Research Toward Zero Energy Homes January 2006 • NREL/SR-550-38201 

Building America Residential System Research 

Results: Achieving 30% Whole House Energy 

Savings Level in Hot-Dry and Mixed-Dry Climates Premier Homes, photo courtesy of Sacramento Municipal Utility District 

T OF ENERGY

DEPARTMEN U 

E 

NITED STAT S OFA ERICA 

M 

U.S. Department of Energy 

Energy Efficiency and Renewable Energy 

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

Building Technologies Program 
Building America Residential 

System Research Results: 

Achieving 30% Whole House 

Energy Savings Level in Hot-Dry 

and Mixed-Dry Climates 

January 2005 – November 2005 

Building Industry Research Alliance (BIRA) 

Stockton, California

Building Science Consortium (BSC)

Westford, Massachusetts

Consortium for Advanced Residential Buildings (CARB) 

Norwalk, Connecticut

Davis Energy Group (DEG) 

Davis, California

Florida Solar Energy Center (FSEC) 

Cocoa, Florida

IBACOS 

Pittsburgh, Pennsylvania

National Association of Home Builders Research Center 

(NAHBRC) 

Upper Marlboro, Maryland

National Renewable Energy Laboratory (NREL) 

Golden, Colorado

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

M. Eastment, and A. Jalalzadeh-Azar 

Prepared under Subcontract No(s). KAAX-3-32443-07, KAAX-3-33411-07, 

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

Subcontract Report 

NREL/SR-550-38201 

January 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. 

Available electronically at http://www.osti.gov/bridge

Available for a processing fee to U.S. Department of Energy 

and its contractors, in paper, from: 

U.S. Department of Energy 

Office of Scientific and Technical Information 

P.O. Box 62 

Oak Ridge, TN 37831-0062 

phone: 865.576.8401 

fax: 865.576.5728 

email: mailto:reports@adonis.osti.gov

Available for sale to the public, in paper, from: 

U.S. Department of Commerce 

National Technical Information Service 

5285 Port Royal Road 

Springfield, VA 22161 

phone: 800.553.6847 

fax: 703.605.6900 

email: orders@ntis.fedworld.gov

online ordering: http://www.ntis.gov/ordering.htm

This publication received minimal editorial review at NREL 

Printed on paper containing at least 50% wastepaper, including 20% postconsumer waste
iii

Table of Contents 

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

Abstract......................................................................................................................................xi 

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

Energy Savings Level in Hot-Dry and Mixed-Dry Climates................................................1 

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 .............................................................13 

Integrated Design Process.............................................................................................13 

Analysis and Design Optimization ...............................................................................13 

Building America Research Benchmark.......................................................................14 

Analysis Methods..........................................................................................................15 

Performance Verification..............................................................................................17 

System Design and Construction Process.............................................................................18 

Climate Analysis...............................................................................................................18 

Key Climate Elements that Affect Building Design.....................................................18 

Site Development..............................................................................................................19 

Orientation Impacts.......................................................................................................19 

Landscaping ..................................................................................................................20 

Water Management.......................................................................................................20 

System Design Approach..................................................................................................21 

Integrated Design Process.............................................................................................21 

Energy Analysis............................................................................................................25 

Passive Design Strategies for Minimizing Cooling and Optimizing Heating ..............27 

Indoor Air Quality Strategies........................................................................................29 

Indoor Air Quality Strategies........................................................................................29 

Heating and Cooling Equipment and Distribution Strategies – Creating Conditioned 

Space for HVAC Systems.............................................................................................34 

First Costs, Cost Tradeoffs, and Owner Annualized PITI + Energy ............................36 

Water Management.......................................................................................................38 

Reducing Construction Waste...........................................................................................41 

Two-Foot Module Design.............................................................................................41 

Value Engineered or “Advanced” Framing ..................................................................42 

Compact Duct Systems.................................................................................................45 

Recycling of Construction Materials ............................................................................46 

Quality Project Management Approach............................................................................47 
iv

Education / Training .....................................................................................................48 

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

Performance Standards—Design, Specifications, Scopes............................................51 

Verification ...................................................................................................................52 

Commissioning .............................................................................................................54 

Feedback Loops ............................................................................................................55 

Quality Management Summary ....................................................................................55 

Building Component Design Details ....................................................................................56 

Building Enclosure Integrity.............................................................................................56 

Control of Heat Flow ....................................................................................................56 

Control of Airflow ........................................................................................................57 

Control of Moisture.......................................................................................................59 

Specific Recommendations...........................................................................................61 

Envelope Systems .............................................................................................................62 

Foundation Systems......................................................................................................62 

Slab on Grade................................................................................................................62 

Crawl Space ..................................................................................................................62 

Building Enclosure Integration Strategies ....................................................................63 

Walls .............................................................................................................................63 

Floors ............................................................................................................................64 

Roof/Ceiling/Attic.........................................................................................................65 

Space Conditioning and Ventilation Systems...................................................................69 

Forced Air .....................................................................................................................69 

Ventilation.....................................................................................................................70 

Air Distribution.............................................................................................................70 

Mechanical, Electrical, and Plumbing Systems................................................................74 

Lighting.........................................................................................................................74 

Major Appliances..........................................................................................................75 

Water Heating and Distribution Systems......................................................................76 

Onsite Power Systems...................................................................................................79 

Cost Analysis ........................................................................................................................79 

Life-cycle Cost Analysis...................................................................................................79 

First-Cost Impacts.............................................................................................................90 

Key Cost Tradeoffs...........................................................................................................91 

Research Results and Conclusions........................................................................................92 

House Case Studies.................................................................................................................100 

Development: Sahara Lake.............................................................................................100 

Development: Armory Park del Sol ...............................................................................114 

Development: Gamlen House.........................................................................................119 

Community-Scale Case Studies..............................................................................................128 

Development: Premier Gardens......................................................................................128 

Development: Lakeside ..................................................................................................133 

Development: Windemere..............................................................................................138 

Appendix A: Passive Solar Design Considerations...............................................................144 

Appendix B: Detailed BEopt Analysis Results......................................................................149 

Appendix C: List of Key Trade-based Certifications ............................................................164 
v

Appendix D: National Housing Quality Rating Table...........................................................169 

Table D.1. Leadership........................................................................................................169 

Table D.2. Strategic Planning ............................................................................................171 

Table D.3. Customer Satisfaction ......................................................................................172 

Table D.4. Performance Management ...............................................................................175 

Table D.5. Human Resources ............................................................................................177 

Table D.6. Quality Construction Processes .......................................................................179 

Table D.7. Supplier Partnerships .......................................................................................181 

Appendix E. National Housing Quality Survey.....................................................................182 

Appendix F. SNAPSHOT Form ............................................................................................185
vi

Definitions 

AC air conditioning 

ACCA Air Conditioning Contractors of America 

ACEEE American Council for an Energy Efficient Economy 

ACH air changes per hour 

ACT2 Advanced Customer Technology Test for Maximum 

Energy Efficiency 

AFUE Annual Fuel Utilization Efficiency 

AH air handler 

AHU air-handler unit 

ALA American Lung Association 

ASHRAE American Society of Heating 

BAP Building America program 

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 

CAEf California Energy Factor 

CAAFUE California Annual Fuel Utilization Efficiency 

CAD computer-aided design 

CDCU Community Development Corporation of Utah 

CEC California Energy Commission 

CFL compact fluorescent bulbs 

CFM cubic feet per minute 

CMU concrete masonry unit 

COP coefficient of performance 

CRI color-rendering index 

CT color temperature 
vii

DHW domestic hot water 

DOE U.S. Department of Energy 

DOE-2 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 

EFL Environments for Living® 

EGUSA Energy-Gauge USA software (FSEC’s residential frontend user interface for DOE-2.1E simulation tool) 

ELA effective leakage area 

EPA U.S. Environmental Protection Agency 

EPS expanded polystyrene 

ERV Energy recovery ventilation 

FF framing factor 

FFA finished floor area 

FG fiberglass 

GenOpt generic optimization program 

HVAC heating, ventilation, and air conditioning 

HERS Home Energy Rating System developed by RESNET 

HM heat mirror 

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 

ICF insulated concrete forms 

IDEC Indirect-Direct Evaporative Cooler 

IDP Integrated Design Process 

IECC International Energy Conservation Code 
viii

IEQ Indoor Environmental Quality 

IOSEU incremental overall source energy use 

JWM John Wesley Miller 

LSL linear strand lumber 

MBH 1,000 Btu/hr 

Mcf million cubic feet 

MEC Model Energy Code 

MEF modified energy factor 

MERV Minimum Efficiency Reporting Value 

Micropas software tool for showing compliance with the California 

Residential Energy Standards 

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 

NREL National Renewable Energy Laboratory 

NZEH net zero energy home 

OA outdoor air 

OASys an indirect/direct evaporative cooler 

oc on center 

OSB oriented strand board 

PA or Pa Pascal 

PATH Partnership for Advancing Technology in Housing 

PEX cross-linked Polyethylene tubing 

PITI principal, interest, tax, and insurance 

PNNL Pacific Northwest National Laboratory 

PSC permanent split-capacitor motors 

PV photovoltaics 

R-Value A measure of thermal resistance used to describe thermal 

insulation materials in buildings 

R.A.P. return-air pathway 

RE recovery efficiency 
ix

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 

SIP Structural insulated panels 

SLA specific leakage area 

SMUD Sacramento Municipal Utility District 

TAB testing, adjusting, and balancing 

TEP Tucson Electric Power 

TIM thermally interrupted metal 

TMY2 Typical Meteorological Year weather data 

TNAH The New American Home 

TOU time of use 

TRNSYS A multidisciplinary software system for preliminary design, 

analysis, and evaluation of space transportation systems 

TXV thermostat expansion valves 

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
x
xi

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. 

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

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

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

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

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

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

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

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

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

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

At a minimum, system energy savings must be achievable at neutral 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 Hot-Dry / Mixed-Dry Climate 

Region on a cost-neutral basis. These research results represent the early starting point for the 

construction of increased numbers of high-performance homes. The broad diffusion of 30% 

homes in the Hot-Dry / Mixed-Dry Climate Region will depend upon a number of other 

factors in addition to the research results presented in this report. Those factors include the 

level of technical support provided by federal, state, and local deployment programs, the 

consumer cost of energy, and the development of policy incentives that support 

implementation of whole-house residential energy-efficiency strategies. 

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

Target 

Energy 

Savings 

Marine Hot Humid Hot-Dry / 

Mixed-Dry 

Mixed 

Humid 

Cold 

30% 2006 2007 2005 2006 2005 

40% 2008 2010 2007 2008 2009 

50% 2011 2015 2012 2013 2014 
xii
1 

Building America Residential System Research Results: 

Achieving 30% Whole House Energy Savings Level 

in Hot-Dry and Mixed-Dry Climates 

Introduction 

About Building America 

Purpose 

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

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

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

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

For innovative building energy technologies to be viable candidates over conventional 

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

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

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

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

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

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

and state and local stakeholders. 

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

including use of systems research techniques1

 and cost and performance trade-offs that improve 

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

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

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

limit residential system energy performance. Building America applies system-research 

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

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

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

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

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

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

that improve house efficiency and performance. 

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

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

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

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

 

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

different system components. 
2 

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

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

community-scale housing takes 3 to 5 years. 

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

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, 

Test Houses 

Community-scale 

Housing 

Pre-production Houses 

Test 

Design

Build

Re-design 

Cost and Performance Trade-offs 

Accelerate Development of 

Advanced Energy Systems 
3 

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. 

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

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

influenced by the program continues to grow over time. 

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

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

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

by 2025 relative to the Building America Research Benchmark2, 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. 

 

2 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.buildingamerica.gov. Hereafter in this report, it is referred to as 

the Benchmark. Hendron, R. 2005. Building America Research Benchmark Definition, Updated December 29, 

2004. NREL/TP-550-37529. Golden, CO: National Renewable Energy Laboratory. 
4 

01234567

US Homebuilding

US Wood Products

US Housing Products

US (Composite)

Foreign (Composite)

Japan (Composite)

Percentage of Sales

Figure 2. Research and Development expenditures3

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 

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

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

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

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

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

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

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

reliability. 

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

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

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

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

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

Climates may not function well in Hot-Humid Climates. 

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

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

Innovation in Housing,4 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 

 

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

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

4 RAND, Building Better Homes: Government Strategies for Promoting Innovation in Housing, 2003
5 

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

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

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 Department of Energy’s 

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 

Department of Energy 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 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 (Table 1) to conduct the systems research required to 

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

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

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

 In 

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

including the completion of more than 30,000 homes. 

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

combining operations research6

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

 

5

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

of energy efficiency solutions and onsite power systems. 

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

performance, based on system constraints. 

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

performance and durability of a system, subject to operating constraints. 
6 

Table 1. Building America Background 

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. 

Start date 1995 

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

Accomplishments to date 1. Developing the Benchmark Definition 

2. Developing protocols for validating wholehouse energy performance 

3. Documenting research and publishing 

Houses That Work, Builder Guides, and Best 

Practices 

4. Increasing the number of ENERGY STAR®

homes 

Current activities Developing integrated cost-effective, wholebuilding strategies to enable new, single-family 

residential buildings to use 30% less total 

energy than the Benchmark in the Cold and HotDry/Mixed-Dry Climate regions. 

Future directions Continuing to develop the strategies for new, 

single-family residential buildings to use 40%-

100% less energy than the Benchmark in the 

Marine, Hot-Humid, Hot-Dry/Mixed-Dry, MixedHumid, and Cold Climate regions 

Projected end date(s) 2025 
7 

 

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

Fail / Pass 

Phase 2: Prototype 

House Evaluations 

Phase 3: Community-Scale 

Evaluations 

 System Research 

Completion Reports 

Development of Advanced

Components

(BT Emerging Technologies, 

Manufacturers, Other EERE 

Offices) 

Phase 1: System 

Performance 

Evaluations 

Pre-phase: Gap 

Analysis, 

Planning and 

Coordination 

Reject 

Post-phase: 

Documentation 

and Resource 

Development

Reject 

Handoff to 

Deployment 

Partners 

Go/No-Go Decision Point: 

Initiation of System 

Research 

Fail / Pass 

Reject Fail / Pass 

Pass / Fail Reject 
8 

The systems research described above is applied in three phases for each climate zone. During 

the three phases, which are conducted in parallel to allow feedback between phases, Building 

America acts as a national residential energy systems test-bed where homes with different 

system options are designed, built, and tested at three levels of system integration, including 

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

validate the reliability, cost effectiveness, and marketability of the energy systems when 

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

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

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

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

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

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

more advanced energy efficiency levels at and above 40% whole-house savings, the 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. 

Table 2. Residential Integration Systems Research Approach 

Phase 1 – System Evaluations 

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

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

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

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

Phase 2 – Prototype Houses 

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

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

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

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

production-ready and capable of being integrated with production construction 

techniques practiced by today’s builders. 

Phase 3 – Community Evaluations 

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

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

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

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

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

climate zone targeted by the program. 
9 

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 the BEopt analysis method.8

 Components must be 

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

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

activities in Phases 2 and 3. 

Documentation and Resource Development 

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

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

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

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

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

and mortgage providers. 

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

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

and financial industries to make the nation’s houses more energy-efficient and affordable. This 

final stage of the process focuses on documentation of best practices and development and 

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

implementation programs. This work supports activities that improve the energy efficiency of 

public and privately owned single-family housing. The program coordinates presentations at 

technical conferences on peer-reviewed, validated, research results and facilitates validation, 

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

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

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

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

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

 

8 Analysis of System Strategies Targeting Near-Term Building America Energy-Performance Goals for New SingleFamily Homes, Anderson, Ren et al. November 2004, NREL/TP-550-36920. 
10 

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

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

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

section details available through the web and other means. 

Building America’s Research Goals 

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

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

To ensure meeting the interim targets along the path to Zero Energy Homes, Building America 

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

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 

Table 3. Building America Research Goals9

Year 

Characteristics Units 

2007 2010 2015 2020 2025 

Average Source Energy 

Savings % 30 40 50 70 90 

Cost $ Zero or Less Net Cash Flow10

Table 4. Building America Performance Targets by Climate Region 

Target 

(Energy Savings) 

Marine Hot Humid Hot-Dry / 

Mixed Dry 

Mixed 

Humid Cold 

30% 2006 2007 2005 2006 2005 

40% 2008 2010 2007 2008 2009 

50% 2011 2015 2012 2013 2014 

 

9

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

Building America Research Benchmark. The targets in Table 4 are updated on an annual basis dependent on 

technical progress and funding. 

10 Life cycle cost, see the benchmark report: Hendron, R. (2005). Building America Research Benchmark Definition, 

Updated December 29, 2004. 43 pp., NREL Report No. TP-550-37529. 
11 

• 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 climate regions. Residential buildings include a limited number of different 

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

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

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

Figure 4. Building America climate regions 
12 

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

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. The severe 

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

of residential growth in those regions. 

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

total energy than the Benchmark for the Hot-Dry/Mixed-Dry and the Cold Climate regions. 

These climate regions present opportunities for research because of the number of new homes 

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

and builder partners for each climate region can be seen in Figure 5. Building America will 

focus on developing the 30% solutions for the Mixed-Humid and Marine regions in 2006. 

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

500,000

Mixed Humid Cold Hot Humid Hot/Mixed Dry Marine

New Homes

0

10

20

30

40

50

60

70

80

90

Builder Partners

New Homes Builder Partners

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

 

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

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

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

Database, January 5, 2005. 
13 

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

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

styles, and price points. 

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

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

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

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

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

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

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

System Approach to Least-Cost Energy Savings 

Integrated Design Process 

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

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

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

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

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

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

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

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

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

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

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

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

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

The final products of each research project include performance measurements and 

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

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

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

are the basis of the recommendations provided in this report. 

Analysis and Design Optimization 

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

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

 

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

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

be found on the Building America website: www.eere.energy.gov/buildings/building_america/PA_Resources.html.
14 

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

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

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

performance between different research projects. 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

government. 

Building America Research Benchmark 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

 

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

15 www.eere.energy.gov/buildings/building_america/pa_resources.html. 16 International Energy Conservation Code®: 2003 Edition with 2004 Supplement. Country Club Hills, IL: 

International Code Council, Inc. 2003, 2004. 

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

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

in Efficiency and Renewable Energy. NREL/TP-550-37731. Golden, CO: National Renewable Energy Laboratory 
15 

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. 

Analysis Methods 

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

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

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

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

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

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

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

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

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

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

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

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

requirements of BESTEST20 in accordance with the software certification sections of the 

RESNET/HERS Guidelines.21

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

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

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

Gas and Electric ACT2 project,22 energy-efficiency measures were evaluated using DOE-2 

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

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

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

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

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

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

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

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

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

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

 

19 This is available for purchase from the Florida Solar Energy Center (http://energygauge.com/). 20 www.eere.energy.gov/buildings/tools_directory/software.cfm/ID=85/pagename=alpha_list 21 Residential Energy Services Network (RESNET). 2002. “Mortgage Industry National Home Energy Rating 

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

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

Energy Group. 
16 

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

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

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

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

methods. 

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

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

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

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

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

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

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

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

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

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

BEopt Analysis Method. 

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

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

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

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

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

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

 

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

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

Conference, Rio de Janeiro, Brazil. (www.ibpsa.org/bs_01.htm). 
17 

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. 

Performance Verification 

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

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

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

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

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

compared to those of the as-built prototype house. 

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

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

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

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

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

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

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

features and uncertain performance characteristics of the house. 

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

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

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

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

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

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

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

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

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

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

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

set. 

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

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

program, because they are generally most interested in whether they meet the overall energy 
18 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

be performed based on actual instead of theoretical operating conditions. 

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

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

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

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

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

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

come. 

System Design and Construction Process 

Climate Analysis 

Key Climate Elements that Affect Building Design 

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

exterior and interior. Sun, rain, temperature, humidity, sunlight, and wind are major 

environmental loads that act on houses. 

The recommendations in this research report are applicable to houses constructed in Hot-Dry and 

Mixed-Dry climate regions. The climate regions have been defined as follows25: 

Hot-Dry: A hot-dry climate is generally defined as a region that receives less than 

20 in. (50 cm) of annual precipitation and where the monthly average outdoor 

temperature remains above 45°F (7°C) throughout the year. 

 

25 www.eere.energy.gov/buildings/building_america/climate_zones.html
19 

Mixed-Dry: A Mixed-Dry climate is generally defined as a region that receives 

less than 20 in. (50 cm) of annual precipitation, has approximately 5,400 heating 

degree days (50°F basis) or less, and where the average monthly outdoor 

temperature drops below 45°F (7°C) during the winter months. 

It should be noted that a section of the Hot-Dry region, stretching from deserts in southern 

California to Phoenix, Arizona, experiences a period of 5-6 weeks in late summer with 

moderately high humidity that is uncharacteristic of this otherwise Hot-Dry region. 

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

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

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

radiation, wind, shade of adjacent buildings, being located on the north side of a mountain, 

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

Site Development 

Orientation Impacts 

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

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

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

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

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

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

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

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

solar orientation is shown in Figure 7. 

Figure 7. Subdivision site plan for solar orientation26

 

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

1981.
20 

Landscaping 

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

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

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

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

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

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

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

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

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

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

reducing one driving force for air infiltration. Trees, shrubs, and vines not only 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 area are constructed and urbanized, surface permeability is reduced, resulting in increased 

storm water run-off volumes that are transported via urban infrastructure (e.g., gutters, pipes and 

sewers) to receiving waters. These storm water volumes contain sediment and other 

contaminants that have negative impact on water quality, navigation and recreation. Furthermore, 

conveyance and treatment of storm water volumes require significant municipal infrastructure 

and maintenance. 

Reduction and treatment of run-off volumes decrease or eliminate contaminants that pollute 

receiving water bodies. Minimizing the need for storm water infrastructure also reduces 

construction impacts and the overall ecological footprint of the building. Finally, infiltration of 

storm water on site can recharge local aquifers, mimicking the natural water cycle. 

Strategies. Storm-water management strategies that prevent or reduce the pollution of water 

include the following: 

• Reduce impervious surface: The most effective method to minimize storm water run-off 

volume is to reduce the amount of impervious area. By reducing impervious area, stormwater infrastructure can be minimized or deleted from the project. To minimize the 

impervious surface and to encourage the natural process of evaporation and infiltration, 

consider such methods as designing a smaller building footprint; clustering or concentrating 

developments to reduce the amount of paved surfaces such as roads, parking lots and 

sidewalks; and paving with pervious materials, such as poured asphalt or concrete with 

incorporated air spaces or concrete unit-paving systems with large voids that allow grass or 

other vegetation to grow between the voids. 

• Storm-water harvesting: 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. 
21 

• For storm-water volumes that must be conveyed from the site to a receiving water body, 

design treatment practices to match the needs of the location and the specific drainage area. 

Design storm-water facilities to remove contaminants and release the volumes to local water 

bodies. Utilize biologically based and innovative storm-water management features for 

pollutant load reduction, such as constructed wetlands, storm-water filtering systems, 

bioswales, bioretention basins, and vegetated filter strips. 

• Use vegetated buffers around parking lots to remove runoff pollutants, such as oil and grit. 

• Specify and install water-quality structures for pretreatment of runoff from surface parking 

areas. Do not disturb existing wetlands or riparian buffers when constructing ponds at the 

lowest elevations of a site. 

• Design storm-water runoff to flow into vegetated swales rather than into structured pipes for 

conveyance to water-quality ponds. Swales provide filtration for storm water volumes and 

require less maintenance than constructed storm-water features. 

System Design Approach 

Integrated Design Process 

Typically a house goes through the following design process: 

• Conceptual Design Development. Planning Stage where the price range, square footage, 

number of stories, lot sizes, general features, and styles are determined. 

• Preliminary Design Development. Develop floor plan sketches, number of bedrooms, 

major options, basic circulation, and function locations, as well as some elevation concepts. 

• Design Development. Preliminary structural, mechanical, electrical, plumbing, and 

Compliance. 

• Construction Documents Development. Final working drawings ready for bidding, 

submittal. Back-checking and coordination by consultants. 

• Construction and Commissioning. 

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

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

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

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

systems-design approach. 

An IDP approach may seem to be an expensive approach, but in the long run the overall costs 

and advantages significantly outweigh the traditional approach. For example, the mechanical 

engineer may be involved in the project much later and be asked to design the mechanical system 

with the already defined constraints of attic/plenum space – resulting in an inefficient HVAC 

distribution system. 

By developing a better IDP, builders are able to incorporate the 30% improvement level 

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

more cost effectively. While use of an IDP at the 30% improvement level for builders is quite 
22 

desirable, it will be even more important at higher energy performance levels, 40%, 50%, and 

70% reduction. 

Approaches to an IDP will vary with different builders, as their relationships with design 

professionals, suppliers, and the trades are often different. For example, a builder with an inhouse architectural staff, that prepares all new house designs, may have a different level of 

control and continuity of design as compared to a builder that works with an independent 

architectural firm. Approaches to the IDP are evolving in Building America’s programs, and a 

single, clearly defined process has not been established. 

An example of this is HVAC system because HVAC designers need to provide input as early as 

possible. They need to tell the architect which architectural features cause comfort issues and are 

difficult or impossible to overcome with typical HVAC practices. They also need to make sure 

the architect allows adequate space to run ducts. Many architects have had to re-design plans 

enough times as a result of HVAC issues that they know fairly well how to accommodate HVAC 

items. Still many problems commonly arise that could be avoided through earlier input and better 

coordination. 

To continue with our example, Table 5 shows the main trades and consultants who are affected 

by the HVAC system. The first column lists the item or issue and each subsequent column how 

each trade is affected by it. 

As shown from the matrix, all trades are intertwined in the design and building process. This 

matrix could be easily applied to the builder, electrician, plumber, etc. As homes become more 

efficient, it will be critical that all involved in the system will need to coordinate their efforts to 

ensure quality control and to employ quality assurance tools and processes through the IDP. 

One model of the information flows and actions associated with an integrated design process are 

shown in Figure 8. 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 moisture performance, comfort, increased durability, and 

reduced risk. All of these issues are typically addressed by following the recommendations 

included in this report. 
23 

Table 5. Matrix of Trades 
24 

Figure 8.27 Model of the information flows and actions associated with an integrated design process 

27 IBACOS, Inc. KAAX-3-33410-06 B.2, Community Scale Process Research Results. Pittsburgh: IBACOS. November 2004

ARCHITECTURE FLOW PURCHASING FLOW

Architecture begins

schematic design

CONSTRUCTION FLOW CONSUL

Design is tested -

focus group or

internally

Yes

MARKETING FLOW

Consumer Focus Group

on Designs at closeout

of product Line

Develop program for

house - size, square

footage, style

Architecture creates

construction program

- structure,

mechanicals, etc.

Design is evaluated

for constructability

Design is reviewed

for cost

Design is evaluated

relative to program

Design

Approved

NO

Architecture 

design develo

Schematic HVAC

with all HVAC

vendors

10% CD Set

Architecture finalizes

schematic design

Diagrammatic

Structural

Spatial layout and

massing

Preliminary Energy

evaluation

Design is tested -

focus group or

internally

Design is evaluated Yes

for constructability

Design is reviewed

for cost

Design is evaluated

relative to program

Design

Approved HVAC layout Architecture begins Construction Documentation

Architecture finalizesDesign Development

Refine Structural

determine exact

dimensions,

materials, and code

compliance

Energy evaluation

NO

Final Energy

Modeling, Structural

& Duct Integration

50% CD Set

Final HVAC Design

R

Product Design

Process

Marketing determines

need for new or refined

product

MKTG / ARCH FLOW

Vendor Evaluation

and Feedback

Vendor Evaluation

and Feedback
25 

Set Goals Early in the Design Stage. By creating specific high-performance goals early in 

the design process, the design and construction team and their external vendors all have a 

clear understanding of the intent and performance metrics associated with a product line. As 

designs are being developed, all systems and strategies are considered, and feedback is 

solicited. This allows for early identification of potential conflicts or opportunities for 

alternate solutions before designs are finalized. 

The goal setting also demonstrates to vendors that the builder has committed to a level of 

performance, and all parties will need to play their role in seeing that it is achieved. A 

recognized best practice found by many of the Building America teams is a commitment to 

vendors to participate in long-term relationships, as opposed to simply forming relationships 

based on the lowest bid. This allows for mutual trust and respect to be built and the 

opportunity to improve and innovate is increased. 

Gain Team-Based Feedback during Design. When asked about the most important design 

issue in its success in achieving higher performance levels, one participating builder identified 

framing as the area that they spend the most time on. The location of every stud, floor truss, 

and roof truss must be specifically located and coordinated with all other trades in order to 

make installation of other systems go smoothly and efficiently. This has been true throughout 

the Building America program. Builders may want to consider use of advanced CAD and 

panelization programs for generating a specific set of architectural and framing plans for each 

house type. It is important to work with the framing and HVAC contractors to identify 

conflicts and develop solutions before houses go into production. 

This process is continually being refined, and a best practice by some builders is to create a 

single system design that would be approved, installed, and warranted by any installing 

contractor. This can apply for many systems in the house, including but not limited to 

framing, electrical, plumbing, and HVAC. For example this level of up-front design with the 

HVAC system helps control consistency and allows for better performance through proper 

sizing and design. It is important to have proper load calculations, equipment selection, and 

duct layouts with documentation that is somewhat transparent, so that HVAC vendors can 

evaluate system design options and agree upon a final solution. At this point, design changes 

can also be made to floor plan and framing layouts that can facilitate duct installation. While 

there is never a perfect solution for all parties, this level of discussion between the vendors, 

design, and construction greatly enhances the opportunity to “get it right.” This process can be 

applied for virtually any system in the house. 

Energy Analysis 

From 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 

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 
26 

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 zone 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 saving,-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 models, 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 uses, 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. 

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.28 Energy 

 

28DOE’s list of energy simulation software can be found at 

www.eere.energy.gov/consumerinfo/reading_resources/v103.html 
27 

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. 

An almost invisible way of incorporating a “passive” strategy that is beneficial in all climate 

zones is the use of low-SHGC glazing in all fenestration units. This product generally has 

little impact on the visual characteristics of the window, and incorporating it does not require 

aesthetic redesign of the house. The 2004 Supplement to the 2003 International Residential 

Code requires a SHGC of 0.4 in the Hot-Dry, Mixed-Dry, Marine, Hot-Humid, and southern 

parts of the Mixed-Humid climate zones. Relatively low (0.30) SHGC glazing has been used 

successfully in 30% improvement homes in all climate zones. While a low SHGC unit reduces 

beneficial heating season solar gain, Building America teams have found that where no 

attention is paid to passive solar design, low-SHGC windows generally provide a costeffective option for builders, when all the systems interactions benefits are considered. The 

following are the reasons for this: 

• Traditional production-builder house models are oriented in any direction. Using 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 avoids some of the need for air conditioner operation, which is a net 

energy savings. 

• Air-conditioning equipment is sized based on peak load. Using lower-SHGC glazing 

reduces peak load and, in turn, reduces air-conditioning unit sizes. Smaller airconditioning systems have lower airflows rates and, therefore, require smaller ducts. 

Lower airflow rates also require smaller fans, which use less electricity to operate. 

Reducing the size of the air-conditioning (AC) system also means cost savings to the 

builder, which can be reinvested in other energy upgrades. 

• The heating season heat gain penalty from the use of lower SHGC glazing only occurs on 

cold, sunny days. As seen in Figure 8A, there is comparably little solar resource across 

much of the northern United States in the winter months; thus, there is little opportunity 

for beneficial solar gain. In those areas of the Cold Climate zone where there is a good 

winter solar resource, higher SHGC windows may be considered, but need to be carefully 

designed to avoid overheating south-facing rooms on sunny winter days and need to be 

properly shaded to reduce solar heat gain in the summer months 

• Use of 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. 
28 

Figure 8A. Average south-facing vertical flat-plate radiation in December for the 

United States 
29 

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 dropping, odors, and other hazardous airborne contaminants. 

There are several approaches to good IAQ: (1) control the generating source, (2) remove the 

contaminant from the indoor air by ventilation or air filtration; and/or, (3) physical cleaning 

(vacuuming, dusting, etc.) 

Source Control. Source control is the most positive approach in the 30% improved homes. 

A number of means of source control have been employed: 

• Control of moisture to remove one of the key support elements for mold growth. This is a 

broad subject and includes application of all of the following principles: 

o Proper flashing details for windows, doors, wall/roof junctions, penetrations of all 

sorts (pipes, ducts, skylights, etc.), attachments (such as porches and decks), offsets 

and projections (such as bay windows) to control the entry of bulk water. 

o Control of envelope condensation potential through appropriate insulation and vapor 

permeability of layers. Appropriate designs must be applied for all components of the 

building envelope, including walls, roof, and foundations. The section of this report 

entitled Cost Analysis discusses climate-specific assemblies. In addition, a builder 

may utilize other regionally specific guidelines, such as the EEBA Builders Guides.29

At a more detailed level, static analysis techniques or dynamic models such as WUFI30

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 Cost Analysis should result in good moisture performance. 

o One wood-frame wall construction detail that has proven quite effective for 

condensation control is to use an exterior insulating sheathing in addition to the 

traditional cavity insulation. During the heating season, this helps to raise the 

 

29 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. 

30 WUFI 2D, Version 2.1. Simulation of heat and moisture transfer. September 2000.
30 

temperature of the interior surface of the sheathing (the first condensing surface) above 

the indoor air dew point. During periods of hot, humid weather, it acts as a vapor 

retarder and helps prevent moist outdoor air from entering the wall, which reduces the 

potential for condensation on the backside of the interior gypsum board in airconditioned 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 unsightly, but they 

also offer an environment for mold growth to occur. This moisture pathway may 

be controlled by forming a continuous capillary break between the ground and the 

concrete foundation system. With monolithic slab-on-grade construction, 

polyethylene sheeting should be placed under the entire slab and footing up to 

grade. With footings poured independent of slabs or with foundation walls, a 

bituminous damp-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-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 
31 

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. 

• 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 Buildings31

• 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: 

 

31 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. 
32 

o Furnaces. Use sealed-combustion units or draft-induced units with dedicated make-up 

air so that the combustion process is atmospherically decoupled from the house itself. 

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

direct-vent, or power-vented types that are atmospherically decoupled from the house. 

o Fireplaces. If fireplaces are installed (gas-fired or solid-fuel-burning) 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 rather rapidly as they dry. Leaving windows open as they are applied 

and dry removes the high initial concentrations. After this initial “dry-out” period, a 

properly designed ventilation system will continue to bring in fresh air and remove further 

off-gassing of pollutants. Thus, for any but highly sensitive occupants, the selection of 

special, low-VOC, materials and finishes is not seen as necessary to achieve the 30% 

whole-house energy-savings level. Should a homeowner have IAQ sensitivity needs, then 

the application of the American Lung Association (ALA) Health House Specifications32 or 

specifications to meet the EPA’s Indoor Air Quality (IAQ) Label33 would be appropriate. 

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

strategy to maintain good IAQ. The desirable range of indoor RH is from 20% in winter 

to 65% in summer, with a preferable range of 30% to 50%. Ventilation strategies play a 

key role in maintaining these ranges and are discussed more fully in the ventilation section 

of this report. However, a variety of ventilation forms, including heat-recovery ventilators 

(HRVs) or energy recovery ventilation (ERVs), are used to remove excess humidity in the 

winter and ERVs, dehumidifying ventilators, dedicated dehumidifiers, and advanced 

HVAC control systems are used to control excess humidity in the summer. The 

importance of winter or summer humidity control, of course, varies with climate region. 

• Pollutant Removal and/or Dilution. Ventilation and air cleaning are the principle methods 

of airborne pollutant removal or dilution. Ventilation system design and strategies are 

treated more fully in another section of this report, but key features relative to good IAQ 

in 30% improvement houses will be noted here. 

o Whole-house mechanical ventilation in accordance with ASHRAE Standard 62.234 is 

recommended. Any of a number of system configurations can meet this requirement 

and include the following: 

– Passive inlet direct to the return-air duct with appropriate dampers and controls 

 

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

www.healthhouse.org/build/Guidelines.asp October 1, 2004. 33 Environmental Protection Agency. Indoor Air Quality Label. Environmental Protection Agency Website. 

www.epa.gov/iaq/energystar/label_specifications.html. 2004. 

34 ANSI/ASHRAE 62.2-2004, Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings 
33 

– Dedicated supply fans designed for continuous operation 

– HRVs or ERVs 

– Dedicated central dehumidifier with ventilation. 

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

the house, particularly bedroom and living areas. This is typically accomplished by 

ducting ventilation air into the heating/cooling duct system. For this distribution to be 

continually effective, however, the HVAC system must be periodically cycled, even in 

no heating/cooling periods. 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. 

o For good IAQ, the HVAC return air stream should be filtered with a 4-in. standard 

filter or a new Minimum Efficiency Reporting Values (MERV)35 6 or 8 normalthickness filters. Ventilation air should also pass through this filter, if possible. Filters 

should be easily accessible for cleaning or replacement and the filter slot should be 

designed so that there is no air bypass around the filter when the HVAC system is 

operating. 

o It is important to provide local exhaust fans for bathrooms, range hoods in the kitchen, 

and exhaust fans in other areas where pollutants may be generated (utility, hobby 

rooms, etc.). All of these fans must be ducted to outdoors via the most direct path. 

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

remain problematic: 

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

– Design of distribution systems is a challenge. Using HVAC ductwork requires 

cycling the central fan, which increases the electric consumption. Dedicated 

ventilation ductwork is quite small and must be well designed to function properly. 

The ventilation air from a dedicated ventilation fan (i.e., ERV, HRV) may not be 

fully distributed to all rooms when only the ventilation airflow is being moved 

through the larger ducts of the central space-conditioning system. 

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

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

– 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. 

 

35 See www.filters-for-home.com/mrev.htm for MERV definitions. 
34 

• 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. 

Heating and Cooling Equipment and Distribution Strategies – Creating Conditioned 

Space for HVAC Systems 

For the 30% improvement house and all new home construction, it is highly recommended 

that the heating and cooling system be designed according to industry standard 

methodologies, most notably ACCA Manual J,36 S,37 D,38 and T.39 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 airhandler 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, the 

recommendation is to use a sealed-combustion furnace or draft-induced unit with dedicated 

make-up air so that the combustion process is atmospherically decoupled from the house itself 

and located in conditioned space, for efficiency and combustion safety reasons. 

 

36 ACCA. 2003. Manual J: Residential Load Calculation 8th Edition. Arlington, VA: Air Conditioning 

Contractors of America. 

37 ACCA. 1995. Manual S: Residential Heating and Cooling Equipment Selection. Arlington, VA: Air 

Conditioning Contractors of America, Washington, D.C. 

38 ACCA. 1995. Manual D: Residential Duct Systems. Arlington, VA: Air Conditioning Contractors of 

America, Washington, D.C. 

39 ACCA. 1993. Manual T: Air Distribution Basics. Arlington, VA: Air Conditioning Contractors of America, 

Washington, D.C. 
35 

A high-efficiency electric heat pump may also be an effective choice for heating, although 

because of the source energy conversion a Heating Season Performance Factor (HSPF) of 

approximately 9.7 is necessary to match the source energy efficiency of a 92% AFUE furnace. 

Where the thermal envelope of the house has been significantly improved, the heating load 

may be dramatically reduced; therefore, 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. 

Air conditioners in Hot-Dry/Mixed-Dry climates should have SEER ratings of 13 or greater, 

which will be code minimum starting in 2006. It should also be noted that there is a wide 

range of cooling requirements in the Hot-Dry/Mixed-Dry climate zone, 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 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 west-facing glass, or a design that 

incorporates low-SHGC glazing and a small number of windows) cooling system run hours 

can be reduced, and smaller capacity equipment will be appropriate. In this climate zone, 

designers should also recognize that because of the minimal latent loads, some of the latent 

capacity in the equipment can be used for sensible load. In general, the sensible capacity 

equals the total capacity when the design wet-bulb temperature of the return air is less than 

59°F. Designers need to check the mean coincident wet-bulb temperature at outdoor design 

conditions and select equipment based on this. This strategy helps to prevent oversizing of the 

equipment. 

Air Distribution Systems. To achieve a 30% whole-house energy reduction, a number of 

requirements apply to design of the duct system: 

• Design should be in accordance with ACCA Manual D. 

• Ductwork should be located within the thermal envelope of the house; in some climate 

zones they may be buried in attic insulation. 

• Ducts should not be located in exterior walls. 

• Ducts must be air-sealed using UL 181-approved mastic or equivalent for the particular 

duct type 

• “Panning” between joists and the use of stud cavities for supply or return air is not 

recommended. 

• Ducts may be of galvanized sheet metal, duct board, or flex duct. 

• There must be continuity of the vapor barrier on insulated ducts not running inside 

conditioned spaces. 

Sometimes duct systems need to run in unconditioned spaces. For a discussion of the 

treatment of these ducts, see the section entitled Space Conditioning and Ventilation Systems. 

To accommodate heating and cooling units and duct systems within the thermal envelope of 

the house, a number of techniques may be employed. This typically affects the architectural 

design of the house and should be considered at the early schematic phase of design. Keeping 
36 

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. 

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 space heating, a hydronic distribution system is 

necessary. These are particularly suited to cold-climate applications where there may not be a 

need for air conditioning and the associated duct-distribution system. Their most common 

configuration is a radiant floor or baseboard convection units. If a radiant floor system is 

selected in a slab-on-grade installation, it is required 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, Cost Tradeoffs, and Owner Annualized PITI + Energy 

Useful and representative costs information for 30% improvements has not been easy to 

determine. In many cases, these are pilot homes and are the first of this level of energy 

performance that have been done by a builder. Thus, the energy-use-reduction construction 

strategies are new to the builder and costs do not represent a mature purchasing structure or 

experienced installation practices. Furthermore, there are often compensating or beneficial 

attributes of the improvement strategies that are not realized until multiple houses are built. 

An example is the ease of air sealing that is inherent with spray-foam insulation systems that 

replaces 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 
37 

• 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 commits to evolving their organizations to the consistent production of quality 

high-performance homes face a transition period. Figure 9 illustrates how the organization 

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

Figure 9. Incremental Cost versus Transformation Stage Curve Incremental Construction Costs 

Transformation Stage 

Indoor Air Quality 

Water Management 

Thermal Enclosure Improvement 

Tighten Ducts 

Integrated Design 

Full-scale implementation 
38 

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. 

Water Management 

Many warrantee issues are associated with water intrusion; therefore, a solid watermanagement 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 

water-management strategy. 

The improvements to the indoor air quality, thermal enclosure, and duct sealing will all 

require additional expense. It is, therefore, important to successfully integrate these strategies 

as quickly as possible. This is where relationships with vendors are critical. Builders must be 

willing to support the trades during the transition; however, trades must take some level of 

responsibility for adapting and developing cost-effective solutions for delivering improved 

performance 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. 

A diagrammatic Incremental Construction Cost versus Transformation Stage curve on a perhouse basis for a builder might be seen in Figure 9. 

It should be noted that this curve is diagrammatic by nature and will vary from builder to 

builder and by region. For example, if a builder has already addressed water management, 

then there is no expected incremental cost associated with this practice. Also note that the tail 

end of the curve still shows some increase in costs. This represents the most conservative 

scenario, where a builder has already optimized many aspects of their houses (i.e., integrated 

advanced framing or does not significantly oversize HVAC equipment). For the consumer, 

this added cost is offset by reduction in utility bills and, as discussed in the section 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. 
39 

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, is included later in this report. 

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; however, the owners are realizing more than $34 

per month in positive cash flow. 
40 

Table 6. Illustrative Incremental Costs of a 39% Energy-Saving House 

Energy Features Energy Features Base Code Title 24 Building America

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

 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:U-Factor

Dual Pane Vinyl Frame Windows w/ Spectrally Selective Glass

 Slider (horz)* 0.673 0.37

 Slider (vert)* 0.673 0.37 Fixed* 0.673 0.33 Patio* 0.673 0.34SHGC 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) YesGas dryer stub YesFluorescent lighting (screw-in lamps) Yes, all downlights2.4kW 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 $107Monthly Amortized Cost $72.32 At a 7% interest rate For 30 years 

Net Monthly Savings $34.68

Energy Features Benchmark Building 

Energy Features Premier Gardens 
41

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 slightly more than 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. 

The following combination of factors have worked to increase the consumption of wood in home 

building: 

• Single-family detached units. A single-family detached home uses more wood per 

household than multi-family housing. According to NAHB, single-family detached units 

went from about 71% of overall housing starts to nearly 80% between 1978 and 2001. 

• Home size. In the past 40 years, the median new home size in the United States has increased 

from 1,365 ft2

 to well over 2,000 ft2, this despite the fact that household size has actually 

decreased by 20%. 

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

convoluted roof lines, and elaborate staircases are common in new homes. 

• Safety standards. We require more of our structures today, particularly in regions with 

seismic and wind considerations. Re-engineering for these loads has resulted in some 

increase in wood-se requirements, but has also spawned site practices that simply “throw 

more wood” at the problem. 

• Lumber versus labor. Just as the relative value of materials versus labor seems to have 

reversed (today, materials are “cheap”—it’s the labor that is “dear”), the typical skills set of 

both designers and framers has diminished, leading to waste at the front and tail ends of 

wood construction. 

• The nature and structure of the industry. Home building is like no other production 

process in the 21st century. Nearly all of the 1.7 million homes built each year are site-built, 

making home building one of the most fragmented of industries in the United States. It is the 

journeymen framers—not architects, engineers or even general contractors—who control 

what and how much wood goes where on the job site. And most training occurs informally, 

by word-of-mouth, during production. 

Two-Foot Module Design 

Starting with foundation layout, the house footprint should be based on 2-foot 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. 
42

Value Engineered or “Advanced” Framing 

There are a number of substantial advantages to optimized framing: it saves time and money up 

front, it improves homebuyer satisfaction, its saves money and energy over the long term, and it 

improves builder image. 

More than 7,000 homes built by Building Science Consortium production builders have used 

advanced framing. The resultant savings in waste are the products of “systems-thinking” and a 

breakdown of age-old myths about how wood framing works. 

The following sections are descriptions of the major optimized framing techniques, with 

appropriate references from the International Residential Code,®40 cited in brackets. 

Frame 24 in. on-center. The prevailing practice is to frame walls, floors, and often roofs at 16-

in. centers. However, 24-in. centers are structurally adequate for most residential applications. 

Even when the stud size must be increased from 2x4 to 2x6, changing spacing from 16 to 24 in. 

can reduce framing lumber needs significantly. See Figure 10 for an example. 

Align framing members and use a single top plate. Double top plates are used principally to 

distribute loads from framing members that are not aligned above studs and joists. By aligning 

framing members vertically throughout the structure, the second plate can be eliminated. Plate 

sections are cleated together using flat-plate connectors. For multistory homes that are framed 

with 2x4s, this may increase the stud size on lower floors to 2x6; however, there is still typically 

a net decrease in lumber used. [Section R602.3.2. of the Code: A single top plate is listed as an 

acceptable option for in-line framing and with properly tied joints.] Figure 11 illustrates the 

alignment of framing and use of single top plates. 

Figure 10. Advanced framing layout showing 24-in. stud centering 

 

40 International Residential Code®: 2003 Edition. Country Club Hills, IL: International Code Council, Inc. 2003. 
43

Figure 11. Advanced framing showing truss 

alignment with stud framing and single top plates 

Size headers for actual loading conditions. Headers are often oversized for the structural work 

that they do. Doubled-up 2x6 (or 4x6) headers end up in non-load-bearing walls. Doubled-up 

2x12 (or 4x12) headers end up in all-load-bearing walls, regardless of specific loading 

conditions. “Load-tuned” headers should be in the vocabulary and practice of all engineers, 

architects, builders, and framers. (Section R602.7.2 of the code. 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. Figure 12 shows a 

ladder-block configuration. 

Use two-stud instead of three-stud corners. Exterior wall corners are typically framed with 

three studs. The third stud generally only provides a nailing edge for interior gypsum board and 

can be eliminated. Drywall clips, a 1x nailer strip or a recycled plastic nailing strip can be used 

instead. Using drywall clips also reduces opportunities for drywall cracking and nail popping, 

frequent causes of builder callbacks. [Figure R602.3(2) of the code 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.] Figure 13 shows various stud corner arrangements. 
44

Figure 12. Example of ladder-block exterior wall intersections 

Figure 13. Wall stud corner configurations 
45

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

non-load-bearing partitions. Nailing directly to the sub-floor provides adequate attachment and 

support. Partitions parallel to overhead floor or roof framing can be attached to 2x3 or 2x4 flat 

blocking. 

Use 2x3s for partitions. Interior, non-load-bearing partition walls can be framed with 2x3s at 24 

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

Compact Duct Systems 

A framing plan can do more than just lay out floor joists. There are opportunities to valueengineer the floor system and obtain a proper joist count, to ensure that all plumbing is 

coordinated with the floor framing, to ensure that all HVAC is coordinated with the floor 

framing, and to ensure that the “stack framing” concept is followed on the job site. Most 

importantly, all these issues are resolved on paper prior to casting the foundation. Figures 14 and 

15 show compact duct system layouts. 

Figure 14. Three-dimensional example of compact duct system41

 

41 Heating and cooling equipment shown in green, return duct shown in blue and supply ducts shown in brown. 
46

Figure 15. Example of a compact duct layout 

Recycling of Construction Materials 

No matter how efficient our use of wood, there will be some waste—cuts-offs from both solidsawn lumber and sheathing. Even for the most efficiently framed buildings, wood waste will be 

one of the largest components of the new construction waste stream. 

Reduced wood purchase and disposal costs. Actual field counts for a production builder in 

California have found a 40% reduction in the cost of a wall-framing package after implementing 

optimized framing methods: a purchase savings for the builder of more than $1,100 on each 

house. Another builder in Maryland reduces total wood waste disposal by 15% using efficient 

framing. 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 
47

translates into 1.1 million acres of clear-cut forest and 30-yard dumpsters lined up end-to-end 

from Phoenix to Chicago! Clearly, builders can achieve and claim significantly reduced global 

and local environmental impact with optimized framing. 

On-site grinding. 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 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 five 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. 

The quality-management approach is an essential element of the Building America approach to 

homebuilding because it is the main vehicle for moving from science and concepts of high 

performance to implementation. The package of tools within the Building America quality 

management approach includes the following: 

• Training/Education 

o For builders 

o For individual trades 

o Certifications 

• Operational Evaluation (Modified NHQ42) 

o Paper Review 

 

42 The NHQ (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. 
48

o Key Player Interviews 

• Performance-Based Standards 

o Design 

o Specifications 

o Scopes 

• Verification Tools 

o Performance Testing 

o Inspections (Checklists) 

• Feedback Loops 

Although this package has not been developed from a single source or as a comprehensive 

system, it certainly could be used as a comprehensive quality project management approach. 

Each of these is discussed in detail below. 

Education / Training 

Builder and Subcontractor Training 

Training has been found to be needed throughout the Building America program. Ongoing 

efforts within the industry will be necessary to develop, deploy, and continually update training 

programs to disseminate information from the Building America program if widespread 

implementation is to take place. While Building America has not been specifically charged with 

the development and deployment of training programs, this section discusses some of the 

opportunities, activities, and issues involved with training at the residential construction industry 

level. 

Builders. The starting point for the quality management approach has always been builder 

training. These have included pre-construction training meetings and site training of trade 

contractors. Each Building America team has conducted such trainings, and their work in the 

context of Building America has led to any number of building-science-based training programs 

in the industry: 

• The Energy & Environmental Building Association’s Houses That Work training 

program. This public-private training partnership has trained hundreds of builders all across 

the country in the principles of climate-based high-performance building science. Several of 

the Building America teams have certified Houses That Work trainers. Although not 

explicitly portrayed as such, the Houses That Work trainings have many of the elements of 

quality management as listed above. 

• The Environments for Living®43 (EFL) Diamond Class Training. Long-time Building 

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

 

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

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

Building America. 
49

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, including Pulte Homes, John Laing Homes, Beazer, Morrison, and others. 

• BECT (Building Energy Code Training). Since 1995, BECT has helped the building 

industry keep up with changes in energy codes. The Building Industry Institute (BII) and 

their subcontractor, ConSol, under contract to the California Energy Commission (CEC) 

began a training program for large production builders in California and Nevada. The 

program has improved compliance with energy standards by improving builders’ 

understanding and implementation of the energy codes. 

The BECT program has trained more than 3,000 contractors and subcontractors in the 

California and Nevada area since its beginnings in the mid 1990s. Through the BECT 

program, California is able to train builders in the following: 

• Current codes and issues 

• Upcoming code changes 

• Construction techniques that improve quality of construction 

• Common enforcement issues. 

California’s energy code has always been at the forefront of implementing energy-efficient 

standards in home building. The energy code’s goal in the beginning was to increase energy 

efficiency of a home being built in California every 3 years by approximately 5%. But since the 

energy crisis, the percentage has been increased to 12% in 2001 and 15% in 2005. Having an 

infrastructure in place like the BECT program has greatly facilitated this dramatic change to the 

building industry. 

Training – Trade Contractors. Each Building America team has conducted trade contractor 

training on climate-specific building science and systems thinking. Targeted trades have included 

framing, insulation, and HVAC. The EFL program conducts trade contractor building science 

training for framing and insulation contractors and is developing an HVAC training module. The 

BETC program in California also provides training to subcontractors. 

Training – Certifications. The Building America program has led at least one of its builders to 

develop its own certification related to high performance. Artistic Homes of Albuquerque, New 

Mexico, certifies its entire sales staff under a high-performance training program. The program is 

called the High Performance Homes Sales Specialist. 

It is not clear at this time if certification of high-performance homebuilding skills from a third 

party group such as the North American Technician Excellence (NATE) or the Building 

Performance Institute (BPI) would be used in the industry. There is time and expense on the part 

of the trade contractor and the individual technician to receive the certification, and this must 
50

then be built into the price of doing business, which ultimately gets transferred to the Builder. 

There may be a correlation with better-trained technicians and reduced callbacks; however, this 

direct link has not been thoroughly researched or documented. 

Feedback from builders who have participated in the Building America program reveals that one 

of the most difficult aspects of sustaining the delivery of high-performance housing is the 

continuous need for trade training and re-emphasizing the performance targets each trade must 

meet. This, in part, can be attributed to the high turnover in the building industry; however, it 

may be that a certification program for high-performance delivery of various key trade activities 

will be necessary for true transformation of the housing industry. A list of key trade-based 

certifications associated with delivery of high-performance housing can be found in Appendix B. 

Operational Evaluation 

Modified from the National Association of Homebuilders Research Center’s National Housing 

Quality program, the Building America operational evaluation is a two-step process to help 

builders evaluate their own operations. The first is a paper review of all the documentation a 

builder has that is associated with its operations and the actual housing being built. The second is 

an interview with key individuals in the company. A reasonable list of the builders’ primary 

source information for the first part of this evaluation includes the following: 

• Annual operating plan. This includes company mission, vision, organizational values, goals 

for each department, strategic objectives, and reporting and other operational guidelines. The 

annual operating plan supports the long-range strategic plan, by documenting specific actions 

and goals that will help the company achieve the strategic plan. 

• Long-range strategic plan. This includes the direction the company is headed, what types of 

barriers might exist, and how these barriers might be overcome. This document is a roadmap, 

which is made more specific in each year’s annual operating plan. 

• Process maps. These include any diagrammatic or written representation of the workflows 

operationally within the company. 

• Design documentation. This category includes construction drawings, scopes of work, 

written specifications, contracts, field guides, etc., that communicate what should be built by 

the vendors. 

• Operational tools. These include any sort of departmental tools used to facilitate business 

processes. For example, construction schedules or other field tools used by site supervisors to 

assist in the day-to-day management of construction or template letters and reports to assist 

in the standardization of company processes. 

• Training programs. This includes any internally developed or externally developed 

program for continuing education of staff within the 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. 
51

• Marketing materials. This includes any type of material used to communicate the builder’s 

message about their product to consumers. 

• Survey mechanisms and results. These include any surveys done by the company or 

outside consultants, which can be for employees, customers, or vendors or can collect 

regional or local information on competitive information, such as sales prices or volume of 

construction. 

A reasonable list of key builder staff to interview as part of the second step in an operational 

evaluation includes the following: 

• Operations 

• Marketing 

• Sales 

• Purchasing 

• Construction 

• Customer Service 

• Human Resources 

• Land Development. 

This two-step process gives a comprehensive understanding of the builder’s current operations. 

This evaluation process could be adopted internally by a builder or externally through the use of 

a consultant in order to identify what areas may need to be addressed if the builder is considering 

transforming their product line to achieve Building America high-performance home technology 

packages. The process is comprehensive, but not overly detailed—it takes approximately 20-30 

hours for one person to work through, once all the data has been assembled. It can identify best 

practices and opportunities without dwelling on minutia. Appendix D contains the latest version 

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

Performance Standards—Design, Specifications, Scopes 

Quality is often compared to the three-legged stool (the stool is of little use without all three 

legs). In high-performance home building, quality is only achieved with performance standards 

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

this premise one step further by stating that many performance standards must be climatespecific; indeed even lot-specific when local terrain and environments bring with them additional 

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

Design and Design Review. An effective means of assuring these goals are implemented during 

the planning stages of a project is through a design review of the project, this can be a key 

instrument in making sure the whole energy system is incorporated in the design. It is highly 

unlikely that a home will be designed singularly around the HVAC system, or window 

orientation, or its ability to resist heat. However, these are all factors that go into a home and are 

crucial in getting a house to achieve 30% whole-house energy savings. For this purpose, value 

engineering techniques must be employed to ensure that all the systems in the home cannot only 

be designed to perform at optimum levels but also be coordinated with those involved with 
52

actual construction of the project to make sure that the homes are built practically and as 

intended when designed on paper. 

Each of the Building America teams has conducted dozens of detailed design reviews, resulting 

in resources such as the Building America Houses That Work climate-specific Best Practices, the 

Houses That Work building profiles, the Noisette Home Performance Standards, the draft Risk 

Assessment Protocol, etc. The common ground among these design standards is that they 

respond to climate-specific protection of the energy efficiency, the comfort, the indoor air 

quality, the durability, and the moisture management of each high-performance home. Thus, they 

make up the first leg of the “quality stool”—high performance design. 

Specifications. Specifiers, and subsequently purchasers, rarely take into account the overall 

performance of the home and its systems when making crucial material/component/subsystem 

choices. Standard specifications don’t take into account individual component performance 

variations, much less the impact of single-component choices on assemblies or systems. Various 

Building America projects have addressed this issue. High-performance specifications were 

developed for the EcoVillage Townhome project in Cleveland Ohio.44 These specifications 

could and should be modified and applied to other high-performance home projects. 

Scopes of Work. Even with intelligent design and the right materials, quality can fall short of 

intended performance without the right installation. Production builders generally rely upon their 

scopes of work to achieve the installation required. But, as a rule, these scopes do not reflect 

systems thinking or climate-specific building science. More than one Building America team 

leader has developed project-specific mock-ups (for walls and window installation; for example 

BSC at EcoVillage, IBACOS at Summerset at Frick Park) or detailed installation procedures that 

could and should be used by high-performance builders in their scopes. BIRA, in conjunction 

with the Comfortwise program, has developed and posted high-performance specifications for 

several keytrades, including HVAC and insulation. It would not be difficult, for example, to take 

a well-known industry scopes resource, such as the NAHB BuilderBooks, The Scopes of Work 

Program,45 and develop a customized Building America set of scopes as a comprehensive 

resource that integrates performance and quality. 

Verification 

Verification tools for 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 

 

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

www.buildingscience.com/buildingamerica/casestudies/ecovillage_specs.pdf. 45 Haas Davenport, Linda. 2000. The Scopes of Work Program: Procedures and Standard to Increase Quality. 

Washington, D.C., BuilderBooks.com. 
53

• Using a digital thermometer to measure room-to-room temperature variation 

• Using a low-e detector to verify glazing properties. 

The beauty of these tests is that quantitative metrics can be established that summarize the 

quality of design, materials, and installation for one or more performance attribute. Most 

performance tests for the residential building industry deal with energy efficiency directly and 

then may be indirectly reflective of other performance attributes, such as indoor air quality and 

comfort. But quantitative tests for other performance attributes, such as moisture management 

and durability, are generally not available, at least not in a cost-effective application. For 

verification of these performance attributes, a detailed inspection checklist and visual inspections 

act as a proxy determination of both quality and performance. 

An important consideration in any quality management approach is the cost of verification. The 

primary determinants of at least the initial costs are the number of homes tested—ranging from 

one initial model home to 100% testing of every home built—and what entity does the testing—

either in-house testing, 3rd-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 3rd-party testing the most costeffective strategy in the long run and based on looking at the total costs and total benefits of a 

much more rigorous quality protocol. The Building America Best Practices Guides46 produced 

by Pacific Northwest National Laboratory (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 questions, 

“How do I know when enough is enough? When is our practice a best practice, substandard, or 

overkill?” Builders MUST use their local conditions and past product history (in terms of 

callbacks, legal claims, 1- and 2-year warranty trends) to intelligently manage durability and 

moisture. Proxy, qualitative tools can be applied—such as infra-red imaging of assemblies, water 

testing, and moisture meter readings—but these approaches have not been documented as part of 

the Building America body of research. 

 

46 Baechler, M. C.; Taylor, Z. T.; Bartlett, R.; Gilbride, T.; Hefty, M.; Love, P. M. 2005. 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. 38360. 
54

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. 

Commissioning includes evaluating the building elements to ensure that shade management 

devices are in place, glazing was installed as specified, air-leakage standards have been met—

these are the static elements of the building. Commissioning can also evaluate other claims about 

the construction materials, such as VOC emission content and durability. It is important that the 

products that were specified for the building meet the manufacturer's claims (and are appropriate 

for the project.) 
55

Continuous commissioning ensures that the building operates as efficiently as possible while 

meeting the occupants’ comfort and functional needs throughout the life of the building. 

Continuous commissioning differs from building operation and maintenance. 

Benefits of building commissioning include the following: 

• Energy savings and persistence of savings 

• Improved thermal comfort with proper environmental control 

• Improved indoor air quality 

• Improved operation and maintenance with documentation 

• Improved system function that eases building turn-over from contractor to owner. 

Feedback Loops 

Quality is a process ideally supported by feedback within the corporate structure and across the 

full range of product. Every department—design, construction, purchasing, warranty, sales, and 

marketing—should report performance successes and failures to every department for each and 

every product type, taking full advantage of feedback loops. In reality, many production builders 

set up little incentive for quality of product, erring in favor of quantity of product. But some 

builders are beginning to understand that it is not just how much profit a company can make, but 

how much profit a company retains, once the set-asides for warranty and claims are factored in. 

More than one builder is asking its managers a question like this: 

“If we are currently setting aside about $5,000 for each home we build to cover 

warranty and claims, how much quality management can we afford?” 

Production builders in today’s hot housing market are generally not having trouble making 

profits, just keeping them. If financial incentives can be created for quality of product, the 

reduction in warranty and claims can be used to finance the quality incentive structure. Feedback 

loops are a key element of any such quality management approach. 

Quality Management Summary 

In order to achieve whole-house energy savings of 30% or more, we are managing energy flows 

on, in, and through the structure to such a degree that we must manage the flow of air and 

moisture with equal attention. The links among energy efficiency, comfort, 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 an technical exercise, not a business 

proposition. 
56

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 also not necessary to meet the 30% savings goal. However, it 

is a recommended approach for all new houses from a moisture-control perspective if basements 

are to be intended for occupancy. Installing carpets and other floor finishes over uninsulated 

concrete basement floor slabs often leads to problems with dust mites and mold in floor 

coverings. 

With wood-frame construction, this means exterior walls framed with 2x6 framing where 

cavities are insulated with fiberglass batts, spray-applied cellulose, or low-density spray-applied 

foams. In addition, the exterior 2x6 framing is sheathed with rigid-foam insulating sheathing. 

In general, insulating sheathing is not necessary to meet the 30% savings goal. However, 

insulating sheathing has other significant benefits, particularly in the areas of moisture control. 

Inwardly driven moisture from reservoir claddings, such as brick and stucco, can be controlled 

by insulating sheathing. Additionally, the use of insulating sheathing of sufficient thickness 

allows the removal of interior vapor barriers and vapor retarders, thereby enhancing the inward 

drying of the assembly. In other words “double vapor barriers” can be avoided. 

Insulating sheathing also has cost advantages over oriented strand board (OSB) and plywood 

sheathings when coupled with innovative framing techniques for wind and seismic loadings. 

Reducing heat-flow in wood frame construction can be accomplished by minimizing the amount 

of framing materials through which conductive heat transfer can occur, increasing the cavity 
57

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 has minimum U-values of 0.3 and SHGC values of 0.4 or lower. 

Control of Airflow 

One of the key strategies in the control of airflow is the use of air barriers. Air barriers are 

systems of materials designed and constructed to control airflow between a conditioned space 

and an unconditioned space. The air barrier system is the primary air enclosure boundary that 

separates indoor (conditioned) air and outdoor (unconditioned) air. In multiunit/townhouse/apartment construction, the air-barrier system also separates the conditioned air 

from any given unit and adjacent units. Air-barrier systems also typically define the location of 

the pressure boundary of the building enclosure. 

The air-barrier system also separates garages from conditioned spaces. In this regard, the airbarrier system is also the “gas barrier” and provides the gas-tight separation between a garage 

and the remainder of the house or building. 

Air-barrier systems keep outside air out of the building enclosure or inside air out of the building 

enclosure depending on climate or configuration. Sometimes, air-barrier systems do both. 

Air-barrier systems can be located anywhere in the building enclosure – at the exterior surface, 

the interior surface, or at any location in between. In Cold Climates, interior air-barrier systems 

control the exfiltration of interior, often moisture-laden, air. 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. 
58

The significant disadvantage of exterior air-barrier systems is their inability to control the entry 

of air-transported moisture into insulated cavities from the interior. As a result, most exterior 

air-barrier systems are insulated on their exterior side with rigid or semi-rigid insulations that are 

not sensitive to wind washing. 

An advantage of interior air-barrier systems over exterior systems is that they control the entry of 

interior moisture-laden air into insulated assembly cavities during heating periods. The 

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, 

non-insulating sheathings can be installed in a manner that allows the installation of interior 

gypsum board sheathing over sheathing edges without noticeably altering wall thickness. With 

one-piece manufactured tub/shower enclosures, the entire height of the interior surface of 

exterior walls should be sheathed. This usually requires the installation of cavity insulation 

before the installation of the interior sheathing. 

Where fireplaces are installed on exterior walls, air leakage can be as significant as air leakage at 

tubs and shower stalls. Fireplace enclosure framing should be lined on the interior with rigid 

sheathing material. Such enclosures should be considered as small rooms that are conditioned. 
59

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 c,an have removable covers site-manufactured in a similar manner to removable 

attic access covers. 

Control of Moisture 

Control of Rainwater. The fundamental principle of rainwater control is to shed water by 

layering materials in such a way that water is directed downwards and outwards 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 

downwards and outwards. 

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 

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. 
60

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 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 because of capillarity. This is the main 

reason that damp-proofing (the black tar-like coating) is applied to exterior basement walls. The 

damp-proofing fills in the pores in the concrete and masonry to reduce ground-water absorption. 

The damp-proofing is a capillary break. Under concrete floor slabs, the stone layer combined 

with polyethylene serves a similar function (they act as capillary breaks). Unfortunately, the 

capillary rise through footings is typically ignored. This can be a major problem if foundation 

perimeter wall are finished or insulated. 

In new construction, a capillary break should be installed on the top of the footing between the 

footing and the perimeter foundation wall. This can be done by damp-proofing the top of the 

footing or by installing a membrane at this location. 

The interior insulation and finishing approach must take into account the moisture migrating up 

through the footing. This is best accomplished by installing rigid foam insulation on the interior 

of the assembly to protect the interior finishes. 

The best foams to use have a perm rating of greater than 1 perm for the thickness used. This 

means limiting extruded polystyrene insulation to less than 1-in. thickness for walls (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 upwards to grade. 

Additionally, the exposed portion of slabs must be painted with latex paint to reduce water 

absorption and a capillary break must be installed under perimeter wall framing. 

Control of Water Vapor Flow. The fundamental principle of control of water in the vapor 

form is to keep it out and to let it out if it gets in. 

The following things are discouraged: 

• The installation of vapor barriers on both sides of assemblies (i.e., “double vapor barriers”). 
61

• 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 of 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 shall be maintained at the center of the room or as low as necessary 

to keep the room air next to cool/cold surfaces at less than 70% relative humidity. 

• All building envelope assemblies should include at least one air barrier and one vapor 

retarder surface. 

• All crawl space assemblies should have a continuous impermeable ground cover that 

functions as both an air barrier and vapor retarder. 

• Provide air-barrier systems that control air movement from the interior. 

• Locate vapor diffusion retarders toward the interior of building assemblies and avoid vapor 

diffusion retarders toward the exterior of building assemblies. Where low-permeance 

exterior sheathings are used, temperature of condensing surfaces under heating conditions 

should be controlled (use of insulating sheathings, external insulation), as well as interior 

vapor pressures. 

• Provide secondary air barriers that control wind washing from the exterior. 

• Control interior relative humidities during the coldest portion of the heating season (maintain 

below 35%). 
62

• 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 Hot-Dry/Mixed-Dry climates, the primary slab-on-grade approach involves a 

monolithic slab-grade beam assembly. Post-tensioning in some cases occurs. 

Insulation and Air Infiltration. In Mixed-Dry 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. 

In Hot-Dry climates, the perimeter of the concrete remains uninsulated. 

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. Excessively long-duration interior negative pressures 

should be avoided. A depressurization limit of 5 Pascals is recommended for continuously 

operating exhaust appliances. A depressurization limit of 20 Pascals is recommended for 

intermittent operating exhaust appliances. Only sealed-combustion appliances should installed 

within the pressure boundary of the building enclosure. Passive sub-slab ventilation is 

recommended to reduce atmospheric air pressure soil gas drivers. 

Crawl Space 

Structure. In Hot-Dry/Mixed-Dry climates the primary crawl space approach involves 

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

conditioned crawl spaces and interfere with ground coupling where the ground can act as a heat 

sink during air conditioning. 

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

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

location is preferred from both a constructability perspective and insect-resistance perspective. 
63

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 appliances should be 

installed within the pressure boundary of the building enclosure. Passive sub-ground cover 

ventilation is recommended to reduce atmospheric air pressure soil gas drivers. 

Conditioning of the crawl space should be accomplished by supplying conditioned air to the 

crawl space either via a dedicated duct or via transfer air from the house where a continuously 

operating exhaust fan is used as the pressure driver. 

Building Enclosure Integration Strategies 

Walls 

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

exterior, as well as transfer wind and seismic loads to the foundation. And similarly 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 Hot-Dry/Mixed-Dry climates, the primary structural approach is site-built woodframe-utilizing engineered elements, such as prefabricated lintels, headers, and sheet goods, such 

as OSB, plywood, and gypsum wallboard. 

Resistance to shear loads as a result of wind and seismic events must be provided. The choice of 

construction or framing approaches addressing shear loads should reflect the local conditions. 

For example, houses constructed in low-wind zones can be constructed with wood frame 

assemblies with non-structural sheathings and metal cross braces or wood “let-in” braces. 

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. 
64

Insulation and Air Infiltration. The optimum approach to insulation involves 2 x 6 advanced 

frame walls with insulating sheathing replacing OSB or plywood sheathing. Cavity insulation is 

either unfaced fiberglass batt insulation or damp-sprayed cellulose. 

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

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 the insulating sheathing as a drainage plane and integrating window and doors with the 

insulating sheathing to provide drainage plane continuity. 

Vapor diffusion is addressed by not installing vapor barriers on the interior of assemblies 

constructed in Hot-Dry/Mixed-Dry 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 results in a tighter 

building enclosure. 

Excessive long-duration interior negative pressures should be avoided. A depressurization limit 

of 5 Pascals is recommended for continuously operating exhaust appliances. A depressurization 

limit of 20 Pascals is recommended for intermittent-operating exhaust appliances. Only sealedcombustion appliances should installed within the pressure boundary of the building enclosure. 

Floors 

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

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

to the foundation by functioning as a diaphragm and similarly transfer loads from the roof to the 

foundation. As part of the provision for environmental separation, floor systems have to control 

heat flow, airflow, rainwater, and water-vapor flow. 

Structure. In Hot-Dry/Mixed-Dry 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 insulating sheathing installed exterior to the rim joist as a drainage plane and integrating 

this with the insulating sheathing of the frame assembly, either above or below the floor system 

to provide drainage plane continuity. 

Vapor diffusion is addressed by not installing vapor barriers on the interior of assemblies 

constructed in hot-dry/mixed-dry 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. 
65

Excessive long-duration interior negative pressures should be avoided. A depressurization limit 

of 5 Pascals is recommended for continuously operating exhaust appliances. A depressurization 

limit of 20 Pascals is recommended for intermittent-operating exhaust appliances. Only sealedcombustion appliances should be installed within the pressure boundary of the building 

enclosure. 

Roof/Ceiling/Attic 

The function of roof/attic systems is to provide environmental separation between the interior 

and exterior, as well as to transfer wind and seismic loads to the foundation by functioning as a 

diaphragm. As part of the provision for environmental separation, floor systems have to control 

heat flow, airflow, rainwater, and water vapor flow. 

Structure. In hot-dry/mixed-dry climates, the primary structural approach is site-built woodframing utilizing engineered elements, such as prefabricated roof trusses and sheet goods, such 

as OSB and plywood. 

Insulation and Air Infiltration. The optimum approach to insulation involves blowing 

insulation on the top surface of ceiling gypsum board. This ceiling insulation level is maintained 

throughout the entire plane of the ceiling extending to the perimeter walls. Roof trusses are 

constructed in such a manner as to maintain the thickness of ceiling insulation directly above the 

top plates of the exterior wall framing. Baffles are installed to control wind washing. 

Air infiltration control is provided by an air barrier. The ceiling gypsum board is installed to 

function as an air barrier. Dropped ceiling areas are draftstopped, ceiling light fixtures are 

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

In some hot dry climates, conditioned roof/attic construction may be warranted. 

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

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

Vapor diffusion is handled by providing roof/attic ventilation and by not installing an interior 

vapor barrier. 

Figures 16, 17, and 18 are examples of building envelope details for Albuquerque, New Mexico; 

Sacramento, California; and Tucson, Arizona. 

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 appliances should installed 

within the pressure boundary of the building enclosure. Passive sub-slab ventilation is 

recommended to reduce atmospheric air pressure soil gas drivers. 
66

Figure 16. Example of building envelope details for Albuquerque, New Mexico 
67

Figure 17. Example of building envelope details for Sacramento, California 
68

Figure 18. Example of building envelope details for Tucson, Arizona
69

Space Conditioning and Ventilation Systems 

Forced Air 

Forced-air heating and cooling systems are the most predominant type of system in today’s 

residential new-construction market. This is driven primarily by the market for central air 

conditioning. According to census data, 77% of the homes constructed from 1990 to 1997 had 

central electric air conditioning. Central natural gas-fired furnaces were used in 47% of the new 

homes. 

Cooling system efficiency is important in hot climates because air conditioning represents a 

larger share of annual building energy use than in other climates. However, the 30% 

performance goal is generally achievable by applying air conditioners that meet the 2006 federal 

(NAECA) standard of 13 SEER. This is particularly true if efficient duct systems are employed 

and if cooling loads are reduced by incorporating high performance (Low-E2) windows and 

architectural window shading in the design. 

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

(using ACCA Manuals J and S) 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. Fan 

speed taps should be adjusted to provide close to 400 cfm per ton of cooling capacity; lower 

airflows will provide more latent cooling capacity than is generally needed in hot-dry/mixed-dry 

climates, and higher airflows will waste fan energy. 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. 

Relatively low heating loads in hot-dry/mixed-dry climates mean that high-efficiency 

(condensing) furnaces are not required to achieve the 30% target, though with declining costs for 

90+ AFUE furnaces, they are an increasingly good value. Induced draft, direct-vent furnaces are 

desirable because they can be located in conditioned space, minimizing heat loss. Direct vent 

furnaces draw combustion air directly from outdoors rather than from the surrounding 

(unconditioned) space. 

Air conditioning, heating, and, in some cases, ventilation systems, use the same fan to move air, 

so the efficiency of the furnace or heat pump indoor fan motor can have a large impact on yearround energy use. Nearly all furnace manufacturers offer “variable-speed” brushless permanent 

magnet (BPM) DC motors. Unlike permanent split-capacitor motors, BPM motors retain their 

high efficiency at reduced fan speeds, nearly attaining theoretical cube law reductions in energy 

use. Though they have more than a $200 price premium, they are a recommended means of 

lowering HVAC energy use, particularly with two-stage heating and cooling systems. 

Though not critical to meeting the 30% performance level, locating the forced-air system 

(furnace/air handler and ducts) within the conditioned space will substantially improve wholehouse performance. This approach minimizes the system inefficiencies associated with air 

leakage and thermal losses from the typically leaky system cabinets. Alternative locations for 

the furnace/air handler include a mechanical room, closet, or soffited area that is within 

conditioned space, or in an unvented or “cathedralized” attic. Few production homes are being 
70

built over basements in Hot-Dry/Mixed-Dry Climates, but basements are also a good alternative 

location. 

Air-conditioner energy use can be reduced by ventilating homes at night with cool outdoor air to 

reduce the temperature of building thermal mass. This technique can reduce cooling energy use 

by up to 35% where summer diurnal temperatures vary by 30°F or more, but ventilation cooling 

is not necessary to achieve the 30% savings target. 

Ventilation 

Most new homebuilders in Hot-Dry/Mixed-Dry Climates still rely on building leakage, 

intermittent use of bathroom and range-hood ventilation fans, and occupant use of windows and 

doors for maintaining indoor air quality. A California study to determine the adequacy of this 

approach is currently underway. 

Despite the fact that ventilation systems increase energy use, with new homes being built to 

tighter air-leakage standards, a whole-house mechanical ventilation system that is capable of 

meeting the specifications of ASHRAE Standard 62.2 is recommended to assure adequate indoor 

air quality.47 The relatively low indoor-outdoor temperature differences in Hot-Dry/Mixed-Dry 

climates do not justify the initial expense and operating cost of heat-recovery ventilators. The 

remaining choices for mechanical ventilation include systems that utilize the furnace fan to 

induce the flow of outdoor air into the HVAC system ducts and exhaust fans that operate 

continuously. 

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. 

These systems have the disadvantage of using excessive fan energy during periods when there is 

no demand for heating or cooling, because most of the airflow is recirculated air and only a 

fraction is outside air. Advantages are that that the fresh-air volume can be adjusted to meet 

ASHRAE 62.2 requirements, outside air is filtered, and fresh air is delivered to every space. 

Continuously operating exhaust fans located in a bathroom or central area of the house provide a 

lower cost solution. High-quality “low sone,” efficient fans are typically used for this 

application. Because exhaust fans draw air from leaks in the building envelope, air is not filtered 

and may not be evenly distributed. A better solution that is in use by some contractors is to tie 

all bathroom exhaust ducts together and route them through a single, continuously operating, 

high-efficacy axial fan that is vented to the exterior. An approach that has also been used is to 

terminate a small fresh-air duct inside the return plenum, with a filter applied to the discharge 

opening. The filter is accessible through a hinged filter grill. 

As with all mechanical systems, it is also 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% improvement, a number of requirements apply to design of the duct system: 

 

47 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. 
71

• Design should be in accordance with ACCA Manual D 

• Ductwork should be located within the thermal envelope of the house or buried with 

insulation 

• Ducts should not be located in exterior walls 

• Ducts must be air-sealed using UL 181-approved mastic or equivalent for the particular duct 

type 

• “Panning” between joists and the use of stud cavities for supply or return air is not 

recommended 

• Ducts may be of galvanized sheet metal, duct board, or flex duct 

• There must be continuity of the vapor barrier on insulated ducts not running inside 

conditioned spaces. 

Sometimes duct systems need to run in unconditioned spaces. 

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. 

Sealed Forced-Air Distribution Systems. Leaky duct systems, 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 targets for total duct leakage is 5% of the 

high-speed system-cooling airflow in CFM, as tested at 25-PA reference pressure. To further 

reduce duct leakage, do not pan joists or use stud cavities for supply or return air. It is virtually 

impossible to seal building cavities properly to achieve the target tightness for forced-air 

systems. 
72

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 historically typical in colder climates, but are losing favor because of 

their costs. From a cost-effectiveness standpoint, a well-designed central return system with 

individual room pressure relief is considered the standard for the 30% improvement house. To 

qualify as well-designed, the return system must incorporate adequate relief from each room 

where entry doors may be closed. Thus, return air recommendations include the use of ceiling 

“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 Uvalue and SHGC, and air sealing have been improved to such an extent that basic comfort needs 

are more easily met by the HVAC System. In particular, envelope surface temperatures are 

moderated to a considerable degree, which results in reduced radiant heat loss (or gain) to room 

occupants, improving comfort conditions. Similarly, solar gains through low-SHGC windows 

are reduced, considerably improving cooling season comfort conditions. With good air sealing, 

houses are much less drafty than those built to older construction standards. 

All these reduced loads and improved comfort conditions mean 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 
73

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 to 13 ft away. Ceiling diffusers with curved blades to help direct the airflow along 

the ceiling can be used where the wall opposite the dominant load exceeds 13 ft. 

Research is currently underway in the Building America Program to understand the issues of air 

distribution in high-performances houses and to develop recommendations for supply and return 

apertures to achieve the best comfort conditions consistent with a highly energy-efficient system. 

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 

• Register approach conditions – boots 

• Dampening and control. 

The recommendations that are developed from these ongoing investigations will enhance the 

current recommendations for houses achieving 30% whole-house savings and will likely be 

critical for houses at the 40% and greater improvement levels. 

Duct insulation. If ducts cannot be brought within conditioned spaced, supply ducts should be 

insulated to R-8 minimum and return ducts to R-4 minimum. Research by the Building America 

Team CARB48 has supported code credits for ducts in Hot-Dry and Mixed-Dry Climates that are 

buried in loose-fill attic insulation. This strategy should not be used in sections of this climate 

 

48 Dianne Griffiths et al. August 23, 2004. Insulation Buried Attic Ducts – Analysis and Field Evaluation Findings. 

American Council for Energy-Efficient Economy (ACEEE). 2004 ACEEE Summer Study on Energy Efficiency in 

Buildings. Pacific Grove, CA. 
74

zone with seasonally high levels of humidity with a corresponding need for cooling because 

condensation can form on the outside of the duct vapor barrier and cause moisture problems in 

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

condensation. 

Mechanical, Electrical, and Plumbing Systems 

Lighting 

Compact fluorescent lamps, smaller versions of standard fluorescent lamps, use 70%-75% less 

energy than their incandescent equivalents, and they have brightness and color rendition 

comparable to incandescent lights. They cost more, but last 10 to 13 times longer than 

incandescents, making them very cost effective if used at least 2-3 hours per day. A wide variety 

of sizes and shapes are available with varying color-spectrum characteristics. Consult your local 

lighting supplier/designer, and install them wherever practical. 

The following are near-term energy-savings opportunities for new homes. In some cases, these 

involve newly commercialized products that are just now entering the market, while in other 

cases these represent systems show great promise but need further refinement and field-testing: 

• High-quality, high-output residential grade CFL downlights for kitchens and hallways 

• Linear fluorescent bathroom vanity strips (vertical and/or horizontally mounted) 

• Bathroom occupancy sensors with integrated LED nightlight 

• LED porch lighting 

• LED exterior security luminaire 

• High-output LED walkway lighting 

• Evaluation of energy-savings potential from incandescent dimming. 

Home Lighting Facts. Compact fluorescent lamp use 70%-75% less energy than their 

incandescent equivalents. When replacing a 100-watt incandescent lamp, a 28-watt CFL can be 

used. Here are some facts about CFLs: 

• Compact fluorescents last approximately 10,000 hours, which is 10 to 13 times the life of an 

incandescent lamp (expected life approximately 750 hours). 

• Compact fluorescents are most cost-effective when used at least 2-3 hours per day. 

• Although compact fluorescent lamps may appear different than the common incandescent, 

they fit most standard fixtures found in homes today. The screw-in base is the same on both 

lamps. 

• The typical incandescent lamp wastes 90% of the energy it uses, producing heat rather than 

light. 

• The latest compact fluorescent lamps have improved color rendition. The light is a warm 

tone that is almost identical to that of an incandescent lamp. Most people can't tell the 

difference. 
75

Residential Lighting Controls. Residential lighting controls represents a significant 

opportunity for energy savings. Lighting controls generally refers to technologies that turn off 

(or turn down) lighting systems when they are not needed. Examples include occupancy sensors, 

photo sensors, dimmers, and timers. 

Technologically, residential controls have improved greatly over the last several years, both in 

terms of the types of controls options available, as well as their quality and functionality. As the 

cost of these systems decrease because of increased demand for commercial applications, they 

become increasingly attractive for cost-effective residential applications. 

Recognizing these technological and market advances, as well as the potential energy savings of 

these technologies, energy-code officials have begun to look more closely at residential lighting 

controls. The new 2005 Title 24 building code in California, which will go into effect on 

October 1, 2005, includes strong incentives for homebuilders to utilize occupancy sensors, photo 

sensors, and dimmers. In fact, many market watchers now anticipate that homebuilders will 

choose lighting control alternatives over energy-efficient luminaries to comply with this new 

code because the controls approaches are often more cost-effective. 

Major Appliances 

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

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

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

improvement level. It is also recommended that best-in-class appliance for non-ENERGY 

STAR-rated appliances be installed or recommended for purchase by the homeowner if not 

provided by the builder. 

Program for Off-peak Operation. While not a mechanism for direct source energy reduction, 

peak-load shifting is a beneficial strategy from a consumer-utility cost perspective where 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 off-peak hours and refraining or minimizing their use, especially 

simultaneous use, during peak hours. 

For example, using Whirlpool’s energy management system for stand alone Time-of-Use (TOU) 

appliances delays the operation of the dishwasher, washing machine, and dryer can be delayed 

until the energy prices are lower (off-peak rate). An LED lets the consumer know if the rate is 

currently on- or off-peak. To delay until off-peak, the consumer can press a button and another 

LED illuminates to let them know that this appliance will start at a later time. 

An alternative strategy is to minimize the amount of time that appliances are in the high-power 

mode by ensuring that the appliance is used in the lowest possible power mode when ever 

practical.49

 

49 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. 
76

Water Heating and Distribution Systems 

At the 30% improvement level, energy use for hot 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: 

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 (Figure 19). 

• Establish the design population of the house by taking the number of bedrooms + 1. 

• Multiply this by the gallons/person for the climate zone where the house is located to get the 

first-hour rating for the water heater. 

• Using the first-hour rating from Step 2, select a DHW heater that meets or exceeds this 

rating. 

• For a tank-type gas heater, select a heater with an energy factor greater than 0.60. For a tanktype electric heater, select a heater that meets the current NAECA standard. 

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 sealedcombustion units that draw combustion air from outdoors and fan discharge combustion gasses 

outdoors. If electricity is used for heating water, a high-efficiency tank or tankless unit should be 

used. 
77

Figure 19. Domestic hot water tank sizing for 135°F tank temperature only 

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. 

Tank-type heaters offer the best efficiency with relatively steady, continuous-use patterns. If 

electricity is the energy source for water heating, additional improvements to other areas of the 

house will likely be needed to achieve the 30% savings levels, because there is very little room 

for improvement in electric water-heating efficiency compared to the possible efficiency gains 

using gas-fired technologies. 
78

Stand-alone electric heat-pump water heaters offer better efficiency than electric resistance 

heaters, but they are complex, costly, and still evolving as a standard commercial product. They 

provide the best efficiency when their cold-air discharge can be used to augment home air 

conditions, which can be a benefit in cooling-dominated climates. Conversely, they can 

contribute to an additional heating load during the winter. Optimizing these relationships along 

with this performance variation as a result of supply-water temperature and load pattern is quite 

challenging. Primarily because of the early state of technology deployment and reliability, 

stand-alone heat-pump water heaters are not considered a practical choice at the 30% level. 

Should these units improve in reliability, and 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. In an area where no natural gas is available, this system is an 

option in all climate zones; however, it requires a skilled and experienced installer base and 

favorable pricing. 

While not necessarily required to achieve the 30% whole-house energy-savings target, there are a 

number of reliable solar DHW heaters in the market. They represent a range of operating 

philosophies: 

• Storage/non-storage 

• Freeze-protected/drain-back 

• Passive thermosystem/pumped cycle, etc. 

With good design, these solar systems can all be effective sources of hot water, particularly in 

sunny climates. What most degrades the performance of solar DHW systems are the details of 

design, construction, operation, and maintenance. Research has found that simple set of 

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

usage pattern, can render the solar contributions nearly negligible. Primarily because of their 

high cost, solar DHW systems are not considered practical at the 30% improvement level. 

Hot Water Distribution Systems. The hot water distribution system plays a surprisingly 

important role in the total energy efficiency of the DHW system. Thermal losses from the 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 

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. 
79

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.50

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. 

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 eliminates 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.” 

Onsite Power Systems 

A number of on-site power production systems are currently available for Building America 

projects and others are in the research stage. Most have been used in Building America projects. 

These systems include the following: 

• Photovoltaics 

• Engine generator/combo systems 

• Fuel cells. 

The 30% improvement level can be achieved most cost effectively through the improvement of 

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

of some lighting and appliance improvements. On-site power systems are very costly and are not 

recommended as a strategy to achieve the 30% savings level. 

Cost Analysis 

Life-cycle Cost Analysis 

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

optimum that balances investments in efficiency versus utility bill savings. However, there are 

 

50 NAHB Research Center, Inc. November 2002. Performance Comparison of Residential Hot Water Systems. 

Upper Marlboro, MD: NAHB Research Center, Inc. 
80

sometimes non-economic reasons for targeting a particular level of energy savings. Given a 

particular energy-savings target, economic optimization can be used to determine the optimal 

design (lowest cost) to achieve the energy-savings goal. The analysis presented below targets 

30%-39% whole-house energy savings with respect to the Benchmark by using the BEopt 

analysis method to investigate cost tradeoffs associated with various residential energy efficiency 

and renewable energy technology options. 

Building Characteristics Considered in This Study. For the Prototype building, a two-story 

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. While complex floor plan geometries can be analyzed, a simple 

square floor plan was implemented for the purposes of the current analysis. The buildings were 

modeled with a slab-on-grade foundation type. Both buildings were assumed to have three 

bedrooms and two bathrooms. The both buildings had 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 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 use natural gas 

for the following end uses: cooking, water heating, and clothes drying. No options that would 

potentially reduce miscellaneous electric loads other than major appliances were included in the 

study. For the Phoenix example cases, air-conditioner capacities less than 1.5 tons were not 

considered nor were furnace capacities less than 50kBtu/hr. SEER10 air-conditioning equipment 

was included in this analysis for discussion purposes; however, after January 1, 2006, Federal 

minimum equipment efficiencies will mandate the use of SEER13 air conditioners. 

Occupancy/Operational Assumptions. Occupancy and operational assumptions are as defined 

in the Benchmark and include time-of-day profiles for occupancy, appliance and plug loads, 

lighting, domestic hot water use, ventilation, and thermostat settings. 

Base-Case Building. Results are calculated relative to the Benchmark, which defines baseline 

features. These features include wall, ceiling, and foundation insulation levels and framing 

factors; window areas; U-values and solar heat gain factors; interior shading; overhangs; air 

infiltration rates; duct characteristics; and heating, cooling, and domestic hot water system 

efficiencies. 

Cost Assumptions. Each option has an assumed first-cost and lifetime (Appendix B). Costs are 

retail and include national average estimated costs for hardware, installation labor, overhead, and 

profit. Some are input as unit costs that are then multiplied by a category constant (e.g., ceiling 

insulation costs are input per square foot and multiplied by ceiling area by BEopt). Some inputs 

are energy-option specific (e.g., cost of solar water heating systems). Inputs can also be based on 

total costs (e.g., cost of wall constructions with different insulation values) because BEopt will 

calculate the differences between option costs. 
81

Construction costs (wall insulation, ceiling insulation, foundation insulation, etc.) are typically 

based on R.S. Means51 cost estimates. Window and HVAC costs are based on quotes from 

manufacturers’ distributors. Appliance costs are based on manufacturers’ suggested retail prices. 

Building construction options (wall insulation, ceiling insulation, foundation insulation, 

windows, etc.) are assumed to have 30-year lifetimes. Equipment and appliance options 

typically have 10- or 15-year lifetimes. Lifetimes for lighting options (incandescent and compact 

fluorescent lamps) are modeled based on cumulative hours of use. 

Utility costs are assumed to escalate at the rate of inflation (i.e., to be constant in real terms). 

The mortgage interest rate is 5% above the rate of inflation. The onsite power option used for 

this study was a residential PV system with an installed cost of $7.50 per peak Watt DC, 

including present value of future operation and maintenance costs. This cost is assumed to be 

independent of PV system size. Additional costs associated with mounting large PV arrays were 

not considered. For Phoenix, natural gas is assumed to cost $0.7986/Therm, and the cost of 

electricity was modeled as $0.0778/kWh. 

Simulation Limitations. There are benefits that are not considered by the BEopt analysis 

method that will have an influence on the real-world design of a home, such as reduction in 

warrantee and liability exposure, increased customer satisfaction, and higher quality construction 

practices. The BEopt analysis method does not consider concerns with regard to indoor air 

quality, 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 energyefficient design approaches, the costs of moving a trade base to a different place, or termination 

of long-term relationships with a trade because the trade would not adopt energy-efficient 

practices. There is currently no methodology available to account for these effects in the 

simulation. Further development of a methodology to account for these effects and collection of 

appropriate data to inform the simulation would be necessary if there is interest in considering 

these effects. 

The BEopt analysis method is relatively new to the Building America program, the case studies 

included in the Building America Systems Research Results section were not initially simulated 

with BEopt nor was BEopt used to guide the design process of the case study homes included in 

the Building America Systems Research Results section. 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-scale or 

 

51 Residential Cost Data – 18th Annual Edition. 1999. Kingston, MA: R.S. Means, Company, Inc. 
82

custom-builde-scale, and 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 Phoenix TMY252 weather file. Figure 20 shows the 35% 

whole-house energy efficiency point that falls on the cost optimal curve for Phoenix. 

 52 Typical Meteorological Year weather data, http://rredc.nrel.gov/solar/old_data/nsrdb/tmy2/ 
83

Figure 20. The 35% point for a single-story Phoenix example case 
84

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 21 would 

represent a possible least-cost combination for 35% whole-house energy savings for a singlestory residence in Phoenix, Arizona. Because costs may vary significantly across the Hot-Dry 

/Mixed-Dry Climate region, from builder to builder, and over time, the above is only an example 

that may not reflect the actual least-cost set of options that would apply to a specific home, 

builder and location. 

At the high end of the whole-house energy-performance range considered here — 39% wholehouse energy savings — the total monthly cost is slightly lower than the 35% example. Figure 

21 shows an example combination that meets 39% whole-house energy savings compared to the 

35% combination.
85

Figure 21.53 Comparison of 39% point to 30% point, one-story Phoenix example cas

53 Note that costs shown in this figure are incremental relative to the 30% energy-savings point (shown in magenta) 
86

The comparison of the 35% combination (represented in magenta) to the 39% combination (blue 

only) shown in Figure 22 demonstrates that by using additional exterior wall insulation and a 

lower-SHGC, low-e glass, the 39% combination is less expensive in terms of total cost per 

month than the 35% single-story example. There are some savings associated with the 

downsizing of the cooling equipment as a result of the envelope improvements. 

Figures 22 and 23 look at the same points for the two-story case. 

The comparison of the 35% combination (represented in magenta) to the 39% combination (blue 

only) shown in Figure 23 demonstrates that by utilizing a SEER-14 air conditioner, the 39% 

combination is not only more efficient but costs less per month than the 35% two-story example. 

A more specific comparison of the features of the 35% and 39% examples are shown in Table 7 

for single- and two-story cases. 

Table 7 shows some differences in the options selected between the one- and two-story cases for 

the energy-savings levels and points selected. The differences between one- and two-story 

examples at the 35% and 39% energy-savings level are limited to exterior wall construction, 

glazing types, and air-conditioner SEER rating. 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. 
87

Figure 22. The 35% point for two-story Phoenix example case 
88

Figure 23.54 Comparison of 39% point to 35% point, two-story Phoenix example case

54 Note that costs shown are incremental relative to the 30% energy-savings point. 
89

Table 7. Comparison of Single- and Two-Story Example Cases 

CATEGORY 35% EXAMPLE 39% EXAM

Number of Floors One Story Two Stories One Story TwWalls R-11, 2x4, 16 in. oc R-19, 2x6, 24 in. oc R-19, 2x6, 24 in. oc R-Ceiling R-30 fiberglass R-30 fiberglass R-30 fiberglass R-Thermal Mass 1⁄2-in. ceiling drywall 1⁄2-in. ceiling drywall 1⁄2-in. ceiling drywall 1⁄2-Infiltration SLA = 0.0005 SLA = 0.0005 SLA = 0.0005 SLBasement Uninsulated Uninsulated Uninsulated UnGlass Type 

Two-pane, Low-e, U = 0.3, SHGC = 0.44 center of glass, insulated spacer, vinyl frame 

Two-pane clear, U = 0.49, SHGC = 0.76 center of glass, insulated spacer, vinyl frame 

Two-pane, Low-e, U = 0.29, SHGC = 0.29 center of glass, insulated spacer, vinyl frame 

Tw

SHins

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 

54

50

Refrigerator Standard: 671 kWh/yr 671 kWh/yr Standard - 671 kWh/yr 67Cooking Range 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Dishwasher 

Standard, 462 kWh, eight place-setting capacity, 131.6 kWh/yr machine energy, 5.39-gal/day DHW 

Standard, 462 kWh, eight place-setting capacity, 131.6 kWh/yr machine energy, 5.39-gal/day DHW 

Standard, 462 kWh, eightplace setting capacity, 

131.6 kWh/yr machine energy, 5.39-gal/day DHW 

Sta

setmaDH

Clothes Dryer Gas: 5.7 ft3, 2.75 EF, 70.1 kWh/yr, 31.8 therms/yr Gas: 5.7 ft3, 2.75 EF, 70.1 kWh/yr, 31.8 therms/yr Gas: 5.7 ft3, 2.75 EF, 70.1 kWh/yr, 31.8 therms/yr Ga

kW31

Clothes Washer 

Standard, 3.15 ft3, 533 kWh/yr, 

1.16 MEF, 65.6 kWh/yr machine energy, 4.63 gal/day DHW 

Standard, 3.15 cuft, 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 

Sta

53654.6

Lighting 14% CFL, 1574 kWh/yr Hardwired, 331 kWh/yr Plug in 14% CFL, 2534-kWh/yr Hardwired, 571 kWh/yr Plug in 14% CFL, 1574 kWh/yr Hardwired, 331 kWh/yr Plug in 14

Ha

Air Conditioner SEER 10, 2.5 Tons, 0.365 W/CFM AH Fan SEER 12, 4 Tons, 0.365-W/CFM AH Fan SEER 10, 2 Tons, 0.365W/CFM AH Fan SE

W/

Furnace 80% AFUE, 50 kBtu/hr 80% AFUE, 100 kBtu/hr 80% AFUE, 50 kBtu/hr 80Ducts 

Inside Conditioned Space, SA leakage = 1%, OA leakage = 0.23% of fan flow 

Inside Conditioned Space, SA leakage = 1%, OA leakage = 0.23% of fan flow

Inside Conditioned Space, SA 

leakage = 1%, OA leakage = 0.23% of fan flow 

Ins

lea0.2

Water Heater Gas Standard, 40 gallons, 0.55 EF, 0.76RE Gas Standard, 40 gallons, 0.55 EF, 0.76RE Gas Standard, 40 gallons, 0.55 EF, 0.76RE Ga

0.5
90

First-Cost Impacts 

For all of the 30% energy-savings level example cases, 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. To address first-cost 

concerns associated with energy-efficient home designs, some builders have implemented 

guaranteed energy-bill programs that may influence some potential homebuyers, such that they 

would be more willing to absorb the additional first cost into a 30-year mortgage knowing that 

their monthly cash flow will ultimately be reduced when the utility bill is considered. 

Builders who guarantee their homes are willing to tell buyers how much energy the home should 

use, and they guarantee these levels will not be exceeded. These guarantees are backed up with 

payments if limits are exceeded. Builders can work with insulation companies or other partners 

to offer guarantees or caps on their home’s energy costs, or they may develop their own 

programs. Some cover room comfort by guaranteeing that the temperature at the thermostat will 

not vary by more than 3 degrees at the center of any room served by that thermostat. A Building 

America team helped to develop these programs. 

Information on three of these programs can be found at: 

o Environments for Living – www.eflhome.com/index.jsp

o Engineered for Life – www.us-gf.com/engineered.asp

o The Energy Use and Comfort Guarantee –www.artistichomessw.com/guarantee.htm.”55

In some cases, homebuyers may be eligible for energy-efficient mortgages that allow potential 

home buyers to qualify for larger loans to compensate for additional first costs associated with 

energy-efficient options that are designed into a home. The Armory Park Del Sol in Tuscon, 

Arizona, case study featured later in this report is an example of a guaranteed energy bill 

program. 

The following features for energy-efficient loans are taken from Fannie Mae, the nation’s largest 

source of funding for mortgages. You can learn more about Fannie Mae at www.fanniemae.com. 

o Energy-efficient mortgages (EEM) are available for both purchase and refinance in 

conjunction with most Fannie Mae first-mortgage products, including conventional fixed-rate 

and adjustable-rate mortgages. 

o Monthly savings resulting from energy efficiency can be used to qualify borrowers for a 

larger mortgage. This means consumers can buy more home in the form of energy efficiency 

or other upgrades. 

o The EEM can be used with many Fannie Mae mortgage products. The guidelines of the 

selected Fannie Mae mortgage apply, with the EEM allowing for the projected energy 

 

55 Building America Best Practices Volume 2, Builders and Buyers Handbook for Improving New Home Efficiency, 

Comfort, and Durability in the Hot-Dry and Mixed Dry Climates, September 2005, NREL/TP-550-36360, Page 

HOM-5. 
91

savings to provide an adjustment to the loan-to-value and qualifying ratios that favor the 

borrower.”56

Table 8 shows that the first cost associated with the 39% example case are larger than the first 

cost associated with the 35% example case. The first-cost increase (relative to the 35% example) 

is a result of the use of a SEER-14 air conditioner. At a 7% mortgage interest rate, an additional 

$1,738 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 consumer costs in the Phoenix area or other HotDry/Mixed-Dry climate areas. The actual first costs for a particular builder and potential 

homeowner in the Hot-dry/Mixed-dry climate area may vary substantially from Table 8. 

Variations in costs would affect the outcome of the optimization. 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 and in the First Costs, Cost Tradeoffs, and Owner Annualized 

PITI + Energy section. 

Key Cost Tradeoffs 

The analysis for a single- and two-story home in the Phoenix climate shows that the main trends 

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

improved exterior wall constructions, ducts in conditioned space, and higher efficiency air 

conditioners. The results indicate that the main driver for energy and cost savings in the Phoenix 

climate are cooling load reduction strategies (better wall insulation, low-e glazing, and ducts in 

conditioned space) coupled with higher SEER air conditioners to reduce cooling energy use. 

One of the tradeoffs shown in most of the example cases is that the improved envelope allows 

for a smaller-capacity furnace to be installed, which offsets the first-cost. 

Table 8. Incremental First Cost for the Two-Story Phoenix Example Cases 

 PHOENIX, TWO-STORY 

Category Incremental First-Cost 35% Example Incremental First-Cost 39% Example 

Walls $317.00 $317.00 

Air Conditioner $303.00 $607.00 

Furnace -$146.00 -$146.00 

Ducts $960.00 $960.00 

Total $1,434.00 $1,738.00 

 

56 Building America Best Practices Volume 2, Builders and Buyers Handbook for Improving New Home Efficiency, 

Comfort, and Durability in the Hot-Dry and Mixed Dry Climates, September 2005, NREL/TP-550-36360, Page 

HOM-4. 
92

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 Hot-Dry and Mixed-Dry 

Climates can be built on a cost-neutral basis by production builders. Table 9A shows a summary 

for energy-related features for the case studies included in the following section of this report 

and examples of results from use of the BEopt analysis method for Hot-Dry and Mixed-Dry 

Climates. 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 

Hot-Dry and Mixed-Dry 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 and the case studies are the 

result of 3 years of field experience and design work done by Building America’s research 

teams. 
93 

Table 9A. Summary of Energy Features for Case Studies and BEopt Results 

Case Studies BE

Category 

Merlin 

Contracting 

New American 

Home 

JWM 

Armory Park 

Del Sol 

Artistic Homes 

Gamlen 

Residence 

Premier 

Homes 

Premier 

Gardens 

Morrison 

Homes 

Lakeside 

Centex 

Windemere 

Adventura/ 

Lunaria 

35% point Neighb

4 

Floor Area Not Described 1916 2700 1503 2126-3672 2250-3800 1500 1500 

# of Floors 3 1 1 1 1-2 2 1 1 

Number of Bedrooms 4 2 4 3 4 Not Described 3 3 

Number of Bathrooms 4 2 3 2 3 Not Described 2 2 

Walls 

Insulated 

Concrete Forms, 

10-in. concrete 

with 2-5/8-in. XPS 

each side, R22 

8-in. CMU, 

R-12 exterior 

rigid foam 

2x6 24 in. oc, 

R23 cellulose + 

R-1.2 asphalt 

impregnated 

sheathing 

2x4, R-13 Batt 

+ 1-in. EPS 

sheathing 

R-19 

2x4 16-in. oc,

R-15 blown-in 

fiberglass 

R-11, 2x4, 

16-in. oc 

R-13, 2

16-in. 

Ceiling SIP, 8-1/4-in. thick, R-30 

R-38 fiberglass 

batt/I joists, 

flat roof 

R-38 loose fill 

fiberglass R-38 

R-30 (twostory) / R-38 

(1 Story) 

R-48 blown in 

fiberglass 

R-30 

fiberglass

R-30 

fibergla

Thermal Mass 

ICF exterior walls 

and ICF basement 

walls 

8-in. CMU Not Described Not Described Not Described Not Described 1⁄2-in. Ceiling Drywall 

Two 5/8

Ceilin

Drywa

Layer

Infiltration 

Sealing at SIP to 

ICF joints, roof 

penetrations and 

all gaps 

2.9 ACH50 2.5 in2 per 100 ft2 of envelope 3.5 SLA Not Described 3.9 SLA SLA = 0.0005 SLA 

0.000
94 

Table 9A (continued). Summary of Energy Features for Case Studies and BEopt Resu

Case Studies BEo

Category 

Merlin 

Contracting 

New American 

Home 

JWM 

Armory Park 

Del Sol 

Artistic Homes 

Gamlen 

Residence 

Premier 

Homes 

Premier 

Gardens 

Morrison 

Homes 

Lakeside 

Centex 

Windemere 

Adventura/ 

Lunaria 

35% point Neighbor 

Basement/Slab/ Crawlspace 

Basement - 

Insulated Concrete 

Forms, 10-in. 

concrete with 2-

5/8-in. XPS each 

side + waterproof 

coating and 

membrane, R-22 

Slab = R-12 

slab edge 

insulation 

Conditioned 

Crawlspace = 

R-14, 2-in. 

Polyisocyanurate 

Rigid Insulation 

Slab Slab Slab Uninsulated Uninsulate

Glass Type 

Low-e, 

U = 0.36, 

SHGC = 0.35 

Eight French 

Doors, 

U = 0.38, 

SHGC = 0.21, 

45 ft2 of single 

glazing, 

U = 1.11, 

SHGC = 0.86 

Low-e, 

U = 0.32, 

SHGC = 0.30 

Double-glazed 

Low-E2 vinyl frame, 

U = 0.35, 

SHGC = 0.35 

Slider: 

U = 0.36, 

SHGC = 0.30 

Single Hung: 

U = 0.33, 

SHGC = 0.32 

Fixed: 

U = 0.30, 

SHGC = 0.33 

Sliding Patio 

Door: 

U = 0.34, 

SHGC = 0.30 

French Door: 

U = 0.33, 

SHGC = 0.28 

Spectrally 

Selective 

U = 0.36 

sliders, 

0.33 fixed, 

0.354 patio 

door, 

SHGC = 0.33 

sliders, 

0.36 fixed, 

0.35 patio 

door 

Low-E2 Vinyl,

U = 0.35, 

SHGC = 0.37 

2 pane Low-e,

U = 0.3, 

SHGC = 0.44

Center of 

Glass, 

insulated 

spacer, Vinyl 

frame 

2 pane Low

U = 0.32, 

SHGC = 0.6

Center of 

Glass, 

insulated 

spacer, Vin

frame 

Window Area per Wall Not Described Not Described Not Described Not Described Not Described Not Described 

270 ft2, 

12.5% N&S, 

50% W, 

25% E 

270 ft2, 

12.5% N&S

50% W, 

25%E 
95 

Table 9A (continued). Summary of Energy Features for Case Studies and BEopt Resu

Case Studies BEopt 

Category 

Merlin 

Contracting 

New American 

Home 

JWM 

Armory Park Del Sol 

Artistic 

Homes 

Gamlen 

Residence 

Premier 

Homes 

Premier 

Gardens 

Morrison 

Homes 

Lakeside 

Centex 

Windemere 

Adventura/ 

Lunaria 

35% point Neighbor 4 

Refrigerator Not Described ENERGY STAR Not Described Not Described 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 45 Therms/yr 45 Therms/yr 

Dishwasher Not Described ENERGY STAR Not Described Not Described ENERGY STAR Not Described 

Standard, 

462 kWh, 

eight place 

setting 

capacity, 

131.6 kWh/yr 

machine 

energy, 

5.39-gal/day 

DHW 

Standard, 

462 kWh, eight 

place setting 

capacity, 

131.6 kWh/yr 

machine 

energy, 

5.39-gal/day 

DHW 

Clothes Dryer Not Described Not Described Not Described Gas Dryer stub Not Described Not Described 

Gas - 5.7 ft3, 

2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 

70.1 kWh/yr, 

31.8 therms/yr 

Clothes Washer Not Described Not Described Not Described Not Described ENERGY STAR Not Described 

Standard, 

3.15 ft3, 

533 kWh/yr, 

1.16 MEF, 

65.6 kWh/yr 

machine energy, 

4.63-gal/day 

DHW 

Standard, 

3.15 ft3, 

533 kWh/yr, 

1.16 MEF, 65.6 

kWh/yr machine 

energy, 4.63-

gal/day DHW 
96 

Table 9A (continued). Summary of Energy Features for Case Studies and BEopt Resu

Case Studies BEo

Category 

Merlin 

Contracting 

New American 

Home 

JWM 

Armory Park Del Sol 

Artistic Homes 

Gamlen 

Residence 

Premier Homes 

Premier 

Gardens 

Morrison 

Homes 

Lakeside 

Centex 

Windemere 

Adventura/ 

Lunaria 

35% point Neighbor 4 

Lighting Not Described Incandescent / flourescent Not Described 100% fluorescent 100% fluorescent

CFLs on all 

permanent 

fixtures 

except dining 

chandelier 

14% CFL, 

1574 kWh/yr 

Hardwired, 

331 kWh/yr 

Plug in 

14% CFL, 

1574 kWh/y

Hardwired, 33

kWh/yr Plug 

Cooling 

Four systems, 

SEER 16 Heat 

Pump, SEER 

14.8, 15.9, and 

15 condensing 

units, Total of 18 

tons 

SEER 12 heat pump SEER 13 SEER14 w/ TXV SEER14 SEER10 

SEER 10, 

2.5 Tons, 

0.365 W/CFM 

AH Fan 

SEER 10, 

3 Tons, 

0.365 W/CFM 

AH Fan 

Heating 

One heat pump, 

COP = 3.6 @ 

47°F, 

Two 94% AFUE 

furnaces w/ twospeed air 

handlers, One 

94% AFUE 

furnace with twozone control 

dampers 

8.6 HSPF heat pump 

Combo System - 

90%CAAFUE in 

conditioned space

91% AFUE 92% AFUE

80% AFUE, 

variablespeed AH fan 80% AFUE, 50 kBtu/hr 80% AFUE

75 kBtu/hr 

Ducts 

Inside conditioned 

space with UL181 

mastic sealed 

joints 

15 CFM Total Leakage 

@ 25Pa, in conditioned 

space 

Sheet metal and 

flex duct in crawl 

space, 5% or less 

to outside 

R-4.2 ducts 

insulation buried in 

attic ~ R-13 

equivalent 

R-6 

R-4.2 flex 

ducts buried 

in R-48 attic 

insulation 

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 
97 

Table 9A (continued). Summary of Energy Features for Case Studies and BEopt Resu

Case Studies BEop

Category 

Merlin 

Contracting 

New 

American 

Home 

JWM 

Armory Park Del Sol 

Artistic Homes 

Gamlen 

Residence 

Premier Homes 

Premier 

Gardens 

Morrison 

Homes 

Lakeside 

Centex 

Windemere 

Adventura/ 

Lunaria 

35% point Neighbor 4 

Water 

Heater 

75-gallon power 

vented, 

55 MBH input, 

0.50 EF 

Batch Solar Water 

Heater with Tankless 

backup 

Combo System - 

0.86 CAEF, 

34 gal in garage 

Tankless 0.82 EF, 

R4 insulation on 

trunk lines 

Tankless 

0.82 EF + 

pipe 

insulation 

Tankless 

0.82 EF, 

PEX home 

run piping 

Gas Standard, 

40 gallons, 

0.55 EF, 

0.76 RE 

Gas Standa

40 gallons

0.55 EF, 

0.76 RE 

On-site 

Power 

system 

1.5-kW grid-tied PV 

system 

2.4-kW DC system, 

building integrated

2-kW roof 

integrated 

PV tiles 

Optional 

Space 

Heating 77% 69% 47% 50% 44% 37%/19% 48% 65% 

Space 

Cooling 50% 62% 55% 76% 78% 20%/43% 53% 48% 

DHW - 7% 0% 33% 43% 37% 54%/58% 11% 12% 

Lighting 0% 25% 0% 74% 50% 67%/67% 0% 0% 

Appliances + 

MEL 0% 1% 0% 3% 1% 0%/0% 6% 6% 

Total 

Energy 

Use 

31% 37% 29% 39% 36% 30%/33% 35.6% 33.8% 
98 

Table 9B is a summary of the case studies presented in this report. Figure 24 shows the location 

of the case studies presented in this report. Locations are indicated with stars. 

Table 9B. Summary of Source Energy Savings by End-use as a Percentage of Total 

Energy Use for the Seven Hot-Dry/Mixed-Dry Case Studies 

Percent Source Energy Savings 

 Centex – Windemere

End Use 

Merlin 

Contracting 

 New 

American 

Home 

JWM 

 Armory 

Park Del 

Sol 

Artistic 

Homes 

 Gamlen 

Residence 

Premier 

Homes 

 Premier 

Gardens 

Morrison 

Homes 

 Lakeside 

Adventura Lunaria 

Space Heating 77% 69% 47% 50% 44% 37% 19% 

Space Cooling 50% 62% 55% 76% 78% 20% 43% 

DHW -7% 0% 33% 43% 37% 54% 58% 

Lighting 0% 25% 0% 74% 50% 67% 67% 

Appliances + MEL 0% 1% 0% 2.5% 1% 0% 0% 

Total Energy Use 31% 37% 29% 39% 36% 30% 33% 

Number of Homes 1 6 1 

71 

complete, 

475 total 

buildout 

1 complete, 

120 total 

buildout 

6 19 
99 

Figure 24. Location of 30% Hot-Dry and Mixed-Dry Climate case studies 
100 

House Case Studies 

Development: Sahara Lake 

Builder: Merlin Contracting 

Location: Las Vegas, Nevada 

Within a high-pressure situation, the builders who construct The New American Home® 

(TNAH®) each year face unique obstacles: a frustratingly short and tight timeframe, designers 

and manufacturers they may have never worked with, products and practices they may be 

unfamiliar with, and materials that may not get specified right. On top of all this, The National 

Association of Home Builders (NAHB) requires that TNAH’s builders construct houses to 

extremely high performance requirements, which adds its own set of challenges. 

TNAH® is an annual showcase project co-sponsored by the NAHB’s National Council of the 

Housing Industry and Builder Magazine. The NAHB began requiring that each home, beginning 

with TNAH® 2001, be built to extremely high energy-efficiency goals and other highperformance targets because they know it’s important in the industry. IBACOS, through the 

Department of Energy’s Building America program, has worked with the builders in the design 

and construction to ensure that each home meets specific performance goals. 

Merlin Contracting built TNAH® 2004 in the Sahara Lake community, just west of downtown 

Las Vegas. TNAH® 2004 was designed to reach a Home Energy Rating System (HERS) score 

of 90, a score well above the current ENERGY STAR® rating requirement of 86, and uses a 

number of high-performance technologies. 

The rear elevation of the pilot home is the most dramatic face because it is looking over the lake 

and highlights the glazing for the high-ceiling living room. The rear of the house faces south. 

Figures 25 and 26 are floor plans for this house at Sahara Lake in Las Vegas, Nevada (Figure 27) 
101 

1st Floor 

2nd Floor 

Figure 25. Merlin Contracting house floor plan, 1st and 2nd floor 
102 

Figure 26. Merlin Contracting house floor plan, 3rd floor

Figure 27. The New American Home at Sahara Lake, Nevada
103 

House Specifications 

The house is located on a lot on Sahara Lake, an exclusive community about 6 miles west of 

downtown Las Vegas. The 5,180-ft2 home features a loft design that offers greater versatility for 

interior design and layout options. 

As-Built Specifications 

• Picture windows are from Loewen and are aluminum-clad, wood-framed, double-glazed, 

with a spectrally selective low-emissivity coating, U-value of 0.36, SHGC of 0.35. Eight sets 

of French doors, with U-values of 0.38 and SHGC of 0.21, were installed. The master shower 

has approximately 45 ft2 ofsingle glazing. A U-value of 1.11 and SHGC of 0.86 is assumed 

for these windows (Carmody 1996). 

• Second-floor fenestration is shaded externally by 9-in. by 2-in. copper-clad wooden 

sunshades. External, operable, and electronically controlled shading covers first-floor westside fenestration. 

• All exterior walls above grade consisted of insulated concrete forms (ICF). The ICF system 

includes a 10-in. concrete core sandwiched by two 2-5⁄8-in. layers of extruded polystyrene 

(EPS) to give a thermal resistance of R-22 (Figures 28 and 29) 

• Basement walls consisted of the ICF system covered by a waterproof coating and membrane 

(Figure 30) 

• To improve building airtightness, a great deal of emphasis was placed on sealing the 

numerous penetrations through the building enclosure and any gaps at the roof-wall 

connection. 

• Structural panels made up of an expanded polystyrene core bonded between two layers of 

OSB were used as the roof deck. Panels were 8-1⁄4 in. thick and provided R-30 thermal 

performance (Figure 31). 

Mechanical Equipment 

• A total of four Lennox HVAC systems were installed to handle the five zones in the house; 

the second-floor system has a mechanical damper-zone control system. Three direct-vent 

natural-gas furnaces and a heat pump will be used for space heating, and each has a variablespeed blower. The three air handlers have a minimum 94% AFUE, and all of them are 

located in conditioned space. The condensing units provide two-stage operation and have 

efficiencies of SEER 14.8, 15, and 15.9. The heat pump has two speeds, is located in 

conditioned space, and has a COP rating of 3.6 at 47°F and 16 SEER. 

• A 75-gallon power-vented domestic water heater, 55 MBH input, with an assumed EF of 

0.50, was used because manufacturer’s data was unavailable. Also included was an 

electronically controlled pump-and-valve assembly that provides rapid delivery of hot water 

to plumbing fixtures without the loss of cold water down the drain. 

• All ductwork, which consists of flex and spiral galvanized metal, is within the conditioned 

space of the home. Ductwork was sealed with UL-181 approved water-based mastic sealant 

or appropriate caulking. 
104 

• A heat-recovery ventilator (HRV) provides mechanical ventilation on a balanced basis to 

first-floor HVAC systems. 

Figure 28. Steel beams were used for structural framing and 

are anchored into the insulated concrete form wall. 

Figure 29. Insulated concrete forms make up 

the exterior shell of the home. 
105 

Figure 30. Insulated concrete forms were used to form the 

walls of the basement 

Figure 31. Structural insulated panels provide the air 

and thermal barrier for the roof 
106 

Innovations 

Specific technologies used in TNAH® 2004 include a foundation system and above-ground 

exterior walls of insulated concrete forms; windows that limit solar heat gain; a roof system built 

with structural insulated panels; a heat-recovery ventilator for the ventilation system; and 

superior efficiency condensing units. The insulated concrete forms provide excellent insulation 

for the basement. Structural insulated panels provide the roof system with good insulation and 

airtightness characteristics. The heat-recovery ventilator ensures good indoor air quality in an 

efficient manner by tempering incoming hot outdoor air with cooler indoor air. The condensing 

units have a seasonal energy efficiency ratio (SEER) between 14.7 and 16 and provide excellent 

cooling capacity while using minimal energy. 

As a result of these improvements and advanced technologies, the home will use 46% less 

energy for space heating and cooling, hot water, and lighting than the typical Las Vegas new 

home. 

The Bottom Line 

Through this project, builders get a unique opportunity to learn new ways to build quality homes, 

without worrying about the costs involved with a learning curve. This is something very valuable 

to Merlin Contracting, the builder of TNAH® 2004. As a custom homebuilder, their own bottom 

line doesn’t matter as much as their customer’s bottom line. “It’s important for us to use their 

customer’s money as wisely as possible,” says Bart Jones, a principal in Merlin Contracting. 

With their customer’s bottom line in mind, they can’t gamble on products or practices they’re not 

familiar with. Knowing that something they tried through the TNAH® project works—or 

doesn’t—eliminates guesswork and enables them to confidently make cost-effective 

recommendations to their customers. For example, based on their experience using Insulated 

Concrete Forms (ICFs) in TNAH® 2204, Merlin would recommend ICFs to their customers. “In 

fact, recently we did recommend that one client use ICFs for the wall system and are currently 

building his 20,000-ft2

 “French Country Cottage-style Compound” in Las Vegas using ICFs . 

This is something we wouldn’t have done before because we’d never used it,” said Bart Jones. 

The NAHB’s commitment to quality challenges builders to push the envelope further in the 

already high-pressure situation of building TNAH®. With the help of the DOE’s Building 

America Program, builders are successfully meeting the challenge and learning valuable lessons 

in the process. The builders, and the industry as a whole, are seeing that the value added to their 

business—reduced warranty and callback expenses, reduced liability risk, and increased 

customer satisfaction—is worth the effort. 
107 

Key Features 

• Low-emissivity solar-control windows 

• Foundation and above-grade walls of insulated concrete forms that provide airtightness and 

R-22 thermal performance 

• All air-handling equipment within conditioned space 

• High-efficiency furnaces (minimum 94% AFUE) and condensing units (between 14.7 and 16 

SEER) 

• One heat pump with coefficient of performance (COP) of 3.6 and 16 SEER 

• Heat-recovery ventilator delivers fresh air to return plenum 

• Air-distribution system leakage to the outside target is 3% of system airflow or 216 cfm at 25 

Pa. 

Advanced Systems and Construction Methods 

The builder was interested in the home at least reaching the ENERGY STAR® level of energy 

efficiency. In order to meet Building America objectives, IBACOS proceeded to design the 

home to achieve, at a minimum, a HERS 90 level. This level of energy efficiency matches that of 

the last three New American Homes®. The design featured several advanced systems including 

improved building enclosure insulation, enhanced building airtightness, higher-performance 

windows, external shading devices, high-efficiency heating and cooling equipment, and 

mechanical ventilation. Optimized HVAC and energy-efficient lighting strategies were 

recommended. The reasons behind each not being implemented are also discussed. 

Construction Challenges 

Building Enclosure Insulation 

A 15-in.-wide ICF system, including 10-in.-wide concrete core and a thermal resistance value of 

R-22, was chosen as the structural and insulating system for the exterior walls and basement. 

Figure 28 and Figure 29 show the ICF systems under construction. The builder made this choice 

after a presentation by the Portland Cement Association on the system’s merits, namely reduced 

construction time and increased durability, airtightness, and thermal performance over framedwall systems. The mass of the ICF wall will also have an effect the impact of solar radiation. We 

suspect that this will result in a more gradual distribution of heat through the wall assembly, 

thereby lowering cooling load peaks and allowing for a more-uniform distribution of heat gain. 

At first, the builder was considering using a poured-concrete foundation system insulated on the 

exterior with a rigid or semi-rigid insulation board to a minimum level of R-10. After an 

examination of the connection details that would be required at the top of the foundation wall 

with the ICF system, the logistics of having another subcontractor and the aforementioned 

benefits of ICFs, the builder choose to use the ICF system as the only structural system for the 

home. 
108 

Structural insulated panels (SIPS) made up of an EPS core bonded between two layers of OSB 

were used as the roof deck (Figure 30). Panels are 8.25 in. thick and provide R-30 thermal 

performance. The panels were placed within a structural steel skeleton and then fastened to the 

steel. The roofing material used is copper. The copper roofing was placed over two layers of 7/8-

in.-thick plywood, which sat directly on the panels. We recommended that the roofing sit on 

battens, thereby allowing for the creation of an air space, which would limit heat gain to the 

roofing panels, limit the temperature of the copper, and allow the roofing and the panel to cool 

during cooler periods. 

Building Enclosure Air-tightness 

A great deal of emphasis was placed on sealing gaps in the building enclosure and the 

connections between the different components. The most prominent connection point between 

component systems was at the SIPS roof to ICF wall intersection. The air tightness of the roof 

system was also considered. The numerous penetrations through the building enclosure were 

sealed as well. 

Recommendations on Building Enclosure. The site superintendent for the pilot home believed 

that construction time savings could be realized when using insulated concrete forms, especially 

if the house is designed structurally from the start based on this system. He noted that the less the 

design is architecturally complicated, the faster the installation of the ICF system. The 

EnergyGauge software estimated that the mass effect alone of the ICF system has a noticeable 

reduction in energy consumption, particularly the amount of energy in therms used for heating. 

The use of SIPS was also well received because of its quick installation. Merlin may use this 

product again in vaulted-ceiling applications. Turning an attic into semi-conditioned space 

creates a haven for air handlers and ductwork away from the extremely hot temperatures 

associated with a vented attic. Leaky return-system ductwork in the attic no longer draws very 

hot air in the summer, which raises the temperature of air being delivered to the home. The 

result is that the air handler has to work longer for the setpoint temperature to be reached. 

Therefore, even where roof plans do not call for a vaulted or cathedralized ceiling, SIPS for the 

roof are recommended to create a conditioned space in the attic. 

Because many of the homes Merlin builds sell for more than a million dollars and cost hundred 

of thousands of dollars to construct, they can more easily absorb any additional costs associated 

with advanced-building enclosure systems, such as ICF or SIPS. The energy-efficiency value of 

building-enclosure improvements, as presented in Tables 10 and 11, was the second highest of 

all improvements. 

High-Performance Windows 

Aluminum-clad, wood-framed windows with double glazing and a spectrally selective lowemissivity coating and U-values of 0.36 and SHGC of 0.35 were used for the project. The low U 

and SHGC values of these windows will result in reduced cooling and heating loads compared to 

the builders’ standard window, which have U-values of 0.47 and SHGC of 0.50. Eight sets of 

French doors with U values of 0.38 and SHGCs of 0.21 were installed. Approximately 45 ft2

 of 

single glazing, with 25 ft2

 facing south and the rest facing west, exists in the second-floor master 

shower. A U-value of 1.11 and SHGC of 0.86 is assumed for these windows. Privacy control is 

an issue for the master shower. 
109 

Table 10. Summary of Predicted End-use Site Energy for Merlin Contracting Project 

Building America 

Benchmark 

Builder Standard 

Home 

Pilot Home 

As Built 

End-Use KWh therms KWh Therms KWh Therms

Space 

Heating 

451 638 518 730 87 144 

Space 

Cooling 12,114 19,556 6,075 

DHW 139 139 150 

Lighting 4,599 4,599 4,599 

Subtotal 17,164 777 24,673 869 10,761 294 

Equipment 669 150 669 150 669 150 

Miscellaneous 8,962 8,962 8,962 

Total 26,795 927 34,304 1,019 20,392 444 
110 

Table 11. Summary of Estimated End-use Source Energy 

Estimated Source Energy Savings 

Annual Source Energy 

% of End Use % of Total 

End-Use BA 

Benchmark 

(MBTU) 

Builder 

Standard 

(MBTU) 

Pilot 

Home 

(MBTU) 

BA 

Benchmark 

Builder 

Standard 

BA 

Benchmark 

Builder 

Standard 

Space Heating 70 80 16 77% 80% 14% 13% 

Space Cooling 131 211 65 50% 69% 17% 31% 

DHW 14 14 15 -7% -7% 0% 0% 

Lighting 50 50 50 0% 0% 0% 0% 

Subtotal 265 355 146 45% 79% 31% 44% 

Equipment 23 23 23 0% 0% 0% 0% 

Miscellaneous 97 97 97 0% 0% 0% 0% 

Total 385 475 266 31% 44% 31% 44% 
111 

Recommendation. In the hot climate of Las Vegas, the energy savings are obvious when using 

windows that have a low-emissivity coating compared to those that do not. Merlin should 

consider using these windows on all their homes and can sell the added benefit that upholstery 

fabrics are less likely to fade and that the temperature in the home will be more uniform from 

room to room. Upgrading to these windows will mean an additional cost, but the load reduction 

from the windows is key to optimizing the entire HVAC system and, thereby, reducing overall 

construction costs and increasing system efficiency. Window performance values of U = 0.35 

and SHGC = 0.35, or better, are recommended for Las Vegas. 

External Shading 

Second-floor areas with fenestration are shaded externally by 9-in. by 2-in. copper-clad wooden 

sunshades. The roofing system was designed by the architect to extend over most of second-floor 

outdoor decks, thereby providing relief from the summer sun. On the west side of the first floor, 

externally mounted shade covers can roll down in front of glazing from its soffit location. The 

covers can be controlled to roll down as far as necessary to prevent solar heat gain. Internal 

shade covers are in place on south- and west-facing glazing. 

HVAC Equipment Efficiencies 

Four pieces of high-efficiency equipment serve the house through five zones, all situated within 

conditioned space. An air-source heat pump with a COP 3.6 at 47°F and 16 SEER serves the 

basement, which includes two bedrooms. A heat pump was selected for this zone in order to 

highlight Lennox’s new system. Two two-speed air handlers with 94% AFUE and 14.8 and 15.9 

SEER condensing units serve the first floor, with one unit dedicated only for the living room. For 

these units, an airtight mechanical room was built. Lastly, one air handler with 94% AFUE and 

15 SEER and two zone-control dampers serve the second floor. 

Recommendations. Merlin gained experience with using high-efficiency furnaces and 

condensing units in the pilot home. According to the builder’s HVAC subcontractor, to upgrade 

to a high-efficiency 93% AFUE furnace costs about $400 more. To upgrade to a high-efficiency 

16 SEER condensing unit from a 12 SEER unit costs about four times more – a significant price 

increase. Clearly, such a pricing structure by condensing unit manufacturers creates an obstacle 

to the use of 16 SEER equipment. Another reason Merlin does not use higher efficiency HVAC 

equipment is that their clientele are wealthy and are not usually concerned about spending less in 

utility costs. In any case, we recommend that subcontractors use higher efficiency HVAC 

equipment, 93% AFUE furnaces and 14 SEER condensing units. 

Air Distribution 

All ductwork in the home is inside the conditioned enclosure. In addition, to improve HVAC 

system airtightness, UL 181-approved mastic sealant was applied on all joints between all pieces 

of ductwork, as well as joints in the furnace and joints between ductwork and the furnace. 

Caulking material, specifically for galvanized ducts, was used on the joints in the second-floor 

air-distribution system. This approach was specifically used because of the exposed nature of the 

ductwork and the more presentable finish provided by the caulking-over-mastic sealant. 
112 

A detailed duct layout based on calculated loads and predicted air movement was developed to 

ensure that correctly sized ductwork could efficiently move air from the three air handlers and 

the heat pump. The builder chose instead to use the design from a local HVAC engineering firm 

that they use for all of their HVAC design services. 

Mechanical Ventilation 

The builder installed a heat recovery ventilator (HRV) to provide a balanced source of 

mechanical ventilation. The ventilator delivers air to the return plenum of the two first-floor air 

handlers. Our initial recommendation was to have an HRV installed on each floor. According to 

manufacturers’ specification, the unit will deliver a total of 200 cfm of outdoor air on a 

continuous basis. 

Recommendations. As Merlin increases the airtightness of their homes, mechanical ventilation 

will be needed. By explaining the benefits of such a system to enhancing indoor air quality, this 

need has become apparent to Merlin. The heat-recovery ventilator is a good choice for the Las 

Vegas climate, and we recommend that Merlin use them in future homes. 

HVAC Optimization 

An engineered HVAC system design was developed for the pilot home by IBACOS. The design 

determined that with the use of spectrally selective high-performance windows, good thermal 

performance in the foundation walls, exterior walls and roof, and an airtight building enclosure, 

the HVAC equipment did not need to have the capacity suggested by a conventional design 

based on ACCA Manual J (1992) calculations performed by the local HVAC engineering firm. 

The conventional design estimated that 18 tons of cooling capacity would be needed for the 

home, while our final design estimated that 13.5 tons would be sufficient. In addition, our design 

is based on a 70oF setpoint temperature used for cooling system design as requested by the 

builder and a lighting load of 2 watts per square foot of floor area, which is reflective of show 

home conditions in Las Vegas based on information obtained from a lighting survey conducted 

at TNAH® 2003. In addition, our design was based on smaller airflows occurring over a longer 

period of time and, thereby, minimized the start-up frequency of HVAC equipment and allowed 

units to reach the best operating efficiency. 

In an effort to use the equipment we specified while still using the conventional design for the air 

distribution system, we recommended a plan to the local HVAC engineering firm to make some 

of the registers temporarily inactive and, thereby, reduce airflow to the particular room. The plan 

would allow for equipment change-outs to occur if larger capacity units were necessary, while 

allowing for the use of the conventional air-distribution system design. This plan was rejected as 

being too complicated and hard to implement. 

The builder indicated that over-sizing of cooling equipment capacity was standard practice for 

their homes because it ensured that homeowners could always be adequately cooled. Apparently 

custom home purchasers are sometimes inclined to set temperatures very low in the summer, as 

low as 63°F. In the end, the builder choose to follow the complete conventional design approach, 

because it had a track record of keeping customers satisfied and was guaranteed in their eyes by 

the local HVAC engineering firm, even though it was stressed to them to have excessive capacity 

would be inefficient. If any of Merlin’s customers had comfort complaints in their homes, the 

local HVAC engineering firm would do what was necessary, including replacing equipment, to 
113 

ensure the customer was satisfied. As the project neared completion, the builder had misgivings 

regarding not following our design approach, having had adequate time to consider the benefits 

of an optimized HVAC system design. 

With respect to air distribution, our analysis determined that if the conventional design was 

followed, air movement would be noticeable by the occupants, and they would possibly 

experience discomfort as a result of drafts and frequent start-ups. For example, in the living room 

we recommended that 805 cfm of air be delivered, while the conventional design specified 1600 

cfm. 

Recommendation. According to heating and cooling load calculations, which took into account 

the improved thermal performance of the home through higher-performance windows, increased 

building airtightness and improved thermal enclosure, it was determined that 13.5 tons of cooling 

capacity could adequately condition the home. Instead of following our design, Merlin chose to 

follow the conventional design offered by their HVAC engineer and installed 18 tons of cooling 

equipment. Long-term monitoring equipment is being used to evaluate if temperature and 

humidity conditions are being maintained at a comfortable level. We expect that the frequency of 

HVAC equipment start-ups will be noticeable and that anecdotes from homeowners will reflect 

drafty and possible uncomfortable conditions in several rooms. We plan on sharing this 

monitoring information with Merlin and their HVAC engineer in an attempt to get them to 

optimize their HVAC design in future homes. 

Energy-Efficient Lighting 

IBACOS, in conjunction with a lighting designer from the General Electric Lighting Center, 

developed an energy-efficient lighting design for consideration by the architect. The design 

highlighted the use of compact fluorescent lamps and lighting distribution that improved the 

quality of lighting in each room. But, because of the showcasing aspects for this home, the 

architect opted to only work with a lighting manufacturer and their designers on the lighting 

design and the fixture and lamp selection. Consequently, many fixtures were selected for their 

aesthetic appeal only rather than considering their energy use and lamp longevity. 

Recommendations. The houses built by Merlin contain many lighting fixtures. To reduce peak 

cooling loads and reduce energy use, we recommend that they use energy-efficient lighting 

where possible. The recommendations made in the energy-efficient lighting design developed for 

the pilot home should be followed in future projects. 

The analysis determined that the pilot home as built will save 45% with respect to the 

Benchmark and 79% with respect to the Builder Standard Home for end-use source energy 

related to space heating, space cooling, domestic hot water production, and lighting. Total 

savings are 31% with respect to the Benchmark and 44% with respect to the Builder Standard 

Home. The total savings values reflect the fact that lighting and appliance energy use was 

constant between the three comparison homes. 
114 

Development: Armory Park del Sol 

Builder: John Wesley Miller Companies 

Location: Tucson, Arizona 

Figure 32. Floor plan (left) of Amory Park del Sol (right) 

An Award-Winning Community 

As the 2005 EnergyValue Housing Award Builder of the Year, John Wesley Miller (JWM) 

Companies’ mission is energy efficiency. John Wesley Miller Said, “Our mission is to design 

and build the most energy efficient development in the world by incorporating the latest energy 

saving technologies...in all of the homes we build.” The Armory Park del Sol development 

(Figure 32) in downtown Tucson combines desert-climate appropriate designs with roof solar 

energy production to win Sonoran Institute’s Livable Community Award (2005), SAHBA 

Builder of the Year (2003), and City of Tucson’s Most Energy Efficient Builder (2003). 
115 

 Table 12. Energy Simulation of John Wesley MIller Compared to Benchmark 

Tucson 

Benchmark 

(kWh) 

Armory 

Park del 

Sol 

(kWh) 

Energy 

Savings 

Cooling 7,958 2,487 -69% 

Heating 2,146 811 -62% 

Hot Water 2,410 2,410 -0.0% 

Lighting 2,351 1,776 -25% 

Appliances 1,969 1,942 -1% 

Miscellaneous 3,471 3,471 0.0% 

Total (without solar) 20,305 12,897 -37% 

Solar Hot Water 920 

Solar PV System 2,491 

Total (with solar) 20,305 9,486 -53% 

Measuring Up 

An analysis of energy use for the prototype home in comparison to the Benchmark for Tucson 

shows that the Armory Park del Sol homes were estimated to consume 37% less energy, not 

including the solar systems savings. The energy continues to reduce to 53% when including the 

solar hot water and PV systems. Table 12 shows a breakdown of the primary energy uses. 

When analyzing utility bills for a number of homes similar to the prototype, an average of 9,730 

kWh was shown as being purchased. These data includes the solar hot water and PV system 

supply to the home – proof that a well-designed and constructed energy-efficient home does live 

up to its reputation. 

A Solar Community Develops 

As a builder and developer, John Wesley Miller Companies arranged the lots in the Armory Park 

del Sol subdivision so that each home could have optimal orientation for a solar PV and hotwater system. The covenants, codes, and restrictions for the development govern the placement 

and maximum height of trees to avoid shading on the rooftop solar systems. Desert-style parapet 

walls are ideal in keeping solar hot water and PV panels out of sight. 
116 

Solid Construction 

In the Tucson climate, Miller feels, masonry construction adds a lot of value to the company’s 

homes. JWM Companies’ wall system, which consists of CMUs with solid grout, R-12 exterior 

rigid foam, and interior steel-framed walls, produces a tight house (2.9 ACH50) with little 

additional air sealing required. Because plumbing and electrical lines run through the interior 

steel-framed walls and all ducts are in the conditioned space, no additional air sealing is needed 

for mechanical penetrations. 

Concrete construction provides a thermal mass to temper the extreme heat and cold of the desert 

climate. Miller explains that the thermal mass property of solid-grout concrete block, combined 

with exterior insulation, helps temper the indoor environment from the extreme outdoor 

conditions. In addition, people are willing to pay for the quality of the company’s masonry 

construction. “The resale value is much higher for masonry,” Miller says. 

Selective about Windows 

Spectrally selective coatings on the windows offer protection from the brutal Tucson heat and 

sun. Having a low U-value of 0.32 prevents conduction of heat indoors and heat loss during the 

cool nights. The low SHGC of 0.30 helps mitigate direct solar heat gain during the summer 

months. 

Engineering the HVAC System 

As part of the design team, a local professional engineer conducts an analysis on all plans for 

proper sizing of HVAC equipment and location of ductwork. Miller relies on the engineer, who 

he describes as a “practical guy who grew up in the tin-bending business.” 

The high ceilings and architectural features, combined with a knowledgeable HVAC engineer, 

make it possible for the company to bring all the ductwork into a conditioned space. The ducts 

are enclosed in soffits below the insulation along the central core of the house plan. All ducts are 

sealed with mastic and tested for leakage. A central return, as well as transfer grilles across 

interior doorways, helps equalize the pressure throughout the house. 

Exploring and Experimenting 

JWM Companies is constantly seeking new and interesting building techniques and materials. 

Consideration is given to the cost of new features. However, according to John Wesley Miller, it 

isn’t always the only consideration. Miller said, “A lot of what we do is trying something to see 

if it works instead of adopting only what is proven. We don’t always look at the cost-benefit 

analysis. I like to explore and experiment and try things to see what happens. It’s research and 

it’s fun.” In addition, practicality often factors into Miller’s decision to use a new product; 

products must be locally available and must fit neatly into the construction schedule. 

To this end, JWM Companies relies heavily on the subcontractors with which it has loyal and 

longstanding relationships. The company works closely with the trade contractors to determine 

the best materials, production, and processes to minimize energy use and take advantage of the 

abundant solar resource. Periodic meetings with staff and trades are held to review building 

practices, identify problems, and implement solutions. 
117 

Builders as Environmentalists 

As John Wesley Miller summarizes, “Builders are the environmentalists because we construct 

the built environment. We have the opportunity to improve that built environment every day and 

every year, to provide a higher quality of life. We are the ones that can raise the bar to which all 

of us strive. That’s what we, as builders, can do to improve people’s quality of life.” 

Utility Inspiration and Perspiration 

Efficiency features make the cost of heating and cooling very low. According to an independent 

study, the utilities for an average home in the Armory Park del Sol subdivision run about half of 

what a typical new home in the city costs. Through a synergistic partnership with Tucson 

Electric Power (TEP), the home’s heating and cooling bills are guaranteed not to exceed $0.76 

per day for 5 years. 

Under the TEP program, periodic quality inspections are performed - at the framing, insulation, 

and HVAC phases - plus a final inspection. The builder can be assured that the house was 

constructed as designed; TEP adds a new house to its customer base that sends power to the 

utility grid at times when TEP needs it most; and the customer’s utility bills are guaranteed to 

fall below a certain amount each month. 

Inspections include performance testing to check whole-house air leakage, duct leakage, and 

pressure in each room with the doors closed. Reducing the pressure difference across interior 

doorways facilitates air circulation to all rooms and results in a more comfortable home. 

A Good Deal 

Each home in the subdivision features a solar electric and solar hot-water system. John Wesley 

Miller Companies has the advantage of working with a progressive utility company that is 

aggressively encouraging the installation of renewable energy power systems. Currently, the 

rebate for solar systems is $3 per installed watt. Therefore, all new homes in Armory Park del 

Sol are getting a $4,500 rebate from the power company, in addition to lower energy bills, for 

their 1.5-kW photovoltaic system. In turn, Arizona provides a $1,000 tax credit for solar water 

heating and solar electric systems. 

Builder Innovation, Challenges, and Lessons Learned 

Though constructing homes for more than 50 years, JWM continues to search for new 

opportunities to improve his product and process. While most homes constructed in the area 

have switched to light-frame materials, the Armory Park del Sol homes are constructed of solid 

grout block, with the insulation attached to the exterior of the block leaving the interior surface 

to be finished with a skim coat of plaster, and a stable exterior surface that reduces stucco cracks. 

The comfortable and solid feel to the wall are major selling points that differentiate JWM from 

the competition. In addition, the homes use a parallel-piping system for the hot-water plumbing, 

one of the lessons learned from early homes to improve hot water delivery time and reduce water 

use. And although popular with some customers, the builder has stopped the use of recessed 

light fixtures because of the energy penalties that are difficult to overcome. 
118 

For builders in a sunny desert climate looking to improve energy efficiency, Miller feels that 

builders should install a solar hot water system. Next, he recommends looking at windows with 

low U-factors and low SHGC. He suggests that builders should look at the value of thermal mass 

storage with masonry walls and exterior insulation. Finally, he adds, “Everyone should be 

insulating concrete slab foundations. A tremendous amount of heat goes out through the slab in 

the winter.” 

Snapshot of Energy Features 

Floor Area 1,916 ft2

Construction Cost $148 per ft2

Number of floors one-story; slab-on-grade 

Foundation Insulation R-12 slab-edge insulation 

Wall Construction and Insulation 8-in. solid-grout CMU; 

R-12 exterior rigid foam 

Ceiling/Roof Construction and Insulation I-joists/flat roof; 

R-38 fiberglass batt insulation 

Windows Low-E, gas-filled; U = 0.32; 

SHGC = 0.30 

Air Sealing Foam around rough openings of 

windows and doors 

Blower Door Test 2.9 ACH50

Ducts 100% conditioned space; 

R-6 insulation 

Duct Losses 15 cfm total at 25 Pascals 

Ventilation Passive inlet to return side of air handler 

Heating Equipment HPSF 8.6 heat pump with 

programmable thermostat 

Cooling Equipment 12 SEER heat pump 

Hot Water System Batch-type solar water heating system 

with tankless back-up 

Solar PV System 1.5-kW grid-connected photovoltaic 

system 

Lighting Combination incandescent and 

fluorescent 

Appliances ENERGY STAR® refrigerator (643 

kWh/yr) and dishwasher (449 kWh/yr) 

HERS Score 91.8 
119 

Development: Gamlen House 

Builder: Artistic Homes 

Location: Albuquerque, New Mexico 

The home is a 2700-ft2

, four-bedroom, three-bathroom, single-story home with an unvented 

conditioned crawlspace below (Figures 33, 34, 35). Key features include well-insulated building 

envelope, low-e windows, ducts and air handler in conditioned space, ENERGY STAR 

dishwasher, supply ventilation system, and a condensing gas furnace for water and space heating.

Figure 33. Gamlen House floor plan 
120 

Figure 34. Gamlen House front elevation 

Figure 35. Gamlen House rear elevation 
121 

House Specifications 

Specifications are provided in Table 13. 

Table 13. Specifications for Artistic Homes: Gamlen Residence, 

Albuquerque, New Mexico 

Benchmark 

Construction 

Building America/EFLTM 

Platinum 

Estimated 

Cost $ 

Building 

envelope 

Ceiling R-33 on flat vented attic

R-38 attic loose fill 

fiberglass $150 

Walls R-11.7 16 oc 

R-23 2x6 24 oc + 

R-1.2 asphalt impregnated $0* 

 

sheathing to exterior, 

OSB on corners - 

 

cavity insulation Optima 

dry-blown fiberglass - 

R-23 2x6 24 oc - 

Crawl Space 

Walls R-13.7 on walls 

R-14 2-in. Polyisocyanurate 

Rigid Insulation $150 

Windows Single-pane TIM frame Double-glazed Low-E2

 vinyl $1,000 

 U = 0.44, SHGC = 0.55 

vinyl frame; U = 0.35, 

SHGC = 0.35 - 

Infiltration 186 ELA 

2.5 in.2 leakage area per 

100 ft2 envelope $0 

 
122 

Table 13 (continued). Specifications for Artistic Homes: 

Gamlen Residence, Albuquerque, New Mexico 

Benchmark 

Construction 

Building America/EFLTM 

Platinum 

Estimated 

Cost $ 

Mechanical 

systems 

Heat 

78% AFUE in vented 

attic 

90%+ AFUE in 

conditioned floor area $1,000 

Cooling 10 SEER A/C 13 SEER A/C - 

DHW 

0.54 naturally 

aspirating gas water 

heater in garage 

0.86 EF condensing gas 

furnace in garage - 

Ducts 

metal ducts in 

conditioned crawl 

metal ducts in 

conditioned crawl $0 

Leakage 15% of flow 

None (5% or less of 

nominal flow to outside) $0 

Ventilation none 

Aircycler FR-V with 

manual damper $150 

 

Resulting 2 ton 

Downsizing -$1,000 

 Total = $1,450 
123 

Specifications 

Building America

Building envelope

Ceiling R-38 attic loose fill fiberglass

Walls R-23 2x6 24 oc + R-1.2 asphalt impregnated

sheathing to exterior, OSB on corners

cavity insulation Optima dry-blown fiberglass

R-23 2x6 24 oc + FC drywall to garage

Crawl Space Walls R-14 2" Polyisocyanurate Rigid Insulation

Windows Double glazed LoE2

 vinyl

 vinyl frame; U=0.35, SHGC=0.35

Infiltration 2.5 sq in leakage area per 100 sf envelope

Mechanical systems

Heat Lennox CompleteHeat® Combo System AM30Q2/3-70

90% CAAFUE in conditioned space

Cooling 13 SEER A/C (First Air-Lennox)

DHW Lennox CompleteHeat® Combo System HN30-100

0.86 CAEF 34 gal in garage

Ducts sheet metal & flex in conditioned crawlspace

Leakage None (to outside; 5% or less)

Ventilation AirCyclerTM Supply-only system

10 minutes on; 20 minutes off
124 

Innovative Features 

Supply Ventilation System 

A supply-only ventilation system is specified. An outside air duct is run from the outside 

(through a gable end) to the return side of the air handler. The running air handler pulls outside 

air into the return system. A flow regulator or adjustable damper provides fixed outside air 

supply quantities independent of air-handler blower speed, and the HVAC system provides 

circulation and tempering. In addition to the flow regulator, an electrically operated damper will 

be installed to prevent excess ventilation during peak-load usage. This damper will 

automatically close the fresh-air duct to prevent outside air from diluting the conditioned air too 

much. This unit should be available through most HVAC contractors. 

Continuous running of the air handler in order to draw ventilation air is not recommended. An 

AirCyclerTM FR-V controller is suggested to run air handler periodically; it operates the fan only 

after a selected amount of time following last operation. Furthermore, this system reduces 

stagnation in the house by providing mixing of house air and controls the electrically operated 

damper to prevent over mixing. 

Conditioned Crawl Space 

This was Artistic Homes’ first conditioned crawlspace. The design’s intent was to ensure that 

the home would have the same outside appearance as the slab-on-grade product. This meant that 

the top of the floor had to be within 8 in. of grade. The detail shown below was the one chosen 

to accomplish this. The absence of a rim joist contributed to the tightness of the conditioned 

crawl as noticed in the blower-door tests (Figure 36). 

Builder Cost Summary 

Builder costs have been individually priced and the associated downsizing savings have been 

included to show net cost. 

Figure 36. Rim joist

The absence of a 

rim joist means 

fewer joints that 

leak 
125 

Utility Information 

Gas PNM $0.4226 per therm + $9.00/month 

Electricity PNM 0-200 = $0.0720 per kWh 

 200+ = $0.0843 per kWh + $3.00/month 

Source Energy Consumption Summary 

The simulations have been updated with a multi-point blower door and single-point duct blaster, 

as well as a measured outside air intake flow. The savings increased by 5% as a result of the 

improved tightness and negligible duct leakage to outside. 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 14 and Table 15). 

Table 14. Source Energy Consumption Summary 

Percent of End-Use Percent of Total

Benchmark Proto Proto savings Proto savings

End-Use 106

 BTU/yr 106 BTU/yr

Space Heating 109 58 47% 19%

Space Cooling 29 13 55% 6%

DHW 31 21 33% 4%

Lighting* 27 27 0% 0%

Appliances + Plug 76 76 0% 0%

OA Ventilation** 0 0 0% 0%

Total Usage 274 195 29% 29%

Site Generation 0 0 0%

Net Energy Use 274 195 29% 29%

Source Energy Savings

Estimated Annual Source Energy
126 

Table 15. Measured Data 

SNAPSHOT© “The Form”

Lot #: 9 

Model: Gamlen

Subdivision: 

 Primerose 

Address: 

 8609 Royaglo 

Date and time: 

9/24/03 2:15 PM 

INITIALIZATION

 Square feet 2700 ft2

 Surface area (all outside surfaces, including foundation) 9226 ft2

 Volume 32997 cu. ft.

 Windspeed (approximate mph) ~ 0 mph

 Outside temperature (estimated) 80 o F

 Check that all registers and bedroom doors are open Yes No

 Static pressure in Supply and Return S +5 Pa / R -32 Pa 

 Is there a ventilation system? Yes No

 Type of ventilation system (e.g., exhaust-only, HRV, ERV) Air Cycler Supply 

Only 

 If there is an AirCyclerTM, enter the off / on times off 24 on 8 

 Enter outside air duct pressure -35.4 pa

 Type of outside air duct (flex/sheet metal; diameter) 6-in. insulated flex 

 Is there an adjustable outside air damper? Yes No

 Is there a fireplace or wood stove? Yes No

 Duct location (approximate % in attic, conditioned space, 

basement, etc.) 

100 % Conditioned 

Crawl 

PRESSURE TESTING

 Stack Pressure (baseline with blower door installed; covers on) -0.1 pa

 Dominant Duct Leak Effect (baseline with HVAC system running) pa

 Master Bedroom Door Closure Effect (∆P from main space to 

outdoors) 

 pa

 All Doors Closed Effect (∆P from main space to outdoors) pa

 Fireplace/Wood Stove Zone HVAC Test pa

 p

a

 p

a

 Pressure In Each Closed Room. Not 

available on initial test; no doors were 

installed. p

a

 p

a
127 

Table 15 (continued). Measured Data 

BLOWER DOOR TESTING (BDT)

 Blower Door Location and Test Goal Front Door (Goal = 2310 CFM 50) 

 Test 1: Transfer grilles open, hatches 

closed 

CFM50=1217, LR = 0.13, C = 82.6, n = 0.688, 

R2 = 0.99965 

 Test 2: Transfer grilles open, hatches 

open 

CFM50 = 1214, LR = 0.13, C = 80.0, n = 0.695, 

R2 = 0.99953 

 Test 3: Transfer grilles closed, 

hatches closed 

CFM50 = 1216, LR = 0.13, C = 87.7, n = 0.672, 

R2 = 0.99928 

DUCT AIRTIGHTNESS TESTING (DAT) 

 DAT CFM25 TOTAL 125 Pa 25 Ring 2 170 CFM 25 

 DAT CFM25 OUTSIDE 0 Pa 25 Ring 3 ~0 CFM 25 

AIR HANDLER FLOW MEASUREMENT (TRUEFLOW located at return) 

 DG700 Reading NSOP = ~5.4 Pa, TFSOP = ~4.5 Pa, Cooling Flow = 995 CFM 

 DG700 Reading NSOP = ~5.0 Pa, TFSOP = ~4.7 Pa, Heating Flow= 775 CFM 

MECHANICALS 

 Furnace or air 

handler 

Make: Lennox CompleteHeat© Model: AM30Q2/3-70 

 Air Conditioning Make: Lennox Model: HS26-030-4P 

 Cooling Coil Make: Model: BV 124 36-BPA23 

9GL58 

 Domestic hot water Make: Lennox CompleteHeat© Model: HM61-100-1 
128 

Community-Scale Case Studies 

Development: Premier Gardens 

Builder: Premier Homes 

Location: Rancho Cordova, California 

Introduction 

The Zero Energy Homes (ZEH) in the Premier Homes development – “Premier Gardens” 

(Figures 37, 38, 39) is located in Rancho Cordova, California. The Sacramento Municipal 

Utility District (SMUD) is a primary sponsor and research partner with the Building America 

Program on this project. SMUD cost shared a portion of the incremental costs of the energy 

efficiency and renewable energy upgrades for the Premier homes. In addition, SMUD has 

instrumented 19 homes in the ZEH development and a nearby non-ZEH subdivision and is 

collecting and analyzing performance data on these homes to help evaluate the relative impact of 

ZEH features on peak and total energy consumption of the homes. A 2.4-kW DC buildingintegrated photovoltaic system is installed in each ZEH home. With building energy-efficient 

features, appliances, other appliance/plug loads and fluorescent lighting alone, the homes have 

achieved around 35% energy savings without PV system and around 60% energy savings with 

PV system. 

Figure 37. Premier Garden Homes site plan and elevation
129 

Figure 38. Aerial view of Premier Gardens (Premier Homes 

photograph courtesy of SMUD) 

Figure 39. Floor Plan 1503 ft2 (Lot 68) – (three bedroom, two baths, 

and one-car garage) 
130 

House Specifications 

To achieve 60% energy savings below the base case house, the Prototype BAP House requires 

the following advanced systems: 

• R-38 attic insulation (U-value = 0.031). High insulation reduces heat gain in summer and 

reduces heat loss in winter. 

• R-13 fiberglass batts + 1-in. EPS foam (U-value = 0.067). This U-value reflects 25% 

framing factor. 

• 3.5 SLA or low air infiltration rate. Tight building envelope to help minimize outside/inside 

air from entering/exiting the home. With lower infiltration of unconditioned air and 

exfiltration of conditioned air, less conditioning is required, making the home more efficient. 

Homes with low air infiltration/exfiltration are often quieter and cleaner. 

• Dual-pane non-metal frame windows with spectrally selective glass with U- factor and 

SHGC no greater than that listed in Table 16. 

These types of glazing help increase the comfort level of the home by reducing solar insolation 

into the house. In the summer, spectrally selective glass lets in visible sunlight while blocking 

80% of both the infrared and ultraviolet solar energy (that drives up cooling costs and degrades 

curtains, window treatments, carpeting and furnishings). In the winter, these glazing products 

offer reduced heating costs by reflecting room-side radiant heat back into the room.57 In hot 

climates this type of glazing typically enables builders to reduce the size of air conditioners and 

decrease other building energy related features. 

• Engineered System with Heating Ventilating and Air Conditioning (HVAC) efficiencies of 

91% AFUE for furnace and 14 SEER for air conditioning with thermal expansion valve 

(TXV). Licensed mechanical engineers size and select HVAC systems, design duct sizes, 

and register locations. The final engineered systems will have properly sized and balanced 

Table 16. U-values and SHGC values for doors

 

57 Supplemental Catalogue for Cardinal IG: LoE2

 Glass Products “The Choice for Year-Round Energy Savings and 

Comfort” 

 U-value SHGC 

Slider 0.36 0.30 

Single Hung 0.33 0.32 

Fixed 0.30 0.33 

Sliding Patio Door 0.34 0.30 

French Door 0.33 0.28 
131 

HVAC systems with correct duct sizes and placement of registers, this will assure the 

conditioned air to be evenly distributed throughout the whole house. They will also provide 

improve efficiency and comfort. The TXV is a metering device for refrigerant flow into the 

evaporator of an air conditioner. A TXV improves efficiency. 

• R-4.2 buried in insulation (R-13 equivalent) with tight duct and ACCA Manual D designed 

by a licensed mechanical engineer. Duct leakage can have a significant impact on HVAC 

performance, household infiltration/exfiltration rates, moisture levels in the house, water 

heater and furnace safety, and overall occupant comfort. A tight duct system is one that does 

not leak more than 6% of the fan airflow (at 50 Pascal). Excessive air leakages in duct 

systems make HVAC systems work harder, using more time and energy to cool or heat the 

home as a result of insufficient air delivery. This results in higher energy bills and less 

comfort for homeowners/occupants, which often triggers callbacks. Duct leakage typically 

occurs at these locations: 

• Poorly fitted and improperly sealed joints and seams in the ductwork 

• Disconnected and partially disconnected boot connections 

• Holes in the ducts 

• Use of improperly sealed building cavities for supply and return ducts 

• Poor connections between room registers and register boots 

• Poorly fitted air handler doors, filter doors and air handler cabinets. 

Tight duct systems increase forced-air distribution efficiency, resulting in improved comfort and 

lower utility bills for homeowners. Tight ducts are required to be tested by a third party. 

• One tankless water heater with a minimum Energy Factor (EF) of 0.82. R-4 insulation on all 

trunk lines. This includes any hot water lines located in concrete slabs or underground. A 

tankless water heater has high efficiencies. Hot water is heated upon demand and has no 

storage tank. 

• All-fluorescent lighting. The wide variety of improved quality, more efficient lighting that 

are on the market today warrant more careful lighting design. Lighting plans are 

recommended and fluorescent lamps used wherever possible. Where possible, bayonetmount fluorescent should be used in compact-fluorescent fixtures. Where this is not possible, 

medium-base CFLs are permitted. Minimum recommended downlight specifications of 

fluorescent lamps should be 2700K in cooler temperature, 23-26 watts, and 1300 lumens 

(used 26 watts). Vanity lighting requirements may vary. 

• Gas dryer stub. This is provided to encourage the use of gas dryers, which are less expensive 

to operate than electric. 

• Photovoltaic System. The 2.4-kW DC system by GE Energy produces on average 3420 

kWh/year (or 285 kWh/month). The building-integrated PV system not only produces 

electricity, but is also aesthetically pleasing by blending in with the roof tiles. 
132 

Calculated Energy Performance 

Table 17 lists the energy savings of the base case house compared to the prototype house. 

Table 17. Lot 68 (1503 ft2) Summary of Energy Savings (Micropas Simulation) 

 Base Case 

House 

Prototype 

House 

Energy 

savings 

Heating (from Micropas simulation) 33,863 kBtu/yr 16,849 kBtu/yr 50% 

Cooling (from Micropas simulation) 21,252 kBtu/yr 5,095 kBtu/yr 76% 

Water Heating (from Micropas 

simulation) 

22,951 kBtu/yr 13,076 kBtu/yr 43% 

Lighting 20,550 kBtu/yr 5,345 kBtu/yr 74% 

Other Uses/Appliances/Plug Loads 51,009 kBtu/yr 49,659 kBtu/yr 2.5 % 

Whole House Energy Savings 149,624 90,023 39% 

Site Generation 

(2.4-kW DC PV system) 

-35,017 

kBtu/yr

Total 149,624 

kBtu/yr 

55,006 

kBtu/yr 

63% 
133 

Development: Lakeside 

Builder: Morrison Homes 

Location: Elk Grove, California 

Morrison Homes at Lakeside is located within the master-planned community of Lakeside in the 

“hometown” of Elk Grove, 25 miles south of Sacramento, California (Figure 40). Lakeside is 

one of the first homes under the U.S. Department of Energy’s Zero Energy Homes (ZEH) 

initiative, in the Sacramento area. SMUD and ConSol were both invited by Morrison Homes to 

help them with the Lakeside project. This is a 120-home development with 12 homes being 

ZEH. Five home plans are available – and all are available with the ZEH package. Floor plans 

range from 2,126 ft2

 up to 3,672 ft2. The community was originally designed with ZEH in mind, 

but no special architectural design was required for the reduced-energy homes. In addition, ZEH 

is an option available on most of the remainder of the regular homes, with a few exceptions 

where the roof’s solar exposure is not optimal. Monitoring equipment has been installed on the 

model home. The Sacramento Municipal Utility District (SMUD) installed sensors for 

determining solar insolation and PV panel temperatures (Figure 41). SMUD provided 

considerable expertise aiding Morrison with solar features as well as providing hookup fee 

discounts related to home energy efficiency measures, incentives for efficient lighting and 

Energy Star home certification as well as PV buydowns. ConSol provided technical expertise to 

develop the efficiency package that, combined with the solar was agreeable to all to meet DOE, 

SMUD and Morrison objectives. ConSol and SMUD provided marketing support for the project. 

Figure 40. Morrison Homes in Elk Grove, California 
134 

Figure 41. Typical plan floor plan, Lakeside, California 
135 

Innovative Energy-Efficient Features 

The following is a list of all the energy efficient features deployed in the ZEH home: 

Appliances ENERGY STAR® 

Air Sealing Caulking and sealing measures ensure low air infiltration 

Insulation R-19 wall insulation

R-30 second-story floor insulation (two-story plans)

R-38 attic insulation

R-6 duct insulation - Plans 1 and 4 

Windows Spectrally selective glass, high-performance windows, U-factor: 0.36 

for sliders, 0.33 for fixed, 0.35 for patio door; SHGC: 0.33 for sliders, 

0.36 for fixed, 0.35 for patio door

Heating/Cooling 0.92 AFUE furnace

14 SEER A/C

Lighting All fluorescent lighting

Water Heating Tankless water heater with 0.82 energy rating 

Hot water pipe insulation

Photovoltaics 2-kW roof-integrated photovoltaic tile system 
136 

Energy and Cost Savings 

Tables 18 and 19 list the energy and cost savings for Plan 2 with an area of 2513 ft2

. 

Table 18. Energy Savings for Base Case and Prototype House 

Base Case / BA 

Benchmark House 

(kBtu/yr)

Prototype House - 

40% Energy Savings 

Features (kBtu/yr)

Reduction in 

Energy Use 

(kBtu/yr)

Heating 62,951 35,458

Cooling 34,554 7,665

Water Heating 27,744 17,516 

Total 125248 60639 51.6%

Lighting 28,823 14,335 

Total (Heat, Cool, WH and Lighting) 154,071 74,973 51%

Other Uses 71,835 70,039 

Total (Heat, Cool, WH, Lighting & Other Uses) 225,905 145,012 36%

 -

Energy Savings 225,905 145,012 36%
137 

Table 19. Energy Savings for Base Case and Building America Benchmark House 

Dollars Dollars

Therms kWh $ Therms kWh $

Energy Code Related

Space Heating 630 $ 629.51 355 354.58$ 

Space Cooling 506.21 3,375 $ 112.29 749 $ 

Water Heating 277 $ 277.44 175 175.16$ 

Other Uses

 cooking 78 $ 78 78.00 78.00$ 

 dishwasher 41.25 275 $ 41.25$ 275

 electric or gas dryer 166.95 1,113 $ 96 $ 96.00

 refrigerator 100.35 669 $ 100.35 669 $ 

 Miscellaneous (Appliances 

+ Plug) 629.51 4,197 $ 629.51$ 4,197

Lighting 422.25 2,815 $ 210.00$ 1,400

reduce kWh by solar 

contribution n/a n/a (3,420) (513.00) $ 

Total use 985 12,443 2,851.46 $ 704 3,869 1,284.13

Total Annual Energy Use kBtu/yr 225,902 kBtu/yr 109,992

Reduction in Energy Use 100% 29% 69% 55%

Total for Column in kBtu/yr 127,408 98,494 70,374 39,618 

Total kBtu/yr for BA 

Benchmark House kBtu/yr 225,902

Total kBtu/yr for Prototype 

House kBtu/yr 109,992

Percent End Use Energy 

Savings 51.3%

Estimated Montly Energy Bill $ /mo 237.62 $ /mo 107.01

Reduction in Energy Cost 45%

price of gas/therm $1.00

price of electricity/kWh $0.15

Base Case / BA Benchmark 

House

BA Prototype House - 40% Energy 

Savings (Upgraded Features, 

Fluorescent, Gas Dryer Stub and 

Tankless Hot Water)

\ Energy Use
138 

Development: Windemere 

Builder: Centex Homes, Northern California Division 

Location: San Ramon, California 

Windemere development contains two neighborhoods that are included in the program; Aventura 

and Lunaria (Figures 42 and 43). Two energy package options were developed for Centex 

Homes: basic PowerSave and PowerSave Plus. A model home in each of the neighborhoods was 

selected to demonstrate the PowerSave Plus option, and a total of 25 homes were pre-plotted 

with the basic PowerSave features within both neighborhoods. The basic PowerSave option 

meets the 30% Building America goal and are described in this section. Details of the 

PowerSave Plus home are not included here because source energy savings exceed 39% on 

efficiency measures. All of the homes in these two neighborhoods are two stories and range in 

size from 2,250 ft2

 to 3,800 ft2. Construction of the models began in September 2003, and all 

homes will be completed by October 2005. There are two additional neighborhoods, Torello and 

Montevego, with models in construction that will offer these same options. 

Table 20 lists the final group of measures included in the final PowerSave option package. Two 

measures that were being considered for inclusion in the PowerSave designs were implemented 

throughout the two communities, leading to spin-off energy savings for all homes. These 

measures, zero defect insulation and insulated headers, were adopted for both the Aventura and 

Lunaria communities. Zero defect wall insulation was achieved by employing a blown-in 

fiberglass insulation product. The small incremental cost compared to fiberglass batts 

encouraged Centex to use it on all homes. 

Insulated headers were initially rejected because the manufacturer did not make headers in the 

sizes used by Centex. After the manufacturer accommodated Centex by expanding their product 

line, they were rejected a second time because the recess between the stud face and the header 

made nailing of siding difficult. The manufacturer then offered to use scrap material to fill in the 

recess, and Centex adopted the header for universal application. The cost of the insulated 

headers proved to be less than the cost of linear strand lumber (LSL) wood headers. 

Source Energy Consumption Summary 

Tables 21 and 22 list source energy use and savings for the Aventura and Lunaria 

neighborhoods. Savings are relative to the Benchmark. The standard Centex models meet Title 

24 and ComfortWise performance requirements. 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. 
139 

Table 20. House Specifications Centex ─ Building America PowerSave Home 

Building Envelope 

Ceiling R-48 blown fiberglass in attic 

Walls Zero defect wall insulation: R-15 blown fiberglass 2X4 

16 in. oc. with insulated window and door headers 

Floor Slab-on-grade, uninsulated 

Windows Double-glazed vinyl windows Low-E2

U-factor = 0.35 Btu/hr-ft2-°F, SHGC = 0.37 

Infiltration Tight construction, including draft stops, caulking of top 

plate penetrations and windows, and bottom plate 

gaskets. Tested to be less than 3.9 SLA 

Mechanical Systems 

Heating Carrier 80% AFUE variable-speed furnace 

Cooling Carrier 10 SEER condensing unit 

Ducts R-4.2 flex ducts buried in R-49 attic insulation. 

Tested tight ducts < % leakage 

Water Heating Takagi Instantaneous water heater (0.82 EF) 

PEX Home-run piping design 

Lighting CFL’s on all permanent fixtures except dining chandelier 

Figure 42. Aventura – front elevation Figure 43. Lunaria – front elevation 
140 

Table 21. Aventura Summary of Estimated End-Use Source Energy 

Estimated Annual Source Energy Source Energy Savings 

 Benchmark 

Centex 

Standard Prototype Percent of End-Use Percen

End Use (MBtu/yr) (MBtu/yr) (MBtu/yr) vs. Benchmark vs. Standard vs. Benchmark 

Space Heating 38 27 24 37% 12% 8% 

Space Cooling 47 43 38 20% 13% 5% DHW 32 32 14 54% 54% 9% Lighting 21 21 7 67% 67% 8% Appliances+ Plug 42 42 42 0% 0% 0% OA Ventilation 0 0 0 0% 0% 0% Total Usage 180 165 125 30% 24% 30% 
141 

Table 22. Lunaria Summary of Estimated End-Use Source Energy 

Estimated Annual Source Energy Source Energy Savings 

 Benchmark 

Centex 

Standard Prototype Percent of End-Use Percen

End Use (MBtu/yr) (MBtu/yr) (MBtu/yr) vs. Benchmark vs. Standard vs. Benchmark 

Space Heating 72 64 59 19% 8% 5% 

Space Cooling 68 46 39 43% 15% 12% DHW 38 16 58% 58% 9% Lighting 28 28 9 67% 67% 7% Appliances+ Plug 44 44 44 0% 0% 0% OA Ventilation 0 0 0 0% 0% 0% Total Usage 250 167 33% 24% 33% 
142 

Builder Cost Summary 

The basic PowerSave package was pre-plotted on 25 lots in the two neighborhoods; six in 

Aventura and 19 in Lunaria. The package was also offered as an option for the remaining 

homes. Centex offered the basic PowerSave option for $3,600 for Aventura and $3,850 for the 

bigger homes in Lunaria. Table 23 summarizes the incremental costs to the builder, and Table 

24 summarizes the PowerSave cash-flow analysis for the buyer. Estimated incremental costs in 

Table 24 were obtained from the builder. Amortized costs are based on a 30-year mortgage at 

6% interest. Buyer surveys indicated some interest in the PowerSave package, but it appears 

that interested parties purchased the pre-plotted homes instead of purchasing a standard home 

with the PowerSave option. 

Table 23. Centex Windemere PowerSave Pricing 

 Standard Construction Building America - 

PowerSave 

Estimated 

Cost $ 

Building envelope 

Ceiling R-38 batt in vented attic R-49 blown fiberglass $700-$800 

Walls R-13 2x4 16 in. oc R-15 blown 

fiberglass. $100 

Headers LSL Headers Insulated headers $0 

Mechanical 

systems 

DHW 0.54 EF storage gas 

water heater in garage 

0.82 EF 

instantaneous gas 

water heater in 

garage 

 $1,200 

Ducts R-4.2 suspended from 

trusses 

R-4.2 buried in ceiling 

insulation $0 

Lighting Incandescent Lighting Full CFL Package $375 

 Total = $2,375-

$2475 
143 

Table 24. PowerSave Cash Flows 

Package Aventura Lunaria 

Total Cost $3,600 $3,850 

Annual Amortized 

Cost 

$259 $277 

Annual Energy Savings $452 $598 

Net Savings $193 $321 
144 

Appendix A: Passive Solar Design Considerations 

There are three primary passive design systems: direct gain, indirect gain, and sunrooms. 

Direct Gain. In direct gain (Figure A-1), the sun shines directly into the house through 

windows, skylights, and clerestories. Depending on the amount and orientation of glazing, 

thermal mass materials may be needed to be incorporated in walls and floors to absorb the solar 

radiation and re-release it during the evening. Direct gain can also utilize a strategy called “sun 

tempering” where glazing is favored on the south side, but limited so that additional thermal 

mass is not necessary to prevent overheating of south-facing rooms. 

Figure A-1. Direct Solar Gain 

Indirect Gain. Indirect gain (Figure A-2), also called thermal storage wall and Trombe Wall, 

consists of a thermal mass wall, with direct southern exposure. For example, a thermal storage 

wall could be a poured-in-place concrete wall or a concrete masonry block wall with the cores 

filled with concrete. One or more panes of glazing are located immediately on the outside of 

these mass walls. The outside surface of the mass wall is painted a dark color or coated with a 

selective surface, such as those used in active solar collectors. 

Figure A-2. Indirect Solar Gain 
145 

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. Simply by orienting homes with longer sides with larger glazing areas facing 

north-south helps to minimize unwanted heat gain in summer and maximize beneficial solar 

heat gains in winter (Figure A-4). 

Builders seeking to optimize individual home and lot orientation can follow these guidelines. 

Figure A-4. The paths of the sun in winter and summer over a home with long sides 

facing north and south 
146 

• Minimize East and West Glazing. Orienting homes so that the sides with the least glazing 

face east and west can significantly reduce cooling loads and reduce glare. Typically, 

afternoon sun shining in west windows is most important to minimize or to shade. 

• North-south Orientation. Having the longer sides of homes facing north-south is beneficial 

for reducing both heating and cooling loads. In Cold Climates, having more glazing face 

south with adequate shading can minimize cooling and heating loads significantly; however, 

this must be carefully designed to prevent overheating and comfort complaints. South 

windows can most easily be shaded with overhangs. 

• Architectural Design. Shape the architectural form and solar apertures of the houses to 

optimize passive solar heating, including appropriate mass to avoid localized overheating, 

and summertime shading to mitigate cooling loads. This is best done in conjunction with 

hourly energy and room temperature modeling to assure energy savings and occupant 

comfort. Passive designs typically employ increased use of dense materials like concrete slab 

floors with tile and increased thickness of drywall or interior brick or concrete walls that 

have high conductivity to heat and high heat capacities. The increased mass can be as simple 

as replacing carpeted floors with inexpensive tile floors in slab-on-grade construction. If 

mass materials are warmed by winter sun and cooled with night ventilation systems in 

summer, they can add to comfort and reduce use of and consumption by conventional heating 

and cooling systems. 

• Night Cooling: Locate openings to optimize airflow during temperate conditions and to 

facilitate “night flushing” of heat built up over the day during the relatively cooler evening 

hours. 

Passive design may have a significant impact on the architectural character of the house and may 

be viewed in a positive or negative manner by builders and homebuyers. Passive strategies may 

be pursued as a trade-off for other energy improvements; however, careful consideration of 

occupant comfort must be taken into account. Effective passive solar heat gain can be very 

beneficial during the heating season, but it is challenging to design well and requires proper 

linkage of aperture and thermal storage in order to be useful and to avoid discomfort. 

Overheating is a significant problem. Passive cooling, both by window shading and glass 

transmission characteristics, is very beneficial during the cooling season. Window shading can 

be very effective, but its proper design is critical, and the shading elements may have a strong 

visual impact on the exterior of the house. Thus, it is not a strategy that is thought to be 

universally appropriate at the 30% improvement level. For more information on passive design 

strategies, see the Passive Solar Industries Council’s passive solar design guidelines.58

Architectural Shading Considerations. Shading, like orientation, is not required to achieve 

30% savings, particularly with low-SHGC glazing. However, studies have shown that shading 

can cut solar heat gain by anywhere from 10% to 50%. Blocking the sun's rays from striking 

glazing areas and heating up a home is much more efficient than using air conditioning to cool 

down an already overheated house. 

"Architectural shading" is simple, does not need any maintenance, and may reduce costs 

compared to sophisticated shading devices. Incorporating shading methods into the home during 

 

58 Sustainable Building Industries Council. Passive Solar Design Strategies: Guidelines for Home Building.

Sustainable Building Industries Council Website. www.psic.org
147 

the design phase ensures that a home receives the most effective shading. For example, providing 

properly designed overhangs shading the south glass adequately can reduce the heat gain during 

the summers while allowing for heat gain during the winters. Shading the west glass can also 

minimize the unwanted heat gains. A wide range of shading options is available, including the 

following: 

• Overhangs on South Sides. Extending the roofline a few feet can create shade for a home's 

south-facing windows. Because sun angles drop in the winter months, south-facing 

overhangs will let the warming sun into the home when it is needed. Because of low sun 

angles in summer mornings and afternoons, overhangs on the east or west have little to no 

affect. Shades for east- or west-facing windows must have some vertical dimension, such as 

awnings or shade screens. 

Decks and Porches. Adding a covered deck or porch is an excellent way to shade a home and to 

add living space, too. Porches and covered decks should have enough of an overhang to shield 

the area from the high sun and still offer a view outside from the interior spaces. 

• Awnings. Awnings provide excellent shading for south-, east-, and west-facing windows; 

awnings will block as much as 65% of the summer sun's heat (77% on an east- or west-facing 

window), but they have the disadvantage of blocking the top half of the view from the 

window and reducing ventilation when windows are opened. Retractable canvas awnings can 

overcome this problem to some extent because they can be extended only when they are 

needed. This is especially helpful in winter months, when occupants want to let the sun in to 

warm their home. 

• Louvers. Exterior louvers are attractive because their adjustable slats control the level of 

sunlight entering the building and, depending on the design, can be manually adjusted from 

inside or outside. The slats can be vertical or horizontal. Louvers remain fixed and are 

attached to the exteriors of window frames. Careful attention to the louver angle can allow 

significant winter sun penetration whilst still excluding all sun in summer. 

• Exterior Shade Screens. Retractable shade screens are a good choice for windows that 

receive direct sunlight. They work much like an inside window shade, except that they are 

attached to the outside of the window. Most shade screen manufacturers offer automatic 

controls for these products. The screens are installed at the top of the window and can be 

lowered during sunny days and retracted when not needed. Shade screens are generally 

custom-made. They are a good choice for a homeowner who wants to retrofit for energy 

efficiency but still wants to see out of a window that gets lots of sun throughout the day. The 

downside of shade screens is that they can darken the view when pulled down. 

Designing Shading Systems. The following design recommendations generally hold true for 

properly designed shading devices: 

• Use fixed overhangs on south-facing glass to control direct-beam solar radiation. Indirect 

(diffuse) radiation should be controlled by other measures, such as low-e glazing. 

• To the greatest extent possible, limit the amount of east and west glass because it is harder to 

shade than south glass. Consider the use of landscaping to shade east and west exposures, 

awnings, exterior shade screens, or interior highly reflective shades. 

• Do not worry about shading north-facing glass because it receives very little direct solar gain. 
148 

• Shading effects daylighting; consider both simultaneously. For example, a light shelf 

bounces natural light deeply into a room through high windows while shading lower 

windows. 

• Do not expect interior shading devices such as Venetian blinds or vertical louvers to reduce 

cooling loads because the solar gain has already been admitted into the work space. 

However, these interior devices do offer glare control and can contribute to visual acuity and 

visual comfort. 

• An understanding of sun angles is critical to selecting shading devices. 

• Carefully consider the durability of shading devices. Over time, operable shading devices can 

require a considerable amount of maintenance and repair. 

• When relying on landscape elements for shading, be sure to consider the cost of landscape 

maintenance and upkeep on life-cycle cost. 

• Shading strategies that work well at one latitude, may be completely inappropriate for other 

sites at different latitudes. Be careful when applying shading ideas from one project to 

another.
149 

Appendix B: Detailed BEopt Analysis Results 

Table B.1. BEopt Option Results for Single-Story Case 

CATEGORY BENCHMARK 35% POINT NEIGHBOR 1 NEIGHBOR 2 NEIGHBOR 3 NEIGHBOR 4 NEIGHBOR 5 

NE

Walls 

U = 0.085, 23% FF, R-11 batt, 2x4 16 in. oc + R-2.5 sheathing 

R-11, 2x4, 16 in. oc 

R-19, 2x6, 24 in. oc 

R-19, 2x6, 24 in. oc 

R-19, 2x6, 24 in. oc 

R-13, 2x4, 6 in. oc 

R-19, 2x6, 24 in. oc 

R-116 i

Ceiling U = 0.042, 11% FF, R-24 R-30 fiberglass R-30 fiberglass R-30 fiberglass R-30 fiberglass R-30 fiberglass R-30 fiberglass R-3Thermal Mass 

8 lbs/ft2 - 

furniture, standard light frame construction 

1⁄2-in. Ceiling Drywall 

1⁄2-in. Ceiling Drywall 

1⁄2-in. Ceiling Drywall 

Two 5/8-in. Ceiling Drywall Layers 

Two 5/8-in. Ceiling Drywall Layers 

Two 5/8-in. Ceiling Drywall Layers 

1/2-Dry

Infiltration SLA = 0.00057 SLA = 0.0005 SLA = 0.0005 SLA = 0.0005 SLA = 0.0005 SLA = 0.0005 SLA = 0.0005 SLA 

Slab Uninsulated Uninsulated Uninsulated Uninsulated Uninsulated Uninsulated Uninsulated UniGlass Type U = 0.79, SHGC = 0.65 

Two-pane Lowe, U = 0.3, SHGC = 0.44 Center of Glass, insulated spacer, Vinyl frame 

Two-pane Low-e, U = 0.29, SHGC = 0.29 Center of Glass, insulated spacer, Vinyl frame 

Heat Mirror, U = 0.18, SHGC = 0.48 Center of Glass, insulated spacer, Vinyl frame 

Two-pane clear, U = 0.49, SHGC = 0.76 Center of Glass, insulated spacer, Vinyl frame 

Two-pane Lowe, U = 0.32, SHGC = 0.64 Center of Glass, insulated spacer, Vinyl frame 

Two-pane Lowe, U = 0.32, SHGC = 0.64 Center of Glass, insulated spacer, Vinyl frame 

Twoe, U SHGCeninsuspaViny
150 

Table B.1 (continued). BEopt Option Results for Single-Story Case 

CATEGORY BENCHMARK 35% POINT NEIGHBOR 1 NEIGHBOR 2 NEIGHBOR 3 NEIGHBOR 4 NEIGHBOR 5 

NE

Window Area per Wall 

270 ft2, Equal 

distance on four sides 

270 ft2, 

12.5% N&S, 50% W, 25% E 

270 ft2, 

2.5% N&S, 50% W, 25% E 

270 ft2, 

12.5% N&S, 50% W, 25% E 

270 ft2, 

12.5% N&S, 50% W, 25% E 

270 ft2, 

12.5% N&S, 50% W, 25% E 

270 ft2, 

12.5% N&S, 50% W, 25% E 

270 

12.550% 

Refrigerator 669 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Standard - 671 kWh/yr Sta

kWh

Cooking Range 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 T

Dishwasher 

206 kWh/yr, 5-gal DHW/day 

Standard, 462 kWh, eight place setting capacity, 131.6 kWh/yr machine energy, 5.39-gal/day DHW 

Standard, 462 kWh, eight place setting capacity, 131.6 kWh/yr machine energy, 5.39-gal/day DHW 

Standard, 462 kWh, eight place setting capacity, 131.6 kWh/yr machine energy, 5.39-gal/day DHW 

Standard, 462 kWh, eight place setting capacity, 131.6 kWh/yr machine energy, 5.39-gal/day DHW 

Standard, 462 kWh, eight place setting capacity, 131.6 kWh/yr machine energy, 5.39-gal/day DHW 

Standard, 462 kWh, eight place setting capacity, 131.6 kWh/yr machine energy, 5.39-gal/day DHW 

StakWhplaccapkWhenegal/

Clothes Dryer 

Gas - 71.6kWh/yr, 31.3 Therms/yr 

Gas - 5.7 ft3, 2.75 

EF, 70.1 kWh/yr, 31.8 therms/yr 

Gas - 5.7 ft3, 2.75 

EF, 70.1 kWh/yr, 31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 70.1 kWh/yr, 31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 70.1 kWh/yr, 31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 70.1 kWh/yr, 31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 70.1 kWh/yr, 31.8 therms/yr 

Gas 

2.75 70.1 31.8 

Clothes Washer 

105 kWh/yr, 15 gal/day 

Standard, 3.15 ft3, 

533 kWh/yr, 1.16 MEF, 65.6 kWh/yr machine energy, 4.63-gal/day DHW 

Standard, 3.15 ft3, 533 kWh/yr, 

1.16 MEF, 65.6 kWh/yr machine energy, 4.63-gal/day DHW 

Standard, 3.15 ft3, 533 kWh/yr, 

1.16 MEF, 65.6 kWh/yr machine energy, 4.63-gal/day DHW 

Standard, 3.15 ft3, 533 kWh/yr, 

1.16 MEF, 65.6 kWh/yr machine energy, 4.63-gal/day DHW 

Standard, 3.15 ft3, 533 kWh/yr, 

1.16 MEF, 65.6 kWh/yr machine energy, 4.63-gal/day DHW 

Standard, 3.15 ft3, 533 kWh/yr, 

1.16 MEF, 65.6 kWh/yr machine energy, 4.63-gal/day DHW 

Staft3, 5

1.16 kWhenegal/
151 

Table B.1 (continued). BEopt Option Results for Single-Story Case 

CATEGORY BENCHMARK 35% POINT NEIGHBOR 1 NEIGHBOR 2 NEIGHBOR 3 NEIGHBOR 4 NEIGHBO

5 

Interior Lighting 

1574 kWh/yr Hardwired, 331 kWh/yr Plug in 

14% CFL, 1574 

kWh/yr Hardwired, 331 kWh/yr Plug in 

76% CFL, 749 kWh/yr Hardwired, 571 kWh/yr Plug in 

14% CFL, 1574 kWh/yr Hardwired, 331 kWh/yr Plug in 

14% CFL, 1574 kWh/yr Hardwired, 331 kWh/yr Plug in 

14% CFL, 1574 kWh/yr Hardwired, 331 kWh/yr Plug in 

14% CFL, 1574 kWh/yr Hardwired, 331 kWh/yPlug in 

Air Conditioner SEER 10, 0.55 W/CFM AH Fan SEER 10, 2.5 Tons, 0.365 W/CFM AH Fan SEER 12, 2.5 Tons, 0.365 W/CFM AH Fan SEER 10, 2.5 Tons, 0.365 W/CFM AH Fan SEER 12, 3 Tons, 0.365 W/CFM AH Fan SEER 10, 3 Tons, 0.365 W/CFM AH Fan SEER 10, 

Tons, 0.36W/CFM AH Fan 

Furnace 78% AFUE 80% AFUE, 50 kBtu/hr 80% AFUE, 75 kBtu/hr 80% AFUE, 50 kBtu/hr 80% AFUE, 75 kBtu/hr 80% AFUE, 75 kBtu/hr 80% AFUE

50 kBtu/hr 

Ducts 

100% Attic, 5% AH fan flow leakage to the outside 

Inside 

Conditioned Space, SA leakage = 1%, OA leakage = 0.23% of fan flow 

Typical, SA leakage = 10%, OA leakage = 5% of fan flow 

Inside Conditioned Space, SA leakage = 1%, OA leakage = 0.23% of fan flow 

Inside Conditioned Space, SA leakage = 1%, OA leakage = 0.23% of fan flow 

Inside Conditioned Space, SA leakage = 1%, OA leakage = 0.23% of fan flow 

Inside ConditioneSpace, SA leakage = 1%, OA leakage = 0.23% of fan flow 

Water Heater Gas, 40 gal, 0.54EF, 0.76RE Gas Standard, 40 gallons, 0.55 EF, 0.76 RE Gas Standard, 40 gallons, 0.55 EF, 0.76 RE Gas Standard, 40 gallons, 0.55 EF, 0.76 RE Gas Standard, 40 gallons, 0.55 EF, 0.76 RE Gas Standard, 40 gallons, 0.55 EF, 0.76 RE Gas Standard, 40 gallons, 0.55 EF, 0.76 RE 
152 

Table B.2. BEopt Energy and Savings Results for Single-Story Case 

 BENCHMARK 35% POINT NEIGHBOR 1 NEIGHBOR 2 NEIGHBOR 3 NEIGHBOR 4 NEIGHBOR 5 NEX

OP

Energy End Use (MBtu/yr) 

Misc. (E) 39.84 38.74 38.74 38.74 38.74 38.74 38.73 Lights (E) 16.13 16.13 8.99 16.13 16.13 16.13 16.13 

Heating Fan (E) 0.95 0.34 0.42 0.20 0.21 0.22 0.17 Cooling Fan (E) 22.44 7.21 9.24 7.08 7.86 7.94 7.76 Cooling (E) 108.95 54.67 55.46 53.33 51.21 60.49 58.87 Heating (G) 14.40 7.60 10.10 4.60 5.00 5.20 4.00 

Hot Water (G) 16.32 14.54 14.54 14.54 14.54 14.54 14.54 Misc. (G) 9.79 8.10 8.10 8.10 8.10 8.10 8.10 

Total 228.82 147.33 145.60 142.74 141.79 151.37 148.31 

End Use Savings 

Misc. (E) 2.8% 2.8% 2.7% 2.7% 2.8% 2.8% 

Lights (E) 0.0% 44.3% 0.0% 0.0% 0.0% 0.0% 

Heating Fan (E) 64.1% 55.2% 79.2% 77.5% 76.5% 82.4% 

Cooling Fan (E) 67.8% 58.8% 68.4% 65.0% 64.6% 65.4% 

Cooling (E) 49.8% 49.1% 51.0% 53.0% 44.5% 46.0% Heating (G) 47.2% 29.9% 68.1% 65.3% 63.9% 72.2% 

Hot Water (G) 10.9% 10.9% 10.9% 10.9% 10.9% 10.9% 

Misc. (G) 17.2% 17.2% 17.2% 17.2% 17.2% 17.2% 

Total Energy Savings 35.6% 36.4% 37.6% 38.0% 33.8% 35.2% 
153 

Table B.3. BEopt Option Results for Two-Story Case 

CATEGORY BENCHMARK 35% POINT NEIGHBOR 1 NEIGHBOR 2 NEIGHBOR 3 NEIGHBOR 4 NEIGHBOR 5 

N

Walls 

U = 0.085, 

23% FF, 

R11 batt, 2x4 

16 in. oc + 

R2.5 sheathing 

R19, 2x6, 

24 in. oc 

R19, 2x6, 

24 in. oc 

R19, 2x6, 

24 in. oc 

R19, 2x6, 

24 in. oc 

R13, 2x4, 

16 in. oc 

R13, 2x4, 

16 in. oc 

R

Ceiling U = 0.042, 11% FF, R-24 R-30 fiberglass R-30 fiberglass R-30 fiberglass R-30 fiberglass R-60 fiberglass R-30 fiberglass 

Thermal 

Mass 

8lbs/ft2 - 

furniture, 

standard light 

frame 

construction 

1⁄2-in. Ceiling 

Drywall 

1⁄2-in. Ceiling 

Drywall 

1⁄2-in. Ceiling 

Drywall 

1⁄2-in. Ceiling 

Drywall 

1⁄2-in. Ceiling 

Drywall 

1⁄2-in. Ceiling 

Drywall 

1⁄2

Infiltration SLA = 0.00057 SLA = 0.0005 SLA = 0.0005 SLA = 0.0003 SLA = 0.0005 SLA = 0.0005 SLA = 0.0005 S

Slab Uninsulated Uninsulated Uninsulated Uninsulated Uninsulated Uninsulated Uninsulated U

Glass Type U = 0.79, SHGC = 0.65 

Two-pane clear, 

U = 0.49, 

SHGC = 0.76 

Center of Glass, 

insulated 

spacer, Vinyl 

frame 

Two-pane 

clear, U = 0.49, 

SHGC = 0.76 

Center of 

Glass, 

insulated 

spacer, Vinyl 

frame 

Two-pane 

clear, U = 0.49, 

SHGC = 0.76 

Center of 

Glass, 

insulated 

spacer, Vinyl 

frame 

Two-pane clear, 

U = 0.49, 

SHGC = 0.76 

Center of Glass, 

insulated 

spacer, Vinyl 

frame 

Two-pane clear, 

U = 0.49, 

SHGC = 0.76 

Center of Glass, 

insulated 

spacer, Vinyl 

frame 

Two-pane Lowe, U = 0.32, 

SHGC = 0.64 

Center of Glass, 

insulated 

spacer, Vinyl 

frame 

S

s

Window 

Area per 

Wall 

540 ft2, Equal 

distANCE On 

four sides 

540 ft2, 

12.5% N&S, 

50% W, 25% E 

540 ft2, 

12.5% N&S, 

50% W, 25% E 

540 ft2, 

12.5% N&S, 

50% W, 25% E 

540 ft2, 

12.5% N&S, 

50% W, 25% E 

540 ft2, 

12.5% N&S, 

50% W, 25% E 

540 ft2, 

12.5% N&S, 

50% W, 25%E 

54

N

Refrigerator 669 kWh/yr 671 kWh/yr 671 kWh/yr 671 kWh/yr 671 kWh/yr 671 kWh/yr 671 kWh/yr 

Cooking 

Range 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 45 Therms/yr 4
154 

Table B.3 (continued). BEopt Option Results for Two-Story Case 

CATEGORY BENCHMARK 35% POINT NEIGHBOR 1 NEIGHBOR 2 NEIGHBOR 3 NEIGHBOR 4 NEIGHBOR 5 

N

Dishwasher 206 kWh/yr, 5 gal DHW/day 

Standard, 462 kWh, 8 place setting capacity, 131.6 kWh/yr machine energy, 5.39 gal/day DHW 

Standard, 462 kWh, eight place setting capacity, 131.6 kWh/yr machine energy, 5.39 gal/day DHW 

Standard, 462 kWh, eight place setting capacity, 131.6 kWh/yr machine energy, 5.39 gal/day DHW 

ENERGY STAR, 384 kWh, eight place setting capacity, 82.2 kWh/yr machine energy, 3.76 gal/day DHW 

Standard, 462 kWh, eight place setting capacity, 131.6 kWh/yr machine energy, 5.39 gal/day DHW 

Standard, 462 kWh, eight place setting capacity, 131.6 kWh/yr machine energy, 5.39 gal/day DHW 

StkWplcakWmenga

Clothes Dryer 

Gas - 71.6 kWh/yr, 31.3 Therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 70.1 kWh/yr, 31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 70.1 kWh/yr, 31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 70.1 kWh/yr, 31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 70.1 kWh/yr, 31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 70.1 kWh/yr, 31.8 therms/yr 

Gas - 5.7 ft3, 

2.75 EF, 70.1 kWh/yr, 31.8 therms/yr 

G

2.kWth

Clothes Washer 

105 kWh/yr, 15 gal/day 

Standard, 3.15 ft2, 533 kWh/yr, 

1.16 MEF, 65.6 kWh/yr machine energy, 4.63 gal/day DHW 

Standard, 3.15 ft3, 533 kWh/yr, 

1.16 MEF, 65.6 kWh/yr machine energy, 4.63 gal/day DHW 

Standard, 3.15 ft3, 533 kWh/yr, 

1.16 MEF, 65.6 kWh/yr machine energy, 4.63 gal/day DHW 

Standard, 3.15 ft3, 533 kWh/yr, 

1.16 MEF, 65.6 kWh/yr machine energy, 4.63 gal/day DHW 

Standard, 3.15 ft3, 533 kWh/yr, 

1.16 MEF, 65.6 kWh/yr machine energy, 4.63 gal/day DHW 

Standard, 3.15 ft3, 533 kWh/yr, 

1.16 MEF, 65.6 kWh/yr machine energy, 4.63 gal/day DHW 

Stft3

1.65menga

Interior Lighting 

14% CFL, 2284 kWh/yr Hardwired, 571 kWh/yr Plug in 

14% CFL, 2534 kWh/yr Hardwired, 571 kWh/yr Plug in 

14% CFL, 2534 kWh/yr Hardwired, 571 kWh/yr Plug in 

14% CFL, 2534 kWh/yr Hardwired, 571 kWh/yr Plug in 

14% CFL, 2534 kWh/yr Hardwired, 571 kWh/yr Plug in 

14% CFL, 2534 kWh/yr Hardwired, 571 kWh/yr Plug in 

14% CFL, 2534 kWh/yr Hardwired, 571 kWh/yr Plug in 

14kWHkW

Air Conditioner 

SEER 10, 0.55 W/CFM AH Fan 

SEER 12, 4.00 Tons, 0.365 W/CFM AH Fan 

SEER 12, 4.00 Tons, 0.365 W/CFM AH Fan 

SEER 12, 4.00 Tons, 0.365 W/CFM AH Fan 

SEER 13, 4.00 Tons, 0.365 W/CFM AH Fan 

SEER 12, 4.00 Tons, 0.365 W/CFM AH Fan 

SEER 12, 4.00 Tons, 0.365 W/CFM AH Fan 

SToWFa

Furnace 78% AFUE 80% AFUE, 100 kBtu/hr 80% AFUE, 100 kBtu/hr 80% AFUE, 100 kBtu/hr 80% AFUE, 100 kBtu/hr 80% AFUE, 125 kBtu/hr 80% AFUE, 100 kBtu/hr 80

10
155 

Table B.3 (continued). BEopt Option Results for Two-Story Case 

CATEGORY BENCHMARK 35% POINT NEIGHBOR 1 NEIGHBOR 2 NEIGHBOR 3 NEIGHBOR 4 NEIGHBOR 5 

N

Ducts 

65% Attic, 35% Conditioned Space, 1.5% AH fan flow leakage to the outside 

Inside Conditioned Space, SA leakage = 1%, OA leakage = 0.23% of fan flow 

Inside Conditioned Space, SA leakage = 1%, OA leakage = 0.23% of fan flow 

Inside Conditioned Space, SA leakage = 1%, OA leakage = 0.23% of fan flow 

Inside Conditioned Space, SA leakage = 1%, OA leakage = 0.23% of fan flow 

Inside Conditioned Space, SA leakage = 1%, OA leakage = 0.23% of fan flow 

Inside Conditioned Space, SA leakage = 1%, OA leakage = 0.23% of fan flow 

InCSleO0.flo

Water Heater 

Gas, 40 gal, 0.54 EF, 0.76 RE 

Gas Standard, 40 gallons, 0.55 EF, 0.76RE 

Gas Tankless, 0.84 EF 

Gas Standard, 40 gallons, 0.55 EF, 0.76 RE 

Gas Standard, 40 gallons, 0.55 EF, 0.76 RE 

Gas Standard, 40 gallons, 0.55 EF, 0.76 RE 

Gas Standard, 40 gallons, 0.55 EF, 0.76 RE 

G40 0.R
156 

Table B.4. BEopt Energy and Savings Results for Two-Story Case 

CATEGORY BENCHMARK 35% POINT NEIGHBOR 1 NEIGHBOR 2 NEIGHBOR 3 NEIGHBOR 4 NEIGHBOR 5 NEXT P

C

Energy End Use (MBtu/yr) Misc. (E) 67.94 66.84 66.84 66.84 66.33 66.84 66.83 

Lights (E) 25.98 25.98 25.98 25.98 25.98 25.98 25.98 Heating Fan (E) 1.55 0.44 0.44 0.26 0.44 0.52 0.46 Cooling Fan (E) 36.84 14.43 14.43 13.95 14.12 14.54 13.54 Cooling (E) 185.20 97.13 97.13 93.23 90.68 98.17 90.82 Heating (G) 24.00 10.30 10.30 6.40 10.30 12.00 10.60 Hot Water (G) 16.32 14.54 8.25 14.54 14.24 14.54 14.54 Misc. (G) 9.79 8.10 8.10 8.10 8.10 8.10 8.10 

Total 367.62 237.76 231.47 229.31 230.19 240.69 230.88 
157 

Table B.4 (continued). BEopt Energy and Savings Results for Two-Story Case 

CATEGORY BENCHMARK 35% POINT NEIGHBOR 1 NEIGHBOR 2 NEIGHBOR 3 NEIGHBOR 4 NEIGHBOR 5 NEXT PO

C

End Use Savings 

Misc. (E) 1.6% 1.6% 1.6% 2.4% 1.6% 1.6% 

Lights (E) 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0Heating Fan (E) 71.5% 71.5% 83.1% 71.6% 66.7% 70.2% 7

Cooling Fan (E) 60.8% 60.8% 62.1% 61.7% 60.5% 63.3% 6

Cooling (E) 47.6% 47.6% 49.7% 51.0% 47.0% 51.0% 5

Heating (G) 57.1% 57.1% 73.3% 57.1% 50.0% 55.8% 5

Hot Water (G) 10.9% 49.5% 10.9% 12.8% 10.9% 10.9% 1

Misc. (G) 17.2% 17.2% 17.2% 17.2% 17.2% 17.2% 1

Total Energy Savings 35.3% 37.0% 37.6% 37.4% 34.5% 37.2% 3
158 

BEopt Cost and Performance Input Assumptions 

As with any analysis study, the results of the analysis are subject to the assumptions used 

during the study. The cost and performance assumptions used in the present study are 

documented in this Appendix. These assumptions will be updated on a regular basis as new 

information becomes available from residential field studies. The use of specific manufacturer 

names in this Appendix does not represent an endorsement or recommendation for use of a 

specific product. This Appendix is limited to categories that include multiple options specific 

to the optimizations performed and may not representative of all the possible options currently 

available within BEopt. 

Table B.5. Utility and Onsite Power Inputs 

Group Input Variable Value Units 

Economics 

Electricity Source/Site 

Ratio 3 

 Electricity Cost 0.0778 $/kWh 

Natural Gas Cost 0.7986 $/therm 

 Discount Rate 0.05 

Mortgage Interest Rate 0.07 

Marginal Income Tax Rate 0.28 

 Analysis Period 30 years 

Net Metered Excess Sellback 

Rate Local electric rate $/kWh 

Efficiency Cost Multiplier 1 

Photovoltaics Module Sharp NEH120E1 

 Installed Cost 

7.5 (unless noted 

otherwise) $/rated W 

Derate Factor Determined by location % 

Daily Incident Solar Determined by location kWh/m2

Average System Efficiency Determined by location % 
159 

Table B.6. BEopt Cost Assumptions 

CATEGORY/OPTION UNIT COST 

Slab ($/ft) 

Uninsulated $0.00 

2-ft R5 Perimeter, R-5 Gap $1.38 

4-ft R5 Perimeter, R-5 Gap $2.36 

2-ft R10 Perimeter, R-5 Gap $2.22 

4-ft R10 Perimeter, R-5 Gap $3.92 

15-ft R10 Perimeter, R-5 Gap $8.19 

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 

Thermal Mass ($/ft2

) 

Standard 1⁄2-in. Ceiling Drywall $0.19 
160 

Table B.6 (continued). BEopt Cost Assumptions 

CATEGORY/OPTION UNIT COST 

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 

Refrigerator ($/unit) 

Standard - 671 kWh/yr $1,099.99 

ENERGY STAR - 572kWh/yr $1,219.99 
161 

Table B.6 (continued). BEopt Cost Assumptions 

CATEGORY/OPTION UNIT COST 

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, eight place setting capacity, 

82.2 kWh/yr machine energy, 3.76 gal/day DHW $299.00 

Clothes Washer ($/unit) 

Standard, 3.15 ft3

, 533 kWh/yr, 1.16 MEF, 

65.6 kWh/yr machine energy, 4.63 gal/day DHW $419.00 

ENERGY STAR, top loader, H-axis, 2.9 ft3

, 273 kWh/yr, 

1.68 MEF, 72.9 kWh/yr machine energy, 3.71 gal/day 

DHW $799.00 

Lighting ($/bulb) 

Incandescent $0.25 

CFL $7.99 

Air Conditioner SEER value 

Efficiency Cost ($) = 

0.817*((186*SEERvalue)-1535)

10 $265.53 

12 $569.45 

13 $721.41 

14 $873.37 

15 $1,025.34 

16 $1,177.30 

17 $1,329.26 

18 $1,481.22 
162 

Table B.6 (continued). BEopt Cost Assumptions 

CATEGORY/OPTION UNIT COST 

Air Conditioner Capacity (tons) 

Capacity Cost ($) = 

0.817*(563*tons) 

0.5 $229.99 

1.0 $459.97 

1.5 $689.96 

2.0 $919.94 

2.5 $1,149.93 

3.0 $1,379.91 

3.5 $1,609.90 

4.0 $1,839.88 

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 

200 kBtu/hr 

$511.00 

$584.00 
163 

Table B.6 (continued). BEopt Cost Assumptions 

CATEGORY/OPTION UNIT COST 

Water Heater ($/unit, install + equip) 

Gas Standard, 40 gallons, 0.55 EF $428.00 

Gas Premium, 40 gallon , 0.62EF $624.08 

Gas Tankless, 0.84 EF $1,050.00 

Ducts ($/ft2

 FFA) 

Typical, SA leakage = 10%, 

OA leakage = 2.3% of fan flow $0.45 

Improved, SA leakage = 2.3%, 

OA leakage = 0.5% of fan flow $0.69 

Inside Conditioned Space, SA leakage = 1%, 

OA leakage = 0.23% of fan flow $0.77 
164 

Appendix C: List of Key Trade-based Certifications 

Preferred Contractors Program Draft 

Below is a preliminary list of the different trade classifications and the sub-specializations that 

could be associated with a new-home certified-contractors program. The concept is to have a 

broad range of specialist classifications, to acknowledge the fragmentation and specialization 

that is inherent in the construction industry. This encourages even those trades who do a very 

limited scope of work (i.e., just window installation or just duct rough in) to become certified 

specialists in their field, which requires them to also have a broader understanding of how that 

piece fits into the bigger house as a system. This concept will need to be discussed with 

manufacturers and trade contractors to determine its practicality. 

1. HVAC 

a. Space-Conditioning System Design Specialist 

b. Duct Design Specialist 

c. Air-Distribution System Installation Specialist 

d. Equipment Installation and Start-up Specialist 

i. Fossil and electric heating 

ii. Refrigeration – AC / Heat Pump 

e. Airflow Balancing Specialist 

2. Carpentry 

a. Framing Specialist 

3. Thermal envelope 

a. Insulation Specialist 

b. Air-sealing Specialist 

4. Above-grade moisture management 

a. Window and Door Installation Specialist 

b. Wall Drainage Plane Specialist 

c. Roof Drainage and Flashing Specialist 

5. Below-grade moisture management 

a. Below-Grade Moisture Management Specialist 

6. Designers 

a. Architect / Residential Designer 

b. Engineer 
165 

Within each of the specializations is a more detailed description of the probable roles and 

competencies required. 

1. HVAC 

a. Space-Conditioning System Design Specialist 

i. Load Calculation, Ventilation, and Equipment-Selection Specialist 

1. Proficiency in ACCA Manual J method for load calculation and how to 

account for higher performance when calculating heating and cooling 

loads 

2. 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 

3. Surface area competencies and understanding of thermal envelope 

assemblies (i.e., framing factors, window properties, etc.) 

4. Understands the types of ventilation systems and their interaction with 

the heating and cooling equipment 

5. Understands dedicated humidity control options and how to integrate 

with space-conditioning systems 

6. Understands the internal gains and latent loads associated with people 

and ventilation 

7. Understands the impact of climate, shading, and other environmental 

impacts on the building. 

ii. Duct Design Specialist 

1. Understands the impact of duct friction with respect to airflows 

(equivalent length methods – ACCA Manual D) 

2. Familiarity with structural systems and limitations regarding using 

running duct systems within structural systems (floor-framing systems, 

walls, etc.) 

3. Air distribution options in higher performance homes (high sidewall, 

central return, etc.) 

4. Acoustics of air distribution systems 

b. Air-Distribution System Installation Specialist 

i. Follows layout by Duct-Design Specialist 

ii. Understands duct-sealing techniques 

iii. Understands ventilation system concepts as they relate to ducts and 

equipment installation issues 

iv. Certified in duct-system leakage testing 

v. Sets furnace and inside AC coils as part of air system 
166 

c. Equipment Installation and Start-up Specialists 

i. Installation of equipment and associated refrigeration 

ii. Start-up and commissioning of heating, cooling and ventilation systems 

d. Airflow Balancing Specialist 

i. Airflow at the equipment 

ii. Total system duct leakage testing 

iii. Room-by-room airflow balancing and measurement 

2. Carpentry 

a. Framing Specialist 

i. Optimum value engineering of wood frame structures 

1. Stack framing 

2. Wall layout and value engineering wall-framing techniques 

3. Floor framing and interaction with HVAC system and plumbing system 

4. Structural and code limitations 

ii. Air-sealing techniques incorporated during framing (i.e., band joist gluing 

and sealing, mud sill sealing, cantilevers, floors over garages, chases, etc.) 

3. Thermal envelope 

a. Insulation Specialist 

i. Insulation basics 

1. How insulation works 

2. Encapsulation requirements 

3. Types of insulation products, limitations, and applications 

4. Insulation and flame spread issues 

ii. Blown-in wall techniques (new and retrofit) 

1. Damp spray 

2. Net and fill cavity 

3. Two-hole method 

4. Hole and tube (dense pack) 

iii. Blown attic and horizontal cavity (floor, cantilever, etc.) 

iv. Batt installation 

v. Below-grade insulation systems (interior) 

vi. Crawlspace vapor barrier installation 

vii. Sub-Specialist designation 
167 

b. Air-Sealing Specialist 

viii. Envelope air-tightening techniques 

ix. Window and door rough openings 

x. Framing intersections 

xi. Bypasses / chases / soffits 

xii. Cantilevers, floors over unconditioned spaces 

xiii. Fire codes and safety 

xiv. Diagnostics 

xv. Blower door 

1. Pre- and post-testing 

2. Blower door directed air-sealing techniques 

xvi. Infrared imaging 

xvii. Pressure diagnostics 

4. Above-grade moisture management 

a. Window and Door Installation Specialist 

i. Flashings 

ii. Integration to drainage plane 

b. Wall Drainage Plane Specialist 

i. Drainage plane installation 

ii. Integration with windows and doors 

iii. Integration with roof flashing systems 

iv. Roof-flashing systems at wall intersections 

c. Roof Drainage and Flashing Specialist 

i. Roof-penetration flashings 

ii. Roof wallflashing systems 

iii. Integration to wall systems 

iv. Gutter and downspouts 

5. Below-grade moisture management 

a. Below-Grade Moisture Management Specialist 

i. Perimeter drainage systems 

ii. Sub-slab capillary break and vapor diffusion control 

iii. Capillary break at footing 

iv. Vapor barrier at crawlspaces 

v. Foundation damp-proofing systems 

vi. Foundation waterproofing systems 
168 

6. Designers 

a. Architect / Residential Designer 

b. Engineer 
169 

Appendix D: National Housing Quality Rating Table 

Table D.1. Leadership Leaders align everyone in the organization with a common purpose, values, and priorities. 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

1.1 Company Mission, Vision, and Values 

Company's main quality goal is to avoid customer disappointment and complaints. 

Quality and customer satisfaction is important to the company but not included in a written mission statement. 

Written company mission statement includes a commitment to quality and customer satisfaction. 

Quality is defined in the five key performance metrics (Health, Safety, Durability, Efficiency & Comfort) with measurable attributes associated with the definition. 

In addition to level 3, values or principles important to the company are included in a written statement. 

PoBtei

1.2 Senior Management Involvement 

Senior managers get involved with quality to handle customer complaints. 

Senior managers like the idea of quality but are not involved in improvement activities. 

Senior managers demonstrate personal commitment to the company's quality mission and are often involved in qualityrelated activities 

Performance attributes are given equal weight to other quality criteria. Quality Management is a cross-cutting management function 

Senior managers constantly communicate the company's quality mission to customers, employees, and trade contractors. 

OfpodwStp

1.3 Leadership Feedback and Improvement 

Senior management uses their experience to guide the company toward their vision for the future. 

Senior managers actively seek employee feedback to gauge the organization’s alignment toward the company mission, vision, and values. 

In addition to level 2, surveys measure the alignment of employee values and beliefs toward those of the organization. 

Performance metrics are included in survey 

In addition to level 3, senior managers plan initiatives to reinforce the company mission, vision, and values. 

Pai
170 

Table D.1. Leadership (continued) 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

1.4 Living the Mission 

Employees may have different priorities but there is a general understanding of what the company is trying to accomplish. 

Most employees know key elements of the company mission, values, and vision for the future and could explain how it relates to their job. 

Most employees recognize and support organizational mission, values, and vision, and use them to guide their decision making. 

Performance metrics are instilled as one component that is used in decision making 

In addition to level 3, survey data shows that most employees embrace the company mission, vision, and values. There is a strong feeling that everyone is working toward common goals. 

Spaeuipa

1.5 Public Responsibility 

Some people at the company are personally involved in activities that benefit the community, the public, or the housing industry. 

When asked, the company supports activities to benefit the community, the public, or the housing industry. 

Being a responsible corporate citizen is regarded as good for the company. The company is actively involved in activities to benefit the community, the public, or the housing industry. 

Company involvement is related to performance metrics 

In addition to level 3, the company creates opportunities to be actively involved in activities to benefit the community, the public, or the housing industry. 

Cap

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set.
171 

Table D.2. Strategic Planning Achieving a future vision of what the company can become requires creating and executing a strategic plan for getting there. 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 IB

2.1 Company-wide Success Drivers and Performance Measures. 

Measures of company performance are limited to sales and profit. 

In addition to level 1, customer satisfaction is important, but performance data is not tracked. 

The current customer satisfaction rating is one of the company’s monthly performance measures communicated to all employees. 

Customer satisfaction measurements include consumer feedback on performance metrics, and limited testing to verify performance metrics are being achieved 

In addition to level 3, company-wide performance measures link directly to key success drivers for achieving the company mission and vision. 

Lssspp

2.2 Strategic Plans 

Company improvement strategy is to increase sales and reduce costs, but specific action plans are not in place. 

The company's competitive business strategy includes improving customer satisfaction and products that enhance homeowner value. 

In addition to level 2, written improvement plans are in place with measurable goals. Plans explain how performance improvement goals will be achieved. 

Written improvement plans include performance standards and testing requirements. Plan outlines cross functional leader for performance-based quality initiative 

In addition to level 3, strategic plans link directly to improvement of company-wide performance measures and fully support the company's mission and values. 

Pminc

2.3 Plan Deployment 

The senior managers who make the strategic plans also carry out the improvement initiatives. Employees are involved on an asneeded basis. 

Senior managers develop the strategic plan with some employee input. The plan is used to set departmental objectives. 

In addition to level 2, senior managers organize employee teams to carry out improvement projects that may involve multiple departments. 

A systematic process is in place for involving most employees in the development of strategic objectives, carrying out action plans to achieve them, and monitoring progress. 

Minpsuthwla

2.4 Monitoring Progress to Plan 

Progress is monitored on an as-needed basis. 

Quarterly review meetings monitor improvement progress. 

Monthly review meetings monitor actual versus planned improvement activities. Adjustments to plans are made to accommodate current status. 

Measurements of key performance attributes are made to judge achievement of goals 

In addition to level 3, measurement data is used to monitor performance toward strategic objectives. 

Tfuecim

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set.
172 

Table D.3. Customer Satisfaction Sustaining high levels of customer satisfaction requires performing well from the customer’s point of view. 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 IB

3.1a Market Research 

Market requirements are learned mainly from customer requests. 

In addition to level 1, market trends are learned from tours of other builders' products and builder magazines. 

In addition to level 2, detailed price and feature comparisons with other builders are used to analyze competitive position and uncover unfilled market niches. Feedback from lost customers is used to analyze unfilled needs. 

Product is Benchmarked compared to national and local standards. Feedback strategies also capture data regarding performance attributes 

In addition to level 3, markets are analyzed by demographic groups. Surveys or focus groups identify customer preferences for features and services. 

Finkfea5p

3.1b Product Design Processes 

A company expert or consultants create new home designs. 

In addition to level 1, select employees provide some input into the design process. 

A new home design team includes construction and sales personnel. 

In addition to level 3, homeowners, employees, and trade contractors are systematically included in the home design process. 

Pspuinpa p

3.2 Customer Satisfaction Drivers 

Avoiding homeowner disappointment with the constructed product is the main customer satisfaction priority. 

Completing the home on time with a short punch list at final inspection is the company’s main focus for satisfying customers. 

In addition to level 2, the customer experience and relationship with the builder are important customer satisfaction drivers. Meeting customer expectations is recognized as the key to reliably satisfying customers. 

Builder monitors expectation set by other builders, and seeks to set similar consumer expectations through sales process 

Exceeding customer expectations is an important company priority. Employees understand how their team and department performance contributes to overall customer satisfaction. 

Bctsma
173 

Table D.3. Customer Satisfaction (continued) 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 IB

3.3 Customer Relationship Management 

Maintaining good customer relationships through final inspection is the main priority. Everyone has his or her own way of working with customers, with varying degrees of effectiveness. 

Maintaining good customer relationships through the end of the warranty period is the main priority. Policies for dealing with customers are in place for the sales process. 

Relationships with customers are recognized as a key customer satisfaction driver. A process is in place for creating positive customer relationships in sales, construction, and service phases. 

In addition to level 3, customer expectations for key customer satisfaction drivers are systematically managed throughout the customer relationship. Customers are viewed as customers for life. 

Kins

3.4a Customer Satisfaction Measurement 

Customer satisfaction feedback data consists of final inspection punch lists and warranty callbacks. 

Customer satisfaction is measured occasionally by surveys or by asking customers. Some questions ask customers to rate employee performance. 

All customers are surveyed on their satisfaction with the home and the customer experience during the sales, construction, and warranty service periods. Questions focus on process performance rather than employee ratings. 

Survey links expectations of housing performance compared to actual experience of living in home (i.e., comfort, energy performance, durability, noise, etc.) 

In addition to level 3, customer satisfaction survey questions are directly linked to known customer satisfaction drivers. 

Mcinkd

3.4b Sharing of Customer Satisfaction Feedback 

Customer complaints are shared with the persons responsible. 

Customer letters and surveys are routinely circulated among employees. 

In addition to level 2, Summary customer satisfaction data is available to all employees. Trends are tracked and posted for all to see. Senior managers frequently discuss customer feedback with employees. 

Customer satisfaction ratings are routinely communicated to the organization as one of the company-wide performance measures. Relevant customer satisfaction data is shared with suppliers and trade contractors. 

Pins
174 

Table D.3. Customer Satisfaction (continued) 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

3.5 Customer Satisfaction Results 

Percentage of customers who would recommend the company to a friend is not measured. 

More than 75% of customers surveyed would recommend the company to a friend. Customer satisfaction seems to be improving. 

More than 85% of customers surveyed would recommend the company to a friend. There are measured improvements in customer satisfaction. 

More than 85% of customers surveyed feel home meets the company standard of performance 

More than 90% of customers surveyed would recommend the company to a friend. Customer satisfaction shows measured improvements in most products and services. 

Mcfecp

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set. 
175 

Table D.4. Performance Management 

 Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

4.1a Creating HighPerformance Work Processes 

Meeting minimum performance expectations is an important priority for most employees. 

Most employees have well-defined responsibilities. Finding ways to reduce costs is the main focus of work improvement activities. 

Key work processes are well defined. Customer satisfaction and cost are important work improvement priorities. 

“Building performance quality management” has been identified as a key work process, and has been assigned within the organization 

Customer needs drive work systems design and improvements. Some work systems are modeled on industry best practices. 

Tpm

4.1b Bench-Marking Business Processes 

Information on how other builders do things is obtained mostly from publications and seminars. 

Occasional visits to other builders are made to get some good ideas. 

Regular visits to other builders are made to compare performance results and set improvement objectives. 

Those builders visited include others who are improving building performance at Level 3 and at least one at Level 4 

In addition to level 3, detailed studies of other builders’ operations are used to design operational improvements. 

TinimpaL

4.2 Performance Management 

Performance is managed by monitoring the productivity of individual employees. 

In addition to level 1, conformance to department budgets is used to manage financial performance. 

Performance management focuses on the productivity of key business processes. Results are tracked and reviewed monthly. 

Building to a predefined performance standard is identified as a key business process 

In addition to level 3, key work processes have performance measures that link directly to companywide key success measures. Results are shared with all employees. 

Pau

4.3 Process Improvement 

Problems are handled as they occur to avoid customer complaints. 

Changes to company processes are made occasionally to prevent recurring problems. Some employees are involved in improvement projects. 

Improving company processes is an important part of everyone’s job. There are many improvements made throughout the company. The company uses a systematic method to make improvements. 

Process of designing and building for performance is identified as a key process improvement area 

An effective strategy and goals are in place for involving the entire workforce in problem solving and quality improvement. Most employees have been trained in the company’s process improvement methods. 

Qmwcp
176 

Table D.4. Performance Management (continued) Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set. 

 Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 IB

4.4 Improvement Results 

Some company work processes seem to be improving, but there are no measures of progress. 

Some company work processes show measured quality improvements. 

Most company work 

processes show measured quality improvements. 

Most company work processes show measured quality improvements and excellent quality results. 

Pam

4.5 Financial Improvement Results 

Some improvements have resulted in cost reductions. 

Substantial cost reductions have been made but have not yet helped improve home sales. 

Home sales and company profitability show improvement. 

Profitability is in some way attributable to performance standards (reduction in callbacks, improved value, etc.) 

Company's share of home sales is increasing. Company profitability shows excellent results with positive trends. 

Mmcpcto p
177 

Table D.5. Human Resources The human resources system must develop the full potential of employees and drive the right behaviors in support of company performance and learni

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

5.1a Employee Satisfaction 

The company shows a general concern for employee well-being and morale. 

Company shows that employee well-being and morale are priorities in making business decisions. There are occasional morale-building activities. 

In addition to level 2, employee satisfaction is recognized as important for the company’s success. Senior managers take initiatives to do what they think will improve the work environment. 

The company understands which factors drive employee satisfaction. Employee surveys measure employee satisfaction and the information is used to improve the work environment. 

Rpamce

5.1b Jobsite Safety 

There are occasional safety-related training activities. 

Health and safety training is provided to all field employees. 

Company shows that employee health and safety are priorities in making business decisions. 

In addition to level 3, there is an organized approach to analyzing causes of injuries and preventing accidents. 

5.1c Job Responsibilities 

Employees learn job responsibilities from on-the-job experience. 

Job descriptions define job responsibilities. 

In addition to level 2, most employees clearly understand their job responsibilities and how their job contributes to company performance. 

Job Responsibilities are also tied to Building Performance 

In addition to level 3, employees feel responsible for performing their job to meet the needs of other employees who depend on them. 

Orpsa

5.1d Teamwork 

Individual effort is the main way things get done. 

Some natural work groups are formed into operating teams with shared responsibilities. 

Most employees are part of an operating team with a wellunderstood purpose. Teams are the main way that day-to-day work gets done. 

Performance attributes and standards are part of the purpose within a team 

In addition to level 3, teamwork is the primary mechanism for solving problems and making performance improvements. 

Pibsi
178 

Table D.5. Human Resources (continued) 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 I

5.2 Workforce Development 

Skills are learned on the job. 

Work-related training is delivered as needed when time and budget allows. 

There is a company training budget. Most employees receive some training. Most employees have personal training and development plans. 

Key general training on issues related to building-performance standards is provided and specifically related to company performance standards 

In addition to level 3, the company’s training and hiring plan is aimed at developing the skills necessary for achieving the longrange company vision. 

Tpsef

5.3 Employee Evaluation and Compensation Systems 

Most employees receive an annual performance review. 

Annual employee performance reviews have well-defined evaluation criteria. Bonuses and recognition reward individual efforts. 

In addition to level 2, employee performance evaluation criteria are linked to job descriptions. Bonuses focus on team efforts. 

Evaluation criteria include measurement of achievement of building-performance standards 

Employee performance evaluation criteria are based on fulfillment of personal development plans and key elements of the company mission, vision, and values. 

Bst

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set.
179 

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
180 

Table D.6. Quality Construction Processes (continued) 

Level 1 Level 2 Level 3 IBACOS Level 3 Level 4 IB

6.4 Warranty Service 

Service callbacks are handled but not tracked. 

Systems are in place to track warranty complaints and their completion. 

In addition to level 2, warranty service data is used to set priorities for solving quality problems. 

Warrantee service data is broken down to capture root causes 

In addition to level 3, response time and customer satisfaction with each service call are important performance measures. 

Kdtrto cc

6.5 Product and Service Quality Results 

Product and service quality seems to be improving, but there are no measures of progress. 

Problems found at final inspection are decreasing. There are fewer callbacks. 

Data shows that constructed quality is improving. 

Quality is defined according to building science based performance metrics 

Most product and service quality performance indicators show excellent results with positive trends. Zero defect final inspections are commonplace. 

Dmsmate

Note: Yellow denotes minimum level for considering adopting a 30% whole-house energy-savings solution set.
181 

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

7.1 Trade Contractor and Supplier Relationships 

Difficult quality problems are usually solved by changing contractors or suppliers. 

A systematic process is in place for the selection of trade contractors. Trades and suppliers participate in solving problems. 

Key trade contractors and suppliers are considered partners. Company helps them improve quality and reduce costs. 

Performance standards are a metric of quality, testing measures improvement 

In addition to level 3, most major trade contractors and suppliers participate in a systematic approach to problem-solving and quality improvement. 

Cinpto cbspp

7.2 Trade Development 

There are no formal initiatives to develop the capabilities of trade contractors. 

Improving trades is focused on solving problems. 

A general strategy is in place to develop the capabilities and performance of trade contractors. 

Builder provides general training on Performance standards and trades relation to standards 

The company’s trade development plans are linked directly to achieving the company’s long-range vision. 

Tusinathpa

7.3 Trade Contractor Performance Management 

Trade performance is evaluated when problems arise or when contracts are renewed. 

Trade performance data consists of inspection punch lists and callbacks, but trend data is not tracked. 

Trade performance trend data is tracked and reviewed regularly with the key trades and used to improve quality and prevent defects. 

Primary use is checklists, some performance test data used to gauge trade against performance standards 

Customer satisfaction survey data on construction workmanship is used as a trade performance indicator. 

Pufo

7.4 Trade Contractor and Supplier Results 

Trade contractor quality seems to be improving, but there are no measures of progress. 

Some trade contractors show measured quality improvements. 

All major trade contractors show measured quality improvements. 

Measurement system includes key performance attributes 

All major contractors show excellent quality results. Most trade contractors routinely meet quality standards. 

Qins
182

Appendix E. National Housing Quality Survey 

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? 
183

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? 
184

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? 
185 

Appendix F. SNAPSHOT Form 
F1147-E(12/2004) 

REPORT DOCUMENTATION PAGE Form Approved 

OMB No. 0704-0188

The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, 

gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this 

collection of information, including suggestions for reducing the burden, to Department of Defense, Executive Services and Communications Directorate (0704-0188). Respondents 

should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a 

currently valid OMB control number. 

PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION.

1. REPORT DATE (DD-MM-YYYY)

January 2006 

2. REPORT TYPE

Subcontract Report 

3. DATES COVERED (From - To)

January 2005 – November 2005 

4. TITLE AND SUBTITLE

Building America Residential System Research Results: Achieving 

30% Whole House Energy Savings Level in Hot-Dry and Mixed-Dry 

Climates 

5a. CONTRACT NUMBER

DE-AC36-99-GO10337 

5b. GRANT NUMBER

5c. PROGRAM ELEMENT NUMBER

6. AUTHOR(S)

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) 

5d. PROJECT NUMBER

NREL/SR-550-38201 

5e. TASK NUMBER

BET6.8004 

5f. WORK UNIT NUMBER

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES)

National Renewable Energy Laboratory 

1617 Cole Blvd. 

Golden, CO 80401-3393 

8. PERFORMING ORGANIZATION 

REPORT NUMBER

NREL/SR-550-38201 

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES) 10. SPONSOR/MONITOR'S ACRONYM(S)

NREL 

11. SPONSORING/MONITORING 

AGENCY REPORT NUMBER

12. DISTRIBUTION AVAILABILITY STATEMENT

National Technical Information Service 

U.S. Department of Commerce 

5285 Port Royal Road 

Springfield, VA 22161 

13. SUPPLEMENTARY NOTES

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 Hot-Dry / Mixed-Dry Climate Region on a 

cost neutral basis. 

15. SUBJECT TERMS

Building America; U.S. Department of Energy; systems research; Hot-Dry Mixed-Dry Climates; 30% energy savings 

level; energy efficient housing 

16. SECURITY CLASSIFICATION OF: 17. LIMITATION 

OF ABSTRACT

UL 

18. NUMBER 

OF PAGES 

19a. NAME OF RESPONSIBLE PERSON 

a. REPORT 

Unclassified 

b. ABSTRACT 

Unclassified

c. THIS PAGE 

Unclassified 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.

January 2006 • NREL/SR-550-38201

Printed with a renewable-source ink on paper containing at least 50% wastepaper, including 10% postconsumer waste.

Visit our Web sites at:

www.buildingamerica.gov www.pathnet.org www.energystar.gov