The 2002 NREL Denver Habitat for Humanity House, 

April 2005 • NREL/TP-550-36150 

Affordable High-Performance Homes: 

A Cold-Climate Case Study

A Project of the U.S. Department of Energy’s Building America Program 

Paul Norton, National Renewable Energy Laboratory 

Byron Stafford, National Renewable Energy Laboratory 

Bruce Carpenter, Habitat for Humanity, Denver, Colorado 

C. Edward Hancock and Greg Barker, Mountain Energy Partnership 

Paul Reeves, Partnership for Resource Conservation 

Paul Kriescher, Lightly Treading 

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 
Affordable High-Performance Technical Report

NREL/TP-550-31650 Homes: The 2002 NREL Denver April 2005 

Habitat for Humanity House, A 

Cold-Climate Case Study 

P. Norton and B. Stafford 

National Renewable Energy Laboratory 

B. Carpenter 

Habitat for Humanity 

C.E. Hancock and G. Barker 

Mountain Energy Partnership 

P. Reeves 

Partnership for Resource Conservation 

P. Kriescher 

Lightly Treading 

Prepared under Task No. BET5.8004 

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 

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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 

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Table of Contents 

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

Acknowledgments ...........................................................................................................iv 

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

Anatomy of a Well-Built Home..................................................................................... 2 

Superior Features are Standard at Habitat Metro Denver ........................................... 2

Excellent Cold-Climate Energy Features..................................................................... 3 

Dedicated to Improvement: The Energy Demonstration House Approach .................. 3 

The Habitat/NREL Energy Demonstration House........................................................ 4

High-Performance Comfort.......................................................................................... 5 

Solar Electricity for Habitat Homes Step-By-Step ........................................................... 7 

Where to from Here? ................................................................................................... 9 

Now it's Your Turn ....................................................................................................... 9 

Design and Build an Energy Demonstration Home ..................................................... 9 

Contacts .................................................................................................................... 10 

Habitat for Humanity of Metro Denver ....................................................................... 10 

National Renewable Energy Laboratory .................................................................... 10 

Appendix: Let's Do the Numbers.................................................................................. 11 

Simulated Performance ............................................................................................. 12 

iii 
Acknowledgments 

The authors thank Midwest Research Institute, Battelle, and Bechtel for their sponsorship of the 2002 

NREL/Habitat home. We also thank NREL management, including Director Admiral Richard Truly and 

Associate Director Jessie Harris, for their key support in the project. We appreciate all the staff and 

volunteers of Habitat for Humanity Metro Denver who applied their hard work and dedication to high 

quality, energy-efficient home construction. NREL staff members volunteered their time to design the 

home, organize the project, and help build the home. Special thanks to the Ruibal family for their support 

and patience during testing, sensor installation, and data collection. 

This report is available on the World Wide Web at http://www.BuildingAmerica.gov. 

iv 
Introduction 

A trend towards “green” 

building with a focus on energy 

efficiency is sweeping the 

United States homebuilding 

industry. An integrated systemsdesign approach leads to homes 

that are more efficient, more 

comfortable, more affordable, 

and more durable than homes 

built with standard practices. 

Habitat for Humanity affiliates 

throughout the country are 

taking the lead on this approach 

to home building for affordable 

housing. This approach supports 

Habitat’s goals of supplying 

quality housing and reducing 

the energy cost burden on 

families in Habitat 

homes―goals that are 

especially important in these 

days of increasing energy costs. 

How can your local Habitat 

affiliate begin to incorporate an 

integrated design approach and 

advanced building techniques to 

build more energy -efficient 

homes? A common approach is 

to build an Energy 

Demonstration Home. This 

home is used to try out a wide 

range of energy efficient 

techniques and technologies that 

may be a good fit with your 

building style. The experience 

gained in this process is then 

used to choose which features of 

the demonstration house can be 

used to improve all the homes 

you build. This process can be 

repeated periodically to 

continuously improve your 

homes. 

One Habitat affiliate that has 

used this approach is Habitat for 

Humanity of Metro Denver. 

Through a series of Energy 

Demonstration Homes built in 

partnership with the U.S. 

Department of Energy’s (DOE) 

National Renewable Energy 

Laboratory (NREL) and the 

Building America Program, 

they have fine-tuned their 

standard construction to be 

highly efficient, cost-effective, 

and volunteer friendly. They are 

now nationally recognized as 

energy-efficient building 

leaders. This report describes 

their most recent Energy 

Demonstration Home, built in 

partnership with NREL in 2002. 

Habitat for Humanity of Metro Denver – An Award-Winning Builder 

The outstanding work of Habitat for Humanity of Metro Denver has not gone unnoticed. In October 2003, 

they were awarded an ENERGY STAR® New Millennium Builder Award. This award recognizes builders 

that have designed, constructed, and marketed top-quality, high-performing homes judged to be the best in the 

state. 

“These builders understand that by constructing homes that use less energy, they are having a positive impact 

on Colorado’s environment and Colorado’s future,” said Patty Crow, the ENERGY STAR representative for 

Colorado. “Energy-efficient homes like these are part of the system we are all trying to build to provide 

benefits to individual home owners and to our communities.” 

1 
Anatomy of a Well-Built 

Home 

Every house built by Habitat 

Metro Denver is tight, wellinsulated, and energy efficient. 

Their homes typically receive 

an ENERGY STAR Colorado 

energy rating of 88 or higher, 

when a comparable typical 

home in Colorado would rate 

only a 77. Habitat achieved this 

remarkable quality through a 

dedication to improvements 

over many years. Habitat has 

opened its doors to the DOE 

through NREL and Building 

America’s Building Science 

Consortium (BSC). 

Through these partnerships, 

they have developed an 

integrated approach to home 

design and construction that 

combines carefully planned and 

executed details with high 

efficiency equipment and 

appliances. This means that 

Habitat homeowners spend less 

of their limited resources on 

home energy bills 

Superior Features are 

Standard at Habitat 

Metro Denver 

An efficient home design must 

be responsive to the climatic 

conditions where it is located. 

Habitat Metro Denver designs 

every house they build with this 

in mind. Each house includes a 

host of energy-efficient features, 

including the items listed on the 

next page. 

create the . Habitat staff 

th

NREL and Habitat: Energy Efficiency and Renewable Energy 

Technologies are Key Features of Affordable Housing 

NREL’s mission is to develop renewable energy and energy efficiency technologies and practices, advance 

related science and engineering, and transfer knowledge and innovations to address the nation's energy and 

environmental goals. Habitat for Humanity seeks to eliminate poverty housing and homelessness and to 

make decent shelter a matter of conscience and action. These goals are a perfect match when it comes to 

designing and building homes. Habitat homes are an ideal platform for transferring energy efficiency 

knowledge and technology, thereby reducing the operating cost of the homes for the families that own them. 

For nearly 20 years, NREL and Habitat for Humanity have worked together to create durable, comfortable, 

energy-efficient affordable housing. NREL staff have advised Habitat affiliates nationwide on passive solar 

design and the use of an integrated design approach, and volunteered their time to participate in several 

builds, including a Jimmy Carter blitz build. 

In 1997, NREL’s Exemplary Buildings Program partnered with Habitat for Humanity of Metro Denver to 

Earth Smart House Through the design and building of the Earth Smart House, 

mastered energy-efficient techniques that have become part of every home they build. Habitat of Metro 

Denver continually strives to improve their homes. 

One approach is the building of energy efficient 

demonstration homes where a plethora of energy efficiency 

techniques and technologies can be tried out. Those techniques that 

perform well, are volunteer-friendly, and are cost effective are then 

propagated into every home they build. 

In 2000, Habitat Metro Denver worked with Building Science 

Corporation under the Building America program to build 

several demonstration homes that included many techniques 

now part of Habitat Metro Denver’s standard practice. 

In 2002 the NREL 20 Anniversary House outlined in this 

report was Habitat’s energy demonstration home. In 2005, 

NREL and Habitat are partnering again to build a Zero Energy 

Home – a highly efficient home that produces as much energy 

as it consumes. 

The Valdez Family in front of their Earth 

Smart Home built by Habitat for Humanity 

of Denver. 

2 
 An R value is a measure of 

resistance to

2

 OSB is 

3

 Low-e windows 

Excellent Cold-Climate 

Energy Features 

A well-insulated building 

shell 

• Walls with 2x6 studs 24-in. 

on center with R-191

 cavity 

insulation and 1⁄2-in. XPS 

foam over one layer of 1⁄2-in. 

OSB2

 sheathing 

• Raised heel trusses and R-38 

attic insulation 

• Low-e3

 vinyl windows 

• Header design that allows 2­

in. foam insulation in the 

header space 

• 2-in. extruded polystyrene 

foam (XPS or “blue board”) 

on the interior face of 

crawlspace walls. 

A well-sealed building shell 

• Edges of OSB exterior 

sheathing caulked before 

being nailed onto walls 

• Exterior sheathing seams 

taped with building tape 

• All building envelope 

penetrations sealed with sill 

seal, caulk, or spray foam. 

Good solar control 

• Site and building design to 

allow maximum solar gain 

in the winter wherever 

possible 

• 24-in. eave overhangs for 

Energy-efficient 

equipment, appliances, 

and lighting 

• Front-loading washing 

machine 

• Direct-power vent, highefficiency gas water heater 

• Programmable thermostat 

• 90%-efficient closedcombustion furnace 

• Compact fluorescent lights 

• All HVAC duct work sealed 

and tested 

• Continuous ridge and soffit 

vents. 

Developing a similar package of 

features for the homes you build 

is an evolutionary process 

requiring partnership with 

building energy experts and 

equipment suppliers. A 

balanced approach that 

addresses techniques to make a 

better building shell with the 

inclusion of properly sized, 

efficient equipment and 

appliances will deliver comfort, 

durability, and low energy costs 

to your homeowners. 

Dedicated to 

Improvement: The 

Energy Demonstration 

House Approach 

How does one learn to build 

energy efficient homes? By 

doing it! Habitat Metro Denver 

works to continuously improve 

the efficiency of their homes by 

exploring new techniques and 

technologies in Energy 

Demonstration Homes. 

shading in the summer Habitat Metro Denver used Building America's integrated design 

approach to build this award-winning home in Denver, Colorado. 

1

1

 An R value is a measure of resistance to heat loss. The higher the R-Value, the less heat is lost. Its units are 

hr·ft2

·°F/Btu. 2

 Oriented-strand board 

3

 Low-e windows have a low emissivity coating that reduces the heat loss through the window. 

3 
The Habitat / NREL 

Energy Demonstration 

House 

In 2002, Habitat for Humanity 

of Metro Denver built a home 

like no other they had ever built. 

Designed and constructed in 

partnership with the DOE’s 

National Renewable Energy 

Laboratory as part of NREL’s 

25th anniversary celebration, the 

house featured a well-sealed and 

insulated shell, highperformance windows, zoned 

radiant wall heating, high 

efficiency appliances, solar 

water heating, and a 

photovoltaic (PV) solar electric 

system. The home was 

evaluated by an independent 

energy rater and given an EStarTM Colorado score of 95, 

making it one of the most 

efficient homes ever rated by EStar. During the America Solar 

Energy Society’s National Solar 

Home Tour in October 2002, 

visitors were given the 

opportunity to tour the Habitat 

/NREL home and gain firsthand experience of a well 

integrated solar home. 

Spray foam insulation 

Beginning with Habitat’s 

impressive list of standard 

efficiency features, a group of 

NREL’s building energy 

engineers donated their time to 

review the design and suggest a 

series of energy upgrades. In 

consultation with the Habitat 

construction team and energy Solar water-heating committee, this list was 

evaluated along with other collectors 

suggestions. To reach 

consensus on the final design, 

the evaluators looked at the • A 1.8-kW net-metered PV 

“volunteer friendliness” of each system and a solar water idea and the availability of heating system were added materials and expertise. to the home. 

• A high efficiency boiler and 

zoned radiant wall system 

was used in place of a 

furnace and ductwork. 

• The design was made ADA4 

compliant by hanging the 

floors in the foundation to 

reduce step-up into house 

and designing the bathroom 

for wheelchair use. 

Placement of the PV • Light-colored roofing 

shingles and increased attic 

ventilation were used to 

Here is a list of the final design reduce attic overheating. 

changes: • Compact fluorescent 

• Spray foam insulation was lighting was used 

used in place of fiberglass throughout the home and a 

batts to improve insulation tubular skylight was used 

consistency and air for garage lighting. 

tightness. The spray foam

was used in the walls, 

ceiling, and floor of the 

home. 

• East- and west-facing 

window areas were reduced 

and south-facing windows 

were increased to provide 

solar tempering. 4

 ADA = Americans with 

Disabilities Act 

4 
 Percent of Water Heating Energy Supplied by Solar

High-Performance 

Comfort 

In February 2003, NREL staff 

of the DOE’s Building America 

Program installed sensors in the 

home to track its energy 

performance. They also 

completed a computer 

simulation of the home to study 

the energy performance. 

During the summer of 2003, the 

solar water-heating system 

provided between 50% and 78% 

of all the energy used for water 

heating in the home, lowering 

the homeowner’s energy bills 

(Figure 1). 

The solar electric system is 

producing an average of about 

one-third of the electricity used 

in the home (Figure 2). This 

simple system has no batteries 

to take care of; instead, the 

system feeds electricity into the 

90% 

80% 

70% 

60% 

50% 

40% 

30% 

20% 

10% 

0% 

utility grid when the home is 

producing more electricity than 

it needs and pulls electricity 

from the utility grid when it 

needs more electricity than it is 

producing. At times, the electric 

meter on the home actually runs 

backward. This arrangement, 

called “net metering,” is now 

available in most states. 

The cost of solar electric 

systems continues to decrease, 

but they are currently unable to 

economically compete with 

electricity purchased from the 

grid. Still, there are myriad 

reasons you may want to 

consider a solar electric system 

on your Energy Demonstration 

Home including the 

environmental benefits, the 

demonstration of your 

commitment to clean energy, 

and energy bill reductions for 

your homeowners. In addition, 

it may lead to press visibility for 

your local Habitat efforts that 

can increase sponsorship. 

When the energy efficiency 

features of the home are 

combined with solar water 

heating and solar electricity, the 

home saves about 60% of the 

total energy that would be used 

in an identical home built using 

standard practices. Figure 3 

shows how key features of the 

home contribute to the overall 

energy savings. The leftmost bar 

shows the annual energy 

consumption of the standard 

practice home. Each color in the 

bar shows where the energy is 

being used. The second bar 

shows that the standard Habitat 

Metro Denver home uses 

significantly less energy than 

the standard home. The 

remaining bars illustrate how 

much savings each of the key 

energy efficiency measures 

produces, with the rightmost bar 

illustrating the total energy 

consumption of the 

Habitat/NREL home. 

Summer average = 64% 

May June July August September 

Figure 1. Percentage of Water Heating Energy 

Supplied by Solar Hot Water System 

5 
Percent of Electricity Supplied by PV System 

0% 

5% 

10% 

15% 

20% 

25% 

30% 

35% 

40% 

45% 

April May June July August September October November 

Average = 33% 

6 

Figure 2. Percentage of Electricity Supplied by PV 

System 

Denver Habitat House 

Source Energy Consumption by Conservartion Measure & End-Use 

0 

20 

40 

60 

80 

100 

120 

140 

160 

180 

BA Benchmark Home 

Standard Denver Habitat Home 

Foam insulation in walls 

Foam insulation in ceilings 

Foam insulation in crawlspace 

Efficient water heater 

High efficiency boiler 

Solar water heater 

Efficient lighting and appliances 

Habitat/NREL home with PV 

Source MBTU/yr 

Tot al 

Out door Light i ng 

Wat er Heat ing 

S pac e Cooling 

S pac e Heat ing 

A pplianc e & P lug 

Indoor Li ght i ng 

Figure 3. Source energy consumption by conservation measure and 

end use 
Solar Electricity for Habitat Homes Step-By-Step 

A grid-connected PV system is the lowest cost of the different types of PV systems. However, it can 

still be relatively expensive relative to the total house cost and other household systems. The total 

installed cost of a system can range from $10,000 to $20,000 for a 1- to 2-kW system. The total 

system cost may be less if there are federal, state, or local rebates. 

Step #1. Will the house be located in an area where a utility grid-connection is permitted or 

available? Is there a local or national supplier willing to donate system components? Check 

with your local utility company, or check with a local PV system installer who has installed 

grid-connected systems. PV system costs can be high, so component donations may be a 

key factor that determines if PV can meet affordability requirements. 

Step #1b. Will the homeowner accept responsibility for the system after it is installed? There is some 

maintenance required, such as periodically checking the installation to see that it is 

undamaged and operating properly. When the roof needs replacing the homeowner will 

incur an additional cost because the PV system must be removed and then reinstalled. The 

type of mounting system will affect this cost. 

Step #2. Most utilities are required to buy back the excess PV electricity. The questions are at what 

price and are there additional charges, liability insurance requirements, or equipment 

requirements? It may be legally required, yet difficult to implement. In the best cases, the 

utility pays a higher price for the renewable PV electricity than the homeowner pays for 

energy from the grid. More commonly, the utility offers “net metering” where the utility 

pays the same for the PV electricity as it charges for its own electricity. Usually, net 

metering uses a single meter system that “spins” forward when the home is consuming more 

electricity than it is producing and backward when producing more than it is consuming. 

Most homes are on a standard fixed rate – the energy price is the same for every hour of the 

day. Ask the local utility whether the home could be converted to a time-of-use schedule 

with net billing. Because the PV system produces power that often closely matched peak 

demand, it is beneficial to be on a time-of-use schedule where electricity is priced higher 

during peak demand hours. 

Step #3. Make sure the house can accommodate a PV system on the roof. Generally, the roof can 

support the additional weight of the PV modules, but check with the local building codes 

and the architect. A sufficiently large, generally south-facing roof is required. The PV 

system should be installed parallel to the roof, but with a 4-6” separation from the roof. 

Several PV mounting systems exist. Many are “retrofit” systems that are installed after the 

roof is completed. A “retrofit” system will include roof penetrations through the roofing 

system into the rafters. Care needs to be taken to prevent leaks—follow the manufacturers 

installation instructions. Other PV mounting systems include mounting posts that are 

mounted first and then flashed around when the roof is installed. These systems require a 

slightly greater roofing skill level because there are many more flashings, but are easier 

when a roof replacement is required. 

7 
Solar Electricity for Habitat Homes Step-By-Step (continued) 

Step #3b. Make sure there is space for the inverter and disconnects. Most inverters and 

disconnects can be installed in a 4-ft x 4-ft wall area. Reserve or plan for this space 

inside the garage or outside by the service entrance. Make sure the area is at a good 

working height and yet reasonably protected from accidental physical damage. For 

example, don’t place the inverter in the garage where a car or house door could hit it or 

in the normal people-traffic path. All system displays and indicators should be at eyelevel for the homeowner. 

The best location for outdoor-rated inverters is outside on the north wall. The worst 

location is outside on the south wall. While the inverter is outdoor-rated, high 

temperatures caused by direct sunlight on the inverter will have a negative effect on the 

performance of the inverter and the lifetime of the inverter. Check the installation 

requirements for the specific inverters. A location inside a garage may be acceptable, 

but, again, check the installation instructions because there may be insufficient air flow 

for some inverters. Read the instructions or have the installer point out the relevant 

manufacturer installation instructions. In a tactful manner, don’t accept an installer’s 

general assertion that he always does it this way, and he’s never had any problems. 

Follow the installation instructions in case there are future warranty claims and to 

maximize the lifetime beyond the warranty period. 

Step #4. Who will install the PV system? People familiar with the PV mounting system, and 

preferably a licensed electrician or a certified solar installer, should install most PV 

systems. Check with the local and state codes for installation regulations. 

Step #5. Who will pay for the PV system? It’s great if you can get someone to donate a system 

and the installation. Ask around. Someone may donate the system cost, and someone 

else may sell the system to you at cost. One can ask local installers or contact the 

manufacturers directly. However, the difficulty of asking manufacturers is that there are 

several manufacturers for a complete PV system. There are different manufacturers for 

the PV modules, the mounting structure, the inverter and the miscellaneous switches and 

boxes. We found a module manufacturer that would also pick up the tab on the other 

equipment―this may not be available in all cases. 

Step #6. Fill out the paperwork. There may be application forms for rebates—check the exact 

requirements before the system is bought or installed. Coordinate with the local utility 

on their requirements for the system checkout. 

Step #7. Have a system orientation and checkout with the homeowner. Make sure there is a onepage laminated quick instructions and guidelines next to the inverter or closeby that tells 

how to turn the system on or off and how to tell if it’s working okay. Leave a name and 

phone number for future questions. 

Step #8. Follow up with the homeowner in a month or so, to see how the system is working, 

check for roof leaks, and ask if there are any questions. 

8 
Where to from Here? 

The NREL Denver Habitat 

Zero Energy Home 

NREL and Habitat Metro 

Denver are teaming again to 

push the boundaries of energy 

efficiency even further. In 2005 

we will build a Zero Energy 

Habitat Home. This home is 

being designed to produce as 

much energy as it consumes on 

an annual basis. The design will 

be based on the lessons learned 

from the 2002 Energy 

Demonstration Home. 

Now It’s Your Turn! 

To start building more 

comfortable, durable, and 

energy efficient homes, try these 

steps: 

Make a commitment 

Educate yourself 

The Internet is a great place to 

start to come up to speed on 

energy efficient building 

practices. 

Seek Partners 

Connect with local home energy 

raters (find them at 

http://www.natresnet.org/dir/rat 

ers/default.htm) and ask them 

about local building energy 

specialists that may be able to 

help you. 

Design and Build an 

Energy Demonstration 

Home 

Use the expertise of your new 

partners to create a home design 

that incorporates energyefficient techniques and 

technologies that fit with your 

local building style and needs. 

Use the experience of the 

Energy Demonstration 

Home 

Identify the most effective 

combination of features of your 

demonstration house and make 

them standard in every home 

you build. 

Share your experiences 

with other Habitat 

affiliates! 

So You Want to Build a Better Home? 

http://www.habitat.org/env/ 

= 

Housing Network: / 

Here are some World Wide Web pages that will get you started . . . 

The Building America Program: www.buildingamerica.gov 

The Top 25 Web Sites for Home Builders and Home Buyers of Energy-Efficient Homes 

www.eere.energy.gov/buildings/building_america/for_builders_top25.html 

EPA’s ENERGY STARTM Homes and appliances: www.energystar.gov 

Habitat for Humanity International Construction and Environmental Resources: 

Home Energy Magazine: www.homeenergy.org 

The Energy and Environmental Building Association: www.eeba.org 

ToolBase Green Building site: http://www.toolbase.org/secondaryT.asp?CategoryID=1&TrackID

If you’re in a cold climate, check out Building Science Corporation’s Habitat house design for cold 

climates: http://www.buildingscience.com/about/habitat/default.htm 

Superinsulated cold-climate Habitat House designs are also available from the National Affordable 

http://www.nahn.com

Examples of energy characteristics for ENERGY STAR Habitat Homes in various climates are available 

from the Florida Solar Energy Center at 

http://www.fsec.ucf.edu/bldg/baihp/CASESTUD/Hfh_EStar/index.htm 

9 
Contacts 

Habitat for Humanity of Metro Denver 

Lori Vaclavik 

Executive Director 

1500 W. 12th Ave. 

Denver, CO 80204-3410 

(303) 534-2929 

National Renewable Energy Laboratory 

Paul Norton 

Senior Engineer, Building America Program

1617 Cole Blvd. MS 1725

Golden, CO 80401-3393 

(303) 384-7545 

10 
Appendix: Let’s Do the Numbers 

Simulated Performance The tables below summarize the results of comparing analysis results and performance measurements of the NRE

conventional homes. Details on the analysis procedures used to generate these results can be found on the Buildi

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

Home 

/

Home 

/ / /

62 49 38 39% 15

5 2 2 68% 1% 2% 

DHW 29 29 7 77% 14

18 11 7 60% 

45 45 39 11% 

0 0 0 

159 135 93 41% 41

0 0 18

159 135 64 59% 59

Building 

America 

Benchmark 

Habitat Metro

 Denver 

Standard 

Habitat NREL 

Energy 

Demonstration 

Compared to 

Building 

America 

Benchmark 

Compared to 

Habitat 

Standard 

Home 

Compa

Build

Ame

Bench

End-Use MBTU yr MBTU yr MBTU yr Space Heating 23% Space Cooling 

77% 

Lighting 33% 7% 

Appliances + Plug 11% 3% 

OA Ventilation 0% 0% 0% 

Total Usage 31% 

PV System Generation -29 

Net Energy Use 

Percent of End-Use 

Source Energy Savings of Energy D

Annual Source Energy 

Notes: 

The "Percent of End-Use" columns show how effective the prototype building is at reducing energy use in each end-u

 The "Percent of Total" columns show how the energy reductions in each end-use category contribute to the overall sa

11 
National Average Builder Standa

Site Energy Source Energy Energy Cost Energy Cost 

Increment kWh therms MBTU Savings % $/yr Savings % $/yr Savings % 

Building America Benchmark Home 5905 834 158.6 $ 481 $ 1,021 

Habitat Metro Denver Standard Practice Home 5014 713 135.3 15% $ 408 15% $ 870 Habitat Standard Home + Foam Insulation in walls 5011 710 134.9 15% $ 408 15% $ 868 0% Above features + Foam insulation in ceiling 4964 703 133.6 16% $ 404 16% $ 860 1% Above features + Crawlspace Foam Insulation 5167 654 129.9 18% $ 421 12% $ 844 3% Above features + High effiency water heating 5167 594 122.8 23% $ 421 12% $ 806 7% Above features + High effiency boiler 4619 578 115.3 27% $ 376 22% $ 751 14% Above features + Solar water heating 4619 447 99.9 37% $ 376 22% $ 666 24% Above features + Efficient Lighting and appliances 3771 461 92.9 41% $ 307 36% $ 606 30% 

Site Generation 

Above features + 

Photovoltiac system 981 461 64.3 59% $ 80 $ 379 56% 

Notes: "Source Energy Savings %" and "National Average Energy Cost Savings %" compared to the Building America base case the "Energy Cost Savings %" and the "Package savings $/yr" are compared to the Builder Standard Practice case. Colorado Average Electric Cost : 0.08 $/kWh (Nov. 2003) Colorado Average Gas Cost: 0.65 $/therm (Dec. 2003) (Source: US Energy Information Agency) 

12 
REPORT DOCUMENTATION PAGE Form Approved 

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1. REPORT DATE (DD-MM-YYYY) 

April 2005 

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Technical Report 

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4. TITLE AND SUBTITLE 

Affordable High-Performance Homes: The 2002 NREL Denver 

Habitat for Humanity House, A Cold-Climate Case Study 

5a. CONTRACT NUMBER 

DE-AC36-99-GO10337 

5b. GRANT NUMBER 

5c. PROGRAM ELEMENT NUMBER 

6. AUTHOR(S) 

Paul Norton, Byron Stafford, Bruce Carpenter, Edward Hancock, 

Greg Barker, Paul Reeves, Paul Kriescher 

5d. PROJECT NUMBER 

NREL/TP-550-36150 

5e. TASK NUMBER 

BET5.8004 

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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/TP-550-36150 

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NREL 

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National Technical Information Service 

U.S. Department of Commerce 

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13. SUPPLEMENTARY NOTES 

14. ABSTRACT (Maximum 200 Words) 

A trend towards “green” building with a focus on energy efficiency is sweeping the United States homebuilding 

industry. An integrated systems-design approach leads to homes that are more efficient, more comfortable, more 

affordable, and more durable than homes built with standard practices. Habitat for Humanity affiliates throughout the 

country are taking the lead on this approach to home building for affordable housing. This approach supports 

Habitat’s goals of supplying quality housing and reducing the energy cost burden on families in Habitat 

homes―goals that are especially important in these days of increasing energy costs. 

15. SUBJECT TERMS 

Habitat for Humanity; Affordable Houses; energy efficiency; National Renewable Energy Laboratory; green building; 

integrated systems-design 

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focuses on two key areas: 

Research and development of the 

equipment 

to optimize building performance 

1-877-EERE-INF (1-877-337-3463) 

An electronic copy of this factsheet is 

Building America Program 

ildi i ildi l i I

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i i i I i l

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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. 

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 mprove the energy effic ency 

of our nation’s buildings through innovative new technologies and better 

building practices. The program 

• Emerging Technologies 

next generation of energy-efficient 

components, materials, and 

• Technology Integration 

Integration of new technologies 

with innovative building methods 

and savings 

For more information contact: 

EERE Information Center 

www.eere.energy.gov 

available on the Building America Web 

site at www.buildingamerica.gov 

U.S. Department of Energy 

Energy Efficiency 

and Renewable Energy 

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 

Bu ng Amer ca Program • Office of Bu ng Techno og es, EE-2J • U.S. Department of Energy • 1000 ndependence 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 

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 W nter • Steven W nter Assoc ates, nc. • 50 Wash ngton Street • Norwa k, 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 

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 

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. 

April 2005 • NREL/TP-550-36150 

Printed with a renewable-source ink on paper containing at least 50% wastepaper, including 20% postconsumer waste. 

Visit our Web sites at: 

www.buildingamerica.gov www.energystar.gov