U.S. Department of Energy

Energy Efficiency and Renewable Energy

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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 December 2006 • NREL/SR-550-39744

Building America Residential System Research Results: 

Achieving 30% Whole House Energy Savings in 

Mixed-Humid Climates

January 2006–December 2006

Building America Industrialized Housing 

Partnership (BAIHP)

Cocoa, Florida

Building Industry Research Alliance (BIRA)

Stockton, California

Building Science Consortium (BSC)

Westford, Massachusetts

Consortium for Advanced Residential 

Buildings (CARB) 

Norwalk, Connecticut

Davis Energy Group (DEG)

Davis, California

IBACOS

Pittsburgh, Pennsylvania

National Association of Home Builders 

Research Center (NAHBRC) 

Upper Marlboro, Maryland

National Renewable Energy Laboratory 

(NREL)

Golden, Colorado
Building America Residential System 

Research Results: Achieving 30% 

Whole House Energy Savings in 

Mixed-Humid Climates

January 2006 – December 2006 

Building America Industrialized Housing Partnership (BAIHP) 

Cocoa, Florida 

Building Industry Research Alliance (BIRA) 

Stockton, California 

Building Science Consortium (BSC) 

Westford, Massachusetts 

Consortium for Advanced Residential Buildings (CARB) 

Norwalk, Connecticut 

Davis Energy Group (DEG) 

Davis, California 

IBACOS 

Pittsburgh, Pennsylvania 

National Association of Home Builders Research Center 

(NAHBRC) Upper Marlboro, Maryland 

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-3-32443-10, KAAX-3-33411-10, 

KAAX-3-33412-10, KAAX-3-33410-10

Subcontract Report 

NREL/SR-550-39744 

December 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

This report was prepared as an account of work sponsored by an agency of the United States government. 

Neither the United States government nor any agency thereof, nor any of their employees, makes any 

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

usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not 

infringe privately owned rights. Reference herein to any specific commercial product, process, or service by 

trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, 

recommendation, or favoring by the United States government or any agency thereof. The views and 

opinions of authors expressed herein do not necessarily state or reflect those of the United States 

government or any agency thereof. 

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Table of Contents: 30% Mixed Humid 

Abstract..........................................................................................................................vii 

Executive Summary ...................................................................................................... viii

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

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

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

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

Electronic Reporting of System Research Results .............................................. 9 

Identification of Component Development Needs ................................................ 9 

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

Building America’s Research Goals ........................................................................ 10 

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 Region ................ 22 

Site Development .................................................................................................... 22 

Orientation Impacts ........................................................................................... 22 

Landscaping ...................................................................................................... 23 

Water Management ........................................................................................... 23 

Integrated Design Process ................................................................................ 24 

Energy Analysis ................................................................................................. 28 

Passive Design Strategies for Minimizing Cooling and Optimizing Heating ...... 30 

Indoor Air Quality Strategies............................................................................... 30 

Heating and Cooling Equipment and Distribution Strategies .............................. 36 

i 
First Costs and Cost Tradeoffs .......................................................................... 38 

Water Management ........................................................................................... 42 

Reducing Construction Waste ................................................................................ 42 

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

Value Engineered or “Advanced” Framing ........................................................ 44 

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

Quality Project Management Approach .................................................................. 48 

Operational Evaluation ....................................................................................... 50 

Performance Standards...................................................................................... 51 

Education and Training ...................................................................................... 52 

Verification ......................................................................................................... 55 

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

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

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

Building Component Design Details.............................................................................. 58 

Building Enclosure Integrity .................................................................................... 58 

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

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

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

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

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

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

Space Conditioning and Ventilation Systems ......................................................... 73 

Forced Air .......................................................................................................... 73 

Hydronic ............................................................................................................ 74 

Ventilation .......................................................................................................... 74 

Air Distribution ................................................................................................... 76 

Dehumidification................................................................................................. 79 

Mechanical, Electrical, and Plumbing Systems ....................................................... 80 

Lighting .............................................................................................................. 80 

Major Appliances................................................................................................ 81 

Water Heating and Distribution Systems ........................................................... 81 

ii 
Combination Systems – Space and Water Heating ........................................... 85 

Onsite Power Systems ...................................................................................... 86 

Miscellaneous Electric Loads ............................................................................. 86 

Cost Analysis ............................................................................................................... 86

Life-Cycle Cost Analysis ......................................................................................... 86 

Building Characteristics Considered in this Study .............................................. 86 

Occupancy and Operational Assumptions.......................................................... 87 

Base Case Building ............................................................................................ 87 

Cost Assumptions............................................................................................... 87 

Simulation Limitations......................................................................................... 88 

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

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

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

Community Case Studies............................................................................................ 102 

Longleaf at Callaway.............................................................................................. 102 

Linganore Woods................................................................................................... 107 

Melrose Common................................................................................................... 112 

Frankford Estates................................................................................................... 123 

Grove Park............................................................................................................. 136 

Valencia................................................................................................................. 152 

The Legends at Mansfield...................................................................................... 157 

Appendix A: Passive Solar Design Considerations .................................................... 167 

Appendix B: Detailed BEopt Analysis Results ............................................................ 172 

Appendix C. List of Key Trade-based Certifications ................................................... 178 

Appendix D: National Housing Quality Rating Table .................................................. 183 

Appendix E: High-Performance Scopes of Work......................................................... 201 

Appendix F: Snapshot Form ....................................................................................... 252 

References.................................................................................................................. 253

iii 
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 and Diagnostic Method 

BII Building Industry Institute 

BPI Building Performance Institute 

BPM brushless permanent magnet 

CAD computer-aided design 

CDCU Community Development Corporation of Utah 

CEC California Energy Commission 

CFL compact fluorescent lamps 

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 

iv 
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 

FAU forced air unit 

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 

v 
OA outdoor air 

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 

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 

vi 
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 an 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 systems 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: 

• At a minimum, system energy savings must be achievable at a neutral annual energy-related 

cost relative to the Building America Research Benchmark. 

• 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 Mixed-Humid climate region on a costneutral 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 MixedHumid 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. Near-Term Energy Savings Goals 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 

vii 
Executive Summary 

Background 

Through the use of systems engineering and operations research, the Building America (BA) 

program has shown that homes that save 30% whole-house source energy in Mixed-Humid 

climates can be built by production builders, providing a home with lower annual energy-related 

costs while improving comfort, reliability, durability, and indoor air quality. A series of seven 

case studies are presented in this report, documenting some of the important cost and 

performance trade-offs that were made by BA builder partners in order to achieve the 30% 

energy-savings target in a production context. 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. 

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 an average of 90% by 

2020, 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 near-term targets along the path to 

Zero Energy Homes (ZEH), Building America has specified interim 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 

whole-house energy use by 30% relative to the Benchmark in the Mixed-Humid climate region. 

viii 
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 

Figure ES-1. Building America climate regions 

ix 
To ensure a well-defined reference for evaluation of energy savings and progress toward multiyear goals, a detailed research Benchmark 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 Building America Research Benchmark is a fixed 

reference point that is used to track progress towards multi-year goals and 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 

key results and performance criteria based on several years of Building America research on cost 

effective strategies to reduce whole-house energy use by 30% compared to the Research 

Benchmark in Mixed-Humid climates and provide case studies documenting that the criteria for 

the Building America 30% performance goals in the Mixed-Humid climate have been reached. 

Rainfall in the Mixed-Humid climate region can range from moderate to extreme. In coastal 

areas, the rainwater control measures should follow the Marine climate design, while the 

enclosure design could be less conservative in the interior sections of the climate region. 

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 

x 
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. Detailed check lists are included in Appendix E identifying key 

construction details that are critical to the success of high-performance homes. 

In general, Building America houses at the 30% energy savings level in the Mixed-Humid 

climate region 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 the specific micro-climate within 

the Mixed-Humid climate region, and the level of energy performance the builder is seeking to 

achieve. 

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. It is important that walls be designed with (I) an insulation approach that 

prevents condensing temperatures from occurring inside the wall, (II) an adequate drainage plane 

to allow rain driven by wind through the exterior cladding to quickly drain out of the wall, and 

(III) the right flashing system to ensure that there are no local moisture entry points as a result of 

wall penetrations like windows. Once moisture sources are controlled, then (IV) an appropriate 

vapor-control strategy should be chosen so that excessive vapor transport is reduced, but walls 

have the opportunity to dry if the become wetted. 

Exterior walls in Building America Homes at the 30% performance level in Mixed-Humid 

climates 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 

with insulating sheathing may also be acceptable in parts of the Mixed-Humid climate region 

with fewer heating degree days. In general, insulating sheathing is not necessary to meet the 30% 

savings goal if 2x6 wall construction is used. However, insulating sheathing of sufficient 

thickness and a perm rating of 1 or higher moves the condensation temperature out of the 

framing and allows for the use of vapor-diffusion retarders with a permeability of slightly 

greater than 1 perm, 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. 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 

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

of each. The air leakage target should be less than 0.25 CFM50 (ft3/min at 50 Pa) per square foot 

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 Mixed-Humid 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 if the 

ducts are located elsewhere. 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. When 

possible, raised heel roof trusses should be used so that at least six in. of ceiling insulation is 

maintained completely to the top plates of the exterior wall framing. If there is ductwork in the 

attic space, an unvented, airtight, cathedralized roof construction is recommended to create a 

conditioned attic space for the ductwork. In this way, the mechanical equipment and ductwork 

are located in conditioned space, reducing the energy losses associated with locating the 

mechanical equipment in a vented attic. 

To accomplish the target of 30% whole-house energy savings in the Mixed-Humid 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. This was 

the approach taken for several of the case studies provided. In regions where natural gas is not 

available, a high efficiency electric heat pump is recommended. 

Air conditioners in Mixed-Humid climates should have SEER ratings of 13 or greater, which 

reflects federal minimum efficiency. However, it should be noted that there is a wide range of 

cooling requirements in the Mixed-Humid 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 wet-bulb 

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. 

Ductwork should 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. In some climate 

regions the ducts may be buried in attic insulation, but in the Mixed-Humid climate this is not a 

recommended practice without careful consideration for the possibility of condensation on the 

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

xii 
the type of foundation, and the builder’s preferences. 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. Ducts should be sealed with UL181 mastic for 

metal and flex duct connections, and UL181 foil tape for ductboard to ductboard connections. 

Duct leakage to the outside should be less than 5% of air handler flow at a pressure of 25 Pa. 

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 wholehouse mechanical ventilation system is recommended, such as a balanced system using a heatrecovery ventilator, an exhaust-only system rated for continuous duty, or a supply-only system 

integrated with the central air-handling unit. 

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

dehumidification during the mild swing seasons and at night. Because low sensible heat gain 

reduces the demand for cooling while a latent load still exists, the addition of supplemental 

dehumidification to a high-performance house enables efficient temperature control without 

suffering from high, uncontrolled indoor humidity. In the Mixed-Humid climate region, the need 

for supplemental dehumidification can be more dependent on the homeowner’s habits with the 

thermostat and internal moisture generation. Lowering the thermostat cooling set point tends to 

lower the humidity via the cooling system, whereas elevating the cooling set point tends to 

increase the humidity. 

High efficiency (EF = 0.62) tank-type gas water heaters offer the best value for domestic water 

heating with relatively steady, continuous-use patterns at the 30% performance level. . 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. Primarily because of their cost, tankless gas and solar water heating 

systems are not cost effective at the 30% improvement level. 

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 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 relative to other energy saving options for a house at the 30% 

improvement level. 

xiii 
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 minimal cost, including the utility cost and the cost for energy improvements 

financed as part of a 30-year mortgage. 

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

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

For a house with 30% energy savings, these trends are improved exterior-wall construction, 

crawlspace wall insulation, high-performance glazing, air-sealing measures to reduce infiltration, 

and ducts in conditioned space. For a house at the upper end of the energy savings range (~39%), 

features such as tankless gas water heaters, condensing furnaces, ENERGY STAR appliances, 

and elevated levels of compact fluorescent lighting are commonly added. The results indicate 

that the main drivers for energy and cost savings in Atlanta are heating-load reduction strategies 

(high levels of insulation) coupled with high efficiency space and water heating equipment. Of 

course other considerations, such as durability, comfort, aesthetics, and health, are also 

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

A total of seven case studies demonstrating recommended energy-saving strategies with energy 

savings ranging from 30% to 43% and project sizes ranging from 24 homes to 210 homes are 

included in this report, demonstrating that energy savings of 30% relative to the Building 

America Research Benchmark can be successfully achieved in the Mixed Humid climate. 

xiv 
Table ES-2. Summary of Source Energy Savings by

End-use for the Mixed-Humid Climate Case Studies 

Percent Source Energy Savings 

End Use 

Longleaf, 

Pine 

Mountain, 

Georgia 

Habitat, 

Montgomery 

County, 

Maryland 

Melrose 

Commons, 

Bronx, New 

York 

Frankford 

Estates, 

Baltimore, 

Maryland 

Outlook 

Grove Park, 

Cartersville, 

Georgia 

Ideal Homes, 

Oklahoma 

City, 

Oklahoma 

Legends at 

Mansfield, 

Columbus, 

New Jersey 

Space Heating 39% 75% 50% 51% 52% 38% 53% 

Space Cooling 57% 56% 2% 49% 72% 59% 45% 

DHW 28% 1% 30% 35% 13% 10% 55% 

Lighting -4% 67% 66% 52% -8% 70% 68% 

Appliances + 

MEL 5% 4% 9% 2% 3% 9% 5% 

Total Energy 

Use 

30% 34% 30% 36% 32% 36% 43% 

Number of 

Homes 

30 24 210 78 73 73 39 

xv 

Building America Residential System Research Results:

Achieving 30% Whole House Energy Savings 

in Mixed-Humid Climates 

Introduction 

About Building America 

Purpose 

The Building America Program develops innovative systems-engineering approaches to 

advanced housing that will enable the housing industry in the United States to deliver energyefficient, 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, systemengineering 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 the result 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 systems 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, miscellaneous electric 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 

Community-scale 

Pre-production Houses 

Test 

Build 

Re-design 

Cost and Performance Trade-offs Housing 

Accelerate Development of 

Advanced Energy Systems 

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

with. The development of production-ready results covering the range from 

test houses to community-scale housing takes from 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, 

2 
renewable energy systems, efficient appliances, energy-control systems, and design and 

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. 

Subject to available resources, Building America industry teams continuously evolve and expand 

their membership so that the number of buildings and systems influenced by the program 

continues to show growth 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% 

(which also includes onsite/renewable power solutions) by 2020, relative to the Building 

America Research Benchmark (Hendron 2005),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 cost 

2

 Hereafter in this report referred to as the Benchmark. 

3 
US Homebuilding 

US Wood Products 

US Housing Products 

US (Composite) 

Foreign (Composite) 

Japan (Composite) 

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. 0 1 23 4567 P er cen t age of S al es 

Figure 2. Research and development expenditures3 

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 (2003) for HUD’s Partnership for Advancing 

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

Promoting Innovation in Housing, 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 

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

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 2020 research goal for the program is 

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

4

 In 

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

including the completion of more than 32,000 homes. 

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

combining operations research5 and systems engineering.

6

 The first step of the systems-research 

4

 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. 

5

 Operations Research is research aimed at understanding the how a builder can integrate Systems 

Engineering to maximize building performance, based on the builder’s organizational structure 

and business processes. 

6

 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 
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 

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: Initial CommunityScale Evaluations 

Reports Documenting 

Achievement of Climate 

Performance Goals 

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 

Initiation of Work 

On Next Performance Level 

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. Completion of integrated cost-effective, wholebuilding strategies to enable new, single-family 

residential buildings to use 30% less total energy 

than the Benchmark in the Hot-Dry/Mixed-Dry 

and Cold climate regions. 

4. Documenting research and publishing Houses 

That Work, Builder Guides, and Best Practices 

5. Significant annual increases in 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 

Marine and Mixed-Humid 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, 

Hot-Humid, Hot-Dry/Mixed-Dry, Mixed-Humid, 

and Cold climate regions 

Projected end date(s) 2020 

7 
The systems research is applied in three phases for each climate region. 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. 

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 – Initial Community-Scale 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 region targeted by the program. 

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 systemsresearch 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. 

8 
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 

residential cost/performance studies using analysis methods such as BEopt.

7

 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 a variety of documents and other 

materials from the Phase-3 research reports that are designed for builders, building scientists, 

contractors, manufacturers, homeowners, realtors, educators, insurance companies, and mortgage 

providers. For example, best practice manuals summarize best-practice recommendations in 

7

 BEopt stands for “Building Energy Optimization Analysis Method,” as defined in Anderson et al. 2004. 

9 
illustrated text that are targeted to a specific audience to make them 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 has made floor plans and section details available through its 

website. Other resources developed or supported by BA research include case studies, technical 

publications, software tools, and the Builder’s Guides for various climate regions. 

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). 

Table 3. Building America Research Goals8 

Year 

Characteristics Units 

2007 2010 2015 2018 2020 

Average Source Energy Savings % 30 40 50 70 90 

Cost $ Zero or Positive Net Cash Flow9 

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 

8

 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. 

9

 Life cycle cost (Hendron 2005). 

10 
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. 

30% Whole-House Energy Savings 

Building America’s current research activities target 30% total energy savings in new singlefamily homes in six of the eight climate regions defined by Building America as shown in Figure 

4, including Marine, Hot-Humid, Hot-Dry, 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. 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. 

Because of limited resources, Building America is not targeting the Very Cold and Subarctic 

climate regions because of limited resources and the lack of residential growth as a percentage of 

annual United States housing starts in those regions. 

11 
Figure 4. Building America climate regions 

12 
Ne

w Ho

mes 500,000 

450,000 

400,000 

350,000 

300,000 

250,000 

200,000 

150,000 

100,000 

50,000 

0 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 

Builder Partners 

Mixed Humid Cold Hot Humid Hot/Mixed Dry Marine 

New Homes Builder Partners 

Figure 5. New homes10 and builder partners11 by climate region 

From 2003 to 2005, Building America has developed solutions to use 30% less total source 

energy than the Benchmark for the Mixed-Humid and Marine 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 30% solutions for the Hot-Humid region and 40% solutions for the Hot and Mixed 

Dry regions in 2007. 

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

residential buildings to use 30%-100% less total source 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. 

10 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. 

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

Database, January 5, 2005. 

13 
The purpose of this report is to provide an overview of 3 years of Building America system 

research in the Mixed-Humid climate region that led to the development of homes that save 30% 

relative to the Benchmark.12 Based on the research results and case studies included in this 

report, the Building America industry teams have demonstrated that 30% homes can be reliably 

designed and constructed by production builders in Mixed-Humid 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 energyefficient 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 enclosure 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 Benchmark (Hendron 2005) 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) 

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

14 
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 the 

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

found on the Building America Web site.13 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 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 2003, 2004) or 

Model Energy Code (MEC 1995), 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 monitoring 

(Norton et al 2003) 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. Additional important reference buildings whose 

definitions will vary over the timespan of the Building America Program include State and Local 

Code, regional standard practice, and specific builder standard practice. 

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

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 Building America program. 

EnergyGauge14 is a frequently used interface for DOE-2, tailored specifically to residential 

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

with the IECC performance path. Teams are encouraged to use other simulation tools when 

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

requirements of BESTEST (Judkoff and Neymark 1995) in accordance with the software 

certification sections of the RESNET/HERS Guidelines (RESNET 2002). 

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 (Davis Energy Group 1993), 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 that automate building energy optimization have been recently developed. For 

example, EnergyGauge-Pro

15

 uses successive, incremental optimization (similar to the ACT2 

approach) with calculations based on the “energy code multiplier method” for Florida. GenOpt16 

is a generic optimization program 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 

14 This is available for purchase from the Florida Solar Energy Center (http://energygauge.com/). 

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

(energygauge.com/FlaRes/features/pro.htm). 

16 Wetter, M. “GenOpt®, "Generic Optimization Program,” Seventh International IBPSA Conference, Rio de 

Janeiro, Brazil. (www.ibpsa.org/proceedings/BS2001/BS01_0601_608.pdf). 

16 
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 

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. 

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

17 
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 in 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. 

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. A more accurate energy savings analysis can 

then be performed based on actual instead of theoretical building system performance 

characteristics. 

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 

18 
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 and the interior climate are examples of 

environmental loads that act on houses. 

The recommendations in this research report are applicable to houses constructed in MixedHumid climate regions. 

A Mixed-Humid climate is defined as: 

• A region that receives more than 20 inches (50 cm) of annual precipitation 

• Has 5,400 heating degree days or fewer (65°F basis) 

• Where the average monthly outdoor temperature drops below 45°F (7°C) during the winter 

months. 

The following maps show the approximate outline of areas of the Untied States that are defined 

by the above characteristics, as well as the other climate regions. While the boundary lines have 

been chosen based on the above characteristics, note that being on or near a boundary line 

between climates generally indicates that the principles of either adjoining climate region will 

cover the majority of circumstances under normal siting conditions. 

19 
Figure 7. Climate Region map 

The Mixed-Humid climate region is illustrated in Figure 7. The Mixed-Humid climate region 

covers a narrower range of temperatures, and therefore insulating levels would be more similar 

across the region. The IECC requirements for the different degree day zones give an idea of the 

range of insulation levels necessary, even though they are code minimums. With the goal of 30% 

savings homes, the insulation levels should be increased to minimize energy consumption. 

Rain exposure zones are illustrated in Figure 8. The rainfall variation in the Mixed-Humid 

climate region runs the gamut from moderate to extreme. On the coastal areas of the climate 

region, the enclosure design should follow elements of the Marine climate best practices, while 

the interior sections of the climate region could be less conservative. 

20 
Figure 8. Rainfall total map 

21
Individual locations within the broad general regions and zones described above can vary 

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

local experience, and the micro-climate around a building. Elevation, incident solar radiation, 

nearby water and wetlands, vegetation, and undergrowth can all affect the micro-climate. 

Design Strategy Modification for Variances within a Climate Region 

In general, the approach to rain control (Figure 8) is far more dependent on individual location 

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

insulation do not vary significantly across the Mixed-Humid climate region; however, 

approaches to rain control do. With high rain exposure, the use of a vented rain screen is 

recommended, whereas with lower rain exposure, a drainage plane / drainage space would be 

sufficient. 

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. However, 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 9. For more information about the benefits 

of solar orientation in passive solar design see Appendix A: Passive Solar Design 

Considerations. 

Figure 9. Subdivision site plan for solar orientation17 

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

1981. 

22 
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 Mixed-Humid climate region can help block 

cold north winds, reducing one driving force for air infiltration. Trees, shrubs, and vines not only 

block 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 run 

off. 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. 

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 asphalt or poured 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: Capture storm water from impervious areas to reuse within the 

building. Storm-water harvesting from roofs and hardscapes can be used for non-potable 

uses, such as sewage conveyance, fire suppression, and industrial applications. 

23 
• Storm-water Volume. 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. 

• Buffer Vegetation. Use vegetated buffers around parking lots to remove runoff pollutants, 

such as oil and grit. 

• Water Treatment. 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. 

• Structure Design. 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. 

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 better IDP, builders can incorporate 30% improvement level strategies more 

effectively with less disruption of their normal construction process and do so more cost 

effectively. While use of IDP at 30% improvement level for builders is quite desirable, it will be 

even more important at higher energy performance levels of 40%, 50%, and 70% energy savings. 

24 
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. HVAC designers need to provide input as early as 

possible in the design process, giving feedback to the architect regarding architectural features 

and structural designs that 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 10. 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 

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 energy efficiency, moisture performance, comfort, increased 

durability, and reduced risk. All of these issues are typically addressed by following the 

recommendations included in this report. 

25 
Table 5. Matrix of Trades 

26
-

i

 -

i -

l

i l

i

Product Design 

Process MKTG / ARCH FLOW ARCHITECTURE FLOW MARKETING FLOW PURCHASING FLOW CONSTRUCTION FLOW CONSUL

Marketing determ nes

need for new or refined

product

NO 

Architecture creates Design is tested construction program Architecture begins Spatial layout and 

- structure, schematic design massing focus group or nternally mechanicals, etc. 

Architecture finalizes Schematic HVAC 

with all HVAC schematic design Design Architecture 

vendors Design is evaluated Approved Yes design develo

Consumer Focus Group Develop program for for constructability

on Designs at closeout house size, square

of product Line footage, style Diagrammatic

Structural

Design is reviewed 

for cost 

Preliminary Energy 

evaluation 

Vendor Evaluation 

and Feedback 

Design is evaluated 

relative to program 

determine exact NO

dimensions, Des gn is tested

materials, and code focus group or

compliance interna ly

Architecture finalizes Design Development Design Architecture begins HVAC layout Design is evaluated Approved Yes Construction 10% CD Set 50% CD Set 

for constructability Documentation 

Refine Structural Final Energy 

Modeling, Structural Final HVAC Design R

Design is reviewed & Duct Integration 

for cost 

Energy evaluation 

Vendor Evaluation 

and Feedback 

Des gn is eva uated 

relative to program 

Figure 10.18 Model of the information flows and actions associated with an integrated design pr18 IBACOS, Inc. KAAX-3-33410-06 B.2, Community Scale Process Research Results. Pittsburgh: IBACOS. November 2004. 

27 
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. 

A best practice by some builders participating in the Building America Program 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 a purely energy perspective, the section of this report entitled System Approach to 

Least-Cost Energy Savings 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 systemsdesign 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 

28 
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 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 spaceconditioning 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 region and the level of energy performance the builder seeks to 

achieve. A systems-design approach helps assure that the energy-related aspects of the project 

are being satisfied in conjunction with the non-energy benefits and is done in a way that 

optimizes the synergies of the various systems in the house. 

An important part of getting to the 30% energy savings, or any other level of energy savings, 

is to be able to evaluate alternative combinations of energy features before homes are built. 

Energy-simulation software, also referred to as computer or simulation modeling tools, are 

used to estimate energy performance of buildings quickly and inexpensively long before 

anything is purchased or constructed. Builders can access the costs of the various 

combinations of energy features to determine the most cost effective way of achieving the 

desired energy savings level early in the design process. 

Very often, energy savings of homes only refers to savings of heating and cooling energy, or 

heating, cooling, and water heating. It is important to note that in the 30% savings level 

referenced throughout this report and throughout the Building America Program, references 

are made to whole-house energy savings, including all the energy used in the home for 

heating, cooling, water heating, and all the appliances and miscellaneous electrical loads, 

often referred to as plug loads. 

The other challenge in energy analyses is to be able to compare energy studies done from one 

person to another, in fact from company to company, across the country. For this purpose, the 

Building America program has developed a Benchmark, so that assumptions made in 

conducting energy analyses across the country can be standardized, enabling results to be 

fairly and reasonably compared. 

The Benchmark guidelines are used to define a base-case house for determining levels of 

energy savings in conducting energy analyses. The Benchmark is generally consistent with 

mid-1990s standard practice, as reflected in the Home Energy Rating System (HERS) 

Technical Guidelines (RESNET 2002), with additional definitions that allow the analyst to 

evaluate all residential end-uses, an extension of the traditional HERS rating approach that 

focuses on space conditioning and water heating. A series of user profiles, intended to 

represent the behavior of a “standard” set of occupants, was created for use in conjunction 

with the Benchmark. 

29 
Energy simulations are conducted using software such as Energy Gauge, Energy 10, DOE 2.2, 

TRNSYS and Micropas, to predict the yearly energy consumption in homes.

19

 Energy 

simulations are run for both the Benchmark, as well as the designed home. The design home 

consists of enhanced energy-efficient features and systems. The detailed energy-simulation 

results are used to compute the energy savings of the designed home compared to the 

Benchmark base case. 

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. 

Strategies for passive solar design are discussed in Appendix A. When considering passive 

solar design, one must evaluate the available solar resource. Monthly and annual solar 

resource maps are available from a variety of sources, including 

http://rredc.nrel.gov/solar/old_data/nsrdb/redbook/atlas/ (accessed 08-08-2006). 

Indoor Air Quality Strategies 

The Environmental Protection Agency ranks poor indoor air quality 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 indoor air quality (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 because they 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 droppings, 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 30% improved homes. A number of means of 

source control have been employed: 

• Control entry of water and condensation. 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: 

19DOE’s list of energy simulation software can be found at 

www.eere.energy.gov/buildings/tools_directory/subjects_sub.cfm/pagename_menu=whole_building_analysis 

30 
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 

entitled Envelope Systems discusses climate-specific assemblies. In addition, a builder 

may utilize other regionally specific guidelines, such as the Builders Guides (Lstiburek 

2004). At a more detailed level, static analysis techniques or dynamic models such as 

WUFI20 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 of this report entitled Envelope Systems 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 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 moisture 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 crawlspace 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 large 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 

20 WUFI 2D, Version 2.1. Simulation of heat and moisture transfer. September 2000. 

31 
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 slabon-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-proof coating, masonry capillary-break 

paint, or a layer of poly can be used to isolate the footing from the remainder of 

the assembly. 

• Air-seal the building envelope. 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, this procedure also assists in providing good IAQ for 

the occupant. Extensive air sealing is one of the primary 30% improvement strategies. It 

includes a range of recommendations to builders, including the following: 

o Develop 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 Develop an air barrier with exterior sheathing using taped and caulked joints. 

o Use foam seal (non-expansive) around window and doorframes. 

o Construct well-sealed attic access hatches. 

o Take 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. 

32 
• 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, as 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 Buildings21 

• 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 that do not allow combustion by-products into the house itself. 

o Tank or Tankless Domestic Hot Water (DHW) Heaters. Use sealed-combustion, 

direct-vent, or power-vented types that do not allow combustion by-products into the 

house. 

o Fireplaces. If fireplaces are installed (gas-fired or solid-fuel-burning) are installed, use 

units that directly vent the by-products of combustion to the outdoors, are equipped 

with tight-fitting 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 (i.e., vinyl wall coverings) are all potential sources of indoor air pollutants, 

including various volatile organic compounds (VOCs). Most of the liquid-applied 

materials dissipate potential pollutants rather rapidly as they dry. Leaving windows open 

as they are applied and dry removes the high initial concentrations. After this initial “dryout” 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 

21 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 
needs, then the application of the American Lung Association (ALA) Health House 

Specifications

22

 or specifications to meet the EPA’s Indoor Air Package

23

 would be 

appropriate. 

• Relative Humidity Control. The control of indoor relative humidity (RH) is another key 

strategy to maintain good IAQ. It is recommended that internal RH be maintained below 

60% during periods with high dew points to minimize the potential for condensation and 

growth of mold and mildew. 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), may reduce excess humidity through increased air exchange 

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 another section of 

this report, but key features relative to good IAQ in 30% improvement houses will be noted 

here. 

• Whole-house mechanical ventilation is recommended. Any of a number of system 

configurations can meet this requirement and include the following: 

o Passive inlet direct to the return-air duct with appropriate dampers and controls. In 

northern parts of the Mixed-Humid climate region, total volume of air through the 

passive inlet may need to be limited to keep return air temperatures above 

manufacturers’ lower limits. The balance of ventilation air can be introduced using 

low sone, energy efficient exhaust fans rated for continuous operation. 

o Dedicated supply fans designed for continuous operation are appropriate in the 

southern part of the Mixed-Humid climate region.

o Dedicated exhaust fans designed for continuous operation are appropriate in the 

northern part of the Mixed-Humid climate region. It is recommended that some form 

of whole house air mixing be used with this strategy to ensure appropriate distribution 

of ventilation air throughout the house. 

o HRVs or ERVs 

o Dedicated central dehumidifier with ventilation. 

• Whole-house ventilation air should be distributed to all the primary occupied spaces in the 

house, particularly bedroom and living areas either through direct distribution or by 

mixing or air to maintain uniform conditions within the home. This is typically 

accomplished by ducting ventilation air into the heating/cooling duct system. For this 

22 American Lung Association. Builder Guidelines. American Lung Association® (ALA) Health House®. 

www.healthhouse.org/build/Guidelines.asp October 1, 2004. 

23 Environmental Protection Agency. Indoor Air Package label. Environmental Protection Agency Website. 

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

34 
distribution to be continually effective, however, the HVAC system must be periodically 

cycled, even in periods when no heating or cooling is required. Dedicated ventilation 

distribution ductwork is occasionally used, particularly if no forced-air system exists, 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. 

• 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)24

 of 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. 

• 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. 

• Ventilation technology has developed significantly in recent years, but a few areas remain 

problematic: 

o It is difficult to find low-airflow ventilation units, particularly HRVs and ERVs. 

o 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. 

o Builders do not like the additional cost of installing a ventilation system and often 

have a difficult time explaining why it is needed to the consumer. 

o 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 maintaining good indoor air 

quality in an owner’s manual for the house, including cleaning practices as they relate to 

indoor air quality. 

24 See www.filters-for-home.com/merv.htm for MERV definitions. 

35 
Heating and Cooling Equipment and Distribution Strategies 

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 (ACCA 2003), S (ACCA 1995a), D (ACCA 

1995b), and T (ACCA 1993). 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 with orientation are a 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 as a result 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 of more than 2,500 ft2, two or more units may be needed 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. 

More detailed discussion of heating and cooling equipment selections are given in the section 

of this report entitled Space Conditioning and Ventilation. In the 30% improvement house, 

when natural gas or propane is chosen for heating, the recommendation is to use a sealedcombustion furnace or draft-induced unit with dedicated make-up air so that the combustion 

process is atmospherically decoupled from the house itself and located in conditioned space, 

for efficiency and combustion safety reasons. 

In the Mixed-Humid climate region, 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. In the most southern edge of the Mixed-Humid 

climate (Atlanta or Dallas for instance), if the thermal envelope of the house has been 

significantly improved, the heating load may be dramatically reduced. However, the cost 

effectiveness of a gas furnace and all the associated piping 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. 

It should also be noted that there is a wide range of cooling requirements in the Mixed-Humid 

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. From a design 

36 
standpoint, if the architecture of the home incorporates passive strategies for cooling-load 

reduction (such as shaded south-, west-, and east-facing glass, minimized unshaded westfacing glass, or a design that incorporates low-SHGC glazing and a small number of 

windows) cooling system run hours can be reduced, smaller capacity equipment will be 

appropriate, and SEER ratings as low as 13 may give reasonable performance. In this climate 

region, designers should also recognize that because of the relatively high humidity levels and 

moderate temperatures for much of the year, supplemental dehumidification may be 

necessary. Designers also 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. Builders may also want to consider air conditioning equipment 

with variable speed fans and control strategies that enable higher levels of latent removal at 

low speeds, however this is only effective when cooling is also needed. 

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; in some climate 

regions they may be buried in attic insulation, but in the Mixed-Humid climate region this 

is not a recommended practice without careful consideration for the possibility of 

condensation on the ducts. 

• 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 affects 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 within an insulated “cathedralized” attic 

• Locate in open-web floor trusses 

37 
• 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 entitled 

Space Conditioning and Ventilation Systems. 

Where a boiler or water heater is used for hydronic space heating, a radiant floor or baseboard 

convection distribution system is necessary. These are particularly suited to mixed-humidclimate applications where there may not be a need for air conditioning and the associated 

duct-distribution system. If a radiant floor system is selected in a slab-on-grade installation, it 

is required that 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 they are 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 of this report entitled Space Conditioning and Ventilation Systems. 

First Costs and Cost Tradeoffs 

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. 

Builders who commit to evolving their organizations to the consistent production of quality 

high-performance homes face a transition period. Figure 11 illustrates how the organization 

will typically change through phases and the corresponding change in first costs. 

38 
In

cre

m

e

ntal Construction Costs 

Water Management

In

door Air Quality 

Thermal Enclos

ure 

Impro

vement

Tighten Ducts

Integrated Design 

Full-scale im

plementation 

Transformation Stage 

Figure 11. Incremental Cost versus Transformation Stage curve 

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. 

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 cost effectively. 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 continuingeducation costs built into their overhead structure. 

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 

39 
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 of this 

report entitled Systems 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. 

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’ 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, 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 decrease testing activities, while others have chosen to maintain 100% testing 

as a quality-control measure. In either case, performance testing is a cost that needs to be 

budgeted for. 

Some cost data have been developed from recent Building America 30% improvement level 

projects. 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 houses for one community in Sacramento, California. The case study for this 

project, Premier Gardens, can be found in the report for the 30% Hot-Dry/Mixed-Dry climate 

region (Baechler et al. 2005). 

The cost of the energy efficiency improvements less the cost of the photovoltaic system is 

$3,355, and the monthly and annual utility savings are $38 and $453, respectively. The simple 

payback for these homes will be 7.41 years, or more than $34 per month in positive cash flow 

if the homes are financed with 30-year mortgages at 7% interest. 

40 
Table 6. Illustrative Incremental Costs of a 39% Energy-Saving House in Sacramento, 

ENVELOPE: (Insulation U-Values or R-Values)

Energy Features Benchmark Building 

Energy Features Premier Gardens 

 Roof (attic) R-30 38 (U-value = 0.025) Roof (at furnace) R-30 19 (U-value = 0.047) Wall (Exterior) U-value = 0.076 13+1 inch EPS (U-value = 0.067) (25% Framing factor) Wall (Kneewall) U-value = 0.076 13 (U-value = 0.102) (25% Framing factor) 

Floor (above garage) N/A N/A

 Floor (cantilever) N/A N/A Attic Radiant Barrier No No 

Low Air Infiltration No Yes 

GLAZING: 

Dual Pane Vinyl Frame Windows w/ 

U-Factor Spectrally Selective Glass

 Slider (horz)* 0.673 0.37 Slider (vert)* 0.673 0.37 Fixed* 0.673 0.33 Patio* 0.673 0.34 SHGC Slider (horz)* 0.581 0.32 Slider (vert)* 0.581 0.32 Fixed* 0.581 0.35 Patio* 0.581 0.33 

HVAC SYSTEM:

 Furnace: AFUE 0.78 0.91 

A/C: SEER 10 SEER 14 TXV

 Duct Insulation / Location 5.00 13.0 (buried in insulation) Duct Testing No Yes

 ACCA Manual D No Yes 

WATER HEATING: 

Water Heater Size 40 gal Tankless System

 Energy Factor 0.54 0.82 Distribution Type Standard Pipe Insulation External Wrap R-12 None 

Solar Credit None None 

3rd Party Inspections and Testing (In ComfortWise Program) Yes 

Gas dryer stub Yes Fluorescent lighting (screw-in lamps) Yes, all downlights 2.4kW PV System GE Energy 

Total Estimated Incremental Cost with PV(after rebate) Incremental Cost without PV 

CASH FLOW Total Incremental Cost $10,780.00 

Estimated Monthly Energy Savings $107 Monthly Amortized Cost $72.32 At a 7% interest rate For 30 years 

Net Monthly Savings $34.68 

41 
Water Management 

Many warranty issues are associated with water intrusion; therefore, 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. This issue is more fully discussed in the section entitled Building 

Component Design Details. 

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: 

1. Single-family detached units. Realizing the American dream of owning one’s own 

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. 

2. Home size. In the last 40 years, the median new home size in the United States has 

increased from 1,365 square feet to well over 2,000 square feet, this despite the fact that 

household size has actually decreased by 20%. 

3. Complexity. Not many of today’s homes are simple in form. Jogs, dormers, vaulted 

ceilings, convoluted roof lines, and elaborate staircases abound. 

4. 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 requirements, but has also spawned site practices that simply “throw 

more wood” at the problem. 

5. 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. 

6. 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 sitebuilt, making home building one of the most fragmented of United States industries. 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. 

42 
Two-Foot Module Design 

Starting with foundation layout, the house footprint should be based on 2-ft increments, often 

with significant savings in both 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. The use of a 2-ft grid is illustrated in Figure 12 

for a simple rectangular floor plan. 

-0” 

Figure 12. Two-foot modular approach to framing (drawing courtesy of BSC) 

43 
It is most important that 2-ft increments be maintained for the exterior dimensions to the extent 

possible, including exterior sheathing, ceiling, and foundation perimeters. As a result, the 

drywall dimensions will necessarily be slightly less than the 2-ft increments, and the spacing of 

certain studs and floor joists at edges and corners will be less than 24 in. A more complete 

discussion of the 2-foot modular design approach can be found in the Building Science 

Corporation (BSC) report entitled “Using Wood Efficiently: From Optimizing Design to 

Minimizing the Dumpster.” (Baczek et al 2002). 

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, it saves money and energy over the long term, and it 

improves builder image. 

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®, cited in brackets. 

• Frame 24 in. on center. The prevailing practice among California builders 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. [Table 

R602.3(5).] See Figure 12 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. This “stack-framing” approach 

is illustrated in Figure 13. [Section R602.3.2. A single top plate is listed as an acceptable 

option for in-line framing and with properly tied joints.] 

• 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 nonbearing 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. 

44 
• 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 instead. Using drywall clips also reduces opportunities for drywall cracking and nail 

popping, frequent causes of builder callbacks. Alternative designs for two-stud corners are 

illustrated in Figure 14. [Figure R602.3(2) shows let-in 1x4 bracing in place of sheathing 

and has a note at the bottom of the page for two-stud corners and drywall clips. The figure 

also shows “optimized” cripples (on spacing pattern, with no sill support cripples at the jack 

studs).] 

• Eliminate redundant floor joists. Double floor joists are often installed unnecessarily below 

non-load-bearing partitions. Nailing directly to the subfloor provides adequate attachment 

and support. Partitions parallel to overhead floor or roof framing can be attached to 2x3 or 

2x4 flat blocking. 

• Use 2x3s for partitions. Interior, non-load-bearing partition walls can be framed with 2x3s 

at 24 in. on-center or 2x4 “flat studs” at 16 in. on-center [Section R602.5]. 

45 
Figure 13. Stack-framing approach (drawing courtesy of BSC) 

46 
Figure 14. Two-stud corner framing (drawing courtesy of BSC). 

Figure 15. Integrated framing plan 

A framing plan (Figure 15) can do more than just lay out floor joists. There are opportunities to 

value engineer the floor system and obtain a proper joist count, to ensure all plumbing is 

coordinated with the floor framing, to ensure 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 prior to casting the foundation. 

47 
Recycling of Construction Materials 

No matter how efficient our use of wood there will be some waste—off-cuts 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. Note that 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 translates into 1.1 million acres of clear-cut forest and 30-yard dumpsters lined up endto-end from Phoenix to Chicago! Clearly, builders can achieve and claim significantly 

reduced global and local environmental impact with optimized framing. 

• On-site grinding. If you can grind your waste into wood chips it 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 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. 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 costeffectiveness 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 several performance attributes that any home should provide. 

This definition also establishes the inherent relationship between quality and high performance. 

It is essentially this: while 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 

home builder to truly incorporate a systems approach, he or she must also incorporate a quality 

management approach. 

In order to successfully build high-performance houses in today’s marketplace, builders must be 

willing to make some fundamental changes in their operations. It is evident that those builders 

48 
who have already embarked down the path of operational excellence have the best ability to 

succeed in a competitive market. Once a builder has the operational systems in place to 

efficiently manage all aspects of the design and construction process, then they must look at how 

those operations need to be modified in order to adopt a high-performance approach, which 

includes the following considerations: 

• Operational Evaluation 

• Performance-Based Standards 

• Training/Education 

• Verification 

• Feedback. 

Operationally, builders should be prepared to go through the following steps (listed in order of 

importance) to achieve Building America levels of performance and quality, which are also 

discussed in the section on First Costs and Cost Tradeoffs: 

• Address water management 

• Address indoor air quality 

• Improve thermal enclosure, including air sealing 

• Tighten duct systems 

• Implement integrated design of structure and mechanical systems, bringing ducts inside 

thermal enclosure, right sizing equipment, and applying advanced framing practices. 

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: 

• Operational Evaluation (Modified NHQ25) 

o Paper Review 

o Key Player Interviews 

• Performance-Based Standards 

o Design 

o Specifications 

o Scopes 

• Training/Education 

o For builders 

o For individual trades 

25 The NHQ (National Housing Quality) is the NAHB Research Center’s National Housing Quality Program, 

discussed in detail later in this report. Building America team leader, IBACOS, modified the NHQ system to include 

criteria specific to housing performance. 

49 
o Certifications 

• 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. 

Operational Evaluation 

Modified from the (National Association of Home Builders) NAHB 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, and 

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 the work to be done by 

the builder and sub-contractors. 

• 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 builders 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. 

50 
• 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. Appendix D contains the latest 

version of the modified NHQ two-step process as developed by IBACOS. 

Performance Standards 

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. 

For this purpose, value engineering techniques must be employed to ensure that all the systems 

in the home cannot only be designed 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. 

51 
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. 

Another critical aspect of higher performing houses is the engineering of the mechanical system. 

In order to assure energy efficiency, comfort, and consistency of installation, some builders are 

using a third-party engineering firm to develop a single HVAC system design for a house plan, 

which is then implemented by one or more HVAC installation contractors. Alternately, a design 

build contractor may do the design, but if other companies are installing systems, they must 

follow the design-build contractor’s design. This approach helps ensure quality design and 

allows for more consistent commissioning of systems. 

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 often 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.26 Such specifications could be modified 

and applied to other high-performance home projects. 

Scopes of Work 

Even with careful 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 at EcoVillage, 

IBACOS at Summerset at Frick Park) or detailed installation procedures that could 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 key trades, including 

HVAC and insulation. A sample set of supplemental high-performance scopes of work that build 

on the system put forth in the NAHB BuilderBooks, The Scopes of Work Program (Hass 

Davenport 2000) in key areas impacting Building America construction practices is included in 

Appendix E. 

Education and Training 

Training is 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 

26 Building Science Corporation. 2002. EcoVillage Sample Spec Language. 

www.buildingscience.com/buildingamerica/casestudies/ecovillage/ecovillage.pdf 

52 
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 quality management approaches has typically been builder training. These 

programs 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®27 (EFL) Diamond Class Training. Long-time Building 

America partner, Masco Contractor Services, has developed a new 3-day builder training 

program, a program that 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. 

• National Housing Quality® Consulting and training services for builders and their trade 

partners on the fundamentals of documenting management processes and implementing 

customer-focused quality assurance systems. 

• First Time Quality & Safety for Home Builders®. This service provides training, 

templates, and tools to help builders partner with trade contractors to deliver defect-free 

homes. First Time Quality & Safety emphasizes “build it right the first time” at every stage 

of the construction process. Problems are prevented so production runs faster, safer, and 

more efficiently. 

• 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 

27 Environments for Living is a building-science-based, high-performance home-building program of Masco 

Contractor Services. The program was developed approximately 5 years ago in a public-private partnership with 

Building America. 

53 
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 long 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 three 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 approach. 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 BETC program in California also 

provides training to subcontractors. 

Builder and Trade 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. 

A variety of specialized third-part certification programs for companies / firms are available on 

quality systems and technical services. These certifications are provided by such as groups as the 

North American Technician Excellence (NATE), Building Performance Institute (BPI), and the 

NAHB Research Center (National Housing Quality Certified®). These programs require 

recurring review to maintain certification status. 

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. Certification 

programs can help provide incentives to maintain the discipline of management that is an 

essential ingredient in a viable and effective quality assurance system. These quality assurance 

management systems are resulting in transformations for individual companies and with time the 

influence will be seen industry-wide. A list of key trade-based certifications associated with 

delivery of high-performance housing can be found in Appendix C. 

54 
Verification 

Verification tools for both 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 

• 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 attributes. 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) makes 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 Guides (Baechler et 

al. 2005) produced by Pacific Northwest National Laboratory (PNNL) 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 F. 

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 

55 
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. 

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. 

Because 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 includes these activities: 

• Engaging a commissioning authority and team 

• Documentation 

• Verification procedures, functional performance tests, and validation 

• Training. 

Building commissioning is not one of these: 

• 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. 

56 
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 manufacturers’ claims (and are appropriate 

for the project.) 

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 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, indoor air quality, 

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 highperformance homes. It is a process inherent to systems-thinking and systems-engineering. 

Without the quality management tools to implement the principles of physics and building 

science, higher performance in housing is simply a technical exercise, not a business proposition. 

57 
Building Component Design Details 

Building Enclosure Integrity 

A house is an environmental separator whose function is to separate the inside from the outside 

as required by the local environment and the wishes of its occupants. A house creates an 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: the attic ceiling/roof assembly and the 

foundation slab. 

Fully insulating a basement slab is 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, effective control of heat flow means exterior walls framed with 

2x6 framing where cavities are insulated with fiberglass batts, spray-applied cellulose, or lowdensity 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 in wood frame construction can be accomplished by minimizing the amount 

58 
of framing materials through which conductive heat transfer can occur, increasing the cavity 

thickness to accommodate more thermal insulation, and using 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. 

Increasing cavity thickness to accommodate more thermal insulation can be facilitated in wall 

framing by using 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 with a maximum U-value of 0.35 and SHGC value of 0.4 or lower is recommended. 

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 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 Mixed-Humid climates, interior air-barrier 

systems control the exfiltration of interior, often moisture-laden, air. Whereas exterior air-barrier 

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. Damp 

spray-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. 

59 
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 airbarrier 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 

significant disadvantage of interior air-barrier systems is their inability to control wind washing 

through cavity insulation. 

Installing both interior and exterior air-barrier systems can address the weakness of each. 

The practice of using framing elements in conjunction with the interior gypsum sheathing can 

meet the requirements of a building envelope air-barrier system. In this approach, the primary 

responsibility for reduction of air-leakage openings is shared by both the framer and the gypsumboard 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, noninsulating 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. 

60 
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 

mechanicals intersect 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 

have covers can have removable covers site-manufactured in a similar manner to removable attic 

access covers. 

If these air-sealing strategies are followed, it should not be difficult to achieve a target air 

leakage rate of less than 0.25 CFM50 (ft3/min at 50 Pa) per square foot of thermal envelope area. 

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. Therefore, 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, window and door openings, and 

61 
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 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. 

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 brick 

veneer moisture reservoir from the building. Installing stucco over two layers of building paper 

or over an appropriate capillary break, such as 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, crawlspaces, and basements. 

Concrete and masonry are sponges―they can wick water by capillarity. This is the main reason 

that damp-proofing (the black tar-like coating) is applied to exterior basement walls. The dampproofing 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 (more than 1 

in. thick and 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 crawlspaces. 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. 

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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. 

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 without the creation of “double vapor barriers.” 

• The ability to use damp spray insulations 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 should 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. 

• 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 into the exterior 

enclosure assemblies. 

• Vapor diffusion retarders are not required in a Mixed-Humid climate region as a result of the 

fluctuating seasonal weather conditions, without a dominating drive direction. Flow-through 

wall assemblies that allow drying in either direction are recommended. 

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• 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 40% in the southern Mixed-Humid climate region, 35% in the northern region). 

Controlled mechanical ventilation (dilution with outside air) at the rate recommended by 

ASHRAE 62.2 has been shown to provide sufficient dilution to reduce interior moisture 

below these levels in detached single-family houses. Multi-family units may require higher 

ventilation rates depending on moisture generation. Whole-house humidification is not 

recommended under any circumstances. 

• Allow wet or moist materials used in construction to dry toward the exterior. 

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 Mixed-Humid climates, the primary slab-on-grade approach can involve a 

monolithic slab-grade beam or grade beams poured separately from the slab. Post-tensioning in 

some cases occurs. 

Insulation and Air Infiltration. In Mixed-Humid climates, the perimeter of the concrete must 

be thermally isolated from the ground. This thermal insulation extends from the bottom of the 

grade beam to the top of the slab. A sill gasket also provides an air seal between the foundation 

and the frame structure on top. 

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 monolithic slab-grade beam assemblies, the entire concrete assembly must be 

isolated from the ground with a capillary break. This involves installing a polyethylene sheet 

membrane under the grade beam extending to grade. The exposed portion of the foundation 

above grade is damp-proofed using latex paint. 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 – a sand layer should never be 

installed between the polyethylene sheet membrane and the concrete slab. 

Interaction with Mechanical Systems. Passive sub-slab ventilation is recommended to reduce 

atmospheric air pressure soil gas drivers. 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, direct-vent, or power-vented 

appliances that do not allow combustion by-products into the house should be installed within 

the pressure boundary of the building enclosure. 

64 
Crawl Space 

Structure. In Mixed-Humid climates the recommended crawl space approach involves 

conditioned crawl space construction. Vented crawlspaces are energy inefficient compared to 

conditioned crawl spaces when ducts are present, and interfere with ground coupling where the 

ground can act as a heat sink during air conditioning. 

Insulation and Air Infiltration. The perimeter wall of crawl spaces must be insulated. Interior 

rigid insulation is the insulation system of choice because it is not water sensitive. The assembly 

must be fire rated. The interior location is preferred from both a constructability perspective and 

insect-resistance perspective. 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 continuoussealed 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, direct-vent, or power-vented 

appliances that do not allow combustion by-products into the house 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 Mixed-Humid climates the recommended basement approach involves insulating 

and conditioning the basement. Un-insulated, unconditioned basements are energy inefficient 

compared to insulated conditioned basements and interfere with ground coupling where the 

ground can act as a heat sink during air conditioning. 

Insulation and Air Infiltration. The perimeter wall of basements must be insulated. Interior 

rigid insulation is the insulation system of choice because it is not water sensitive. The assembly 

needs to be fire rated. The interior location is preferred from both a constructability perspective 

and insect-resistance perspective. 

The thermal insulation would ideally extend from the top of the footing to the underside of the 

floor framing to complete the thermal envelope, but an alternate option is use upper half height 

insulation with consideration for the overall energy consumption of the home versus budget 

constraints. Upper half height insulation covers most of the heat loss from basement walls, in 

that it covers the area that fluctuates most seasonally, while the lower half sees more constant 

65 
temperatures. Full wall insulation kept 6 in. off the basement floor has also been successfully 

implemented in some projects. In any of these cases, 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 continuoussealed air barrier and vapor-barrier ground cover should be installed. If the interior basement 

floor elevation 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, direct-vent, or power-vented 

appliances that do not allow combustion by-products into the house 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 basement 

should be accomplished by supplying conditioned air to the basement either via a dedicated duct 

or via transfer air from the house where a continuously operating exhaust fan is used as the 

pressure driver. 

Building Enclosure Integration Strategies 

Walls 

The function of wall systems is to provide environmental separation between the interior and 

exterior, transfer wind and seismic loads to the foundation, and 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 Mixed-Humid climates, the primary structural approach is site-built wood-frameutilizing engineered elements, including 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 approach 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. Whereas 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 following are the principle means of controlling lateral loads: 

• Metal cross braces 

• Wood “let-in” braces 

• Structural sheathing such as plywood or OSB 

• Proprietary shear panels. 

66 
Insulation and Air Infiltration. The optimum approach to insulation involves 2x6 advanced 

frame walls with insulating sheathing replacing OSB or plywood sheathing. Other strategies 

include 2 x 6 framing with OSB or plywood sheathing, or 2x4 framing with insulating sheathing. 

Cavity insulation is either unfaced fiberglass batt insulation, dry installed or damp sprayed 

fiberous insulation, or spray applied foams. 

Air-infiltration control is provided by an air barrier. An interior air barrier is used, specifically 

the interior gypsum sheathing combined with using framing elements, such as draft-stopping and 

fire-stopping components. 

Water Management, Drainage, Vapor Diffusion. Rainwater management is provided by using 

a weather resistive barrier (housewrap, tar paper, etc.) as a drainage plane and integrating 

windows and doors with the weather resistive barrier to provide drainage plane continuity. 

Vapor diffusion is allowable in a Mixed-Humid climate as a result of the fluctuating seasonal 

conditions. Therefore, no specific vapor diffusion control techniques are required. 

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, direct-vent, or power-vented appliances that do not allow combustion by-products 

into the house should be installed within the pressure boundary of the building enclosure. 

Windows 

Proper use and selection of windows can make a tremendous difference in the desirability, 

usefulness, and energy consumption of interior spaces. Unfortunately, the introduction of holes 

through the building enclosure in the form of windows brings about challenges both from space 

conditioning energy and water management perspective. Wall insulation levels are often 5-10 

times higher than that of windows, and walls prevent direct radiant heat gain. On the other hand, 

windows provide lighting, beneficial solar heat gain during heating seasons and the opportunity 

for natural ventilation, three significant energy advantages. 

Window U-values are recommended to be 0.40 or lower in the Mixed-Humid climate region. 

However, with the current window marketplace, low-e, double-pane windows can readily 

achieve a U-value of 0.35 with minimal additional cost. 

The 2004 Supplement to the 2003 International Residential Code (IECC 2003, 2004) requires a 

SHGC of 0.40 in the Hot-Dry, Mixed-Dry, Marine, Hot-Humid, and southern parts of the MixedHumid climate regions. Relatively low (0.30) SHGC glazing has been used successfully in 30% 

improvement homes in all climate regions. 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. Therefore to minimize overall energy 

consumption, it is simplest to use windows that prevent radiant, conductive, and convective heat 

flow. The following are the reasons for this: 

67 
• Traditional production-builder house models are oriented in any direction. Using lower 

SHGC glazing in all windows assures an overall reduction of the heat gain during the cooling 

season, regardless of how the house is placed with respect to the sun. This reduction in heat 

gain reduces the load on the air conditioning system. 

• 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 airflow rates and, therefore, require smaller ducts. Lower airflow rates also 

require smaller fans, which use less electricity to operate. Reducing the size of the airconditioning (AC) system also means cost savings to the builder, which can be reinvested in 

other energy upgrades. 

• Use of lower 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. 

However, it should be noted that two Building America production home builders have 

expressed a willingness to experiment with using higher SHGC for south-oriented windows as 

part of BA research. 

Windows and window openings also tend to be the source of most water intrusion problems in 

buildings. Therefore, the water management details of proper window installation are critical for 

the long-term durability of the building. Energy efficient buildings that have moisture problems 

and need to be renovated or fixed in the short term are significant energy and material wasters. 

Providing pan flashing under windows and properly tying the window into the drainage plane are 

of the utmost importance to keeping water out of the walls that surround the windows. 

Floors 

The function of floor systems is to provide environmental separation between the interior and 

exterior where they intersect the exterior enclosure, to transfer wind and seismic loads to the 

foundation by functioning as a diaphragm, and to transfer loads from the floor to the vertical load 

bearing assemblies, which then transfer the loads to the foundation. As part of the provision for 

environmental separation, floor systems have to control heat flow, airflow, rainwater, and watervapor flow. 

Structure. In Mixed-Humid 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 spray foam 

insulation on the interior of the rim joist assembly. 

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 

a weather resistive barrier 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. 

68 
Vapor diffusion is addressed and allowed by installing vapor retarders as opposed to installing 

vapor barriers on the interior or exterior of assemblies constructed in Mixed-Humid climates. 

Interaction with Mechanical Systems. The tighter the building enclosure, the greater the 

pressure differential created with exhaust appliances. The use of an air-barrier rim-joist assembly 

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, direct-vent, or power-vented appliances that do not allow combustion by-products 

into the house should be installed within the pressure boundary of the building enclosure. 

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 vertical load bearing assemblies. 

As part of the provision for environmental separation, roof/attic systems have to control heat 

flow, airflow, rainwater, and water vapor flow. 

Structure. In Mixed-Humid 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. 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. 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 draftstopped, ceiling light fixtures are 

selected to be airtight, and all penetrations through plates are air sealed. 

If there is ductwork planned for the attic space in a Mixed-Humid climate, two strategies may be 

used. One is an unvented, conditioned attic construction that would be recommended in place of 

insulation blown on top of the ceiling gypsum board. The mechanical equipment and ductwork 

are then located in the conditioned space, reducing the energy losses due to locating the 

mechanical equipment in a vented attic. Alternatively, the top surface of the ceiling gypsum 

board may be insulated in a vented attic with well insulated, sealed ducts above the insulation. 

With this approach, the total HVAC system leakage (air handler and duct distribution system) to 

outside should be less than 5% of air handler flow, and the insulation level on the ducts should 

be a minimum of R-8. 

Water Management, Drainage, Vapor Diffusion. Traditional roofing materials, such as 

shingles, are used to provide rainwater management at the roof deck. 

In the case of a vented attic, vapor diffusion is handled by providing passive or active roof/attic 

ventilation and by not installing an interior vapor barrier. In the case of an unvented attic, vapor 

diffusion is accommodated by not installing a vapor barrier on the interior, and the duct system 

69 
provides conditioned air. 

Figures 16 and 17 are examples of building envelope details for recommended Mixed Humid 

crawl space and basement assemblies. 

Interaction with Mechanical Systems. 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, direct-vent, or power-vented 

appliances that do not allow combustion by-products into the house should be installed within 

the pressure boundary of the building enclosure. 

70 
Figure 16. Mixed-Humid: recommended wall section for crawlspace foundation 

71 
Figure 17. Mixed-Humid: recommended wall section for basement foundation 

72 
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 U.S. census data, 91% of the houses constructed in the northern part 

and 100% of the houses constructed in the southern part of the Mixed-Humid climate region in 

2005 had central electric air conditioning. Central natural gas-fired furnaces were used in 88% 

(northern Mixed-Humid climate region) and 47% (southern Mixed-Humid climate region) of 

newly constructed houses in 2005. 

To accomplish the target of 30% whole-house energy savings in the Mixed-Humid 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 several of the case studies provided. In areas where natural gas is not available, a high 

efficiency electric heat pump is recommended. 

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 cause cold draft complaints 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.28 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 

28Hedrick, R., Home Builders Guide to Ducts in the Conditioned Space, www.energy.ca.gov/reports/2003-11­

17_500-03-082_A-16.PDF 

73 
and/or soffits should be considered first.29

 Alternatively, Building America teams have also 

employed unvented attics and modified roof trusses. 

With the high-performance envelope measures described in previous sections, the annual cooling 

load for homes in the Mixed-Humid climate region is less severe than it is in warmer climate 

regions, but it is still substantial. Air-conditioning systems with efficiencies at the new 

NAECA30 minimum efficiency of SEER 13 are usually sufficient. However, the availability of 

incentives for higher efficiency equipment and/or the specific design and loads of the home 

could make even higher efficiency equipment an appropriate consideration. 

Selecting an efficient air conditioner is only part of the story. Right sizing of air conditioners 

(using ACCA Manuals J and S [ACCA1995a, 2003]) will minimize operating efficiency losses 

resulting from cycling. Air conditioners and matching evaporator coils should be selected that 

have a sensible cooling capacity that meets or slightly exceeds the sensible cooling load from 

Manual J. Proper installation is required to ensure that air conditioners perform to their rated 

efficiencies. Improper refrigerant charge can significantly compromise air-conditioner efficiency. 

Thermostat expansion valves (TXVs), which dynamically adjust refrigerant flow, can 

compensate for improper charge and should be used instead of orifice-type expansion devices. 

Furnaces or air handlers with “variable-speed” BPM DC motors (sometimes called electronically 

commutated motors, or ECMs) are recommended (Pigg 2003). 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. 

Hydronic 

Where air conditioning is not installed initially, as is often the case for affordable housing, or 

where 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. Nevertheless, when system 

performance is considered, including the hydronic distribution system and the use of the boiler to 

supply domestic hot water needs as well, a high efficiency (85%-87% AFUE) non-condensing 

boiler with a power vent or direct vent may be the optimum choice. 

The use of domestic 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-ource 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 

29 McIlvaine, Beal, and Fairey. Design and Construction of Interior Duct Systems. 

www.fsec.ucf.edu/bldg/baihp//pubs/interior_ducts.pdf. 

30 NAECA refers to the National Appliance Energy Conservation Act established in 1987. 

74 
specifications of ASHRAE Standard 62.231

 is recommended. For Mixed-Humid climate homes, 

there are several approaches with varying levels of initial cost and complexity (DOE 2002). The 

following systems may be appropriate: 

• a balanced system using an energy-recovery ventilator 

• an exhaust-only system low-sone bath fan rated for continuous duty 

• a supply-only system integrated with the central air-handling unit. 

Each system has different features and benefits, and there is no clear “best” approach that applies 

for all builders and homebuyers in the Mixed-Humid climate. 

Balanced heat- or enthalpy-recovery systems have the advantages of transferring heat and 

moisture between the incoming and outgoing airstreams, 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, 3,000-ft2 home). Homeowners need to 

understand the operation and importance of proper maintenance for these systems to perform 

properly. 

It has been demonstrated in the northern section of the Mixed-Humid climate region that 

exhaust-only systems are the lowest in initial cost and simplest to implement.32 However, the 

outside air enters the home unfiltered and through unknown locations. The circulation of the 

ventilation air throughout the home is also dependent 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. With adequate control of winter 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. 

A central fan integrated ventilation system (“fan-cycling”) provides supply ventilation and 

whole-house mixing with minimal additional cost to the builder. An outdoor air duct with 

integral motorized damper is connected to the return side of the air handler and a controller 

operates the motorized damper and central fan intermittently to provide adequate ventilation by 

drawing in a percentage of outdoor air as the central fan re-circulates the indoor air. It is 

important to note that some manufacturers have warranty limitations on low return-air 

temperatures. The volume of outdoor air brought in and corresponding mixed return-air 

temperature at winter design conditions should be evaluated to make certain it will be within 

acceptable limits. As with all mechanical systems, it is also important that the system is properly 

commissioned.33 Two factors that must be considered for this type of ventilation system are the 

31 ANSI/ASHRAE 62.2-2004, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings. 

32 Furnace Fan Penalty, Energy Design Update, June 2005. 

33 BSC. 2004. Ventilation System Installation and Commissioning Guide. 6 pp; Record No. 35395. Building 

America Web site document database: 

www.eere.energy.gov/buildings/building_america/pdfs/db/35395.pdf#search=%22Ventilation%20System%20Install 

ation%20and%20Commissioning%20Guide%22 

75 
electricity used to drive the central fan, and the challenge of obtaining the desired ventilation rate 

through a passive outside air duct. 

As with all mechanical systems, it is important that ventilation systems be properly 

commissioned. Commissioning should include verification of fan operation and control settings 

and measurement of the outside air volume. 

Air Distribution 

For the 30% energy-savings level, a number of recommendations apply to the 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 

• 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, but this practice should be 

minimized to the greatest extent possible. 

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 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 slab 

on grade construction. 

While the distribution system is important from an energy perspective, there are also health, 

safety, and indoor air quality issues to be considered. The following sections briefly discuss 

each, with recommended solutions. 

76 
Sealed Forced-Air Distribution Systems 

Leaky duct systems located outside the conditioned space, in addition to the energy losses 

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-approved mastic is the only acceptable sealing 

method; for duct board, UL 181 tapes are accepted; and for flex duct, a combination of UL 181­

approved mastic and strap ties should be used. The target for total duct leakage to the outside 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 forcedair 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-approved 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 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 “jump ducts,” or transfer grills located in the walls. Door under cuts 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 U-value and SHGC, and air sealing have been improved 

77 
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 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 cooling-dominated climates, it has been typical to locate supply registers in the ceiling. This 

works well for cooling, but may present problems during heating periods. High sidewall and 

ceiling register placements have been used successfully in Building America projects. To attain 

optimal performance and comfort, 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 airflow 

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 that 12 to13 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. 

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, heating/cooling variation 

• Impact of zoning systems 

• Solar load variability 

• Buoyancy issues 

• Sound issues 

• Register/nozzle configurations 

78 
• 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. In the Mixed-Humid climate, if ducts must be run in 

attics, it is not generally recommended to bury ducts under attic insulation without careful 

consideration for the possibility of condensation. Condensation can form on the outside of the 

duct vapor barrier and cause moisture problems in the home when buried under additional attic 

insulation. Similarly, it is critical to make sure all metal fittings are well insulated to avoid 

condensation. 

Dehumidification 

Controlling indoor moisture will consume more energy than not controlling it. However, 

providing efficient means to limit indoor relative humidity enables other improvement measures 

that exceed the cost of dehumidification. For example, reducing sensible heat loads by using low 

solar heat gain windows and getting ducts out of hot attics reduces cooling energy consumption 

more than the increased energy consumption of supplemental dehumidification. Dehumidifying 

interior conditioned spaces will consume energy but the benefits of indoor air quality, comfort, 

and durability are clear. As homes become more energy efficient, they should also be 

comfortable, safe, and durable, which will ultimately sell more energy efficient homes. 

Especially for high-performance, low sensible heat gain homes, the need for supplemental 

dehumidification begins to become obvious in the mild swing seasons and at night. Low sensible 

heat gain reduces demand for cooling while a latent load still exists. The addition of 

supplemental dehumidification to the high-performance house enables the energy savings of 

efficiency improvements that significantly reduce cooling demand without suffering from high, 

uncontrolled indoor humidity. The addition of ventilation to standard houses in humid climates 

produces a slight upward trend in indoor humidity, but differences in occupant behavior can have 

a larger impact. Internal heat and moisture generation, thermostat set points, thermostat setup and 

manual thermostat on/off control seem to have the greatest effect.

34 

Use of supplemental dehumidification could be considered a necessity in some climates (hot 

humid), but in the Mixed-Humid climate region the need for supplemental dehumidification can 

be more dependent on homeowners’ habits with the thermostat and internal moisture generation. 

Lowering the thermostat cooling set point tends to lower the humidity via the cooling system, 

whereas elevating the cooling set point tends to increase the humidity. Also, a house with high 

internal moisture loads will experience heightened humidity, if not for supplemental 

dehumidification. 

34 Rudd, A and H. Henderson. 2005. Monitored Indoor Moisture and Temperature Conditions in Humid Climate 

U.S. Residences, BSC Deliverable KAAX-3-32443-08.B.2. 

79 
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 

compact fluorescent lamps (CFLs) 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. In addition, fluorescent lamps give off less heat than their incandescent counterparts, 

thereby lowering internal gains and making homeowners feel more comfortable during cooling 

conditions. 

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 National Laboratory, 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 that show great promise but need further refinement and fieldtesting: 

• 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 

80 
• Evaluation of energy-savings potential from incandescent dimming. 

Residential lighting controls represent 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 because of increased demand for commercial 

applications, they have 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 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 energyefficient 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 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. 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. 

While not a mechanism for direct source energy reduction, peak-load shifting is a beneficial 

strategy from a consumer-utility cost perspective where time of use rates are in effect 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 offpeak hours and refraining or minimizing their use, especially simultaneous use, during peak 

hours. 

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 when ever 

practical.

35 

Water Heating and Distribution Systems 

At the 30% improvement level, energy use for water heating becomes a significant component of 

total energy use. Consequently, the following guidance has been developed for the design and 

installation of DHW Systems: 

35 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. 

81 
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 below, 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 procedure for sizing tank-type domestic hot water heaters. 

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 region where the house is located 

(Figure 18) 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. 

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 vent with dedicated outside air for combustion, or sealed-combustion units that 

draw combustion air from outdoors and fan discharge combustion gases outdoors. If electricity is 

Figure 18. Domestic hot water tank sizing for 135°F tank temperature only 

82 
used for heating water, a high-efficiency tank with an EF of greater than 0.90, or a tankless unit 

could be used. Electric tankless units typically require 240 volts, 60 – 100 amp service, and can 

induce a significant electric peak load when operating, which may be costly for consumers if 

they are in a utility service territory that has demand charges or time-of-use rates based on peak 

power pricing. 

Gas-fired 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 to 20 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 are 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. 

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 the Mixed-Humid climate, especially the southern sections 

of this climate region. 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 if 

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 

pricing varies dramatically by region and can be more complex than a traditional gas furnace 

with DX air-conditioning systems or electric heat pump systems. In an area where no natural gas 

83 
is available, a ground-source heat pump system is an option in all climate regions; however, it 

requires a skilled and experienced installer base and favorable pricing. 

While not 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 thermosiphon/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 a simple set of 

characteristics, such as a long pipe run from the collector plate combined with a short, infrequent 

usage pattern, can render the solar contribution 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 hot water 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 laundry that are back-to-back. Short lines will 

minimize “stranded” losses, which can be considered detrimental during the cooling season. 

Locating tankless water heaters immediately adjacent to high-use clusters, such as a pair of 

bathrooms in a remote wing or a second floor, is an excellent way 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. 

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 high loss 

of heat from the piping system, even if insulated, and is strongly discouraged in an energyefficient house of any type. 

84 
If a recirculation system must be installed, a push-button type on-demand re-circulator will 

minimize the energy penalty associated with recirculation systems. The system circulates the 

water only when the hot water is needed. It is, thus, more energy efficient than the continuous 

recirculation system. The on-demand circulating pump briefly moves water out of the hot water 

pipe and back to the DHW heater down the cold water pipe until hot water is sensed at the 

faucet. This system greatly reduces the waste of water down the drain. 

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 refers 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 high efficiency gas-fired boiler serving hydronic baseboard units for space heating and an 

indirect storage tank for domestic hot water. Air conditioning, if needed, would be provided 

by a separate system. 

• 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 combination boiler which provides hot water for space heating as well as domestic hot 

water via a separate heat exchanger 

• 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 as follows: 

• 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, and further improvements 

can be provided by removing the tank losses entirely with a tankless, on-demand system. 

An important factor to success for all of these systems, is that the plumbing and HVAC 

contractors 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 

when 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, thus making these systems suitable 

for many houses in the Mixed-Humid climate region. Also, careful design and attention to detail 

is necessary for proper operation of these systems.

36

 Thermo-siphoning during summer airconditioning 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 

36 Combo Space/Water Heating Systems – “Duo Diligence”, Building Science Corporation. 

85 
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 improvements to the 

envelope; the heating, cooling, and domestic hot water systems; and possibly the lighting and 

appliance. On-site power systems are very costly and are not recommended as a strategy to 

achieve the 30% savings level. 

Miscellaneous Electric Loads 

In the Mixed-Humid climate region, miscellaneous electric loads can account for approximately 

22% up to 30% of the total energy consumption of the house. This load category includes all of 

the power used for the “stuff” homeowners typically have in their houses – anything that plugs 

into a wall outlet. There are strategies to reduce these loads, such as using plug strips to turn off 

devices with power draws like computers and entertainment equipment when not in use, however 

at this point these strategies are not something the builder is likely to install as part of the 

construction of the home. At the 30% energy-savings level, it is not required to address specific 

strategies for energy efficiency in this load group, however at higher energy-savings levels 

(50% +) lowering the energy consumption of miscellaneous electric loads will be a critical 

strategy. 

Cost Analysis 

Life-Cycle Cost Analysis 

From a purely economic point of view, building energy optimization involves finding the global 

optimum that balances life-cycle cost versus utility-bill savings. Given a particular energysavings 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 in Atlanta, Georgia, which was chosen as a representative city in the MixedHumid climate region. 

Building Characteristics Considered in this Study 

For the Prototype building, a two-story 3,000-ft2 and a single-story 1,500-ft2 residential building 

were used for this study with the front of the buildings facing east. Although complex floor-plan 

86 
geometries can be analyzed, a simple square floor plan was implemented for the purposes of the 

current analysis. The buildings were modeled with an unvented crawlspace foundation. Both 

buildings were assumed to have three bedrooms and two bathrooms. The building was assumed 

to have 1-ft eaves. Window area was 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 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 were assumed to use natural gas for the 

following end uses: cooking, space and water heating, and clothes drying. Air-conditioner 

capacities less than 1.5 tons were not considered, nor were furnace capacities less than 50 

kBtu/hr. SEER-10 air-conditioners were not included in this analysis because federal minimum 

equipment efficiencies mandate the manufacture of air conditioners with a minimum SEER-13. 

No options that would potentially reduce miscellaneous electric loads other than major 

appliances were included in the study. Also, no options were included that would result in a 

house that could not comply with the prescriptive compliance path of the 2006 International 

Energy Conservation Code (IECC). 

Occupancy/Operational Assumptions 

Occupancy and operational assumptions are as defined in the Benchmark and include time-ofday profiles for occupancy, appliances, MELs, 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, Uvalues, 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 energyoption 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. Means (1999) 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. 

87 
The mortgage interest rate is 5% above the rate of inflation, which is assumed to be 3%. The 

onsite power option used for this study is 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 are not considered. For Atlanta, natural gas is assumed to cost $1.023/Therm, and the 

cost of electricity is modeled as $0.0632/kWh. These values are based on the data published by 

EIA for the month of May 2006. 

Simulation Limitations 

Some benefits not considered by the BEopt analysis method will have an influence on the realworld design of a home, such as reduction in warranty 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 retraining trades to implement 

Building America strategies, 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. 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 Atlanta TMY237

 weather file. Figure 19 shows the 30% 

whole-house energy savings point that falls on the cost-optimal curve for Atlanta. 

37 Typical Meteorological Year weather data, http://rredc.nrel.gov/solar/old_data/nsrdb/tmy2/ 

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 19 would 

represent a possible least-cost combination for 30% whole-house energy savings for a singlestory residence in Atlanta. Because costs may vary significantly across the Mixed-Humid climate 

region, from builder to builder, and over time, this example may not reflect the actual least-cost 

set of options that would apply to a specific home, builder, and location. 

Figure 19. The 30% point for a single-story Atlanta example case 

The results suggest that high-performance windows, ducts in conditioned space, and a small 

amount of fluorescent lighting is sufficient to achieve the 30% energy-savings target in Atlanta. 

At the other end of the building energy performance range considered here, 39% whole-house 

energy savings, the first cost is slightly higher than the 30% example, but the total energy-related 

cost is lower. Figure 20 shows an example combination that meets 39% whole-house energy 

savings compared to the 30% combination. 

89 
Figure 20.

38

 Comparison of 39% point to the 30% point, one-story Atlanta 

example case 

The comparison of the 30% combination (represented in magenta) to the 39% combination (blue 

only) shown in Figure 20 demonstrates that by utilizing additional ceiling insulation, more 

fluorescent lighting, a condensing furnace, and a tankless gas water heater, the 39% energy 

savings level can be achieved at a lower total cost per month than the 30% single-story example. 

Figure 21 and Figure 22 look at the same energy-performance levels for the two-story case. 

The comparison of the 30% combination (represented in magenta) to the 39% combination (blue 

only) shown in Figure 22 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 30% and 39% example cases. 

38 Note that cost show in this figure are incremental relative to the 30% energy savings point (shown in magenta) 

90 
Figure 21. The 30% point for the two-story Atlanta example case 

91
Figure 22.

39

 Comparison of the 39% point to the 30% point, two-story 

Atlanta example case 

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 30% and 39% energy-savings level are limited to window type, 

dishwasher efficiency, and duct location. 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. 

39 Note that costs shown are incremental relative to the 30% energy-savings point. 

92 
Table 7. Comparison of Single- and Two-Story Cases in Atlanta 

CATEGORY 30% EXAMPLE 39% EXAMPLE 

Number of 

Floors 

One Story Two Stories One Story Two Stories 

Walls R-19, 2x6, 24 in. oc R-19, 2x6, 24 in. oc R-19, 2x6, 24 in. oc R-19, 2x6, 24 in. oc 

Ceiling R-30 FG R-30 FG R-40 FG R-30 FG 

Thermal 

Mass 

1⁄2-in. Ceiling Drywall 1⁄2-in. Ceiling Drywall 1⁄2-in. Ceiling Drywall 1⁄2-in. Ceiling Drywall 

Infiltration SLA = 0.0003 SLA = 0.0003 SLA = 0.0003 SLA = 0.0003 

Crawlspace Unvented, R-11 interior 

insulation 

Unvented, R-11 

interior insulation 

Unvented, R-11 interior 

insulation 

Unvented, R-11 interior 

insulation 

Glass Type 

Two-pane, Low-e, 

spectrally selective, 

U = 0.30, SHGC = 

0.34, vinyl frame 

Two-pane, Low-e with 

tint, U = 0.31, 

SHGC = 0.29, 

vinyl frame 

Two-pane, Low-e, 

spectrally selective, 

U = 0.30, SHGC = 0.34, 

vinyl frame 

Two-pane, Low-e, 

spectrally selective, 

U = 0.30, SHGC = 

0.34, vinyl frame 

Window 

Area per 

Wall 

270 ft2

, 12.5% N&S, 

50% W, 25% E 

540 ft2, 12.5% N&S, 

50% W, 25% E 

270 ft2, 12.5% N&S, 

50% W, 25% E 

540 ft2, 12.5% N&S, 

50% W, 25% E 

Refrigerator Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr 

Cooking 

Range 

45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 

Dishwasher 

Clothes 

Dryer 

Clothes 

Washer 

Standard, 462 kWh, 

eight place setting 

capacity, 131.6 kWh/yr 

machine energy, 

5.39 gal/day DHW 

Gas - 5.7 ft3

, 2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Standard, 3.15 ft3 , 

533 kWh/yr, 1.16 MEF, 

65.6 kWh/yr machine 

energy, 4.63 gal/day 

DHW 

Standard, 462 kWh, 

eight place setting 

capacity, 131.6 kWh/yr 

machine energy, 

5.39 gal/day DHW 

Gas - 5.7 ft3

, 2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Standard, 3.15 ft3 

, 

533 kWh/yr, 1.16 MEF, 

65.6 kWh/yr machine 

energy, 

4.63 gal/day DHW 

Standard, 462 kWh, eight 

place setting capacity, 

131.6 kWh/yr machine 

energy, 5.39 gal/day DHW 

Gas - 5.7 ft3

, 2.75 EF, 

70.1kWh/yr, 

31.8 therms/yr 

Standard, 3.15 ft3 

, 

533 kWh/yr, 1.16 MEF, 

65.6 kWh/yr machine 

energy, 

4.63 gal/day DHW 

ENERGY STAR, 

384 kWh, eight place 

setting capacity, 82.2 

kWh/yr machine 

energy, 

3.76 gal/day DHW 

Gas - 5.7 ft3

, 2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Standard, 3.15 ft3 

, 

533 kWh/yr, 1.16 MEF, 

65.6 kWh/yr machine 

energy, 

4.63 gal/day DHW 

Lighting 20% CFL, 877 kWh/yr 

hard-wired, 331 plug in 

0% CFL, 2634 kWh/yr 

hard-wired, 571 plug in 

40% CFL, 643 kWh/yr 

hard-wired, 331 plug in 

20% CFL, 1380 kWh/yr 

hard-wired, 571 Plug in 

Air 

Conditioner 

SEER 13, 1.5 tons, 

0.364 W/CFM AH Fan 

SEER 13, 2.5 tons, 

0.364 W/CFM AH Fan 

SEER 13, 1.5 tons, 

0.364 W/CFM AH Fan 

SEER 13, 2.5 tons, 

0.364 W/CFM AH Fan 

Furnace 80% AFUE, 30 kBtu/hr 92.5% AFUE, 

50 kBtu/hr 92.5% AFUE, 30 kBtu/hr 92.5% AFUE, 50 kBtu/hr 

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 Conditioned 

Space, SA leakage = 

1%, OA leakage = 

0.23% of fan flow 

Water 

Heater Gas standard, 0.55 EF Gas standard, 0.55 EF Gas Tankless, 0.84 EF Gas Tankless, 0.84 EF 

93 
First-Cost Impacts 

For all of the 30%-39% energy-savings level example cases shown here 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 homes’ energy costs, or they may develop their own 

programs. Some cover room comfort by guaranteeing that the temperature will not vary by more 

than 3oF at the center of any room served by the thermostat. A Building America team helped to 

develop these programs. Information on three of these programs can be found at 

• Environments for Living www.eflhome.com/index.jsp 

• Engineered for Life www.us-gf.com/engineered.asp 

• The Energy Use and Comfort Guarantee www.artistichomessw.com/guarantee.htm 

(Baechler et al 2004). 

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 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. 

• 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 

• 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. 

• 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 (Baechler et al 2004). 

Table 8 shows the first costs associated with the 30% and 39% two-story example cases in 

Atlanta. These incremental costs are relative to a code minimum house consistent with the worst 

options included in the simulation, not relative to the Benchmark. 

At an 8% mortgage interest rate, an additional $1,670 first cost associated with energy efficiency 

measures only represents an additional $12 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 

94 
consumer costs in the Atlanta area or other Mixed-Humid climate areas. The actual first cost for 

energy efficiency options for a particular builder and potential homeowner in the Mixed-Humid 

climate region 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 and Cost Tradeoffs. 

Table 8. Incremental First-Cost for Two-Story Atlanta Case 

Category Atlanta, Two-story 

Incremental First-Cost 

30% Example 

Incremental First-Cost 

39% Example 

Walls $191.00 $191.00 

Ceiling $0.00 $0.00 

Infiltration $0.00 $0.00 

Crawlspace $0.00 $0.00 

Window Type $0.00 $0.00 

Dishwasher $0.00 $89.00 

Lighting $0.00 $120.00 

Air Conditioner $0.00 $0.00 

Furnace $436.00 $436.00 

Ducts $0.00 $240.00 

Water Heater $0.00 $594.00 

Total $627.00 $1,670.00 

95 
Key Cost Tradeoffs 

The analyses for single- and two-story homes in Atlanta show the main trends that result in 

homes that saves 30%-39% whole-house energy relative to the Benchmark. For houses with 30% 

energy savings, these trends are improved exterior-wall constructions, crawlspace wall 

insulation, high-performance glazing, air-sealing measures to reduce infiltration, and ducts in 

conditioned space. For houses at the upper end of the energy savings range (~39%), features 

such as tankless gas water heaters, condensing furnaces, ENERGY STAR appliances, and 

elevated levels of compact fluorescent lighting are commonly added. The results indicate that the 

main driver for energy and cost savings in Atlanta 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. Envelope measures, such as improved exterior wall constructions, 

basement wall insulation, ceiling insulation, high-performance 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 the Mixed-Humid 

climate, as shown in the case studies and supported by the results from the BEopt analysis 

method. The case studies for Tindall, Melrose Commons, Longleaf, and Frankford Estates 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 Mixed-Humid climates can 

be built on a cost-neutral basis by production builders. Table 9 shows a summary of energyrelated features for the Mixed-Humid case studies included in the following section of this report 

and examples of results from the use of the BEopt analysis method for a theoretical project in 

Atlanta. While the specific combinations of technologies used in the case studies or shown in 

BEopt results may not be cost-optimal solutions for all areas and housing types covered by the 

Mixed-Humid 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. 

96 
Table 9. Summary of Energy Features for Case Studies and BEopt Results for Atl

Case Studies 

Category 

Longleaf, Pine 

Mountain, 

Georgia 

Habitat, 

Montgomery 

County, Maryland 

Melrose 

Commons, 

Bronx, New 

York 

Frankford 

Estates, 

Baltimore, 

Maryland 

Grove Park, 

Cartersville, 

Georgia 

Ideal Homes, 

Oklahoma 

City, 

Oklahoma 

Legends at 

Mansfield, 

Columbus, 

New Jersey 

30% Point 

(One-Story) 

30% 

(Two

Whole-House 

Energy 

Savings 

30% 34% 30% 36% 32% 36% 43% 30% 3

Floor Area (ft2) 1,929 Not Described 3,300 1,960 2,000-3,000 1,400-2,300 5,000 1,500 3,

Number of 

Floors 1 3 3 3 2 1 2 1 

Number of 

Bedrooms 3 Not Described 5 3 3 3 4 3 

Number of 

Bathrooms 2 Not Described Not Described 2.5 Not Described Not Described 4 2 

Walls 

Ceiling 

2x4, 

R-13 spray foam 

R-27 

cathedralized 

attic, spray foam 

under roof deck 

2x4, R-9.5 blownin cellulose, 

R-7 spray foam, 

R-5 insulating 

sheathing 

R-38 blown 

cellulose 

R-11 in steel 

stud cavities, 

R-3 XPS on 

front and end 

walls 

R-20 polyisocyanurate 

2x6 24 in. oc, 

R-21 blown 

fiberglass 

R-40 blown 

fiberglass 

2x6 24 in. oc, 

R-20 blown 

cellulose, 

R-3 spray foam 

R-38 blown 

cellulose 

2x4, R-13 

blown-in 

cellulose, 

R-3 insulating 

sheathing 

R-30 blown 

cellulose 

2x6, R-18 

R-30 FG + 

R-19 blown 

cellulose 

R-19, 2x6, 

24 in. oc 

R-30 FG 

R-19

24 

R-3

Thermal Mass Not Described Not Described Not Described Not Described Not Described Not Described Not Described 1⁄2-in. Ceiling Drywall 1⁄2-in. 

Dr

Infiltration 

Basement/Slab/ 

Crawl space 

Glass Type 

Not Described 

Raised slab-ongrade 

Double-pane, 

argon-filled, 

low-E, 

spectrally 

selective, 

U = 0.38, 

SHGC = 0.35 

2.5-in2 leakage 

area per 100 ft2 

thermal envelope 

area 

Insulated 

slab-on-grade, 

R-7.5 under slab 

Double-pane, 

low-e, 

spectrally 

selective, 

U = 0.33, 

SHGC = 0.33 

0.07-0.10 

ACHann 

Uninsulated 

basement 

Low-e, 

vinyl frame 

Not Described 

Basement, 

R-14 rigid 

insulation, 

half height 

Double-pane, 

low-e, 

spectrally 

selective, 

U = 0.35, 

SHGC = 0.29 

0.31-0.47 

ACHann 

Uninsulated 

slab-on-grade, 

R-26 framed 

floors 

Double-pane, 

low-e, 

spectrally 

selective, 

U = 0.36, 

SHGC = 0.33 

2.5-in2 

leakage area 

per 100 ft2 

thermal 

envelope area 

0.22 ACHnat 

Slab-on-grade, 

R-4 perimeter 

insulation 

Basement, 

R-12.5 

exterior rigid 

Double-pane, 

low-e, 

spectrally 

selective, 

U = 0.39, 

SHGC = 0.31 

Double-pane, 

low-e, U=0.36, 

SHGC=0.33 

SLA = 0.0003 

Unvented, R-11 

interior 

insulation 

Two-pane, Lowe, spectrally 

selective, 

U = 0.30, SHGC 

= 0.34, vinyl 

frame 

SLA = 

Unven

11 in

insu

Two

Low-

tint, U 

SHGC 

vinyl 

97 
Table 9 (continued). Summary of Energy Features for Case Studies and BEopt Results 

Case Studies BEopt r

Category 

Longleaf, 

Pine 

Mountain, 

Georgia 

Habitat, 

Montgomery 

County, 

Maryland 

Melrose 

Commons, 

Bronx, New 

York 

Frankford 

Estates, 

Baltimore, 

Maryland 

Grove Park, 

Cartersville, 

Georgia 

Ideal Homes, 

Oklahoma 

City, 

Oklahoma 

Legends at 

Mansfield, 

Columbus, 

New Jersey 

30% Point 

(One-Story) 

30% Point 

(Two-Story) 

Window Area 

per Wall 

Not 

Described 

Not 

Described 

Not 

Described 

Not 

Described 

Not 

Described 

Not 

Described 

Not 

Described 

270 ft2, 12.5% 

N&S, 50% W, 

25% E 

540 ft2, 12.5% 

N&S, 50% W, 

25% E 

Refrigerator ENERGY STAR ENERGY STAR ENERGY STAR ENERGY STAR ENERGY STAR ENERGY STAR Not Described Standard - 671 kWh/yr Standard - 671 kWh/yr Cooking Range 

Not 

Described 

Not 

Described 

Not 

Described 

Not 

Described 

Not 

Described 

Not 

Described 

Not 

Described 45 Therms/yr 45 Therms/yr 

Standard, 462 

kWh, eight place 

Dishwasher ENERGY STAR ENERGY STAR ENERGY STAR ENERGY STAR ENERGY STAR ENERGY STAR Not Described 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 

Gas - 5.7 ft3 , Gas - 5.7 ft3 , 

Clothes Dryer Not Described Not Described Not Described Not Described Not Described Not Described Not Described 2.75 EF, 70.1 kWh/yr, 

31.8 therms/yr 

2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Clothes Washer 

Not 

Described 

ENERGY 

STAR 

Not 

Described 

Not 

Described 

Not 

described 

ENERGY 

STAR ENERGY STAR 

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 10% fluorescent 90% CFL 100% fluorescent 100% fluorescent 0% fluorescent 10% fluorescent 95% fluorescent 20% CFL, 877 kWh/yr hardwired, 331 plug in 0% CFL, 2634 kWh/yr hard- wired, 571 plug in 

14 SEER 13 SEER Two 13 Two 12 14 SEER One 14 SEER 3 SEER 13, 1.5 SEER 13, 2.5 

Cooling air-source air-source No cooling SEER air SEER air air ton, one 13 tons, 0.364 tons, 0.364 

heat pump heat pump conditioners conditioners conditioner SEER 2.5 ton W/CFM AH Fan W/CFM AH Fan 

98 
Table 9 (continued). Summary of Energy Features for Case Studies and BEopt Results 

Case Studies BEop

Category 

Longleaf, 

Pine 

Mountain, 

Georgia 

Habitat, 

Montgomery 

County, 

Maryland 

Melrose 

Commons, 

Bronx, 

New York 

Frankford 

Estates, 

Baltimore, 

Maryland 

Grove Park, 

Cartersville, 

Georgia 

Ideal Homes, 

Oklahoma 

City, 

Oklahoma 

Legends at 

Mansfield, 

Columbus, 

New Jersey 

30% Point 

(One-Story) 

30% Point 

(Two-Story) 

Heating 

8.0 HSPF 

air-source 

heat pump 

8.5 HSPF 

air-source 

heat pump 

86% AFUE 

direct-vent 

boiler, 

hydronic 

baseboard 

Two 93% 

AFUE, 

direct-vent 

gas furnaces 

Two 92% 

AFUE, 

gas furnaces 

90% AFUE, gas furnace 

Two 92.1% 

AFUE, gas 

furnaces 

80% AFUE, 30 

kBtu/hr 

92.5% AFUE

50 kBtu/hr 

Ducts 

100% inside 

conditioned 

space 

Inside 

conditioned 

space, 

R-4 insulation 

No ducts 

Inside 

conditioned 

space 

Buried in attic 

insulation, 

R-3 spray foam, 

90-150 cfm 

leakage to 

outside @ 25 

Pa 

In vented 

attic, 

R-6 

insulation, 

<5% leakage 

to outside 

Inside 

conditioned 

space 

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 

Ventilation 

Passive inlet 

to return side 

of AH 

Not Described Continuous 

exhaust 

Continuous 

exhaust 

No mechanical 

ventilation 

Central fan 

integrated 

supply, 46 

cfm average 

HRV Continuous 

exhaust 

Continuous 

exhaust 

Water 

Heater 

40-Gal. 

Electric, 

0.93 EF 

0.9 EF 

electric tank 

65-gal, indirect tank heated by 

boiler 

Gas tankless, 

0.82 EF 

40 gallon, 

0.59 EF gas 

tank 

0.59 EF gas 

tank 

Gas tankless, 

0.85 EF 

Gas standard, 

0.55 EF 

Gas standard

0.55 EF 

On-site 

Power 

system 

None None 2.2-kW PV on prototype None None None None None None 

99 
Table 10 summarizes the source of the energy savings by end use for each of the seven case 

studies. Figure 23 shows the geographic location for each of the case studies. Locations are 

indicated with stars. 

Table 10. Summary of Source Energy Savings by End-Use 

for the Mixed-Humid Climate Case Studies 

Percent Source Energy Savings 

End Use 

Longleaf, 

Pine 

Mountain, 

Georgia 

Habitat, 

Montgomery 

County, 

Maryland 

Melrose 

Commons, 

Bronx, 

New York 

Frankford 

Estates, 

Baltimore, 

Maryland 

Outlook 

Grove Park, 

Cartersville, 

Georgia 

Ideal Homes, 

Oklahoma 

City, 

Oklahoma 

Legends at 

Mansfield, 

Columbus, 

New Jersey 

Space Heating 39% 75% 50% 51% 52% 38% 53% 

Space Cooling 57% 56% 2% 49% 72% 59% 45% 

DHW 28% 1% 30% 35% 13% 10% 55% 

Lighting -4% 67% 66% 52% -8% 70% 68% 

Appliances + 

MEL 5% 4% 9% 2% 3% 9% 5% 

Total Energy 

Use 

30% 34% 30% 36% 32% 36% 43% 

Number of 

Homes 

30 24 210 78 73 208 39 

100 
101 

Figure 23. Locations of 30% Mixed-Climate case studies 

⌂⌂

⌂

⌂
Community Case Studies 

Development: Longleaf at Callaway 

Builder: Pine Mountain 

Location: Pine Mountain, Georgia 

Longleaf at Callaway (Figure 24) is the first community to meet the standards of quality 

necessary to be associated with Georgia’s famed Callaway Gardens, a wetland-based nature 

preserve owned by the Ida Cason Callaway Foundation – a non-profit organization dedicated to 

land stewardship and environmental education. 

When the community was first conceived, Cousins 

Properties, a highly-diversified Atlanta-based real estate 

developer, began walking the land with Callaway’s own 

horticulturists and leading environmental experts. Their 

goal was to create a quiet, environmentally friendly 

community that would value and protect the land. 

Cousins specifically set its sights on 30% energy savings 

levels and needed a builder to help carry that vision 

forward – enter Fortress Construction. 

Fortress Construction, which builds 

approximately 40 homes each year 

in the Atlanta area, is focused on 

building to higher performance 

standards. A certified professional 

home builder, Fortress 

Construction is an ENERGY 

STAR Homes® partner and one of 

the first EarthCraftTM House 

builders. Before entering this joint 

venture with Cousins and 

becoming Pine Mountain, they 

were already meeting levels near 

30% whole-house energy savings. 

David Barnes of Pine Mountain 

said “We (Fortress Construction at the time) didn’t really have to change our building process. 

We just had to identify where we could get the most ‘bang for our buck’ in order to meet or 

exceed 30% energy savings. Given our climate, we thought that an improved energy envelope 

and HVAC system would have immediate impact.” 

Icynene® low-density spray-foam insulation was a key component to sealing the energy 

envelope. Pine Mountain employed Icynene within all walls and along the roof deck in the attic 

creating a cathedralized attic space. Insulating the attic in this way created a 100% conditioned 

space for the HVAC system and ductwork. 

Figure 24. Neighborhood map and home from 

Longleaf at Callaway 

102 
Better insulation, air sealing, and creating the conditioned space in the attic were vital to 

reducing the energy load and improving performance of the HVAC systems in Longleaf homes. 

In addition, Pine Mountain installed programmable thermostats, heat pump units with HPSF 8.0, 

and 14 SEER air conditioning in each of their homes. Table 11 lists all of the efficient 

specifications utilized at Longleaf at Callaway. 

At the same time, the Pine Mountain partners decided to keep the ideals of the Callaway 

Foundation in mind, disturbing the land as little as possible. Longleaf at Callaway is built on land 

that is subject to periodic heavy rains and is adjacent to acres of preserved wetlands. In order to 

let the water follow its natural course with minimal grading, Pine Mountain elected to build the 

homes on raised slab-on-grade foundations with 4-ft-high stemwalls. While not specifically 

required as an energy feature, this practice proved to be not only environmentally friendly, but 

also prudent for the durability of the homes – by minimizing the chance of water damage. 

Source Energy Consumption Summary 

An analysis of energy use for the Longleaf at Callaway specifications, in comparison to the 

Building America Benchmark, shows that the Pine Mountain homes were estimated to consume 

30% less energy. Table 12 lists source energy use and savings for the Longleaf at Callaway 

community. Savings are relative to the Benchmark. Note that the “Percent of End-Use” column 

shows how effective the prototype building is at reducing energy use in space heating and 

cooling, as well as domestic hot water end-use. The “Percent of Total” column shows how the 

energy reductions in each end-use category contribute to the overall savings. 

Table 11. Longleaf at Callaway House Specifications 

Building Envelope 

Ceiling R-27 cathedralized attic (Icynene under roof deck) 

Walls 2x4 wood framing @ 16 in. oc (0.23 framing factor) 

R-13 Icynene insulation 

Floor Raised slab-on-grade, uninsulated 

Windows Low-e, gas-filled; U = 0.38; SHGC = 0.35 

Infiltration Tight construction, utilizing the airtightness benefits 

of Icynene insulation. Tested at 2.79 ACH50 

Mechanical 

Systems 

Heating HPSF 8.0 heat pump with programmable 

thermostat 

Cooling 14 SEER heat pump 

Ducts All ductwork located in conditioned space 

Tested tight ducts - 0 % leakage to the outside 

Water Heating 40 Gal. Electric, 0.93 EF 

Lighting 10% fluorescent 

103 
Table 12. Summary of Estimated End-Use Source Energy 

Estimated Annual Source Energy Source Energy Savin

Benchmark Prototype Percent of End-Use Perce

End Use (MBtu/yr) (MBtu/yr) vs. Benchmark vs. B

Space Heating 63 38 39% 

Space Cooling 80 34 57% 

DHW 34 24 28% 

Lighting 21 22 -4% 

Appliances+ Plug 65 64 2% 

OA Ventilation 0 0 0% 

Total Usage 262 182 31% 

104 
Builder Cost Summary 

Table 13 summarizes the incremental costs to the builder. While Pine Mountain has invested 

approximately $6,835 in first costs over comparable homes in the greater Atlanta market, the 

builder believes that the added cost is definitely worthwhile, in terms of energy efficiency, 

environmental impact, and customer satisfaction. Table 14 summarizes the cash-flow analysis 

for the buyer. Amortized costs are based on a 30-year mortgage at 7% interest. While the 

additional cost of the 30% building practices cost the buyer $547 annually, they are saving $663 

annually in energy costs. This translates to a net positive cash flow for the homeowner of $116 

per year. Because of Pine Mountain’s commitment to high-performance building practices, 

Longleaf homes are now viewed by homebuyers and realtors as the best value in the region. 

According to Barnes, the conditioned space in the cathedralized attic turned out to be a great 

selling feature during home tours. “Buyers could not believe how well-insulated and comfortable 

the attic space is. Our salespeople were able to position the ‘top floor’ as additional living space, 

rather than exclusively for storage, which was a big plus for the customer.” 

Investments in 30% building practices are also translating into bottom line benefits for residents 

who have made Longleaf their home. In fact, one resident contacted Pine Mountain to thank 

them for a $125 power bill they received in February. 

Pine Mountain has 109 homes under contract or completed with 15 homes currently under 

construction all at the 30% energy-savings level. By the end of 2006, all 137 properties in the 

Callaway community are slated to be sold, and construction will be completed by the fall of 

2007. 

105 
Table 13. Longleaf at Callaway Pricing 

Standard Construction Longleaf at Callaway 

Estimated 

Cost 

Difference 

Building envelope 

Ceiling R-30 batt in vented 

attic 

Walls R-15 2x4 wood framing 

@ 16 in. o/c 

Clear glass, Windows 

U = 0.65; SHGC = 0.40 

Mechanical 

systems 

HVAC HPSF 7.7 / 13 SEER 

heat pump 

Ventilation None as standard 

R-27 cathedralized attic 

(Icynene under roof deck)

2x4 wood framing @ 16 

in. oc (0.23 framing factor) 

R-13 Icynene insulation 

Low-e, gas-filled, 

U = 0.38; SHGC = 0.35 

 $5,325 

See Icynene 

cost above 

$660 

HPSF 8.0/14 SEER heat 

pump 

Passive inlet to return 

side of air handler

 $600 

$250 

Total = $6,835 

Table 14. Longleaf at Callaway Cash Flows 

Package 30% Savings 

Total Cost $6,835 

Annual Amortized $547 

Cost 

Annual Energy $663 

Savings 

Net Savings $116 

106 
Development: Linganore Woods 

Builder: Habitat for Humanity 

Location: Montgomery County, Maryland 

Figure 25. Front elevation of Habitat multi-family project 

Habitat for Humanity in Montgomery County, Maryland, is building a multi-family project 

(Figure 25) using a design that had its origin long before becoming involved with Building 

Science Corporation (BSC) and Building America. Prior to this project in Montgomery County, 

building officials had put their foot down on mid-construction changes after noticing projects 

were growing subsequent to the permitting process – builders were trying to maximize the value 

of their efforts, without being subjected to issues that might have arisen during permitting. The 

relevance is that it would have extended the timeframe for getting a permit had significant 

changes been necessary, and they had already been waiting 9 months with their current 

submission. Where BSC typically has input during the design process, in this case they needed to 

adapt techniques for including slab insulation and air-sealing details using methods that could fly 

under the radar and not impact the structural characteristics of the building. A wall section of the 

final design is shown in Figure 26, and the key specifications are listed in Table 15. 

The use of insulating sheathing, which often throws builders for a loop, was not cited as a 

problem for Habitat, no doubt because of the experience of the construction manager. The floor 

presented another challenge and one where BSC was not able to use their preferred approach of 

foundation insulation, interior to a stem wall and under the floor. Habitat’s design used a grade 

beam / slab-on-grade approach. In light of the permitting difficulties, BSC’s recommendation 

was to insulate on top of the slab, with subfloor covering the foam layer. 

Air sealing was another area of design guidance. Reducing air leakage is critical for minimizing 

the energy use of buildings, and one of the best methods for reducing air leakage is the use of 

spray-foam insulation. Using spray foam in a few key locations will significantly improve the air 

leakage, without killing the budget for the project. Key air-leakage areas include rim joists and 

wall-to-ceiling or -roof connections. 

107 
Figure 26. Montgomery County Habitat wall section 

108 
Table 15. House Specifications 

Feature Building America Version 

Building envelope 

Ceiling R-38 flat attic blown insulation 

Walls R-5 sheathing, R-7 spray foam, R-9.5 cavity insulation: R-21.5 

Foundation Slab, R-7.5 1.5 in. XPS on slab, below plywood sub-floor 

Windows Low-E windows, U = 0.33, SHGC = 0.33 

Infiltration 2.5-in2

 leakage area 

per 100 ft

2

 envelope 

Mechanical systems 

Heat 8.5 HSPF ASHP 

air handler in conditioned space (utility room) 

Cooling 13 SEER split system in conditioned space 

DHW 0.9 EF Electric hot water tank 

Ducts R-4.2 flex runouts in dropped ceiling or in floor joists 

Leakage none to outside (5% or less) 

Ventilation Central fan integrated outdoor-air supply to return of air handler 

33% Duty Cycle: 10 minutes on; 20 minutes off 

60-80 CFM continuous average flow 

Return Pathways Transfer grilles/jump ducts at bedrooms 

109 
Benchmark 

Bldg Config Changes 

Window Upgrade 

Insulating Sheathing 

R-38 Roof 

Air Seal 

Ducts Inside 

13 SEER 

8.5 HSPF 

0.94EF Hot Water 

90% CFL Package 

Energy Star Appl. 

Parametric Study 

Figure 27 charts overall source energy-use reduction and shows that the heating, cooling, and 

lighting loads are greatly diminished with the recommended improvements. Table 16 shows the 

results in tabular form. Table 17 shows source energy savings by end-use. 

Parametric Annual Loads Study 

0 

500 

1000 

1500 

2000 

2500 

10^6 Btu/year 

Heating Cooling Hot Water Lighting Other 

Figure 27. Montgomery County Habitat parametric analysis 

Table 16. Summary of Parametric Study 

Building 1 Parametric Simulation Total Source Energy Savings

 (H/C/DHW/Lights/Appliances/Plug) 

Estimated Estimated 

Parametric Individual Cumulative over BA Incremental Annual Item Simple Increment 

Run ID Description of change Cost of change Cost of change Benchmark1 Over Bmrk energy cost Savings payback (yr) payback (yr) 

0 Benchmark n/a n/a n/a n/a $15,192 n/a n/a n/a 

1 0 + Envelope, window configuration changes n/a n/a 7.0% n/a $14,126 n/a n/a n/a 

2 1 + Windows: U-0.33, SHGC-0.33 $2,400 $2,400 9.1% 2.1% $13,802 $1,390 2 7 

3 2 + R-15 batt+ R-5 Insulating Sheathing $600 $3,000 11.7% 2.6% $13,410 $392 2 2 

4 3 + Upgrade ceiling insulation to R-38 $600 $3,600 12.3% 0.5% $13,328 $82 2 7 

5 4 + Air seal building to 2.5 sqin/100sf $1,200 $4,800 21.7% 9.4% $11,896 $1,432 1 1 

6 5 + Ducts inside, tightened to 5% leakage $600 $5,400 25.0% 3.3% $11,398 $498 1 1 

7 6 + Upgrade SEER to 13 $600 $6,000 26.5% 1.5% $11,163 $235 1 3 

8 7 + Upgrade HSPF to 8.5 $100 $6,100 27.7% 1.2% $10,988 $175 1 1 

9 8 + High Efficiency hot water 0.94EF $2,400 $8,500 27.8% 0.2% $10,962 $26 2 92 

10 9 + 90% CFL Lighting $600 $9,100 32.8% 5.0% $10,209 $753 2 1 

11 10 + Energy Star Appliances $1,200 $10,300 33.9% 1.1% $10,037 $172 2 7 

110 
-

-

Source Energy Consumption Summary 

Note that the “Percent of End-Use” column shows how effective the prototype building is at 

reducing energy use in each end-use category. The “Percent of Total” column shows how the 

energy reductions in each end-use category contribute to the overall savings. 

Table 17. Source Energy Savings by End-Use 

Percent of End Use Percent of Total 

BA Benchmark Prototype 1 Prototype 1 savings Prototype 1 savings 

End Use 106 BTU/yr 106 BTU/yr 

Space Heating 502 125 75% 19% 

Space Cooling 276 122 56% 8% 

DHW 391 388 1% 0% 

Lighting 155 52 67% 5% 

Appliances + Plug 622 598 4% 1% 

Total Usage 1946 1285 34% 34% 

Site Generation 0 0 0% 

Net Energy Use 1946 1285 34% 34% 

Source Energy Savings 

Estimated Annual Source Energy 

Summary 

With improvements that were able to be retrofitted into an existing design for modest change and 

costs, the energy consumption of the building was greatly reduced. Also, the improvements will 

create more comfortable interior conditions for the occupants throughout the houses, giving a 

non-calculable benefit of more useful space per square foot of house area. 

111 
Figure 28. Melrose Commons 

Development: Melrose Commons 

Builder: Blue Sea Construction 

Location: Bronx, New York 

Background 

Melrose Commons (Figure 28), a community of 70 

three-family townhomes located in the South Bronx, 

New York, exemplifies how high performance and 

affordability can successfully be combined to create 

a home that is not just affordable to purchase, but 

affordable to maintain as well. Typically, affordable 

housing in New York City is built to be affordable 

on a first-cost basis, making maintenance and energy 

costs a burden to homebuyers and not-for-profit 

organizations that own or manage such buildings. 

Melrose Commons breaks this mold, implementing 

advanced technologies and Building America design 

strategies that lower the life-cycle costs. 

The first phase of the project, Melrose Commons II, 

was funded by the New York City Department of 

Housing Preservation and Development through the 

New York City Partnership. Developed by MC II 

Associates and built by Blue Sea Construction in 

2002, these 30 initial townhomes were the first 

affordable three-family housing in New York State 

that met the U.S. Environmental Protection Agency 

(EPA) and the New York State Energy Research and Development Authority (NYSERDA) 

ENERGY STAR standards. The homes were designed for first-time homebuyers, promoting 

small business in the community. The basement, the first full floor, and half of the second floor, 

comprise the owner’s two-bedroom residence. There is a half-floor one-bedroom apartment on 

the second floor and a full-floor two-bedroom apartment on the top floor. The top two units can 

be rented out to further subsidize the already affordable mortgage. 

Based on the success of Melrose Commons II, the builder, Blue Sea Construction, continued the 

efficient, affordable construction practices in the neighboring Melrose Commons III. This phase 

consisted of 40 three-family townhomes, built to the same specifications as Melrose Commons 

II, and was completed in October 2003. One distinct difference was the addition of a 2.2-kW 

solar electric system (Figure 29) on the roof of one of the townhomes. Blue Sea took advantage 

of funding available through the NYSERDA ENERGY STAR/PV Demonstration project to 

assess the true costs for installing such a system, including costs incurred by the roofers, 

electricians, and the PV contractor. 

112 
The completion of these projects brought much-needed 

affordable housing to a community in the midst of 

revitalization. The architecture is such that the homes blend 

well with the surrounding buildings. The homes feature 

three-story-high precast concrete panels that form an 

elegant stone and brick façade. Crown lintels project over 

windows and doors and a detail cornice caps the perimeter 

(Figure 30). Totaling 296,100 ft2 of dwelling space, the 

homes span four city blocks in the Melrose section of the 

Bronx. The builders and the owners benefited from 

advanced housing technologies that accent affordability, 

durability, and marketability. 

In January 2004, Melrose Commons II was awarded the 

U.S. Department of Housing and Urban Development 

(HUD) Secretary’s Platinum Award for Excellence in the 

20th Annual Best in American Living Award Competition. In 2005, Melrose Commons earned 

the NAHB’s Energy Value Housing Silver Award. The development also won first-place in the 

residential category of the Northeast Sustainable Energy Association’s (NESEA) 2003 Green 

Building Awards, competing against high-end, single-family custom homes. 

Advanced Technologies 

Design considerations for Melrose Commons primarily focused on energy efficiency, 

sustainability, and affordability. Below is a summary of several of the advanced technologies 

incorporated into the 210-home development. 

Figure 29. Solar system 

Figure 30. Crown lintels over windows 

113 
Figure 31. Precast concrete 

panelized wall system 

Oldcastle Precast Concrete Wall Panels 

The Oldcastle precast concrete panelized wall system 

(Figure 31) offered the builder a means to fast and 

efficient home construction in lieu of the typical blockand-plank method. The development featured three 

separate types of unit: end units with three exposed 

exterior walls; middle units with two exposed exterior 

walls; and detached units with four exposed exterior 

walls. Each of the 22-ft-wide and 50-ft-deep homes were 

constructed from five major precast concrete elements: 

(1) load-bearing panels to support precast floor planks 

and roof; (2) non-load bearing panels with decorative 

precast windows and exterior brick facade; (3) U-shaped 

panels for entry facade; (4) cornice capping the exterior 

perimeter; (5) and exterior stairs. The project also used 

hollow-core panels for the floor and roof. The hollow 

core panels offered the same durability and strength of 

traditional precast panels but weighed significantly less. 

The exterior face of the exterior panels featured a thin 

brick inlay, a new feature of the Oldcastle panels. 

The placement of bricks in the panel is feasible as a 

result of the self-compacting mixture created by the 

addition of superplasticizers. The self-compacting mixture eliminates the need to vibrate the 

forms to achieve a uniform consistency. 

The panels took approximately 3 months to manufacturer. After the site was prepared and the 

foundation was laid, the panels were shipped to the Melrose Commons site where they were 

quickly erected with a crane. The first 30 buildings were constructed with a six-man erection 

crew – one welder, one grouter, and four assemblers – in the span of 4 months. After the panels 

were placed, the building crew air sealed around floor, electrical boxes, and inside to outside 

connections. 

The use of panels was beneficial in respect to both construction and energy efficiency. Typical 

practices in this urban neighborhood called for concrete block-and-plank construction. The 

panels arrived on the site ready to be placed together, allowing for speedy construction 

throughout the cold and wet winter months. This, in turn, made financing the project easier by 

reducing carrying charges and the opportunity for theft and vandalism. Because the panels were 

fabricated off site to exact specifications, the amount of on-site waste was significantly reduced. 

Concrete as a material offers increased durability and fire resistance. The use of precast concrete 

panels increased the tightness of the building envelope. Each panel spanned the entire side of a 

unit, reducing the number of seams and, therefore, opportunities for infiltration. 

High-Performance Insulation Strategy 

Rigid Insulation. CARB conducted THERM analysis of the initial insulation specification and 

found that a significant amount of thermal bridging would occur between the concrete exterior 

and the metal studs. To reduce this potential failure in R-value, CARB suggested using a 1/2-in. 

114 
extruded polystyrene (XPS) board (Figure 32) between the exterior walls and interior metal 

studs. The rigid insulation was installed throughout the complex and provided a significant 

barrier to thermal bridging. R-11 fiberglass batts were then installed in the steel framed cavity. 

Figure 33. Sealed-combustion, directvent, gas-burning Burnham Revolution 

boiler with a 65-gal. Bradford-White 

automatic-storage water heater 

Figure 32. Extruded polystyrene board between the 

exterior walls and interior metal studs 

Energy Efficient, Integrated Space heating 

and Domestic Hot Water Sealed 

Combustion Boiler. Each three-family home 

comes equipped with a single sealedcombustion, direct-vent, gas-burning 

Burnham Revolution boiler with a 65-gallon 

Bradford-White automatic-storage water 

heater (Figure 33). The single boiler system 

in each home provides both heating and hot 

water to all thee units. The boilers are 

ENERGY STAR-certified and have an 

AFUE rating of 87. Properly accounting for 

the building’s insulation, reduced air 

infiltration, and heating load allowed the 

boiler in the Melrose Commons units to be 

properly sized with an output rating of 164 

kBtu/h. 

115 
Mechanical Ventilation. Because of the tightness of the precast concrete building envelope, 

controlled mechanical ventilation was needed to ensure that the homes have adequate fresh air to 

dilute pollutants and remove humidity from the home. 

CARB recommended an “exhaust-only” strategy as the most effective and affordable solution for 

this situation where heating is the predominant load and there is no central air conditioning or 

ducted air-distribution system. This approach requires one bath fan in each of the homes be 

upgraded to a model that has been rated for energy-efficient operation, continuous use, and quiet 

running. An efficient fan will not be costly for the homeowner to operate. A fan rated for longer 

run times will not fail after a few months of operation. And lastly, the homeowner is less likely 

to disable the fan if it runs quietly. 

This ventilation system complies 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 Low-rise Residential Buildings. 

Renewable Energy 

Photovoltaic System 

As part of a NYSERDA demonstration project, Blue Sea Construction installed a 2.2-kW 

photovoltaic system on one townhome to assess costs and feasibility. Most of the funding for the 

solar equipment and installation was provided by NYSERDA. Monitoring shows that generation 

varies between 3 kWh/day in the winter to 0 kWh/day in the summer. Annual production is 

approximately 2,400 kWh ($432) in electricity savings each year. 

Additional Features 

To complement the energy-efficient elements utilized in these townhomes, “green” components 

were also considered to reduce the overall environmental footprint of these units. Additional 

features that were incorporated into this project are listed below: 

• Low-VOC paints, caulks, sealants, and adhesives 

• Recycled-content kitchen VCT flooring 

• Solid wood and plywood used in lieu of particle board in cabinets and countertop substrates 

with low-VOC lacquer finishes 

• 100% recycled content PET carpeting and recycled rubber padding 

• ENERGY STAR compact fluorescent lighting fixtures throughout the home 

• ENERGY STAR refrigerators and dishwashers 

• Low-flow fixtures and dual-flush toilets 

• Digital programmable thermostats and computer boiler control with outdoor temperature 

sensors 

• Large double-glazed low-e vinyl windows to increase natural lighting 

• Concrete with high fly ash content was used in precast panels. 

116 
Overall Building Specification 

These affordable homes feature much higher quality construction than is typical in similar New 

York City housing. Table 18 displays the improvements made at Melrose Commons over 

standard block-and-plank construction. 

Table 18. Summary of Key Specifications 

 Melrose Commons Standard Block and Plank 

Front and 

End Wall 

Construction 

Steel studs inside pre-cast concrete 

panels 

Steel studs inside laid 

concrete blocks 

Insulation 

R-11 in stud cavities, R-3 XPS 

break R-11 in stud cavities 

Rear Wall Construction 

Steel studs, exterior gypsum, 

aluminum siding 

Steel studs, exterior gypsum, 

aluminum siding 

Insulation R-11 in stud cavities R-11 in stud cavities 

Windows Insulated, low-e glazing, vinyl 

frames 

Insulated, clear glazing, metal 

frames 

Roof Insulation R-20 Polyisocyanurate R-20 Polyisocyanurate 

Basement Insulation Not effective Not effective 

Space 

Heating 

Equipment Direct vent boiler, 86% AFUE Atmospheric boiler, 80% 

AFUE 

Distribution Hydronic Baseboard Hydronic Baseboard 

Control 4 zones, reset control Single zone 

Domestic Hot Water Indirect tank heated by boiler Atmospheric tank, 0.54 EF 

Lighting All permanent fixtures fluorescent Fluorescent in kitchen only 

Appliances All supplied appliances Energy Star Standard appliances 

Ventilation 

Each unit has one low-sone, 

efficient bath fan running 

continuously (50-60 CFM). 

Standard fixtures; no 

automatic ventilation. 

Energy and Cost Information 

Home Energy Performance 

The Melrose Commons townhomes received ENERGY STAR certification. Blower-door tests 

revealed consistently well-sealed envelopes with leakage ranging from 0.07 to 0.10 ACHnat. 

Classic HERS scores ranged from 88.9 to 89.5. To determine the percentage improvement over 

the Building America Benchmark, REM/Rate software was used to determine the annual energy 

consumption from space heating, cooling, and water heating. Tables 19 and 20 show the 

estimated annual performance of the regional standard, the builder’s standard, and the prototype 

versus the Benchmark. The values in the Benchmark column refer to the reference home for a 

single Melrose Commons unit. The average Melrose Commons unit is estimated to consume 

30% less source energy than a similar home built to the Benchmark specifications. 

117 
-

-

Table 19. Benchmark Analysis, Summary of Site Energy Consumption 

by End Use 

Annual Site Energy 

kWh Therms 

BA Benchmark 

kWh Therms 

Region Standard 

kWh Therms 

Builder Standard 

kWh Therms 

BA Prototype 

End Use 

Space Heating 0 939 0 761 0 761 0 472 

Space Cooling 2533 0 2450 0 2450 0 2472 0 

DHW 0 397 0 369 0 369 0 276 

Lighting 3244 1909 1909 1109 

Appliance/Plug Load 8300 186 7382 186 7382 186 7382 186 

OA Ventilation 332 368 368 368 

Total Usage 14409 1522 12109 1316 12109 1316 11331 934 

Site Generation 0 

Net Energy Use 14409 1522 12109 1316 12109 1316 11331 934 

Table 20. Benchmark Analysis, Summary of Source Energy Consumption 

Benchmark Region Builder Proto BA Reg Bldr BA Reg Bldr 

End Use MBtu/yr MBtu/yr MBtu/yr MBtu/yr Base Base Base Base Base Base 

Space Heating 96 78 78 48 50% 38% 38% 15% 11% 11% 

Space Cooling 27 26 26 27 2% -1% -1% 0% 0% 0% 

DHW 40 38 38 28 30% 25% 25% 4% 4% 4% 

Lighting 35 21 21 12 66% 42% 42% 7% 3% 3% 

Appliance/Plug Load 108 99 99 99 9% 0% 0% 3% 0% 0% 

OA Ventilation 4 4 4 4 -11% 0% 0% 0% 0% 0% 

Total 311 265 265 217 30% 18% 18% 30% 18% 18% 

Site Generation 0 0% 0% 0% 

Net Energy Usage 311 265 265 217 30% 18% 18% 30% 18% 18% 

Annual Source Energy Percent of End-Use Percent of Total

Source Energy Savings 

Cost 

Blue Sea Construction provided CARB with costs incurred to improve the homes over Blue 

Sea’s standard construction (Table 21). Costs for the single 2.2-kW photovoltaic system, 

including extra work required by roofers and electricians, totaled approximately $24,000. Most 

of the funding for the solar equipment and installation was provided by NYSERDA. Other 

incremental costs are shown below. 

For a community that is accustomed to high maintenance costs and substandard housing, these 

award-winning, affordable homes are proof that there is a better, more efficient, more sustainable 

alternative by implementing Building America design strategies (Figures 34, 35, and 36). 

118 
Table 21. Constructions Costs Incurred to Improve the 

Performance of the Melrose Homes 

Incremental Cost per 

Improved System/Specification Three-family Home 

1/2" rigid insulation outside of metal studs $675 

Double glazed, low-e, vinyl-framed windows $896 

60 gallon indirect water heater $928 

87% efficient 164kBtuh sealed combustion 

boiler $1,897 

Digital, programmable thermostats $184 

Outdoor reset control $459 

Energy Star Refrigerators $45 

Energy Star Dishwasher 18 

Compact fluorescent lighting fixtures $375 

Total Increased Costs $5,492 

NYSERDA Energy Star Homes Incentive ($1,000) 

Net Cost to Builder $4,492 

119 
Figure 34. Basement and first-floor plans 

120 
Figure 35. Second- and third-floor plans 

121 
Figure 36. Site plan for Melrose Commons III 

122 
Development: Frankford Estates 

Builder: Struever Rouse 

Location: Baltimore, Maryland 

Background 

In response to a 2002 DOE solicitation for State Energy Program Special Projects under the 

Building America Program, the Maryland Energy Administration (MEA) submitted a proposal to 

implement an “Energy Efficient and Green Technology Building Templates Program.” The 

MEA promotes energy efficiency and conservation, which in turn facilitates economic 

development, reduces reliance on foreign fuel supply, and improves the environment. The grant 

was awarded in July 2002 and the Consortium of Advanced Residential Buildings (CARB) was 

selected to provide technical assistance. CARB began working with MEA to select suitable 

builder partners and locate potential sites for this project. Once contracts and funding were in 

place, a kick-off meeting was held in Baltimore in mid-May 2003. Unfortunately, because of 

logistical problems with the initial building participants, the project was delayed and did not get 

off the ground at that time. Interest in this project was renewed, and CARB began to coordinate 

the next steps with MEA in early May 2005. 

The purpose of this grant is to implement the “Energy Efficient and Green Technology Building 

Templates” in partnership with selected Maryland Homebuilders of new construction and 

rehabilitation projects. This case study focuses on the construction of three new attached 

townhouses that exceed the total energy performance of the 1993 MEC by 50%. This equates to 

an approximate total annual source-energy savings of 30% when compared to the Building 

America Benchmark Definition (Hendron 2005). The project also incorporates green building 

components with regards to the construction materials (caulk, adhesives, insulation, etc.) and the 

finishing elements (flooring, fixtures, paint, etc.) 

The builder partner selected for the new construction portion of the project is 

Struever Rouse Homes. A division of Struever Bros., Eccles & Rouse, Inc., a 

pioneer of Baltimore's real estate landscape, Struever Rouse Homes is 

committed to an enduring legacy of building homes and neighborhoods that 

exemplify the finest urban living options available in today’s marketplace. 

The three townhomes selected for this project were 

built in one of Struever Rouse Homes’ newest 

communities, called Frankford Estates (Figures 37 and 38). Frankford 

Estates is a “Green-Friendly” community that was built with many ecofriendly options. The housing development includes townhomes, 

duplexes, and single-family homes. This unique community also 

incorporates a pool, clubhouse, playground, and 18 acres of beautifully landscaped grounds into 

a friendly living environment. The attached prototype townhomes are three stories with a walkout basement. In each townhome, the 1,960 ft2

 of living space (excluding unfinished basement) 

includes three bedrooms and 2.5 baths. The basement was finished in the middle unit. 

123 
Figure 37. Frankford Estates townhouses 

Figure 38. The three townhomes selected for this project 

124 
Advanced Technologies 

Design considerations for Struever Rouse Homes primarily focused on the building envelope and 

ductwork to provide appropriate insulation and proper air sealing. Table 22 is a chart describing 

their current building specifications. 

Table 22. Struever Rouse Standard Practice Specifications 

Foundation Walls R-11 fiberglass batts, half height, interior 

Rim/Band Joists R-13 fiberglass batts 

Exterior Walls 2x4, 16 in. OC, framed walls 

Wall Insulation R-13 fiberglass batts 

Floor System Open Web Trusses 

Windows Low-e, insulated glass w/ argon (U = 0.35, SHGC = 0.29) 

Ceiling Insulation Fiberglass Insulation (R-30) 

Duct System Designed by HVAC contractor, minimal duct sealing 

Transfer Grilles Only door undercuts 

Space Heating Two NG furnaces, 80% AFUE, atmospheric 

Space Cooling Two split-system air conditioners, SEER 13, R-22 refrigerant 

Thermostat Programmable 

Water Heating Gas water heater, EF = 0.61 

Lighting 10% Fluorescent 

Appliances StandardRefrigerator and Dishwasher 

Ventilation No mechanical control 

A detailed summary of several of the advanced technologies incorporated into the three 

prototype townhomes is discussed below. 

Engineered Panel System 

To increase the thermal resistance of the building envelope, CARB recommended switching 

from 2x4 framing to 2x6 framing. This Optimum Value Engineering (OVE) framing technique 

reduces the amount of lumber used to build a home while maintaining the structural integrity of 

the building. Using OVE results in lower material and labor costs and can also improve energy 

performance. OVE is a new technique for Struever’s panelizer. Though they were more than 

willing to make the framing modifications, they mistakenly spaced the 2x6 wood studs at 16 in. 

on center, rather than at 24 in. on center. This greatly reduces the cost and green benefits of 2x6 

wall construction. It still allows an increase in the thermal resistance of the building envelope, 

but it is not optimal. This spacing error resulted in a 7% increase in the overall U-value of the 

wall assembly. Because of the tight construction schedule, the panels could not be corrected for 

these prototypes. 

125 
High-Performance Insulation Strategy 

Air sealing the building envelope is a key part of 

reducing drafts and lowering the home’s energy 

use. Therefore, before installation of insulation 

into the stud cavities, low-expansion foam was 

used to air seal all stud cavities and between the 

bottom cord and subfloor. The use of foam at all 

seams significantly improves the air tightness of 

these homes (Figure 39). 

After the initial air sealing, a Blow-In-Blanket

® System 

(BIBS) was utilized to insulate the walls. Certainteed’s 

Optima® loose-fill fiberglass insulation was pneumatically 

blown behind non-woven Optima fabric (Figure 40). The 

compacted fiberglass provides a secondary air retarder. In 

addition, because the fiberglass insulation is manufactured 

from recycled glass, sand, and other ingredients, 

CertainTeed’s fiberglass insulation is GreenGuard 

certified. This certification helps identify products that 

have been tested for emissions of formaldehyde, volatile 

organic compounds (VOCs), respirable particles, and other 

pollutants. The net result of the R-21 blown insulation is a 

wall assembly that yields an R-value of 19 ft2-

o

F-hr/Btu — 

far superior to the R-13 fiberglass batts (net wall assembly 

R-value of 12 ft2-

o

F-hr/Btu) typically used in this 

development. 

For the basement, the insulation strategy was to use 2 in. 

of foil-faced polyisocyanurate rigid insulation (Thermax 

or equivalent product that is rated to be left exposed 

without a 15-min thermal barrier, such as 1⁄2-in. gypsum 

board) adhered to the upper half of the concrete 

foundation walls using low-emittance construction 

adhesive (Figure 41). With an insulating R-value of 7 ft

2

­ o

F-hr/Btu per in., this closed-cell insulation is better 

suited to moist basement conditions than standard 

fiberglass batt insulation. Because most of the heat loss is 

through the above-grade portion of the foundation, 

CARB is primarily concerned with insulating the top 4 ft Figure 41. Foil-faced 

of the foundation. Part of the rear portion of the walk-out polyisocyanurate rigid 

basement is framed construction, so the BIBS insulation insulation 

system was continued for that wall area. 

Figure 39. Low-expansion foam 

used to air seal stud cavities 

Figure 40. Blanket insulation 

126 
Figure 42. Insulating the box sills of all floors 

The final step of this insulation strategy was to insulate the box sills on all floors of the home 

with a closed-cell, two-component polyurethane spray foam Figure 42). This not only provides 

additional insulation, it helps to tightly seal all envelope penetrations and mitigates air and 

moisture problems in the rim and band joists. Bio-based products are available that meet the 

green goals of this project. The use of the spray foam at the box sills and blown-in wall 

insulation will further tighten up the envelope significantly. 

Energy Efficient HVAC 

To complement the highly insulated building envelope, the builder implemented a number of 

strategies for optimizing efficiency of the HVAC equipment and distribution system. 

HVAC in Conditioned Space 

Why is ductwork allowed to only be insulated up to R-6, when wall and ceiling insulation levels 

are R-13+ and R-30+, respectively? Ducts outside the building envelope are notorious leakage 

pathways, drawing in outside air and/or bleeding air that has been conditioned. As much as 20%­

35% of the energy supplied can be lost through a combination of air leakage and conduction 

when ducts are located in unconditioned spaces. This can also be a concern for indoor air quality, 

as these leakage pathways could pull in pollutants, irritants, or moisture from attics. 

To keep the ductwork within conditioned space, the HVAC equipment was properly sized 

according to Manual J and D calculations to allow for the most compact system possible. 

Oversized equipment results in larger ductwork and causes the system to cycle more frequently. 

Some design changes had to be made for the ductwork supplying the master loft. There is a 

corner knee wall in the loft where the mechanical equipment for the upper floors is located. This 

mechanical room was boxed in and air sealed to make it a part of the conditioned space. 

127 
In terms of a compact duct layout, registers were located toward the interior of the rooms. 

Eliminating long runs of ductwork has two benefits: energy efficiency increases and initial 

construction cost decreases. The use of open-web floor trusses also allow for easy, direct 

pathways to supply register locations. In this manner, all the ductwork was able to be integrated 

into the conditioned space with as minimal a footprint as possible. 

By maintaining the HVAC equipment and ductwork within the conditioned space, duct leakage 

to the outside should be minimal, if not negligible, especially because of the tight building 

envelope. To further minimize duct leakage, all duct connections were sealed with mastic to help 

prevent dust, soil, and other pollutants from entering the system. 

Mechanical Ventilation 

In conjunction with tightly sealing the envelope, the builder needs to provide controlled 

mechanical ventilation to ensure that the home has adequate fresh air to dilute pollutants and 

remove humidity from the home. 

CARB has recommended an “exhaust-only” strategy as the most appropriate solution for this 

project. This approach requires one bath fan in each of the homes be upgraded to a model that 

has been rated for: energy-efficient operation, continuous use, and quiet running. These three 

features are keys to the success of this strategy. An efficient fan will not be costly for the 

homeowner to operate. A fan rated for longer run times will not fail after a few months of 

operation. And lastly, the homeowner is less likely to disable the fan if it runs quietly. 

The fan is partnered with a timer control, which turns the fan on for set periods throughout the 

day. This ventilation system complies 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 Low-rise Residential Buildings. The upgraded bath fan 

should be wired to allow occupant control via a manual override switch within the bathroom. 

The timer switch should also be tied into the fan wiring and remote-wired to a nearby closet to 

prevent tampering. 

All other bathrooms and the kitchen range should still have exhaust fans for local humidity 

control. CARB requires that all exhaust fans be vented directly to the outside (no recirculating 

kitchen exhaust fans). 

Return Air Pathways 

To allow for a more compact duct design and improved system balance, central return ducts were 

positioned close to the air handlers. Pressure imbalances, such as those caused by closed 

bedrooms doors with inadequate door undercuts, cause the HVAC system to work harder than it 

should. This drops equipment efficiency and can lead to compromised comfort and health. 

Transfer grilles with a sound/light baffle were installed over the doors of the secondary 

bedrooms, to reduce pressurization of those spaces and mitigate comfort and moisture concerns. 

Centralized returns save material cost and energy without compromising performance. 

128 
Additional Features 

To complement the energy-efficient elements utilized in these townhomes, “green” components 

were also considered to reduce the overall environmental footprint of these units. Additional 

features that were incorporated into this project are listed below: 

• No- or low-VOC paints, caulks, sealants, and adhesives 

• Formaldehyde-free fiberglass (GreenGuard certified) and polyisocyanurate insulation 

• Bamboo flooring 

• Wool carpet with recycled content padding 

• Green lighting package (fluorescent lighting fixtures) 

• Low-flow fixtures and dual-flush toilets 

• Ultra-light trim made from recycled wood 

• Kitchen composters 

• Kitchen recycling bins 

• Media Air Cleaner (HEPA filtration) 

• Whole-house carbon filters. 

Overall Building Specification 

Table 23 summarizes the building specifications for the three prototype townhomes. 

Table 23. Struever Rouse Prototype Specifications 

Foundation Walls 2-in. Polyiso, foil-faced rigid insulation board (R-14), half height, interior 

Rim/Band Joists Spray-in-place polyurethane foam insulation (R-6.75/in.) 

Exterior Walls 2x6, 24 in. OC, framed walls 

Wall Insulation Certainteed Optima Blown-In Fiberglass Insulation (R-21) 

Floor System Open Web Trusses 

Windows Milgard IG low-e, argon-filled (U = 0.35, SHGC = 0.29) 

Ceiling Insulation Certainteed Optima Blown-In Fiberglass Insulation (R-40) 

Duct System Compact System sealed with Mastic (designed by HVAC contractor) 

Transfer Grilles R.A.P. Transfer Grilles, 8 in x 8 in. over the doors of each secondary bedroom 

Space Heating Two Goodman GMS9045 gas furnaces, 93% AFUE, direct vent 

Space Cooling Two Goodman GSC13 air conditioners, SEER 13 

Thermostat Programmable 

Water Heating Noritz tankless gas water heater, EF = 0.82 

Lighting 100% Fluorescent, specified by Struever Rouse & reviewed by CARB 

Appliances ENERGY STAR®

 Refrigerator and Dishwasher 

Ventilation Upgraded ENERGY STAR®bath fan controlled by Grasslin Pin Timer 

129 
Energy and Cost Information 

Home Energy Performance 

CARB determined that the energy performance of the current builder home is 17% better than 

the Building America Benchmark Home (Hendron 2005). Once this “standard practice” energy 

performance was established, CARB simulated the impact of alternative specifications on the 

energy performance of the home. CARB felt the most effective approach for saving energy and 

lowering operating costs involved an integrated package of upgrades to the mechanical 

equipment and building envelope. Struever Rouse’s standard specifications for the windows and 

furnace were acceptable for meeting the target energy goals. 

CARB recommended increased insulation levels, improved air sealing, location of all the 

ductwork within the conditioned space, and “on-demand” water heating. To help further reduce 

electrical loads, 100% of the lighting was fluorescent fixtures and the builder will provide both 

an ENERGY STAR® refrigerator and dishwasher. When implemented, this package provided a 

total annual source energy savings of 36%, as shown in Table 24. 

Table 24. Energy Savings for Frankford Estates Plan C 

Struever Rouse - Frankford Estates Plan C 

Summary of Energy Consumption by End-Use 

Annual Site Energy Annual Site Cost 

kWh Therms 

Benchmark 

kWh Therms 

Builder 

kWh Therms 

Prototype Benchmark 

$ 

Builder 

$ 

Prototype 

End-Use $

Space Heating 576 802 604 664 323 385 $ 709 $ 597 $ 344 

Space Cooling 2267 0 1528 0 1162 0 $ 171 $ 116 $ 88 

DHW 0 235 0 202 0 152 $ 195 $ 168 $ 126 

Fixed Lighting 1959 1959 726 $ 148 $ 148 $ 55 

Appliances 1815 45 1815 45 1727 45 $ 175 $ 175 $ 168 

Plug Load 3273 3273 3273 $ 247 $ 247 $ 247 

Plug-in Lighting 405 405 405 $ 31 $ 31 $ 31 

OA Ventilation 196 210 124 $ 15 $ 16 $ 9

Total Usage 10491 1082 9794 911 7741 582 $ 1,691 $ 1,497 $ 1,068 

Site Generation 

Net Energy Use 10491 1082 9794 911 7741 582 $ 1,691 $ 1,497 $ 1,068 

Summary of End-Use Source-Energy and Savings 

Benchmark Builder Proto Builder Prototype Builder Prototype Builder Prototype 

End-Use MBtu/yr MBtu/yr MBtu/yr 

Space Heating 88.0 74.2 42.8 16% 51% 6% 20% 55.1% 56.1% 

Space Cooling 24.4 16.5 12.5 33% 49% 4% 5% 32.0% 14.8% 

DHW 24.0 20.6 15.5 14% 35% 2% 4% 13.5% 10.5% 

Fixed Lighting 21.1 21.1 7.8 0% 63% 0% 6% 0.0% 16.5% 

Appliances 24.2 24.2 23.2 0% 4% 0% 0% 0.0% 1.2% 

Plug Load 35.3 35.3 35.3 0% 0% 0% 0% 0.0% 0.0% 

Plug-in Lighting 4.4 4.4 4.4 0% 0% 0% 0% 0.0% 0.0% 

OA Ventilation 2.1 2.3 1.3 -8% 36% 0% 0% -0.6% 1.0% 

Total 223.4 198.5 142.8 11% 36% 11% 36% 100% 100% 

Site Generation 0.0 0% 0% 

Net Energy Usage 223.4 198.5 142.8 11% 36% 11% 36% 

Source Energy Savings 

Annual Source Energy Percent of End-Use Percent of Total Component % 

The "Percent of End-Use" columns show how effective each building is in reducing energy use over the Benchmark in each end-use category.

 The "Percent of Total" columns show how the energy reductions in each end-use category contribute to the overall savings. 

energy costs $0.0756 /kWh for electricity Baltimore Gas & Electric 

$0.83 /therm for natural gas Maryland Average 

130 
Field Inspection 

During the inspection of the mechanical rough-in of the initial townhouse, CARB observed the 

usage of pressure-sensitive aluminum foil tape to seal the intersection of the flex ducts to the 

sheet metal ductwork (Figure 43). Using an aluminum-backed butyl tape that is UL-181 A/B 

rated is acceptable, but CARB has found that the application of mastic to seal ductwork is easier, 

faster, and more economical. Either way, the current sealing was being done with a non-UL-181 

rated product. The HVAC contractor switched to mastic for sealing the ductwork, but it took 

another CARB site visit before the mastic was being properly applied to achieve the tight 

ductwork that was required. 

Figure 43. Using pressure-sensitive aluminum foil tape and mastic to seal 

intersections of ducts 

A situation in which various trades are working on the single installation resulted in a 

mechanical ventilation concern (Figure 44), which is a common occurrence in residential 

construction. Rather than rotating the pre-installed ventilation fan enclosure 180°, the HVAC 

contractor simply vented the fan using an 180° bend in the exhaust vent ductwork. This adds an 

unnecessary pressure drop to the system and leads to decreased exhaust ventilation capacity. 

Figure 44. Improperly installed ventilation fan 

131 
A common area that is missed when insulating the building envelope is the fireplace bump out. 

CARB ensured that the enclosure was fully insulated before installation of the direct vent 

fireplace. This area is commonly missed because it is not readily accessible (Figure 45). 

Figure 45. Fireplace bump outs are frequently missed when insulation is 

installed 

Cost 

Based on the cost-benefit analysis and local market drivers, Struever Rouse Homes is likely to 

incorporate many of the building strategies recommended by CARB into their standard builder 

package. This package would include 2x6 panelized wall systems (24 in. o.c.) with BIBS, a 

tankless water heater, high efficiency furnace, and controlled mechanical ventilation. The 

recommended CARB improvements not only provide annual energy savings, but also work with 

Struever Rouse Homes focus on healthy and sustainable living. 

Table 25 shows the estimated incremental costs for the energy efficiency measures used in this 

project. In production scale, several of these costs would be lower than were priced out for these 

prototypes. For one, the 2x6 (24 in. o.c.) wall panels use essentially the same board-feet of 

lumber as 2x4, 16 in. on-center panels, but because of the error of spacing the 2x6 studs at 16 in. 

on center, there was around a 70% price increase for the panels as a result of the increased 

lumber usage. 

Follow-On Activities 

Struever Rouse Homes has given a preliminary commitment to follow up on this project in 2007 

with a 75-unit community in Baltimore at the 30% performance level. 

Table 25. Summary of Incremental Costs for Energy Improvements 

Incremental Cost Increase 

Building Component Lot 152 Lot 153 Lot 154 Improvement 

Appliances 

Electric 

Energy Star 

HVAC 

Insulation 

 Plumbing 

Poured Walls 

Wall Panels 

$591 

$1,204 

$500 

$2,880 

$1,795 

$950 

$566 

$3,662 

$591 

$1,204 

$500 

$2,930 

$535 

$950 

$837 

$2,945 

$591 

$1,204 

$500 

$2,880 

$1,795 

$950 

$566 

$3,662 

Energy Star dishwasher and refrigerator 

Fluorescent lighting package, ventilation timer 

air sealing 

92 AFUE furnace, Energy Star ventilation fan, transfer grilles, Puron A/C 

BIBS, basement rigid insulation, rim/band foam

tankless water heater, dual flush toilet 

thicker foundation wall due to 2x6 framing 

2x6 framing (but at 16"o.c.) 

total $12,148 $10,492 $12,148 

total w/o panels $8,486 $7,547 $8,486 

132 
Figures 46, 47, and 48 show the floor plans for the townhouses. 

Figure 46. Basement plan 

133 
Figure 47. First-floor plan 

134 
Figure 48. Second-floor plan 

135 
Development: Grove Park 

Builder: Outlook Construction 

Location: Cartersville, Georgia 

Background 

Beginning in early 2003, the Consortium for Advanced Residential Buildings (CARB) began 

working with Outlook Construction near Atlanta, Georgia, to investigate cost-effective 

performance improvements to its line of affordable homes. Outlook, located in Cartersville, 

Georgia, is a regional builder that builds about 200 homes a year (Figure 49). They are a relative 

newcomer to affordable production, having begun business as a custom builder. Before CARB’s 

involvement, Outlook management had embarked on a program of highly effective building 

envelope initiatives working closely with K.E.S. Insulation, also of Cartersville. The result of 

that prior work was the development of a very tight and well-insulated standard practice wall 

system composed of 2x6 framing at 24 in. on-center, R-3 XPS foam sheathing, a 1⁄2-in. skim of 

polyurethane foam placed on the interior of the sheathing as an air-barrier, and damp-sprayed 

cellulose to fill the cavity. 

Starting with solid envelope specifications and a good understanding of building science, 

Outlook approached CARB in order to get to the next level. CARB worked closely with 

Outlook, KES Spray Insulation, and Meadows Heating and Air to understand the company’s 

needs and to help them achieve the next level of market separation from their competitors. This 

work has focused on improvements to the HVAC system, refining the insulation and air-sealing, 

and assisting in further implementing advanced framing techniques and other cost-saving 

measures. 

Based on the success of this initiative, Outlook asked CARB for assistance in designing, 

engineering, and specifying equipment for a new 120-unit development called Birchwood Farms, 

by far the largest project Outlook had been involved with to date. In Birchwood Farms, located 

approximately 45 minutes north of Atlanta, Outlook wanted to improve upon their standard highperformance homes to achieve 1999 HERS scores above 89. 

The Birchwood subdivision featured five home models ranging from 1,450 ft2 to 2,100 ft2. The 

smallest home, the Abigail is a three-bedroom slab-on-grade ranch, the other homes are either 

raised ranches (split-level entry) or true split-levels. All lower levels in these homes are provided 

unfinished. 

As a follow-up, Outlook requested CARB’s assistance once again in 2004 on their new 103-unit 

Grove Park development. This subdivision would focus on larger two-story homes in the 2,000­

3,000-ft2 range. Located in Cartersville, Georgia, these homes are two-story, slab-on grade 

detached houses with attached two-car garages. All homes were to meet the 30% Building 

America total source-energy savings goal. Because of utility incentives that distorted the local 

market, several of the homes did not meet this annual source energy-savings goal, but this is 

discussed later. 

136 
Figure 49. Home in Cartersville, Georgia 

Performance verification was done on the Vineyard (Big A-1 floor plan) and Bay Point (Plan C 

Alley floor plan) model homes as they represent the two most common models in the 

development (Figures 50 and 51). 

Figure 50. Vineyard and Bay Point model homes 

137 
Figure 51. Layout of Grove Park 

Advanced Technologies 

Design considerations for Outlook Construction primarily focused on the building envelope and 

ductwork to provide appropriate insulation and proper air sealing. Below is a summary of several 

of the advanced technologies incorporated into the Grove Park development. 

Engineered Panel System 

The 2x6 panelized open wall system used for the exterior structure helps to contribute to overall 

quality and tightness of the home. The panels are assembled off-site in a controlled environment 

with finer tolerances and higher quality than are typically possible with field construction. 

Fabrication is based on detailed shop drawings generated from the home design. 

During design, the location of window and door openings is coordinated with Outlook’s standard 

panel length of 12 ft to minimize the number of studs. While panels are available in longer 

lengths, the builder finds benefits to working with a standard unit size. Most importantly, the 

138 
12-ft. panels used by Outlook can easily be erected by framing crews and do not require a crane 

for installation. 

The panelized wall system helped Outlook Construction increase jobsite productivity, reduce 

project cycle time, reduce jobsite waste, and enhance construction quality, including the quality 

of interior and exterior trim and finishes. 

The panels were engineered using Optimum Value Engineering (OVE) framing principles. The 

OVE framing technique reduces the amount of lumber used to build a home while maintaining 

the structural integrity of the building. Using OVE results in lower material and labor costs and 

can also improve energy performance. OVE strategies used for this development include the 

following: 2x6 wood framing, 24 in. on-center framing, ladders at “T” intersections, open-corner 

framing, and right-sized headers. 

High-Performance Insulation Strategy 

As a builder of ENERGY STAR® Homes, Outlook actively pursues new technologies for 

creating a highly efficient building envelope. The project team explored various insulation 

techniques in different housing assemblies to determine optimum methods for insulating the 

panelized walls. The energy-saving insulating strategies that were used are described here in 

detail. 

Foam Insulation Skim-Coat on Wall Panels. Outlook Construction joined with KES Insulation 

to develop a unique and highly effective two-step insulation process. In the first step a 1⁄2-in. 

layer of polyurethane is sprayed into a wall’s stud cavity, creating a sealed space and air barrier. 

The layer of 2 lb. closed-cell foam doubles as a vapor retarder placed to the exterior of the 

insulation, an ideal location for homes built in hot and humid climates. Spraying polyurethane at 

the band joists is another insulation method KES uses for additional sealing. 

Spray-Applied Cellulose Insulation. In the second step of the wall insulation process, cellulose 

insulation is damp-sprayed into the remaining 5-in. stud space. Cellulose is made of recycled 

products (such as newspaper) and provides an excellent thermal barrier. When the damp mix is 

sprayed on, interlocking fibers in the cellulose form a continuous coating that seals cracks or 

openings, eliminating voids, and providing an excellent noise barrier. The combination of foam 

and cellulose yields R-23 wall insulation values—far superior to the R-13 fiberglass batt 

insulation typically found in the Atlanta region. 

Energy Efficient HVAC 

CARB performed energy modeling to pinpoint opportunities for energy efficiency 

improvements. To complement the highly insulated building envelope, the builder implemented 

a number of strategies for optimizing efficiency of the HVAC equipment and distribution 

system. 

Air Handler in Conditioned Space. Working with the designers, a mechanical closet was 

located within the house, which allows the air handler(s) for the heat pump(s) to be within 

conditioned space. This represents a significant improvement over the traditional practice of 

placing equipment in unconditioned garages or attics. Locating the mechanical equipment within 

conditioned space greatly improves operating efficiency and protects indoor air from 

contaminants that may be present in unconditioned areas. 

139 
o

F-hr/Btu to be achieved with conventional R-4.2 ft2-

o

F-hr/Btu 

Figure 52. Insulating ducts with closed-cell 

polyurethane foam 

Compact Duct Layout. For the compact duct layout design, registers are located on interior 

corners of rooms closer to the air handler. Eliminating long runs of ductwork has two benefits: 

energy efficiency increases and initial construction cost reductions. Utilizing a centralized return 

also saves on material cost and energy without compromising performance. 

Foamed-over Ducts. Leaky 

and poorly insulated ducts 

can add 20%-40% to a 

homeowner’s heating and 

cooling costs. CARB 

recommended a two-part 

approach to achieve optimal 

energy performance from 

ducts located in the vented 

attic. First a 1-in. layer of 

2-lb. closed-cell 

polyurethane foam was 

applied to the ductwork to 

boost R-values, control 

condensation, and provide 

additional air sealing (Figure 

52). The application of 1­

in.of this spray foam 

increases duct R-value by 7 

ft2-

o

F-hr/Btu, allowing a 

duct system R-value of 11 ft2­

duct wrap. 

One important advantage of the foam is that it minimizes the likelihood of condensation when 

ductwork is buried in the attic insulation. The dew point will be located within the foam 

insulation layer, which is a vapor barrier. In addition, the closed-cell foam helps air seal the 

ductwork. Foam has the advantage of being easier to apply in hard-to-reach places. The airsealing properties are especially beneficial around registers that penetrate the ceiling (an area that 

is typically prone to leakage). 

Buried Ducts. Foamed-over ducts perform optimally in conjunction with a second energysaving technique: ductwork buried under attic insulation (Figure 53). Burying the ducts under 

blown-in cellulose insulation minimizes losses from distribution of conditioned air. Ideally 

ductwork should be placed directly on the gypboard or the bottom chords of the roof trusses; 

however, sections occasionally need to be lifted above the insulating layer in order to coordinate 

with the truss webs. The increase in duct system R-value because of burying ducts in loose fill 

attic insulation depends on the depth of burial. 

While buried ducts work well to save heating and cooling energy in any climate, the blown 

insulation alone does not prevent condensation problems in hot, humid climates. When heat and 

moisture are prevalent, buried ducts used together with sprayed-on foam yield the best result. 

140 
Cellulose insulation 

Closed -cell foam insulation 

Mastic -sealed duct 

Figure 53. Foamed-over ducts buried in attic insulation 

Overall Building Specification 

Table 26 summarizes the building specifications for the two primary Grove Park model types 

and the Building America Benchmark reference house (Version 3.1). 

141 
Table 26. Features of Grove Park Models Compared to the Benchmark 

Characteristic Benchmark Home Vineyard Prototype Bay Point Prototype 

Slab Construction poured slab poured slab poured slab 

Slab Insulation R-4 (2 ft perimeter) -- --

Framed Floor Construction 9 1/2" I-joist @ 16" o.c. 9 1/2" I-joist @ 16" o.c. 9 1/2" I-joist @ 16" o.c. 

Framed Floor Assembly U-0.05 R-26 batt insulation R-26 batt insulation 

Wall Construction: 1st Floor 2x6 wood framing - 16" o.c. 2x6 wood framing - 24" o.c. 2x6 wood framing - 24" o.c. 

Wall Assembly: 1st Floor U-0.076 R-20 blown insulation / R-3 

foam 

R-20 blown insulation / R-3 

foam 

Garage Interior Wall Const. 2x6 wood framing - 16" o.c. 2x6 wood framing - 24" o.c. 2x6 wood framing - 24" o.c. 

Garage Interior Wall Assembly U-0.076 R-20 blown insulation R-20 blown insulation 

Ceiling/Roof Construction wood trusses @ 24" o.c. wood trusses @ 24" o.c. wood trusses @ 24" o.c. 

Ceiling Assembly U-0.036 R-38 insulation R-38 insulation 

Window Type benchmark vinyl double low-e vinyl double low-e 

Window U-Value 0.65 0.36 0.36 

Window SHGC 0.58 0.33 0.33 

Interior Shading 

interior shading multiplier = 0.7 in 

cooling season and 0.85 in heating 

season 

interior shading multiplier = 0.7 in 

cooling season and 0.85 in heating 

season 

interior shading multiplier = 0.7 in 

cooling season and 0.85 in heating 

season 

Doors U-0.20 U-0.40 U-0.40 

Infiltration 0.47 natural ACH 1473 cfm50 (0.31 ACHnat) 3170 cfm50 (0.47 ACHnat) 

Heating System 

Gas Furnaces 

78 AFUE 

Gas Furnace / (Heat Pump) 

80 AFUE / (6.8 HSPF) 

(2) Gas Furnace 

80 AFUE 

Cooling System 

Air Conditioners 

SEER 10 

Air Conditioner / (Heat Pump) 

SEER 12 / (SEER 12) 

(2) Air Conditioner 

SEER 12 

Water Heater 

Gas Water Heater 

EF 0.54 

Gas Water Heater 

EF 0.59 

Gas Water Heater 

EF 0.59 

HW Tank Size 40 gals 40 gals 40 gals 

Water Heater Location garage garage garage 

Duct R-value R-5.0 R-3 foamed over ducts R-3 foamed over ducts 

Supply Duct Location 100% attic 100% attic 50% attic 

Return Duct Location 100% attic 100% garage 50% attic 

AHU Location interior garage mechanical closet 

Duct Leakage to Outside 11.5% 

downstairs: 44 cfm25 / upstairs: 

52 cfm25 

downstairs: 72 cfm25 / upstairs: 

78 cfm25 

Leakage Fraction return:33% return:30% / AHU:5% return:10% / AHU:5% 

mechanical ventilation -- -- --

-- -- --

Programmable Thermostat? no yes yes 

Temperature 

cooling: 78o

F cooling: 78oF (81oF) cooling: 78oF (81oF) 

heating: 68oF heating: 68oF (63oF) heating: 68oF (63oF) 

Lighting 10% fluorescents 0% fluorescents 0% fluorescents 

Energy Star Appliances -- refrigerator, dishwasher refrigerator, dishwasher 

142 
Energy and Cost Information 

Home Energy Performance 

Figure 54. Park Grove models 

CARB performed a number of tests to evaluate energy performance of the Grove Park prototype 

homes (Figure 54). Building tightness, duct leakage, and balance of the air-distribution system 

were quantified. These elements were incorporated into the energy simulation to determine the 

percentage improvement over the Building America Benchmark. Table 27 shows the estimated 

annual performance of the Vineyard and Bay Point prototype models versus the Benchmark. The 

values in the Benchmark column refer to the reference home for the Vineyard and Bay Point 

models, respectively. The initial Bay Point model did not meet the 30% total energy savings goal 

over the Building America Benchmark home. Reasons for this will be discussed later. There is 

also a final row showing the potential energy savings if all CARB recommendations were 

incorporated. 

Not all projects go as planned. The real story about the heating systems is that CARB initially 

recommended two heat pumps (upstairs and downstairs) for each home, but local gas utility 

incentives distort the market by making the builder use gas as the main heat and hot-water fuel in 

exchange for “free” gas infrastructure in the development. Based on the gas incentives the 

builder switched to 80% furnaces for the first (main) floor and heat-pumps or furnaces for the 

upper floor. CARB intervened with the builder and convinced them to switch to the 92% 

condensing furnaces (not the norm for this market) for efficiency and, equally important, indoor 

combustion, air-quality, and pressure-balance reasons. The HVAC subcontractor agreed to install 

the 92% units with no additional cost mark-up for the remaining Grove Park build out. 

143 
-

Table 27. End-Use Energy Consumption for Grove Park Prototypes 

Summary of Energy Consumption by End-Use 

Annual Site Energy Annual Site Cost 

kWh Therms 

Benchmark (Vineyard/Bay Point) 

kWh Therms 

Vineyard Prototype 

kWh Therms 

Bay Point Prototype Benchmark 

$ 

Vineyard 

$ 

Bay Point 

End-Use $

Space Heating 899 / 288 407 / 411 158 223 90 132 346 / 301 164 97 

Space Cooling 5016 / 5797 0 1401 0 3640 0 391 / 452 109 284 

DHW 

Lighting 

0 

2422 / 3057 

221 / 240 0 192 0 209 150 / 163 130 142 

2619 3217 189 / 238 204 251 

Appliances 2419 / 2610 0 2230 0 2409 0 188 / 203 174 188 

Plug Load 3375 / 4701 3375 4701 263 / 366 263 366 

OA Ventilation 0 0 0 0.0 0 0 

Total Usage 14131 / 16453 628 / 651 9783 415 14057 341 1527 / 1723 1043 1326 

Site Generation 0 0 

Net Energy Use 14131 / 16453 628 / 651 9783 415 14057 341 1527 / 1723 1043 1326 

Recommended Prototype* 7562 296 11113 228 1020 

Summary of End-Use Source-Energy and Savings 

Benchmark Vineyard Bay Point Vineyard Bay Point Vineyard Bay Point Vineyard Bay Point 

End-Use MBtu/yr MBtu/yr MBtu/yr 

Space Heating 51.2 / 45.0 24.4 14.4 52% 68% 12% 13% 39% 53% 

Space Cooling 54.1 / 62.5 15.1 39.2 72% 37% 18% 10% 57% 40% 

DHW 22.5 / 24.5 19.6 21.3 13% 13% 1% 1% 4% 6% 

Lighting 26.1 / 33.0 28.2 34.7 -8% -5% -1% -1% -3% -3% 

Appliances 26.1 / 28.1 24.0 26.0 8% 8% 1% 1% 3% 4% 

Plug Load 36.4 / 50.7 36.4 50.7 0% 0% 0% 0% 0% 0% 

OA Ventilation* 0.0 0.0 0.0 0% 0% 0% 0% 0% 0% 

Total 216 / 244 148 186 32% 24% 32% 24% 100% 100% 

Site Generation 0 0 

Net Energy Usage 216 / 244 148 186 32% 24% 32% 24% 

Recommended Prototype* 112 143 48% 41% 48% 41% 

Source Energy Savings 

Annual Source Energy Percent of End Use Percent of Total Component % 

*Recommended Prototype includes all of CARB's recommendations 

Notes: The "Percent of End-Use" columns show how effective each building is in reducing energy use over the Benchmark in each end-use category. 

The "Percent of Total" columns show how the energy reductions in each end-use category contribute to the overall savings. 

energy costs $0.0779 /kWh for electricity Georgia Power Co. 

$0.68 /therm for natural gas Georgia Average 

equipment sizing 

Benchmark 54.5 / 59.5 kBtu/hr for heating 

55.1 / 56.2 kBtu/hr for sensible cooling --> 7.0 nominal tons 

Vineyard Prototype 32.9 kBtu/hr for heating 

20.7 kBtu/hr for sensible cooling --> 2.5 nominal tons 

Bay Point Prototype 42.8 kBtu/hr for heating 

32.8 kBtu/hr for sensible cooling --> 4.0 nominal tons 

1999 HERS 

Benchmark 80.4 / 81.2 

Builder 90.4 

Prototype 90.0 

Advanced 93.3 / 92.5 

*Sizing of cooling nominal tons is based on a SHR of 0.7, 0.75, 0.75, respectively 

144 
Field Inspection 

In the Vineyard model, the 

mechanical room access is 

from the garage (Figure 55). 

The wall between the garage 

and the mechanical 

room/interior is insulated. 

The intent was to place the 

mechanical equipment in 

conditioned space. With the 

use of atmospheric furnaces, 

the mechanical room 

requires make-up air that 

was achieved by having a 

louvered door. This now 

makes the mechanical room 

unconditioned. Therefore, all 

the interior walls of the 

mechanical room and the 

chase above need to be 

insulated. The foyer, kitchen, 

laundry room, upstairs 

hallway, and front bedroom 

are all adjacent to this 

mechanical room. If 

atmospheric furnaces were to 

be used, then these interior 

walls would need to be 

insulated. This also raised 

the concern of the air 

handlers drawing garage 

gases into the living space. 

In the Bay Point model, 

because of the use of 

atmospheric equipment, an 

8-in. duct to the attic is 

installed to provide make-up 

air. First of all, when ducting 

air into the mechanical room, 

there should be a high and 

low register in the 

mechanical room. The 

reason for this is that the 

“two openings will induce a 

Figure 55. Layout of Vineyard model 

145 
convective air current in the room by admitting cooler, more dense air in the lower opening and 

allowing the escape of warmer, less dense air through the upper opening (1998 International 

Mechanical Code).” Regardless, a louvered door should not have been installed between the 

mechanical room and the living space. The use of the louvered door provides a direct path for 

unconditioned air to enter the building envelope or for conditioned air to be lost to the exterior. 

Another concern that was found during the performance testing was the lack of a proper return 

air pathway for the master suite. A room-by-room pressure diagnostic was performed to see if 

the central returns would be adequate. With only a central return in the upstairs hallway, a 

noticeable pressurization of the bedrooms was observed when doors were closed. The Master 

Suite (which includes the Master Bedroom, Master Bath, and WIC) saw a pressure increase of up 

to 18 Pa when the door to the hallway was closed during the cooling mode. This is a significant 

pressure difference that will lead to a reduction in HVAC performance and also could be 

noticeable by the homeowner (comfort issue). The secondary bedrooms were also pressurized 

when doors were closed, though not as significantly. The use of jumps ducts, rather than just 

door undercuts, would eliminate this issue. 

Recommended Improvements 

CARB continued to work with Outlook Construction to make improvements to their building 

specifications. The primary change, which Outlook agreed to, was to upgrade the Bryant gas 

furnaces from the Plus 80 models to the Plus 90 models. Switching to sealed-combustion 

furnaces reduces heating costs and also allows for the removal of the outdoor make-up air to the 

mechanical room. By making the mechanical room part of the interior conditioned space, the 

building envelope will be tighter and duct leakage to the outside is minimized. When only the 

improved AFUE of the sealed-combustion furnace (minimum AFUE of 92) is considered, there 

the heating fuel usage reduced by 12%-13%, depending on the house model. If improvements in 

the infiltration and duct leakage to the outside are considered, there will be even more substantial 

savings. For modeling purposes, an estimated annual natural infiltration rate of 0.15 ACH (value 

seen in a previously tested Outlook prototype, Cooper 2) was applied, along with switching the 

mechanical room to interior space and a duct leakage to outside of only 3%. This results in a 

heating savings between 32% and 44% and cooling savings of from 14% to 16% annually. 

The other atmospheric equipment that is present is the water heater. Though this could be 

improved simply by upgrading to a direct-vented water heater (EF 0.62), CARB has been 

recommending switching to a tankless “on-demand” gas water heater (EF 0.82). This would 

result in a savings of 33%-37% on hot water fuel usage. 

The last major specification that CARB continues to discuss with Outlook Construction is the 

design of a compact fluorescent lighting (CFL) package. Switching to a fluorescent lighting 

package would reduce lighting electrical consumption by two-thirds. This will also provide 

savings as a result of the lower cooling load. 

The net benefit of these added efficiency measures would be a total annual source-energy 

savings of 41%-48% compared to the Building America Benchmark. 

146 
Cost 

As a small volume regional production builder, Outlook Construction remains flexible and 

adaptive and is able to quickly integrate new products and techniques into their custom and 

production homes. Many of the techniques endorsed by CARB have been successfully integrated 

into production and have become standard practice. These include panelized wall systems, 

advanced 24-in. on-center framing, open-web floor trusses, polyurethane-foam skim-coated stud 

cavities, low-e windows, down-sized HVAC, compact HVAC distribution, and others. 

The net cost increase for these various improvements is minimized through integrated design, 

production efficiencies, and cost trade-offs. The 2x6 wall panels use essentially the same boardfeet of lumber as 2x4, 16-in. on-center panels, while the panelization process raises production 

by expediting the framing process and reducing waste. Other improvements, such as the low-e 

windows were adopted by Outlook before the Georgia energy code requirement going into 

effect. CARB provided the engineering documentation and subsequent testing to assure Outlook 

that this change allows for a substantially reduced HVAC system essentially negating the 

increased cost for those windows. 

The foamed-over buried ducts similarly have a net-zero cost implication as a result of further 

HVAC down-sizing. For comparison’s sake, the insulator estimated the cost to foam the ducts at 

approximately $350 when done on a production scale. Insulating the exterior wall with a foam 

skim-coat and 5 in. of damp-spray cellulose constituted the only substantial cost increases. 

Of the CARB-inspired specification changes incorporated, only one has not been refined to the 

point of full implementation: foamed-over buried ducts. The reason for the ducts is two-fold: a 

production process in which it is currently simpler to foam the ducts before the installation of the 

ceiling gypsum board and the use of standard (Howe) trusses rather than the use of Warren 

trusses. The use of the Warren truss would allow for better placement of the ducts directly on the 

attic floor, hence providing more uniform insulation burial. CARB has since met the builder and 

the truss fabricator to adopt these changes to more effectively implement the buried duct 

strategy. 

The floor plans are shown in Figures 56, 57, 58, and 59. 

147 
Figure 56. Vineyard floor plan (second floor) 

148 
Figure 57. Vineyard floor plan (first floor) 

149 
Figure 58. Bay Point floor plan (second floor) 

150 
Figure 59. Bay Point floor plan (first floor) 

151 
Development: Valencia 

Builder: Ideal Homes 

Location: Oklahoma City, Oklahoma 

Figure 60. Ideal Homes high-efficiency home near Oklahoma City 

Ideal Homes builds developments of high-efficiency homes in the Oklahoma City area, aimed at 

various price points from modest to custom (Figure 60). They have incorporated several energy 

upgrades into their standard product and continue to reach for higher efficiency goals with 

special projects. As they learn from the special projects, they work to include the improved 

technology into their standard production. At this point, the standard houses use insulating 

sheathing, slab-edge insulation, air sealing of the framing at connection points, draft stops behind 

tubs and fireplaces, low-E glazing, 90+% AFUE furnaces, and 14 SEER cooling systems with 

low leakage ducts. With these upgrades, they are able to reach into the 30% overall savings range 

(Figure 61). 

Table 28 summarizes the key specifications for the Ideal Homes project. 

152 
Figure 61. Ideal Homes section detail 

153 
Table 28. House Specifications 

Building envelope 

Ceiling R-30 blown cellulose at ceiling 

Walls R-15 + R-3 insulating sheathing 

Foundation Slab, R-4 interior insulation 

Windows Double Glazed Vinyl Frame Low-E2 

U = 0.39, SHGC = 0.31 

Infiltration 2.5-in2

 leakage area per 100 ft

2

 envelope 

Mechanical systems 

Heat 90% AFUE Gas furnace 

Cooling 14 SEER A/C unit 

DHW 0.59 EF gas tank in garage closet 

AHU location in vented attic 

Ducts In vented attic, R-6 insulation 

Leakage 5% or less 

Supply-only system integrated with AHU 

Per ASHRAE 62.2 46 CFM continuous 

Ventilation average flow 

Lighting 90% incandescent lighting 

Appliances & Plug ENERGY STAR Appliances 

154 
Parametric Study 

Figure 62 charts overall source energy use reduction and shows that the cooling and lighting 

loads are greatly diminished with the recommended improvements. Table 29 summarizes the 

results in tabular form. 

Ideal Homes, OKC Plan 1451 Community Specs Parametrics 

0 

50 

100 

150 

200 

250 

MM

Btu/yr . 

Heating Cooling Hot Water Lighting Appl & Other 

Benchmark Envelope Upgrade Mechanical Upgrade Light & Appliance 

Upgrade 

Figure 62. Overall source energy use reduction 

Table 29. Tabular Summary of Parametric Study 

Estimated 

Parametric Individual 

Run ID Description of change Cost of change 

Estimated 

Cumulative 

Cost of change 

Total Source Energy Savings

 (H/C/DHW/Lights/Appliances/Plug) 

over BA Incremental Annual Item Simple Increment 

Benchmark1 Over Bmrk energy cost Savings payback (yr) payback (yr) 

30% Communities 

20 Benchmark n/a n/a n/a n/a $1,395 n/a n/a n/a 

21 20 + Envelope Upgrade $1,000 $1,000 15.3% 15.3% $1,193 $202 5 5 

22 21 + Mechanical Upgrade $1,200 $2,200 27.4% 12.1% $1,005 $188 6 6 

23 22 + Light & Appliance Upgrade $1,000 $3,200 36.2% 8.9% $867 $138 6 7 

155 
-

-

Source Energy Consumption Summary 

Note that the “Percent of End-Use” column shows how effective the prototype building is at 

reducing energy use in each end-use category; the “Percent of Total” column shows how the 

energy reductions in each end-use category contribute to the overall savings (Table 30). 

Table 30. Source Energy Savings for Ideal Homes 

% of End Use % of Total 

BA Benchmark Prototype 1 Prototype 1 Prototype 1 

End Use 106 BTU/yr 106 BTU/yr Savings Savings 

Space Heating 65 40 38% 12% 

Space Cooling 46 19 59% 13% 

DHW 27 24 10% 1% 

Lighting 23 7 70% 8% 

Appliances + Plug 46 42 9% 2% 

Total Usage 207 132 36% 36% 

Site Generation 0 0 0% 

Net Energy Use 207 132 36% 36% 

Source Energy Savings 

Est Annual Source Energy 

Summary 

The homes that Ideal builds show that energy efficiency can be integrated into a production 

setting without undue complexity, nor breaking the budget. It has taken some time for them to 

implement each next change in their production setting, but their efforts to reach for the next 

highest level of efficiency have paid off. Ideal continues to search for ways to further improve 

their energy savings, investigating the use of ground-source heat pumps, desuperheaters, tankless 

water heaters, solar hot water, and photovoltaic panels, but that is for a future development and 

case study. 

156 
Development: The Legends at Mansfield 

Builder: Tindall Homes 

Location: Columbus, New Jersey 

With a background in science and 5 years of building 

experience under his belt, Mark Bergman founded 

Tindall Homes in 1986. Over the past 20 years, the 

company’s mission has been to build superior quality 

homes that offer exceptional long-term value – homes 

with greater durability and energy efficiency. Tindall 

builds 20-25 semi-custom homes per year, which 

meet ENERGY STAR building standards and range 

in size from 3,800 to 6,000 ft2 (Figures 63 and 64) 

When developing the Legends at Mansfield 

community, Tindall worked with IBACOS to achieve 

at least 30% energy-savings levels according to the 

Building America Benchmark. 

Figure 63. Rendering of Tindall’s 

Morgan home from Legends at 

Mansfield 

Figure 64. Main floor plan for a Tindall Morgan home from Legends at Mansfield 

157 
Measuring Up 

During the design phase, IBACOS and Tindall explored several options to realize 30% energy 

savings, including the use of solar electric systems and improvements to heating, cooling, 

ventilation, duct work, and the building shell. Rather than selecting a few key areas to focus on, 

Tindall chose to implement most of the design recommendations. 

Consequently, an analysis of energy use in comparison to the Benchmark for New Jersey shows 

that Tindall’s Legends at Mansfield homes were expected to exceed the 30% Benchmark, 

consuming 43.2% less energy than comparable homes. The addition of tankless water heaters, 

which could be eliminated from the design to remain within the 30% savings range, enabled 

Tindall to reach the next energy-efficiency level. After adding solar photovoltaic systems to the 

plans, the savings estimate increased to 48.4%. 

Increased Airtightness 

Before partnering with the Building America program, Tindall installed unfaced fiberglass batt 

insulation in conventional 2x4 stud walls, with studs located 16 in. on center. By using 2x6 studs 

placed 24 in. on center for the homes in the Legends at Mansfield community, Tindall was able 

to reduce the total number of studs used and significantly decrease conductive heat loss through 

exterior walls. The 3 in. of urethane foam within walls increased the insulation to R-18 and also 

added to the buildings’ airtightness. 

Optimized Heating, Ventilation, and Air Conditioning 

Because of their size and the design of their flooring structures, Tindall’s homes are typically 

conditioned by two HVAC systems: one located in the basement to serve the first floor and the 

other based in the attic to serve the second floor. Locating the second floor HVAC system in the 

attic results in significant energy loss, as the system is exposed to ambient conditions. 

For their Building America project, IBACOS and Tindall elected to use open-web floor trusses 

for the second-floor structure, allowing plumbing and duct work to run through conditioned 

space and enabling both HVAC systems to be placed in the basement. With this approach, 

Tindall reduced end use of heating energy in its Legends at Mansfield properties by 53% and the 

use of cooling energy by 45%, both in comparison to the BA Benchmark. 

Tindall also replaced its standard ventilation system with a heat-recovery ventilator, which was 

connected to the return plenum of both furnaces. This upgrade provided a means to bring fresh 

air in, capturing much of the heat contained in outgoing air before exhausting it. At the same 

time, better ventilation has resulted in improved air quality and enhanced occupant comfort. 

In addition, IBACOS’s recommendations allowed Tindall Homes to decrease the size of both 

heating and cooling equipment. Smaller equipment reduces the cost to the builder by $800 per 

home and contributes significantly to energy savings. 

Moisture Resistance 

To keep moisture from penetrating its homes from the ground up, Tindall replaced its standard 

foundation with pre-insulated, pre-cast concrete walls. The higher cement content and other 

additives within these walls provide a much greater level of moisture resistance without 

158 
requiring an additional barrier. The design of the wall system provides for a continuous layer of 

insulation on the foundation wall, and because it is a pre-cast system, the foundation can be 

installed in 1 to 2 days. 

Impact of Solar PV Systems 

When Tindall Homes began its Building America project, photovoltaic systems were a hot 

option for improving residential energy efficiency in New Jersey. At the time, builders were 

reimbursed for two-thirds of the investment under the state’s rebate program. For Tindall, this 

program provided more than $13,000 in savings on a $20,000 system. The builder analyzed the 

cost of the system versus the benefits it would provide and then decided to offer photovoltaics as 

a standard feature on all 39 homes in Mansfield Park. 

As the project progressed, however, state funding steadily declined, and program implementation 

became much stricter. The builder ended up installing solar systems on only 14 homes, because 

they did not receive the rebate level they had expected. While solar had the potential to generate 

another 51⁄2% in energy savings, it was no longer a cost-effective option. 

Table 31 summarizes estimated source energy savings from heating and cooling systems, other 

improvements Tindall implemented, and photovoltaics. Table 32 provides a snapshot of all of the 

energy related features of the houses in the community. 

159 
Table 31. Summary of Estimated Source Energy Savings 

Annual Source Energy Estimated Source Energy Savings 

Benchmark 

Tindall 

Standard 

Project 

House Percent of End-Use Percent of T

End Use (MBtu/yr) (MBtu/yr) (MBtu/yr) vs. Benchmark vs. Standard vs. Benchmark Space Heating 401 227 187 53% 17% 54% Space Cooling 74 47 40 45% 14% 7% DHW 27 20 12 55% 41% -1% Lighting 44 45 14 68% 69% 3% Appliances 28 28 28 0% 0% 0% Misc. Plug 104 104 104 0% 0% 0% Subtotal 678 472 387 43% 18% 43% PV Generation 0 0 -37 5% Total 678 472 350 48% 26% 48% 

160 
Table 32. Snapshot of Energy Features 

Foundation Insulation 

Wall Construction and Insulation 

Ceiling/Roof Construction and Insulation 

Windows 

Air Sealing 

Blower Door Test 

Ducts 

Duct Losses 

Ventilation 

Heating Equipment 

Cooling Equipment 

Hot Water System 

Solar PV System 

Lighting 

Appliances 

Exterior R-12.5 polystyrene insulation board 

2x6 wood frame, 24 in. oc, 3-in. spray urethane 

(R-18) 

Wood trusses 24 in. OC, 

Attic (flat) – R-30 fiberglass batts, 

R-19 blown cellulose (4 1⁄2 in.) 

Attic (cathedral) – R-30 fiberglass batts 

Garage ceiling – 2-in. spray urethane 

(R-12), R-30 fiberglass batts 

Low-E, gas-filled; U = 0.36; SHGC = 0.33 

Housewrap w/ joints taped, sill sealer, 

caulk/foam at interior of sill plates, foam around 

rough openings of windows and doors, 

draftstopping behind showers/tubs and 

fireplaces, at kneewalls, and chase “lids,” 

penetrations in top plates and draftstopping 

airsealed 

3.2 ACH50 

100% conditioned space 

6% total at 25 Pascals 

Heat-recovery ventilator to return plenum of 

both furnaces 

Two natural-gas 92.1% efficiency furnaces 

Two condensing units, first floor 3-Ton / 14­

SEER, second floor 2.5 Ton / 13-SEER 

Two tankless water heaters, energy factor 0.85 

2.64-kW grid-connected photovoltaic system 

≈ 95% linear or compact fluorescent, remainder 

incandescent 

Not provided by the builder 

161 
Builder Innovation, Challenges, and Lessons Learned 

Tindall Homes has invested between $16,000 and $18,000 more in first costs for its Building 

America homes in comparison to standard specifications (Table 33 shows a breakdown). Mark 

Bergman believes the investment was well worth it. 

“We all want to make money, but at some point, as a society, we have to evaluate what we are 

doing,” asserted Bergman. “Over their lifetimes, our homes will save more in energy costs than 

the cost of the energy efficient upgrades, especially when you consider energy prices will likely 

rise over time, not decrease. If all builders built to save 50% on energy use, we could make a big 

difference.” 

During the modeling process, IBACOS estimated the energy efficiency of the Legends at 

Mansfield community homes, and the HERS rating came in between 90 and 91. On average, the 

homeowners are saving about $1,500 a year in utility bills, and, assuming these homes will last 

for 100 years, they should save approximately 10 times the incremental cost of the upgrades. 

“It’s also important to recognize that many of the things that are making our homes more energy 

efficient will also make them last longer,” said Bergman. “By implementing Building America 

recommendations, our homes are more weather resistant, keeping out humidity and dampness 

problems.” 

For his next major project, Bergman will leverage his Building America experience to bring 

energy efficiency to more affordable housing. He will begin development of a 1,500-unit, mixed 

housing community within the next 2 years. It will be located across the river from Philadelphia 

and will incorporate solar-electric systems and water-conservation practices in addition to 

improved building shells and advanced HVAC strategies. 

162 
Table 33. Cost of Tindall Home Compared to Standard Building Practices in New J

Building Envelope Standard Specifications Building America Project House / 

Community Specs 

Insulation Ceiling (main) R-30 Unfaced fiberglass batts Garage Ceiling R-19 unfaced fiberglass batts Above-Grade Walls 2x4 with R-3 rigid sheathing on exterior 

and R-13 fiberglass batts 

Basement Walls R-13 foil faced fiberglass batts Windows Low-E, vinyl, argon filled, U = 0.35, 

SHGC = 0.30 

Infiltration Draftstopping Lack of draftstopping behind baths/ 

showers and fireplaces. 

Airsealing Housewrap with joints taped, sill sealer, 

caulk/foam at interior of sill plates, foam around rough openings of windows and doors, penetrations in top plates. 

R-30 kraft-faced (down) fiberglass batts + R19 blown cellulose 

2-in. urethane foam (R-12) + R-30 kraft-faced 

(down) fiberglass batts 

2x6 @ 24 in. oc w/ 3 in. urethane foam (R-18) 

Precast foundation with integral R-12.5 

insulation board 

Low-E, vinyl,, U=0.36, SHGC=0.33. Draftstopping sheathing behind tubs, 

showers, and fireplaces, at chase “lids” and the attic side of attic kneewalls. 

Same as standard practice with draftstopping 

airsealed 

+ + 

+ 

+ + 

+ 

+ 

+ 

163 
Table 33 (continued). Cost of Tindall Home Compared to Standard Practice in New 

MECHANICAL SYSTEMS 

STANDARD SPECIFICATIONS BUILDING AMERICA PROJECT 

HOUSE/ COMMUNITY SPECS 

HVAC Heating 2-92.1% efficient gas furnaces. Both @ 75,000 

Btu/h input capacity. One furnace was located in vented attic space. 

Cooling Condensing units (2) are 14 SEER (nominal) 

with a 3-ton or 3.5-ton capacity 

Ducts Sheet metal or flex duct used for all ductwork. 

R-6 insulated flex duct used in unconditioned attic. 

Ventilation Mechanical ventilator is units located in the 

basement and attic. The unit mixes outdoor air drawn by the furnace fan with indoor air before the air reaches the return air plenum. 

Structural TGI floor joists Integration 

Water Heating A power-vented 75-gallon gas hot water heater 

with 76,000 Btu/h input and energy factor of 0.59 

2-92.1% efficient gas furnaces in conditioned basements. First floor 75,000 Btu/h input Second floor 50,000 Btu/h input 1-13 SEER 2.5 ton unit 1-14 SEER 3 ton unit Sheet metal or flex duct used for all ductwork. All ductwork in conditioned space. Closer attention paid to air-sealing ductwork with mastic. 6% total duct leakage. Heat-recovery ventilator. 

Open-web floor trusses 

Two tankless water heaters with 15,000­180,000 Btu/h input and energy factor of 0.81 

164 
Table 33 (continued). Cost of Tindall Home Compared to Standard Practice in New 

LIGHTING STANDARD SPECIFICATIONS BUILDING AMERICA PROJECT HOUSE/ 

COMMUNITY SPECS 

% Fluorescent /  % Incandescent 

100% Incandescent 95% Fluorescent (strip and compact) / 5% 

incandescent TOTAL COST DIFFERENCE without PV Plus cost of 2.64-kW grid-connected photovoltaic system TOTAL COST DIFFERENCE with PV 

165 
Table 34 summarizes the incremental costs to the builder compared to their standard practice. 

While Tindall has invested approximately $16,290 in first costs over their standard practice, the 

builder believes that the added cost is definitely worthwhile, in terms of energy efficiency, 

environmental impact, and customer satisfaction. Table 34 summarizes the cash-flow analysis 

for the buyer. Amortized costs are based on a 30-year mortgage at 7% interest. While the 

additional cost of the building practices to achieve the 43% energy savings costs the buyer 

approximately $1,296 annually, they are saving $1543 annually in energy costs. This translates 

to a net positive cash flow for the homeowner of $247 per year. 

Table 34. Tindall Legends at Mansfield Cash Flows 

Total Cost of Energy Efficient Upgrades $16,290 

Annual Amortized Costs $ 1,296 

Annual Energy Savings $ 1,543 

Net Savings $ 247 

166 
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 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 

167 
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. 

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 Solar Heat Gain Coefficient [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. Orienting homes with longer sides and larger glazing areas facing north and 

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 

168 
• 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 Mixed-Humid climates, having more glazing 

face south with adequate shading can minimize cooling and heating loads significantly; 

however, 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 

thermal conductivity 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 can be 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.40 

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 

40 Sustainable Building Industries Council. Passive Solar Design Strategies: Guidelines for Home Building. 

Sustainable Building Industries Council Website. www.psic.org 

169 
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 summer while allowing for heat gain during the winter. Shading the west glass can also 

minimize the unwanted heat gains. A wide range of shading options is available, including the 

following: 

• 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 

effect. 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 while 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. 

170 
• 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 affects daylighting; consider both simultaneously. For example, a light shelf 

bounces natural light deeply into a room through high windows while shading lower 

windows. 

• 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 living 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. 

171 
Appendix B: Detailed BEopt Analysis Assumptions 

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.1. Utility and Onsite Power Inputs 

Group Input Variable Value Units 

Economics Electricity Source/Site Ratio 3.16 

 Electricity Cost 0.0632 $/kWh

 Natural Gas Cost 1.023 $/therm

 Discount Rate 0.05 

 Mortgage Interest Rate 0.08 

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 

7.5 (unless noted 

 Installed Cost otherwise) $/rated W 

Derate Factor Determined by location % 

Daily Incident Solar Determined by location kWh/m2 

Average System Efficiency Determined by location % 

172 
Table B.2. BEopt Cost Assumptions 

Category/Option Unit Cost 

Basement Insulation ($/ft) 

Uninsulated $0.00 

4-ft R-5 Exterior $0.42 

4-ft R-10 Exterior $0.77 

8-ft R-10 Exterior $0.77 

8-ft R-15 Exterior $1.12 

8-ft R-20 Exterior $1.23 

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 

173 
Table B.2 (continued). BEopt Cost Assumptions 

Category/Option Unit Cost 

Thermal Mass ($/ft

2

) 

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 

174 
Table B.2 (continued). BEopt Cost Assumptions 

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 ft

3

, 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 ft

3

, 

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 

175 
Table B.2 (continued). BEopt Cost Assumptions 

Category/Option Unit Cost 

Efficiency Cost ($) = 

Air Conditioner SEER value 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 

Capacity Cost ($) = 

Air Conditioner Capacity (tons) 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 

176 
Table B.2 (continued). BEopt Cost Assumptions 

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 ($/ft

2

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 

177 
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 and 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. 

• HVAC 

o Load-calculation, Ventilation, and Equipment-selection Specialist 

o Duct-Design Specialist 

o Air-Distribution System-Installation Specialist 

o Equipment-Installation and Start-up Specialist 

– Fossil fuel and electric heating 

– Refrigeration 

– AC / Heat Pump 

o Airflow-Balancing Specialist 

• Carpentry 

o Framing Specialist 

• Thermal envelope 

o Insulation Specialist 

o Air-sealing Specialist 

• Above-grade Moisture Management 

o Window- and Door-Installation Specialist 

o Wall-Drainage-Plane Specialist 

o Roof-Drainage and Flashing Specialist 

• Below-grade Moisture Management 

o Below-Grade Moisture-Management Specialist 

• Designers 

o Architect / Residential Designer 

o Engineer 

178 
Within each of the specializations is a more detailed description of the probable roles and 

competencies required. 

HVAC 

• Load-calculation, Ventilation, and Equipment-selection Specialist 

o Proficiency in ACCA Manual J method for load calculation and how to account for 

higher performance when calculating heating and cooling loads 

o 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 

o Surface-area competencies and understanding of thermal-envelope assemblies 

(i.e., framing factors, window properties, etc.) 

o Understands the types of ventilation systems and their interaction with the heating and 

cooling equipment 

o Understands dedicated humidity-control options and how to integrate with spaceconditioning systems 

o Understands the internal gains and latent loads associated with people and ventilation 

o Understands the impact of climate, shading, and other environmental impacts on the 

building 

• Duct-Design Specialist 

o Understands the impact of duct friction with respect to airflows (equivalent length 

methods – ACCA Manual D) 

o Familiarity with structural systems and limitations regarding using running-duct systems 

within structural systems (floor framing systems, walls, etc.) 

o Air-distribution options in higher performance homes (high sidewall, central return, etc.) 

o 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 

179 
• 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 

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.) 

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) 

180 
o Crawl-space vapor-barrier installation 

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 

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 

181 
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 

Designers 

• Architect / Residential Designer 

• Engineer 

182 
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 IBA

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. 

Perof cBenthreexcindu

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. 

One for perof tdeswarSento aper

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. 

Perare initi

183 
Table D.1 (continued). Leadership 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

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. 

Spaeuip

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

1.4 Living the Mission 1.5 Public Responsibility 

Employees may have different priorities but there is a general understanding of what the company is trying to accomplish. Some people at the company are personally involved in activities that benefit the community, the public, or the housing industry. 

Most employees know key elements of the company mission, values, and vision for the future and could explain how it relates to their job. When asked, the company supports activities to benefit the community, the public, or the housing industry. 

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set. 

184 
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 IBAC

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. 

Level supplstatissampplace perfometri

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. 

Perfomeasbased desigconstappro

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. 

Most are inperfostandproceundethese play wcontequalit

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. 

Track functieffectconstimpro

2.1 Company-wide Success Drivers and Performance Measures. 2.2 Strategic Plans 2.3 Plan Deployment 2.4 Monitoring Progress to Plan 

Measures of company performance are limited to sales and profit. Company improvement strategy is to increase sales and reduce costs, but specific action plans are not in place. The senior managers who make the strategic plans also carry out the improvement initiatives. Employees are involved on an as-needed basis. Progress is monitored on an as-needed basis. 

In addition to level 1, customer satisfaction is important, but performance data is not tracked. The company's competitive business strategy includes improving customer satisfaction and products that enhance homeowner value. Senior managers develop the strategic plan with some employee input. The plan is used to set departmental objectives. Quarterly review meetings monitor improvement progress. 

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set. 

185 
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

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

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. 

Psaindeap

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

3.1a Market Research 3.1b Product Design Processes 3.2 Customer Satisfaction Drivers 

Market requirements are learned mainly from customer requests. A company expert or consultants create new home designs. Avoiding homeowner disappointment with the constructed product is the main customer satisfaction priority. 

In addition to level 1, market trends are learned from tours of other builders' products and builder magazines. In addition to level 1, select employees provide some input into the design process. Completing the home on time with a short punch list at final inspection is the company’s main focus for satisfying customers. 

186 
Table D.3 (continued). Customer Satisfaction 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

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

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

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. 

Pinr

3.3 Customer Relationship Management 3.4a Customer Satisfaction Measurement 3.4b Sharing of Customer Satisfaction Feedback 

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. Customer satisfaction feedback data consists of final inspection punch lists and warranty callbacks. Customer complaints are shared with the persons responsible. 

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. Customer satisfaction is measured occasionally by surveys or by asking customers. Some questions ask customers to rate employee performance. Customer letters and surveys are routinely circulated among employees. 

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 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. 

187 
Table D.3 (continued). Customer Satisfaction 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

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

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. 

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set. 

188 
Table D.4. Performance Management 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

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

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. 

Tinimpa5 

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 company-wide key success measures. Results are shared with all employees. 

Pain 

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. 

Qmwim

4.1a Creating HighPerformance Work Processes 4.1b Bench-Marking Business Processes 4.2 Performance Management 4.3 Process Improvement 

Meeting minimum performance expectations is an important priority for most employees. Information on how other builders do things is obtained mostly from publications and seminars. Performance is managed by monitoring the productivity of individual employees. 

Problems are handled as they occur to avoid customer complaints. 

Most employees have well-defined responsibilities. Finding ways to reduce costs is the main focus of work improvement activities. Occasional visits to other builders are made to get some good ideas. In addition to level 1, conformance to department budgets is used to manage financial performance. 

Changes to company processes are made occasionally to prevent recurring problems. Some employees are involved in improvement projects. 

189 
Table D.4 (continued). Performance Management 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

Most company work 

processes show measured quality improvements. 

Most company work processes show measured quality improvements and excellent quality results. 

Pam

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

4.4 Improvement Results 4.5 Financial Improvement Results 

Some company work processes seem to be improving, but there are no measures of progress. Some improvements have resulted in cost reductions. 

Some company work processes show measured quality improvements. Substantial cost reductions have been made but have not yet helped improve home sales. 

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set. 

190 
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 IB

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. 

Rpamcs

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. 

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. 

Orepstr

Some natural work groups are formed into operating teams with shared responsibilities. 

Most employees are part of an operating team with a well-understood 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. 

Pimbst

5.1a Employee Satisfaction 5.1b Jobsite Safety 5.1c Job Responsibilities 5.1d Teamwork 

The company shows a general concern for employee well-being and morale. There are occasional safety-related training activities. Employees learn job responsibilities from on-the-job experience. Individual effort is the main way things get done. 

191 
Table D.5 (continued). Human Resources 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 IB

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 long-range company vision. 

Tpsa

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 buildingperformance standards 

Employee performance evaluation criteria are based on fulfillment of personal development plans and key elements of the company mission, vision, and values. 

BsK

5.2 Workforce Development 5.3 Employee Evaluation and Compensation Systems 

Skills are learned on the job. Most employees receive an annual performance review. 

Work-related training is delivered as needed when time and budget allows. Annual employee performance reviews have well-defined evaluation criteria. Bonuses and recognition reward individual efforts. 

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set. 

192 
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

193
Table D.6 (continued). Quality Construction Processes 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 IB

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

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

6.4 Warranty Service 6.5 Product and Service Quality Results 

Service callbacks are handled but not tracked. Product and service quality seems to be improving, but there are no measures of progress. 

Systems are in place to track warranty complaints and their completion. Problems found at final inspection are decreasing. There are fewer callbacks. 

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set. 

194 
Table D.7. Supplier Partnerships 

Partnering approaches are essential for high performance relationships with trade contractors and product manufacturers. 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 IB

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

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

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

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

7.1 Trade Contractor and Supplier Relationships 7.2 Trade Development 

7.3 Trade Contractor Performance Management 7.4 Trade Contractor and Supplier Results 

Difficult quality problems are usually solved by changing contractors or suppliers. There are no formal initiatives to develop the capabilities of trade contractors. 

Trade performance is evaluated when problems arise or when contracts are renewed. Trade contractor quality seems to be improving, but there are no measures of progress. 

A systematic process is in place for the selection of trade contractors. Trades and suppliers participate in solving problems. Improving trades is focused on solving problems. 

Trade performance data consists of inspection punch lists and callbacks, but trend data is not tracked. Some trade contractors show 

measured quality 

improvements. 

195 
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 ? 

196 
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 ? 

197 
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? 

198 
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? 

199 
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? 

200 
Appendix E. High-Performance Scopes of Work

Trade Contractor Standards and Description of Work Performance 

The Company’s Terms and Conditions are by reference a part of all Scope of Work requirements. 

The Company’s Construction Documents including Construction Drawings and Specifications, 

these “Trade Contractor Standards and Description of Work Performance” and the “Trade 

Contractor Requirements and Checklists” are included by reference as a description of the Work 

to be performed by The Trade Contractor and are by reference a part of the agreement between 

The Company and The Trade Contractor. 

Construction Requirements 

Generally speaking, the work of Trade Contractor and their employees is expected to be 

performed in a good and workmanlike manner. Workmanlike quality is defined as workmanship 

which meets or exceeds those criteria indicated in applicable building codes, The Company’s 

specific performance requirements, NAHB’s Residential Construction Performance Guidelines, 

and manufacturer specifications, using materials and installation methods identified in the 

construction documents (plans and specifications) and the Trade Contractor Requirements and 

Checklists. The quality of The Trade Contractor’s installation is expected to support the quality 

of the builder’s design and specified materials. 

Code Requirements 

All jobs shall conform to those standards stipulated in the building code, mechanical code, 

plumbing code, and electrical code applicable in the local jurisdiction. “Code” means the 

minimum standard that will achieve an occupancy permit. It does not necessarily mean “quality” 

or “high performance.” 

If any high performance requirements pertaining to the Trade Contractor’s Work are in conflict 

with either the local building code or local code official interpretation of the local building code, 

it is the responsibility of the Trade Contractor to notify The Company of any conflict as soon as 

the Trade Contractor becomes aware of any such conflict. 

High-Performance Requirements 

High Performance Requirements address the major damage functions that affect materials and 

buildings: heat, water, radiation (ultraviolet) and biological organisms (which frequently require 

liquid water). Reducing the risk of damage by these forces is accomplished principally by 

controlling the following flows across the building enclosure: energy (thermal and ultraviolet 

radiation), air (heat and moisture), water (liquid, capillary and vapor) and insects and other pests. 

201 
The High Performance Requirements for each Trade Contractor’s Work make explicit the 

general premise that quality and high performance are linked—one cannot be achieved without 

the other. While a worker could successfully satisfy the requirements in the scopes without 

understanding the objective or the rational, an informed worker is more likely to satisfy the intent 

of the requirements and is definitely more likely to devise alternative solutions that may be as or 

more effective, as easy or easier to accomplish, and as or less expensive. 

Trade Contractor-specific High Performance Requirements are contained in the Introduction of 

the Trade Contractor Requirements and Checklists for each Trade Contractor. 

General Requirements 

The general requirements refer to the specific manufacturer’s instructions or requirements or a 

specific trade organization’s requirements for performance or installation practices. The Trade 

Contractor shall notify The Company (Superintendent) if a discrepancy is identified between the 

manufacturer’s requirements and The Company’s specific requirements. 

All installations are the responsibility of The Trade Contractor. It is also the responsibility of 

The Trade Contractor to: 

1. Ensure that each of their installation employees has read and understands the Trade 

Contractor Requirements and Checklists.

2. Designate a Trade Contractor supervisory representative to complete and sign the Pre-Work 

Inspection and the Post-Work Inspection Checklists contained in Trade Contractor 

Requirements and Checklists. 

Completed Pre-Work Inspection and Post-Work Inspection Checklists must be and kept on file at 

The Trade Contractor’s office. 

Interaction with Other Trades 

Construction is a process that involves sequential work performed by a variety of subcontractors. 

The Trade Contractor must understand that his Work does not occur in isolation; rather it must 

integrate with Work that precedes and follows his Work. Each contractor must therefore preserve 

the integrity of the prior Work performed by other contractors. The Trade Contractor 

understands the importance of the continuity of drainage planes, air barriers, and thermal barriers 

and will train their employees to protect these systems or repair them if they are compromised 

during their course of their Work. The Trade Contractor Requirements and Checklists expresses 

trade interaction concerns and items in the Introduction as well as throughout the Requirements, 

associated Details, and Checklists, but particularly in the Pre-Work Inspection Checklist. The 

Pre-Work Inspection Checklist in Trade Contractor Requirements and Checklists establishes the 

status of these systems before The Trade Contractor begins work while the Post-Work 

Inspection Check List in Trade Contractor Requirements and Checklists verifies their status at 

the conclusion of The Trade Contractor’s work. 

202 
General Comments 

1. The Company considers our Trade Contractors to be experts at producing a high-quality job. 

But everyone on our construction team—staff, Trade Contractors, and suppliers—recognizes 

the importance of providing quality in both the product and service areas while on our 

jobsites and in the homes of our purchasers. 

2. Since we work as a team, poor quality or service from any of us reflects unfavorably on all of 

us. An exceptional level of product quality and highly effective service can help us all to 

increase our business and grow. 

3. The Company’s definition of quality construction also requires that every job be completed 

correctly the first time. When this does not occur, it costs both of us additional money, imposes 

on the purchaser, and hurts our reputations as quality builders. That is why, in situations where 

construction was not completed in a quality manner, prompt corrective action is required to 

remedy specific deficiencies. 

4. In the following information the term ‘Site Superintendent’ refers to any Company representative 

with authority to perform the specified task. The term Trade Contractor means The Trade 

Contractor’s organization or any representative who is assigned the authority to perform the 

specified task. 

Detailed Job Requirements 

1. A new set of plans is required for each house. Plans are subject to changes and modifications. 

It is the responsibility of The Trade Contractor to have the new plans before beginning work. 

Plans should be picked up at the job trailer from the Site Superintendent, or provided to the 

Trade Contractor’s installation crews by the Trade Contractor. Any errors that occur from 

using an incorrect set of plans will be corrected by The Trade Contractor at no cost to The 

Company. 

2. Purchase orders shall be transmitted to The Trade Contractor from The Company’s office 

and shall be provided in ample time for The Trade Contractor to have the correct materials 

on hand prior to starting the Work. 

3. Specific installation instructions, including associated Details, are supplied in Trade 

Contractor Requirements and Checklists. 

4. Performance testing, when applicable (as detailed below), will be one method of testing the 

success of the installation. 

5. Any items found during the final inspection that need correction shall be corrected before 

payment will be made. 

203 
Performance Testing 

1. When an appropriate test method exists to evaluate the performance of the installation, it will 

be detailed in this section. Testing protocols that may apply include 100% testing (every 

installation), random percentage (e.g. 1 in 7) or the reserved right to test any installation as 

determined by The Company or the Site Superintendent. Test protocols, and the definition of 

successful performance or the threshold for successful performance are detailed in the Trade 

Contractor Requirements and Checklists . 

2. The definition of successful performance or the threshold for successful performance will 

also be detailed. 

3. The Trade Contractor will be responsible for correcting the installation so that performance 

meets the stated threshold. The cost of corrective action is the responsibility of The Trade 

Contractor. 

204 
Inspection Checklist 

1. The post-installation inspection checklist documents The Trade Contractor’s compliance 

with the performance requirements that are explicitly detailed in Trade Contractor 

Requirements and Checklists. The Post-Inspection Checklist is contained in Trade 

Contractor Requirements and Checklists. 

2. Inspection checklists are provided to document successful completion of the installation as 

included in Trade Contractor Requirements and Checklists. If the installation fails to meet 

the requirements specified in this Scope of Work or conform to the Finished Detail then The 

Trade Contractor must correct any deficiency found during any inspection at no cost to The 

Company. If the deficiency is discovered prior to payment, the deficiency must be 

successfully corrected before payment will be made. 

3. Performance test results will be reported on the Post-Work Inspection Checklist. Note that 

there are times when the specific performance test cannot be performed until well AFTER 

the completion of the work, after completion of the checklist and even after the deficiency 

can be readily remedied by the responsible Trade Contractor. When this occurs, the Trade 

Contractor will take reasonable and practical measures to fix the performance failure, and 

develop a corrective action plan with the builder to identify the cause of the performance 

failure and how the Trade Contractor will meet the performance requirement in the future. It 

is conceivable that the deficiency for which the Trade Contractor is responsible will be 

worked out within the broader financial agreements and exchange between The Company and 

the Trade Contractor, rather than on the level of one particular home. 

4. The Trade Contractor and the Site Superintendent must sign-off on all deficiencies attesting 

that the job is 100-percent complete and is correct per the job requirements found in this 

Scope of Work. 

I ______________________________________ agent for ______________________________ 

have read and fully understand the above Scope of Work and I hereby agree to perform all work 

in accordance with the above. 

Date: ___________ ______________________________________________ 

 Signed: Trade Contractor (or agent) 

Date: ___________ ______________________________________________ 

 For The Company 

205 
Mixed-Humid Climate Foundation Requirements and Checklists 

Foundation Requirements 

1. Introduction – High Performance Foundation 

[NOTE: for the purposes of this scope of work, it is assumed that the foundation 

contractor is responsible for the foundation, system which includes structural footings, 

piers, slabs, and walls, the water management system including perimeter drainage and 

damproofing / waterproofing. To the extent that these activities are separately contracted 

by The Company, this Scope of Work should be split to focus on those work areas each 

Trade Contractor will be responsible for.] 

High Performance is defined as superior energy efficiency, safety, comfort, and durability. 

Managing the flows of moisture and air with the same thoroughness as energy protects against 

the major damage functions a home faces— heat, water, radiation (ultraviolet) and biological 

organisms (frequently requiring liquid water). 

The work of the Foundation Trade Contractor contributes to high performance in the following 

ways: 

• Water management – 

o Installation of a capillary break between footings and foundation walls 

o Installation of a capillary break on the below-grade portions of exterior 

foundation walls 

o Installation of a capillary break between the soil and the concrete slab 

o Installation of a perimeter drain system along footings for basements and crawl 

spaces where the floor is below the exterior grade 

o Installation of a capillary break on both the above grade and below grade 

perimeter of slab on grade foundations 

• Integrity and Continuity of the Thermal Barrier – 

o Installation of foundation insulation in a continuous manner 

o Installation of sub-slab insulation in a continuous manner 

• Integrity and Continuity of the Air Barrier – 

o Installation of the concrete and foundation walls so that they can function as an air 

barrier. This is accomplished by providing control joints and expansion joints in 

the proper locations. These known areas of actual or potential cracks in the air 

barrier can then be properly sealed. 

206 
o Installation of continuously sealed vapor barrier ground cover on the floor of a 

crawl space also provides an air barrier between the soil and air within the crawl 

space. 

• Vapor management – 

o Installation of the polyethylene vapor barrier under concrete slab 

o Installation of the polyethylene vapor barrier/ground cover on the floor of a crawl 

space 

o Installation of dampproofing on the below ground sections of foundation walls 

Construction is a process that involves sequential work performed by a variety of subcontractors. 

The Foundation Trade Contractor’s work is generally followed by The Framing Contractor, The 

Roofing Contractor, The Drainage Plane Contractor, The Window Trade Contractor, The 

Insulating Contractor and later by The HVAC Contractor with these high performance 

implications: 

• Air sealing must be accomplished between the top of foundation walls and the sill plate. 

Levelness and uniformity of the top of the foundation walls facilitate air sealing. 

• Air sealing must be accomplished between rough openings for windows and doors. 

Dimensional accuracy and uniformity of these openings facilitate air sealing between the 

foundation wall and windows and doors. 

Performance testing is often a key step along the path to high performance. 

• Water testing of the perimeter drainage system can determine the ability of the perimeter 

drainage system to transport water. 

• Successful performance is the free flow of water from any section of the perimeter 

drainage system to the opening to daylight or the sump pit. 

The Foundation Trade Contractor will be responsible for correcting deficiencies in installation 

so that performance meets the requirements of The Company and high performance in these 

Scopes. The cost of corrective action is the responsibility of The Foundation Trade Contractor. 

For more comprehensive information on the relationship between foundation installation and 

high performance homes, see the following resources: 

• Builder’s Guide to Mixed-Humid Climates (August 2005) specifically Chapters 2 and 7. 

• Building America Best Practices Series Volume 4 

(www.nrel.gov/docs/fy05osti/38448.pdf) 

• Designs That Work – Mixed-Humid Climates 

(www.buildingscience.com/designsthatwork/default.htm) 

207 
Detailed Installation Checklist 

Pre-Work Inspection: completed and signed by Site Superintendent and The Foundation 

Trade Contractor 

Foundations – Types – Check all that apply to this building 

 Slab at Grade - Slab 

Basement – BSMT 

 Crawl Space – interior grade below exterior grade – CS-BG

 Crawl Space – interior grade above exterior grade – CS-AG 

Detailed Installation Checklist

 1. Install capillary break on top surface of footing using specified material. 

2. Install a minimum of 4 inches of crushed stone – 0.75 inch diameter, no fines. – under 

slabs and under ground covers in crawl spaces. 

3. Install sub slab soil gas ventilation pipe – 4 inch perforated pipe, minimum total length of 6 

feet, with central T-fitting that connects to the vertical solid pipe that will continue 

through the roof. Cap the short section of vertical pipe (minimum 6 inches above top of 

finished slab) to prevent concrete entering the pipe. 

4. Install sub slab rigid insulation – extruded polystyrene, expanded polystyrene or high 

density mineral wool – on the crushed stone as specified in plans. 

5. Install 0.75 inch rigid insulation as bond break between the foundation walls and the slab 

edge. 

6. If a vapor retarder (polyethylene) is called for, it is installed on top of the rigid insulation 

in direct contact with the underside of the concrete slab. 

7. For slabs with turned down edge, place the rigid insulation against the concrete form and 

place the polyethylene in footer trench and continue up to the top of the form. The 

polyethylene is placed interior to the rigid insulation so that the polyethylene will be in 

direct contact with the concrete. See Figure 1. 

8. For slabs at grade with stem wall install rigid insulation along stem wall an under slab as 

called for in plans. 

9. Control joints have been placed at the appropriate locations in all slabs. 

10. Perimeter foundation drainage system installed along side the footings as shown in Figure 

2. 

 11 Perimeter drainage system is connected to: (per plans or instructions from The Company) 

 Daylight 

Interior drainage field and sump pit 

12. Dampproofing installed on basement and crawl space walls to height of final grade. 

13. Drainage board or free draining “backfill” installed per plans and specs. 

208 
Concrete Slab 

Protective 

Cover 

At Rigid 

Insulation 

Stone Pad

(Min 4" - No Fines)

Rigid Insulation

Polyethylene

Ground Cover

(Continue Up

Exterior Face of

Foundation)

Figure E-1. Slab at grade – polyethylene under turned down edge and rigid 

insulation along perimeter of slab foundation 

Free Draining Backfill 

Damproofing / Waterproofing 

(As Required By Site Conditions) Filter Fabric 

Stone Drainage 

Backfill At Drain 

Concrete� 

Foundation Wall 

Capillary Break 

Concrete 

Footing 

Perimeter 

Footing Drain 

Relief 

Connector 

Figure E-2. Perimeter Drainage System along Footer 

Refer to additional foundation details contained in the Builder’s Guide to Mixed-Humid 

Climates (August 2005), specifically Chapter 7 and Chapter 10. 

209 
Pre-Work Inspection Checklist 

To be completed before the Trade Contractor starts work on the jobsite: 

1. Construction is at the appropriate stage and conditions are acceptable for The Foundation 

Contractor to begin work. 

2. Appropriate materials and equipment are onsite for work to be performed by The

Foundation Trade Contractor.

 4. The Foundation Trade Contractor has current plans. Record date of plans: [___/___/___]

 5. The Foundation Trade Contractor has current Company specifications for foundation 

installations. 

6. The Foundation Trade Contractor has reviewed and accepts all high performance items 

that appear in the Detailed Installation Checklist 

Company Rep’s Initials ________ 

Trade Contractor’s Initials ________ 

210 
Post-Work Inspection Checklist 

To be completed before Trade Contractor leaves jobsite: 

1. The perimeter drainage system is installed. 

2. The perimeter drainage system terminates to daylight or to the sump pit. 

3. Dampproofing is present to final grade on crawl space and basement walls. 

4. All site details match the Foundation Details. 

5. No unapproved material substitutions have been made from The Company specs. 

6. Crushed stone is to the proper depth is present on crawl space floors. 

7. The soil gas ventilation pipe is present at the proper location, and marked so as not to be 

mistaken for a sewer connection. 

8. Control joints are present at the correct locations in concrete slabs. 

9. Water testing of the perimeter drainage system successfully demonstrated the ability of the 

drainage pipe to transport water daylight or to the sump pit. 

10. The Trade Contractor installer checklist is completed and signed. 

Company Rep’s Initials ________ 

Trade Contractor’s Initials ________ 

211 
Mixed-Humid Climate Framing Requirements and Checklists 

Framing Requirements 

1. Introduction: High-Performance Framing 

High Performance is defined as superior energy efficiency, safety, comfort, and durability. 

Managing the flows of moisture and air with the same thoroughness as energy protects against 

the major damage functions a home faces— heat, water, radiation (ultraviolet) and biological 

organisms (frequently requiring liquid water). 

The work of the Framing Trade Contractor contributes to high performance in the following 

ways: 

• Water management – 

o Capillary break installed between ALL bottom plates and concrete or masonry 

o Prompt installation of or enablement of prompt installation by a subsequent Trade 

Contractor of the roofing underlayment over sheathed roofs and weather-resistive 

barrier on walls 

o Installation of framing and sheathing materials not in excess of 19% moisture 

content and free of mold growth. 

o Installation of structural sheathing and insulating sheathing to prevent, to the 

greatest extent possible, water penetration into interior during construction, and if 

applicable as part of the final drainage plane strategy as determined by The 

Company. 

• Integrity and Continuity of the Thermal Barrier – 

o Five-sided enclosure (top, bottom, sides, and rear) for insulation in all framing 

cavities separating conditioned space from unconditioned space for those areas to 

receive drywall by others. In concealed areas not to receive drywall as a finish 

material, The Framing Contractor shall coordinate with The Supervisor and The 

Insulation Contractor to assure that insulation is encapsulated on all six sides (see 

the Installation Checklist for details, and the EPA Thermal Bypass Checklist, 

www.energystar.gov/ia/partners/bldrs_lenders_raters/downloads/Thermal_Bypass 

_Checklist.pdf.). 

o Efficient framing, such that two-by stock is used only where structurally 

necessary. 

• Integrity and Continuity of the Air Barrier – 

o Air seal at all bottom plates on exterior walls 

212 
o Install plywood or OSB structural sheathing with gaps as required by the 

manufacturer. Where insulated Sheathing is installed, butt panel joints tightly and 

tape joints (if applicable). 

o In concealed areas not to receive drywall as a finish material, the framing 

contractor shall coordinate with the site supervisor and insulation contractor to 

assure that insulation is installed and encapsulated on all six sides of frame wall 

cavities (see the Installation Checklist for details). 

o Installation of draft stops in areas that will not be accessible after completion of 

framing (see the Installation Checklist for details). 

• Vapor management 

o No substitutions of sheathing materials with performance properties (including 

water absorption and vapor permeability) different than the sheathing materials 

specified. 

Construction is a process that involves sequential work performed by a variety of subcontractors. 

The Framing Trade Contractor’s work is generally preceded by The Foundation Trade 

Contractor, with these high performance implications: 

• Foundation insulation – protect this material and replace as necessary when damaged as 

the result of framing work. 

• Foundation drainage system – protect this system and replace as necessary when 

damaged as the result of framing work. 

The Framing Trade Contractor’s work is generally followed by The Roofing Contractor, The 

Drainage Plane Contractor, The Window Trade Contractor, The Insulating Contractor and later 

by The HVAC Contractor with these high performance implications: 

• Flashing and/or weather-resistive barriers installed in rough openings must accommodate 

integration with window and door unit flashings, particularly at the sill and head. 

• Framing layout in high performance homes is done in coordination with HVAC layout of 

equipment and ducts—do NOT vary from the framing layout or add framing/blocking 

that could interfere with a high performance HVAC installation. 

• Framing, sheathing and airflow retarder components (this last IF installed by the Framing 

Trade Contractor) must be properly installed to permit full insulation of building cavities 

in an airtight manner. 

Performance testing is often a key step along the path to high performance. Infra-red thermal 

imaging and air leakage testing (blower door) can act as performance tests for efficient framing 

and draft stop details. These tests may be used by The Company to verify the contribution of the 

frame to the thermal and air barriers. Unfortunately these tests can generally be done only at a 

much later stage of construction when corrective action is quite costly. It is, therefore essential 

that these details be successfully executed. Successful performance is defined as the addition of 

no unnecessary framing materials in substitution of thermal insulation and the presence of draft 

stop materials in all problematic air sealing areas as shown on the framing plans and Details in 

SOW #2. 

213 
A critical component of high performance framing can be detailed framing layouts (See Figure 1 

in the Installation Checklist). Detailed framing layouts can “codify” thermal and air barrier 

continuity and integration of framing with HVAC design and installation. 

The Framing Trade Contractor will be responsible for correcting deficiencies in installation so 

that performance meets the requirements of The Company and high performance in these Scopes. 

The cost of corrective action is the responsibility of The Framing Trade Contractor. 

NOTE: The EPA ENERGY STAR program has identified 13 of the most common air leakage 

and thermal bypasses. For more information, see: 

www.energystar.gov/ia/partners/bldrs_lenders_raters/downloads/Thermal_Bypass_Checklist.pdf. 

For more comprehensive information on the relationship between framing and high performance 

homes, see the following resources: 

• Builder’s Guide to Mixed-Humid Climates (August 2005) 

• Building America Best Practices Series Volume 4 

(www.nrel.gov/docs/fy05osti/38448.pdf) 

• Designs That Work – Mixed-Humid Climates 

(www.buildingscience.com/designsthatwork/default.htm) 

2. Detailed Installation Requirements

 Pre-Work and Post –Work Inspection checklists will be completed and signed by Site 

Superintendent and The Trade Contractor 

1. Install Capillary break (closed-cell foam sill sealer or rubber membrane) underneath 

carrying beams at foundation beam pockets. 

2. Install a double layer closed-cell foam sill sealer as a capillary break and air seal 

underneath all bottom plates that rest on concrete or masonry and separate conditioned 

from unconditioned spaces, including vertical transitions at foundation steps. 

3. Install capillary break (closed-cell foam sill sealer or rubber membrane) under interior wall 

partitions on concrete slabs 

4. If a framing layout plan is provided by The Company, install all framing per the framing 

layout plan (See example in Figure 1 below). 

5. Use of structural lumber shall be limited to structural applications. This includes the 

following on walls that separate conditioned space from unconditioned space (See Figure 

2 below): 

 drywall stops at inside corners interior partition/exterior wall drywall stops 

 minimized number of cripples minimized number of studs at rough openings

 2- or 3-stud corners top plates (single)

 6. All headers are load-tuned—they are sized to the specific load they will carry. Install 

headers only of the size and material as called out on the framing plans/specifications. 

214 
 7. Install a capillary break at locations where wood based sheathing (i.e. plywood, OSB) runs 

past the framed wall and contacts concrete or masonry. The capillary break is installed 

between the sheathing and concrete or masonry.

 8. All framing cavities that separate conditioned space from unconditioned space are to be 

framed to form a five-sided (top, bottom, two sides, and rear) cavity to contain the 

insulation and prevent air from moving through air permeable insulation products (see 

Figure 3 below). The sixth side of most of these cavities will be completed with the 

installation of with the interior gypsum board, or other air impermeable finish interior. 

Those cavities that will NOT be finished with and air impermeable interior sheathing shall 

be sheathed with thin-profile sheathing, plywood, OSB, gypsum board, or other air 

impermeable sheathing products by The Framing Contractor. These areas include, but are 

not necessarily limited to: 

a. tub surrounds on exterior walls 

b. soffits terminating on exterior walls 

c. framed fireplace/entertainment center/seat enclosures on exterior walls

 d. plumbing/electrical/HVAC chases at attic or exterior walls 

 e. other architectural details that require framing on walls that will be insulated 

9. All framing cavities that separate conditioned space from unconditioned space shall be 

sheathed on both sides of the stud cavity. If they are not sheathed as part of the building 

exterior, they are sheathed with a continuous, air sealed, air impermeable material to 

accomplish the five-sided enclosure for cavity insulation containment (See Figure 4 

below). This includes but is not limited to the following areas: 

 a. attic knee walls 

b. ceiling height transition walls that abut attic space

 c. walls that abut unconditioned front entryways

 d. walls that abut future conditioned space 

10. If required by The Company, rigid insulation of the thickness specified in the 

Specifications shall be installed as exterior sheathing and shall be installed on all walls 

that separate conditioned from unconditioned space. 

IF the rigid insulation is part of a continuous air barrier, then all seams in the rigid 

insulation are taped with material as specified by The Company. 

IF the rigid insulation is part of the drainage plane, than all vertical seams are taped and 

all horizontal seams are “z”-flashed with 18-inch wide polyethylene sheathing. That is, after 

each course of rigid insulation is installed, polyethylene strips are fastened 8 to 9 inches up 

the framing from the top edge of the rigid insulation, draping down so that as the next course 

of rigid insulation is installed, the poly flashing forms a weatherlapped joint. 

11. Air seal band or rim joists by installing a continuous bead of construction adhesive 

between the mudsill or top plat and the perimeter band or rim joists, between the subfloor 

and the perimeter band or rim joists, and at all vertical butt joints in the perimeter band or 

rim joists. 

215 
 12. Exterior sheathing material matches The Company’s specifications. Alternate materials 

must be approved in writing by The Company. 

13. Install all framing and framing accessory materials per manufacturer installation 

requirements. Any deviation from the manufacturer installation requirements must be 

approved by The Company. 

NOTE: If The Company includes roofing underlayment installation in the responsibilities of The 

Framing Contractor, see the Scopes of Work documents for The Roofing Trade Contractor. 

NOTE: If The Company includes drainage plane installation in the responsibilities of The 

Framing Contractor, see the Scopes of Work documents for The Drainage Plane Contractor. 

NOTE: If The Company includes window installation in the responsibilities of The Framing 

Contractor, see the Scopes of Work documents for The Window Installation Contractor. 

216 
3. Details and Sequenced Drawings

Figure E-3. Framing layout (image courtesy of Building Science Corporation) 

217 
Insulated 

Exterior 

Wall 

Drywall 

Clip Insulated Exterior Wall 

Drywall Clip 

Interior Wall 

Drywall clip at interior corner Drywall clips at interior partition 

Exterior Wall Top Plate 

Interior Wall Top Plate 

Metal Connector Plate 

Exterior Wall Top Plate 

Metal Connector Plate 

Exterior Wall Top Plate 

Top Plate Splice 

Solid Blocking 

Methods for joining single top plates 

Figure E.4. Efficient framing details 

218 
Provide Continuos 

Closure At Interior 

Face Of Exterior 

Wall At Soffit 

Continuous Bead 

Of Sealant - Typical 

Insulated 

Exterior Wall 

Kitchen 

Cabinetry 

Draft stop behind soffit 

Section At Chase 

Seal All Penetrations 

At Ceiling Of Chase 

Provide Sealed 

Closure At Top 

Of Chase 

Provide Sealed 

Closure At Interior 

Face Of Exterior 

Wall 

Plan At Chase 

Draft stops: Upper drawing shows draft stop where chase meets 

attic and pipe continues into attic; lower drawing shows draft stopping 

where chase meets exterior wall. 

Figure E-5. Draft Stopping Details – Group 1 

219 
Provide Sealed 

Closure At Interior 

Face Of Exterior 

Wall 

Insulated Exterior 

Wall 

Figure E-6. Draft stop behind fire place insert 

Provide Continuous 

Sealed Closure At 

Interior Face Of 

Exterior Wall At 

Bathtub 

Insulated 

Exterior Wall 

Figure E-7. Draft stop behind bathtub 

220 
For additional framing details, refer the Builder’s Guide to Mixed-Humid Climates (August 

2005), specifically Chapter 11. Additional framing details can be found at 

(www.buildingscience.com/designsthatwork/default.htm) 

Pre-Work Inspection Checklist 

To be completed before the Trade Contractor starts work on the jobsite: 

1. Construction is at the appropriate stage and conditions are acceptable for The Trade

Contractor to begin work. 

2. Measured moisture content of framing lumber does not exceed 19 %. 

3. If available from The Company, HVAC equipment and duct layout and sizing have been 

reviewed for integration/compatibility with the framing plans. 

4. Appropriate materials and equipment are onsite for work to be performed by The Framing 

Trade Contractor.

 5. The Framing Trade Contractor has current plans. Sign off on date of plans: [___/___/___]

 6. The Framing Trade Contractor has current Company specifications for all framing and 

framing accessories materials. 

7. The Framing Trade Contractor has reviewed and accepts all High Performance Framing 

Requirements listed in the Introduction to Framing Requirements and Checklists. 

8. The Framing Trade Contractor has reviewed and understands/accepts the Framing 

Requirements and Checklists including the associated details; in particular, five-sided or 

six-sided containment for all framing cavities that will be insulated. 

9. The Framing Trade Contractor has reviewed and understands the HVAC duct layout and 

other mechanical system layouts, and has coordinated the framing layout with the 

Supervisor to ensure no conflicts with the work of The Company’s HVAC Trade 

Contractor. 

Company Rep’s Initials ________ 

Trade Contractor’s Initials ________ 

221 
Post-Work Inspection Checklist: 

To be completed before Trade Contractor leaves jobsite: 

1. If applicable, all site details match the Company’s Framing Layout Plans. 

2. All capillary breaks to be installed by the Framing Trade Contractor as set forth in the 

Framing Requirements and associated Details are in place. 

3. Any structural or insulating sheathing is free from damage (holes). Sheathing has been 

installed according to manufacturer’s requirements, and is in accordance with Framing 

Standards and Description of Work Performance, Framing Requirements, and Company 

specifications. 

4. All site details match the associated Details in the Framing Requirements. 

5. All framing cavities that will receive drywall and separate conditioned space from 

unconditioned space have five-sided containment. All framing cavities that will not 

receive drywall and separate conditioned space from unconditioned space have been 

insulated and have six-sided containment. 

6. All air sealing measures to be performed by the Framing Trade Contractor as set forth in 

the Framing Requirements and associated Details have been installed. 

7. No unapproved framing material substitutions have been made from The Company

specifications. 

Company Rep’s Initials ________ 

Trade Contractor’s Initials ________ 

222 
Mixed-Humid Climate Drainage Plane Requirements and Checklists 

Drainage Plane Requirements 

1. Introduction: High-Performance Drainage Plane 

High Performance is defined as superior energy efficiency, safety, comfort, and durability. 

Managing the flows of moisture and air with the same thoroughness as energy protects against 

the major damage functions a home faces— heat, water, radiation (ultraviolet) and biological 

organisms (frequently requiring liquid water). 

The work of the Drainage Plane Trade Contractor contributes to high performance in the 

following ways: 

• Water management – 

o Provides a barrier to prevent rain water that penetrates the finished exterior 

cladding system, from entering the wall assembly or being introduced into 

window or door openings 

o Provides a pathway for liquid water that has penetrated the cladding system or 

accumulates due to daily or seasonal changes in thermal and humidity levels 

behind the cladding system to safely exit the exterior wall assembly 

• Integrity and Continuity of the Thermal Barrier – 

o The drainage plane, when properly sealed, can also reduce airflow through the 

wall assembly, which improves the thermal performance of the cavity insulation 

• Integrity and Continuity of the Air Barrier – 

o The drainage plane, when properly sealed, can function as an airflow retarder 

• Vapor management – 

o The rate at which water vapor flows into and out of the wall assembly is based in 

part on the material properties of the drainage plane. 

Construction is a process that involves sequential work performed by a variety of subcontractors. 

The Drainage Plane Trade Contractor’s work is generally preceded by The Foundation Trade 

Contractor and The Framing Contractor with these high performance implications: 

• Foundation insulation – protect this material and replace as necessary when damaged as 

the result of framing work. 

• Foundation drainage system – protect this system and replace as necessary when 

damaged as the result of framing work. 

• Sheathing materials installed by The Framing Contractor are key elements of the airflow 

retarder and the thermal insulation – protect these components and replace or repair as 

necessary if damage during installation of the drainage plane. 

223 
The Drainage Plane Trade Contractor’s work is generally followed by The Window Trade 

Contractor, The Insulating Contractor and later by The HVAC Contractor with these high 

performance implications: 

• Flashing and/or weather-resistive barriers installed in rough window and door openings 

must integrate with window and door unit flashings, particularly at the sill and head. 

• Flashings at roofs wall intersections and at penetrations through the wall (i.e. plumbing, 

electrical, vents, HVAC refrigerant lines, etc.) that are provided by other trades must be 

integrated with the drainage plane to keep water from entering the wall assembly. 

• Framing, sheathing and airflow retarder components, IF installed by the Drainage Plane 

Trade Contractor, must be properly installed to permit full insulation of building cavities 

in an airtight manner. 

Performance testing is often a key step along the path to high performance. Drainage plane 

installation may be tested for water management performance by spray rack or hose testing. This 

test would take place after the drainage plane has been integrated with the window/door 

installations but before the installation of cavity insulation. Successful test results are leak-free 

drainage plane installations. 

The Drainage Plane Trade Contractor will be responsible for correcting deficiencies in 

installation so that performance meets the requirements of The Company and high performance 

in these Scopes. The cost of corrective action is the responsibility of The Drainage Plane Trade 

Contractor. 

For more comprehensive information on the relationship between the drainage plane and high 

performance homes, see the following resources: 

• Builder’s Guide to Mixed-Humid Climates (August 2005) specifically Chapter 2 

• Water Management Guide (WMG, May 2006) 

• Building America Best Practices Series Volume 4 

(www.nrel.gov/docs/fy05osti/38448.pdf) 

• Designs That Work – Mixed-Humid Climates 

(www.buildingscience.com/designsthatwork/default.htm) 

224 
 2. Detailed Installation Requirements 

a. Drainage Plane After Window Installation

 Pre-Work and Post –Work Inspection checklists will be completed and signed by Site

Superintendent and The Drainage Plane Trade Contractor 

1. Use the specified drainage plane material, fasteners and sealant or tape. 

2. Install according to manufacturer’s instructions. 

3. Install drainage plane continuously from the bottom to the top of the assembly. (WMG, 

May 2006): page 39). 

4. Weather lap the drainage plane so that the bottom of upper sheets or sections extends over 

the top of the bottom sheet by a minimum of three inches for horizontal joints. Weather 

lap vertical joints by a minimum of six inches. Alternate lapping dimensions may be 

required based on specific manufacturer’s installation instructions. 

5. Below windows or other penetrations, the drainage plane is installed underneath (interior 

to) the bottom edge of the sill flashing (WMG, May 2006): Step 9, page 42.); the 

minimum over lap of the drainage plane material over the flashing at the head of the 

window is three inches (WMG, May 2006): Step 12, page 43). 

6. Above windows or other penetrations, the drainage plane material is installed over 

(exterior to) the top edge of the head flashing. 

7. Flash all wall penetrations, including but not limited to those penetrations for wires, pipes 

and vents, with the flashing materials or blocks specified by The Company. (WMG, May 

2006): pages94-96). 

8. Terminate the drainage plane at the correct location as shown on the details and sequenced 

drawings, providing a pathway for water to leave the assembly. 

9. Lap the drainage plan over all flashings provided by the Roofing Trade Contractor, 

providing a pathway for water to leave the assembly (WMG, (May 2006): pages 87 & 88) 

Details and Sequenced Drawings 

Refer to flashing and drainage plane installation details contained in Builder’s Guide to 

Mixed-Humid Climates (August 2005) and the Water Management Guide (May 2006). 

225 
Pre-Work Inspection Checklist - Drainage Plane After Window Installation 

To be completed before the Trade Contractor starts work on the jobsite: 

1. Construction is at the appropriate stage and conditions are acceptable for The Trade

Contractor to begin work. 

2. Sheathing is installed and attached per Framing SOW.

 3. Windows are installed and properly flashed. 

3. Appropriate materials and equipment are onsite for work to be performed by The Drainage 

Plane Trade Contractor.

 4. The Drainage Plane Trade Contractor has current plans. Date of plans: [___/___/___]

 5. The Drainage Plane Trade Contractor has current Company specifications for all drainage 

plane and drainage plane accessories materials. 

6. The Drainage Plane Contractor has reviewed and accepts all High Performance Drainage 

Plane Requirements listed in the Introduction to the Drainage Plane Requirements and 

Checklists. 

7. The Drainage Plane Trade Contractor has reviewed and understands/accepts the Detailed 

Installation Requirements 2.a “Drainage Plane-After Windows Installation.” 

Company Rep’s Initials ________ 

Trade Contractor’s Initials ________ 

226 
Post-Work Inspection Checklist: Drainage Plane After Window Installation 

To be completed before Trade Contractor leaves jobsite: 

1. The drainage plane is installed in a weather lapped manner. 

2. The drainage plane sections overlap a minimum of three inches for horizontal joints and 

six in. for vertical joints. 

3. The manufacturers recommended or Company specified fasteners were used to attach the 

drainage plane. 

4. Joints between sections of the drainage plane are properly taped (if called for in the 

Detailed Installation Requirements 2.a. “Drainage Plane After Windows Installation”). 

5. The drainage plane properly integrates with the flashing at windows, doors, roof wall 

intersections, and other penetrations: 

 The drainage plane below windows, doors, and other penetrations is installed under 

(interior) to the bottom of the flashing. 

 The drainage plane above windows, doors, roof wall intersections, and other 

penetrations is installed over (exterior) to the top of the flashing. 

6. All site details match the Drainage Plane Details in the Drainage Plane Installation 

Checklist and Details – SOW #2. 

7. No unapproved drainage plane material substitutions have been made from The Company 

specs. 

8. The Drainage Plane Trade Contractor understands that final performance evaluation of 

the drainage plane may be dependent on performance tests (water testing) that The 

Company may conduct at any time in the construction process once the Drainage Plane 

Trade Contractor’s work is complete. 

Company Rep’s Initials ________ 

Trade Contractor’s Initials ________ 

227 
2. Detailed Installation Requirements – 

b. Drainage Plane Before Window Installation 

 Pre-Work and Post –Work Inspection checklists will be completed and signed by Site

Superintendent and The Drainage Plane Trade Contractor 

1. Use the specified drainage plane material, fasteners and sealant or tape

 2. Install according to manufacturer’s instructions. 

3. Install drainage plane continuously from the bottom to the top of the assembly. 

4. Weather lap the drainage plane so that the bottom of upper sheets or sections extends over 

the top of the bottom sheet by a minimum of three inches for horizontal joints. Weather 

lap vertical joints by a minimum of six in.. Alternate lapping dimensions may be required 

based on specific manufacturers installation instructions. 

5. Terminate the drainage plane at the correct location providing a pathway for water to leave 

the assembly. 

6. Flash all wall penetrations, including but not limited to those penetrations for wires, pipes 

and vents, with the flashing materials or blocks specified by The Company. 

7. Cut the drainage plane at openings for windows and doors, according to the Details and 

Sequenced Drawings, in preparation for the installation of windows and doors. 

8. Lap the drainage plan over all flashings provided by the Roofing Trade Contractor, 

providing a pathway for water to leave the assembly (WMG May 2006): page 87 & 88) 

Company Rep’s Initials ________ 

Trade Contractor’s Initials ________ 

2.b. Details and Sequenced Drawings 

Refer to flashing and drainage plane installation details contained in EEBA Builder’s Guide 

to Mixed-Humid Climates (August 2005) and the Water Management Guide (May 2006). 

228 
Pre-Work Inspection Checklist - Drainage Plane Before Window Installation 

1. Construction is at the appropriate stage and conditions are acceptable for The Trade

Contractor to begin work. 

2. Sheathing is installed and attached per Framing SOW.

 3. Appropriate materials and equipment are onsite for work to be performed by The Drainage 

Plane Trade Contractor.

 4. The Drainage Plane Trade Contractor has current plans. Sign off on date of plans: 

[___/___/___]

 5. The Drainage Plane Trade Contractor has current Company specifications for all drainage 

plane and drainage plane accessory materials. 

7. The Drainage Plane Contractor has reviewed and accepts all High Performance Drainage 

Plane Requirements listed in the Introduction to the Drainage Plane Requirements and 

Checklists. 

8. The Drainage Plane Trade Contractor has reviewed and understands/accepts the Detailed 

Installation Requirements 2.a “Drainage Plane-Before Windows Installation.” 

Company Rep’s Initials ________ 

Trade Contractor’s Initials ________ 

229 
Post-Work Inspection Checklist - Drainage Plane Before Window Installation 

1. The drainage plane is installed in a weather lapped manner. 

2. The drainage plane sections overlap a minimum of three inches for horizontal joints and 

six in. for vertical joints. 

3. The manufacturers recommended or Company specified fasteners were used to attach the 

drainage plane. 

4. Joints between sections of the drainage plane are properly taped (if called for in Detailed 

Installation Requirements 2.b.). 

5. The drainage plane properly integrates with the flashing at roof wall intersections, and 

other penetrations: 

 The drainage plane below penetrations is installed under (interior) to the bottom of the 

flashing. 

 The drainage plane above roof wall intersections, and other penetrations is installed 

over (exterior) to the top of the flashing. 

6. All site details match the Drainage Plane Details in the Drainage Plane Installation 

Checklist and Details 2.b. “Drainage Plane Before Window Installation.” 

7. No unapproved drainage plane material substitutions have been made from The Company 

specs. 

8. The Drainage Plane Trade Contractor understands that final performance evaluation of 

the drainage plane may be dependent on performance tests (water testing) that The 

Company may conduct later in the construction process after windows and doors have 

been installed. 

Company Rep’s Initials ________ 

Trade Contractor’s Initials ________ 

230 
Mixed-Humid Climate Windows – Requirements and Checklists 

Window Installation Requirements: 

1. Introduction – High Performance Window Installation 

High Performance is defined as superior energy efficiency, safety, comfort, and durability. Managing 

the flows of moisture and air with the same intensity as energy protects against the major damage 

functions a home faces— heat, water, radiation (ultraviolet) and biological organisms (frequently 

requiring liquid water). 

The work of the Window/Door Trade Contractor contributes to high performance in the following 

way: 

• Water Management – Proper integration of unit flashing, rough opening flashing, and the 

weather-resistive barrier create a continuous drainage plane keeping liquid water out of the 

wall assemblies and moving water off of the wall assemblies. 

Construction is a process that involves sequential work performed by a variety of subcontractors. The 

Window/Door Trade Contractor’s work is generally integrated with the work of the Drainage Plane 

Trade Contractor with these high performance considerations: 

• The flashing systems and components of both the rough openings and the window/door units 

must properly integrate with the work of the Drainage Plane Trade Contractor, regardless of 

whether the window/door unit installation takes place before or after the work of the Drainage 

Plane Trade Contractor. 

The Window/Door Trade Contractor’s work is generally followed by the Air Sealing/Insulation Trade 

Contractor and the Wall Cladding Contractor with these high performance implications: 

• The window/door units are adequately shimmed so that minimally-expanding foam insulation 

can be installed between the rough opening and the unit to contribute to both thermal and air 

barrier continuity. 

• Depending upon the type of wall cladding, the window/door flashing system may need to be 

integrated with the wall cladding for proper water management. 

Performance testing is often a key step along the path to high performance. Window/door installations 

may be tested for water management performance by spray rack or hose testing. This test would take 

place after the window/door installations have been integrated with the weather-resistive barrier but 

before the installation of cavity insulation. Successful test results are leak-free window or door 

installations. 

The Window/Door Trade Contractor will be responsible for correcting deficiencies in installation so 

that performance meets the requirements of The Company and high performance in these Scopes. The 

cost of corrective action is the responsibility of The Window/Door Trade Contractor. 

For more comprehensive information on the relationship between window/door installation and high 

performance homes, see the following resources: 

231 
• Water Management Guide (WMG, May 2006)) 

• Builder’s Guide to Mixed-Humid Climates (August 2005) 

• Building America Best Practices Series Volume 4 (www.nrel.gov/docs/fy05osti/38448.pdf) 

• Designs That Work – Mixed-Humid Climates 

(www.buildingscience.com/designsthatwork/default.htm) 

NOTE: Because window installation can take place before or after the weather-resistive barrier 

(depending on a number of factors including variations in cladding), and because window installation 

is different when installed in conjunction with high performance rigid insulation exterior insulation, 

three different sets of detailed installation requirements follow: 

2a. Windows Installed AFTER the Weather-Resistive Barrier 

2b. Windows Installed BEFORE the Weather-Resistive Barrier 

2c. Windows Installed With Rigid Insulation Exterior Sheathing 

2a. Detailed Installation Requirements – Windows Installed AFTER the WeatherResistive Barrier 

Pre-Work and Post –Work Inspection checklists will be completed and signed by Site

Superintendent and The Trade Contractor

 1. Use the specified windows, flashing and sealant. 

2. Install window according to manufacturer’s instructions flashing the opening and window using 

the detailed written instructions and drawings in this document 

Details and Sequence Drawings 

1. Insert backdam using material specified by The Company. (WMG, May 2006): Step 3, page 29) 

2. Cut the house wrap drainage plane above the window; temporarily tape the house wrap above 

the window up and out of the way. (WMG, May 2006): Step 3, page 29) 

3. Insert the 2 pieces of adhesive backed sill flashing. The vertical leg of the flashing must be at 

least 6 inches in length. The interior edge of the flashing must be on top of the back dam. 

(WMG, May 2006): Step 4, page 29 and Step 5, page 30) 

4. Install the corner patches of adhesive flashing. (WMG, May 2006): Step5, page 30) 

5. Install window, level and attach according to manufacturer’s instructions. 

6. Install jamb flashings followed by head flashing. (WMG, May 2006): Step 7 - 8, page31) 

7. Remove tape and bring house wrap above window back to its original position and tape the 

heading flashing. (WMG, May 2006): Step 9, page32 

8. Install corner tape patches at head and air seal around entire perimeter on the interior with 

sealant or non-expanding foam. (WMG, May 2006): Step 10, page32) 

Form will be signed by The Trade Contractor thereby indicating that all work has been completed in 

the manner specified within this Scope of Work. 

232 
2b. Detailed Installation Requirements – Windows Installed BEFORE the WeatherResistive Barrier 

Pre-Work and Post –Work Inspection checklists will be completed and signed by Site

Superintendent and The Trade Contractor

 1. Use the specified windows, flashing and sealant. 

2. Install window according to manufacturer’s instructions flashing the opening and window using 

the detailed written instructions and drawings in this document 

Details and Sequence Drawings 

1. Insert backdam using material specified by The Company. (WMG, (May 2006): Step 2, page 38) 

2. Mechanically attach (or adhere by removing upper portion of release paper) the sill apron, using 

a piece of flashing, building paper or house wrap (as specified) so that the top edge of the strip 

is flush with the rough opening. The strip should extend 6 in. past each side of the rough 

opening. At least 3 inches at the bottom of this strip must be unattached so that a section of the 

drainage plane can be slipped under later. (WMG, (May 2006): Step 3, page 39) 

3. Insert the 2 pieces of adhesive backed sill flashing as shown in Sequence Drawing Set 2. The 

vertical leg of the flashing must be at least 6 inches in length. The interior edge of the flashing 

must be on top of the back dam. (WMG, (May 2006): Step 4, page 39) 

4. Install the corner patches of adhesive flashing (WMG, (May 2006): Step 5, page 40) 

5. Install the jamb flashings (WMG, (May 2006): Step 6, page 33) 

6. Install the short pieces of flashing under the bottom edge of the jamb flashings and over the sill 

apron 

7. Install a continuous bead of sealant to the backside of the jamb and head flanges. (WMG, (May 

2006): Step 7, page 34) 

8. Install window, level and attach according to manufacturer’s instructions. 

9. Install jamb flashings follow by head flashing as shown in Sequence Drawing Set 2. (WMG, 

(May 2006): Step 8, page 34) 

Form will be signed by The Trade Contractor thereby indicating that all work has been completed in 

the manner specified within this Scope of Work. 

233 
2c. Detailed Installation Requirements – Windows Installed with Rigid Insulation as the 

Exterior Sheathing and Weather-Resistive Barrier 

Pre-Work and Post –Work Inspection checklists will be completed and signed by Site

Superintendent and The Trade Contractor

 1. Use the specified windows, flashing and sealant. 

2. Install window according to manufacturer’s instructions flashing the opening and window using 

the detailed written instructions and drawings in this document 

Details and Sequence Drawings 

1. Insert backdam using material specified by The Company. (WMG, (May 2006): Step 2, page 44) 

2. Insert the 2 pieces of adhesive backed sill flashing as show. The vertical leg of the flashing must 

be at least 6 inches in length. The interior edge of the flashing must be on top of the back dam. 

(WMG, (May 2006): Step 3, page 45) 

3. Install the corner patches of adhesive flashing. (WMG, (May 2006): Step 4, page 45) 

4. Install the jamb flashings. (WMG, (May 2006): Step 5, page 46) 

5. Install a continuous bead of sealant to the backside of the jamb and head flanges. 

6. Install window, level and attach according to manufacturer’s instructions. 

7. Install jamb flashings followed by head flashing. (WMG, (May 2006): Steps 6 – 7, pages 46 – 

47.) 

8. Install a counter flashing over the head flashing as shown in Sequence Drawing Set 3. Use the 

specified material (polyethylene, house wrap or building paper) to create a weatherlapped 

drainage plane from the z-flashing at the horizontal joint in the sheathing above the window to 

the frame of the window. Use short sections of tape to hold this section of the drainage plane in 

place until the cladding is installed. (WMG, (May 2006): page 87.) 

Form will be signed by The Trade Contractor thereby indicating that all work has been completed in 

the manner specified within this Scope of Work. 

234 
Pre-Work Inspection Checklist 

To be completed before the Trade Contractor starts work on the jobsite: 

1. Construction is at the appropriate stage and conditions are acceptable for the Window/Door 

Trade Contractor to begin work, particularly in terms of integrating the weather-resistive 

barrier and both rough opening and window unit flashing. 

2. Exterior wall sheathing is cut flush to (is not proud of) the rough opening. 

3. Appropriate materials and equipment are onsite for work to be performed by the Window/Door 

Trade Contractor.

 4. The Window/Door Trade Contractor has current plans. Record date of plans: [___/___/___]

 5. The Window/Door Trade Contractor has current Company specifications for all window and 

door materials. 

6. The Window/Door Trade Contractor has reviewed and accepts all High Performance

Window/Door Requirements listed in the Introduction to Windows – Requirements and 

Checklists. 

7. The Window/Door Trade Contractor has reviewed and understands/accepts the Window/Door 

Detailed Installation Requirements and Checklists (2.a, 2.b, and 2.c), in particular, the 

importance of thermal and air barrier continuity. 

8. Rough openings for windows and doors are within tolerances provided in the plans and as 

required for installation according to manufacturer’s specifications and the installation 

requirements. 

Company Rep’s Initials ________ 

 Trade Contractor’s Initials ________ 

235 
Post-Work Inspection Checklist 

To be completed after the Trade Contractor has completed all work on the jobsite: 

1. Window/Door unit installation accomplishes/will permit proper integration with the weatherresistive barrier. 

2. Window/Door installation permits proper integration of wall cladding flashings. 

3. Window/door units have not been damaged during installation (mitered corners, flanges, etc.). 

4. All site details match the Detailed Installation Requirements. 

5. No unapproved material substitutions have been made from The Company specifications. 

6. Water testing cannot be conducted until both the window/door and weather-resistive barrier are 

installed. The Window/Door Contractor will be responsible for corrective action if subsequent 

water testing identifies water leakage to the interior that is the result of deficient window/door 

installation. 

Company Rep’s Initials ________ 

Trade Contractor’s Initials ________ 

236 
Mixed-Humid Climate HVAC – Requirements and Checklists 

HVAC Requirements: 

1. Introduction: High Performance HVAC 

High Performance is defined as superior energy efficiency, safety, comfort, and durability. 

Managing the flows of moisture and air with the same thoroughness as energy protects against 

the major damage functions a home faces— heat, water, radiation (ultraviolet) and biological 

organisms (which frequently require liquid water). 

The work of the HVAC Trade Contractor contributes to high performance in the following ways: 

• Water management – The HVAC contractor maintains the integrity of the drainage plane 

by flashing and/or sealing penetrations to the building enclosure made during installation 

of the HVAC system that are not included in the Drainage Plane Contractor’s scope of 

work. 

 Integrity and Continuity of the Air Barrier – The HVAC contractor maintains the 

integrity of the air barrier by air sealing penetrations to the building enclosure made 

during installation of the HVAC system that are not included in the Air 

Sealing/Insulation Trade Contractor’s scope of work. 

 Energy Efficiency – 

o System performance based on the appropriate application of ACCA Manuals J, S and 

D 

o Proper sizing of mechanical equipment, ducts, registers and grilles 

o Air sealing of all ducts and plenums and insulating any ducts not inside conditioned 

space 

o Commissioning HVAC component/systems 

 Safety – 

o Combustion equipment specified and installed to avoid backdrafting and spillage of 

combustion by-products into the occupied space. 

o Outside air ventilation and exhaust systems designed, specified and installed per 

ASHRAE 62.2 – Ventilation and Acceptable Indoor Air Quality for Low-Rise 

Residential Buildings. 

 Comfort – 

o HVAC system maintains operative temperatures and interior relative humidities within 

ranges as established in ASHRAE 55 – Thermal Comfort Conditions for Human 

Occupancy 

o HVAC system is designed, specified and installed to reduce velocity and pressure 

induced noise by properly orientating trunk lines, plenums, and returns; properly 

sizing ducts and register grilles; and installing acoustic lining where necessary. 

 Vapor management – Proper sizing and charging of the cooling system help control 

interior moisture levels, and, where necessary, provide for supplemental 

dehumidification. 

237 
Construction is a process that involves sequential work performed by a variety of subcontractors. 

The HVAC Trade Contractor’s work is preceded by The Framing Trade Contractor and perhaps 

some stages of the Air Sealing/Insulation Trade Contractor, with these high performance 

implications: 

• Framing – constructed according to plans so that all ducts can be installed in their

designed locations within the conditioned space. 

• Air Sealing/Insulation – Air and thermal barrier continuity established by this Trade 

Contractor is maintained as the HVAC equipment and ducts are installed. 

The HVAC Trade Contractor’s work is generally followed by Interior Finish Trade Contractors 

and by finish work of The Plumbing and Electrical Trade Contractors with these high 

performance implications: 

• Duct and duct sealing are not damaged by subsequent Trade Contractors or if damaged, 

repaired or replaced by the HVAC Trade Contractor via notification of the Site 

Supervisor. 

Performance testing is often a key step along the path to high performance. HVAC performance 

tests include but are not necessarily limited to: 

a. an air tightness test to measure the air tightness of the duct system 

b. an air tightness test to measure the air tightness of the entire air distribution system 

(includes ducts and air handler, and may include associated mechanical ventilation ducts 

and equipment) 

c. system air flow test (total and room testing), 

d. room-to-room pressurization test. 

e. refrigerant charge test 

f. temperature rise across furnace heat exchanger 

Successful performance is defined as: 

a. Total system leakage no more than ten percent and duct leakage to the outside no more 

than five percent of the manufacturer’s high speed air handler air flow. 

b. Air flow at supply plenum is within ten percent of manufacturer rating; air flow to each 

room is within 10% of design airflows calculated using ACCA manual J, S &D. 

c. With the air handler on high speed and interior and exterior doors closed, pressures 

across closed doors are less than or equal to 3 Pascals 

d. Superheat method (fixed metering systems) – superheat temperature within 2°F of 

manufacturer recommendation/subcool method (thermal expansion valve systems) - 

subcool temperature within 2°F of manufacturer recommendation 

e. temperature rise across furnace heat exchanger within manufacturers specifications 

The HVAC Trade Contractor will be responsible for correcting deficiencies in installation so that 

performance meets the requirements of The Company and high performance in these Scopes. The 

cost of corrective action is the responsibility of The HVAC Trade Contractor. 

238 
For more comprehensive information on the relationship between HVAC and high performance 

homes, see the following resources: 

• Builder’s Guide to Mixed-Humid Climates (August 2005), specifically Chapter 1, pages 

26 – 30, 44-45, and Chapter 12 

• Building America Best Practices Series Volume 4 

(www.nrel.gov/docs/fy05osti/38448.pdf) 

• Designs That Work – Mixed-Humid Climates 

(www.buildingscience.com/designsthatwork/default.htm) 

• Air Conditioning Contractors of America (ACCA) Manual J, S and D 

239 
2. Detailed Installation Requirements – 

Pre-Work and Post –Work Inspection checklists will be completed and signed by Site 

Superintendent and The Trade Contractor

 1. HVAC equipment is sized per the ACCA Manual J loads, using methodologies described 

in Manual S. 

2. All HVAC delivery components installed per the sizing of ACCA Manual D and located 

per the duct layout plan (See Figure 1 for a sample duct layout plan): 

plenums trunks ducts registers grilles 

3. All HVAC delivery components, including the air handler cabinet, have been sealed with 

mastic. Access panels have been sealed with foil faced UL181 tape after final 

commissioning. 

4. All duct boots sealed with mastic to framing and/or subfloor. 

5. All HVAC penetrations flashed for water management and sealed for air and thermal 

barrier continuity. 

6. All exhaust fans are ducted to the outside. 

7. The mechanical ventilation system installed per The Company specifications (See Figure 2 

for a representative Central Fan-Integrated Supply (CFIS) system set-up). 

8. Confirm with The Company any material or component substitutions from The Company’s 

HVAC specifications. 

240 
Figure E-8. Sample Duct Layout (Building Science Corporation, “Using Wood 

Efficiently: From Optimizing Design to Minimizing the Dumpster,” August 2002) 

241 
Figure E-9. Central Fan Integrated Supply Ventilation (Building Science 

Corporation (www.buildingscience.com/resources/mechanical/fancycling/aircycler_details.pdf) 

Refer to HVAC duct sealing details contained in the Builder’s Guide to Mixed-Humid Climates 

(August 2005), specifically Chapter 12. Additional high performance HVAC design and 

installation guidance can be found at www.cee1.org/resid/rs-ac/hvac.php3. 

Form will be signed by The Trade Contractor thereby indicating that all work has been 

completed in the manner specified within this Scope of Work (SOW) document #2. 

242 
Pre-Work Inspection Checklist 

To be completed before the Trade Contractor starts work on the jobsite: 

1. Construction is at the appropriate stage and conditions are acceptable for The HVAC 

Contractor to begin work. 

2. The HVAC Trade Contractor has current plans. Record date of plans: [___/___/___]

 3. The HVAC Trade Contractor has current Company specifications for all HVAC 

components and systems. 

4. All duct boots sealed with mastic to framing and/or subfloor. 

5. All HVAC penetrations flashed for water management and sealed for air and thermal 

barrier continuity. 

6. All exhaust fans are ducted to the outside. 

7. The HVAC Trade Contractor has completed or has received from The Company an 

integrated HVAC system layout and equipment specifications, designed according to 

ACCA Manual J, S & D. This layout includes room airflow requirements, duct and 

terminal locations, grille and register specifications, ventilation system layout and product 

specifications, and heating/cooling equipment specifications. 

8. If available, the HVAC Trade Contractor has received and reviewed a detailed framing 

layout from The Company and has notified The Company of any conflicts between the 

detailed framing and ducts layouts. 

9. The HVAC Trade Contractor has reviewed and accepts all high performance items that 

appear in the HVAC Standards and Description of Work Performance (SOW #1). 

10. The HVAC Trade Contractor has reviewed and understands/accepts the HVAC 

Installation Details and Checklist (SOW #2). 

Company Rep’s Initials ________ 

Trade Contractor’s Initials ________ 

243 
Post-Work Inspection Checklist 

To be completed before Trade Contractor leaves jobsite: 

1. All HVAC system components and equipment have been installed per The Company’s plans, 

specifications, and the plan-specific ACCA Manual J/S/D. 

2. The following HVAC performance tests have been performed with successful results OR all 

deficiencies leading to the unsuccessful results have been corrected:

 Total system leakage: _[result]_ [passing threshold]

 Air flow at supply plenum: _[result]_ [passing threshold]

 Air flow at supply register(s): _[result]_ [passing threshold]

 System on/door closed pressure differential: _[result]_ [passing threshold]

 Superheat/subcool refrigerant charge test: _[result]_ [passing threshold]

 Furnace heat rise test: _[result]_ [passing threshold]

 3. All site details match the HVAC Details in the HVAC Installation Details and Checklist 

Company Rep’s Initials ________ 

Trade Contractor’s Initials ________ 

244 
Mixed-Humid Climate Air Sealing/Insulation – Requirements and Checklists 

Air Sealing/Insulation Requirements: 

1. Introduction – High Performance Air Sealing/Insulation 

High Performance is defined as superior energy efficiency, safety, comfort, and durability. 

Managing the flows of moisture and air with the same intensity as energy protects against the 

major damage functions a home faces— heat, water, radiation (ultraviolet) and biological 

organisms (frequently requiring liquid water). 

The work of the Air Sealing/Insulation Trade Contractor contributes to high performance in the 

following ways: 

• Integrity and Continuity of the Thermal Barrier – 

o Complete fill of all framing cavities in the conditioned boundary—no voids, no 

gaps 

o Focus on the largest and most common thermal bypasses 

• Integrity and Continuity of the Air Barrier – 

o Continuous air sealing at plates and assembly transitions 

o Complete air sealing at penetrations 

• Vapor management – 

o No substitutions of insulation materials with performance properties (including 

water absorption and vapor permeability) different than the materials specified by 

The Company. 

o Installation of draft stops in areas that will not be accessible after completion of 

framing (outside wall fireplaces, tub surrounds on outside walls, soffits 

terminating on outside walls, vertical chases, etc.) 

o The moisture performance of wall and roof assemblies is a function of the 

combined performance of all assembly components, not the performance of just 

the “vapor retarder” that is traditionally installed behind the interior sheathing 

(drywall). It is likely that your local code or your local code official’s 

interpretation of the code may require the installation of a vapor retarder. 

Consideration should then be given to “smart” vapor retarders to manage vapor 

movement into and out of assemblies, based on local climate conditions. 

o No substitutions of materials with performance properties (including water 

absorption and vapor permeability) different than the sheathing materials 

specified. 

Construction is a process that involves sequential work performed by a variety of subcontractors. 

The Air Sealing/Insulation Trade Contractor’s work is generally preceded by The Framing 

245 
Trade Contractor, The Plumbing Trade Contractor, The Electrical Trade Contractor, The HVAC 

Trade Contractor and The Window Installation Trade Contractor with these high performance 

implications: 

• Framed five-sided cavities to receive insulation – framing and exterior sheathing have 

created five-sided containment for all cavities requiring cavity insulation that will receive 

drywall to create a continuous thermal barrier. 

• Cavities that are to receive thermal insulation in concealed locations that will not receive 

drywall (i.e. behind tubs and showers on exterior walls, chases, fireplaces, etc.) have been 

insulated and an air impermeable barrier has been installed to contain the insulation on all 

six sides. 

• Plumbing/Electrical/HVAC – all plumbing/electrical/HVAC penetrations to the 

conditioned boundary have been made and are ready to be air sealed/insulated. 

• Windows and Doors – All windows and doors have been installed and adequately 

shimmed to permit minimally-expanding spray foam air sealing of rough openings. 

The Air Sealing/Insulation Trade Contractor’s work is generally followed by The Drywall Trade 

Contractor with these high performance implications: 

• All cavity insulation and air sealing details that will be rendered inaccessible by

drywalling have been completed by The Air Sealing/Insulation Trade Contractor. 

• An element of the continuous air barrier may be sealant applied to the backside of all 

drywall at the perimeter of all planes and penetrations (exterior wall outlets, for 

example). This arrangement must be confirmed with The Company and the Drywall 

Trade Contractor 

Performance testing is often a key step along the path to high performance. Homes will be 

tested for building enclosure air leakage with a blower door test. Testing protocols that may 

apply include 100% testing (every installation), random percentage (e.g. 1 in 7) or the reserved 

right to test any installation as determined by The Company or the Site Superintendent. The 

Company reserves the right to further performance test the air sealing and insulation 

performance by infra-red thermal imaging of the building enclosure. Successful performance by 

The Air Sealing/Insulation Trade Contractor is determined by: 

a. Building enclosure air leakage that does not exceed 0.25 CFM/square foot of building 

enclosure surface area at a 50 Pa air pressure differential. 

b. Identification of no significant voids or air leakage upon qualitative infra-red thermal 

imaging of the building enclosure. 

NOTE: “Smoke-testing” during the blower door test and infra-red thermal imaging can help to 

determine if failure to meet the performance test minimum is the result of Air Sealing/Insulation 

Trade Contractor deficiencies or damage to The Air Sealing/Insulation Trade Contractor’s 

work by subsequent trades. Each Trade Contractor agrees to stand by the determination of The 

Company and its performance tests in terms of responsibility for thermal performance. 

NOTE: The EPA ENERGY STAR program has identified 13 of the most common air leakage 

and thermal bypasses. For more information, see: 

www.energystar.gov/ia/partners/bldrs_lenders_raters/downloads/Thermal_Bypass_Checklist.pdf. 

246 
For more comprehensive information on the relationship between air sealing/insulation and high 

performance homes, see the following resources: 

• Builder’s Guide to Mixed-Humid Climates (August 2005) specifically Chapter 3 

• Building America Best Practices for Mixed-Humid Climates 

(www.nrel.gov/docs/fy05osti/38448.pdf) 

• Designs That Work – Mixed-Humid Climates 

(www.buildingscience.com/designsthatwork/default.htm) 

• RESNET Adopted Enhancements to the Mortgage Industry National Home Energy 

Rating Standards Chapter 3.B. 9. Insulation Installation 

247 
2. Detailed Installation Requirements – 

 Pre-Work Inspection: completed and signed by Site Superintendent and The Trade 

Contractor (see Air Sealing/Insulation SOW #3, Trade Contractor & Site Supervisor Pre/Post 

Checklist) 

Detailed Installation Checklist – 

1. Install attic venting insulation baffles to ensure a continuous pathway for soffit-to-ridge 

attic ventilation and to prevent any wind that enters the soffit vents from blowing through 

the insulation material. 

2. Air seal/insulate with the materials as specified by The Company. 

3. Air seal at all the critical junctions in building enclosure assemblies (See Figure 1 below): 

mudsills bottom plates top plates 

4. Air seal/insulate at all rim joists. 

5. Air seal/insulate at all applicable thermal bypasses: 

 shower/tub at exterior wall conditioned space over garage

 attic knee walls attic hatch 

 cantilevered floor duct shafts 

flue shaft piping shaft/penetrations

 dropped ceiling/soffit fireplace on exterior wall

 staircase at exterior wall/attic recessed lighting

 whole-house fan attic penetration walls abutting enclosed but 

unconditioned space 

6. All insulation is installed according to the requirements for Grade I insulation, as defined 

by the “RESNET Adopted Enhancements to the Mortgage Industry National Home Energy 

Rating Standards Chapter 3.B. 9. Insulation Installation:”

 7. Confirm with The Company any air sealing details that are the express responsibility of 

trade contractors whose work follows that of the Air Sealing/Insulation Trade Contractor 

(Drywall Trade Contractor, etc.). 

8. Confirm with The Company any material substitutions from The Company’s air 

sealing/insulation specifications before making any substitutions. 

248 
Details and Sequenced Drawings 

Refer to air sealing and insulation details contained in the Builder’s Guide to Mixed-Humid 

Climates (August 2005), specifically Chapter 11. Additional air sealing details can be found at 

www.buildingscience.com/housesthatwork/airsealing/default.htm and in the Building America 

Best Practices Guide Volume 4 at www.nrel.gov/docs/fy05osti/38448.pdf 

Form will be signed by The Trade Contractor thereby indicating that all work has been 

completed in the manner specified within this Scope of Work (SOW) document #2. 

249 
Pre-Work Inspection Checklist 

To be completed before the Trade Contractor starts work on the jobsite: 

1. Construction is at the appropriate stage and conditions are acceptable for The Air 

Sealing/Insulation Contractor to begin work. 

2. All framing cavities that will receive cavity insulation have six-sided containment. 

3. Roof framing/trusses accommodate [full height/no. of inches] installation of roof/ceiling 

insulation to the outside plane of the top-story exterior walls. 

4. All plumbing/electrical/mechanical penetrations to the building enclosure have been made 

and are ready for air sealing/insulation. 

5. Appropriate materials and equipment are onsite for work to be performed by The Air 

Sealing/Insulation Trade Contractor.

 6. The Air Sealing/Insulation Trade Contractor has current plans. Record date of plans: [ 

___/___/___ ]

 7. The Air Sealing/Insulation Trade Contractor has current Company specifications for all air 

sealing and insulation materials. 

8. The Air Sealing/Insulation Trade Contractor has reviewed and understands/accepts the Air 

Sealing/Insulation Installation Details and Checklist (SOW #2); in particular, the 

importance of thermal and air barrier continuity. 

9. The Air Sealing/Insulation Trade Contractor has reviewed and accepts all high 

performance items that appear in the Air Sealing/Insulation Standards and Description of 

Work Performance (SOW #1). 

Company Rep’s Initials ________ 

Trade Contractor’s Initials ________ 

250 
Post-Work Inspection Checklist: 

To be completed before Trade Contractor leaves jobsite: 

1. Attic insulation baffles and insulation have been installed such that the pathway is the 

specified size allowing unobstructed air flow from soffit to ridge. 

2. All insulation is installed according to the requirements for Grade I insulation, as defined 

by the “RESNET Adopted Enhancements to the Mortgage Industry National Home Energy 

Rating Standards Chapter 3.B. 9. Insulation Installation:” 

3. All assembly transitions and thermal bypasses are air sealed and insulated for thermal and 

air barrier continuity. 

4. Any insulating sheathing is free from damage (holes).

 5. All site details match the Air Sealing/Insulation Details in the Air Sealing/Insulation 

Installation Details and Checklist (SOW #2). 

6. No unapproved material substitutions have been made from The Company specs. 

7. Trade Contractor understands that final performance evaluation of the air sealing/insulation 

is dependent on performance tests (blower door and thermal imaging) that The Company 

may conduct later in the construction process. 

Company Rep’s Initials ________ 

Trade Contractor’s Initials ________ 

251 
Appendix F. SNAPSHOT Form 

252 
References 

ACCA. 2003. Manual J: Residential Load Calculation 8th Edition. Arlington, VA: Air Conditioning 

Contractors of America. 

ACCA. 1995a. Manual S: Residential Heating and Cooling Equipment Selection. Arlington, VA: Air 

Conditioning Contractors of America, Washington, D.C. 

ACCA. 1995b. Manual D: Residential Duct Systems. Arlington, VA: Air Conditioning Contractors of 

America, Washington, D.C. 

ACCA. 1993. Manual T: Air Distribution Basics. Arlington, VA: Air Conditioning Contractors of 

America, Washington, D.C. 

Anderson, R.; Christensen, C.; Barker, G.; Horowitz, S.; Courtney, A.; Givler, T.; Tupper, K. 2004. 

Analysis of System Strategies Targeting Near-Term Building America Energy-Performance Goals 

for New Single-Family Homes: FY 2004 Fourth-Quarter Building America Milestone Report. 

NREL Report No. NREL/TP-550-36920. Golden, CO: National Renewable Energy Laboratory. 

Anderson, R.; Christensen, C.; Horowitz, S. 2006. Program Design Analysis using BEopt Building 

Energy Optimization Software: Defining a Technology Pathway Leading to New Homes with 

Zero Peak Cooling Demand; Preprint. NREL Report No. NREL/CP-550-39821. Golden, CO: 

National Renewable Energy Laboratory. 

ASHRAE. 2004. ASHRAE 62.2-2003. Ventilation and Acceptable Indoor Air Quality in Low-Rise 

Residential Buildings. Atlanta, GA: American Society of Heating, Refrigeration, and Air 

Conditioning Engineers. 

Baczek, S.; Yost, P.; and Finegan, S. 2002. Using Wood Efficiently: From Optimizing Design to 

Minimizing the Dumpster. Westford, MA: Building Science Corporation. 

www.buildingscience.com/resources/misc/wood_efficiency.pdf 

Baechler, M. C.; Love, P. M. 2004. Building America Best Practices Series: Volume 1; Builders and 

Buyers Handbook for Improving New Home Efficiency, Comfort, and Durability in the Hot and 

Humid Climate. NREL Report No. NREL/TP-550-36960. Golden, CO: National Renewable 

Energy Laboratory. 

Baechler, M. C.; Taylor, Z. T.; Bartlett, R.; Gilbride, T.; Hefty, M.; Love, P. M. 2005a. Building America 

Best Practices Series: Volume 2. Builders and Buyers Handbook for Improving New Home 

Efficiency, Comfort, and Durability in the Hot-Dry and Mixed-Dry Climates, Revised. NREL 

Report No. NREL/TP-550-38360. Golden, CO: National Renewable Energy Laboratory. 

Baechler, M. C.; Love, P. M. Building America Best Practices Series: Volume 3, Revised; Builders and 

Buyers Handbook for Improving New Home Efficiency, Comfort, and Durability in Cold and 

Very Cold Climate Regions. NREL Report No. NREL/TP-550-38436. Golden, CO: National 

Renewable Energy Laboratory. 

Building Industry Research Alliance (BIRA); Building Science Consortium (BSC); Consortium for 

Advanced Residential Buildings (CARB); Davis Energy Group (DEG); Florida Solar Energy 

Center (FSEC); IBACOS; National Association of Home Builders Research Center (NAHBRC); 

National Renewable Energy Laboratory (NREL). 2006. Building America Residential System 

Research Results: Achieving 30% Whole House Energy Savings Level in the Hot-Dry and 

Mixed-Dry Climates. NREL Report No. NREL/SR-550-38201. Golden, CO: National Renewable 

Energy Laboratory. 

253 
CABO (Council of American Building Officials). 1995. Mechanical Energy Code 1995. Falls Church, 

VA: Council of American Building Officials. 

CABO (Council of American Building Officials). 1998. Mechanical Energy Code 1998. Falls Church, 

VA: Council of American Building Officials. 

Davis Energy Group. 1993. ACT2 Stanford Ranch Site, Final Design Report. Davis, CA: Davis Energy 

Group. 

DOE (U.S. Department of Energy). 2002. Whole-House Ventilation Systems: Improved Control of Air 

Quality. NREL Report No. NREL/BR-840-26458. 

Griffiths, Dianne, et al. August 23, 2004. Insulation Buried Attic Ducts – Analysis and Field Evaluation 

Findings. 2004 ACEEE Summer Study on Energy Efficiency in Buildings. Pacific Grove, CA: 

American Council for Energy-Efficient Economy (ACEEE). 

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

Quality. Washington, D.C.: BuilderBooks.com. 

Hendron, R. 2005. Building America Research Benchmark Definition, Updated December 29, 2004. 

NREL Report No. NREL/TP-550-37529. Golden, CO: National Renewable Energy Laboratory. 

IBACOS, Inc. November 2004. Community Scale Process Research Results. Pittsburgh, PA: IBACOS. 

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. 

International Energy Conservation Code. 2006. International Energy Conservation Code® 2006. Country 

Club Hills, IL: International Code Council, Inc. 

Judkoff, R., Neymark, J. 1995. International Energy Agency Building Energy Simulation Test 

(BESTEST) and Diagnostic Method. NREL Report No. NREL/TP-472-6231. Golden, CO: 

National Renewable Energy Laboratory 

(www.eere.energy.gov/buildings/tools_directory/software.cfm/ID=85/pagename=alpha_list). 

Lstiburek, Joseph. 2004. Energy and Environmental Building Association. Builder’s Guide to Hot Dry 

Mixed Dry Climates: A Systems Approach to Designing and Building Homes that are Healthy, 

Comfortable, Durable, Energy Efficient and Environmentally Responsible. Westford, MA: 

Building Science Press. 

NAHB Research Center, Inc. November 2002. Performance Comparison of Residential Hot Water 

Systems. Upper Marlboro, MD: NAHB Research Center, Inc. 

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

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

Renewable Energy Laboratory. 

Pigg, S. 2003. The Electric Side of Gas Furnaces. Home Energy Magazine. November/December 2003. 

pp 24 – 28. 

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

RESNET (Residential Energy Services Network). 2002. “Mortgage Industry National Home Energy 

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

Energy Services Network. 

Rudd, A. and H. Henderson: 2005. Monitored Indoor Moisture and Temperature Conditions in Humid 

Climate U.S. Residences. BSC Deliverable KAAX-3-32443-08.B.2 

254 
R.S. Means. 1999. Residential Cost Data – 18th Annual Edition. 1999. Kingston, MA: R.S. Means, 

Company, Inc. 

Shelley, Dean, and Fuller. 1981. Energy Principles in Architectural Design Architects California Energy 

Commission. 

Sustainable Building Industries Council. Sustainable Building Industries Council. Passive Solar Design 

Strategies: Guidelines for Home Building. Sustainable Building Industries Council Website. 

www.psic.org 

U.S. Census Bureau. July 1, 2002, to July 1, 2003. U.S. Census Bureau Housing Unit Estimates (HUEST2003-04), “Annual Estimates of Housing Units for Counties: April 1, 2000, to July 1, 2003.” 

Last revised September 2, 2004. U.S. Census Bureau: Washington, D.C. 

U.S. Department of Energy. January 5, 2005. “House Counts by Climate Zone (detailed)” U.S. 

Department of Energy, Building America House Performance Database. 

Wetter, M. “GenOpt®, "Generic Optimization Program,” Seventh International IBPSA Conference, Rio 

de Janeiro, Brazil. (www.ibpsa.org/proceedings/BS2001/BS01_0601_608.pdf). 

255 
F1146-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)

November 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 Mixed-Humid Climates 

5c. PROGRAM ELEMENT NUMBER

5d. PROJECT NUMBER

NREL/SR-550-39744 

5e. TASK NUMBER

BET7.8004 

6. AUTHOR(S)

Building America Industrialized Housing Partnership (BAIHP), 

Building Industry Research Alliance (BIRA), Building Science 

Consortium (BSC), Consortium for Advanced Residential Buildings 

(CARB), Davis Energy Group (DEG), IBACOS, National Association 

of Home Builders Research Center (NAHBRC), National Renewable 

Energy Laboratory (NREL) 

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

Building America Industrialized Housing Partnership (BAIHP), Cocoa, Florida; 

Building Industry Research Alliance (BIRA), Stockton, California; Building 

Science Consortium (BSC), Westford, Massachusetts; Consortium for 

Advanced Residential Buildings (CARB), Norwalk, Connecticut; Davis Energy 

Group (DEG), Davis, California; IBACOS, Pittsburgh, Pennsylvania; National 

Association of Home Builders Research Center (NAHBRC), Upper Marlboro, 

Maryland 

8. PERFORMING ORGANIZATION 

REPORT NUMBER

KAAX-3-32443-10, 

KAAX-3-33411-10, 

KAAX-3-33412-10, 

KAAX-3-33410-10 

10. SPONSOR/MONITOR'S ACRONYM(S)

NREL 

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

National Renewable Energy Laboratory 

1617 Cole Blvd. 

Golden, CO 80401-3393 

11. SPONSORING/MONITORING 

AGENCY REPORT NUMBER

NREL/SR-550-39744 

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 the Mixed-Humid Climate Region on a costneutral basis. 

15. SUBJECT TERMS

Building America; Whole House Energy Savings; Residential Buildings; Energy Efficiency; Mixed-Humid Climate; 

Systems Engineering Research 

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.

December 2006 • NREL/SR-550-39744

Printed with a renewable-source ink on paper containing at least 50% wastepaper, including 10% postconsumer waste.

Visit our Web sites at:

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Research Toward Zero Energy Homes