: it saves time and money up 

front, it improves homebuyer satisfaction, its saves money and energy over the long term, and it 

improves builder image. 

 43 
More than 7,000 homes built by Building Science Consortium production builders have used 

advanced framing. The resultant savings in waste are the products of “systems-thinking” and a 

breakdown of age-old myths about how wood framing works. 

The following sections are descriptions of the major optimized framing techniques, with 

appropriate references from the International Residential Code,®40 cited in brackets. 

Frame 24 in. on center. The prevailing practice is to frame walls, floors, and often roofs at 16-

in. centers. However, 24-in. centers are structurally adequate for most residential applications. 

Even when the stud size must be increased from 2x4 to 2x6, changing spacing from 16 to 24 in. 

can reduce framing lumber needs significantly. See Figure 11 for an example. 

Align framing members and use a single top plate. Double top plates are used principally 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. For multistory homes that are framed 

with 2x4s, this may increase the stud size on lower floors to 2x6; however, there is still typically 

a net decrease in lumber used [Section R602.3.2 of the Code. A single top plate is listed as an 

acceptable option for in-line framing and with properly tied joints]. Figure 12 illustrates the 

alignment of framing and use of single top plates. 

Figure 11. Advanced framing layout showing 24-in. stud centering 

 

40 International Residential Code®. 2003 Edition. Country Club Hills, IL: International Code Council, Inc. 2003. 

 44 
Figure 12. Advanced framing showing truss alignment with 

stud framing and single top plates 

Size headers for actual loading conditions. Headers are often oversized for the structural work 

that they do. Doubled-up 2x6 (or 4x6) headers end up in non-load-bearing walls. Doubled-up 

2x12 (or 4x12) headers end up in all load-bearing walls, regardless of specific loading 

conditions. “Load-tuned” headers should be in the vocabulary and practice of all engineers, 

architects, builders, and framers [Section R602.7.2. This section states that non-bearing walls do 

not need structural headers]. 

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 is called “ladder 

blocking” or “ladder framing.” This also creates room for more insulation. Figure 13 shows a 

ladder block configuration. 

Use two-stud instead of three-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 nailer strip or a recycled plastic nailing strip can be used 

 45 
instead. Using drywall clips also reduces opportunities for drywall cracking and nail popping, 

frequent causes of builder callbacks. Figure 14 shows various stud corner arrangements.

Eliminate redundant floor joists. Double floor joists are often installed unnecessarily below 

non-load-bearing partitions. Nailing directly to the sub-floor 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 

in. on-center or 2x4 “flat studs” at 16 in. on-center [Section R602.5]. 

Figure 13. Example of ladder block exterior wall intersections 

Figure 14. Wall stud corner configurations 

 46 
Compact Duct Systems 

A framing plan can do more than just lay out floor joists. There are opportunities to valueengineer the floor system and obtain a proper joist count, to ensure that all plumbing is 

coordinated with the floor framing, to ensure that all HVAC is coordinated with the floor 

framing, and to ensure that the “stack framing” concept is followed on the job site. Most 

importantly, all these issues are resolved on paper before casting the foundation. Figure 15 and 

Figure 16 show compact duct system layouts. 

Figure 15. Three-dimensional example of compact duct system41

 

41 Heating and cooling equipment shown in green, return duct shown in blue and supply ducts shown in brown. 

 47 
Figure 16. Example of a compact duct layout 

Recycling of Construction Materials 

No matter how efficient our use of wood, there will be some waste—cut-offs from both solidsawn lumber and sheathing. Even for the most efficiently framed buildings, wood waste will be 

one of the largest components of the new construction waste stream. 

Reduced wood purchase and disposal costs. Actual field counts for a production builder in 

California have found a 40% reduction in the cost of a wall-framing package after implementing 

optimized framing methods; a purchase savings for the builder of more than $1,100 on each 

house. Another builder in Maryland reduces total wood waste disposal by 15% using efficient 

framing. Neither of these examples takes into account the labor savings from handling less wood 

and wood waste. 

Reduced environmental impact. The annual toll for residential construction in the United 

States is 2 billion board feet of framing lumber and nearly 2.5 million tons of wood waste. That 

 48 
translates into 1.1 million acres of clear-cut forest and 30-yard dumpsters lined up end-to-end 

from Phoenix to Chicago! Clearly, builders can achieve and claim significantly reduced global 

and local environmental impact with optimized framing. 

On-site grinding. Waste that is grinded into wood chips makes a great soil-erosion-control mat 

at job site entrances or bermed at the base of silt fences. 

Quality Project Management Approach 

A key component of high-performance system design and any high-performance construction 

process is quality project management. Quality management is a well-traveled term, but its 

definition can be elusive. In terms of Building America high-performance homes, the following 

definition is useful: 

Quality management is an ongoing effort to systematically and comprehensively 

improve methods and processes that yield an optimal combination of energy 

efficiency, comfort, durability, indoor air quality, and moisture management. 

This definition recognizes quality management as an integral part of achieving 30% whole house 

energy savings. It emphasizes that improvements in energy efficiency must be accompanied by 

commensurate improvements, or at least maintenance, of other key performance attributes of the 

home to reflect a true systems-thinking approach. This definition also reflects the built-in cost 

effectiveness of high-performance quality management as a risk-reduction strategy (comfort, 

durability, indoor air quality, and moisture management) for the builder. And finally, the 

definition encompasses homebuyer expectations of performance—with energy efficiency as just 

one of five performance attributes that any home should provide. 

This definition also establishes the inherent relationship between quality and high performance, 

which is this: Whereas a quality home need not necessarily be a high-performance home, any 

high-performance home MUST be a quality home. For any Building America high-performance 

homebuilder to truly incorporate a systems approach, he or she must also incorporate a quality 

management approach. 

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 and concepts of high 

performance to implementation. 

The package of tools within the Building America quality management approach includes the 

following: 

• Training/Education 

o For builders 

o For individual trades 

o Certifications 

• Operational Evaluation (Modified NHQ42) 

o Paper Review 

 

42 The NHQ is the NAHB Research Center’s National Housing Quality Program, discussed in detail below. Building 

America team leader, IBACOS, modified the NHQ system to include criteria specific to housing performance. 

 49 
o Key Player Interviews 

• Performance-Based Standards 

o Design 

o Specifications 

o Scopes 

• Verification Tools 

o Performance Testing 

o Inspections (Checklists) 

• Feedback Loops. 

Although this package has not been developed from a single source or as a comprehensive 

system, it certainly could be used as a comprehensive quality project management approach. 

Each of these is discussed in detail below. 

Training/Education 

Builder and Subcontractor Training 

Training has been found to be needed throughout the Building America program. Ongoing 

efforts within the industry will be necessary to develop, deploy, and continually update training 

programs to disseminate information from the Building America program if widespread 

implementation is to take place. While Building America has not been specifically charged with 

the development and deployment of training programs, this section discusses some of the 

opportunities, activities, and issues involved with training at the residential construction industry 

level. 

Builders. The starting point for the quality management approach has always been builder 

training. These have included pre-construction training meetings and site training of trade 

contractors. Each Building America team has conducted such trainings, and their work in the 

context of Building America has led to any number of building-science based training programs 

in the industry: 

• The Energy & Environmental Building Association’s Houses That Work training 

program. This public-private training partnership has trained hundreds of builders all across 

the country in the principles of climate-based high-performance building science. Several of 

the Building America teams have certified Houses That Work trainers. Although not 

explicitly portrayed as such, the Houses That Work trainings have many of the elements of 

quality management as listed above. 

• The Environments for Living®43 (EFL) Diamond Class Training. Long-time Building 

America partner, Masco Contractor Services, has developed a new 3-day builder training 

 

43 Environments for Living is a building-science-based, high-performance homebuilding program of Masco 

Contractor Services. The program was developed approximately 5 years ago in a public-private partnership with 

Building America. 

 50 
program, which focuses on the principles of building science and their application in 

production homebuilding. 

• Colorado Built Green® 2005 training. The new three-tier version of this program has 

criteria based specifically on the Building America program and best practices, as well as 

Tier II and III training patterned after Houses That Work. 

• Build IQ Best Practices. An online training company, Build IQ, has been incorporating best 

practices from the Building America program for inclusion in their free and for-fee 

coursework. Build IQ delivers online training to top 100 homebuilders throughout the United 

States, including Pulte Homes, John Laing Homes, Beazer, Morrison, and others. 

• BECT (Building Energy Code Training). Since 1995, BECT has helped the building 

industry keep up with changes in energy codes. The Building Industry Institute (BII) and 

their subcontractor, ConSol, under contract to the California Energy Commission (CEC), 

began a training program for large production builders in California and Nevada. The 

program has improved compliance with energy standards by improving builders’ 

understanding and implementation of the energy codes. 

The BECT program has trained more than 3,000 contractors and subcontractors in the 

California and Nevada area since its beginnings in the mid 1990s. Through the BECT 

program, California is able to train builders in the following: 

o Current codes and issues 

o Upcoming code changes 

o Construction techniques that improve quality of construction 

o Common enforcement issues. 

California’s energy code has always been at the forefront of implementing energy-efficient 

standards in home building. The energy code’s goal in the beginning was to increase energy 

efficiency of a home being built in California every 3 years by approximately 5%. But since the 

energy crisis, the percentage has been increased to 12% in 2001 and 15% in 2005. Having an 

infrastructure in place like the BECT program has greatly facilitated this dramatic change to the 

building industry. 

Training – Trade Contractors. Each Building America team has conducted trade contractor 

training on climate-specific building science and systems thinking. Targeted trades have included 

framing, insulation, and HVAC. The EFL program conducts trade contractor building science 

training for framing and insulation contractors and is developing an HVAC training module. The 

BECT program in California also provides training to subcontractors. 

Training – Certifications. The Building America program has led at least one of its builders to 

develop its own certification related to high performance. Artistic Homes of Albuquerque, New 

Mexico, certifies its entire sales staff under a high-performance training program. The program is 

called the High Performance Homes Sales Specialist. 

It is not clear at this time if certification of high-performance homebuilding skills from a thirdparty group such as the North American Technician Excellence (NATE) or the Building 

Performance Institute (BPI) would be used in the industry. There is time and expense on the part 

of the trade contractor and the individual technician to receive the certification, and this must 

 51 
then be built into the price of doing business, which ultimately gets transferred to the builder. 

There may be a correlation with better-trained technicians and reduced callbacks; however, this 

direct link has not been thoroughly researched or documented. 

Feedback from builders who have participated in the Building America program reveals that one 

of the most difficult aspects of sustaining the delivery of high-performance housing is the 

continuous need for trade training and re-emphasizing the performance targets each trade must 

meet. This, in part, can be attributed to the high turnover in the building industry; however, it 

may be that a certification program for high-performance delivery of various key trade activities 

will be necessary for true transformation of the housing industry. A list of key trade-based 

certifications associated with delivery of high-performance housing can be found in Appendix C. 

Operational Evaluation 

Modified from the National Association of Homebuilders Research Center’s National Housing 

Quality program, the Building America operational evaluation is a two-step process to help 

builders evaluate their own operations. The first is a paper review of all the documentation a 

builder has that is associated with its operations and the actual housing being built. The second is 

an interview with key individuals in the company. A reasonable list of the builders’ primary 

source information for the first part of this evaluation includes the following: 

• Annual operating plan. This includes company mission, vision, organizational values, goals 

for each department, strategic objectives, and reporting and other operational guidelines. The 

annual operating plan supports the long-range strategic plan, by documenting specific actions 

and goals that will help the company achieve the strategic plan. 

• Long-range strategic plan. This includes the direction the company is headed, what types of 

barriers might exist, and how these barriers might be overcome. This document is a roadmap, 

which is made more specific in each year’s annual operating plan. 

• Process maps. These include any diagrammatic or written representation of the workflows 

operationally within the company. 

• Design documentation. This category includes construction drawings, scopes of work, 

written specifications, contracts, field guides, etc., that communicate what should be built by 

the vendors. 

• Operational tools. These include any sort of departmental tools used to facilitate business 

processes. For example, construction schedules or other field tools used by site supervisors to 

assist in the day-to-day management of construction or template letters and reports to assist 

in the standardization of company processes. 

• Training programs. This includes any internally developed or externally developed 

program for continuing education of staff within the builder’s operations. The intent here is 

not to specifically review the content of all training programs, but to evaluate the general 

attitude, approach, depth, and breadth of training activities in the builder’s organization. 

• Human resource manual. This includes company policy, safety programs, benefits, and 

items documenting company culture. 

 52 
• Marketing materials. This includes any type of material used to communicate the builder’s 

message about their product to consumers. 

• Survey mechanisms and results. These include any surveys done by the company or 

outside consultants, which can be for employees, customers, or vendors, or can collect 

regional or local information on competitive information, such as sales prices or volume of 

construction. 

A reasonable list of key builder staff to interview as part of the second step in an operational 

evaluation includes the following: 

• Operations 

• Marketing 

• Sales 

• Purchasing

• Construction 

• Customer Service 

• Human Resources 

• Land Development. 

This two-step process gives a comprehensive understanding of the builder’s current operations. 

This evaluation process could be adopted internally by a builder or externally through the use of 

a consultant in order to identify what areas may need to be addressed if the builder is considering 

transforming their product line to achieve Building America high-performance home technology 

packages. The process is comprehensive, but not overly detailed—it takes approximately 20-30 

hours for one person to work through, once all the data has been assembled. It can identify best 

practices and opportunities without dwelling on minutia. Appendix D contains the latest version 

of the modified NHQ two-step process as developed by IBACOS. 

Performance Standards—Design, Specifications, Scopes 

Quality is often compared to the three-legged stool (the stool is of little use without all three 

legs). In high-performance home-building, quality is only achieved with performance standards 

for design AND materials (specifications) AND installation (scopes). Building America takes 

this premise one step further by stating that many performance standards must be climatespecific; indeed, even lot-specific when local terrain and environments bring with them 

additional challenges, such as extreme slopes, expansive soils, coastal high winds and flooding, 

etc. 

Design and Design Review. An effective means of assuring these goals are implemented during 

the planning stages of a project is through a design review of the project, this can be a key 

instrument in making sure the whole energy system is incorporated in the design. It is highly 

unlikely that a home will be designed singularly around the HVAC system or window orientation 

or its ability to resist heat. However, these are all factors that go into a home and are crucial in 

getting a house to achieve 30% whole-house energy savings. For this purpose, value-engineering 

techniques must be employed to ensure that all the systems in the home can not only be designed 

 53 
to perform at optimum levels but also be coordinated with those involved with actual 

construction of the project to make sure that the homes are built practically and as intended when 

designed on paper. 

Each of the Building America teams has conducted dozens of detailed design reviews, resulting 

in resources such as the Building America Houses That Work climate-specific Best Practices, the 

Houses That Work building profiles, the Noisette Home Performance Standards, the draft Risk 

Assessment Protocol, etc. The common ground among these design standards is that they 

respond to climate-specific protection of the energy efficiency, the comfort, the indoor air 

quality, the durability, and the moisture management of each high performance home. Thus, they 

make up the first leg of the “quality stool”—high performance design. 

Specifications. Specifiers, and subsequently purchasers, rarely take into account the overall 

performance of the home and its systems when making crucial material/component/subsystem 

choices. Standard specifications don’t take into account individual component performance 

variations, much less the impact of single-component choices on assemblies or systems. Various 

Building America projects have addressed this issue. High-performance specifications were 

developed for the EcoVillage Townhome project in Cleveland. Ohio.44 These specifications 

could and should be modified and applied to other high-performance home projects. 

Scopes of Work. Even with intelligent design and the right materials, quality can fall short of 

intended performance without the right installation. Production builders generally rely upon their 

scopes of work to achieve the installation required. But as a rule, these scopes do not reflect 

systems thinking or climate-specific building science. More than one Building America team 

leader has developed project-specific mock-ups (for walls and window installation, for example 

[BSC—EcoVillage, IBACOS - Summerset at Frick Park]) or detailed installation procedures that 

could and should be used by high-performance builders in their scopes. BIRA, in conjunction 

with the Comfortwise program, has developed and posted high-performance specifications for 

several keytrades, including HVAC and insulation. It would not be difficult, for example, to take 

a well-known industry scopes resource, such as the NAHB BuilderBooks “The Scopes of Work 

Program,”45 and develop a customized Building America set of scopes as a comprehensive 

resource that integrates performance and quality. 

Verification 

Verification tools for performance and quality include performance testing and inspection 

checklists. Clearly the first choice is almost always a quantitative test, such as any of the 

following: 

• Using a blower door for measuring air tightness 

• Using a calibrated fan system for measuring for duct tightness 

• Using a flow hood for measuring supply and return airflows at registers and grilles 

 

44 Building Science Corporation. EcoVillage Sample Spec Language. 

www.buildingscience.com/buildingamerica/casestudies/ecovillage_specs.pdf. 2002. 

45 Haas Davenport, Linda. 2000. The Scopes of Work Program: Procedures and Standard to Increase Quality. 

Washington, D.C., BuilderBooks.com. 

 54 
• Using a manometer for room-to-room pressurization 

• Using a digital thermometer to measure room-to-room temperature variation 

• Using a low-e detector to verify glazing properties. 

The beauty of these tests is that quantitative metrics can be established that summarize the 

quality of design, materials, and installation for one or more performance attribute. Most 

performance tests for the residential building industry deal with energy efficiency directly and 

then may be indirectly reflective of other performance attributes, such as indoor air quality and 

comfort. But quantitative tests for other performance attributes, such as moisture management 

and durability, are generally not available, at least not in a cost-effective application. For 

verification of these performance attributes, a detailed inspection checklist and visual inspections 

act as a proxy determination of both quality and performance. 

An important consideration in any quality management approach is the cost of verification. The 

primary determinants of at least the initial costs are the number of homes tested—ranging from 

one initial model home to 100% testing of every home built—and what entity does the testing—

either in-house testing, third-party testing, or some combination of the two. In general, for 

production builders, Building America has recommended a testing strategy similar to the EPA 

ENERGY STAR strategy of 1-in-7 random testing after a period of 100% testing to verify that 

key performance metrics are met on a consistent basis. But more than one Building America 

production builder has determined that either the pace at which they build or their reputation for 

quality (or both) make 100% in-house testing and random 1-in-7 third-party testing the most 

cost-effective strategy in the long run, based on looking at the total costs and total benefits of a 

much more rigorous quality protocol. The Building America Best Practices Guides46 produced 

by Pacific Northwest National Laboratory contain recommendations for testing protocols for 

each climate. In addition, a “SNAPSHOT” performance testing protocol and report process has 

been documented by Building Science Corporation and is included as Appendix E of this report. 

Each Building America team has made up prescriptive checklists to handle non-quantitative 

performance assessment, particularly for performance attributes, such as durability and moisture 

management. While it is difficult to address ALL of the variables that lead to customization of 

these lists—climate, lot, aspect, surrounding local features, building type, etc.—these checklists 

can be referenced as examples of how quality management of high-performance attributes are 

assessed and verified for builders seeking to achieve the Building America “standard.” One of 

the difficulties that builders face with non-quantitative metrics and verification are the questions, 

“How do I know when enough is enough? When is our practice a best practice, substandard, or 

overkill?” Builders MUST use their local conditions and past product history (in terms of 

callbacks, legal claims, 1- and 2-year warranty trends) to intelligently manage durability and 

moisture. Proxy, qualitative tools can be applied—such as infra-red imaging of assemblies, water 

testing, and moisture meter readings—but these approaches have not been documented as part of 

the Building America body of research. 

 

46 Building America Best Practices Series: Volume 3; Builders and Buyers Handbook for Improving New Home 

Efficiency, Comfort, and Durability in Cold and Very Cold Climates. 2005. 140 pp.; NREL Report No. TP-550-

38309. 

 55 
Commissioning 

Building commissioning is a systematic process of ensuring that a building performs in 

accordance with the design intent, contract documents, and the owner's operational needs. As a 

result of the sophistication of building designs and the complexity of building systems 

constructed today, commissioning is necessary, but not automatically included as part of the 

typical design and construction process. Commissioning is critical for ensuring that the design 

developed through the whole-building design process is successfully constructed and operated. 

Building commissioning includes the following: 

• Systematically evaluating all pieces of equipment to ensure that they are working according 

to specifications. This includes measuring temperatures and flow rates from all HVAC 

devices and calibrating all sensors to a known standard. 

• Reviewing the sequence of operations to verify that the controls are providing the correct 

interaction between equipment. 

In particular, building commissioning activities include the following: 

• Engaging a commissioning authority and team 

• Documentation 

• Verification procedures, functional performance tests, and validation 

• Training. 

Building commissioning is not one of the following: 

• Construction observation (punch list) 

• Start-up 

• Testing, adjusting, and balancing (TAB) 

• Final punch-out. 

These activities are individual steps in the systematic process of commissioning, but by 

themselves these activities cannot meet the goals of building commissioning. 

Commissioning HVAC systems is even more important in energy-efficient buildings because 

equipment is less likely to be oversized and must, therefore, run as intended to maintain comfort. 

Also, HVAC equipment in better performing buildings may require advanced control strategies. 

Commissioning goes beyond the traditional HVAC elements. More and more buildings rely on 

parts of the envelope to ensure comfort. 

Commissioning includes evaluating the building elements to ensure that shade management 

devices are in place, glazing was installed as specified, air-leakage standards have been met—

these are the static elements of the building. Commissioning can also evaluate other claims about 

the construction materials, such as VOC emission content and durability. It is important that the 

products that were specified for the building meet the manufacturer's claims (and are appropriate 

for the project.) 

 56 
Continuous commissioning ensures that the building operates as efficiently as possible while 

meeting the occupants' comfort and functional needs throughout the life of the building. 

Continuous commissioning differs from building operation and maintenance. 

Benefits of building commissioning include the following: 

• Energy savings and persistence of savings 

• Improved thermal comfort with proper environmental control 

• Improved indoor air quality 

• Improved operation and maintenance with documentation 

• Improved system function that eases building turn-over from contractor to owner. 

Feedback Loops 

Quality is a process ideally supported by feedback within the corporate structure and across the 

full range of product. Every department—design, construction, purchasing, warranty, sales, and 

marketing—should report performance successes and failures to every department for each and 

every product type, taking full advantage of feedback loops. In reality, many production builders 

set up little incentive for quality of product, erring in favor of quantity of product. But some 

builders are beginning to understand that it is not just how much profit a company can make, but 

how much profit a company RETAINS, once the set-asides for warranty and claims are factored 

in. More than one builder is asking its managers a question like this: 

If we are currently setting aside about $5,000 for each home we build to cover 

warranty and claims, how much quality management can we afford? 

Production builders in today’s hot housing market are generally not having trouble making 

profits, just keeping them. If financial incentives can be created for quality of product, the 

reduction in warranty and claims can be used to finance the quality incentive structure. Feedback 

loops are a key element of any such quality-management approach. 

Quality-Management Summary 

In order to achieve whole-house energy savings of 30% or more, we are managing energy flows 

on, in, and through the structure to such a degree that we must manage the flow of air and 

moisture with equal attention. The links among energy efficiency, comfort, IAQ, durability, and 

moisture are not optional, they are built into the physics that builders face and the expectations 

buyers bring. Likewise, quality management is not an option when building high-performance 

homes. It is a process inherent to systems thinking and systems engineering. Without the qualitymanagement tools to implement the principles of physics and building science, higher 

performance in housing is simply an technical exercise, not a business proposition. 

Building Component Design Details 

Building Enclosure Integrity 

A house is an environmental separator with the function of separating the inside from the 

outside, as required by the local environment and the wishes of its occupants. A house creates an 

 57 
interior environment that is different from the exterior environment. This interior environment 

should be controllable by the occupants in a manner that meets their needs. 

In order to function as an environmental separator, the elements, components, assemblies, and 

sub-systems that comprise a house must meet specific objectives, including the following: 

• Control of heat flow 

• Control of airflow 

• Control of rainwater 

• Control of groundwater 

• Control of water vapor flow. 

Control of Heat Flow 

The key strategy in the control of heat flow is the use of thermal insulation in a manner that 

continuously encloses the conditioned space. If a conditioned space is considered a cube, then 

all six surfaces enclosing the cube are encased by thermal insulation. In the typical home, this 

means both the above- and below-grade walls are insulated, as wells as the attic ceiling/roof 

assembly and the foundation slab. 

Fully insulating a basement slab is also not necessary to meet the 30% savings goal. However, it 

is a recommended approach for all new houses from a moisture-control perspective if basements 

are to be intended for occupancy. Installing carpets and other floor finishes over uninsulated 

concrete basement floor slabs often leads to problems with dust mites and mold in floor 

coverings. 

With wood-frame construction, this means that exterior walls have 2x6 framing where cavities 

are insulated with fiberglass batts, spray-applied cellulose, or low-density spray-applied foams. 

In addition, the exterior 2x6 framing is sheathed with rigid-foam insulating sheathing. 

In general, insulating sheathing is not necessary to meet the 30% savings goal. However, 

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 insulating sheathing. Additionally, the use of insulating sheathing of sufficient thickness 

allows the removal of interior vapor barriers and vapor retarders, thereby enhancing the inward 

drying of the assembly. In other words “double vapor barriers” can be avoided. 

Insulating sheathing also has cost advantages over oriented-strand board (OSB) and plywood 

sheathings when coupled with innovative framing techniques for wind and seismic loadings. 

Reducing heat-flow wood-,frame construction can be accomplished by minimizing the amount of 

framing materials through which conductive heat transfer can occur, increasing the cavity 

thickness to accommodate more thermal insulation and utilizing sheathing materials that provide 

thermal resistance. 

Materials can be reduced at corners and where interior partition walls intersect exterior walls. 

Thermal bridging can be reduced at door and window openings through the use of insulated 

headers and using hangers to eliminate king studs and cripple studs. Stud spacing can also be 

increased to 24-in. spacing and point loading trusses. 

 58 
Increasing cavity thickness to accommodate more thermal insulation can be facilitated in wall 

framing by utilizing thicker framing materials and at the intersection of roof trusses and exterior 

walls through the use of specialized trusses. In all truss and roof assemblies, baffles should be 

installed to prevent the wind washing of thermal insulation and to prevent insulation from 

blocking ventilation in vented-roof assemblies. 

Fenestration has minimum U-values of 0.3 and SHGC values of 0.4 or lower. 

Control of Airflow 

One of the key strategies in the control of airflow is the use of air barriers. Air barriers are 

systems of materials designed and constructed to control airflow between a conditioned space 

and an unconditioned space. The air-barrier system is the primary air-enclosure boundary that 

separates indoor (conditioned) air and outdoor (unconditioned) air. In multiunit/townhouse/apartment construction the air-barrier system also separates the conditioned air 

from any given unit and adjacent units. Air-barrier systems also typically define the location of 

the pressure boundary of the building enclosure. 

The air-barrier system also separates garages from conditioned spaces. In this regard, the airbarrier system is also the “gas barrier” and provides the gas-tight separation between a garage 

and the remainder of the house or building. 

Air-barrier systems keep outside air out of the building enclosure or inside air out of the building 

enclosure depending on climate or configuration. Sometimes, air-barrier systems do both. 

Air-barrier systems can be located anywhere in the building enclosure: at the exterior surface, the 

interior surface, or at any location in between. In Cold Climates, interior air-barrier systems 

control the exfiltration of interior, often moisture-laden, air. On the other hand, exterior airbarrier systems control the infiltration of exterior air and prevent wind washing through cavity 

insulation systems. 

Numerous approaches can be used to provide air-barrier systems in buildings. Rigid materials 

such as gypsum board, exterior sheathing materials like plywood or OSB, and supported flexible 

barriers are typically effective air-barrier systems if joints and seams are sealed. 

Spray-applied foam insulations can be used as interstitial (cavity) air-barrier systems. Dampspray-applied cellulose does not meet the performance requirements of air-barrier materials or 

assemblies ― it is an air retarder. 

The significant advantage of exterior air-barrier systems is the ease of installation and the lack of 

detailing issues related to intersecting partition walls and service penetrations. 

An additional advantage of exterior air-barrier systems is the control of wind washing that an 

exterior air seal provides with insulated-cavity frame assemblies. 

The significant disadvantage of exterior air-barrier systems is their inability to control the entry 

of air-transported moisture into insulated cavities from the interior. As a result, most exterior 

air-barrier systems are insulated on their exterior side with rigid or semi-rigid insulations that are 

not sensitive to wind washing. 

An advantage of interior air-barrier systems over exterior systems is that they control the entry of 

interior moisture-laden air into insulated assembly cavities during heating periods. The 

 59 
significant disadvantage of interior air-barrier systems is their inability to control wind washing 

through cavity insulation and their inability to address the entry of exterior hot-humid air into 

insulated cavities in Hot-Humid Climates. 

Installing both interior and exterior air-barrier systems can address the weakness of each. 

Utilizing framing elements in conjunction with the interior gypsum sheathing can meet the 

requirements of a building-envelope air-barrier system. In this approach, primary reduction of 

air-leakage openings is shared by both the framer and the gypsum-board installer. 

Air leakage at the platform frame floor assembly can be reduced by sealing the rim joist to the 

frame wall or plate below and the sub-floor sheathing above. This is typically accomplished by 

using a continuous bead of sub-floor adhesive to seal the sub-floor sheathing to the rim joist and 

caulking to seal the bottom of the rim joist assembly to the plate below. Gaskets and other seals 

can also be utilized. Where floor trusses or other manufactured wood-product floor system 

components are used (wood I beams), solid rim-joist material installed in a continuous manner 

should be provided to prevent air leakage at the rim-joist assembly. 

Air leakage between the bottom plates of exterior walls and the sub-floor sheathing is controlled 

by sealing the bottom plate to the sub floor. This is typically accomplished by installing a 

continuous bead of sealant or caulk under wall plates. 

Air leakage at floor assemblies where cantilevers occur is also controlled at rim-joist locations. 

Blocking utilizing wood or rigid insulation can be used with both exterior and interior cantilever 

floor assemblies. Where floor-framing members are installed parallel to exterior walls (or garage 

walls), solid rim-joist material can be installed directly over wall plates to provide for air-barrier 

continuity. 

Air leakage through sub-floor sheathing installed over unconditioned spaces, such as vented 

crawl spaces, unconditioned garages, or cantilevered floors over exterior walls, can be controlled 

by sealing all panel joints. 

Tubs, shower stalls, and one-piece manufactured tub/shower enclosures installed on exterior 

walls can provide the single largest source of air-leakage areas when uncontrolled. Rigid 

sheathing material should be installed on the interior surfaces of exterior walls and sealed to 

framing and sub-floor sheathing before the installation of tubs and shower enclosures. Thin, 

non-insulating sheathings can be installed in a manner that allows the installation of interior 

gypsum-board sheathing over sheathing edges without noticeably altering wall thickness. With 

one-piece manufactured tub/shower enclosures, the entire height of the interior surface of 

exterior walls should be sheathed. This usually requires the installation of cavity insulation 

before the installation of the interior sheathing. 

Where fireplaces are installed on exterior walls, air leakage can be as significant as air leakage at 

tubs and shower stalls. Fireplace enclosure framing should be lined on the interior with rigid 

sheathing material. Such enclosures should be considered as small rooms that are conditioned. 

Accordingly, they require a sealed top, bottom, and three sides. Gypsum board, plywood, wafer 

board, and foil-covered pressed paper can provide satisfactory performance when sealed. This 

will also greatly reduce callbacks from cold drafts coming from fireplaces. 

Interior soffit assemblies above cabinetry on exterior walls or adjacent insulated ceilings and 

attics also require air sealing. Where the ends of soffit assemblies or framing boxing in 

 60 
mechanicals intersects exterior walls, the “footprint” of the soffit or framing against the exterior 

wall should be enclosed with sheathing. 

Window and door openings can be sealed by the framer sealing the window or door unit to the 

rough framing with foam, caulk, or other sealant. Alternatively, the drywaller can return the 

gypsum-board interior finish to the window or door unit and seal the joint with caulk. 

Interior utility chases or dead spaces between two closely spaced walls, dropped ceilings, and 

split levels require special attention. Sealing responsibilities are shared between framers and 

drywallers at dropped ceilings and split-levels. Blocking is installed and sealed by the framers; 

gypsum board is installed and sealed by the drywallers. 

Attic access openings located within conditioned spaces should also be sealed, as well as flue 

pipe penetrations. 

Whole-house fans require a cover that can be installed during the heating season in an airtight 

manner. Some whole-house fan units come equipped with airtight covers. Those units that do 

not can have removable covers site manufactured in a similar manner to removable attic access 

covers. 

Control of Moisture 

Control of Rainwater. The fundamental principle of rainwater control is to shed water by 

layering materials in such a way that water is directed downward and outward from the building 

or away from the building. It applies to assemblies such as walls, roofs, and foundations, as well 

as to the components that can be found in walls, roofs, and foundations, such as windows, doors, 

and skylights. It also applies to assemblies that connect to walls, roofs, and foundations, such as 

balconies, decks, railings, and dormers. 

Layering materials to shed water applies to the building as a whole. Overhangs can be used to 

keep water away from walls. Canopies can be used to keep water away from windows, and site 

grading can be used to keep water away from foundation perimeters. 

All exterior claddings pass some rainwater. Siding leaks, brick leaks, stucco leaks, stone leaks, 

etc. As such, some control of this penetrating rainwater is required. In most walls, this 

penetrating rainwater is controlled by a drainage plane that directs the penetrating rainwater 

downward and outward. 

Drainage planes are water-repellant materials (building paper, house wrap, foam insulation, etc.) 

that are located behind the cladding and are designed and constructed to drain water that passes 

through the cladding. They are interconnected with flashings, windows, door openings, and 

other penetrations of the building enclosure to provide drainage of water to the exterior of the 

building. The materials that form the drainage plane overlap each other shingle fashion or are 

sealed so that water flow is down and out of the wall. 

Materials that absorb and store rainwater when it rains and that are located on the outside of 

buildings can create problems. They can act like reservoirs or sponges absorbing and holding 

water when exposed to rain. Stored water can migrate elsewhere and cause problems. Common 

reservoirs are brick veneers, stuccos, wood siding, wood trim, and fiber-cement cladding. 

 61 
The best approach to dealing with reservoirs is to eliminate them or disconnect them from the 

building. Back priming (painting all surfaces, back, front, edges, and ends of wood siding, 

cement siding, and all wood trim) gets rid of the moisture storage issue with these materials. 

Back-venting brick veneers and installing them over foam sheathings disconnects the brickveneer moisture reservoir from the building. Installing stucco over two layers of building paper 

or over an appropriate capillary break, such foam sheathing, similarly addresses stucco 

reservoirs. 

Control of Groundwater. The fundamental principles of groundwater control are to keep 

rainwater away from the foundation wall perimeter and to drain groundwater with sub-grade 

perimeter drains before it gets to the foundation wall. This applies to slabs, crawl spaces, and 

basements. 

Concrete and masonry are sponges – they can wick water through capillarity. This is the main 

reason that damp-proofing (the black tar-like coating) is applied to exterior basement walls. The 

damp-proofing fills in the pores in the concrete and masonry to reduce ground water absorption. 

The damp-proofing is a capillary break. Under concrete-floor slabs, the stone layer combined 

with polyethylene serves a similar function (they act as capillary breaks). Unfortunately, the 

capillary rise through footings is typically ignored. This can be a major problem if foundation 

perimeter wall are finished or insulated. 

In new construction, a capillary break should be installed on the top of the footing between the 

footing and the perimeter foundation wall. This can be done by damp-proofing the top of the 

footing or by installing a membrane at this location. 

The interior insulation and finishing approach must take into account the moisture migrating up 

through the footing. This is best accomplished by installing rigid foam insulation on the interior 

of the assembly to protect the interior finishes. 

The best foams to use have a perm rating of greater than 1 perm for the thickness used. This 

means limiting extruded polystyrene insulation to less than 1-in. thickness for walls (if more than 

1 in. thick, they do not breathe sufficiently) and making sure that the rigid insulation is not faced 

with polypropylene skins or foil facings. Additionally, because foams need to be protected from 

fire, and this is often done with gypsum board, only latex paint should be used on interior 

gypsum finishes (because it breathes). 

Capillary control also applies to slab-on-grade construction and crawl spaces. Monolithic slabs 

need plastic ground covers that extend under the perimeter grade beam and upward to grade. 

Additionally, the exposed portion of slabs must be painted with latex paint to reduce water 

absorption and a capillary break must be installed under perimeter wall framing. 

Control of Water Vapor Flow. The fundamental principle of control of water in the vapor 

form is to keep it out and to let it out if it gets in. The following things are discouraged: 

• The installation of vapor barriers on both sides of assemblies (i.e., “double vapor barriers”) 

• The installation of vapor barriers, such as polyethylene vapor barriers, foil-faced batt 

insulation, and reflective radiant barrier-foil insulation on the interior of air-conditioned 

assemblies 

• The installation of vinyl wall coverings on the inside of air-conditioned assemblies 

 62 
• The installation of polyethylene vapor barriers on the interior of internally insulated 

basements. 

The following things are encouraged: 

• The construction of assemblies that are able to dry by diffusion to at least one side and, in 

many cases, to both sides 

• The ability to use insulating sheathings in Cold Climates without the creation of “double 

vapor barriers” 

• The ability to use of damp-spray insulations in Cold Climates with insulating sheathings 

without the creation of “double vapor barriers.” 

Specific Recommendations 

• Soil surfaces shall be graded away from below-grade envelope surfaces. 

• Materials next to below-grade envelope surfaces shall be free-draining and shall connect to a 

sub-grade drainage system through a filter media that will prevent fines build-up in the 

drainage system. 

• A clay cap or other water-flow-resistant surface layer shall be installed to prevent surface 

water from draining into the free-draining material next to below-grade envelope surfaces. 

• Below-grade surfaces shall be provided with a damp-proofing layer or coating that will be 

effective as a capillary break. 

• All surfaces subject to wind-driven rain or snow shall be provided with a drainage plane or 

layer that will prevent rain wetting of internal materials. 

• Indoor relative humidity shall be maintained at the center of the room or as low as necessary 

to keep the room air next to cool/cold surfaces at less than 70% relative humidity. 

• All building envelope assemblies should include at least one air barrier and one vaporretarder surface. 

• All crawl-space assemblies should have a continuous impermeable ground cover that 

functions as both an air barrier and vapor retarder. 

• Provide air-barrier systems that control air movement from the interior. 

• Locate vapor diffusion retarders toward the interior of building assemblies and avoid vapor 

diffusion retarders toward the exterior of building assemblies. Where low permeance 

exterior sheathings are utilized, temperature of condensing surfaces under heating conditions 

should be controlled (use of insulating sheathings, external insulation), as well as interior 

vapor pressures. 

• Provide secondary air barriers that control wind washing from the exterior. 

• Control interior relative humidities during the coldest portion of the heating season (maintain 

below 35%). 

• Allow wet or moist materials used in construction to dry toward the exterior. 

 63 
Envelope Systems 

Foundation Systems 

The function of a foundation system is to hold up the building. This involves facilitating the 

transfer of loads from above grade to the ground. Foundation systems, depending on their 

configuration and location, may also have to control other factors, such as heat flow, airflow, 

rainwater, groundwater, and water-vapor flow. 

Slab on Grade 

Structure. In Cold Climates the primary slab-on-grade approach involves stem wall and footing 

construction because of the historic necessity of locating the bottom portion of the foundation 

below the frost depth. Shallow frost-protected foundation approaches have proven to be 

incompatible with typical tract construction practices; horizontal insulation projections are prone 

to damage during the construction process. 

Insulation and Air Infiltration. The perimeter of the concrete slab must be thermally isolated 

from both the stem wall and the ground below. In Cold Climates, additional insulation is also 

necessary to provide thermal comfort and this necessitates full-height thermal insulation installed 

internally on the stem wall. This thermal insulation extends from the top of the footing to the 

underside of the slab. A sill gasket also provides an air seal between the foundation and the 

frame structure on top, as well as a soil gas seal between the slab and the stem wall. 

Water Management: Drainage, Vapor Diffusion. As in all foundation systems the perimeter 

grade must slope away from the foundation to reduce the saturation of ground adjacent the 

structure. With stem-wall slab construction footings, stem walls do not need to be damp-proofed 

if the slab is isolated with both a capillary break and vapor barrier from both the ground and the 

stem wall. The sill gasket functions as the primary capillary break between the stem wall and the 

frame structure. A polyethylene-sheet membrane vapor barrier should be installed in direct 

contract with the concrete slab ― above any thermal insulation under the slab. 

Interaction with Mechanical Systems. Excessive long-duration interior negative pressures 

should be avoided. A depressurization limit of 5 Pascals is recommended for continuously 

operating exhaust appliances. A depressurization limit of 20 Pascals is recommended for 

intermittent-operating exhaust appliances. Only sealed-combustion appliances should be 

installed within the pressure boundary of the building enclosure. Passive sub-slab ventilation is 

recommended to reduce atmospheric air-pressure soil-gas drivers. 

Crawl Space 

Structure. In Cold Climates, the primary crawl space approach involves conditioned crawlspace construction. Vented crawl spaces are energy inefficient compared to conditioned crawl 

spaces and lead to comfort problems (cold-floor complaints) and freezing pipes. 

Insulation and Air Infiltration. The perimeter of crawl spaces must be insulated typically to 

the same level of thermal resistance of the frame wall above. Interior rigid insulation is the 

insulation system of choice because it is not water sensitive. The interior location is preferred 

from both a constructability perspective and insect-resistance perspective. 

 64 
This thermal insulation extends from the top of the footing to the underside of the floor framing. 

A sill gasket provides an air seal between the foundation and the frame structure. 

Water Management: Drainage, Vapor Diffusion. As in all foundation systems the perimeter 

grade must slope away from the foundation to reduce the saturation of ground adjacent the 

structure. All below-grade surfaces in ground contact should be damp-proofed. A continuous 

sealed air barrier and vapor-barrier ground cover should be installed. If the interior crawl space 

grade is below the exterior grade, a perimeter drain system is required. This perimeter drain 

works best when located on the exterior of the foundation assembly. 

Interaction with Mechanical Systems. Excessive long-duration interior negative pressures 

should be avoided. A depressurization limit of 5 Pascals is recommended for continuously 

operating exhaust appliances. A depressurization limit of 20 Pascals is recommended for 

intermittent-operating exhaust appliances. Only sealed-combustion appliances should be 

installed within the pressure boundary of the building enclosure. Passive sub-ground cover 

ventilation is recommended to reduce atmospheric air pressure soil gas drivers. 

Conditioning of the crawl space should be accomplished by supplying conditioned air to the 

crawl space either via a dedicated duct or via transfer air from the house where a continuously 

operating exhaust fan is used as the pressure driver. 

Basement 

Structure. In Cold Climates, the primary basement construction approach involves perimeter 

cast-in-place concrete foundation walls over strip footings. The footings are located below the 

frost depth. Shallow frost-protected foundation approaches have proven to be incompatible with 

typical tract construction practices; horizontal insulation projections are prone to damage during 

the construction process. 

Insulation and Air Infiltration. The perimeter of the basement assembly must be insulated full 

height from the top of the footing to the top of the foundation wall. Interior rigid insulation is the 

insulation system of choice because it is not water sensitive. The interior location is preferred 

from both a constructability perspective and insect-resistance perspective. Additionally, thermal 

comfort issues require insulation below the basement slab over the entire surface area of the 

basement floor. 

A sill gasket provides an air seal between the foundation and the frame structure. 

The interior surface of the rigid insulation must be protected from fire. 

Water Management: Drainage, Vapor Diffusion. As in all foundation systems the perimeter 

grade must slope away from the foundation to reduce the saturation of ground adjacent the 

structure. All below-grade surfaces in ground contact should be damp-proofed. A capillary 

break should also be installed over the top of the strip footings, isolating the perimeter concrete 

foundation wall from the ground. A polyethylene-sheet membrane vapor barrier should be 

installed in direct contract with the concrete slab ― above any thermal insulation under the slab. 

Interaction with Mechanical Systems. Excessive long-duration interior negative pressures 

should be avoided. A depressurization limit of 5 Pascals is recommended for continuously 

operating exhaust appliances. A depressurization limit of 20 Pascals is recommended for 

intermittent-operating exhaust appliances. Only sealed-combustion appliances should be 

 65 
installed within the pressure boundary of the building enclosure. Passive sub-slab ventilation is 

recommended to reduce atmospheric air pressure soil gas drivers. 

Building Enclosure Integration Strategies 

Walls 

The function of wall systems is to provide environmental separation between the interior and 

exterior, as well as to transfer wind and seismic loads to the foundation. And, similarly, walls 

transfer loads from the roof to the foundation. As part of the provision for environmental 

separation, wall systems have to control heat flow, airflow, rainwater, and water vapor flow. 

Structure. In Cold Climates, the primary structural approach is site-built wood frame utilizing 

engineered elements, such as prefabricated lintels, headers, and sheet goods, such as OSB, 

plywood, and gypsum wallboard. 

Resistance to shear loads as a result of wind and seismic events must be provided. The choice of 

construction or framing approaches addressing shear loads should reflect the local conditions. 

For example, houses constructed in low-wind zones can be constructed with wood frame 

assemblies with non-structural sheathings and metal cross braces or wood “let-in” braces. A 

similar home built in a higher wind zone, such as in a coastal wind zone or built in a more severe 

seismic zone, may have to be constructed with structural sheathing or inset shear panels. 

The principle means of controlling lateral loads are as follows: 

• metal cross braces 

• wood “let-in” braces 

• structural sheathing such as plywood or OSB 

• proprietary shear panels. 

Insulation and Air Infiltration. The optimum approach to insulation involves 2 x 6 advancedframe walls with insulating sheathing replacing OSB or plywood sheathing. Cavity insulation is 

either unfaced fiberglass-batt insulation or damp-sprayed cellulose. 

Air infiltration control is provided by an air barrier. An interior air barrier is used, specifically 

interior gypsum sheathing combined with framing elements, such as draft-stopping and firestopping components. 

Water Management: Drainage, Vapor Diffusion. Rainwater management is provided by 

using the insulating sheathing as a drainage plane and integrating window and doors with the 

insulating sheathing to provide drainage-plane continuity. 

Vapor diffusion is addressed on a location by location basis via the thermal resistance of the 

insulating sheathing. No interior vapor barrier is installed; however, the temperature of the 

condensing surface is controlled by increasing the thermal resistance of the insulating sheathing. 

As the average outdoor temperature of the three coldest months decreases, the thermal resistance 

of the insulating sheathing increases. For example, in Chicago, R-5 (or 1-in.) insulating 

sheathing is used, whereas in Minneapolis, R-10 (or 2-in.) insulating sheathing is used (Figure 17 

and Figure 19). 

 66 
Interaction with Mechanical Systems. The tighter the building enclosure, the greater the 

pressure differential created with exhaust appliances. The use of an air barrier results in a tighter 

building enclosure. 

Excessive long-duration interior negative pressures should be avoided. A depressurization limit 

of 5 Pascals is recommended for continuously operating exhaust appliances. A depressurization 

limit of 20 Pascals is recommended for intermittent-operating exhaust appliances. Only sealedcombustion appliances should be installed within the pressure boundary of the building 

enclosure. 

Floors 

The function of floor systems is to provide environmental separation between the interior and 

exterior where they intersect the exterior enclosure, as well as to transfer wind and seismic loads 

to the foundation by functioning as a diaphragm and similarly to transfer loads from the roof to 

the foundation. As part of the provision for environmental separation, floor systems have to 

control heat flow, airflow, rainwater, and water-vapor flow. 

Structure. In Cold Climates, the primary structural approach is site-built wood framing utilizing 

engineered elements, such as prefabricated I-joists and sheet goods, such as OSB. 

Insulation and Air Infiltration. The optimum approach to insulation involves using sprayfoam insulation on the interior of the rim-joist assembly. An alternative approach in severe Cold 

Climates is to use a prefabricated insulated rim joist. 

Air-infiltration control is provided by an air barrier. The air barrier is the rim-joist assembly 

itself sealed to the framing elements above and below using sealant or spray-foam insulation. 

Water Management: Drainage, Vapor Diffusion. Rainwater management is provided by 

using insulating sheathing installed exterior to the rim joist as a drainage plane and integrating 

this with the insulating sheathing of the frame assembly, either above or below the floor system 

to provide drainage-plane continuity. 

Vapor diffusion is addressed on a location-by-location basis via the thermal resistance of the 

insulating sheathing installed exterior to the rim joist. No interior vapor barrier is installed; 

however, the temperature of the condensing surface is controlled by increasing the thermal 

resistance of the insulating sheathing. As the average outdoor temperature of the three coldest 

months decreases, the thermal resistance of the insulating sheathing increases. For example, in 

Chicago, R-5 (or 1-in.) insulating sheathing is used, whereas in Minneapolis, R-10 (or 2-in.) 

insulating sheathing is used (Figure 17 and Figure 19). 

Interaction with Mechanical Systems. The tighter the building enclosure, the greater the 

pressure differential created with exhaust appliances. The use of an air barrier results in a tighter 

building enclosure. 

Excessive long-duration interior negative pressures should be avoided. A depressurization limit 

of 5 Pascals is recommended for continuously operating exhaust appliances. A depressurization 

limit of 20 Pascals is recommended for intermittent-operating exhaust appliances. Only sealedcombustion appliances should be installed within the pressure boundary of the building 

enclosure. 

 67 
Roof / Ceiling / Attic 

The function of roof/attic systems is to provide environmental separation between the interior 

and exterior, as well as to transfer wind and seismic loads to the foundation by functioning as a 

diaphragm. As part of the provision for environmental separation, floor systems have to control 

heat flow, airflow, rainwater, and water-vapor flow. 

Structure. In Cold Climates, the primary structural approach is site-built wood framing utilizing 

engineered elements, such as prefabricated roof trusses and sheet goods, such as OSB and 

plywood. 

Insulation and Air Infiltration. The optimum approach to insulation involves blowing 

insulation on the top surface of ceiling gypsum board. This ceiling insulation level is maintained 

throughout the entire plane of the ceiling extending to the perimeter walls. Roof trusses are 

constructed in such a manner as to maintain the thickness of ceiling insulation directly above the 

top plates of the exterior wall framing. Baffles are installed to control wind washing. 

Air-infiltration control is provided by an air barrier. The ceiling gypsum board is installed to 

function as an air barrier. Dropped ceiling areas are draft-stopped, ceiling light fixtures are 

selected to be airtight, and all penetrations through plates are air sealed. 

Water Management: Drainage, Vapor Diffusion. Traditional roofing materials such as 

shingles are used to provide rainwater management at the roof deck. 

Vapor diffusion is handled by providing roof/attic ventilation. 

Interaction with Mechanical Systems. The tighter the building enclosure, the greater the 

pressure differential created with exhaust appliances. The use of an air-barrier ceiling assembly 

results in a tighter building enclosure. 

Excessively long-duration interior negative pressures should be avoided. A depressurization 

limit of 5 Pascals is recommended for continuously operating exhaust appliances. A 

depressurization limit of 20 Pascals is recommended for intermittent operating exhaust 

appliances. Only sealed combustion appliances should installed within the pressure boundary of 

the building enclosure. Passive sub-slab ventilation is recommended to reduce atmospheric air 

pressure soil gas drivers.

 68 
Figure 17. Example of building envelope details for Chicago, Illinois 

69 
Figure 18. Example of building envelope details for Denver, Colorado 

70 
Figure 19. Example of building envelope details for Minneapolis, Minnesota 

71 
Space Conditioning and Ventilation Systems 

Forced Air 

Forced-air heating and cooling systems are the most predominant type of system in today’s 

residential new-construction market. This is driven primarily by the market for central air 

conditioning. According to census data, 77% of the homes constructed from 1990 to 1997 had 

central electric air conditioning. Central natural gas-fired furnaces were used in 47% of the new 

homes. 

To accomplish the target of 30% whole-house energy savings in the Cold Climate region, a 

direct-vent condensing furnace is recommended. Direct-vent furnaces use outdoor air for 

combustion and can be easily located within the conditioned space. This was the approach taken 

for each of the case studies provided. 

Induced-draft furnaces draw combustion air from the surrounding space and for “unusually tight 

construction” (which all 30% homes should be), outside make-up air must be ducted in. These 

outside air ducts can lead to complaints about cold drafts and defeat many of the objectives of a 

tight building envelope. Induced-draft furnaces are not recommended for 30% whole-house 

energy-savings homes. 

Locating the forced-air system (air-handler equipment and ducts) within the conditioned space is 

important to whole-house performance. By locating the furnace within the thermal envelope, not 

only is the leaky and minimally insulated cabinet within the conditioned space, but all of the 

ductwork is as well. This minimizes the system inefficiencies associated with air leakage and 

thermal losses. 

Methods for locating the duct system within the conditioned space include the use of open-web 

floor trusses, dropped ceilings and soffits, modified roof trusses, or an unvented or 

“cathedralized” attic.47 The “best” method depends upon the house plan, the type of foundation, 

and the builder’s preferences. 

Homes with basements typically have the equipment located in the basement with ducts that 

serve the first floor via floor registers. Duct chases should be provided in the first-floor plan to 

bring supply air to and return air from the second floor. The use of open-web floor trusses 

provides spaces for ducts to run to serve second-floor registers or up into interior walls for high 

wall supply registers. Space-conditioning ducts should not be run in outside walls and return 

ducts should not be panned. Central hard-ducted returns are recommended with passive return 

air paths, such as jump ducts or transfer grilles from bedrooms. 

Homes with slab foundations commonly have ducts in the attic with ceiling supply registers. For 

these homes, the opportunity to bring the ducts into the conditioned space with dropped ceilings 

and/or soffits should be considered first.48 Alternatively, Building America teams have also 

employed unvented attics and modified roof trusses. 

 

 

47Hedrick, R., Home Builders Guide to Ducts in the Conditioned Space, 

www.energy.ca.gov/reports/2003-11-17_500-03-082_A-16.pdf

48 McIlvaine, Beal, and Fairey. Design and Construction of Interior Duct Systems. 

www.fsec.ucf.edu/bldg/baihp//pubs/interior_ducts.pdf. 

72 
With the high-performance envelope measures described in previous sections, the annual cooling 

load for homes in the Cold Climate region will most likely be modest. Thus, the efficiency of 

the air-conditioning system has a small impact on the whole-house energy performance. Airconditioning systems with efficiencies beyond the new NAECA49 minimum efficiency of SEER 

13 are not necessary to meet the 30% whole-house goal. However, the availability of incentives 

for higher efficiency equipment and/or the specific design and loads of the home could make 

higher efficiency equipment an appropriate consideration. 

Furnaces or air handlers with “variable-speed” brushless permanent-magnet DC motors are 

recommended.50 These motors are more efficient at lower speeds than the more common 

permanent split-capacitor (PSC) type motors. Efficiency at lower-speed operation is increasingly 

important in systems with multiple gas-firing stages, enhanced dehumidification capability 

during cooling, air-cleaning equipment, or integrated ventilation. 

All space-heating and cooling systems should be sized according to the procedures described in 

ACCA Manuals J and S.

Hydronic 

Where air conditioning is not necessary or radiant heating is desired, a boiler can be considered. 

For space heating, standard boiler efficiencies are not as high as condensing-furnace efficiencies. 

Condensing boilers are available from a limited number of manufacturers, but they are expensive 

and their performance has not been thoroughly evaluated by the Building America teams. Never 

the less, when system performance is considered, including the hydronic distribution system and 

the use of the boiler to supply domestic hot water needs as well, the high efficiency (85%-87% 

AFUE) non-condensing boiler with a power vent or direct vent may be a reasonable choice. 

The use of boilers and domestic hot water heaters for space heating is discussed further in the 

section of this report entitled Combination Systems – Space and Water Heating. 

Ventilation 

In addition to point-source exhaust systems that are ducted to the outdoors for bathrooms and 

kitchen ranges, a whole-house mechanical ventilation system that is capable of meeting the 

specifications of ASHRAE Standard 62.2 is recommended. For Cold Climate homes, there are 

several approaches with varying levels of initial cost and complexity.51 The following three 

systems were used in the case studies provided: 

• a balanced system using a heat-recovery ventilator (Kacin Homes, Pittsburgh, and Eastern 

Dakota, Grand Forks) 

• an exhaust-only system with low-sone bath fans rated for continuous duty (Claretian, 

Chicago) 

 

49 NAECA refers to the National Appliance Energy Conservation Act established in 1987. 

50 Pigg, S. The Electric Side of Gas Furnaces, Home Energy, November/December 2003, pp. 24-28. 

51 Whole-House Ventilation Systems: Improved Control of Air Quality. Building Technologies Program, Office of 

Energy Efficiency and Renewable Energy (EERE) (Brochure). 2002. 6 pp.; NREL/BR-840-26458; DOE/GO102002-0778 

73 
• a supply-only system integrated with a dehumidifier and the central air-handling unit (DR 

Horton, Reno). 

Each system has different features and benefits, and there is clearly no “best” approach that 

applies for all builders and homebuyers in the Cold Climate. 

Balanced-heat or enthalpy-recovery systems have the advantages of heat recovery from the 

exhausted air, but have the highest initial cost. The extent that these systems are marketable to 

potential home buyers is important to the selection of this approach. These systems also provide 

higher outside flow rates (100 cfm or higher) than called for by ASHRAE 62.2 (60 cfm for a 

three-bedroom, 3000-ft2

 home). Homeowners need to understand the operation and importance 

of proper maintenance for these systems to perform properly. 

It has been demonstrated that exhaust-only systems are the lowest in initial cost and simplest to 

implement.52 However, the outside air enters the home unfiltered and through unknown 

locations. The circulation of the ventilation air throughout the home is also dependant upon the 

house plan, location of the exhaust fan(s), and the frequency of operation for the home’s central 

air handler. 

Supply-only systems provide the ability to filter the air, but pressurize the space. As stated in 

ASHRAE 62.2, pressurizing the space may be unacceptable in Cold Climates and if delivered 

directly to rooms without tempering, can cause thermal discomfort. Nevertheless, with adequate 

control of indoor humidity levels, a supply-only system with a passive outside air inlet to the 

central air-handler’s return with appropriate dampers and controls has been successfully 

employed in Building America homes. It’s important that the outside air is sufficiently mixed 

with and tempered by return air to avoid damaging condensation in the furnace’s heat exchanger 

and to avoid comfort complaints. As with all mechanical systems, it is also important that the 

system is properly commissioned.53 

Air Distribution 

As discussed in the section of this report on System Design Approach, at the 30% improvement 

level, a number of general requirements apply to design of the forced-air distribution system: 

• Design should be in accordance with ACCA Manual D 

• Ductwork should be located within the thermal envelope of the house or in some climate 

zones buried within the attic insulation 

• Ducts should not be located in exterior walls 

• Ducts must be air-sealed using UL 181-approved mastic or equivalent for the particular duct 

type 

• “Panning” between joists and the use of stud cavities for supply or return air is not 

recommended 

• Ducts may be of galvanized sheet metal, duct board, or flex duct 

 

52 Furnace Fan Penalty, Energy Design Update, June 2005. 

53 Ventilation System Installation and Commissioning Guide. 2004. 6 pp; Record No. 35395 

74 
• There must be continuity of the vapor barrier on insulated ducts not running inside 

conditioned spaces 

• Locate ducts within an insulated, non-vented, conditioned crawl space or basement 

• Locate within an insulated “cathedralized” attic 

• Locate in open-web floor trusses 

• Develop chase walls to accommodate duct risers 

• Design closets inside the conditioned space for locating the air handler in houses using slabon-grade construction. 

While the distribution system is important from an energy perspective, there are also health, 

safety, and IAQ issues to be considered. The following sections briefly discuss each, with 

recommended solutions. 

Seal forced-air distribution systems. Leaky duct systems, in addition to the energy losses thus 

introduced, may result in indoor-outdoor pressure imbalances that generate significant air 

leakage through the building envelope. For the 30% improvement house, extensive duct sealing 

is typically required. For metal ducts, UL 181 mastic is the only acceptable sealing method; for 

duct board, UL 181 tapes are accepted; and for flex duct a combination of UL 181 mastic and 

strap ties should be used. The targets for total duct leakage is 5% of the high-speed system 

cooling airflow in CFM, as tested at 25-PA reference pressure. To further reduce duct leakage, 

do not pan joists or use stud cavities for supply or return air. It is virtually impossible to seal 

building cavities properly to achieve the target tightness for forced-air systems. 

Isolate the HVAC system from areas with potential pollutants. One of the most potentially 

hazardous IAQ problems arises when return ducts run through garage spaces where the 

opportunity exists to draw CO from automobile exhausts or other pollutants from hazardous 

chemicals often stored in the garage into the duct system and redistribute it throughout the house. 

Locating the HVAC unit in the garage is not recommended in the 30% improved houses, but it is 

not always possible to relocate the air-handling unit. If the air handler and return-air ducts must 

be located in the garage, any return-air ductwork and the air handler should be thoroughly sealed 

with UL 181 mastic, with a target leakage between the duct system and the garage of 0 

CFM@25 PA. This yields the least possible opportunity for bringing garage air into the return 

system. 

Pressure Balance the System. Pressure imbalances can cause air movement through the 

envelope when the HVAC system is operating, wasting energy, and potentially causing moisture 

problems. Imbalanced airflows can also cause room-to-room or floor-to-floor temperature 

differences, leading to comfort complaints. Finally, imbalanced airflows can draw unwanted 

pollutants into the house, causing indoor air-quality problems. One key factor in eliminating 

room-room and indoor-outdoor pressure imbalances is the adequacy of the return-air path. In 

homes with individual-room ducted returns this is generally not a problem. Individual-room 

ducted return systems are historically typical in colder climates, but are losing favor because of 

their costs. From a cost-effectiveness standpoint, a well-designed central-return system with 

individual-room pressure relief is considered the standard for the 30% improvement house. To 

qualify as well-designed, the return system must incorporate adequate relief from each room 

where entry doors may be closed. Thus, return-air recommendations include the use of ceiling 

75 
“jump ducts,” or transfer grills located in the walls. Door undercuts are generally not considered 

to be acceptable because they are often inadequate in area and/or blocked by the installation of 

carpeting. One important consideration in the installation of “jump ducts” or transfer grilles is to 

maintain a satisfactory acoustic separation between spaces. This is typically accomplished by 

the use of flex duct, duct lining with sound-absorbent material, a slightly circuitous path, or some 

combination of these strategies to block sound transmission. 

Supply-air Register Selection and Placement. The distribution of the heating or cooling air 

stream from the supply register to the return point is critical to maintaining comfort conditions 

within the room. In the 30% improvement house, envelope insulation (including window Uvalue and SHGC) and air sealing have been improved to such an extent that basic comfort needs 

are more easily met by the HVAC System. In particular, envelope surface temperatures are 

moderated to a considerable degree, which results in reduced radiant heat loss (or gain) to room 

occupants, improving comfort conditions. Similarly, solar gains through low-SHGC windows 

are reduced, considerably improving cooling-season comfort conditions. With good air sealing, 

houses are much less drafty than those built to older construction standards. 

All these reduced loads and improved comfort conditions mean that room heating/cooling air 

volumes (at typical supply temperature) may be reduced. If typically sized registers are used, 

discharge velocities are reduced, and the air has less “throw” within the room. This is a new 

operating region for forced-air systems and presents a number of challenges to achieving a 

proper design for good comfort conditions. 

In conventionally built housing in Cold Climates, supply registers are typically located in the 

floor or at the baseboard on the outside wall and underneath windows. When thermal losses are 

high and drafts are strong, such locations are logical. In the cooling season, this low position 

requires significant velocity and throw to engage the entire mass of air and to provide even 

temperatures throughout the room. 

With the lower loads of the 30% improved house, such register locations may not be necessary. 

There are good reasons to shift supply registers out of these low floor positions. Of primary 

importance is to avoid blockage by furniture and draperies for better cooling performance. High 

wall or ceiling positions avoid this blockage potential and provide better cooling performance. 

To maintain comfort in the heating season, it is critical to properly select registers based on 

throw characteristics and the volume of air being delivered to the room. This may require 

designing at the upper limits of recommended face velocities and the purchase of “non-standard” 

register sizes. It may also require the use of registers with manually operable vanes to fine-tune 

air flow for optimal comfort. 

In general, high sidewall applications have been used where the register is directed at the wall of 

dominant heat loss or gain (usually the wall with windows or glass doors) and the register is no 

more than 12 -13 ft away. Ceiling diffusers with curved blades to help direct the airflow along 

the ceiling can be used where the wall opposite the dominant load exceeds 13 ft. 

Research is currently underway in the Building America Program to understand the issues of air 

distribution in high-performances houses and to develop recommendations for supply and return 

apertures to achieve the best comfort conditions consistent with a highly energy-efficient system. 

76 
There are many issues to consider including the following: 

• Register location and discharge pattern 

• Discharge velocity 

• Discharge temperature 

• Effect of return location 

• Stratification and mixing patterns 

• Part load operation, H/C variation 

• Impact of zoning systems 

• Solar load variability 

• Buoyancy issues 

• Sound issues 

• Register/nozzle configurations 

• Register approach conditions – boots 

• Dampening and control. 

The recommendations that are developed from these ongoing investigations will enhance the 

current recommendations for houses achieving 30% whole-house savings and will likely be 

critical for houses at the 40% and greater improvement levels. 

Duct Insulation. If ducts cannot be brought within conditioned spaced, supply ducts should be 

insulated to R-8 minimum and return ducts to R-4 minimum. Research by the Building America 

Team CARB54 has supported code credits for ducts in Hot-Dry and Mixed-Dry Climates that are 

buried in loose-fill attic insulation. This strategy may be applicable to areas in the Cold Climate 

zone with low relative humidity during the cooling season. This strategy should not be used in 

sections of the Cold Climate zone with high relative humidity in the cooling season because 

condensation can form on the outside of the duct vapor barrier and cause moisture problems in 

the home. Similarly, it is critical to make sure all metal fittings are well insulated to avoid 

condensation. 

Dehumidification 

Dehumidification of basement spaces in Cold Climates is not necessary if basements are 

correctly constructed and insulated. However, dehumidification is a powerful technology to 

repair and rehabilitate problem basement assemblies. 

 

54 Dianne Griffiths et al. Insulation Buried Attic Ducts – Analysis and Field Evaluation Findings. American Council 

for Energy-Efficient Economy (ACEEE). 2004 ACEEE Summer Study on Energy Efficiency in Buildings. Pacific 

Grove, CA. August 23, 2004 

77 
Mechanical, Electrical, and Plumbing Systems 

Lighting 

The development of improved efficiency in residential lighting has been pursued in a number of 

prototype homes. These have ranged from the simple substitution of screw-in conversion CFL 

lamps used in conventional fixtures to a High-Performance Lighting (HPL) approach using a full 

complement of hard-wired, dedicated compact and linear fluorescent fixtures. In addition to 

providing excellent light quality, a key objective of several HPL prototype installations has been 

to provide as much of the basic ambient lighting and key task lighting in the home as possible. 

The reason for this emphasis is to maximize the efficient light content of the house and minimize 

the discretionary (usually incandescent) portable lighting provided by the homeowner. This 

approach yields the greatest reliable lighting energy-use reduction. 

With the current cost of good quality hard-wired fluorescent fixtures (those with electronic 

ballasts and good optics), the HPL approach does not appear to be cost effective for a house at 

the 30% improvement level. The industry is still lacking a family of more affordable hard-wired 

fluorescent fixtures that meet production-builder price points. Important steps have been taken 

in this regard, most notably the development by Lawrence Berkeley Labs, the California 

Lighting Technology Center, and Lithonia of the recessed downlight twin package. This 

package offers a pair of good quality recessed downlight at a reduced manufacturing and 

installation cost. More innovative development of this type is needed across the board for HPL 

cost reductions. Simple screw-in CFL substitution is a viable strategy at the 30% level; however, 

there are questions as to the persistence of energy savings because the homeowner is free to 

replace the CFL with a traditional incandescent light bulb. A website that discusses lighting 

options in detail has been developed and is located at www.ibacos.com/hpl1.html. 

The following are near-term energy-savings opportunities for new homes. In some cases, these 

involve newly commercialized products that are just now entering the market, while in other 

cases these represent systems show great promise but need further refinement and field-testing: 

• Lamps with color-rendition index (CRI) of 80 or higher and a color temperature (CT) of 

3000 degrees Kelvin 

• Screw-in replacement CFL bulbs with instant-on electronic ballasts. Some are available to 

work with conventional dimmers 

• High-quality, high-output residential-grade CFL downlights for kitchens and hallways 

• Linear fluorescent bathroom vanity strips (vertical and/or horizontally mounted) 

• Bathroom-occupancy sensors with integrated LED nightlight 

• LED porch lighting 

• LED exterior security luminaire 

• High-output LED walkway lighting 

• Evaluation of energy-savings potential from incandescent dimming. 

78 
Residential Lighting Controls. Residential lighting controls represents a significant 

opportunity for energy savings. Lighting controls generally refers to technologies that turn off 

(or turn down) lighting systems when they are not needed. Examples include occupancy sensors, 

photo sensors, dimmers, and timers. 

Technologically, residential controls have improved greatly over the past several years, both in 

terms of the types of controls options available, as well as their quality and functionality. 

Because the cost of these systems is decreasing by increased demand for commercial 

applications, they become increasingly attractive for cost-effective residential applications. 

Recognizing these technological and market advances, as well as the potential energy savings of 

these technologies, energy-code officials have begun to look more closely at residential lighting 

controls. The new 2005 Title 24 building code in California, which will go into effect on 

October 1, 2005, includes strong incentives for homebuilders to utilize occupancy sensors, photo 

sensors, and dimmers. In fact, many market watchers now anticipate that homebuilders will 

choose lighting-control alternatives over energy-efficient luminaries to comply with this new 

code because the controls approaches are often more cost-effective. 

Major Appliances 

At the present time, the best practice recommendations for the 30% improvement house is to use 

ENERGY STAR-rated appliances. Within the ENERGY STAR-rated offerings, there are 

differences in performance levels, but these are probably not of significance at the 30% 

improvement level. It is also recommended that best-in-class appliances for non-ENERGY 

STAR-rated appliances be installed or recommended for purchase by the homeowner if not 

provided by the builder. 

Program for Off-peak Operation. While not a mechanism for direct-source energy reduction, 

peak-load shifting is a beneficial strategy from a consumer-utility cost perspective where timeof-use rates are in effect; peak-load shifting and can have electric utility system benefits by 

helping to reduce the need for peak-power plants. The cost of energy consumption for appliances 

can be reduced by operating appliances during off-peak hours and refraining from or minimizing 

their use (especially simultaneous use) during peak hours. 

For example, using Whirlpool’s energy-management system for stand-alone Time-of-Use (TOU) 

appliances delays the operation of the dishwasher, washing machine, and dryer until the energy 

prices are lower (off-peak rate). An LED lets the consumer know if the rate is currently on- or 

off-peak. To delay until off-peak, the consumer can press a button and another LED illuminates 

to let them know that this appliance will start at a later time. 

An alternative strategy is to minimize the amount of time that appliances are in the high-power 

mode by ensuring that the appliance is used in the lowest possible power mode whenever 

practical.55

 

55 International Energy Agency. 2001. THINGS THAT GO BLIP IN THE NIGHT Standby Power and How to Limit 

it. www.iea.org/textbase/nppdf/free/2000/blipinthenight01.pdf. 

79 
Water Heating and Distribution Systems 

At the 30% improvement level, energy use for heating hot water becomes a significant 

component of total energy use. Consequently, the following guidance has been developed for 

the design and installation of domestic hot water (DHW) systems: 

DHW Heater Sizing. The size of tank and first-hour draw pattern can have an impact on the 

overall energy consumption associated with hot water. Tank size is a function of first-hour 

rating, draw patterns, and incoming and outgoing water temperatures. The sizing method 

described in the next paragraph takes into account the nominal population of a house, the main 

supply water temperature, and the efficiency of the DHW heating equipment. 

Sizing Method for Tank Type DHW Heater. Use this method for determining the size of the 

tank-type domestic hot water heater (Figure 20). 

1. Establish the design population of the house by taking the number of bedrooms + 1 

2. Multiply this by the gallons/person for the climate zone where the house is located to get the 

first-hour rating for the water heater 

3. Using the first-hour rating from Step 2, select a DHW heater that meets or exceeds this rating 

4. For a tank-type gas heater, select a heater with an energy factor greater than 0.60. For a tanktype electric heater, select a heater that meets the current NAECA standard. 

Figure 20. Domestic hot water tank sizing for 135°F tank temperature only 

80 
Heater Selection. The efficiency target for fuel-fired tank-type gas DHW heaters is 0.60 EF or 

higher. With the tight house construction of the 30% improvement level, these 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 

gasses outdoors. If electricity is used for heating water, a high efficiency tank or tankless unit 

should be used. 

Tankless water heaters (about 0.84 EF) can provide significant advantages over the traditional 

storage-tank water heaters for a number of reasons: 

• Energy Savings: Tankless water heaters have a higher energy factor compared to tank water 

heaters and are, therefore, a more energy-efficient option. 

• Space savings: Tankless water heaters are dimensionally smaller and save space compared 

to storage tank water heater. This allows for installation in spaces with limited area or in 

locations closer to the point of use. 

• Longer life expectancy and favorable life cycle costs: The tankless water heater has a life 

expectancy of 15 to20 years compared to a typical 9 years for storage-tank water heaters. 

When the replacement of a tank water heater is combined with the lower operating costs, the 

life-cycle costs of a tankless water heater is generally lower than a tank-type water heater. 

Some builders have chosen to install multiple gas-fired tankless units, which may require 

upsizing of the main gas service when coupled with other gas end-uses in the house (furnace, 

cooking appliances, dryer, etc.). This could be a significant barrier to widespread adoption, 

especially in areas with low gas pressures. By installing multiple units, builders are safeguarding 

against a call from homeowners that there isn’t enough hot water, but may be overcompensating 

because of lack of experience with the tankless gas-fired technology. 

Tank-type heaters offer the best efficiency with relatively steady, continuous-use patterns. If 

electricity is the energy source for water heating, additional improvements to other areas of the 

house will likely be needed to achieve the 30% savings levels because there is very little room 

for improvement in electric water-heating efficiency compared to the possible efficiency gains 

using gas-fired technologies. 

Stand-alone electric heat pump water heaters offer better efficiency than electric resistance 

heaters, but they are complex, costly, and still evolving as a standard commercial product. They 

provide the best efficiency when their cold-air discharge can be used to augment home air 

conditions, which can be a benefit in cooling-dominated climates. Conversely, they can 

contribute to an additional heating load during the winter. Optimizing these relationships along 

with this performance variation as a result of supply water temperature and load pattern is quite 

challenging. Primarily because of the early state of technology deployment and reliability, 

stand-alone heat-pump water heaters are not considered a practical choice at the 30% level. 

Should these units improve in reliability and volume manufacturing brings costs down, then they 

would be worth considering as part of the overall package. 

If a ground-source heat pump is chosen for space heating and cooling, it is possible to use it to 

generate hot water, either through a desuperheater on the basic water-to-air heat pump or by 

using a water-to-water system where the heat pump can generate heated or chilled water to be 

used for space conditioning and domestic hot water. These systems can be effective, but the 

81 
pricing varies dramatically by region and can be more complex than a traditional gas furnace 

with DX air-conditioning systems. In an area where no natural gas is available, this system is an 

option in all climate zones; however, it requires a skilled and experienced installer base and 

favorable pricing. 

While not necessarily required to achieve the 30% whole-house energy-savings target, there are a 

number of reliable solar DHW heaters in the market. They represent a range of operating 

philosophies: 

• Storage/non-storage 

• Freeze-protected/drain-back 

• Passive thermosystem/pumped cycle, etc. 

With good design, these solar systems can all be effective sources of hot water, particularly in 

sunny climates. What most degrades the performance of solar DHW systems are the details of 

design, construction, operation, and maintenance. Research has found that simple set of 

characteristics such as long pipe run from the collector plate combined with a short, infrequent 

usage pattern can render the solar contributions nearly negligible. Primarily because of their high 

cost, solar DHW systems are not considered practical at the 30% improvement level. 

Hot-Water Distribution Systems. The hot-water distribution system plays a surprisingly 

important role in the total energy efficiency of the DHW system. Thermal losses from the hotwater distribution piping system while water is flowing and the losses associated with “stranded” 

hot water as it cools down once faucets are turned off can amount to a very substantial portion of 

total hot water energy use. Thus, guidance on the configuration of the system, its insulation, and 

patterns of use can help reduce the piping system component of DHW energy use. 

Basic guidance on the layout of DHW piping suggests that the DHW source and major use points 

should be as close to each other as practical. A good example of this would be the location of 

the DHW heater in a closet adjacent to the kitchen and a laundry that are back-to-back. Short 

lines will minimize “stranded” losses, which can be considered detrimental during the cooling 

season. Tankless water heaters can be located immediately adjacent to high-use clusters, such as 

a pair of bathrooms in a remote wing or a second floor, to reduce piping heat losses. 

All DHW supply piping should be insulated with standard R-4 pipe insulation. It is readily 

available, inexpensive, and effective. This includes any hot-water lines located in concrete slabs 

or underground. Increasing tank insulation to a minimum of R-12 by adding a tank insulation 

wrap can also reduce energy consumption. 

Research has also shown that “parallel-piped” or “homerun” plumbing systems using PEX 

piping and a central manifold can reduce energy consumption compared to traditional copper 

“tree and branch” plumbing systems.56

To avoid the waste of water as one “waits for the hot water to arrive” and to provide 

instantaneous hot water, there is growing use of recirculation systems that continuously circulate 

hot water through the entire system. This continuous circulation of hot water results in great heat 

 

56 NAHB Research Center, Inc. Performance Comparison of Residential Hot Water Systems. Upper Marlboro, MD: 

NAHB Research Center, Inc., November 2002. 

82 
loss from the piping system, even if insulated, and is strongly discouraged in an energy-efficient 

house of any type. 

If a recirculation system must be installed, a push-button-activated on-demand recirculator is by 

far the best recirculation system option. While all well-designed recirculation systems reduce 

water waste relative to conventional main-and-branch plumbing design, the push-buttonactivated on-demand recirculation system minimizes the length of time the recirculation loop is 

kept hot. 

The on-demand circulator is primarily useful for use points that are a long way from the DHW 

source and represent a substantial water waste while waiting for the hot water to “arrive.” 

Combination Systems – Space and Water Heating 

For the purposes of this discussion, combination systems refer to any system that uses a single 

combustion appliance to provide both the space heating and the domestic hot water needs for the 

home. Combinations systems used by Building America teams have included 

• a gas-fired boiler serving hydronic baseboard units for space heating and an indirect storage 

tank for domestic hot water, 

• a gas-fired storage water heater for domestic hot water and serving space-heating loads via a 

hydronic coil in a central fan-coil unit, 

• a gas-fired tankless water heater for domestic hot water and serving space-heating loads via a 

hydronic coil in a central fan-coil unit, 

• a combination boiler that provides hot water for space heating, as well as domestic hot water 

via a separate heat exchanger, and 

• a gas-fired boiler with one or more hydronic coils for space heating and an indirect-storage 

tank for domestic hot water. 

The primary advantages of these systems are 

• the reduced cost and complexity of only having to vent one combustion appliance. This can 

be significant when direct-vent equipment is desired. 

• the improved energy efficiency for serving the domestic hot-water load. Indirect tanks have 

significantly lower losses than gas-fired storage tanks with flues. Removing the tank losses 

entirely with a tankless, on-demand system provides further improvements. 

An important factor for success in all of these systems is that the plumbing and HVAC 

contractors must coordinate and cooperate. Builders are often concerned about who is ultimately 

responsible for the system. Ideally, one contractor would be responsible for the entire system, 

but if a forced-air system is used, this situation is unlikely. 

Systems that use a storage water heater to serve both loads should only be considered in homes 

with modest space-heating loads―25 kBtu/hr or less at design. In the Cold Climate region, this 

probably confines their consideration to multifamily homes. Also, careful design and attention 

83 
to detail is necessary for proper operation of these systems.57 Thermo-siphoning during summer 

air-conditioning operation has been observed in several installations. 

Common boilers for space heating will typically have lower AFUE ratings than commonly 

available condensing furnaces. Thus, the magnitude of space-heating loads versus domestic 

water-heating loads is important to the overall whole-house energy savings. Condensing boilers 

are available from a limited number of manufacturers, but they are expensive and their 

performance has not been thoroughly evaluated by the Building America teams. 

Onsite Power Systems 

A number of on-site power-production systems are currently available for Building America 

projects, and others are in the research stage. Most have been used in Building America projects. 

These systems include the following: 

• Photovoltaics 

• Engine generator/combo systems 

• Fuel cells. 

The 30% improvement level can be achieved most cost effectively through the improvement of 

the envelope, heating, cooling, domestic hot-water systems, and possibly the application of some 

lighting and appliance improvements. On-site power systems are very costly and are not 

recommended as a strategy to achieve the 30% savings level. 

Cost Analysis 

Life-Cycle Cost Analysis 

From a purely economic point of view, building energy optimization involves finding the global 

optimum that balances investments in efficiency versus utility-bill savings. However, there are 

sometimes non-economic reasons for targeting a particular level of energy savings. Given a 

particular energy-savings target, economic optimization can be used to determine the optimal 

design (lowest cost) to achieve the energy-savings goal. The analysis presented below targets 

30%-39% whole-house energy savings with respect to the Benchmark by using the BEopt 

analysis method to investigate cost tradeoffs associated with various residential energy efficiency 

and renewable-energy technology options. 

Building Characteristics Considered in this Study. For the Prototype building, a two-story 

3000-ft2 and a single-story 1500-ft2 residential building was used for this study with the front of 

the buildings facing east. Although complex floor-plan geometries can be analyzed, a simple 

square floor plan was implemented for the purposes of the current analysis. The buildings are 

modeled with a full basement. Both buildings were assumed to have three bedrooms and two 

bathrooms. The building has 1-ft eaves. Window area is assumed to be 18% of floor area with 

50% of the window area facing west, 25% of the window area facing east, 12.5% of the window 

area facing north, and 12.5% of the window area facing south. The non-uniform window 

distribution was utilized in order to represent a possible “worst case” window distribution from 

 

57 Combo Space/Water Heating Systems – “Duo Diligence,” Building Science Corporation. 

84 
the available window distribution options currently included in the BEopt analysis method. The 

energy options considered in the study include space-conditioning systems (up to SEER 18 and 

92.5% AFUE in the current study), envelope systems, hot-water systems, lighting systems, major 

appliances, and residential PV. The buildings use natural gas for the following end uses: 

cooking, space and water heating, and clothes drying. For the Chicago example cases, the 

uninsulated basement case option was not included in the analysis. Air-conditioner capacities 

less than 1.5 tons were not considered, nor were furnace capacities less than 50kBtu/hr. SEER10 air-conditioning equipment was included in this analysis for discussion purposes; however, 

after January 1, 2006, Federal minimum equipment efficiencies will mandate the use of SEER13 air conditioners. No options that would potentially reduce miscellaneous electric loads other 

than major appliances were included in the study. 

Occupancy/Operational Assumptions. Occupancy and operational assumptions are as defined 

in the Benchmark and include time-of-day profiles for occupancy, appliance and plug loads, 

lighting, domestic hot-water use, ventilation, and thermostat settings. 

Base-Case Building. Results are calculated relative to the Benchmark. The Benchmark defines 

baseline features, including wall, ceiling, and foundation insulation levels and framing factors; 

window areas, U-values, and solar heat gain factors; interior shading; overhangs; air-infiltration 

rates; duct characteristics; and heating, cooling, and domestic hot water system efficiencies. 

Cost Assumptions. Each option has an assumed first cost and lifetime (Appendix B). Costs are 

retail and include national average estimated costs for hardware, installation labor, overhead, and 

profit. Some are input as unit costs that are then multiplied by a category constant (e.g., ceiling 

insulation costs are input per square foot and multiplied by ceiling area by BEopt). Some inputs 

are energy-option specific (e.g., cost of solar water heating systems). Inputs can also be based on 

total costs (e.g., cost of wall constructions with different insulation values) because BEopt will 

calculate the differences between option costs. 

Construction costs (wall insulation, ceiling insulation, foundation insulation, etc.) are typically 

based on R.S. Means58 cost estimates. Window and HVAC costs are based on quotes from 

manufacturers’ distributors. Appliance costs are based on manufacturers’ suggested retail prices. 

Building construction options (wall insulation, ceiling insulation, foundation insulation, 

windows, etc.) are assumed to have 30-year lifetimes. Equipment and appliance options 

typically have 10- or 15-year lifetimes. Lifetimes for lighting options (incandescent and compact 

fluorescent lamps) are modeled based on cumulative hours of use. 

Utility costs are assumed to escalate at the rate of inflation (i.e., to be constant in real terms). 

The mortgage interest rate is 5% above the rate of inflation. The onsite power option used for 

this study was a residential PV system with an installed cost of $7.50 per peak Watt DC, 

including present value of future operation and maintenance costs. This cost is assumed to be 

independent of PV system size. Additional costs associated with mounting large PV arrays were 

not considered. For Chicago, natural gas is assumed to cost $0.8044/Therm, and the cost of 

electricity was modeled as $0.0771kWh. 

 

58 Residential Cost Data – 18th Annual Edition. 1999. Kingston, MA: R.S. Means, Company, Inc. 

85 
86 

 

Simulation Limitations. Some benefits not considered by the BEopt analysis method will have 

an influence on the real-world design of a home, such as reduction in warrantee and liability 

exposure, increased customer satisfaction, and higher quality construction practices. The BEopt 

analysis method does not consider concerns with regard to IAQ, mold, and combustion safety. 

In a real world design, these factors may lead the designer, engineer, builder, or architect to use 

equipment or construction practices that increase first cost without reducing utility bills in order 

to provide better indoor air quality, combustion safety, occupant comfort or other design 

considerations that have high value to the builder or potential homebuyer. There are also some 

side effects that the simulations are not equipped to deal with, such as the costs of change in a 

builder's organization necessary to implement energy-efficient design approaches, the costs of 

moving a trade base to a different place, or termination of long-term relationships with a trade 

because the trade would not adopt energy-efficient practices. There is currently no methodology 

available to account for these effects in the simulation. Further development of a methodology 

to account for these effects and collection of appropriate data to inform the simulation would be 

necessary if there is interest in considering these effects. 

The BEopt analysis method is relatively new to the Building America program, the case studies 

included in the Building America Systems Research Results section were not initially simulated 

with BEopt nor was BEopt used to guide the design process of the case study homes included in 

the section of this report entitled Building America Systems Research Results. The case studies 

are the result of years of field experience and design work done by Building America teams. 

Currently, this analysis method is being used for general programmatic guidance in an effort to 

understand at what cost and performance specifications efficiency and renewable technologies 

begin to look attractive when compared to other efficiency and renewable technologies. In its 

current form, the BEopt analysis method is useful for programmatic studies in terms of weighing 

the merits of certain efficiency and renewable technologies versus standard construction 

practices or other technologies using national average cost data, retail cost data, or projected 

costs for emerging technologies; however, cost of these technologies may be very different on a 

production or custom-builder scale. The results shown here should not be taken as representative 

of all builders in this climate region. 

As an example of what building efficiency options would lead to a combination of options that 

would achieve 30-39% whole-house energy efficiency relative to the Benchmark an optimization 

was performed with the Chicago TMY259 weather file. Figure 21 shows the 35% whole-house 

energy efficiency point that falls on the cost-optimal curve for Chicago. 

59 Typical Meteorological Year weather data, http://rredc.nrel.gov/solar/old_data/nsrdb/tmy2/ 
Figure 21. The 35% point for a single-story Chicago example case

87 
88 

Based on the costs assumed as shown in Appendix B, and within the limitations of the analysis 

method and the previously mentioned assumptions, the options selected in Figure 22 would 

represent a possible least-cost combination for 35% whole-house energy savings for a singlestory residence in Chicago. Because costs may vary significantly across the Cold Climate 

region, from builder to builder, and over time, the above is only an example that may not reflect 

the actual least-cost set of options that would apply to a specific home, builder, and location. 

At the other end of the building energy performance range considered here, 39% whole-house 

energy savings, the total monthly cost is slightly higher than the 35% example. Figure 22 shows 

an example combination that meets 39% whole-house energy savings compared to the 35% 

combination. 
Figure 22.60 Comparison of 39% point to the 35% point, one-story Chicago example 

89 

60 Note that cost show in this figure are incremental relative to the 35% energy savings point (shown in magenta) 
90 

The comparison of the 35% combination (represented in magenta) to the 39% combination (blue 

only) shown in Figure 23 demonstrates that by utilizing additional exterior wall insulation, 

basement wall insulation and a higher performance Low-e glazing, the 39% combination is 

slightly less expensive in terms of total cost per month than the 35% single-story example. 

There are some cost savings associated with downsizing of cooling equipment as a result of 

envelope improvements. 

Figure 23 and Figure 24 look at the same energy-performance levels for the two-story case. 

The comparison of the 35% combination (represented in magenta) to the 39% combination (blue 

only) shown in Figure 24 demonstrates that by investing in additional basement wall insulation, 

an ENERGY STAR dishwasher and a SEER-15 air conditioner results in the 39% point being 

only slightly more expensive in terms of total cost per month for the two-story example. Table 7 

shows detailed features for the 35% and 39% example cases. A more comprehensive table of 

examples that include energy end-use results and comparison to the Benchmark is shown in 

Appendix B for single- and two-story cases. 
Figure 23. The 35% point for the two-story Chicago example case 

91 
Figure 24.61 Comparison of the 39% point to the 35% point, two-story Chicago example 

61 Note that costs shown are incremental relative to the 35% energy savings point. 

92 
93 

Table 7. Comparison of Single- and Two-Story Cases 

CATEGORY 35% EXAMPLE 39% EXAMPLE 

Number of Floors One Story Two Stories One Story Two StoWalls R-19, 2x6, 24 in. oc R-19, 2x6, 24 in. oc R-19, 2x6, 24 in. oc + 2-in. polyiso (R- 14) R-19, 2Ceiling R-40 FG R-40 FG R-40 FG R-40 FG Thermal Mass 5/8-in. Ceiling Drywall 1⁄2-in. Ceiling Drywall 1⁄2-in. Ceiling Drywall 1⁄2-in. CInfiltration SLA = 0.0003 SLA = 0.0003 SLA = 0.0003 SLA = 0Basement 4-ft R-5 Exterior Insulation 4-ft R-5 Exterior Insulation 8-ft R-10 Exterior Insulation 8-ft R-1Glass Type 

Two-pane, Low-e, U = 0.32, SHGC = 0.64 Center of Glass, 

insulated spacer, Vinyl frame 

Two-pane, Low-e, U = 0.29, SHGC = 0.29 Center of Glass, 

insulated spacer, Vinyl frame 

Two-pane, Low-e, U = 0.29, SHGC = 0.29 Center of Glass, insulated spacer, 

Vinyl frame 

Two-pa= 0.29 C

spacer, 

Window Area per Wall 

270 ft2, 12.5% N&S, 50% W, 

5% E 

540 ft2, 12.5% N&S, 50% W, 25% E 270 ft2, 12.5% N&S, 50% W, 25% E 540 ft2, 

E 

Refrigerator Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr StandaCooking Range 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 TherDishwasher 

ENERGY STAR, 384 kWh, eight place setting capacity, 82.2 kWh/yr 

machine energy, 3.76 gal/day DHW 

Standard, 462 kWh, eight place setting capacity, 131.6 kWh/yr 

machine energy, 5.39 gal/day DHW 

ENERGY STAR, 384 kWh, eight place setting capacity, 82.2 kWh/yr machine 

energy, 3.76 gal/day DHW 

ENERGplace se

machinDHW 

Clothes Dryer 

Gas - 5.7 ft3, 2.75 EF, 70.1 

kWh/yr, 31.8 therms/yr 

Gas - 5.7 ft3, 2.75 EF, 70.1 

kWh/yr, 31.8 therms/yr 

Gas - 5.7 ft3, 2.75 EF, 70.1kWh/yr, 

31.8 therms/yr 

Gas - 5

31.8 the

Clothes Washer 

Standard, 3.15 ft3, 533 kWh/yr, 

1.16 MEF, 65.6 kWh/yr machine energy, 4.63 gal/day DHW 

Standard, 3.15 ft3, 533 kWh/yr, 

1.16 MEF, 65.6 kWh/yr machine energy, 4.63 gal/day DHW 

Standard, 3.15 ft3, 533 kWh/yr, 1.16 

MEF, 65.6 kWh/yr machine energy, 4.63 gal/day DHW 

Standa

1.16 MEenergy, 

Lighting 100% CFL, 439 kWh/yr hard- wired, 331 Plug in 100% CFL, 707 kWh/yr hard- wired, 571 Plug in 100% CFL, 439 kWh/yr hard-wired, 331 Plug in 100% C

571 Plu

Air Conditioner 

SEER 10, 2 Tons, 0.365 W/CFM AH Fan 

SEER 10, 3 Tons, 0.365 W/CFM AH Fan 

SEER 10, 1.5 Tons, 0.365W/CFM AH Fan 

SEER 1AH Fan 

Furnace 92.5% AFUE, 50 kBtu/hr 92.5% AFUE, 75 kBtu/hr 92.5% AFUE, 50 kBtu/hr 92.5% 

Ducts 

Inside Conditioned Space, SA leakage = 1%, OA leakage = 

0.23% of fan flow 

Inside Conditioned Space, SA leakage = 1%, OA leakage = 

0.23% of fan flow 

Inside Conditioned Space, SA leakage = 1%, OA leakage = 0.23% of fan flow 

Inside Cleakage 0.23% 

Water Heater Gas Tankless, 0.84 EF Gas Tankless, 0.84 EF Gas Tankless, 0.84 EF Gas Ta
Table 7 shows very small differences in the options selected between the one- and two-story 

cases for the energy-savings levels and combinations selected. The differences between one- and 

two-story examples at the 35% and 39% energy-savings level are limited to air-conditioner 

SEER, glazing types, dishwashers, and exterior-wall insulation levels. Within the limitations of 

the economic model included in the BEopt analysis method, the above example cases would 

represent a reduction in total monthly cost (mortgage cost – utility cost) when compared to the 

neutral cost line shown in Figure 6. 

First-Cost Impacts 

For all of the 30%-39% energy-savings level example cases shown here and in Appendix B the 

first costs are increased. Many builders are reluctant to design first-cost increases into their 

standard products. To many potential homebuyers, the first cost of a home can make or break a 

home sale. In order to address first-cost concerns associated with energy-efficient home designs, 

some builders have implemented guaranteed energy-bill programs that may influence some 

potential homebuyers such that they would be more willing to absorb the additional first cost into 

a 30-year mortgage knowing that their monthly cash flow will ultimately be reduced when the 

utility bill is considered: 

Builders who guarantee their homes are willing to tell buyers how much energy 

the home should use, and they guarantee these levels will not be exceeded. These 

guarantees are backed up with payments if limits are exceeded. Builders can work 

with insulation companies or other partners to offer guarantees or caps on their 

home’s energy costs, or they may develop their own programs. Some cover room 

comfort by guaranteeing that the temperature at the thermostat will not vary by 

more than 3 degrees at the center of any room served by that thermostat. A 

Building America team helped to develop these programs. Information on three of 

these programs can be found at 

o Environments for Living – www.eflhome.com/index.jsp

o Engineered for Life – www.us-gf.com/engineered.asp

o The Energy Use and Comfort Guarantee –

www.artistichomessw.com/guarantee.htm.

62

In some cases, homebuyers may be eligible for energy-efficient mortgages that allow potential 

home buyers to qualify for larger loans in order to compensate for additional first costs 

associated with energy-efficient options that are designed into a home. The case study of the 

Foothills at Wingfield, Reno, Nevada, shows an example of a guaranteed energy-bill program. 

The following features for energy-efficient loans are taken from Fannie Mae, the 

nation’s largest source of funding for mortgages. You can learn more about 

Fannie Mae at www.fanniemae.com. 

o Energy-efficient mortgages (EEM) are available for both purchase and refinance 

in conjunction with most Fannie Mae first-mortgage products, including 

conventional fixed-rate and adjustable-rate mortgages. 

 

62 Building America Best Practices Volume 3, Builders and Buyers Handbook for Improving New Home Efficiency, 

Comfort and Durability in the Cold and Very Cold Climates, October 2004, NREL/TP-550-36960, Page HOM-5. 

94 
o Monthly savings resulting from energy efficiency can be used to qualify 

borrowers for a larger mortgage. This means consumers can buy more home in 

the form of energy efficiency or other upgrades. 

o The EEM can be used with many Fannie Mae mortgage products. The guidelines 

of the selected Fannie Mae mortgage apply, with the EEM allowing for the 

projected energy savings to provide an adjustment to the loan-to-value and 

qualifying ratios that favor the borrower.63

Table 8 shows the first costs associated with the 35% and 39% two-story example cases. 

At a 7% mortgage interest rate, an additional $7,794 first cost associated with energy efficiency 

measures only represents an additional $52 per month for a 30-year loan term. It is important to 

note that the cost data used in this analysis may not be representative of actual builder or 

consumer costs in the Chicago area or other Cold Climate areas. The actual first cost for energy 

efficiency options for a particular builder and potential homeowner in the Cold Climate area may 

vary substantially from Table 8. Variations in costs would affect the outcome of the analysis 

method. Other examples of actual first costs associated with the construction of homes that meet 

the 30% - 39% savings criteria are found in the case studies section of this report and also in the 

section entitled First Costs, Cost Tradeoffs, and Owner Annualized PITI + Energy. 

Table 8. Incremental First-Cost for Two-Story Chicago Case 

Category Chicago, Two-story 

Incremental First-Cost 

 35% Example 

Incremental First-Cost 

39% Example 

Walls $247.00 $1,959.00 

Ceiling $270.00 $270.00 

Infiltration $1,630.00 $978.00 

Basement/ Slab $0.00 $694.00 

Window Type $1,501.00 $1,501.00 

Dishwasher $0.00 $60.00 

Lighting $376.00 376.00 

Air Conditioner -$460.00 $299.00 

Furnace $75.00 $75.00 

Ducts $960.00 $960.00 

Water Heater $622.00 $622.00 

Total $5,221.00 $7,794.00 

 

63 Building America Best Practices, Volume 3: Builders and Buyers Handbook for Improving New Home 

Efficiency, Comfort, and Durability in the Cold and Very Cold Climates, October 2004, NREL/TP-550-36960, Page 

HOM-4. 

95 
96 

Key Cost Tradeoffs 

The analysis for a single- and two-story home in the Chicago climate shows the main trends that 

result in a home that saves 30%-39% whole-house energy relative to the Benchmark. These 

trends are improved exterior-wall constructions, basement wall insulation, ceiling insulation, 

high-performance glazing, air-sealing measures to reduce infiltration, ducts in conditioned space, 

condensing furnaces, tankless gas water heaters; a number of the selected points used elevated 

levels of compact fluorescent lighting. The results indicate that the main driver for energy and 

cost savings in the Chicago climate are heating-load reduction strategies (high levels of 

insulation) coupled with high efficiency furnaces. While most of these measures add to first 

cost, the total monthly cash flow is actually reduced in terms of a 30-year mortgage when utility 

bills are considered. In some cases, envelope improvements cause a significant cooling-load 

reduction that can reduce the cost of the air-conditioning unit. Envelope measures, such as 

improved exterior wall constructions, basement wall insulation, ceiling insulation, highperformance glazing, air-sealing measures to reduce infiltration, and ducts in conditioned space 

make it possible to reduce heating and cooling loads such that investment in high efficiency 

reduced-capacity mechanical equipment is possible. The interaction between improving the 

building envelope and forced-air duct system to reduce the required capacity of mechanical 

equipment is the primary cost tradeoff for Cold Climates, as shown in the case studies and 

supported by the results from the BEopt analysis method. The case studies at Selkirk Twin 

Homes, Grand Forks, North Dakota, and Foothills at Wingfield, Reno, Nevada, show detailed 

examples of cost tradeoffs for energy-performance options 

Research Results and Conclusions 

Through the use of systems engineering and operations research, the Building America program 

has shown that homes that save 30% whole-house source energy in Cold Climates can be built 

on a cost-neutral basis by production builders. Table 9A shows a summary for energy-related 

features for the case studies included in the following section of this report and examples of 

results from use of the BEopt analysis method for Cold Climates. While the specific 

combinations of technologies used in the case studies or shown in BEopt results may not be costoptimal solutions for all areas and housing types covered by the Cold Climate, the key features 

of the approaches demonstrated in each of these examples can be adapted as needed to provide 

homes that save 30% whole-house energy savings. 

It should be also noted that the BEopt analysis method is subject to the limitations as described 

in the Cost Analysis – Life-cycle Cost Analysis section of this report. The case studies are the 

result of 3 years of field experience and design work done by Building America’s research 

teams. 
Table 9A. Summary of Energy Features for Case Studies and BEopt Results 

Case Studies BE

Category 

Eastern Dakota 

Housing Alliance, 

Grand Forks, 

North Dakota 

Foothills at 

Wingfield Reno, 

Nevada, Plans 1-4 

CDC of Utah, Magna, 

Utah

Claretian Associates,

Chicago, Illinois 

Kacin Homes, 

Pittsburgh, 

Pennsylvania 

35% Point Neighbor 

Floor Area (ft2) 1230 living / 600 unfinished Not Described 1540/1635 2592 1815 1500 1500 

Number of Floors 2 Not Described 2 2 2 1 1 

Number of 

Bedrooms Not Described Not Described 3/4 3 3 3 3 

Number of 

Bathrooms Not Described Not Described 3 Not Described 3 2 2 

Walls 

2x6, R-19 or 2x4, 

R-15 + 2-in. foam 

for ~ R24 

2x6, R-23 blown 

in cellulose + 1-in. 

R-4 EPS stucco 

2x6, 24 in. oc, 

R-23 blown-in 

fiberglass 

SIP, 6.5-in. R-24.7 R-5 sheathing, 2x4 16 in. oc, R-15 batt R-19, 2x6, 24 in. oc R-19, 2x6, 2

oc 

Ceiling R-49 unvented attic R-38 blown in 

fiberglass 

R-40 blown in 

fiberglass SIP, 10.25-in. R-42.5 R38 R-40 FG R-30 FG 

Thermal Mass Not Described Not Described Not Described Not Described Not Described 5/8-in. Ceiling 

Drywall 

1⁄2-in. Ceili

Drywall 

Infiltration 2.4 ACH50 2.5 in.2 per 100 ft2 of envelope 0.21 ACHann = unit 1, 0.22 ACHann = unit 2, 0.18 ACHann = unit 3 300-350 CFM50 0.27 ACHann SLA = 0.0003 SLA = 0.00

Basement/Slab/ 

Crawl space 

Basement = R-22 

forms 

Slab, R-10, 2-in. 

XPS slab-edge 

insulation 

Basement, 2-in. 

Polyisocyanurate,

R-13, 1⁄2-height 

interior insulation 

Basement, interior 4-

in. Rigid EPS 

Crawl space - 

unvented, R-3, rigid 

fiberglass, exterior; 

R-10 fiberglass, interior 

4-ft, R-5, Exterior 

Insulation 

4-ft, R-5

Exterior 

Insulatio

Glass Type Double-Pane, HighPerformance Vinyl, Low-E2, U = 0.35, SHGC = 0.33 Double-pane, low-e vinyl, U = 0.35, SHGC = 0.30 Low-e Vinyl U = 0.30, SHGC = 0.45 Wood-framed, double-glazed, U = 0.33, SHGC = 0.31 Two-pane, Low-e, U = 0.32, SHGC = 0.64 Center of Glass, insulated spacer, Vinyl frame Two-pane

Low-e, U = 0

SHGC = 0

Center of Gl

insulated spa

Vinyl fram

Window Area per 

Wall Not Described Not Described Not Described Not Described Not Described 

270 ft2, 

12.5% N&S, 

50% W, 25% E 

270 ft2, 

12.5% N&

50% W, 25% 

97 
Table 9A. Summary of Energy Features for Case Studies and BEopt Results (continued) 

Case Studies BEopt resu

Category 

Eastern Dakota Housing 

Alliance, Grand Forks, North Dakota 

Foothills at Wingfield, 

Reno, Nevada Plans 1-4 

CDC of Utah, Magna, Utah

Claretian Associates - 

Chicago, Illinois 

Kacin Homes - Pittsburgh, 

Pennsylvania 

35% Point Neighbor 5 

Refrigerator ENERGY STAR Best electric Not Described Not Described Not Described Standard, 671 kWh/yr Standard, 671 kWh/yr St

Cooking Range Not Described Best electric Not Described Not Described Not Described 45 Therms/yr 45 Therms/yr Dishwasher ENERGY STAR Best electric ENERGY STAR Not Described Not Described 

ENERGY STAR, 

384 kWh, eight 

place setting 

capacity, 

82.2 kWh/yr 

machine energy, 

3.76 gal/day DHW 

ENERGY STAR, 

384 kWh, eight place 

setting capacity, 

82.2 kWh/yr machine 

energy, 

3.76 gal/day DHW 

S

e

5

Clothes Dryer Not Described Best electric Not Described Not Described Not Described 

Gas - 5.7 ft3, 2.75 

EF, 70.1 kWh/yr, 

31.8 therms/yr 

Gas - 5.7 ft3, 2.75 EF, 

70.1 kWh/yr, 31.8 

therms/yr 

Ga

7

Clothes Washer ENERGY STAR Best electric Not Described Not Described Not Described 

Standard, 3.15 ft3, 

533 kWh/yr, 

1.16 MEF, 65.6 

kWh/yr machine 

energy, 

4.63 gal/day DHW 

Standard, 3.15 ft3, 

533 kWh/yr, 

1.16 MEF, 

65.6k Wh/yr machine 

energy, 

4.63 gal/day DHW 

S

4

Lighting 85% Fluorescent Not Described 70% CFL Many 

fluorescent 69% fluorescent 

100% CFL, 

439 kWh/yr 

Hardwired, 

331 Plug in 

100% CFL, 

439 kWh/yr 

Hardwired, 

331 Plug in 

Cooling Not Described SEER12 

OAsys indirect/direct evaporative cooler - 

unit 1/Freus water cooled condenser - unit 2/SEER12 - unit 3

SEER10 SEER13, 2.5 tons 

SEER 10, 2 Tons, 

0.365 W/CFM AH 

Fan 

SEER 14, 2 Tons, 

0.383 W/CFM AH Fan

S

0.3

98
99

Table 9A. Summary of Energy Features for Case Studies and BEopt Results (continued) 

Case Studies BEopt resu

Category 

Eastern Dakota 

Housing 

Alliance, Grand 

Forks, North 

Dakota 

Foothills at 

Wingfield, Reno, 

Nevada Plans 1-

4 

CDC of Utah, Magna, 

Utah

Claretian 

Associates - 

Chicago, 

Illinois 

Kacin Homes - 

Pittsburgh, 

Pennsylvania 

35% Point Neighbor 5 

Heating 92% AFUE 92% AFUE 

96% AFUE furnace 

direct-vent, ECM 

motor, two-stage gas

92.5% AFUE 

93% AFUE, 

direct-vent 60,000

Btu/h 

92.5% AFUE, 50 

kBtu/hr 92.5% AFUE, 50 kBtu/

Ducts Not Described 

Inside 

conditioned 

space, 

R4.2, less than 

5% leakage to 

outside 

Mastic Sealed, 

76 CFM @ 25 Pa - 

unit 1; 

59 CFM @ 25 Pa; 

unit 2 total to outside

Inside 

conditioned 

space 

Inside conditioned 

space, sheetmetal w/ UL181 

mastic, 30 CFM 

total leakage to 

outside 

Inside Conditioned 

Space, 

SA leakage = 1%, 

OA leakage = 0.23% of 

fan flow 

Inside Conditioned Spa

SA leakage = 1%, 

OA leakage = 0.23% of 

flow 

Water Heater Tankless 0.83 EF 0.62 EF 50 gallon gas water heater in garage 50 Gallon, 0.61 EF Power Vented 50-gallon 0.58 EF sealed combustion Tankless EF = 0.82, HW recirculation system Gas Tankless, 0.84 EF Gas Tankless, 0.84 E

On-site Power 

system None None None 1.2-kW grid tied None None None 
100 

Table 9B summarizes the source of the energy savings by end use. Figure 25 shows the location 

of the case studies presented in this report. Locations are indicated with stars. 

Table 9B. Summary of Source Energy Savings by End-use as a 

Percentage of Total Energy Use for the Cold Climate Case Studies

Percent Source Energy Savings 

End Use 

Eastern Dakota 

Housing 

Alliance: Grand 

Forks, North 

Dakota, Phase 2 

Foothills at 

Wingfield: Reno, 

Nevada Plans 1

through 4 

CDC of Utah: 

Magna, Utah 

Claretian 

Associates: 

Chicago, Illinois 

Kacin Homes: 

Pittsburgh, 

Pennsylvania 

Space Heating 58% 52/55/57/58% 53% 63% 53% 

Space Cooling 27% 46/50/48/54% 68% 0% 43% 

DHW 38% 28% 16% 7% 54% 

Lighting 40% 0% 49% 57% 37% 

Appliances + MEL 8% 3% 3% 5% 5% 

Total Energy Use 38% 33/35/35/37% 32% 36% 38% 

Number of Homes 12 165 3 26 117 
Figure 25. Location of 30% Cold-Climate case studies 

101 
House Case Studies 

Development: Selkirk Circle Twin Homes 

Builder: Applegren Construction 

Location: Grand Forks, North Dakota 

Fueled by Crises 

In 1997, a flood in Grand Forks, North Dakota, destroyed or damaged two-thirds of the houses in 

this town of 49,000. The average value of the homes lost in the flood was $72,000, which 

resulted in a shortage of affordable housing. In addition, severe winters in 2000 and 2001 

coupled with rising natural gas prices sent utility bills through the roof for low-income families. 

These crises galvanized the not-for-profit Eastern Dakota Housing Alliance (EDHA) to team 

with other non-profit organizations, cities, counties, and for-profit developers to build more 

affordable housing in eastern North Dakota. EDHA’s clients consisted of households earning 

below 80% of the area median income. Many of EDHA’s home buyers earn less than $30,000 

per year. Lisa Rotvold, the Director of EDHA and an architect, explained it in this way: 

We became interested in teaming with Building America because of the severe 

weather here. We needed a way to make heating and cooling more affordable. In 

the winter months, we have severe weather months with temperatures below 

minus 20 degrees. In the summer, we have temperatures in the 90s with high 

humidity. We get both extremes. In the last few years, we have seen significant 

jumps in the utility costs for natural gas. Our low-income families do not have the 

money to pay the heating and cooling bills, so we needed to build houses that use 

less energy. This was our motivation. 

In March 2003, EDHA completed its first of four housing phases working to Building America 

standards. Each of the four planned phases includes four twin-home (duplex) units. Each twostory home within the duplex unit has 1,230 ft2

 of living space with a 600- ft2 unfinished 

basement. The living space includes three bedrooms, 1.5 bathrooms, and a detached double-car 

garage (Figure 26 and Figure 27).

Figure 26. Phase-1 and Phase-2 Twin Home design 

102 
Figure 27. Twin home unit energy 

efficient affordable homes 

 “A great thing I appreciate about Building America is that they test the houses upon completion 

for energy efficiency and give them ENERGY STAR and Building America certification,” said 

Rotvold. 

Testing and certification is performed by Building America’s Industrialized Housing Partnership. 

HERS scores on four Phase I units completed in March 2003 were between 88 and 90 with 

whole-house savings of 25% to 30% against the Benchmark. Four Phase II units completed in 

January 2004 had an average HERS of 92.5 and whole-house savings of 39%. The higher 

efficiency in Phase II comes from the addition of a whole-house tankless gas water heater and 

R10 sheathing on exterior walls. Lower HERS scores (88.3 – 89.5) on the Phase III units was 

primarily a result of electric resistance water heating and slightly higher duct and envelope 

leakage. All units have ventilation air brought to the air-handler return plenum with 10 of 12 

units utilizing heat recovery ventilators (HRVs). Rotvold said: 

Our goal is that every house we build in this neighborhood will be built following 

Building America principles. In this process, the value that Building America has 

provided is the technical assistance and the systems approach to design. For 

example, we could have simply increased the insulation or done some other 

piecemeal things to improve energy efficiency, because we didn’t understand how 

to look at all of the systems of a house and how they can impact energy usage. 

Building America provided us with a lot of technical assistance. They guided us 

through the process. We stressed that we wanted practical solutions. They ran 

estimates to determine the financial payback of the energy efficiency measures we 

were considering. These estimates proved to be invaluable because we were 

getting lots of pressure to consider innovative methods (like geothermal heating 

from groundwater). However, the energy analysis Building America ran proved 

that these methods would not provide a payback for our small houses, so we 

learned that innovative is not always effective. 

We wanted a common sense package of features. 

103
Innovations 

As with all Building America homes, these features begin with super-tight construction, which 

during the testing phase must demonstrate an air-sealed interior. Because of this tight design, 

builders incorporated the Lifebreath mechanical ventilation system for bringing clean air into the 

house and expelling stale air (Table 10). 

According to Rotvold: “We are building healthy houses. When you build a house so tight, you 

must consider systems for getting clean air in—which in the winter can be very cold. Therefore, 

we installed ‘air-to-air’ heat exchangers.” An air-to-air heat exchanger uses outgoing warm air to 

heat the incoming air stream. 

Another energy-efficient feature is increased insulation. The Phase I homes have 2x6 walls at 16 

in. on center (o.c.) insulated with R-19 batt insulation (Figure 28). The vented attic is insulated 

to R-49. 

Table 10. Builder Profile: Applegren Construction 

Price Range: 

From $115,000 to $120,000 

Key Features: 

• High-efficiency GMC natural gas furnace 

• Lifebreath air-to-air heat exchanger 

• R-15 spray-on fiberglass insulation 

• Tight construction envelope 

• R-22 insulated basement forms 

• R-49 attic insulation 

• High efficiency tankless gas water heater 

• Efficient lighting system 

• Programmable thermostat 

• ENERGY STAR appliances 

Where: 

 Grand Forks, North Dakota 

Founded: 

 1978 

Employees: 

 10 employees 

Development: 

 Selkirk Circle 

Size: 

 Space for 22 units in the development 

Square footage: 

Duplex with each unit 1,230 ft2

 with a 600-ft2

unfinished basement and either an attached or 

detached garage. 

• Double-pane high-performance windows 

104
Figure 28. The houses feature 1-1/2-in. XPS foam at corners 

The wall exterior is OSB sheathing, building paper, and vinyl siding. All electrical boxes on the 

exterior walls are sealed to prevent air seepage. The basement can be upgraded in the future to a 

living space with two windows at grade level provided for each of two future bedrooms.

The homes are heated with a 92%-efficient gas furnace. The thermostat is programmable to 

allow specific temperatures to be set for specific times of the day. 

Each home is sold with ENERGY STAR appliances, including a horizontal-axis clothes washer, 

dryer, dish washer, and refrigerator. 

Finally, considerable effort focused on replacing incandescent bulbs and fixtures with fluorescent 

lighting. EDHA increased the use of fluorescents from a typical 10% of the home’s lighting to 

85% by installing linear fluorescent fixtures and providing compact fluorescent (CFL) bulbs for 

appropriate standard fixtures. 

Rotvold explains that they are learning and applying what they learn with each phase. In 

addition, she notes that more energy-efficient products and options are available on the market 

now than when they started with Phase 1 a few years ago. For example, in Phase 2, they 

switched to a tankless gas water heater. Tankless means that the hot water is not stored; instead, 

it is heated on-demand by powerful gas burners. Because the heater is not heating the whole 

tank, just the water needed at that moment, it uses less energy. Another change was to switch 

from 2x6 walls with R-19 batt insulation to 2x4 walls with blown-in fiberglass to R-15. Two in. 

of extruded polystyrene (R-10) is installed except in areas where 1⁄2-in. OSB bracing is required. 

These corner-braced areas received 1-1/2 in. of insulated sheathing (R-7.5). This gave an overall 

R-value of approximately R-24. “The water heater made a very big difference,” said Rotvold. “It 

was a costly item but it has a good payback for us.” 

Comfort, Durability, and Health 

“We are really proud of these houses,” explained Rotvold. “The quality is so much higher than 

the market is producing. Also, anecdotally, I am hearing that the heating bills are much less in 

our homes.” The homes are sold for $115,000 to $120,000, which is the appraised value. Seven 

of the first eight buyers earn less than $30,000 per year. For the buyers, the North Dakota 

105
Housing Finance Agency’s Community Partners program provides a 1% to 2% interest rate buydown. The city provides up to $7,500 in down-payment assistance. The developer provides a 

subsidy of between $2,000 and $20,000. Finally, Rotvold relies on grant funding to help fund the 

energy efficiency upgrades. “Without the grants, we would be losing money doing the upgrades, 

partly because we are pricing affordably and not pushing the market to make these upgrades 

appraise,” said Rotvold. She believes in the quality of the homes and the value of the energyefficient features for their lower income buyers. 

The Bottom Line 

“This is a model project,” said Rotvold. “It is a tremendous cooperative effort. I would tell other 

companies who are considering Building America that if you can get in the door, do! Get the 

technical assistance they provide because it helps you to make good decisions. We didn’t do 

everything David [the Building America Technical Assistant from Florida Solar Energy Center] 

suggested because we had to balance dollars; however, David thinks from a systems approach, so 

we just didn’t increase insulation we made small improvements to many of the systems within 

the homes. Attention was provided to every little detail in relation to the whole.” 

Economics 

Excerpts from a 2004 ASHRAE publication provide an economic comparison of the Selkirk twin 

homes (Table 11) with a theoretical regional base case using DOE2 simulations. Energy 

measures from the Phase II units were evaluated progressively by adding one measure at a time 

to the base case in the order listed in Table 12 arrive at estimated savings numbers. Major 

construction components or equipment were added first, such as envelope measures and the gas 

furnace. ENERGY STAR appliances were added before the water heater upgrade to highlight 

their savings with respect to electrically heated water. 

One row in Table 12 shows the cumulative effect of all measures added to the base-case home. 

Estimated saving in this row includes the cumulative effect of all measures incorporated together 

in the DOE2 simulation. The heat recovery ventilator (HRV) is broken out from the other 

measures to provide a meaningful simple payback and first-year cash-flow figures for the other 

cumulative measures. The HRV is considered an essential component for the indoor air quality 

of these homes but comparing it to a base-case home without ventilation means no relative 

savings are attained, thus this measure is added in a separate row. With the exception of the HRV 

all measures show a positive cash flow on a 6%, 30-year fixed rate mortgage beginning in the 

first year. 

106
Table 11. Completed Selkirk Homes 

Phase 1 Phase 2 Phase 3 

Number of Homes 4 4 4 

Completion Date Mar-03 Jan-04 Aug-04 

HERS range 88 – 90 92.5 88 – 89.5 

Benchmark range 30% 38% TBD 

Table 12. Economic Assessment of Phase-2 Measures 

Energy Measure Annual 

Savings

Installed 

Cost 

Simple 

Payback 

First Year 

Cash Flow 

Upgrade walls to (R10 sheath + R15 FG batt) $72 $600 8.3 $31 

Reduce infiltration from 5.0 to 2.4 ACH50 $106 $325 3.1 $82 

Upgrade from 78% to 92% direct vent furnace $40 $600 15.0 -$1 

Switch to Programmable Thermostat $18 $130 7.2 $6 

Upgrade to ENERGY STAR appliancesa $60 $730 12.2 $12 

Electric tank to EF-0.83 tankless gas water 

heater 

$94 $1,250 13.3 $10 

Increase from 10% to 85% fluorescent lighting $31 $200 6.5 $18 

All Measures $421 $3,835 9.1 $158 

Heat recovery ventilation @75cfm, 33% RTF ($43)b $1,400 N/A -$134 

All Measures with HRV $378 $5,235 13.8 $24 

Notes: a

 ENERGY STAR appliances include refrigerator, dishwasher, and h-axis clothes washer 

b

 First-year cash flow based on 30-year fixed rate mortgage with interest rate of 6%, down payment 

of 5%, and discount rate of 5%. A general inflation rate of 3% per year was applied to the upgrade 

cost of measures replaced at end of lifetime. Final value of equipment is determined by linear 

depreciation over lifetime. Interest paid on mortgage is considered tax deductible using a tax rate of 

28%. Energy costs escalate at 3% per year. A property tax rate of 0.8% was applied to the energy 

upgrade cost and is inflated at 3% per year. 

107
The 2003 average local natural gas ($0.748/therm) and electric ($0.06/kWh) rates were obtained 

from the serving utility for these calculations. The economics, however, become difficult to 

quantify for both the furnace and tankless gas water heater upgrades in light of recent natural gas 

price fluctuations. In the 10 years before 2000, gas prices (Figure 29) were relatively stable with 

a slight rise in the summer months when heating demand is reduced. This trend was interrupted 

in the winter of 2000-2001 when prices remained high throughout the winter as shown in the bar 

chart. Such fluctuations would impact furnace upgrade savings, making the high efficiency unit 

look more favorable against a standard efficiency furnace. For the gas water heater, on the other 

hand, increasing gas prices would reduce its cost effectiveness relative to an electric model 

typically installed in this area. Historically, more stable electric costs in North Dakota were 26% 

below the national average of $0.0813/kWh in 2003 (EIA 2004). 

Source: U.S. Energy Information Administration (converted to $/therm from $/Mcf using estimated heat content of 

1,029 Btu/cubic foot) 

Figure 29. Average natural gas prices for North Dakota residences

108
Development: Magna, Utah 

Builder: Community Development Corporation of Utah 

Location: Magna, Utah 

The Community Development Corporation of Utah (CDCU) is a 501(c)3 non-profit organization 

established in 1991. Their mission is to help low-income families achieve homeownership and 

become stable partners in the community. People with disabilities, those living in substandard 

housing, those on public assistance who are seeking self-sufficiency, and people in danger of 

being homeless or institutionalized receive priority attention. 

To date, the CDCU has assisted more than 1,400 families in 97 Utah communities. In addition to 

keeping the first cost of the homes low, the CDCU recognizes the importance of reducing 

operating costs. For families to thrive, low-income homeowners must be able to operate and 

maintain their homes. 

Initially, the CDCU partnered with Building America under the Existing Residential Buildings 

Program. After successfully completing a low-income rehab project in January 2004, the CDCU 

was anxious to apply the lessons learned to new construction. The CDCU acquired three lots 

adjacent to the completed Magna rehab project. 

Three Building America prototype homes were built on the adjacent lots in Magna, Utah. These 

homes demonstrate the CDCU’s ongoing commitment to building safe, durable, and energyefficient housing. The CDCU is working to transform the small city of Magna and improve the 

quality of housing available to low-income families. The plans developed meet the needs of the 

future families, fit into the site and surrounding community, comply with local codes, and 

achieve high energy performance. 

109 
A site plan for the project is shown in Figures 34 through 37). The first- and second-floor plans 

of Unit #2 are shown on the following page. Also included is an overlay of the two floors. In 

the overlaid drawing, the alignment of bearing walls and location of mechanical chases can be 

identified. 

Figure 34. Magna site plan 

110
Figure 35. Unit #2 first-floor plan 

111
 

Master Bedroom 

M. Bath M. Clos 

NW Bedroom 

SE Bedroom 

SW Bedroom 

Figure 36. Unit #2 second-floor plan 

112
Figure 37. Magna first- and second-floor overlay 

113
Specifications for All Units 

Square Footage 1,540 ft2 and 1,635 ft2 with 770-ft2

 and 670-ft2 basements, 

respectively 

No. of Bedrooms Three and four bedrooms 

Foundation Walls 2-in. foil-faced polyisocyanurate insulation (R-13), half-height 

installation 

Exterior Walls 2x6 wood framing, 24 in. OC, advanced framing 

Wall Insulation R-23 blown-in fiberglass 

Vapor Retarder Poly-vapor barrier on the interior 

Floor System Space joist TE open-web trusses 

Rim/Band Joists Insulated with two-component spray-foam 

Floor over Garage R-19 batt insulation 

Windows Low-e, double-pane, vinyl frame (U = 0.35, SHGC = 0.30) 

Ceiling Insulation R-40 blown-in fiberglass 

Duct System Engineered duct system, sealed with mastic 

Transfer Grilles R.A.P. transfer grilles 

Space Heating Carrier infinity, 96% AFUE furnace, direct-vent, ECM motor, twostage gas 

Thermostat Programmable 

Water Heating Power-vented, A.O. Smith Powershot, 50 gallon, EF = 0.61 

Lighting 70% compact fluorescent 

Appliances ENERGY STAR dishwasher 

Ventilation Upgraded bath fan and Grasslin pin timer 

114
In addition to the above specifications, each unit features a different high performance cooling 

system: 

• Unit 1: OASys Indirect-Direct Evaporative Cooler (IDEC) integrated with a Dynamic 

Ceiling System 

• Unit 2: Freus Evaporative Condenser combined with oversized indoor evaporator coil to 

maximize sensible cooling capacity and the Energy Efficiency Rating 

• Unit 3: SEER 12 Condenser combined with oversized indoor evaporator coil to maximize 

sensible cooling capacity and the Energy Efficiency Rating (EER). 

Prototype Features 

The winning bid fell within the range of typical construction costs for past CDCU projects. 

Although these homes include high-performance envelopes and upgraded mechanical equipment, 

the bid was competitive with standard practice construction. A number of factors helped to keep 

the bid low, including: economies of scale for three homes, advanced framing drawings detailing 

the reduction in materials, minimized ductwork, and complete drawings and specifications. 

Foundation Insulation 

Two inches of foil-faced polyisocyanurate insulation (R-13) was installed on the interior upper 

half of the wall, which accounts for the greatest amount of heat loss (Figure 38). The rigid 

insulation board was adhered horizontally on the upper portion of the wall and using a quicksetting construction adhesive. The seams between each sheet were sealed with metal tape and 

the corners were caulked. Because the insulation is foil faced, it did not have to be covered to 

meet building code requirements. The insulation was installed tight to the floor trusses. This 

created a lip at the top of the foundation, which was useful when applying spray-foam insulation 

to the band joist. 

Figure 38. Foil-faced polyisocyanurate insulation 

115
Compact Duct System 

The HVAC system was coordinated with the advanced framing. The system was designed to 

minimize ductwork, to keep all ducts within the conditioned space, and to provide balanced 

supply and return airflows. Chases were provided for supply trunks and central returns, 

eliminating the need for ductwork in exterior walls. No panned ductwork was permitted, and the 

system was sealed with mastic to reduce duct leakage. Homes have central returns on the first 

and second floor and a separate return from the master suite. 

Space Cooling 

A unique feature of Unit #2 is the Freus evaporative condenser (Figure 39). As standard 

practice, the CDCU typically installs SEER 10 air conditioning systems in their homes. CARB 

researched equipment incentives available and found that Utah Power was offering $250 for the 

installation of SEER 12 equipment. Higher SEER equipment, such as the Freus unit, qualified 

for a $350 incentive. 

Figure 39. Freus evaporative condenser (left) and a 

cut-away sketch of the Freus unit (right) 

116
Figure 40. Nutone fan and Grasslin pin timer 

Mechanical Ventilation 

These homes were air-sealed to reduce infiltration, making mechanical ventilation extremely 

important. These homes feature an “exhaust-only” ventilation strategy. An upgraded low-sone, 

energy efficient bath fan rated for continuous duty was installed in the main bathroom of each 

home. To control the fans, a pin timer was installed in a nearby closet. A manual switch in the 

bathroom allows the occupants to use the fan for local exhaust, while the timer ensures adequate 

run time to provide ventilation for the home. These prototypes are capable of complying with the 

guidelines set forth by the American Society of Heating, Refrigerating and Air Conditioning 

Engineers (ASHRAE) in Standard 62.2, Ventilation and Acceptable Indoor Air Quality in Lowrise Residential Buildings. Figure 40 shows the Grasslin Timer (Model # KMA ST-1G) installed 

in a closet off the bathroom. 

Energy Modeling 

Using Energy Gauge USA 2.10 software, the energy performance of Unit #2 was modeled and 

compared to the “Building America Research Benchmark Definition version 3.1.” The energy 

modeling included in this report is based on the floor plan, specifications, and mechanical 

equipment installed in Unit #2. It also includes data obtained during the performance testing of 

the homes, such as infiltration and duct leakage rates. 

Based upon the actual specifications, the prototype will have an estimated 32% total energy 

reduction compared to the Benchmark and use 26% less than the CDCU’s standard practice. For 

further details, see Table 21. 

117
Table 21. Energy Consumption by End-Use and End-Use Source Energy and Savings 

118
Community-Scale Case Studies 

Development: New Homes for South Chicago, Illinois 

Builder: Claretian Associates, South Chicago Workforce 

Location: South Chicago, Illinois 

Introduction 

In South Chicago, Illinois, Claretian Associates, a non-profit community development 

organization, and South Chicago Workforce, a non-profit local builder, are in the process of 

building “New Homes for South Chicago III” (Figure 41): 26 efficient, affordable homes on 

empty lots in the South Chicago neighborhood. Energy efficiency, sustainability, and the health 

of the homes are the prime concerns of the developer and the builder. 

The Consortium for Advanced Residential Buildings (CARB) began working with Claretian 

Associates and South Chicago Workforce as part of DOE’s Zero Energy Homes program. The 

primary goals were to monitor the energy performance of the homes’ solar energy systems and to 

evaluate the performance of several ventilation systems in the first three homes. 

General Features and Specifications 

Each three-bedroom single-family home has 2,592 ft2 of living space, including the conditioned 

basement. The baseline specifications of these homes achieve the Building America 30%-40% 

total energy savings level. An additional 5% total energy savings is provided by site generated 

power, in the form of photovoltaic (PV) panels on the roof. 

Figure 41. Two of the “New Homes for South Chicago, Illinois 

119
Figure 42. SIPs installed in the first home 

Foundation 

Each home has a walk-out basement with poured concrete walls. The foundation walls were 

insulated on the interior with 4 in. of rigid expanded polystyrene (EPS) insulation. 

Walls and Roofs 

Structural insulated panels (SIPs) were used for all above-grade walls and roofs of the homes 

(Figure 42). Wall SIPs are 6.5 in. (R-24.7) and ceiling SIPs are 10.25 in. (R-42.5). Openwebbed floor trusses support the first and second floors, and rock-wool was blown into these 

rim-joist cavities (R-20 or higher). It is believed that these buildings are the first SIP homes 

allowed within the city of Chicago. The SIP envelopes, combined with meticulous air sealing, 

resulted in very tight envelopes. Blower door tests on the three homes that were monitored 

showed infiltration between 300 and 350 CFM50. 

Windows 

The selected ENERGY-STAR® windows are manufactured by Certainteed with low-emissivity 

glazing and vinyl frames. U-values are 0.30 Btu/ft2hr°F and solar heat gain coefficients are 0.45. 

Heating 

The homes are heated by condensing, sealed combustion furnaces (Armstrong, 92.5% AFUE). 

Sheet-metal duct systems distribute air throughout the homes. 

120
Figure 43. Sealed-combustion furnace and 

water heater in the first home. 

Water Heating 

To eliminate any chance of back-drafting in these very air-tight homes, all combustion 

appliances (with the exception of the kitchen ranges) are sealed combustion (Figure 43). The 

AO Smith “Sealed Shot” water heaters (50 gallon, EF 0.58) draw combustion air through a PVC 

vent and send exhaust directly out through the wall. 

Cooling 

When homeowners purchase the air-conditioning option, SEER-10 Armstrong air conditioners 

provide cooling. Though few homebuyers chose this option, energy analyses presented here 

assume that the air conditioning is installed. 

Ventilation 

Providing fresh air for occupants is a key component of the developer’s commitment to high 

Indoor Environmental Quality (IEQ) and healthy homes overall. South Chicago Workforce 

approached CARB with a proposal to evaluate several types of ventilation systems. In the spring 

of 2003, CARB completed the installation of monitoring systems in the first three homes. 

Starting in November 2003, CARB collected data for approximately 18 months. CARB 

monitored three different ventilation systems in the first three homes: 

• Energy recovery ventilation (ERV) 

• Air cycler (outdoor air duct to return plenum) 

• Exhaust only ventilation (timers on efficient bath exhaust fans) 

121
CARB monitored temperature, humidity, and CO2 levels at three points inside each house, plus 

one point outside the homes. CARB has begun to evaluate the energy and IEQ ramifications of 

each of the ventilation systems. 

Solar Electricity 

On the first 12 homes in the scattered development, South Chicago Workforce is installing 1.2-

kW PV systems. The Spire modules are mounted on the south-facing roofs of the homes. Sunny 

Boy inverters are located near the electrical panel in the basement. 

Lighting 

Most fixed lighting in the homes is fluorescent. Overhead fixtures in the kitchen, dining rooms, 

and bathrooms are fluorescent, and recessed cans all contain compact fluorescent lamps (CFLs). 

Energy Modeling and Benchmark Analysis 

Energy modeling – primarily using Energy Gauge USA – predicted a total energy savings of 

33% for these homes, compared to the Benchmark. The modeled savings rose to 38% when 

energy from the solar electric systems was factored in. Most of the savings was achieved by 

reducing the space-heating loads, by upgrading both the building envelope and the equipment 

efficiency. A review of the utility bills found that the expected heating energy use closely 

matched the actual use. 

Modeling predicted the following energy use: 

• Space heating: 424 therms/year 

• Cooling: 2017 kWh/year 

• Water heating: 218 therms/year 

• Lighting, appliances, and misc. electric loads: 6910 kWh/year. 

Lessons Learned 

In all homes using forced air for heating and cooling, CARB strongly recommends the use of air 

handlers with ECM-driven fans. Such air handlers generally consume nearly 200-250 Watts. 

Furnaces in this home, while very efficient in burning gas, consumed between 700 and 800 

Watts. This led to staggering electricity consumption, especially in the homes where central air 

handlers were used for fresh air ventilation. 

The HVAC contractor informed CARB that the incremental cost for more electrically efficient 

furnaces would be approximately $1,000. This was not possible with the project’s budget. But 

even when the furnaces provide heating alone (no cooling or ventilation), an efficient fan could 

save homeowners $75-$100 each year. An efficient air handler fan is absolutely essential when 

part of an efficient, whole-house ventilation system. 

122
Awards 

In part because of the efficiency and green features of these homes, the “New Homes for South 

Chicago” project received Chicago’s 2005 award for “Outstanding Non-Profit Neighborhood 

Real Estate Project.” More information on the award is available at: 

http://www.lisc-cnda.org/2005.php?recipient=claretian

123
Development: Foothills at Wingfield 

Builder: D.R. Horton 

Location: Reno, Nevada 

D.R. Horton has constructed a Building America development aimed at achieving overall energy 

savings of 30%. This builder is responsible for Sierra Valley Oaks, the 30% community of 2004. 

A total of 165 Building America homes will be constructed. The switch to a Cold Climate in 

Reno created new design issues to overcome (Figure 30). 

The homes are designed with high levels of insulation in the walls, using the R-23 Optima blown 

cellulose in 2x6 framing and with high-performance vinyl windows. The air handler and 

ductwork are located in conditioned space and outside ventilation is provided. 

This development is unique because it is the first DR Horton development in Reno, Nevada, with 

slab-edge insulation. Figure 31 is a picture of the detail for the insulation. 

Figure 30. From left to right, the Foothills at Wingfield Models, 

Plans 1, 2, 3, and 4 

124
 

 Figure 31. Slab-edge insulation detail 

This insulation should protect the slab from cold temperatures and will lower heating costs for 

the development. The exterior configuration with the monolithic pour was an economical 

strategy for DR Horton to insulate their slabs. The photos below show the sheet-metal protection 

for the finished product (Figure 32). 

Initially, there was some confusion with regards to the sequencing of the slab-edge construction. 

Concern was raised as to the vulnerability of the exposed XPS getting destroyed on-site before 

the pour. There is a possibility that a design may be implemented in future developments that 

has the XPS installed on top of the slab below a sub-floor to further simplify the construction 

process. 

 

Figure 32. Edge insulation properly protected with sheet metal 

125
Energy Analysis 

Energy consumption simulations were done for each of the floor plans to compare the total enduse energy-consumption reduction of the prototype characteristics to the Benchmark. The 

energy analyses were completed using EnergyGauge USA USRRPB v 2.42 modeling software. 

The prototype models were based on the design criteria in Table 13. 

Table 13. Foothills at Wingfield Building Characteristics 

Building 

envelope 

Ceiling R-38 Insulsafe 4 flat attic blown fiberglass

Walls R-23 Optima 16 o.c. 2X6 walls + 1-in. R-4 EPS Stucco 

Frame Floors R-30 Insulsafe 4 flat attic blown fiberglass

Foundation Slab, R-10 2-in. XPS on perimeter

Windows Milgard Classic Vinyl Spectrally Selective LoE2

Weighted Average U = ~0.35, SHGC = ~0.33

Infiltration 2.5 in.2 leakage area

per 100 ft2

 envelope

Mechanical 

systems 

Heat Sealed-combustion 92% AFUE gas 

furnace in conditioned space (closet)

Cooling 12 SEER split system in conditioned space

DHW 0.62 EF 50-gallon gas water heater in garage

Ducts R-4.2 flex runouts in dropped ceiling or in floor joists

Leakage none to outside (5% or less)

Ventilation Aprilaire VCS 8126 Supply-only system integrated with AHU 

33% Duty Cycle: 10 minutes on; 20 minutes off

60-80 CFM continuous average flow

Return Pathways Transfer grilles/jump ducts at bedrooms

126
Table 14. Foothills at Wingfield Source Energy-Use Summary 

Plan 

Number Annual Energy Use 

Annual 

Energy Use Percent Savings

Benchmark Prototype 

(10^6 Btu/y)r (10^6 Btu/yr) (%) 

1 222 148 33% 

2 246 159 35% 

3 274 177 35% 

4 329 207 37% 

The results of the source-energy consumption reduction analyses are highlighted in Table 14 

The average reduction was 35% over the Benchmark for the community. 

In addition, a series of parametric changes were applied to Plan 1 to see how each change from 

the Benchmark affected the overall source energy use reduction. 

The incremental parametric changes done in the simulation (EnergyGauge USA USRRPB v 

2.42) are described below. The abbreviation IOSEU is used to replace “incremental overall 

source energy use.” A negative value reflects an increase in energy use, and a positive value 

reflects a decrease (Figure 33 and Table 15). 

1. Benchmark: This step applies the Benchmark criteria to the floor plan used in the energy 

simulation. The energy consumption result is used as the basis for comparison for the rest of 

the parametric study. 

2. Envelope, Window Configuration Changes: The Benchmark basis the window areas of the 

house on 18% of the finish floor area. The distribution of the windows on each elevation is 

based on the same ratio of window distribution of the prototype house. This step resets the 

window configurations back to the prototype design. The resultant IOSEU was -0.2%. 

3. Overhangs: Overhangs and shading devices were added back into the design. There was a 

negligible energy savings from this step. The resultant IOSEU was 0.0%. 

4. Upgrade to Vinyl LoE windows U = 0.35, SHGC = 0.33: The windows used in the project 

were very similar in efficiency compared to the Benchmark. The resultant IOSEU was 0.1%. 

5. Increase ceiling insulation from R-36 to R-38: The increase in insulation level from the 

Benchmark was fairly small, resulting in a small energy savings. The resultant IOSEU was 

0.3%. 

127
6. Increase wall insulation from R-17.5 to R-27: Optima blown cellulose insulation, 2x6 wall 

construction, and exterior rigid insulation sheathing was used on this project. The resultant 

IOSEU was 3.6%. 

7. Air tightness: the Building America air tightness goal of 2.5 square inches per hundred 

square feet of envelope area was applied to the prototype model. The resultant IOSEU was 

6.8%. 

8. Ducts inside and duct leakage to 5%: All the ducts were moved into the interior of the 

conditioned space. This reduces the amount of duct leakage potential to the outside. The 

resultant IOSEU was 12.6%. 

9. 12 SEER air conditioner: The air-conditioner efficiency was upgraded from 10 SEER to 12 

SEER. Because of the relatively low air-conditioning load, only a small energy savings was 

realized. The resultant IOSEU was 0.3% 

10. 92% Furnace: The furnace was upgraded to a 92% sealed-combustion condensing furnace. 

The resultant IOSEU was 4.2%. 

11. 0.62 EF Water Heater: The water heater was upgraded to a 0.62 EF gas water heater 

located in the garage. The resultant IOSEU was 2.1%. 

12. Best Electric Appliances: High-efficiency appliances were used in the energy analysis. The 

resultant IOSEU was 2.4%. 

The total energy savings over the Benchmark was 32.3%. The results of the energy consumption 

analyses are highlighted Tables 16, 17, 18, and 19. 

Parametric Annual Loads Study

0

50

100

150

200

250

Benchmark

As-built base

Overhangs

Lo-E2 Windows

R-38 Roof

Walls R-17.5 to R-27

Air Seal

DuctsInside

12 SEER

92% Furnace

0.62 EF Water Heate

Energy Star Appliance

10^6 Btu/yea

Heating Cooling Hot Water Lighting Other

32.3%

Figure 33. Foothills at Wingfield effects of incremental improvement steps 

128
129

Table 15. Foothills at Wingfield Parametric Analysis Results 

Total Source Energy Savings 

(H/C/DHW/Lights/Appliances/Plug) 

 Description of change 

Over BA 

Benchmark1

Incremental 

Over 

Benchmark 

Annual 

Energy 

Cost 

Item 

Savings

Benchmark n/a n/a $1,291 n/a 

Envelope, window configuration 

changes -0.2% n/a $1,294 n/a 

Overhangs -0.2% 0.0% $1,293 ($2) 

Upgrade to vinyl LoE windows U = 

0.35, SHGC = 0.33 0.0% 0.1% $1,290 $3 

Increase ceiling insulation from R-36 

to R-38 0.3% 0.3% $1,285 $5 

Increase walls from R-17.5 to R-27 3.9% 3.6% $1,248 $37 

Air seal 10.7% 6.8% $1,180 $68 

Ducts inside and duct leakage to 5% 23.3% 12.6% $1,045 $135 

12 SEER 23.7% 0.3% $1,038 $7 

92% Furnace 27.9% 4.2% $999 $39 

0.62 EF Water Heater 30.0% 2.1% $980 $19 

Best electric appliances 32.3% 2.4% $948 $32 
Table 16. Foothills at Wingfield Plan 1 Building America Benchmark Performance Report 

Table 17. Foothills at Wingfield Plan 2 Building America Benchmark Performance Report 

Table 2. Summary of End-Use Source-Energy and Savings

Table 1. Summary of End-Use Site-Energy

Percent of End-

Benchmark Proto Proto saving

End-Use kWh therms kWh therms End-Use 106 BTU/yr 106 BTU/yr

Space Heating 858 1039 490 458 Space Heating 131 59 55% 

Space Cooling 928 0 462 0 Space Cooling 10 5 50% 

DHW 0 251 0 182 DHW 30 21 28% 

Lighting* 1934 1934 Lighting* 20 20 0% 

Appliances + Plug 4343 99 4178 99 Appliances + Plug 56 54 3% 

OA Ventilation** OA Ventilation** 0 0 0% 

Total Usage 8062 1390 7064 738.75 Total Usage 246 159 35% 

Site Generation 0000 Site Generation 0 0 

Net Energy Use 8062 1390 7064 738.75 Net Energy Use 246 159 35% 

Estimated Annual Source Energy

BA Benchmark BA Prototype

Source 

Annual Site Energy

Table 2. Summary of End-Use Source-Energy and Savings

Table 1. Summary of End-Use Site-Energy

Percent of En

Benchmark Proto Proto savin

End-Use kWh therms kWh therms End-Use 106 6 BTU/yr 10 BTU/yr

Space Heating 766 925 455 436 Space Heating 117 56 52% 

Space Cooling 789 0 425 0 Space Cooling 8 4 46% 

DHW 0 251 0 182 DHW 30 21 28% 

Lighting* 1716 1716 Lighting* 18 18 0% 

Appliances + Plug 3768 99 3598 99 Appliances + Plug 50 49 3% 

OA Ventilation** OA Ventilation** 0 0 0% 

Total Usage 7039 1275 6195 716 Total Usage 222 148

Site Generation 0000 Site Generation 0 0 

Net Energy Use 7039 1275 6195 716 Net Energy Use 222 148 33% 

Estimated Annual Source Energy

BA Benchmark BA Prototype

Sour

Annual Site Energy

33% 

130
131

Table 18. Foothills at Wingfield Plan 3 Building America Benchmark Performance Report 

Table 2. Summary of End-Use Source-Energy and Savings

Table 1. Summary of End-Use Site-Energy

Percent of End-

Benchmark Proto Proto saving

End-Use kWh therms kWh therms End-Use 106 BTU/yr 106 BTU/yr

Space Heating 911 1088 510 460 Space Heating 137 59 57% 

Space Cooling 1566 0 812 0 Space Cooling 16 8 48% 

DHW 0 279 0 201 DHW 33 24 28% 

Lighting* 2219 2219 Lighting* 23 23 0% 

Appliances + Plug 5164 105 4975 105 Appliances + Plug 65 63 3% 

OA Ventilation** OA Ventilation** 0 0 0% 

Total Usage 9860 1472 8516 765.5 Total Usage 274 177

Site Generation 0000 Site Generation 0 0 

Net Energy Use 9860 1472 8516 765.5 Net Energy Use 274 177 35% 

Estimated Annual Source Energy

BA Benchmark BA Prototype

Source 

Annual Site Energy

35% 

Table 19. Foothills at Wingfield Plan 4 Building America Benchmark Performance Report 

Table 2. Summary of End-Use Source-Energy and Savings

Table 1. Summary of End-Use Site-Energy

Percent of End-

Benchmark Proto Proto saving

End-Use kWh therms kWh therms End-Use 106 BTU/yr 106 BTU/yr

Space Heating 1121 1339 616 550 Space Heating 169 71 58% Space Cooling 1997 0 911 0 Space Cooling 20 9 54% 

DHW 0 312 0 220 DHW 37 26 29% 

Lighting* 2589 2589 Lighting* 27 27 0% 

Appliances + Plug 6204 111 6003 111 Appliances + Plug 77 75 3% 

OA Ventilation** OA Ventilation** 0 0 0% 

Total Usage 11911 1762 10119 880.5 Total Usage 329 207

Site Generation 0000 Site Generation 0 0 

Net Energy Use 11911 1762 10119 880.5 Net Energy Use 329 207 37% 

Estimated Annual Source Energy

BA Benchmark BA Prototype

Source 

Annual Site Energy

37% 

*Lighting end-use includes both interior and exterior lighting **In EGUSA there are currently no hooks to disaggregate OA Ventilation
Table 20 shows the energy bill guarantee for the various floor plans. 

Table 20. Energy Bill Guarantee Summary for Foothills at Wingfield Models 

Plan Name 

Energy 

Star 

Annual 

Cost 

Monthly 

Cost 

MMBtu 

Heating

MMBtu 

Cooling Heating Cooling 

Plan 1 89.2 $491 $41 41.3 4.0 413 therms 1172 kWh 

Plan 2 89.4 $542 $45 46.6 4.0 466 therms 1172 kWh 

Plan 3 90.0 $597 $50 49.7 5.0 497 therms 1465 kWh 

Plan 3 Bed 6 89.7 $676 $56 54.7 6.2 547 therms 1817 kWh 

Plan 4 89.9 $682 $57 57.1 5.6 571 therms 1641 kWh 

Plan 4 Bed 6 89.7 $684 $57 56.3 5.9 563 therms 1729 kWh 

132 
Development: Summerset at Frick Park 

Builder: A. Richard Kacin Inc. 

Location: Pittsburgh, Pennsylvania 

Founded: 1960 

Employees: 30 

Size: Three bedrooms, three bathrooms 

Square Footage: 1,815 

Price Range: $310,000 - $360,000 

As a builder in the Summerset at Frick Park community in Pittsburgh, Pennsylvania, Kacin Inc. 

has benefited from learning how to build energy-efficient, durable, and comfortable homes. 

Summerset’s performance standards require the homes to achieve the Environmental Protection 

Agency (EPA) ENERGY STAR® level of energy efficiency and to meet quality-control 

objectives related to house durability, occupant comfort, and occupant health and safety. To 

manage the learning curve involved, Kacin has worked with Building America team member 

IBACOS since 2001 to understand the standards and to become proficient at implementing the 

innovative construction practices necessary to achieve the performance goals set forth in the 

standards. As a result, all of Kacin’s homes in the community’s first phase of construction meet 

the standard. 

Demand for the first 52 homes to be built was so strong that a lottery was held in which all the 

homes were sold within 1 hour and 15 minutes. For the second-phase lottery, more than 400 

buyers signed up for a chance to buy one of 65 homes. In addition to strong sales, Kacin has built 

a reputation of building high-performance homes, which gives them an edge in the competitive 

Pittsburgh marketplace. 

Kacin Inc. didn’t want to rest on their laurels, though. In the second phase of construction at 

Summerset, Kacin was interested in researching what greater levels of energy efficiency could be 

achieved at a cost-effective level. Kacin and IBACOS chose to build a pilot home to research 

cost-effective energy-efficient construction. The pilot home is a two-story building, with a twocar attached garage in the rear and a porch on the front. The house is built on a crawl space 

foundation and has 1,815 ft2 of living space. It has three bedrooms (one on the first floor), three 

bathrooms, 10-ft first-floor ceilings, and 9-foot second-floor ceilings. 

133
Figure 44. The front of the Kacin Construction pilot home faces southeast. Fiber-cement 

siding covers the exterior walls of the house not pictured. The attached garage is at the 

rear. 

Innovations 

The pilot home (Figure 44) was built to achieve a minimum of 40% savings in total energy using 

three primary system strategies: improve the thermal performance of the building enclosure; use 

high performance equipment to handle space heating, domestic hot water, and mechanical 

ventilation; and install high efficiency lighting and appliances . 

To achieve these strategies, this pilot home featured several advanced systems that Kacin 

Construction had seldom or never before implemented in the field. These included high-density 

fiber-glass insulation within exterior walls; practices to enhance building-enclosure airtightness 

even further; a high efficiency tankless hot water heater system; energy efficient lighting; and a 

balanced heat-recovery mechanical-ventilation system. In addition, Kacin was already familiar 

with many energy efficiency practices and technologies, including the following: 

• Building an unvented and conditioned crawl space with foundation walls insulated on the 

inside with R-10 fiber glass insulation with a perforated facing and R-3 semi-rigid fiberglass 

insulation board on the exterior face (to grade) (Figure 45). 

• Increasing building airtightness through draft-stopping and careful air sealing around 

penetrations 

• Installing R-5 insulating sheathing on exterior walls to improve wall airtightness, thermal 

performance, and durability 

• Using high efficiency heating and cooling equipment (Figure 46) 

• Increasing the performance of the air-distribution system. 

134
The Bottom Line 

Kacin Inc. has been committed to building energy-efficient, high-performance homes because 

they realize the value to customers and to their business. They chose to partner with the Building 

America Program initially to meet Summerset’s performance standards, but didn’t want to stop 

there. Through the construction of this pilot home, they’ve been able to research cost-effective 

measures to continue to build high-quality homes. By following the specifications for this pilot 

home, a homeowner may realize $387 or 22% in energy savings over other homes in Summerset. 

With respect to the Benchmark, energy savings are 38% and energy cost savings are $915. 

Figure 45. Once the HVAC subcontractor recognized the need to condition the 

crawl space, a register in the main trunk line was put in. This register was sealed 

up because it had the potential to divert too much air to the crawl space,, and a 

ducted register was installed in a more central location in the crawl space. 

135
Figure 46. Over-cabinet (fluorescent) and under-cabinet (halogen) lighting 

was used at the Kacin Construction project. Cove lighting, consisting of 

strip fluorescent lamps and recessed downlights with CFLs, were used in 

the adjacent dining room. 

Key Features 

• Unvented, conditioned crawl space. The crawl space (block) walls were insulated to-grade on 

the exterior with R-3 semi-rigid fiber glass insulation. On the inside R-10 fiber glass 

insulation batts with a perforated-vinyl facing cover the full height of the wall 

• R-38 attic insulation 

• Exterior walls consist of 1 in. (R-5) extruded polystyrene insulating sheathing with joints 

taped; 2x4 framing at 16 in. centers; R-15 kraft-faced fiber glass insulation batts in cavities; 

and drywall finish. Band joists are insulated with R-15 unfaced fiber glass insulation batts in 

cavities. 

• Long-term durability of the wall system was enhanced with a continuous drainage plane to 

shed water, which was created by taping the joints of the insulating sheathing and using 

flexible-flashing membrane around window and door rough openings. 

• To improve building airtightness, a great deal of emphasis was placed on draft-stopping large 

holes to ensure air-barrier continuity. In particular, draft-stopping was conducted at exterior 

136
137

wall locations where there was normally no drywall, such as behind tubs and at the fireplace. 

The numerous penetrations through the enclosure were sealed as well, particularly those 

connected to the attic and the crawl space. 

• Windows are wood-framed, double-glazed, argon-filled units (U = 0.33, SHGC = 0.31). 

• The high efficiency mechanical equipment consists of a 93% AFUE, direct-vent natural gas 

furnace with 60,000 Btu/h input and a 13 SEER (nominal) condensing unit. The cooling 

system uses Carrier’s Puron minimal ozone depleting refrigerant and has a 2.5-ton capacity. 

• A direct-vent gas tankless (EF = 0.82) hot water system was used. A hot-water recirculation 

system was installed to reduce time waiting for hot water. 

• The entire air-distribution system is fully ducted and within conditioned space. The furnace is 

located horizontally in the conditioned crawl space. Ductwork serving the second floor 

travels through first-floor interior walls to floor and high wall register locations on the second 

floor. A fully ducted return system draws air from each floor and each bedroom. The 

basement is fully conditioned. Ductwork was sheet metal and sealed with UL 181-approved 

water-based mastic sealant. 

• The results from the final duct-tightness test are 450 cfm total system leakage. The ductwork 

associated with ERV was included to permit testing. Of the 450 cfm total duct leakage, 30 

cfm of the leakage was to the outside. The total amount of air leakage exceeded the target 

value of 100 cfm, but the air leakage to the outside target of 30 cfm was met. 

• The pilot home has an airtightness value of 3.8 ACH at 50 Pa, which is approximately 

equivalent to an average annual natural infiltration rate of 0.27 ACH. The airflow induced by 

the blower door at 50 Pa was 1555 cfm. 

• A heat-recovery ventilator provides balanced mechanical ventilation. The system runs 

continuously, drawing outdoor air that is mixed with return air that draws from the second 

floor. The treated air then enters a main return air trunk before being distributed throughout 

the house. 

• A total of 69% of all hard-wired indoor lighting in the home is from fluorescent fixtures―

compact and linear. 

• Major appliances meeting ENERGY STAR® requirements were installed. 

Estimated savings for different advanced system design improvements to the pilot home with 

respect to the builder standard are noted in Tables 22 and 23. Energy costs are based on 

Duquesne Light Company average rate for electricity of $0.0876/kWh and Equitable Gas 

average rate for natural gas of $1.158/therm. 

By following the specifications for the pilot home a homeowner may realize $387 or 22% in 

energy savings. A discussion on the costs of different advanced system improvements follows. 
Table 22. Energy Simulation Results: Summary of Predicted End-use Site Energy for the Kacin Constru

Annual Site Energy 

BA Benchmark Builder Standard 

Home

Pilot Home D

End-Use kWh Therms kWh Therms kWh TSpace Heating 843 1016 694 602 563 Space Cooling 1101 0 797 0 625 DHW 0 215 0 208 0 Lighting 1876 0 1876 0 1173 Appliances 1206 98 1206 98 1096 Subtotal 5026 1329 4572 908 3457 Plug Loads 3412 0 3412 0 3412 Total Usage 8438 1329 7984 908 6869 

138 
Estimated Source Energy Sav

Annual Source Energy Percent of End Use Perce

End-Use BA 

Benchmark 

(Mbtu) 

Builder 

Standard 

(Mbtu) 

Pilot Home

(Mbtu) 

BA 

Benchmark 

Builder 

Standard 

BA 

Benchmark

Space Heating 113 69 53 53% 23% 26% 

Space Cooling 12 9 7 43% 22% 2% 

DHW 22 21 10 54% 52% 5% 

Lighting 20 20 13 37% 37% 3% 

Appliances 23 23 22 5% 5% 1% 

Subtotal 190 142 104 45% 27% 38% 

Plug Loads 37 37 37 0% 0% 0% 

Total Usage 227 179 141 38% 21% 38% 

Table 23. Summary of Estimated End-use Source Energy for the Kacin Construction Project 

139
Appendix A: Passive Solar Design Considerations 

There are three primary passive design systems: direct gain, indirect gain, and sunrooms. 

Direct Gain. In direct gain (Figure A-1), the sun shines directly into the house through 

windows, skylights, and clerestories. Depending on the amount and orientation of glazing, 

thermal mass materials may be needed to be incorporated in walls and floors to absorb the solar 

radiation and re-release it during the evening. Direct gain can also utilize a strategy called “sun 

tempering” where glazing is favored on the south side, but limited so that additional thermal 

mass is not necessary to prevent overheating of south-facing rooms. 

Figure A-1. Direct Solar Gain 

Indirect Gain. Indirect gain (Figure A-2), also called thermal storage wall and Trombe Wall, 

consists of a thermal mass wall, with direct southern exposure. For example, a thermal storage 

wall could be a poured-in-place concrete wall or a concrete masonry block wall with the cores 

filled with concrete. One or more panes of glazing are located immediately on the outside of 

these mass walls. The outside surface of the mass wall is painted a dark color or coated with a 

selective surface, such as those used in active solar collectors. 

Figure A-2. Indirect Solar Gain 

Sunroom. Passive solar sunrooms (Figure A-3) can either be isolated or open to the rest of the 

home. Because of the large areas of glass, it is usually recommended that they include doors and 

windows that can be closed to isolate them from the rest of the house. In this configuration, the 

temperature in the sunroom can be permitted to go higher and lower than would be permitted 

within the home. 

140 
Figure A-3. Passive Solar Gain 

To optimize the solar design of the house, which includes size of aperture, glazing performance 

characteristics (U-value and SHGC), by orientation, inclusion of mass, and house configuration, 

it is recommended that detailed energy simulations be undertaken. In general, if passive solar 

design is to be implemented, the following issues should be addressed, in the following order of 

importance: 

• Site planning to allow for optimizing house orientation 

• Orienting the house to optimize solar gains for heating and limiting solar gains during the 

cooling season. Simply by orienting homes with longer sides with larger glazing areas facing 

north-south helps to minimize unwanted heat gain in summer and maximize beneficial solar 

heat gains in winter (Figure A-4). 

Builders seeking to optimize individual home and lot orientation can follow these guidelines. 

Figure A-4. The paths of the sun in winter and summer over a home with long sides 

facing north and south 

• Minimize East and West Glazing. Orienting homes so that the sides with the least glazing 

face east and west can significantly reduce cooling loads and reduce glare. Typically, 

afternoon sun shining in west windows is most important to minimize or to shade. 

• North-South Orientation. Having the longer sides of homes facing north-south is beneficial 

for reducing both heating and cooling loads. In Cold Climates, having more glazing face 

south with adequate shading can minimize cooling and heating loads significantly; however, 

141
this must be carefully designed to prevent overheating and comfort complaints. South 

windows can most easily be shaded with overhangs. 

• Architectural Design. Shape the architectural form and solar apertures of the houses to 

optimize passive solar heating, including appropriate mass to avoid localized overheating, 

and summertime shading to mitigate cooling loads. This is best done in conjunction with 

hourly energy and room-temperature modeling to assure energy savings and occupant 

comfort. Passive designs typically employ increased use of dense materials like concrete-slab 

floors with tile and increased thickness of drywall or interior brick or concrete walls that 

have high conductivity to heat and high heat capacities. The increased mass can be as simple 

as replacing carpeted floors with inexpensive tile floors in slab-on-grade construction. If 

mass materials are warmed by winter sun and cooled with night ventilation systems in 

summer, they can add to comfort and reduce use of and consumption by conventional heating 

and cooling systems. 

• Night Cooling: Locate openings to optimize airflow during temperate conditions and to 

facilitate “night flushing” of heat built up over the day during the relatively cooler evening 

hours. 

Passive design may have a significant impact on the architectural character of the house and may 

be viewed in a positive or negative manner by builders and homebuyers. Passive strategies may 

be pursued as a trade-off for other energy improvements; however, careful consideration of 

occupant comfort must be taken into account. Effective passive solar heat gain can be very 

beneficial during the heating season, but it is challenging to design well and requires proper 

linkage of aperture and thermal storage in order to be useful and to avoid discomfort. 

Overheating is a significant problem. Passive cooling, both by window shading and glass 

transmission characteristics, is very beneficial during the cooling season. Window shading can 

be very effective, but its proper design is critical, and the shading elements may have a strong 

visual impact on the exterior of the house. Thus, it is not a strategy that is thought to be 

universally appropriate at the 30% improvement level. For more information on passive design 

strategies, see the Passive Solar Industries Council’s passive solar design guidelines.64 

Architectural Shading Considerations. Shading, like orientation, is not required to achieve 

30% savings, particularly with low-SHGC glazing. However, studies have shown that shading 

can cut solar heat gain by anywhere from 10% to 50%. Blocking the sun's rays from striking 

glazing areas and heating up a home is much more efficient than using air conditioning to cool 

down an already overheated house. 

“Architectural shading” is simple, does not need any maintenance, and may reduce costs 

compared to sophisticated shading devices. Incorporating shading methods into the home during 

the design phase ensures that a home receives the most effective shading. For example, providing 

properly designed overhangs shading the south glass adequately can reduce the heat gain during 

the summers while allowing for heat gain during the winters. Shading the west glass can also 

minimize the unwanted heat gains. A wide range of shading options is available, including the 

following: 

 

64 Sustainable Building Industries Council. Passive Solar Design Strategies: Guidelines for Home Building.

Sustainable Building Industries Council Website: www.psic.org.

142
• Overhangs on South Sides. Extending the roofline a few feet can create shade for a home's 

south-facing windows. Because sun angles drop in the winter months, south-facing 

overhangs will let the warming sun into the home when it is needed. Because of low sun 

angles in summer mornings and afternoons, overhangs on the east or west have little to no 

affect. Shades for east- or west-facing windows must have some vertical dimension, such as 

awnings or shade screens. 

• Decks and Porches. Adding a covered deck or porch is an excellent way to shade a home 

and to add living space, too. Porches and covered decks should have enough of an overhang 

to shield the area from the high sun and still offer a view outside from the interior spaces. 

• Awnings. Awnings provide excellent shading for south-, east-, and west-facing windows; 

awnings will block as much as 65% of the summer sun's heat (77% on an east- or west-facing 

window), but they have the disadvantage of blocking the top half of the view from the 

window and reducing ventilation when windows are opened. Retractable canvas awnings can 

overcome this problem to some extent because they can be extended only when they are 

needed. This is especially helpful in winter months, when occupants want to let the sun in to 

warm their home. 

• Louvers. Exterior louvers are attractive because their adjustable slats control the level of 

sunlight entering the building and, depending on the design, can be manually adjusted from 

inside or outside. The slats can be vertical or horizontal. Louvers remain fixed and are 

attached to the exteriors of window frames. Careful attention to the louver angle can allow 

significant winter sun penetration whilst still excluding all sun in summer. 

• Exterior Shade Screens. Retractable shade screens are a good choice for windows that 

receive direct sunlight. They work much like an inside window shade, except that they are 

attached to the outside of the window. Most shade-screen manufacturers offer automatic 

controls for these products. The screens are installed at the top of the window and can be 

lowered during sunny days and retracted when not needed. Shade screens are generally 

custom-made. They are a good choice for a homeowner who wants to retrofit for energy 

efficiency but still wants to see out of a window that gets lots of sun throughout the day. The 

downside of shade screens is that they can darken the view when pulled down. 

Designing Shading Systems. The following design recommendations generally hold true for 

properly designed shading devices: 

• Use fixed overhangs on south-facing glass to control direct-beam solar radiation. Indirect 

(diffuse) radiation should be controlled by other measures, such as low-e glazing. 

• To the greatest extent possible, limit the amount of east and west glass because it is harder to 

shade than south glass. Consider the use of landscaping to shade east and west exposures, 

awnings, exterior shade screens, or interior highly reflective shades. 

• Do not worry about shading north-facing glass because it receives very little direct solar gain. 

• Shading effects daylighting; consider both simultaneously. For example, a light shelf 

bounces natural light deeply into a room through high windows while shading lower 

windows. 

143
144

• Do not expect interior shading devices such as Venetian blinds or vertical louvers to reduce 

cooling loads because the solar gain has already been admitted into the work space. 

However, these interior devices do offer glare control and can contribute to visual acuity and 

visual comfort. 

• An understanding of sun angles is critical to selecting shading devices. 

• Carefully consider the durability of shading devices. Over time, operable shading devices can 

require a considerable amount of maintenance and repair. 

• When relying on landscape elements for shading, be sure to consider the cost of landscape 

maintenance and upkeep on life-cycle cost. 

• Shading strategies that work well at one latitude, may be completely inappropriate for other 

sites at different latitudes. Be careful when applying shading ideas from one project to 

another. 
Appendix B: Detailed BEopt Analysis Results 

Table B.1. BEopt Option Results for Single-Story Case 

Category Benchmark 35% Point Neighbor 1 Neighbor 2 Neighbor 3 Neighbor 4 Neighbor 5 Next 

Optim

C

Walls 

U = 0.052, 23% FF 2x6, R-19 batt, 

R-6 sheathing 

R-19, 2x6,

24 in. oc 

R-19, 2x6, 

24 in. oc 

R-19, 2x6, 

24 in. oc 

R-19, 2x6, 

24 in. oc 

R-19, 2x6, 

24 in. oc 

R-19, 2x6,

24 in. oc 

R-1

24 

Ceiling U = 0.026, 11% FF, R-38.5 R40 FG R-50 FG R-30 FG R-30 FG R-30 FG R-30 FG R-4

Thermal Mass 

8 lbs/ft2 - furniture, 

standard light-frame construction 

5/8-in. Ceiling 

Drywall 

1⁄2-in. Ceiling 

Drywall 

1⁄2-in. Ceiling 

Drywall 

1⁄2-in. Ceiling 

Drywall 

1⁄2-in. Ceiling 

Drywall 

1⁄2-in. Ceiling 

Drywall 

1⁄2-in

Dr

Infiltration SLA = 0.00057 SLA = 0.0003 SLA = 0.0005 SLA = 0.0003 SLA = 0.0003 SLA = 0.0003 SLA = 0.0003 SLA = 

Basement Wall U = 0.095, R-10 

4-ft R-5 

Exterior 

Insulation 

8-ft R-10 Exterior 

Insulation 

4-ft R-5 Exterior 

Insulation 

4-ft R-5 Exterior 

Insulation 

4-ft R-5 Exterior 

Insulation 

4-ft R-5 

Exterior 

Insulation 

4-ft R-

Ins

145 
Table B.1. BEopt Option Results for Single-Story Case (continued) 

Category Benchmark 35% Point Neighbor 1 Neighbor 2 Neighbor 3 Neighbor 4 Neighbor 5 Next 

Optim

C

Glass Type U = 0.39, 

SHGC = 0.32 

Two-pane, 

Low-e, U = 0.32, 

SHGC = 0.64 

Center of Glass, 

insulated 

spacer, Vinyl 

frame 

Two-pane, Low-e,

U = 0.32, 

SHGC = 0.64 

Center of Glass, 

insulated spacer, 

Vinyl frame 

Two-pane, Low-e,

U = 0.29, 

SHGC = 0.29 

Center of Glass, 

insulated spacer, 

Vinyl frame 

Two-pane, Low-e,

U = 0.29, 

SHGC=0.29 

Center of Glass, 

insulated spacer, 

Vinyl frame 

Two-pane, Low-e,

U = 0.29, 

SHGC = 0.29 

Center of Glass, 

insulated spacer, 

Vinyl frame 

Two-pane, Low-e,

U = 0.32, 

SHGC = 0.64 

Center of Glass, 

insulated spacer, 

Vinyl frame 

Two-pa

U = 

SHG

Center 

insulate

Viny

Window Area per Wall 

270 ft2, Equal 

dist. On 4 

sides 

270 ft2, 

12.5% N&S, 

50% W, 25% E 

270 ft2, 

12.5% N&S, 

50% W, 25% E 

270 ft2, 

12.5% N&S, 

50% W, 25% E 

270 ft2, 

12.5% N&S, 

50% W, 25% E 

270 ft2, 

12.5% N&S, 

50% W, 25% E 

270 ft2, 

12.5% N&S, 

50% W, 25% E 

27

12.5

50% W

Refrigerator 669 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Stand

kW

Cooking Range 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 ThDishwasher 

206 kWh/yr, 

5 gal

DHW/day 

ENERGY 

STAR, 

384 kWh, eight 

place setting 

capacity, 

82.2 kWh/yr 

machine energy, 

3.76 gal/day 

DHW 

ENERGY STAR, 

384 kWh, eight 

place setting 

capacity, 

82.2 kWh/yr 

machine energy, 

3.76 gal/day DHW

Standard, 

462 kWh, eight 

place setting 

capacity, 

131.6 kWh/yr 

machine energy, 

5.39 gal/day DHW

ENERGY STAR, 

384 kWh, eight 

place setting 

capacity, 

82.2 kWh/yr 

machine energy, 

3.76 gal/day DHW

Standard, 462 

kWh, eight place 

setting capacity, 

131.6 kWh/yr 

machine energy, 

5.39 gal/day DHW

ENERGY STAR, 

384 kWh, eight 

place setting 

capacity, 

82.2 kWh/yr 

machine energy, 

3.76 gal/day DHW

ENERG

384 kW

place 

cap

82.2 

machin

3.76 ga

Clothes Dryer 

Gas - 71.6 

kWh/yr, 

31.3 

Therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 

57.8 kWh/yr, 

26.2 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Gas 

2.7

70.1 

31.8 t

146 
Table B1 BEopt Option Results for Single-Story Case (continued) 

Category Benchmark 

35% 

Point 

Neighbor 

1 

Neighbor 

2 

Neighbor 

3 

Neighbor 

4 

Neighbor 

5 

N

Clothes Washer 

105 kWh/yr, 15 

gal/day 

Standard, 

3.15 ft3, 533kWh/yr, 

1.16 MEF, 

65.6 kWh/yr machine 

energy, 

4.63 gal/day DHW 

Standard, 

3.15 ft3, 

533 kWh/yr, 

1.16 MEF, 

65.6 kWh/yr machine 

energy, 

4.63 gal/day DHW 

Standard, 

3.15 ft3, 

533 kWh/yr, 1.16 

MEF, 

65.6 kWh/yr machine 

energy, 

4.63 gal/day DHW 

Standard, 

3.15 ft3, 

533 kWh/yr, 1.16 

MEF, 

65.6 kWh/yr 

machine energy,

4.63 gal/day DHW 

ENERGY STAR, 

top loader, 

H-axis, 2.9 ft3, 273 

kWh/yr, 1.68 MEF, 

72.9 kWh/yr 

machine energy,

3.71 gal/day DHW

Standard, 3.15 ft3

,

533 kWh/yr, 1.16 

MEF, 65.6 kWh/yr 

machine energy,

4.63 gal/day DHW

St

53

ME

m

4.6

Lighting 

14% CFL, 1574 

kWh/yr Hardwired, 331 Plug 

in 

100% CFL, 

439 kWh/yr Hardwired, 331 Plug in 

100% CFL, 

439 kWh/yr Hardwired, 

331 Plug in 

100% CFL, 

439 kWh/yr Hardwired, 331 Plug in 

100% CFL, 

439 kWh/yr Hardwired, 

331 Plug in 

100% CFL, 

439 kWh/yr Hardwired, 

331 Plug in 

100% CFL, 

439 kWh/yr Hardwired, 

331 Plug in 

1

wi

Air Conditioner 

SEER 10, 0.55 

W/CFM AH Fan 

SEER 10, 

2 Tons,

0.365 W/CFM AH Fan 

SEER 10, 

2 Tons,

0.365 W/CFM AH 

Fan 

SEER 10, 

1.5 Tons, 

0.365 W/CFM AH Fan

SEER 10, 

1.5 Tons, 

0.365 W/CFM AH 

Fan 

SEER 10, 

1.5 Tons, 

0.365 W/CFM AH 

Fan 

SEER 14, 

2 Tons,

0.383W/CFM AH 

Fan 

0.

Furnace 78% AFUE 92.5% AFUE, 

50 kBtu/hr 

92.5% AFUE, 

50 kBtu/hr 

92.5% AFUE, 50 

kBtu/hr 

92.5% AFUE, 

50 kBtu/hr 

92.5% AFUE, 

50 kBtu/hr 

92.5% AFUE, 50 

kBtu/hr 

92

Ducts 

Basement, 5% 

AH fan flow 

leakage to the 

outside 

Inside Conditioned 

Space, 

SA leakage = 1%, 

OA leakage = 0.23% of

fan flow 

Inside Conditioned 

Space, 

SA leakage = 1%,

OA leakage = 0.23% 

of fan flow 

Inside Conditioned 

Space, 

SA leakage = 1%,

OA leakage = 0.23% 

of fan flow 

Inside Conditioned 

Space, 

SA leakage = 1%, 

OA leakage = 

0.23% of fan flow 

Inside Conditioned 

Space, 

SA leakage = 1%,

OA leakage = 

0.23% of fan flow 

Inside Conditioned 

Space, 

SA leakage = 1%,

OA leakage = 

0.23% of fan flow

Ins

SA 

0.

Water Heater 

Gas, 40 gal, 

0.54 EF, 

0.76 RE 

Gas Tankless, 

0.84 EF 

Gas Tankless, 0.84 

EF 

Gas Tankless, 0.84 

EF + 32 ft2 ICS 

Gas Tankless, 0.84

EF + 32 ft

Gas Tankless, 0.84 

EF 2 ICS 

Gas Tankless, 

0.84 EF 

G

147 
Table B.2. BEopt Energy and Savings Results for Single-Story Case 

Benchmark 

35% 

Point 

Neighbor

1 

Neighbor

2 

Neighbor 

3 

Neighbor

4 

Neighbor 

5 

Ne

O

Energy End Use (MBtu/yr) 

Miscellaneous (E) 39.85 38.24 38.24 38.74 38.24 38.68 38.23 

Lights (E) 16.13 6.34 6.34 6.34 6.34 6.34 6.34 

Heating Fan (E) 5.26 2.73 2.61 3.28 3.28 3.28 3.00 

Cooling Fan (E) 1.43 0.76 0.87 0.35 0.35 0.35 0.75 

Cooling (E) 6.14 5.52 6.17 2.44 2.44 2.44 3.74 

Heating (G) 87.50 47.10 45.20 55.50 55.50 55.50 49.00 

Hot Water (G) 23.69 15.32 15.32 10.37 10.05 14.42 15.32 

Miscellaneous (G) 9.79 8.10 8.10 8.10 8.10 7.47 8.10 

Total 189.79 124.10 122.85 125.12 124.29 128.46 124.47 

148 
Table B.2. BEopt Energy and Savings Results for Single-Story Case (continued) 

Benchmark 

35% 

Point 

Neighbor

1 

Neighbor

2 

Neighbor

3 

Neighbor

4 

Neighbor

5 

Next P

Optimiza

End Use Savings 

Miscellaneous (E) 4.0% 4.0% 2.8% 4.0% 2.9% 4.1% 4Lights (E) 60.7% 60.7% 60.7% 60.7% 60.7% 60.7% 60

Heating Fan (E) 48.1% 50.4% 37.7% 37.7% 37.7% 43.0% 47

Cooling Fan (E) 46.5% 39.2% 75.5% 75.5% 75.5% 47.5% 71

Cooling (E) 10.2% -0.5% 60.3% 60.3% 60.3% 39.2% 53

Heating (G) 46.2% 48.3% 36.6% 36.6% 36.6% 44.0% 46

Hot Water (G) 35.4% 35.4% 56.2% 57.6% 39.2% 35.4% 35

Miscellaneous (G) 17.2% 17.2% 17.2% 17.2% 23.7% 17.2% 17

Total Energy Savings 34.6% 35.3% 34.1% 34.5% 32.3% 34.4% 36

149 
Table B.3. BEopt Option Results for Two-Story Case 

Category Benchmark 35% Point Neighbor 1 Neighbor 2 Neighbor 3 Neighbor 4 Neighbor 5 Nex

Opt

Walls 

U = 0.052, 23% FF 

2x6, R-19 batt, 

R6 sheathing 

R-19, 2x6, 

24 in. oc 

R-13, 2x4, 

16 in. oc 

R-19, 2x6, 

24 in. oc 

R-11, 2x4, 

16 in. oc 

R-19, 2x6, 

24 in. oc + 1-in. 

polyiso (R7) 

R-19, 2x6, 

24 in. oc 

R-

2

Ceiling U = 0.026, 11% FF R-38.5 R-40 FG R-40 FG R-30 FG R-50 FG R-30 FG R-40 FG R

Thermal Mass 

8 lbs/ft2 - furniture, 

standard light frame 

construction 

1⁄2-in. Ceiling 

Drywall 

1⁄2-in. Ceiling 

Drywall 

1⁄2-in. Ceiling 

Drywall 

Two 1⁄2-in. 

Ceiling Drywall 

Layers 

1⁄2-in. Ceiling 

Drywall 

1⁄2-in. Ceiling 

Drywall 

1⁄2-in

D

Infiltration SLA = 0.00057 SLA = 0.0003 SLA = 0.0003 SLA = 0.0003 SLA = 0.0003 SLA = 0.0003 SLA = 0.0003 SLA 

Basement Wall U = 0.095, R-10 4-ft R-5 Exterior Insulation 8-ft R-10 Exterior Insulation 4-ft R-5 Exterior Insulation 8-ft R-10 Exterior Insulation 4-ft R-5 Exterior Insulation 4-ft R-5 Exterior Insulation 4-ft R

In

Glass Type U = 0.39, SHGC = 0.32 

Two-pane, 

Low-e,

U = 0.29, 

SHGC = 0.29 

Center of Glass, 

insulated spacer, 

Vinyl frame 

Two-pane, 

Low-e,

U = 0.29, 

SHGC = 0.29 

Center of Glass, 

insulated spacer, 

Vinyl frame 

Two-pane, 

Low-e,

U = 0.29, 

SHGC = 0.29 

Center of Glass, 

insulated spacer, 

Vinyl frame 

Two-pane, 

Low-e,

 U = 0.29, 

SHGC = 0.29 

Center of Glass, 

insulated spacer, 

Vinyl frame 

Two-pane, 

Low-e,

U = 0.29, 

SHGC = 0.29 

Center of Glass, 

insulated spacer, 

Vinyl frame 

Two-pane, 

Low-e,

U = 0.32, 

SHGC = 0.64 

Center of Glass, 

insulated spacer, 

Vinyl frame 

Tw

L

U 

SHG

Cente

insula

Vin

Window Area per 

Wall 

540 ft2, Equal 

distance on four 

sides 

540 ft2, 

12.5% N&S, 

50% W, 25% E 

540 ft2, 

12.5% N&S, 

50% W, 25% E 

540 ft2, 

12.5% N&S, 

50% W, 25% E 

540 ft2, 

12.5% N&S, 

50% W, 25% E 

540 ft2, 

12.5% N&S, 

50% W, 25% E 

540 ft2, 

12.5% N&S, 

50% W, 25% E 

5

12.

50% 

Refrigerator 669 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Stan

k

Cooking Range 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 T

150 
Table B.3. BEopt Option Results for Two-Story Case (continued) 

Category Benchmark 

35% 

Point 

Neighbor 

1 

Neighbor 

2 

Neighbor 

3 

Neighbor 

4 

Neighbor 

5 

Dishwasher 206 kWh/yr, 5 gal DHW/day 

Standard, 

462 kWh, eight 

place setting 

capacity, 

131.6 kWh/yr 

machine energy, 

5.39 gal/day DHW 

ENERGY STAR,

384 kWh, eight 

place setting 

capacity, 

82.2 kWh/yr 

machine energy, 

3.76 gal/day DHW

Standard, 

462 kWh, eight 

place setting 

capacity, 

131.6 kWh/yr 

machine energy, 

5.39 gal/day DHW

Standard, 

462 kWh, eight place 

setting capacity, 

131.6 kWh/yr 

machine energy, 

5.39 gal/day DHW 

Standard, 462 kWh, 

eight place setting 

capacity, 

131.6 kWh/yr 

machine energy,

5.39 gal/day DHW 

ENERGY STAR, 

384 kWh, eight 

place setting 

capacity, 

82.2 kWh/yr 

machine energy,

3.76 gal/day DHW

Clothes Dryer 

Gas - 71.6 kWh/yr, 

31.3 Therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 

70.1kWh/yr, 

31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Clothes Washer 

105 kWh/yr, 

15 gal/day 

Standard, 3.15 ft3, 

533 kWh/yr, 

1.16 MEF, 

65.6 kWh/yr 

machine energy, 

4.63 gal/day DHW 

Standard, 3.15 ft3, 

533 kWh/yr, 

1.16 MEF, 

65.6 kWh/yr 

machine energy, 

4.63 gal/day DHW

Standard, 

3.15 ft3, 

533 kWh/yr, 

1.16 MEF, 

65.6 kWh/yr 

machine energy, 

4.63 gal/day DHW

Standard, 3.15 ft3, 

533 kWh/yr, 

1.16 MEF, 

65.6 kWh/yr machine 

energy, 

4.63 gal/day DHW 

Standard, 3.15 ft3

,

533 kWh/yr, 

1.16 MEF, 

65.6 kWh/yr 

machine energy, 

4.63 gal/day DHW 

Standard, 

3.15 ft3, 533 

kWh/yr, 

1.16 MEF, 

65.6 kWh/yr 

machine energy, 

4.63 gal/day DHW

Lighting 

14% CFL, 

2534 kWh/yr Hardwired, 

571 Plug in 

100% CFL, 

707 kWh/yr Hardwired, 

571 Plug in 

100% CFL, 

707 kWh/yr Hardwired, 

571 Plug in 

76% CFL, 

1206 kWh/yr Hardwired, 

571 Plug in 

100% CFL, 

707 kWh/yr Hardwired, 

571 Plug in 

14% CFL, 

2534 kWh/yr Hardwired, 

571 Plug in 

100% CFL, 

707 kWh/yr Hardwired, 

571 Plug in 

7

Air Conditioner 

SEER 10, 

0.55 W/CFM AH Fan 

SEER 10, 3 Tons, 

0.365 W/CFM AH 

Fan 

SEER 13, 3 Tons, 

0.365 W/CFM AH 

Fan 

SEER 15, 3 Tons, 

0.256 W/CFM AH 

Fan 

SEER 13, 3 Tons, 

0.365 W/CFM AH 

Fan 

SEER 10, 3 Tons, 

0.36 W/CFM AH Fan

SEER 10, 

3 Tons,

0.365 W/CFM AH 

Fan 

0

Furnace 78% AFUE 92.5% AFUE, 75 kBtu/hr 92.5% AFUE, 75 kBtu/hr 92.5% AFUE, 75 kBtu/hr 92.5% AFUE, 

75 kBtu/hr 

92.5% AFUE, 

75 kBtu/hr 

92.5% AFUE, 

75 kBtu/hr 

Ducts 

Basement, 

1.5% AH fan flow 

leakage to the 

outside 

Inside Conditioned 

Space, 

 SA leakage = 1%, 

OA leakage 0.23% 

of fan flow 

Inside Conditioned 

Space, 

SA leakage = 1%, 

OA leakage = 

0.23% of fan flow 

Inside Conditioned 

Space, 

SA leakage = 1%, 

OA leakage = 

0.23% of fan flow 

Inside Conditioned 

Space, 

SA leakage = 1%, 

OA leakage = 0.23% 

of fan flow 

Inside Conditioned 

Space, 

SA leakage = 1%,

OA leakage = 0.23% 

of fan flow 

Inside 

Conditioned 

Space, 

SA leakage = 1%, 

OA leakage = 

0.23% of fan flow

S

Water Heater Gas, 40 gal, 0.54 EF, 0.76 RE Gas Tankless, 0.84 EF Gas Tankless, 0.84 EF Gas Tankless, 0.84 EF Gas Tankless, 0.84 EF Gas Tankless, 0.84 EF Gas Tankless, 0.84 EF 

151 
Table B.4. BEopt Energy and Savings Results for Two-Story Case 

Benchmark 

35% 

Point 

Neighbor

1 

Neighbor

2 

Neighbor

3 

Neighbor

4 

Neighbor

5 

Next P

Optimiza

Energy End Use (MBtu/yr) 

Miscellaneous (E) 67.94 66.83 66.33 66.85 66.33 66.84 66.33 66

Lights (E) 25.98 9.08 9.08 13.66 9.08 25.98 9.08 9

Heating Fan (E) 9.18 5.15 5.44 3.78 5.47 4.56 4.47 5

Cooling Fan (E) 4.81 1.59 1.66 1.08 1.43 1.72 3.09 1Cooling (E) 20.59 11.20 9.30 7.64 8.00 12.09 22.29 11

Heating (G) 153.40 86.80 91.10 88.10 91.40 77.50 77.80 86

Hot Water (G) 23.69 15.75 15.32 15.75 15.32 15.75 15.32 15

Miscellaneous (G) 9.79 8.10 8.10 8.10 8.10 8.10 8.10 8Total 315.38 204.50 206.33 204.95 205.12 212.54 206.48 20

152 
153 

Table B.4. BEopt Energy and Savings Results for Two-Story Case (continued) 

Benchmark 

35% 

Point 

Neighbor

1 

Neighbor

2 

Neighbor

3 

Neighbor

4 

Neighbor

5 

Next P

Optimiza

End Use Savings 

Miscellaneous (E) 1.6% 2.4% 1.6% 2.4% 1.6% 2.4% 2

Lights (E) 65.1% 65.1% 47.4% 65.1% 0.0% 65.1% 65

Heating Fan (E) 43.9% 40.7% 58.8% 40.4% 50.3% 51.2% 43Cooling Fan (E) 66.9% 65.4% 77.5% 70.3% 64.2% 35.8% 66

Cooling (E) 45.6% 54.8% 62.9% 61.2% 41.3% -8.3% 45

Heating (G) 43.4% 40.6% 42.6% 40.4% 49.5% 49.3% 43

Hot Water (G) 33.5% 35.4% 33.5% 35.4% 33.5% 35.4% 35Miscellaneous (G) 17.2% 17.2% 17.2% 17.2% 17.2% 17.2% 17Total Energy Savings 35.2% 34.6% 35.0% 35.0% 32.6% 34.5% 35
BEopt Cost and Performance Input Assumptions 

As with any analysis study, the results of the analysis are subject to the assumptions used during 

the study. The cost and performance assumptions used in the present study are documented in 

this Appendix. These assumptions will be updated on a regular basis as new information 

becomes available from residential field studies. The use of specific manufacturer names in this 

Appendix does not represent an endorsement or recommendation for use of a specific product. 

This Appendix is limited to categories that include multiple options specific to the optimizations 

performed and may not representative of all the possible options currently available within 

BEopt. 

Table B.5. Utility and Onsite Power Inputs 

Group Input Variable Value Units 

Economics Electricity Source/Site Ratio 3 

Electricity Cost 0.0771 $/kWh 

Natural Gas Cost 0.8044 $/therm 

Discount Rate 0.05 

Mortgage Interest Rate 0.07 

Marginal Income Tax Rate 0.28 

Analysis Period 30 years 

Net Metered Excess Sellback 

Rate Local electric rate $/kWh 

Efficiency Cost Multiplier 1 

Photovoltaics Module Sharp NEH120E1 

Installed Cost 

7.5 (unless noted 

otherwise) $/rated W 

Derate Factor Determined by location % 

Daily Incident Solar Determined by location kWh/m2

Average System Efficiency Determined by location % 

Table B.6. BEopt Cost Assumptions 

154 
Category/Option Unit Cost 

Basement Insulation ($/ft) 

Uninsulated $0.00 

4-ft R-5 Exterior $1.68 

4-ft R-10 Exterior $3.08 

8-ft R-10 Exterior $6.16 

8-ft R-15 Exterior $8.96 

8-ft R-20 Exterior $9.84 

Wall Construction ($/ft2

) 

R-11 batts, 2x4, 16 in. oc $3.15 

R-13 batts, 2x4, 16 in.oc $3.17 

R-11 batts, 2x4, 16 in.oc + 1-in. foam sheathing $3.92 

R-19 batts, 2x6, 24 in. oc $3.28 

R-19 batts, 2x6, 24 in. oc + 1-in. foam sheathing $4.05 

R-19 batts, 2x6, 24 in. oc + 2-in. foam sheathing $4.24 

Ceiling Insulation ($/ft2

) 

R-30 Fiberglass $0.55 

R-40 Fiberglass $0.73 

R-50 Fiberglass $0.92 

R-60 Fiberglass $1.10 

155 
Table B.6. BEopt Cost Assumptions (continued) 

Category/Option Unit Cost 

Thermal Mass ($/ft2) 

Standard 1⁄2-in. Ceiling Drywall $0.19 

5/8-in. Ceiling Drywall $0.27 

2 x 1⁄2-in. Ceiling Drywall $0.38 

2 x 5/8-in. Ceiling Drywall $0.54 

Infiltration ($/ft2

) 

Typical (SLA = 0.0005) $0.00 

Tight (SLA = 0.0003) $0.54 

Windows ($/ft2

) 

Two-pane clear, U = 0.49, SHGC = 0.76, Center of Glass, 

insulated spacer, vinyl frame $21.99 

Low-e (e = 0.01), double-pane, U = 0.32, SHGC = 0.64 

Center of Glass, insulated spacer, vinyl frame $24.77 

Low-e (e= 0.1 w / tint), double-pane, U= 0.31, SHGC = 

0.37, Center of Glass, insulated spacer, vinyl frame $24.77 

Low-e (e = 0.04), double-pane, U = 0.3, SHGC = 0.44 

Center of Glass, insulated spacer, vinyl frame $24.77 

Low-e (e = 0.04 w / tint), double-pane, U = 0.29, SHGC = 

0.29 Center of Glass, insulated spacer, vinyl frame $24.77 

Heat Mirror (HM22), U = 0.21, SHGC = 0.14, Center of 

Glass, insulated spacer, Vinyl frame $30.32 

Heat Mirror (HM TC88), U=0.18, SHGC=0.48, Center of 

Glass, insulated spacer, vinyl frame $30.32 

156 
Table B.6. BEopt Cost Assumptions (continued) 

Category/Option Unit Cost 

Refrigerator ($/unit) 

Standard - 671 kWh/yr $1,099.99 

ENERGY STAR – 572 kWh/yr $1,219.99 

Dishwasher ($/unit) 

Standard, 462 kWh, eight place setting capacity, 

131.6 kWh/yr machine energy, 5.39 gal/day DHW $239.00 

ENERGY STAR, 384 kWh/yr, eight place setting capacity, 

82.2 kWh/yr machine energy, 3.76 gal/day DHW $299.00 

Clothes Washer ($/unit) 

Standard, 3.15 ft3

, 533 kWh/yr, 1.16 MEF, 65.6 kWh/yr 

machine energy, 4.63 gal/day DHW $419.00 

ENERGY STAR, top loader, H-axis, 2.9 ft3

, 273 kWh/yr, 

1.68 MEF, 72.9 kWh/yr machine energy, 3.71gal/day DHW $799.00 

Lighting ($/bulb) 

Incandescent $0.25 

CFL $7.99 

157 
Table B.6. BEopt Cost Assumptions (continued) 

Category/Option Unit Cost 

Air Conditioner SEER value 

Efficiency Cost ($) = 

0.817*((186*SEERvalue)-1535) 

10 $265.53 

12 $569.45 

13 $721.41 

14 $873.37 

15 $1,025.34 

16 $1,177.30 

17 $1,329.26 

18 $1,481.22 

Air Conditioner Capacity (tons) 

Capacity Cost ($) = 

0.817*(563*tons) 

0.5 $229.99 

1.0 $459.97 

1.5 $689.96 

2.0 $919.94 

2.5 $1,149.93 

3.0 $1,379.91 

3.5 $1,609.90 

4.0 $1,839.88 

158 
Table B.6. BEopt Cost Assumptions (continued) 

Category/Option Unit Cost 

Furnace Efficiency (% AFUE) 

Efficiency Cost ($) = 

(23.57*AFUE%*100)-1621 

80% $264.60 

92.5% $559.23 

Furnace Capacity (kBtu/hr) Capacity Cost ($) = 2.92*kBtu/hr

25 kBtu/hr $73.00 

50 kBtu/hr $146.00 

75 kBtu/hr $219.00 

100 kBtu/hr $292.00 

125 kBtu/hr $365.00 

150 kBtu/hr $438.00 

175 kBtu/hr $511.00 

200 kBtu/hr $584.00 

Water Heater ($/unit, install + equip) 

Gas Standard, 40 gallons, 0.55 EF $428.00 

Gas Premium, 40 gallon , 0.62 EF $624.08 

Gas Tankless, 0.84 EF $1,050.00 

Ducts ($/ft2

FFA) 

Typical, SA leakage = 10%, OA leakage = 2.3% of fan flow $0.45 

Improved, SA leakage = 2.3%, 

OA leakage = 0.5% of fan flow $0.69 

Inside Conditioned Space, SA leakage = 1%, 

OA leakage = 0.23% of fan flow $0.77 

159 
Appendix C. List of Key Trade-based Certifications 

Preferred Contractors Program Draft 

Below is a preliminary list of the different trade classifications and the sub-specializations that 

could be associated with a new-home certified contractors program. The concept is to have a 

broad range of specialist classifications, to acknowledge the fragmentation and specialization 

that is inherent in the construction industry. This encourages even those trades who do a very 

limited scope of work (i.e., just window installation or just duct rough in) to become certified 

specialists in their field, which requires them to also have a broader understanding of how that 

piece fits into the bigger house as a system. This concept will need to be discussed with 

manufacturers and trade contractors to determine its practicality. 

1. HVAC

A. Space-Conditioning System-Design Specialist 

B. Duct-Design Specialist 

C. Air-Distribution System-Installation Specialist 

D. Equipment-Installation and Start-up Specialist 

i. Fossil and electric heating 

ii. Refrigeration – AC / Heat Pump 

E. Airflow-Balancing Specialist 

2. Carpentry 

F. Framing Specialist 

3. Thermal envelope 

G. Insulation Specialist 

H. Air-sealing Specialist 

4. Above-grade Moisture Management 

I. Window- and Door-Installation Specialist 

J. Wall-Drainage-Plane Specialist 

K. Roof-Drainage and Flashing Specialist 

5. Below-grade Moisture Management 

L. Below-Grade Moisture-Management Specialist 

6. Designers 

M. Architect / Residential Designer 

N. Engineer 

160 
Within each of the specializations is a more detailed description of the probable roles and 

competencies required. 

1. HVAC

• Space-Conditioning System-Design Specialist 

o Load-calculation, Ventilation, and Equipment-selection Specialist 

– Proficiency in ACCA Manual J method for load calculation and how to account 

for higher performance when calculating heating and cooling loads 

– Understands relationship between high-performance house (thermal-envelope 

strategies to achieve high-performance homes) and heating and cooling loads to 

be satisfied by the space-conditioning equipment 

– Surface-area competencies and understanding of thermal-envelope assemblies 

(i.e., framing factors, window properties, etc.) 

– Understands the types of ventilation systems and their interaction with the heating 

and cooling equipment 

– Understands dedicated humidity-control options and how to integrate with spaceconditioning systems 

– Understands the internal gains and latent loads associated with people and 

ventilation 

– Understands the impact of climate, shading, and other environmental impacts on 

the building 

o Duct-Design Specialist 

– Understands the impact of duct friction with respect to airflows (equivalent length 

methods – ACCA Manual D) 

– Familiarity with structural systems and limitations regarding using running-duct 

systems within structural systems (floor framing systems, walls, etc.) 

– Air-distribution options in higher performance homes (high sidewall, central 

return, etc.) 

– Acoustics of air-distribution systems 

• Air-Distribution System-Installation Specialist 

o Follows layout by Duct-Design Specialist 

o Understands duct-dealing techniques 

o Understands ventilation-system concepts as they relate to ducts and equipmentinstallation issues 

o Certified in duct-system leakage testing 

o Sets furnace and inside AC coils as part of air system 

161 
• Equipment-Installation and Start-up Specialists 

o Installation of equipment and associated refrigeration 

o Start-up and commissioning of heating, cooling, and ventilation systems 

• Airflow-Balancing Specialist 

o Airflow at the equipment

o Total-system duct-leakage testing 

o Room-by-room airflow balancing and measurement 

2. Carpentry 

• Framing Specialist 

o Optimum-value engineering of wood-frame structures 

– Stack framing 

– Wall layout and value-engineering wall-framing techniques 

– Floor framing and interaction with HVAC system and plumbing system 

– Structural and code limitations 

o Air-sealing techniques incorporated during framing (i.e., band-joist gluing and sealing, 

mud-sill sealing, cantilevers, floors over garages, chases, etc.) 

3. Thermal envelope 

• Insulation Specialist 

o Insulation basics 

o How insulation works 

o Encapsulation requirements 

o Types of insulation products, limitations, and applications 

o Insulation and flame-spread issues 

o Blown-in wall techniques (new and retrofit) 

o Damp spray 

o Net and fill cavity 

o Two-hole method 

o Hole and tube (dense pack) 

o Blown attic and horizontal cavity (floor, cantilever, etc.) 

o Batt installation 

o Below-grade insulation systems (interior) 

o Crawl-space vapor-barrier installation 

162 
o Sub-Specialist designation 

• Air-Sealing Specialist 

o Envelope air-tightening techniques 

o Window and door rough openings 

o Framing intersections 

o Bypasses / chases / soffits 

o Cantilevers, floors over unconditioned spaces 

o Fire codes and safety 

o Diagnostics 

o Blower door 

o Pre- and post-testing 

o Blower-door directed air-sealing techniques 

o Infrared imaging 

o Pressure diagnostics 

4. Above-grade Moisture Management 

• Window- and Door-Installation Specialist 

o Flashings 

o Integration to drainage plane 

• Wall-Drainage-Plane Specialist 

o Drainage-plane installation 

o Integration with windows and doors 

o Integration with roof-flashing systems 

o Roof-flashing systems at wall intersections 

• Roof-Drainage and Flashing Specialist 

o Roof-penetration flashings 

o Roof-wall flashing systems 

o Integration to wall systems 

o Gutter and downspouts 

163 
164 

5. Below-grade Moisture Management 

• Below-Grade Moisture Management Specialist 

o Perimeter drainage systems 

o Sub-slab capillary break and vapor-diffusion control 

o Capillary break at footing 

o Vapor barrier at crawl spaces 

o Foundation damp-proofing systems 

o Foundation waterproofing systems 

6. Designers 

• Architect / Residential Designer 

• Engineer 
Appendix D: National Housing Quality Rating Table 

Table D.1. Leadership Leaders align everyone in the organization with a common purpose, values, and priorities. 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

1.1 Company Mission, Vision, and Values 

Company's main quality goal is to avoid customer disappointment and complaints. 

Quality and customer satisfaction is important to the company but not included in a written mission statement. 

Written company mission statement includes a commitment to quality and customer satisfaction. 

Quality is defined in the five key performance metrics (Health, Safety, Durability, Efficiency & Comfort) with measurable attributes associated with the definition. 

In addition to level 3, values or principles important to the company are included in a written statement. 

PoBtei

1.2 Senior Management Involvement 

Senior managers get involved with 

quality to handle customer complaints. 

Senior managers like the idea of quality but 

are not involved in improvement activities. 

Senior managers demonstrate personal commitment to the company's quality mission and are often involved in qualityrelated activities 

Performance attributes are given equal weight to other quality criteria. Quality Management is a cross-cutting management function 

Senior managers constantly communicate the company's quality mission to customers, employees, and trade contractors. 

OfpodwStp

1.3 Leadership 

Feedback and Improvement 

Senior management uses 

their experience to guide the company toward their vision for the future. 

Senior managers actively seek 

employee feedback to gauge the organization’s alignment toward the company mission, vision, and values. 

In addition to level 2, surveys measure the alignment of employee values and beliefs toward those of the organization. 

Performance metrics are included in survey 

In addition to level 3, senior managers plan initiatives to reinforce the company mission, vision, and values. 

Pai

165 
Table D.1. Leadership (continued) 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

1.4 Living the Mission 

Employees may have different priorities but there is a general understanding of what the company is trying to accomplish. 

Most employees know key elements of the company mission, values, and vision for the future and could explain how it relates to their job. 

Most employees recognize and support organizational mission, values, and vision, and use them to guide their decision making. 

Performance metrics are instilled as one component that is used in decision making 

In addition to level 3, survey data shows that most employees embrace the company mission, vision, and values. There is a strong feeling that everyone is working toward common goals. 

Spaeuipa

1.5 Public Responsibility 

Some people at the company are personally involved in activities that benefit the community, the public, or the housing industry. 

When asked, the company supports activities to benefit the community, the public, or the housing industry. 

Being a responsible corporate citizen is regarded as good for the company. The company is actively involved in activities to benefit the community, the public, or the housing industry. 

Company involvement is related to performance metrics 

In addition to level 3, the company creates opportunities to be actively involved in activities to benefit the community, the public, or the housing industry. 

Cap

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set.

166
Table D.2. Strategic Planning 

Achieving a future vision of what the company can become requires creating and executing a strategic plan for getting there. 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 IB

2.1 Company-wide Success Drivers and Performance Measures. 

Measures of company 

performance are limited to sales and profit. 

In addition to level 1, customer satisfaction 

is important, but performance data is not tracked. 

The current customer satisfaction rating is one of the company’s monthly performance measures communicated to all employees. 

Customer satisfaction measurements include consumer feedback on performance metrics, and limited testing to verify performance metrics are being achieved 

In addition to level 3, company-wide performance measures link directly to key success drivers for achieving the company mission and vision. 

Lssspp

2.2 Strategic Plans 

Company improvement 

strategy is to increase sales and reduce costs, but specific action plans are not in place. 

The company's competitive business 

strategy includes improving customer satisfaction and products that enhance homeowner value. 

In addition to level 2, written improvement plans are in place with measurable goals. Plans explain how performance improvement goals will be achieved. 

Written improvement plans include performance standards and testing requirements. Plan outlines cross functional leader for performance-based quality initiative 

In addition to level 3, strategic plans link directly to improvement of company-wide performance measures and fully support the company's mission and values. 

Pminc

2.3 Plan Deployment 

The senior managers who 

make the strategic plans also carry out the improvement initiatives. Employees are involved on an asneeded basis. 

Senior managers develop the strategic plan with some employee input. The plan is used to set departmental objectives. 

In addition to level 2, senior managers 

organize employee teams to carry out improvement projects that may involve multiple departments. 

A systematic process is in place for involving most employees in the development of strategic objectives, carrying out action plans to achieve them, and monitoring progress. 

Minpsuthwla

2.4 Monitoring 

Progress to Plan 

Progress is monitored on an 

as-needed basis. 

Quarterly review meetings monitor improvement progress. 

Monthly review meetings monitor 

actual versus planned improvement activities. Adjustments to plans are made to accommodate current status. 

Measurements of key performance attributes are made to judge achievement of goals 

In addition to level 3, measurement data is used to monitor performance toward strategic objectives. 

Tfuecim

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set.

167
Table D.3. Customer Satisfaction 

Sustaining high levels of customer satisfaction requires performing well from the customer’s point of view. 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 IB

3.1a Market Research 

Market requirements are 

learned mainly from customer requests. 

In addition to level 1, market trends are 

learned from tours of other builders' products and builder magazines. 

In addition to level 2, detailed price and feature comparisons with other builders are used to analyze competitive position and uncover unfilled market niches. Feedback from lost customers is used to analyze unfilled needs. 

Product is Benchmarked compared to national and local standards. Feedback strategies also capture data regarding performance attributes 

In addition to level 3, markets are analyzed by demographic groups. Surveys or focus groups identify customer preferences for features and services. 

Finkfea5p

3.1b Product Design Processes 

A company expert or consultants 

create new home designs. 

In addition to level 1, select employees 

provide some input into the design process. 

A new home design team includes construction and sales personnel. 

In addition to level 3, homeowners, employees, and trade contractors are systematically included in the home design process. 

Pspuinpa p

3.2 Customer 

Satisfaction Drivers 

Avoiding homeowner 

disappointment with the constructed product is the main customer satisfaction priority. 

Completing the home on time with a short 

punch list at final inspection is the company’s main focus for satisfying customers. 

In addition to level 2, the customer experience and relationship with the builder are important customer satisfaction drivers. Meeting customer expectations is recognized as the key to reliably satisfying customers. 

Builder monitors expectation set by other builders, and seeks to set similar consumer expectations through sales process 

Exceeding customer expectations is an important company priority. Employees understand how their team and department performance contributes to overall customer satisfaction. 

Bctsma

168
Table D.3. Customer Satisfaction (continued) 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 IB

3.3 Customer Relationship Management 

Maintaining good customer 

relationships through final inspection is the main priority. Everyone has his or her own way of working with customers, with varying degrees of effectiveness. 

Maintaining good customer relationships 

through the end of the warranty period is the main priority. Policies for dealing with customers are in place for the sales process. 

Relationships with customers are recognized as a key customer satisfaction driver. A process is in place for creating positive customer relationships in sales, construction, and service phases. 

In addition to level 3, customer expectations for key customer satisfaction drivers are systematically managed throughout the customer relationship. Customers are viewed as customers for life. 

Kins

3.4a Customer Satisfaction Measurement 

Customer satisfaction 

feedback data consists of final inspection punch lists and warranty callbacks. 

Customer satisfaction is measured 

occasionally by surveys or by asking customers. Some questions ask customers to rate employee performance. 

All customers are surveyed on their satisfaction with the home and the customer experience during the sales, construction, and warranty service periods. Questions focus on process performance rather than employee ratings. 

Survey links expectations of housing performance compared to actual experience of living in home (i.e., comfort, energy performance, durability, noise, etc.) 

In addition to level 3, customer satisfaction survey questions are directly linked to known customer satisfaction drivers. 

Mcinkd

3.4b Sharing of 

Customer Satisfaction Feedback 

Customer complaints are 

shared with the persons responsible. 

Customer letters and surveys are routinely 

circulated among employees. 

In addition to level 2, Summary customer satisfaction data is available to all employees. Trends are tracked and posted for all to see. Senior managers frequently discuss customer feedback with employees. 

Customer satisfaction ratings are routinely communicated to the organization as one of the company-wide performance measures. Relevant customer satisfaction data is shared with suppliers and trade contractors. 

Pins

169
Table D.3. Customer Satisfaction (continued) 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

3.5 Customer Satisfaction Results 

Percentage of customers who 

would recommend the company to a friend is not measured. 

More than 75% of customers surveyed 

would recommend the company to a friend. Customer satisfaction seems to be improving. 

More than 85% of customers surveyed would recommend the company to a friend. There are measured improvements in customer satisfaction. 

More than 85% of customers surveyed feel home meets the company standard of performance 

More than 90% of customers surveyed would recommend the company to a friend. Customer satisfaction shows measured improvements in most products and services. 

Mcfecp

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set. 

170
Table D.4. Performance Management 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

4.1a Creating HighPerformance Work Processes 

Meeting minimum performance 

expectations is an important priority for most employees. 

Most employees have well-defined 

responsibilities. Finding ways to reduce costs is the main focus of work improvement activities. 

Key work processes are well defined. Customer satisfaction and cost are important work improvement priorities. 

“Building performance quality management” has been identified as a key work process, and has been assigned within the organization 

Customer needs drive work systems design and improvements. Some work systems are modeled on industry best practices. 

Tpm

4.1b Bench-Marking Business Processes 

Information on how other builders do 

things is obtained mostly from publications and seminars. 

Occasional visits to other builders are 

made to get some good ideas. 

Regular visits to other builders are made to compare performance results and set improvement objectives. 

Those builders visited include others who are improving building performance at Level 3 and at least one at Level 4 

In addition to level 3, detailed studies of other builders’ operations are used to design operational improvements. 

TinimpaL

4.2 Performance 

Management 

Performance is managed by 

monitoring the productivity of individual employees. 

In addition to level 1, conformance to 

department budgets is used to manage financial performance. 

Performance management focuses on the productivity of key business processes. Results are tracked and reviewed monthly. 

Building to a predefined performance standard is identified as a key business process 

In addition to level 3, key work processes have performance measures that link directly to companywide key success measures. Results are shared with all employees. 

Pau

4.3 Process 

Improvement 

Problems are handled as they

occur to avoid customer complaints. 

Changes to company processes are made 

occasionally to prevent recurring problems. Some employees are involved in improvement projects. 

Improving company processes is an important part of everyone’s job. There are many improvements made throughout the company. The company uses a systematic method to make improvements. 

Process of designing and building for performance is identified as a key process improvement area 

An effective strategy and goals are in place for involving the entire workforce in problem solving and quality improvement. Most employees have been trained in the company’s process improvement methods. 

Qmwcp

171
Table D.4. Performance Management (continued) 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

4.4 Improvement Results 

Some company work processes seem to 

be improving, but there are no measures of progress. 

Some company work processes show 

measured quality improvements. 

Most company work 

processes show measured quality improvements. 

Most company work processes show measured quality improvements and excellent quality results. 

Pam

4.5 Financial Improvement Results 

Some improvements have resulted in cost 

reductions. 

Substantial cost reductions have been 

made but have not yet helped improve home sales. 

Home sales and company profitability show improvement. 

Profitability is in some way attributable to performance standards (reduction in callbacks, improved value, etc.) 

Company's share of home sales is increasing. Company profitability shows excellent results with positive trends. 

Mmcpcto p

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set. 

172
Table D.5. Human Resources 

The human resources system must develop the full potential of employees and drive the right behaviors in support of company performance and learni

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

5.1a Employee Satisfaction 

The company shows a general concern for 

employee well-being and morale. 

Company shows that employee well-being and morale are priorities in making business decisions. There are occasional morale-building activities. 

In addition to level 2, employee satisfaction 

is recognized as important for the company’s success. Senior managers take initiatives to do what they think will improve the work environment. 

The company understands which factors drive employee satisfaction. Employee surveys measure employee satisfaction and the information is used to improve the work environment. 

Rpamce

5.1b Jobsite Safety 

There are occasional safety-related training 

activities. 

Health and safety training is provided to all field employees. 

Company shows that employee health and safety are priorities in making business decisions. 

In addition to level 3, there is an organized approach to analyzing causes of injuries and preventing accidents. 

5.1c Job Responsibilities 

Employees learn job responsibilities from 

on-the-job experience. 

Job descriptions define job responsibilities. 

In addition to level 2, most employees clearly understand their job responsibilities and how their job contributes to company performance. 

Job Responsibilities are also tied to Building Performance 

In addition to level 3, employees feel responsible for performing their job to meet the needs of other employees who depend on them. 

Orpsa

5.1d Teamwork 

Individual effort is the main way things get 

done. 

Some natural work groups are formed into operating teams with shared responsibilities. 

Most employees are part of an operating team with a wellunderstood purpose. Teams are the main way that day-to-day work gets done. 

Performance attributes and standards are part of the purpose within a team 

In addition to level 3, teamwork is the primary mechanism for solving problems and making performance improvements. 

Pibsi

173
Table D.5. Human Resources (continued)

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

5.2 Workforce Development 

Skills are learned on the job. 

Work-related training is delivered as needed when time and budget allows. 

There is a company training budget. Most employees receive some training. Most employees have personal training and development plans. 

Key general training on issues related to building-performance standards is provided and specifically related to company performance standards 

In addition to level 3, the company’s training and hiring plan is aimed at developing the skills necessary for achieving the longrange company vision. 

Tpsef

5.3 Employee Evaluation and Compensation Systems 

Most employees receive an annual 

performance review. 

Annual employee performance reviews have well-defined evaluation criteria. Bonuses and recognition reward individual efforts. 

In addition to level 2, employee performance evaluation criteria are linked to job descriptions. Bonuses focus on team efforts. 

Evaluation criteria include measurement of achievement of building-performance standards 

Employee performance evaluation criteria are based on fulfillment of personal development plans and key elements of the company mission, vision, and values. 

Bst

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set.

174
Table D.6. Quality Construction Processes 

Systematic quality management approaches are necessary to ensure high performing, trouble-free products and services. 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 IB

6.1 Setting Quality Expectations 

Informal standards exist. "We know if it's 

OK when we see it." 

Construction details and workmanship 

specifications control known problem areas. 

In addition to level 2, the builder, contractor, and other trades collaborate to set quality requirements. Contract scopes of work reference specific construction standards and workmanship tolerances. 

Performance standards are selected and adopted by builders to meet or exceed Benchmark levels in region 

In addition to level 3, requirements analysis of building codes, construction standards, product installation instructions, and industry guidelines are used to set quality specifications. 

Beleoba

6.2 Assuring Quality Results 

The company fixes any defects the 

homeowner may find at final walk-through or during the warranty process. 

Construction personnel use their experience to 

catch defects. 

There are inspection checklists for most trades. Formal inspections are performed for each phase of construction by the builder. 

Performance standards are included on checklists, some performance testing is included 

In addition to level 3, trade contractors use checklists to perform quality self-inspections. The main function of builder inspections is to monitor quality performance rather than screen out defects from trade contractors. 

Psolete

6.3 Quality 

Problem Prevention 

Quality problems are corrected as needed. 

In addition to level 1, actions are taken to 

prevent chronic problems. 

Defect data is recorded, trends monitored, and improvement objectives are set. Actions to solve defect problems occur regularly. 

Troubleshooting activities use building science basis for performance based defect analysis 

In addition to level 3, systematic analysis of root causes are routinely used to prevent defects. Defect prevention focuses on improving processes. 

Mto pp

175
Table D.6. Quality Construction Processes (continued)

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 IB

6.4 Warranty Service 

Service callbacks are handled but not 

tracked. 

Systems are in place to track warranty 

complaints and their completion. 

In addition to level 2, warranty service data is used to set priorities for solving quality problems. 

Warrantee service data is broken down to capture root causes 

In addition to level 3, response time and customer satisfaction with each service call are important performance measures. 

Kdtrto cc

6.5 Product and Service Quality Results 

Product and service quality seems to be 

improving, but there are no measures of progress. 

Problems found at final inspection are 

decreasing. There are fewer callbacks. 

Data shows that constructed quality is improving. 

Quality is defined according to building science based performance metrics 

Most product and service quality performance indicators show excellent results with positive trends. Zero defect final inspections are commonplace. 

Dmsmate

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set.

176
177

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 IB

7.1 Trade Contractor and Supplier Relationships 

Difficult quality problems are usually 

solved by changing contractors or suppliers. 

A systematic process is in place for the 

selection of trade contractors. Trades and suppliers participate in solving problems. 

Key trade contractors and suppliers are considered partners. Company helps them improve quality and reduce costs. 

Performance standards are a metric of quality, testing measures improvement 

In addition to level 3, most major trade contractors and suppliers participate in a systematic approach to problem-solving and quality improvement. 

Cinpto cbspp

7.2 Trade Development 

There are no formal initiatives to develop 

the capabilities of trade contractors. 

Improving trades is focused on solving 

problems. 

A general strategy is in place to develop the capabilities and performance of trade contractors. 

Builder provides general training on Performance standards and trades relation to standards 

The company’s trade development plans are linked directly to achieving the company’s long-range vision. 

Tusinathpa

7.3 Trade 

Contractor Performance Management 

Trade performance is evaluated when 

problems arise or when contracts are renewed. 

Trade performance data consists of 

inspection punch lists and callbacks, but trend data is not tracked. 

Trade performance trend data is tracked and reviewed regularly with the key trades and used to improve quality and prevent defects. 

Primary use is checklists, some performance test data used to gauge trade against performance standards 

Customer satisfaction survey data on construction workmanship is used as a trade performance indicator. 

Pufo

7.4 Trade 

Contractor and Supplier Results 

Trade contractor quality seems to be 

improving, but there are no measures of progress. 

Some trade contractors show 

measured quality improvements. 

All major trade contractors show measured quality improvements. 

Measurement system includes key performance attributes 

All major contractors show excellent quality results. Most trade contractors routinely meet quality standards. 

Qins

Partnering approaches are essential for high performance relationships with trade contractors and product manufacturers. Table D.7. Supplier Partnerships 
NHQ Rating Form

Rating 

(circle your choice) 

1. Leadership 

1.1 Company Mission, Vision and Values 1 2 3 4 5 ? 

1.2 Senior Management Involvement 1 2 3 4 5 ? 

1.3 Leadership Feedback and Improvement 1 2 3 4 5 ? 

1.4 Living the Mission 1 2 3 4 5 ? 

1.5 Public Responsibility 1 2 3 4 5 ? 

2. Strategic Planning 

2.1 Company-wide Success Drivers and Performance 

Measures 

1 2 3 4 5 ? 

2.2 Strategic Plans 1 2 3 4 5 ? 

2.3 Plan Deployment 1 2 3 4 5 ? 

2.4 Monitoring Progress to Plan 1 2 3 4 5 ? 

3. Customer Satisfaction 

3.1a Market Research 1 2 3 4 5 ? 

3.1b Product Design Processes 1 2 3 4 5 ? 

3.2 Customer Satisfaction Drivers 1 2 3 4 5 ? 

3.3 Customer Relationship Management 1 2 3 4 5 ? 

3.4a Customer Satisfaction Measurement 1 2 3 4 5 ? 

3.4b Sharing of Customer Satisfaction Feedback 1 2 3 4 5 ? 

3.5 Customer Satisfaction Results 1 2 3 4 5 ? 

4. Performance Management 

4.1a Creating High Performance Work Processes 1 2 3 4 5 ? 

4.1b Benchmarking Business Processes 1 2 3 4 5 ? 

4.2 Performance Management 1 2 3 4 5 ? 

4.3 Process Improvement 1 2 3 4 5 ? 

4.4 Improvement Results 1 2 3 4 5 ? 

4.5 Financial Improvement Results 1 2 3 4 5 ? 

5. Human Resources 

5.1a Employee Satisfaction 1 2 3 4 5 ? 

5.1b Jobsite Safety 1 2 3 4 5 ? 

5.1c Job Responsibilities 1 2 3 4 5 ? 

5.1d Teamwork 1 2 3 4 5 ? 

5.2 Workforce Development 1 2 3 4 5 ? 

5.3 Employee Evaluation and Compensation Systems 1 2 3 4 5 ? 

6. Quality Construction Processes 

6.1 Setting Quality Expectations 1 2 3 4 5 ? 

6.2 Assuring Quality Results 1 2 3 4 5 ? 

178
NHQ Rating Form

Rating 

(circle your choice) 

6.3 Quality Problem Prevention 1 2 3 4 5 ? 

6.4 Warranty Service 1 2 3 4 5 ? 

6.5 Product and Service Quality Results 1 2 3 4 5 ? 

7. Supplier Partnerships 

7.1 Trade Contractor and Supplier Relationships 1 2 3 4 5 ? 

7.2 Trade Development 1 2 3 4 5 ? 

7.3 Trade Contractor Performance Management 1 2 3 4 5 ? 

7.4 Trade Contractor and Supplier Results 1 2 3 4 5 ? 

179
NHQ Survey information Information 

Champion 

Company Mission, Vision and Values

• What are the company mission statement, core values, and vision 

for the future? How is this documented and communicated 

amongst the staff? 

• How do senior managers demonstrate a commitment to the 

company mission, values, and vision, and to what extent does 

this translate to the actions of others throughout the organization? 

• What feedback mechanisms exist from field to management 

relating to company’s ability to deliver to the company mission, 

values, and progress towards vision? 

• How does the company understand if employees are in alignment 

with the company mission, values, and vision, and are there 

activities that specifically encourage and reinforce that alignment? 

• Does the company facilitate and coordinate opportunities to 

benefit the local community in alignment with the mission, values, 

and vision? 

Strategic Planning 

• What measurement mechanisms exist to evaluate if the company 

is achieving the mission, progressing towards the vision, and 

achieving customer satisfaction and operational performance 

metrics? 

• Is there a written strategic plan that documents the improvement 

process in different operational areas, the tools and systems used 

to identify areas of weakness and measure company-wide 

operational improvements, a detailed strategic plan for 

improvements in key areas, and who is involved in developing 

specific strategic improvement plans? 

• What process is in place to implement the plan, and how far 

throughout the organization does implementation reach? 

• What mechanisms are used and how often is review performed to 

monitor how well the organization is improving relative to the 

strategic plan? How often is the strategic plan updated? 

180
NHQ Survey information Information 

Champion 

Customer Satisfaction 

• What market research mechanisms are in place to understand 

customers, position relative to local competition, and forward 

positioning of products based on leading indicators (e.g., 

demographics, economic, style, etc.) 

• What is the design process? Who is involved? What feedback 

mechanisms exist? 

• What importance is placed on customer satisfaction, and how is 

that expressed in the company mission, values, and vision? 

• What process is in place to guide the customer through the sales 

and construction process? 

• How is customer satisfaction measured and used throughout the 

company to improve the customer relationship process? 

Performance Management 

• How does the organization set up work processes, identify work 

process improvements, and Benchmark against other industry 

and non-industry top performers? 

• How are work processes measured, and do they support key 

company wide success measures? 

• How are work-processes evaluated and improved? 

• How are work-processes tied to the quality of the house? 

• How are company financial results measured, and tied to work 

processes? 

Human Resources 

• Are employees are surveyed on job satisfaction and have input 

on improving employee satisfaction? 

• What is the company safety plan, and how far into the 

organization does it reach? 

• How empowered are employees with respect to their job and 

achieving key success metric? 

• How are teams utilized to perform management functions within 

the organization? 

• What kind of the training and employee development program 

exists in the company? 

181
NHQ Survey information Information 

Champion 

• How are employees and teams evaluated, compensated, and 

given incentive toward key success measures for the company 

Quality Construction Process 

• What are the company’s quality standards, and how are these 

communicated throughout the organization and to trades? 

• How do management, field, and trades monitor consistency and 

delivery of product that meets quality standards? 

• How do the company and the trades monitor and evaluate quality 

problems and develop process improvements to eliminate 

problems? 

• How is warranty service used to identify and fix root causes of 

quality problems? 

• How have these improvements contributed to zero defect at final 

inspection, and show positive trends in quality improvement and 

excellent results 

Supplier Partnerships 

• How are trade contractors and suppliers engaged in the 

company’s quality initiatives? 

• What strategies are in place to align trade contractors with the 

company mission, values, and vision; develop the trades to 

achieve quality standards; and provide financial rewards for 

achieving quality goals? 

• How is trade contractor performance tracked, and how is that 

data used to continually improve the trade contractor’s 

performance? 

• What are the results associated with the trade contractor 

initiatives? 

182
Appendix E. SNAPSHOT Form 

183 
F1147-E(12/2004) 

REPORT DOCUMENTATION PAGE Form Approved 

OMB No. 0704-0188

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, 

gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this 

collection of information, including suggestions for reducing the burden, to Department of Defense, Executive Services and Communications Directorate (0704-0188). Respondents 

should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a 

currently valid OMB control number. 

PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION.

1. REPORT DATE (DD-MM-YYYY)

August 2006 

2. REPORT TYPE

Subcontractor Report 

3. DATES COVERED (From - To)

January 2005 - November 2005 

5a. CONTRACT NUMBER

DE-AC36-99-GO10337 

5b. GRANT NUMBER

4. TITLE AND SUBTITLE

Building America Residential System Research Results: Achieving 

30% Whole House Energy Savings Level in Cold Climates 

5c. PROGRAM ELEMENT NUMBER

5d. PROJECT NUMBER

NREL/SR-550-38783 

5e. TASK NUMBER

BET6.8004 

6. AUTHOR(S)

Building Industry Research Alliance (BIRA); Building Science 

Consortium (BSC); Consortium for Advanced Residential Buildings 

(CARB); Florida Solar Energy Center (FSEC); IBACOS; National 

Renewable Energy Laboratory (NREL) 

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

National Renewable Energy Laboratory 

1617 Cole Blvd. 

Golden, CO 80401-3393 

8. PERFORMING ORGANIZATION 

REPORT NUMBER

NREL/SR-550-38783 

10. SPONSOR/MONITOR'S ACRONYM(S)

NREL 

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

11. SPONSORING/MONITORING 

AGENCY REPORT NUMBER

12. DISTRIBUTION AVAILABILITY STATEMENT

National Technical Information Service 

U.S. Department of Commerce 

5285 Port Royal Road 

Springfield, VA 22161 

13. SUPPLEMENTARY NOTES

NREL Technical Monitors: R. Anderson, R. Hendron, M. Eastment, and A. Jalalzadeh-Azar 

14. ABSTRACT (Maximum 200 Words)

The Building America program conducts the system research required to reduce risks associated with the design and 

construction of homes that use an average of 30% to 90% less total energy for all residential energy uses than the 

Building America Research Benchmark, including research on homes that will use zero net energy on annual basis. 

To measure the program’s progress, annual research milestones have been established for five major climate 

regions in the United States. The system research activities required to reach each milestone take from 3 to 5 years 

to complete and include research in individual test houses, studies in pre-production prototypes, and research 

studies with lead builders that provide early examples that the specified energy savings level can be successfully 

achieved on a production basis. This report summarizes research results for the 30% energy savings level and 

demonstrates that lead builders can successfully provide 30% homes in Cold Climates on a cost-neutral basis. 

15. SUBJECT TERMS

Building America; U. S. Department of Energy; systems research; cold climates; 30% energy savings level; energy 

efficient housing 

16. SECURITY CLASSIFICATION OF: 19a. NAME OF RESPONSIBLE PERSON 

a. REPORT 

Unclassified 

b. ABSTRACT 

Unclassified

c. THIS PAGE 

Unclassified

17. LIMITATION 

OF ABSTRACT

UL 

18. NUMBER 

OF PAGES 

19b. TELEPHONE NUMBER (Include area code)

Standard Form 298 (Rev. 8/98) 

Prescribed by ANSI Std. Z39.18
Bringing you a prosperous future where energy is clean, abundant, reliable, and affordable

A Strong Energy Portfolio 

for a Strong America

Energy efficiency and clean, renewable 

energy will mean a stronger economy, 

a cleaner environment, and greater 

energy independence for America. 

Working with a wide array of state, 

community, industry, and university 

partners, the U.S. Department of 

Energy’s Office of Energy Efficiency 

and Renewable Energy invests in a 

diverse portfolio of energy technologies.

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 energy-efficient 

components, materials, and 

equipment

• Technology Integration

Integration of new technologies 

with innovative building methods 

to optimize building performance 

and savings

For more information contact:

EERE Information Center

1-877-EERE-INF (1-877-337-3463)

www.eere.energy.gov

An electronic copy of this publication is 

available on the Building America Web 

site at www.buildingamerica.gov

U.S. Department of Energy

Energy Efficiency

and Renewable Energy

Building America Program

George S. James • New Construction • 202-586-9472 • fax: 202-586-8134 • e-mail: George.James@ee.doe.gov

Terry Logee • Existing Homes • 202-586-1689 • fax: 202-586-4617 • e-mail: terry.logee@ee.doe.gov

Lew Pratsch • Integrated Onsite Power • 202-586-1512 • fax: 202-586-8185 • e-mail: Lew.Pratsch@hq.doe.gov

Building America Program • Office of Building Technologies, EE-2J • U.S. Department of Energy • 1000 Independence Avenue, S.W. • 

Washington, D.C. 20585-0121 • www.buildingamerica.gov

Building Industry Research Alliance (BIRA)

Robert Hammon • ConSol • 7407 Tam O’Shanter Drive #200 • Stockton, CA 95210-3370 • 209-473-5000 • fax: 209-474-0817 • 

e-mail: Rob@consol.ws • www.bira.ws

Building Science Consortium (BSC)

Betsy Pettit • Building Science Consortium (BSC) • 70 Main Street • Westford, MA 01886 • 978-589-5100 • fax: 978-589-5103 • 

e-mail: Betsy@buildingscience.com • www.buildingscience.com

Consortium for Advanced Residential Buildings (CARB)

Steven Winter • Steven Winter Associates, Inc. • 50 Washington Street • Norwalk, CT 06854 • 203-857-0200 • fax: 203-852-0741 • 

e-mail: swinter@swinter.com • www.carb-swa.com

Davis Energy Group

David Springer • Davis Energy Group • 123 C Street • Davis, CA 95616 • 530-753-1100 • fax: 530-753-4125 •

e-mail: springer@davisenergy.com • deg@davisenergy.com • www.davisenergy.com/index.html

IBACOS Consortium

Brad Oberg • IBACOS Consortium • 2214 Liberty Avenue • Pittsburgh, PA 15222 • 412-765-3664 • fax: 412-765-3738 •

e-mail: boberg@ibacos.com • www.ibacos.com

Industrialized Housing Partnership (IHP)

Subrato Chandra • Florida Solar Energy Center • 1679 Clearlake Road • Cocoa, FL 32922 • 321-638-1412 • fax: 321-638-1439 • 

e-mail: subrato@fsec.ucf.edu • www.baihp.org

National Association of Home Builders (NAHB) Research Center

Tom Kenney • National Association of Home Builders (NAHB) Research Center • 400 Prince George’s Boulevard • 

Upper Marlboro, MD 20774 • 301-430-6246 • fax: 301-430-6180 • toll-free: 800-638-8556 • www.nahbrc.org/ 

National Renewable Energy Laboratory

Ren Anderson • 1617 Cole Boulevard, MS-2722 • Golden, CO 80401 • 303-384-7433 • fax: 303-384-7540 • 

e-mail: ren_anderson@nrel.gov • www.nrel.gov

Tim Merrigan • 1617 Cole Boulevard, MS-2722 • Golden, CO 80401 • 303-384-7349 • fax: 303-384-7540 • 

e-mail: tim_merrigan@nrel.gov • www.nrel.gov

Oak Ridge National Laboratory

Pat M. Love • P.O. Box 2008 • One Bethel Valley Road • Oak Ridge, TN 37831 • 865-574-4346 • fax: 865-574-9331 • 

e-mail: lovepm@ornl.gov • www.ornl.gov

Produced for the U.S. Department of Energy (DOE) by the National Renewable Energy Laboratory, a DOE national laboratory.

August 2006 • NREL/SR-550-38783

Printed with a renewable-source ink on paper containing at least 50% wastepaper, including 10% postconsumer waste.

Visit our Web sites at:

www.buildingamerica.gov www.pathnet.org www.energystar.gov

Research Toward Zero Energy Homes