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T OF ENERGY

DEPARTMEN

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NITED STAT S OFA ERICA

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Research Toward Zero Energy Homes January 2007 • NREL/TP-550-40968

Building America Research Benchmark 

Definition, Updated December 15, 2006

Robert Hendron

National Renewable Energy Laboratory

All Events over 3 Week Period

0

100

200

300

400

500

600

700

800

0 3 6 9 12 15 18 21

Day Number

Liter/hour

Clothes Washer

Dishwasher

Bath

Shower

Sink

0

5 0

1 0 0

1 5 0

2 0 0

2 5 0

3 0 0

3 5 0

4 0 0

4 5 0

1 2 3 4 5 6 7 8 9 1 0 1 1 1 2 1 3 1 4 1 5 1 6 1 7 1 8 1 9 2 0 2 1 2 2 2 3 2 4

Average Hourly Electricity (kWh/hr)

MELs Refrigerator Range Dishwasher Clothes Dryer Clothes Washer

Hour of Day
Building America Research 

Benchmark Definition, Updated 

December 15, 2006 

Robert Hendron 

Prepared under Task No. BET7.8004 

Technical Report 

NREL/TP-550-40968 

January 2007 

National Renewable Energy Laboratory

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303-275-3000 • www.nrel.gov 

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Office of Energy Efficiency and Renewable Energy 

by Midwest Research Institute • Battelle 

Contract No. DE-AC36-99-GO10337
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Table of Contents 

Definitions................................................................................................................ iv 

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

Benchmark House Specifications..............................................................................1 

Building Envelope ...................................................................................................................... 2 

Space Conditioning/Air Distribution Equipment........................................................................ 8 

Domestic Hot Water ................................................................................................................... 9 

Air Infiltration and Ventilation ................................................................................................. 16 

Lighting Equipment and Usage ................................................................................................ 16 

Appliances and Miscellaneous Electric Loads ......................................................................... 19 

Site Generation.......................................................................................................................... 26 

Modeling the Prototype............................................................................................................. 26 

Operating Conditions.............................................................................................. 27 

Reporting Energy Use and Energy Savings............................................................ 31 

References............................................................................................................... 34 

iii
Definitions 

A/C air conditioning 

ACCA Air Conditioning Contractors of America 

ACH air changes per hour 

AFUE Annual Fuel Utilization Efficiency 

ASHRAE American Society of Heating, Refrigerating & Air 

Conditioning Engineers 

ASTM American Society for Testing and Materials 

BA Building America 

CEC California Energy Commission 

CFA Conditioned Floor Area 

cfm cubic feet per minute 

DHW domestic hot water 

DOE U. S. Department of Energy 

DSE distribution system efficiency 

DUF dryer usage factor 

EER energy efficiency ratio 

ELA Effective Leakage Area 

ELCAP End-Use Load and Consumer Assessment Program 

EPA U.S. Environmental Protection Agency 

FFA finished floor area 

FHA Federal Housing Administration 

FSEC Florida Solar Energy Center 

HERS Home Energy Rating System 

HP heat pump 

HUD U.S. Department of Housing and Urban Development 

ICC International Code Council 

IECC International Energy Conservation Code 

LBNL Lawrence Berkeley National Laboratory 

MAT monthly average temperatures 

MEC Model Energy Code 

MEL miscellaneous electric loads 

NAECA National Appliance Energy Conservation Act 

NASEO National Association of State Energy Officials 

iv
NREL National Renewable Energy Laboratory 

RECS Residential Energy Consumption Study 

RESNET Residential Energy Services Network 

SCE Southern California Edison Company 

SDT summer design temperatures 

SEER seasonal energy efficiency ratio 

SLA Specific Leakage Area 

TMY2 Typical Meteorological Year, Version 2 

TPU Tacoma Public Utilities 

TRNSYS TRaNsient SYstem Simulation Program 

UA heat loss coefficient 

WDT winter design temperature 

v
Building America Research Benchmark Definition 

National Renewable Energy Laboratory 

Updated December 15, 2006 

Introduction 

To track progress toward aggressive multi-year, whole-house energy savings goals of 40%–70% and 

onsite power production of up to 30%, the U.S. Department of Energy (DOE) Residential Buildings 

Program and the National Renewable Energy Laboratory (NREL) developed the Building America 

Research Benchmark in consultation with the Building America industry teams. 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 hot water. Unlike the reference homes used for HERS, Energy Star, and most 

energy codes, the Benchmark represents typical construction at a fixed point in time so it can be used as 

the basis for Building America’s multi-year energy savings goals without the complication of chasing a 

“moving target”. As time passes, we expect energy codes to become more and more energy efficient 

compared to the Benchmark as better construction practices and more efficient equipment become 

commonplace in the market. 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. The Benchmark is only 

intended for use with detached and attached single-family housing. It is not suitable for multi-family 

housing as written. 

Benchmark House Specifications 

The following sections summarize the definition of the Benchmark, updated for the FY07 Building 

America subcontracts. A comprehensive description of other important Building America reference 

houses (Builder Standard Practice and Regional Standard Practice), along with guidance for using hourly 

simulation tools to compare an energy-efficient prototype house to the various base-case houses, can be 

found in the NREL technical report addressing systems-based performance analysis of residential 

buildings (Hendron et al 2004). NREL and other Building America partners have also developed a series 

of tools, including spreadsheets with detailed hourly energy usage and load profiles, to help analysts 

apply the Benchmark quickly and in a consistent manner. These tools can be found on the Building 

America Web site (http://www.eere.energy.gov/buildings/building_america/pa_resources.html). 

Any element of the Benchmark definition that is not specifically addressed in the following sections is 

assumed to be the same as the Prototype house. Because the definition is intended to be software-neutral, 

certain elements of the Benchmark cannot be modeled directly using every common simulation tool. If 

the energy use associated with such elements is significant, then they should be modeled or handcalculated separately from the building model and reasonable adjustments should be made to the wholehouse simulation results. If there is no significant energy effect associated with these elements, the 

Prototype and Benchmark should be modeled using similar approximations in an energy-neutral manner. 

The full Building America Performance Analysis Procedures (Hendron et al 2004) include application 

notes addressing some practical implementation issues that may be encountered when simulating the 

Benchmark using DOE-2.2 or EnergyGauge. 

1
Building Envelope 

All building envelope components (including walls, windows, foundation, roof, and floors) for the 

Benchmark shall be consistent with the HERS Reference Home as defined by the National Association of 

State Energy Officials (NASEO) and the Residential Energy Services Network (RESNET) in the 

“National Home Energy Rating Technical Guidelines,” dated September 19, 1999 (RESNET 2002). 

These requirements are summarized below, along with a few minor clarifications and additional 

requirements. References to U-values in the 1993 Model Energy Code have been updated to 2003 

International Energy Conservation Code (IECC), because the corresponding U-values are identical and 

the IECC is more readily available (ICC 2003). 

The Benchmark envelope specifications are as follows: 

• The same shape and size as the Prototype 

• The same area of surfaces bounding conditioned space as the Prototype with the exception of the 

attic, which shall be insulated at the attic floor and have a ventilation area of 1 ft2

 per 300 ft2

ceiling area, regardless of the Prototype attic design 

• The same foundation type (slab, crawl space, or basement) as the Prototype 

• The same basement wall construction type as the Prototype (e.g., masonry, wood frame, other) 

• No sunrooms 

• No horizontal fenestration, defined as skylights, or light pipes oriented less than 45 degrees from 

a horizontal plane 

• Window area (AF), including framing, determined by Equation 1 for detached homes and by 

Equation 2 for attached homes 

Equation 1: AF = 0.18 x AFL x FA , 

Equation 2: AF = 0.18 x AFL x FA x F , 

 where 

AF = total window area (ft2

) 

 AFL = total floor area, including basement (ft2) 

FA = (exposed thermal boundary wall area)/(total thermal boundary wall area). 

F = (total thermal boundary wall area)/(total thermal boundary wall area + 

common wall area), or 0.56, whichever is greater, 

 and where 

total thermal boundary wall is any wall that separates directly or indirectly 

conditioned space from unconditioned space or ambient conditions, 

including all insulated basement walls but not including unvented 

crawl space walls; 

exposed thermal boundary wall is any thermal boundary wall not in contact 

with soil; and 

common wall area is the total area of walls adjacent to another conditioned 

living unit, including basement and directly or indirectly conditioned 

crawl space walls. 

• The window area calculated above is distributed with the same proportion on each wall and on 

each floor as the Prototype house. Thirty-three percent of the window area on each facade is can 

be opened for the purpose of natural ventilation. The energy use is calculated with the 

Benchmark house in each of four orientations rotated in 90° increments relative to the Prototype 

orientation (+0°, +90°, +180°, +270°), and the average of these four cases is used to represent the 

energy use of the Benchmark. 

2
• Thermal conductance of all thermal boundary elements equal to the requirements, expressed as U 

values, of Paragraph 502.2 of the 2003 IECC (ICC 2003), as summarized below. Unless 

otherwise specified, these U-values are for entire assemblies, including sheathing, framing, 

finishes, and so on. 

o U-value (Uw) for the opaque fraction of exterior walls from Table 1 or 2, as appropriate. 

o The U-value and solar heat gain coefficient (SHGC) for vertical fenestration, including 

windows and sliding glass doors, shall be determined using Table 3. The values in Table 

3 were calculated based on the HERS methodology for determining maximum window 

U-value, assuming a floor area to wall area ratio of 1.0. If the simulation tool uses a 

window library, a window that approximately matches the UF and SHGC shall be 

selected, and the frame R-value shall be increased or decreased until the overall window 

UF matches the value in Table 3. 

Table 1. Opaque Wall U-Values (Uw) for Detached Homes (excerpted from ICC 2003) 

Annual Heating Degree Days Base Uw Air to Air, 

65 (HDD65) from Nearest Location 

Listed in Chapter 9 of ASHRAE 

Standard 90.2 or NREL’s Solar 

Radiation Data Manual

Includes 

Framing 

(Btu/hr-ft2

-°F) 

> 13,000 0.038 

9,000–12,999 0.046 

6,500–8,999 0.052 

4,500–6,499 0.058 

3,500–4,499 0.064 

2,600–3,499 0.076 

<2,600 0.085 

Table 2. Opaque Wall U-values (Uw) for Attached Homes (excerpted from ICC 2003) 

Heating Degree Days Base 65 

(HDD65) from Nearest Location 

Listed in Chapter 9 of ASHRAE 

Standard 90.2, or NREL’s Solar 

Radiation Data Manual

Uw Air to Air, 

Includes 

Framing 

(Btu/hr-ft2

-°F) 

>9,000 0.064 

7,100–8,999 0.076 

3,000–7,099 0.085 

2,800–2,999 0.100 

2,600–2,799 0.120 

<2,600 0.140 

 

1

 See Solar Radiation Data Manual for Buildings (or the “Blue Book”) published by the NREL (NREL 1995) 

(http://rredc.nrel.gov/solar/old_data/nsrdb/bluebook/). 

3

1
Table 3. Vertical Fenestration U-values (UF) and SHGC 

HDD65 from Nearest Location 

Listed in Chapter 9 of ASHRAE 

Standard 90.2, or NREL’s Solar 

Radiation Data Manual

UF Air to Air, 

Includes Framing 

and Sash 

(Btu/hr-ft2

-°F)

SHGC, 

Includes 

Framing and 

Sash

≥7,000 0.36 0.32 

6,000–6,999 0.39 0.32 

5,000–5,999 0.46 0.58 

4,000–4,999 0.53 0.58 

3,000–3,999 0.58 0.58 

2,000–2,999 0.62 0.65 

1,000–1,999 0.79 0.65 

≤999 1.00 0.79 

o U-value of an insulated floor above a vented crawl space or other unconditioned space 

shall be as specified in Figure 1 (excerpted from ICC 2003). 

o U-value of insulated walls in an unvented crawl space shall be as specified in Figure 2 

(excerpted from ICC 2003). This U-value represents the combined effect of wall 

components and the surface air film, but it does not include adjacent soil. 

o U-value of insulated basement walls shall be as specified in Figure 3 (excerpted from 

ICC 2003), and the insulation shall be located on the interior surface of the walls. This 

U-value represents the basement wall assembly, including the surface air film, but it does 

not include ground effects. 

o R-value and depth of slab edge insulation for slab-on-grade construction shall be as 

specified in Figure 4 (excerpted from ICC 2003). This R-value is for rigid foam 

insulation and does not include the slab itself or ground effects. 

o U-value of insulated roof/ceiling shall be as specified in Figure 5 (excerpted from ICC 

2003). If the Prototype includes an attic, the Benchmark shall have an unconditioned 

attic with insulation at the attic floor. 

4
0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Annual Heating Degree Days, Base 65

U0 (Btu/h-sqft-oF)

Heating Degree Days 

(HDD) Maximum U0-Factor

0 - 1,000 0.08

1,001 - 2,500 0.07

2,501 - 15,500 0.05

15,501 - 16,500 0.05 - [(HDD - 15,500) x 0.00001]

> 16,500 0.04

Figure 1. U-value of floor over unconditioned space (Excerpted from ICC 2003) 

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Annual Heating Degree Days, Base 65

U0 (Btu/h-sqft-oF)

Heating Degree Days 

(HDD) Maximum U0-Factor

0 - 499 None Required

500 - 2,000 0.15

2,001 - 5,000 0.21 - (HDD x 0.00003)

> 5,000 0.06

Figure 2. Unvented crawl space wall U-value (Excerpted from ICC 2003) 

5
0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Annual Heating Degree Days, Base 65

U0 (Btu/h-sqft-oF)

Heating Degree Days 

(HDD) Maximum U0-Factor

0 - 1,499 None Required

1,500 - 4,500 0.205 - (HDD x 0.0000233)

4,501 - 8,500 0.11125 - (HDD x 0.0000025)

8,501 - 9,000 0.6 - (HDD x 0.00006)

> 9,000 0.06

Figure 3. Basement wall U-value (Excerpted from ICC 2003) 

0

2

4

6

8

10

12

14

16

18

20

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Annual Heating Degree Days, Base 65 (In Thousands)

R-Value (h-sqft-oF/Btu)

Unheated Slab

Heated Slab

2 ft 4 ft

Heating Degree Days 

(HDD) Minimum R-Value

0 - 499 None Required

500 - 4,500 R-6

4,501 - 19,000 2.5862 + (HDD x 0.000759)

> 19,000 R-17

0 - 2,499 None Required

2,500 - 4,500 R-4

4,501 - 19,500 1.0 + (HDD x 0.000666)

> 19,500 R-14

Heated Slab

Unheated 

Slab

Figure 4. Slab insulation R-value and depth (Excerpted from ICC 2003) 

6
0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

Annual Heating Degree Days, Base 65

U0 (Btu/h-sqft-oF)

Heating Degree Days 

(HDD) Maximum U0-Factor

0 - 2,500 0.05 - (HDD x 0.0000056)

2,501 - 3,900 0.036

3,901 - 6,000 0.036 - [(HDD - 3,900) x 0.00000476]

6,001 - 16,000 0.026

16,001 - 16,500 0.026 - [(HDD - 16,000) x 0.000002]

> 16,500 0.025

Figure 5. Roof/ceiling assembly U-value (Excerpted from ICC 2003) 

• No external shading at any time from roof projections, awnings, adjacent buildings, trees, etc. 

Basic architectural features such as attached garages and enclosed porches shall be included in the 

Benchmark model, but the model shall not include window shading effects from these features. 

• No self-shading shall be modeled for the Benchmark. 

• Total area of opaque exterior doors is equal to 40 ft2, facing north, with door U-value equal to 

0.20 Btu/hr·ft2

·°F (air-to-air). 

• Solar absorptivity is equal to 0.50 for opaque areas of exterior walls, and 0.75 for opaque areas of 

roofs. 

• Total emittance of exterior walls and roofs is equal to 0.90. 

• The above-grade exterior walls shall be light-frame 2x4 or 2x6 wood construction with sufficient 

insulation to achieve the correct overall U-value. The framing factors in Table 4 are 

representative of typical construction practices, and shall be used as inputs for the Benchmark 

model. 

Table 4. Benchmark Framing Factors 

Frame Framing 

Spacing 

• Interior partition walls shall be light-frame (2x4) wood construction. 

• Masonry basement floor slabs and slab-on-grade foundations shall have 80% of floor area 

covered by R-2 carpet and pad and 20% of floor area directly exposed to room air. 

Fraction Enclosure 

Element (inches o.c.) (% area) 

Walls 16 23% 

Floors 16 13% 

Ceilings Below 

Unconditioned Space 24 11% 

7
Space Conditioning/Air Distribution Equipment 

Space conditioning equipment type and efficiency for the Building America Benchmark shall meet the 

following requirements: 

• The equipment type and efficiency for the Benchmark shall be based on the type of heating and 

air-conditioning equipment found in the Prototype, as shown in Table 5. 

• If the simulation tool requires the use of Energy Efficiency Ratio (EER) instead of Seasonal 

Energy Efficiency Ratio (SEER) for a heat pump or air conditioner, then the EER for the 

Benchmark shall be calculated using Equation 3. If the actual EER for the Prototype is not 

readily available, Equation 3 may also be used to make an approximate conversion from SEER to 

EER (Wassmer 2003): 

 Equation 3: EER = -0.02 x SEER2

 + 1.12 x SEER 

• Heating and cooling equipment (including the air handler) shall be sized using the procedures 

published by the Air Conditioning Contractors of America (ACCA). (See 

www.accaconference.com/Merchant2/merchant.mv?Screen=CTGY&Store_Code=ACCOA&Cat

egory_Code=M.) 

• The Benchmark shall not have a whole-house fan. 

• If the Prototype actively controls relative humidity, then the Benchmark shall include a standalone dehumidifier with an energy factor of 1.1 liters/kWh (EPA 2006). Sensible heat generated 

by the dehumidifier shall be added to the cooling load. 

• The Benchmark air handler shall have power consumption equal to 0.00055 kW/cfm. 

The Benchmark shall include an air distribution system with the properties listed in Table 6. The location 

of the ductwork in the Benchmark is based on the type of foundation used for the Prototype. If the 

simulation tool does not permit the input of duct specifications to this level of detail, then two values (one 

for heating, one for cooling) of seasonal distribution system efficiency (DSE) shall be estimated and 

applied to the heating and cooling system efficiencies to represent typical losses from ducts. The DSE 

values shall be determined using Table 6 and the procedures in the Draft ASHRAE Standard 152P 

(ASHRAE 2001). A spreadsheet developed by Lawrence Berkeley National Laboratory (LBNL) and 

modified by NREL is posted on the Building America Web site to assist with this calculation. 

Table 5. Benchmark Space Conditioning Equipment Efficiencies 

Prototype Equipment Function Benchmark Space Conditioning Device 

Gas or Oil Fired Furnace Heating 78% AFUE Gas Furnace 

Mobile Home Furnace Heating 75% AFUE Gas Furnace 

Gas or Oil Fired Boiler (Except Gas Steam) Heating 80% AFUE Gas Boiler 

Gas Steam Boiler Heating 75% AFUE Gas Steam Boiler 

Gas Space Heater Heating 74% AFUE Gas Space Heater 

Other Non-Electric Boiler Heating 80% AFUE Gas Boiler 

Other Non-Electric Heating Heating 78% AFUE Gas Furnace 

Electric or No System Heating 6.8 HSPF Air Source Heat Pump 

Air Source Heat Pump (Split) Heating/Cooling 6.8 HSPF Air Source Heat Pump 

Air Source Heat Pump (Package) Heating/Cooling 6.6 HSPF Air Source Heat Pump 

8
Prototype Equipment Function Benchmark Space Conditioning Device 

Split System Air Conditioner Cooling 10 SEER Air Conditioner 

Single Package Air Conditioner Cooling 9.7 SEER Air Conditioner 

Room Air Conditioner Cooling 9.0 EER Room Air Conditioner 

Other Type or No Air Conditioner Cooling 10 SEER Air Conditioner 

Table 6. Duct Locations and Specifications for the Benchmark

Benchmark Duct Specification Prototype 

Foundation Type One-Story Two-Story or Higher 

Supply Duct Surface Area (ft2) All 0.27 x FFAa 0.20 x FFA 

Return Duct Surface Area (ft2) All 0.05 x Nreturns x FFA 

(Maximum of 0.25 x FFA) 

0.04 x Nreturns x FFA 

(Maximum of 0.19 x FFA) 

Supply Duct Insulation 

(Conditioned Space) All R-3.3 

Return Duct Insulation 

(Conditioned Space) All None 

Supply/Return Duct Insulation 

(Unconditioned Space) All R-5.0 

Duct Material All Sheet Metal 

15% of Air Handler Flow (7% Supply, 3% Return, 5% Air Handler) 

(Percentage lost to each space equal to percentage of duct area in that 

space, as specified below. 50% of flow imbalances between an 

unconditioned basement and living space shall be made up by outside 

air, with the rest caused by direct air movement between the basement 

and living space.) 

Duct Leakage 

(Inside + Outside) All 

Slab-on-grade or 

Raised floor 100% Atticb 65% Atticb

, 35% Conditioned Space 

65% Crawl space, 35% Conditioned 

Space Supply Duct Location Crawl space 100% Crawl space 

Basement 100% Basement 65% Basement, 35% Conditioned 

Space 

Slab-on-grade or 

Raised floor 100% Atticb 100% Atticb

Crawl space 100% Crawl space 100% Crawl space Return Duct and Air Handler 

Location 

Basement 100% Basement 100% Basement 

a

 Finished floor area (ft2) 

b If the Prototype does not have an attic, then this percentage of duct leakage in the Benchmark is assumed to be in 

an attached garage. If the Prototype does not have an attached garage, then the leakage is assumed to be in 

conditioned space.

Domestic Hot Water 

The assumptions in Tables 7 and 8 shall be made for the domestic hot-water system in the Benchmark. 

Both storage and burner capacity are determined using the guidelines recommended by ASHRAE in the 

HVAC Applications Handbook (ASHRAE 1999); these are based on the minimum capacity permitted by 

the Department of Housing and Urban Development (HUD) and the Federal Housing Administrations 

(FHA) (HUD 1982). Energy factor is the NAECA minimum for the corresponding fuel type and storage 

capacity (DOE 2002a). An example set of DHW specifications based on a typical three-bedroom, twobathroom Prototype is shown in Table 9. The “Appliance and DHW” spreadsheet developed by NREL 

9
automates many of the equations discussed in the following paragraphs and can be downloaded from the 

Building America Web site (http://www.eere.energy.gov/buildings/building_america/pa_resources.html). 

Table 7. Characteristics of Benchmark Domestic Hot-Water System 

Water Heater Fuel Type in Prototype 

Electric Gas 

Storage Capacity (V) (Gallons) See Table 8 See Table 8 

Energy Factor (EF) 0.93 – (0.00132 x V) 0.62 – (0.0019 x V) 

Recovery Efficiency (RE) 0.98 0.76 

Burner Capacity See Table 8 See Table 8 

Hot-water Set-Point 120°F 

Same as Prototypea Fuel Type 

Tank Location Same as Prototype 

a If the Prototype does not have a DHW system, or the hot-water system uses solar energy or a fuel other than gas or 

electricity, the Benchmark shall use the same fuel for water heating as that used for space heating. 

Table 8. Benchmark DHW Storage and Burner Capacity (ASHRAE 1999) 

# Bedrooms 1 2 3 4 5 6 

# Bathrooms All ≤1.5 2-2.5 ≥3 ≤1.5 2-2.5 ≥3 ≤1.5 2-2.5 ≥3 All All 

Gas 

 Storage (gal) 20 30 30 40 30 40 40 40 40 50 50 50 

 Burner (kBtu/hr) 27 36 36 36 36 36 38 36 38 38 47 50 

Electric 

 Storage (gal) 20 30 40 50 40 50 50 50 50 66 66 80 

 Burner (kW) 2.5 3.5 4.5 5.5 4.5 5.5 5.5 5.5 5.5 5.5 5.5 5.5

Table 9. Example Characteristics of Benchmark Domestic Hot-Water System Based on a 

Prototype with Three Bedrooms and Two Bathrooms 

Water Heater Fuel Type in Prototype 

Electric Gas 

Storage Capacity (V) (Gallons) 50 40 

Energy Factor (EF) 0.86 0.54 

Recovery Efficiency (RE) 0.98 0.76 

Burner Capacity 5.5 kW 36,000 Btu/hr 

Supply Temperature 120°F 

Fuel Type Same as Prototype 

Tank Location Same as Prototype 

NREL has also developed a spreadsheet that calculates the correct DHW inputs for the TRNSYS 

computer program, including standby heat loss coefficient (UA). The spreadsheet also has a 

comprehensive set of inputs and outputs that can be used to help calculate DHW properties for the 

Prototype house (Burch 2004). It can be found on the Building America Web site in the section for 

building scientists (http://www.eere.energy.gov/buildings/building_america/pa_resources.html). 

Four major end uses are identified for domestic hot water: showers, sinks, dishwasher, and clothes 

washer. The average daily water consumption by end use is shown in Table 10. For showers and sinks, 

the specified volume is the combined hot and cold water. This allows hot-water use to fluctuate 

10
depending on the cold water (mains) temperature.2 Hot-water usage for the clothes washer and 

dishwasher were estimated based on several scientific references studied by NREL. For showers and 

sinks, the water usage is based on the average of three domestic hot-water studies (Christensen, et. al. 

2000, Burch and Salasovich 2002, and CEC 2002). The relationship between the number of bedrooms 

and hot-water usage was derived from the 1997 Residential Energy Consumption Study (RECS) (DOE 

1999). This relationship also applies to machine energy for certain appliances, which will be discussed 

later in this report. 

Table 10. Domestic Hot-water Consumption by End Use 

End Use 

End-Use 

Water 

Temperature 

Water Usage Latent Heat Gain 

Clothes Washer N/A 7.5 + 2.5 x Nbr gal/day 

(Hot Only) 

0* 

Dishwasher N/A 2.5 + 0.833 x Nbr gal/day 

(Hot Only) 

0* 

Shower 105°F 14.0 + 4.67 x Nbr gal/day 

(Hot + Cold) 

777 + 259 x Nbr Btu/day 

(0.7 + 0.23 x Nbr pints/day) 

Bath 105°F 3.5 + 1.17 x Nbr gal/day 

(Hot + Cold) 

0** 

Sinks 105°F 12.5 + 4.16 x Nbr gal/day 

(Hot + Cold) 

0** 

* Latent heat gains from appliances are included in the section entitled “Appliances and 

Miscellaneous Electric Loads.” 

** Negligible compared to showers. 

Hourly hot-water use profiles for individual hot-water end uses are shown in Figures 6-10. For software 

tools that do not accept this level of detail, the combined hourly hot-water profile may be used, as shown 

in Figure 11. The numerical values for normalized hourly hot-water use can be found in the Building 

America Analysis Spreadsheet. 

This combined hourly profile is based on a 1990 study conducted by Becker and Stogsdill (Becker 1990), 

which included hot-water data from several earlier studies. The profiles for the clothes washer and 

dishwasher are based on the electrical end-use measurements in the ELCAP study conducted in the 

Pacific Northwest by the Bonneville Power Administration in the 1980s (Pratt et al 1989). It is assumed 

that the normalized hourly profiles for electricity and hot water are the same for these two appliances. 

The shower and sink profile was derived by subtracting the hourly clothes washer and dishwasher hotwater consumption from the combined hourly hot-water usage for a three-bedroom house in Memphis, 

Tennessee. 

 

2

 The clothes washer in the Prototype may also consume a variable amount of hot water depending on mains 

temperature if it uses a thermostatic control valve to adjust the proportion of hot and cold water necessary to 

maintain a certain wash temperature. However, the Benchmark clothes washer does not have this feature. 

11
0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.10

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour of Day

Fraction of Total Daily Usage

Figure 6. Clothes washer hot-water use profile 

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour of Day

Fraction of Total Daily Usage

Figure 7. Dishwasher hot-water use profile 

12
Figure 8. Shower hot-water use profile 

Figure 9. Bath hot-water use profile 

13
Figure 10. Sink hot-water use profile 

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour of Day

Fraction of Total Daily Usage

Figure 11. Combined domestic hot-water use profile 

The mains water temperature for a typical house varies significantly depending on the location and time 

of year. The following equation, based on TMY2 data for the location of the Prototype, shall be used to 

determine the daily mains water temperature for both the Benchmark and the Prototype: 

Equation 4: Tmains = (Tamb,avg + offset) + ratio * (ΔTamb,max / 2) * sin (0.986 * (day# - 15 - lag) - 90)

where 

Tmains = mains (supply) temperature to domestic hot-water tank (°F) 

Tamb,avg = annual average ambient air temperature (°F) 

14
ΔTamb,max = maximum difference between monthly average ambient 

 temperatures (e.g., Tamb,avg,july – Tamb,avg,january) (°F) 

0.986 = degrees/day (360/365) 

day# = Julian day of the year (1-365) 

offset = 6°F 

ratio = 0.4 + 0.01 (Tamb,avg – 44) 

lag = 35 – 1.0 (Tamb,avg – 44). 

This equation is based on analysis by Christensen and Burch of NREL using data for multiple locations, 

as compiled by Abrams and Shedd (Abrams 1996), Florida Solar Energy Center (Parker 2002), and 

Sandia National Laboratories (Kolb 2003). The offset, ratio, and lag factors were determined by fitting 

the available data. The climate-specific ratio and lag factors are consistent with water pipes being buried 

deeper in colder climates. 

In order for the constant terms in the ratio and lag factors to be representative of an average climate, the 

data fitting was done relative to a nominal Tamb,avg = 44°F. The lag is relative to ambient air temperature, 

and Tamb,minimum is assumed to occur in mid-January (day# = 15). The choices for these nominal values are 

not critical, because although different assumptions would change the constant terms in the ratio and lag

factors, the coefficients would also change, so the prediction of Tmains values would be unchanged. For 

models that use average monthly mains temperature, day# in Equation 4 shall be calculated using 

Equation 5. 

Equation 5: day# = 30 * month# - 15 , 

 where month# = month of the year (1–12). 

An example using Equations 4 and 5 to determine the monthly mains temperature profile for Chicago, 

Illinois, is shown in Figure 12. 

Using TMY2 data for CHICAGO, IL

0

10

20

30

40

50

60

70

80

1 2 3 4 5 6 7 8 9 10 11 12

Month

Temperature (°F) & 

Gallons/day

T ambient

T mains

DHW gal/day

BA - Monthly Mains Water Temperature and DHW Usage

Figure 12. Mains temperature profile for Chicago 

15
Air Infiltration and Ventilation 

The hourly natural air change rate for the Benchmark shall be calculated based on the Specific Leakage 

Area (SLA) determined using Equation 6: 

 Equation 6: SLA = ELA/CFA = 0.00057, 

where ELA = effective leakage area (ft2

), defined as the amount of open area 

that would result in the same total air exchange as the actual 

leakage area of the house at a pressure of 4 Pa 

 CFA = conditioned floor area (ft2

) 

When specifying natural infiltration for a Benchmark with either a directly or indirectly conditioned 

basement, the SLA shall be adjusted to account for the in-ground portions of the walls of the conditioned 

basement. Equation 7 shall be used to make this adjustment. 

 Equation 7: SLAoverall = [(CFAbsmt* SLAbsmt) + (CFAa-g* SLAa-g)] / [CFAtotal] , 

 

 where 

 SLA = ELA (ft2

) / CFA (ft2) 

 SLAa-g = SLAstd (where subscript ‘a-g’ indicates above-grade or exposed) 

 SLAbsmt = SLAstd*(above-grade basement wall area)/(total basement wall area) 

 SLAstd = 0.00057 

This can be calculated by zone, applying SLAbsmt to the basement zone and SLAstd to the above-grade 

zone of the Benchmark and treating the energy balances separately for each zone. It can also be done by 

applying SLAoverall to the combined spaces if the Benchmark is modeled as a single zone. 

Additional air exchange due to mechanical ventilation shall be calculated assuming a balanced ventilation 

system with the same ventilation rate used for the Prototype, up to a maximum value consistent with the 

rate recommended by ASHRAE Standard 62.2. Ventilation air shall be added to the natural infiltration 

rate assuming no interactive effects and no heat recovery. The ventilation fan energy use for the 

Benchmark shall be calculated using a fan efficiency of 0.50 W/cfm. 

Note that finished floor area is used in these equations instead of conditioned floor area. We believe that 

finished floor area more accurately represents the area that occupants use in their daily activities (see also 

the treatment of lighting and plug loads). 

In addition to whole-house ventilation, the Benchmark shall include a kitchen range hood and a 

spot ventilation fan in each bathroom. The flow rates of each fan shall be the same as the 

Prototype, and the efficacy for each fan shall be 0.50 W/cfm. The kitchen range hood is assumed 

to operate 30 minutes per day, and each bathroom fan is assumed to operate 60 minutes per day. 

Lighting Equipment and Usage 

The total annual hard-wired lighting use for the Benchmark is determined using Equations 8-10. These 

equations are derived from data for both single-family and multi-family housing documented in a lighting 

study conducted by Navigant for DOE (Navigant Consulting 2002). 

Equation 8: Interior hard-wired lighting = 0.8*(FFA * 0.8 + 455) kWh/yr , 

Equation 9: Garage lighting = 100 kWh/yr , 

Equation 10: Exterior lighting = 250 kWh/yr , 

16
Annual hard-wired indoor lighting, in kilowatt-hours, represents approximately 80% of all indoor lighting 

and is expressed as a linear function of finished house area relative to a constant base value. Garage and 

exterior lighting are treated as constants. When combined with plug-in lighting (discussed in the next 

section), the total interior lighting calculated using this equation is in the middle range of residential 

lighting energy use found in other lighting references, as shown in Figure 13, including Huang and Gu 

(2002), the 1993 RECS (DOE 1996), a Florida Solar Energy Center study (Parker et al 2000), default 

lighting for Visual DOE software (Eley 2002), a lighting study conducted by Navigant for DOE 

(Navigant Consulting 2002), and two other studies in Grays Harbor, Washington (Manclark and Nelson 

1992), and Southern California Edison (SCE 1993). 

0

500

1000

1500

2000

2500

3000

3500

4000

4500

5000

0 500 1000 1500 2000 2500 3000 3500 4000

House Size (ft2)

Annual Indoor Lighting (kWh)

Benchmark

Huang & Gu

FSEC

Visual DOE

RECS 93

Navigant

Grays Harbor

SCE

Figure 13. Comparison of Benchmark lighting equation to other references 

The Benchmark lighting budget is based on an assumption that 86% of all lamps are incandescent, and the 

remaining 14% are fluorescent. This is consistent with the source data set from 161 homes monitored by 

Tacoma Public Utilities (TPU) for the Bonneville Power Administration, which was the basis for the 

Navigant study. Although the core data set used in this study is the most complete and comprehensive 

residential lighting data set that we have identified, it is nevertheless limited in terms of geographic 

location, number of homes, length of study, percent of fixtures monitored, and type of homes studied. 

The Navigant report includes an appendix providing information about the characteristics of the homes 

monitored in the TPU study. 

If a comprehensive lighting plan has not been developed for the Prototype house, and only fluorescent 

and incandescent lamps are installed, then a simplified approach may be used to estimate energy savings 

compared to the Benchmark using Equation 11. This equation is based on an assumption that the 

efficacies of incandescent and fluorescent light fixtures are the same in the Prototype as they were in the 

TPU study, and that fluorescent lighting is distributed equally among all hard-wired fixtures, including 

garage and exterior lights. 

17
 Equation 11: Prototype hard-wired lighting (kWh/yr) = LB*(1.12*FI + 0.279*FF) 

where LB = hard-wired interior, exterior, or garage lighting for the Benchmark from 

Equation 8, 9, or 10 (kWh/yr) 

B

 FI = fraction of hard-wired lamps in the Prototype that are incandescent 

 FF = fraction of hard-wired lamps in the Prototype that are fluorescent 

The annual average normalized daily load shape for interior lighting use is shown in Figure 14, based on a 

draft LBNL report by Huang and Gu (2002). This load shape is also used for exterior and garage lighting. 

Monthly variations in load shape and lighting energy use due to changes in the length of days can be 

accounted for, as long as the variation is applied to all the simulation models and total annual energy use 

remains the same. 

0

0.02

0.04

0.06

0.08

0.1

0.12

0.14

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

fraction of daily total

Figure 14. Interior lighting profile (Built up from detailed profiles) 

Energy savings may be calculated on the basis of a number of usage variations, depending on the 

capability of the modeling tool. Variations include day types (weekday vs. weekend), occupancy types 

(day-use vs. non-day-use or “nuclear” vs. “yuppie”), season (summer vs. winter), and room types (living 

area vs. bedroom area). 

Individual normalized profiles can be “rolled up” to various levels of detail appropriate to the simulation 

model. An example of one detailed set of profiles developed by NREL is shown in Figure 15. Other 

profiles are included in spreadsheets available on the Building America Web site 

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

18
Annual Average Lighting Profile

Day-Use, Living Areas, Weekdays, by Season

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

fraction of maximum

Ltg-DU-LR-WD-WI

Ltg-DU-LR-WD-SU

Ltg-DU-LR-WD-SF

Figure 15. Example of a detailed lighting profile (expressed as fraction of peak daily 

lighting energy) 

The lighting plans for the Prototype and Benchmark should be based on the same hours of operation 

unless the Prototype includes specific design measures that alter the operating time of the lighting system, 

such as occupancy sensors, dimming switches, or a building automation system. Average operating hours 

estimated in the Navigant study are generally a good starting point (Table 11), but there may be 

substantial differences between typical lighting designs found in the TPU sample and the lighting design 

developed in conjunction with the architecture of the Prototype. The analyst must ultimately apply good 

engineering judgment when specifying operating hours for the lighting system. 

 

Table 11. Average Lighting Operating Hours for Common Room Types in a Sample of 

161 Homes in the Pacific Northwest 

Room Type Operation 

(Hours/Day/Room) Room Type Operation (Hours/Day/Room) 

Bathroom 1.8 Kitchen 3.0 

Bedroom 1.1 Living Room 2.5 

Closet 1.1 Office 1.7 

Dining Room 2.5 Outdoor 2.1 

Family Room 1.8 Utility Room 2.0 

Garage 1.5 Other 0.8 

Hall 1.5 

Source: Navigant Consulting 2002

Appliances and Miscellaneous Electric Loads 

As with lighting, several characteristics must be defined for appliances and miscellaneous electric loads 

(MELs): the amount of the load, the schedule of the load, the location of the load, the fraction of the load 

that becomes a sensible load, and the fraction of the load that becomes a latent load. Though the internal 

load may be treated as an aggregate, the energy consumption for each end use must be considered 

separately. A breakdown of annual energy consumption and associated internal loads for major 

appliances and other equipment is shown in Table 12. Not all of the energy consumed by appliances is 

converted into internal load; much of the waste heat is exhausted to the outside or released down the drain 

in the form of hot water. The appliance loads were derived by NREL from EnergyGuide labels, a 

19
Navigant analysis of typical models available on the market that meet current NAECA appliance 

standards, and several other studies. 

For a house of typical size (1000-3000 ft2

), the loads from the occupants and most appliances are assumed 

to be a function of the number of bedrooms and the finished floor area. The exceptions are the 

refrigerator and certain miscellaneous gas and electric loads, which are assumed to be constant regardless 

of the number of bedrooms. The general relationship between appliance loads, number of bedrooms, and 

house size, was derived empirically from the 2001 RECS. The sensible and latent load fractions were 

developed based on engineering analysis and judgment. 

Miscellaneous loads are broken into variable electric loads and fixed gas and electric loads. By 

definition, energy savings are not calculated for improvements to fixed loads because an analysis 

methodology has not yet been established. However, NREL has developed a methodology for calculating 

energy savings associated with the most common miscellaneous electric loads encountered in a typical 

house, which we refer to as variable MELs. Approximately 100 MELs in this category are listed in Table 

13. If the analyst chooses to use anything other than the Benchmark MEL values for the Prototype, he or 

she must use the MEL Analysis Spreadsheet for new construction posted on the Building America Web 

site (http://www.eere.energy.gov/buildings/building_america/pa_resources.html) to calculate energy 

savings, latent and sensible loads, and the split between standby and operating energy. This spreadsheet 

only allows the analyst to change the quantity and the operating and standby power levels of MELs in the 

Prototype. Operating hours cannot be changed, but a lower “effective” power draw may be used if 

occupancy sensors or other controls are used to turn off power to MELs that are not in use. In addition, 

only those MELs that are installed or provided by the builder may be included in the energy savings 

analysis. The remaining MELs in the Prototype revert to the default values used for the Benchmark. 

References for the typical MEL characteristics used in the calculations are documented in the spreadsheet. 

Table 12. Annual Appliance and Equipment Loads for the Benchmark3

Appliance Electricity 

(kWh/yr) 

Natural Gas 

(therms/yr) 

Sensible Load 

Fraction 

Latent Load Fraction

Refrigerator 669 1.00 0.00 

Clothes Washer (3 ft3 drum) 52.5 + 17.5 x Nbr 0.80 0.00 

Clothes Dryer (Electric) 418 + 139 x Nbr 0.15 0.05 

Clothes Dryer (Gas) 38 + 12.7 x Nbr 26.5 + 8.8 x Nbr

1.00 (Electric) 

0.10 (Gas) 

0.00 (Electric) 

0.05 (Gas) 

Dishwasher (8 place 

settings) 103 + 34.3 x Nbr 0.60 0.15 

Range (Electric) 302 + 101 x Nbr 0.40 0.30 

Range (Gas) 22.5 + 7.5 x Nbr 0.30 0.20 

Plug-In Lighting 0.2*(FFA * 0.8 + 455)] 1.00 0.00 

Variable Miscellaneous 

Electric Loads (MELs) 

1231 +194 x Nbr+ 

0.316 x FFA 0.81 0.02 

Fixed Miscellaneous Loads 

(Gas/Electric) 360 11.5 0.13 0.25 

Fixed Miscellaneous Loads 

(All-Electric) 697 0.13 0.25 

 

3 End-use loads in this table include only energy used within the machine. Associated domestic hot water use is 

treated separately (see “Domestic Hot Water”). The Building America Analysis Spreadsheet on the Building 

America Web site (http://www.eere.energy.gov/buildings/building_america/pa_resources.html) can assist with the 

calculation of this split for an energy-efficient clothes washer or dishwasher based on the Energy Guide label. 

20
Table 13. Benchmark Annual Energy Consumption for Miscellaneous Electric and Gas 

Loads. (three-bedroom house, 1920 ft2

) 

Miscellaneous Electric 

Load 

Avg 

Units/ 

Hshld 

Energy/ 

Unit 

kWh/yr 

Energy/ 

Hshld 

kWh/yr 

Miscellaneous Electric Load 

Avg 

Units/ 

Hshld 

Energy/ 

Unit 

kWh/yr 

Energy/ 

Hshld 

kWh/yr 

Hard-Wired Home Office 

Fan (Ceiling) 1.400 50.0 70.0 Laptop PC (Plugged In) 0.152 47.0 7.1 

Air Handler Standby Losses 0.800 67.2 53.8 Desktop PC w/ Speakers 0.592 143.9 85.2 

HVAC Controls 1.000 20.3 20.3 PC Monitor 0.592 119.8 70.9 

Home Security System 0.187 195.1 36.5 Printer (Laser) 0.049 92.5 4.5 

Ground Fault Circuit Interrupter 3.850 6.2 23.9 Printer (Inkjet) 0.118 39.0 4.6 

Sump Pump 0.099 40.0 3.9 Dot Matrix Printer 0.030 115.0 3.5 

Heat Lamp 0.010 13.0 0.1 DSL/Cable Modem 0.200 17.6 3.5 

Garage Door Opener 0.266 35.0 9.3 Scanner 0.050 49.0 2.4 

Carbon Monoxide Detector 0.260 17.5 4.6 Copy Machine 0.020 25.0 0.5 

Smoke Detectors 0.840 3.5 2.9 Fax Machine 0.030 326.3 9.8 

Garbage Disposal 0.404 10.0 4.0 Bathroom 

Doorbell 0.670 44.0 29.5 Hair Dryer 0.837 0.6 0.5 

Home Entertainment Curling Iron 0.532 1.0 0.5 

First Color TV 0.986 215.5 212.5 Electric Shaver 0.470 12.8 6.0 

Second Color TV 0.669 112.7 75.4 Electric Toothbrush Charger 0.118 19.3 2.3 

Third Color TV 0.296 66.7 19.7 Garage & Workshop 

Fourth Color TV 0.104 52.1 5.4 Auto Block Heater 0.019 250.0 4.8 

Fifth or More Color TV 0.028 45.8 1.3 Lawn Mower (Electric) 0.059 42.9 2.5 

First VCR 0.876 71.3 62.5 Heat Tape 0.030 100.0 3.0 

Second VCR 0.320 68.9 22.1 Kiln 0.020 50.0 1.0 

Third or More VCR 0.072 68.6 4.9 Pipe and Gutter Heaters 0.010 53.0 0.5 

DVD Player 0.472 50.1 23.7 Shop Tools 0.130 26.4 3.4 

Video Gaming System 0.631 20.4 12.9 Other 

Clock Radio 1.260 14.9 18.8 Humidifier 0.150 100.0 15.0 

Boombox / Portable Stereo 0.670 16.8 11.3 Water Bed 0.066 1068.0 70.5 

Compact Stereo 0.460 112.3 51.6 Sm Freshwater Aquarium (5-20 gal) 0.024 105.0 2.5 

Component / Rack Stereo 0.730 153.0 111.7 Md Freshwater Aquarium (20-40 gal) 0.024 180.0 4.3 

Power Speakers 0.296 24.4 7.2 Lg Freshwater Aquarium (40-60 gal) 0.024 340.0 8.1 

Subwoofer 0.099 68.3 6.7 Small Marine Aquarium (5-20 gal) 0.002 245.0 0.6 

Radio 0.493 9.1 4.5 Medium Marine Aquarium (20-40 gal) 0.002 615.0 1.5 

Equalizer 0.049 14.7 0.7 Large Marine Aquarium (40-60 gal) 0.002 740.0 1.8 

Satellite Dish Box 0.202 131.7 26.6 Vacuum Cleaner (Upright) 0.946 31.0 29.3 

Cable Box 0.637 152.7 97.3 Clock 0.956 26.0 24.8 

Kitchen Cordless Phone 0.601 23.2 13.9 

Microwave 0.933 135.1 126.1 Cell Phone Charger 0.450 77.4 34.8 

Freezer 0.323 935.0 302.0 Electric Blanket 0.286 120.0 34.3 

Extra Refrigerator 0.179 1100.0 196.9 Answering Machine 0.650 33.5 21.8 

Coffee Maker (Drip) 0.685 99.3 68.0 Battery Charger 0.437 14.8 6.5 

Coffee Maker (Percolator) 0.167 65.0 10.9 Fan (Portable) 0.946 11.3 10.7 

Toaster Oven 0.345 50.0 17.3 Air Cleaner 0.217 65.7 14.2 

Toaster 0.837 43.7 36.6 Vacuum Cleaner (Cordless) 0.207 36.5 7.6 

Waffle Iron 0.325 25.0 8.1 Heating Pads 0.670 3.0 2.0 

Blender 0.788 7.0 5.5 Surge Protector / Power Strip 0.360 3.9 1.4 

Can Opener 0.650 3.0 2.0 Timer (Lighting) 0.280 20.1 5.6 

Electric Grill 0.010 180.0 1.8 Timer (Irrigation) 0.050 45.2 2.3 

Hand Mixer 0.877 2.0 1.8 Iron 0.847 53.0 44.9 

Electric Griddle 0.256 6.0 1.5 Baby Monitor 0.100 22.8 2.3 

Popcorn Popper 0.305 5.0 1.5 Fixed MELs

Espresso Machine 0.069 19.0 1.3 Pool Heater (Electric) 0.004 2300.0 9.2 

Instant Hot-water Dispenser 0.006 160.0 1.0 Pool Pump (Electric) 0.066 2228.3 147.1 

Hot Plate 0.236 30.0 7.1 Hot Tub / Spa Heater (Electric) 0.056 1704.0 95.4 

Food Slicer 0.414 1.0 0.4 Hot Tub / Spa Pump (Electric) 0.094 460.0 43.2 

Electric Knife 0.374 1.0 0.4 Well Pump (Electric) 0.129 400.0 51.6 

Broiler 0.010 80.0 0.8 Coral Reef Aquarium (Electric) 0.001 4500.0 3.6 

Deep Fryer 0.148 20.0 3.0 Gas Fireplace 0.035 1760.0 60.9 

Bottled Water 0.010 300.0 3.0 Gas Grill 0.029 879.0 25.5 

Trash Compactor 0.010 50.0 0.5 Gas Lighting 0.005 557.0 2.9 

Slow Cooker / Crock Pot 0.581 16.0 9.3 Pool Heater (Gas) 0.024 6506.0 158.7 

Hot Tub / Spa Heater (Gas) 0.038 2374.0 90.2 

Other 1.000 9.4 9.4 

Total MEL Load 3117 

21
The hourly, normalized load shape for combined residential equipment use is shown in Figure 16, and is 

based on the ELCAP study of household electricity use in the Pacific Northwest (Pratt et al 1989). In 

most situations, this profile is adequate for simulating all electric and gas end-uses except space 

conditioning and hot water. However, because some individual end-use profiles are nearly constant (such 

as refrigerator and transformer loads) and some are highly dependent on time of day (such as the range 

and dishwasher), we have also developed a series of normalized hourly profiles for major appliances and 

plug loads, shown in Figures 17-22. Numerical values associated with these profiles can be found in the 

Building America Analysis Spreadsheet posted on the Building America Web site 

(http://www.eere.energy.gov/buildings/building_america/pa_resources.html). The hourly profiles for 

machine energy usage in the clothes washer and dishwasher are identical to those provided earlier in the 

section on DHW (see Figures 6-7). The profile for plug-in lighting is the same as the profile for hardwired lighting presented in Figure 14. 

All hourly end-use profiles were taken from the ELCAP study, except the profile for “Other Appliance 

and Plug Loads,” which was derived by subtracting the energy consumption profiles for the major 

appliances from the combined profile for all equipment, assuming an all-electric, 1800-ft2

, three-bedroom 

house in Memphis, Tennessee. Internal sensible and latent loads from appliances and plug loads shall be 

modeled using the same profile used for end-use consumption. Appliance loads may be modeled in either 

the living spaces or bedroom spaces, depending on their location in the Prototype. 

Large end uses in the Prototype that are not part of typical houses (such as swimming pools, Jacuzzis, and 

workshops) are not included in the models for either the Prototype or the Benchmark. The efficiency of 

these end uses should be addressed in a separate analysis. 

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.1

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour of Day

Fraction of Total Daily Usage

Figure 16. Total combined residential equipment profile (Pratt et al 1989) 

22
0.00

0.01

0.02

0.03

0.04

0.05

0.06

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour of Day

Fraction of Total Daily Usage

Figure 17. Refrigerator normalized energy use profile (Pratt et al 1989) 

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0.10

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour of Day

Fraction of Total Daily Usage

Figure 18. Clothes washer normalized machine energy use profile (Pratt et al 1989) 

23
0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0.08

0.09

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour of Day

Fraction of Total Daily Usage

Figure 19. Clothes dryer normalized energy use profile (Pratt et al 1989) 

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour of Day

Fraction of Total Daily Usage

Figure 20. Dishwasher normalized energy use profile (Pratt et al 1989) 

24
0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0.16

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour of Day

Fraction of Total Daily Usage

Figure 21. Range/oven normalized energy use profile (Pratt et al 1989) 

0.00

0.01

0.02

0.03

0.04

0.05

0.06

0.07

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24

Hour of Day

Fraction of Total Daily Usage

Figure 22. Other appliance and plug load normalized energy use profile 

25
Site Generation 

A review of data from the Energy Information Administration (DOE 2001a) shows that there is rarely any 

site electricity generation in a 1990s vintage house. This is a reflection of the low market penetration of 

site electricity systems. Therefore, all electricity is purchased from the local utility in the Benchmark. As 

costs for photovoltaic systems and other site electricity systems continue to decline, they are expected to 

begin to make a significant contribution toward meeting residential energy needs by the year 2020. 

Therefore, site electricity generation must be included in the whole-house energy performance analysis of 

the Prototype. 

Modeling the Prototype 

The Prototype is modeled either as-designed or as-built, depending on the status of the project. All 

parameters for the Prototype model shall be based on final design specifications or measured data, with 

the following exceptions and clarifications: 

• Any house characteristics that are unknown and are not part of the package of energy efficiency 

improvements shall be the same as the Benchmark. 

• The effective leakage area for the Prototype shall be calculated based on blower door testing 

conducted in accordance with ASTM E779. If the whole-house simulation tool cannot calculate 

hourly infiltration based on effective leakage area, an annual average natural infiltration rate may 

be used based on the guidelines in ASHRAE Standard 119 (ASHRAE 1988), Section 5, and 

ASHRAE Standard 136 (ASHRAE 1993), Section 4. It is recommended that blower door 

measurements be supplemented with tracer gas testing when possible. 

• If the Prototype does not have a cooling system, but there is a non-zero cooling load, then the 

Prototype shall be modeled assuming a standard 10 SEER air conditioner connected to the 

heating ducts. If the Prototype does not have a duct system for heating, the air conditioner shall 

be modeled as a ductless 10 SEER room air conditioner. 

• Mechanical ventilation shall be combined with natural infiltration in accordance with Section 4.4 

of ASHRAE Standard 136 to determine an approximate combined infiltration rate. 

• If the actual EER for the Prototype is not readily available, Equation 12 may be used to make an 

approximate conversion from SEER to EER (Wassmer 2003): 

 Equation 12: EER = -0.02 x SEER2

 + 1.12 x SEER 

• The installation of energy-saving appliances or other equipment may reduce hot-water 

consumption for certain end uses, reduce the internal sensible and latent loads, or affect the 

hourly operating profiles. Energy savings calculations for the Prototype must take these effects 

into account using operating conditions based on rules developed for DOE residential appliance 

standards (DOE 2003), and the actual performance characteristics of the appliances. The number 

of cycles per year specified in the appliance standard for clothes washers is adjusted according to 

the number of bedrooms and the clothes washer capacity, using Equation 13: 

 Equation 13: Clothes washer cycles per year = (392) x (1⁄2+Nbr/6) x 12.5 lb / Wtest , 

where Wtest = maximum clothes washer test load weight found in 10 CFR part 

430, Subpt B, Appendix J1, as a function of the washer capacity in ft3

. 

Nbr = number of bedrooms. 

26
A dryer usage factor (DUF) is applied to the clothes washer cycles to determine the number of 

annual dryer cycles, using Equation 14: 

 

 Equation 14: Clothes dryer cycles per year = DUF x Clothes washer cycles per year , 

 where DUF = 0.84. 

The dishwasher annual operating cycles are similarly calculated, using Equation 15: 

 Equation 15: Dishwasher cycles per year = (215) x (1⁄2 + Nbr/6) . 

The Building America Analysis Spreadsheet posted on the Building America Web site automates 

these calculations, and is strongly recommended for the analysis of water-consuming appliances. 

The spreadsheet includes tabs to help analysts calculate energy savings for efficient clothes 

washers, clothes dryers, and dishwashers. It calculates the split between hot water and machine 

energy based on the EnergyGuide label, estimates dryer energy savings for clothes washers that 

reduce remaining moisture content, adjusts energy use for the assumption that both hot water and 

cold water temperatures for the house are usually different than the test values (140°F and 

60°F/50°F), and adjusts for the type of controls present (thermostatic control valves, boost 

heating, cold water only). Both annual average and monthly average hot-water usage are 

calculated in the spreadsheet. 

• Energy savings for a new range/oven may only be credited if an energy factor has been 

determined in accordance with the DOE test procedures for cooking appliances (DOE 1997). 

Annual energy consumption is then estimated as the product of the energy factor and the annual 

useful cooking energy output as defined in the same test procedure. If the energy factor is 

unknown for a new range/oven, then it shall be assumed that the Prototype energy use for 

cooking is the same as the Benchmark. 

• Modifications to the Benchmark lighting profile and operating hours due to occupancy sensors or 

other controls may be considered for the Prototype, but negative and/or positive effects on space 

conditioning load must also be calculated, assuming 100% of interior lighting energy contributes 

to the internal sensible load. 

• Large end uses that are not part of typical houses (such as swimming pools, Jacuzzis, workshops, 

etc.) shall not be included in the model of the Prototype. The efficiency of these end uses should 

be addressed in a separate analysis. 

• For the Prototype, all site electricity generation is credited regardless of energy source. 

Residential-scale photovoltaic systems, wind turbines, fuel cells, and micro-cogeneration systems 

are all potential sources of electricity generated on the site. An offset must be applied to this 

electricity credit equal to the amount of purchased energy used in the on-site generation process. 

The credit for site generation shall be tracked separately from the whole-house energy analysis 

and reported as a separate line in the summary tables (discussed later in this section). 

Operating Conditions 

The following operating conditions and other assumptions shall apply to both the Prototype house and the 

Benchmark. The operating conditions are based on the cumulative experience of the authors through their 

work on Building America, HERS, Codes and Standards, and other residential energy efficiency 

programs. 

27
• Thermostat set points based on the optimum seasonal temperature for human comfort as defined 

in ASHRAE Standard 55-1992 (ASHRAE 1992). 

Set point for cooling: 76°F with no setup period 

Set point for heating: 71°F with no setback period 

Set point for dehumidification (if controlled): 60% relative humidity 

• The natural ventilation schedule shall be set to reflect windows being opened occasionally. In 

situations where it is a Monday, Wednesday, or Friday and there is a cooling load, windows will 

be opened if the cooling capacity of outdoor air flow can maintain the cooling set point and the 

outdoor enthalpy is below the indoor enthalpy (in humid climates). The natural ventilation rate 

shall be calculated using the Sherman-Grimsrud model. Fifty percent of the maximum open area 

for windows on each facade and on each floor shall be open. Windows are assumed to be closed 

once the indoor temperature drops below 73°F or if the air change rate exceeds 20 ACH. If there 

are local circumstances that would tend to discourage window operation (pollution, high 

humidity, security, community standards, etc.), then it is acceptable to use a more appropriate 

schedule, as long as the same natural ventilation schedule is applied to both the Benchmark and 

Prototype. Mechanical ventilation fans shall be turned off when natural ventilation is being used. 

 

• Interior shading multiplier = 0.7 during the cooling season, and 0.85 during the heating season 

and during swing seasons when both cooling and heating occur. Specific guidelines for defining 

seasons are presented later in this section. 

 

• If needed for the simulation of a particular design, standard event schedules for domestic hot 

water are specified in the Building America DHW Event Schedule Spreadsheets posted on the 

Building America Web site 

(http://www.eere.energy.gov/buildings/building_america/pa_resources.html). The TMY2 site 

must be entered to automatically adjust for climate and seasonal effects. These event schedules 

are only appropriate for standard appliances. Energy-efficient or other non-standard clothes 

washers and dishwashers may require the generation of a new set of event schedules using the 

software DHW-calc developed by Kassel University (http://cms.uni-kassel.de/index.php?id=107). 

Standard input assumptions are documented in the spreadsheets, and should be adjusted based on 

the actual appliance operating characteristics. 

• Internal loads from lighting, appliances, and other equipment were discussed in previous sections. 

These loads are not necessarily the same for the Prototype and the Benchmark; therefore, they are 

not considered operating conditions for the purposes of Building America performance analysis. 

• Annual cycles for clothes washers, dryers, and dishwashers calculated using the Building 

America Analysis Spreadsheet posted on the Building America Web site. 

• The occupancy schedule is defined with the same level of detail as other internal load profiles. 

For typical Building America houses, the number of occupants shall be estimated based on the 

number of bedrooms using Equation 16. 

Equation 16: Number of occupants = 0.5 x Nbr + 1.5 

 where Nbr = Number of bedrooms. 

Sensible and latent gains shall be accounted for separately, and different loads shall be applied in 

different space types, as described in Table 14. The occupant heat gains are based on ASHRAE 

recommendations (ASHRAE 2001). The average hourly occupancy profile is shown in Figure 

23, and an example set of detailed hourly occupancy curves is shown in Figure 24. Detailed 

28
occupancy profiles based on different day and room types are available in spreadsheet format on 

the Building America Web site 

(http://www.eere.energy.gov/buildings/building_america/pa_resources.html). These profiles, 

which were developed by NREL, are based on the basic ASHRAE occupancy schedule combined 

with engineering judgment. 

Table 14. Peak Sensible and Latent Heat Gain from Occupants (ASHRAE 2001) 

Multiple Zones Internal Load 

(Btu/person/hr) 

Living Area Sensible Load 230 

Living Area Latent Load 190 

Bedroom Area Sensible Load 210 

Bedroom Area Latent Load 140 

Internal Load 

(Btu/person/hr) Single Zone 

Sensible Load 220 

Latent Load 164 

Occupancy Profile

daily average - whole house

0.0

0.2

0.4

0.6

0.8

1.0

1

3

5

7

9

11

13

15

17

19

21

23

fraction of total people

Figure 23. Average hourly load profile from occupants for all day-types and family types 

(16.5 hours/day/person total) 

29
Occupancy Profiles

by Day-Type and Space-Type

0.0

0.2

0.4

0.6

0.8

1.0

1

3

5

7

9

11

13

15

17

19

21

23

fraction of total people

Occ-LR-WD Occ-LR-WE

Occ-BR-WD Occ-BR-WE

Figure 24. Detailed hourly load profiles resulting from occupants being in different parts 

of the house on weekdays (WD) and weekends (WE) 

• The internal mass of furniture and contents shall be equal to 8 lbs/ft2 of conditioned floor space. 

For solar distribution purposes, lightweight furniture covering 40% of the floor area shall be 

assumed. 

 

• Weather data shall be based on typical meteorological year (TMY2) data from 1961–19904 or 

equivalent data for the nearest weather station. 

 

• Heating and cooling shall only occur during certain months of the year in accordance with the 

guidelines presented below. Alternate operating profiles may be acceptable with sufficient 

justification. The heating and cooling seasons shall be determined on the basis of the monthly 

average temperatures (MAT) and the 99% (annual, not seasonal) winter and summer design 

temperatures (WDT and SDT, respectively) based on TMY2 data or ASHRAE Fundamentals 

2001 for the nearest location, in accordance with the following procedures: 

Step 1. MAT Basis 

(I) The heating system shall be enabled for a month in which the MAT is less 

than 66°F. 

(II) The cooling system shall be enabled for a month in which the MAT is 

greater than 66°F. 

Step 2. WDT and SDT 

(I) The heating system shall be enabled in December and January if the WDT 

is less than or equal to 59°F, regardless of the outcome in Step 1 above. 

(II) The cooling system shall be enabled in July and August regardless of the 

outcome in Step 1 above. 

Step 3. Swing Season Adjustment 

(I) If, based on Steps 1 and 2 above, there are consecutive months in which the 

cooling system is disabled the first month and enabled the following 

month, then the heating system shall be enabled for the second month. 

 

4 Analytic Studies Division, National Renewable Energy Laboratory 

(http://rredc.nrel.gov/solar/old_data/nsrdb/tmy2/).

30
(II) If, based on Steps 1 and 2 above, there are consecutive months in which the 

heating system is disabled the first month and enabled the following 

month, then the cooling system shall be enabled for the second month. 

Reporting Energy Use and Energy Savings 

Reporting energy use and energy savings in a consistent format is an important component of Building 

America analysis. The following tables shall be supplied with the analysis report for every Building 

America Prototype. 

Table 15 shows an example of a site energy consumption report for a hypothetical Prototype in Virginia, 

along with all relevant base cases. Similar information based on source energy is presented in Table 16, 

along with percent energy savings for each end use. End uses are described in more detail in Table 17. 

The “Percent of End Use” columns in Table 16 show the Prototype energy use for each end use as a 

fraction of the appropriate base case. The “Percent of Total” columns show the contribution of each end 

use toward an overall energy reduction goal. Note that site generation for the Benchmark is always zero. 

Source energy shall be determined using Equation 17. For fuels other than electricity and natural gas 

(such as fuel oil or propane), it is typically not necessary to apply a site to source multiplier. 

Equation 17: Source MBtu = kWh * 3.412 * Me /1000 + therms * Mg / 10 + MBtu * Mo , 

 where Me = 3.16 = site to source multiplier for electricity (DOE 2002b); 

 Mg = 1.02 = site to source multiplier for natural gas (DOE 1995); 

Mo = 1.00 = site to source multiplier for all other fuels. 

Table 15. Example Summary of Site Energy Consumption by End Use Using Building 

America (BA) Research Benchmark 

Annual Site Energy 

BA Benchmark Region Standard Builder Standard BA Prototype 

End Use (kWh) (therms) (kWh) (therms) (kWh) (therms) (kWh) (therms)

Space Heating 11,225 0 11,286 0 11,286 0 4,397 0 

Space Cooling 2,732 0 2,432 0 2,432 0 902 0 

DHW 4,837 0 4,838 0 4,838 0 1,351 0 

Lighting 3,110 3,110 3,110 1,204 

Appliances + Plug 7,646 0 7,646 0 7,646 0 7,436 0 

OA Ventilation 400 400 400 400 

Total Usage 29,950 0 29,712 0 29,712 0 15,690 0 

Site Generation 0 0 0 0 0 0 7,402 0 

Net Energy Use 29,950 0 29,712 0 29,712 0 8,289 0 

31
Table 16. Example Summary of Source Energy Consumption by End Use Using Building 

America Research Benchmark 

Source Energy Savings 

Estimated Annual Source Energy Percent of End-Use Percent of Total 

Benchmark Region Builder Proto BA Reg Bldr BA Reg Bldr 

End Use (MBtu/yr) (MBtu/yr) (MBtu/yr) (MBtu/yr) Base Base Base Base Base Base 

Space Heating 115 116 116 45 61% 61% 61% 23% 23% 23% 

Space Cooling 28 25 25 9 67% 63% 63% 6% 5% 5% 

DHW 50 50 50 14 72% 72% 72% 12% 12% 12% 

Lighting 32 32 32 12 61% 61% 61% 6% 6% 6% 

Appliances + Plug 78 78 78 76 3% 3% 3% 1% 1% 1% 

OA Ventilation 4 4 4 4 0% 0% 0% 0% 0% 0% 

Total Usage 307 304 304 161 48% 47% 47% 48% 47% 47% 

Site Generation 0 0 0 -76 25% 25% 25% 

Net Energy Use 307 304 304 85 72% 72% 72% 72% 72% 72% 

Table 17. End-Use Categories 

End Use Potential Electric Usage Potential Gas Usage 

Gas furnace, gas boiler, gas backup HP supplemental heat, gas 

ignition stand-by 

Space Heating Supply fan during space heating, 

HP, HP supplemental heat, water 

boiler heating elements, water 

boiler circulation pump, electric 

resistance heating, HP crankcase 

heat, heating system auxiliary 

Space Cooling Central split-system A/C, Gas absorption chiller (rare) 

packaged A/C (window or throughthe-wall), supply fan energy during 

space cooling, A/C crankcase 

heat, cooling system auxiliary 

DHW Electric hot-water heater, HP 

water heater, hot-water circulation 

pumps 

Gas hot-water heater 

Lighting Indoor lighting, outdoor lighting None 

Equipment Refrigerator, electric clothes dryer, Cooking, gas clothes dryer 

gas clothes dryer (motor), cooking, 

miscellaneous 

OA Ventilation Ventilation fans, supply air fan 

during ventilation mode 

None 

Site Generation Photovoltaic electric generation None 

Table 18 reports energy savings for individual energy efficiency measures applied to the Prototype, in 

terms of source energy and energy cost. “Source Energy Savings %” is determined by comparing the 

source energy for each measure increment to the source energy for the Benchmark (i.e., the first row). In 

this column, the incremental savings for each measure are added to the savings for all the previous 

measures. The final row of the column is the overall energy savings achieved for the Prototype house. 

When available, actual energy tariffs for the Prototype house shall be used to determine whole-building 

energy costs. Energy cost and measure savings are compared with the Builder Standard Practice 

(representing a real design or set of practices that is currently being used by the builder) rather than with 

32
the Benchmark. This provides an evaluation of the improvements in the performance of the Prototype 

compared with that of homes currently being sold by the builder partner. 

Reporting of peak hourly energy consumption is also encouraged for every Prototype. Peak energy is 

based on the hour with the greatest gas or electric energy consumption during the course of one year, as 

determined by the hourly simulation. 

Table 18. Example Measure Savings Report5

 Using Building America Research 

Benchmark 

National Average Builder Standard (Local Costs) 

Site Energy Est. Source Energy Energy Cost Energy Cost Measure Package 

Increment (kWh) (therms) (MBtu) 

Savings 

(%) ($/yr) Savings (%) ($/yr) 

Savings 

(%) Value ($/yr)

Savings 

($/yr) 

Bldg America 

Benchmark 29950 0 306.9 $ 2,995 $ 2,950 

Regional Std 

Practice 29712 0 304.4 1% $ 2,971 1% $ 2,927 

Builder Std 

Practice (BSP) 29712 0 304.4 1% $ 2,971 1% $ 2,927 

BSP + 

 improved walls 27779 0 284.6 7% $ 2,778 7% $ 2,736 7% $ 190.4 $ 190 

BSP ++ 

 Low-E Windows 25810 0 264.5 14% $ 2,581 14% $ 2,542 13% $ 193.9 $ 384 

BSP ++ 

 Smaller A/C (5 -

> 4 tons) 25420 0 260.5 15% $ 2,542 15% $ 2,504 14% $ 38.4 $ 423 

BSP ++ 

 Inc. Bsmt Wall 

Insulation 25170 0 257.9 16% $ 2,517 16% $ 2,479 15% $ 24.6 $ 447 

BSP ++ 

Ground Source 

HP (+DHW) 19331 0 198.1 35% $ 1,933 35% $ 1,904 35% $ 575.1 $ 1,023 

BSP ++ 

 Solar DHW 17718 0 181.5 41% $ 1,772 41% $ 1,745 40% $ 158.9 $ 1,181 

BSP ++ 

 Lighting, Appl. & 

Plug 15690 0 160.8 48% $ 1,569 48% $ 1,545 47% $ 199.8 $ 1,381 

Site Generation 

BSP ++ 

 PV 8288 0 84.9 72% $ 829 $ 816 72% $ 729.0 $ 2,110 

 

5 Calculated using national average electric cost = $0.10/kWh and national average gas cost = $0.50/therm. 

33
References 

Abrams, D.W., and Shedd, A.C. 1996. “Effect of Seasonal Changes in Use Patterns and Cold Inlet Water 

Temperature on Water Heating Load.” ASHRAE Transactions, AT-96-18-3. 

American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). 2001. 

Fundamentals Handbook. Atlanta, GA: ASHRAE. 

American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). 1999. HVAC 

Applications Handbook. Atlanta, GA: ASHRAE. 

American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). 1993. A 

Method of Determining Air Change Rates in Detached Dwellings, ASHRAE Standard 136-1993, 

Atlanta, GA. 

American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). 1988. Air 

Leakage Performance for Detached Single-Family Residential Buildings, ASHRAE Standard 119-

1988, Atlanta, GA. 

American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). 2001. “Method 

of Test for Determining the Design and Seasonal Efficiencies of Residential Thermal Distribution 

Systems,” Proposed ASHRAE Standard 152P, Atlanta, GA. 

American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE). 1992. 

“Thermal Environmental Conditions for Human Occupancy,” ASHRAE Standard 55-1992, Atlanta, 

GA. 

Becker, B.R. and K.E. Stogsdill. 1990. “Development of Hot Water Use Data Base.” ASHRAE 

Transactions, Vol. 96, Part 2, pp. 422-427. American Society of Heating, Refrigerating and Air 

Conditioning Engineers, Atlanta, GA. 

Burch, J., and Salasovich, J. 2002. “Flow Rates and Draw Variability in Solar Domestic Hot Water 

Usage.” Proceedings of the Solar 2002 Conference Including Proceedings of the 31st ASES Annual 

Conference and Proceedings of the 27th National Passive Solar Conference, 15-20 June 2002, Reno, 

Nevada. Boulder, CO: American Solar Energy Society, Inc. (ASES); pp. 287-292; NREL Report No. 

CP-550-31779. 

Burch, J., and Erickson, P. 2004 (Draft). “Deriving Inputs for Storage Tank Water Heater Models from 

Rating Data.” Conference paper. Golden, CO: National Renewable Energy Laboratory. 

California Energy Commission. 2002. California Building Energy Efficiency Standards, Part 1, Measure 

Analysis and Life Cycle Cost, CEC, Sacramento, CA. 

Christensen, C., Barker, G., and Thornton, J. 2000. Parametric Study of Thermal Performance of 

Integral Collector Storage Solar Water Heaters. NREL Report No. CP-550-28043. Conference 

paper. Golden, CO: National Renewable Energy Laboratory. 

Eley Associates. 2002. Visual DOE Version 3.1. San Francisco, CA: Eley Associates. 

Environmental Protection Agency (EPA). 2006. Savings Calculator – Dehumidifier. Available online at 

http://www.energystar.gov/ia/business/bulk_purchasing/bpsavings_calc/CalculatorConsumerDehumi

difier.xls. Washington, DC: Environmental Protection Agency. 

34
Huang, J., and Gu, L. 2002 (Draft). Prototypical Residential Buildings to Represent the US Housing 

Stock. Berkeley, CA: Lawrence Berkeley National Laboratory. 

Hendron, R., Anderson, R., Judkoff, R., Christensen, C., Eastment, M., Norton, P., Reeves, P., Hancock, 

E. 2004. Building America Performance Analysis Procedures, Rev. 1. NREL/TP-550-35567, NREL, 

Golden, CO. 

International Code Council (ICC). 2003. International Energy Conservation Code 2003. Falls Church, 

VA: ICC. 

Kolb, G. October 2003. Private communication. Sandia National Laboratories, Albuquerque, NM. 

Manclark, B., and Nelson, M. 1992. The Grays Harbor PUD Compact Fluorescent Maximization Study.

Grays Harbor, WA: Grays Harbor Public Utility District. 

National Renewable Energy Laboratory (NREL). 1995. Solar Radiation Data Manual for Buildings. 

NREL/TP-463-7904. Golden, CO: NREL. 

Navigant Consulting. 2002. U.S. Lighting Market Characterization: Volume 1: National Lighting 

Inventory and Energy Consumption Estimate. Washington, DC: Navigant Consulting. 

Parker, D. 2002. Research Highlights from a Large Scale Residential Monitoring Study in a Hot Climate

(and personal communication). FSEC-PF369-02. Cocoa, FL: Florida Solar Energy Center. 

Parker, D., et al. September 2000. FPC Residential Monitoring Project: Assessment of Direct Load 

Control and Analysis of Winter Performance. Prepared for the Florida Power Corporation, FSEC-CR1112-99. Cocoa, FL. 

Pratt, R., Conner, C., Richman, E., Ritland, K., Sandusky, W., and Taylor, M. 1989. "Description of 

Electric Energy Use in Single-Family Residences in the Pacific Northwest – End-Use Load and 

Consumer Assessment Program (ELCAP)”, DOE/BP-13795-21, Pacific Northwest National 

Laboratory, Richland, WA. 

Residential Energy Services Network (RESNET). 2002. “Mortgage Industry National Home Energy 

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

Southern California Edison (SCE). 1993. Final Report: Residential Lighting Study (Inventory Results).

Rosemead, CA: SCE. 

U.S. Department of Energy (DOE). 1996. Residential Lighting Use and Potential Savings. DOE/EIA0555(96)/2. Washington, DC: U.S. DOE. 

U.S. Department of Energy (DOE). November 1999. “1997 Residential Energy Consumption Survey”. 

Available online at http://www.eia.doe.gov/emeu/recs/1997. Washington, DC: U.S. DOE. 

U.S. Department of Energy (DOE) (July 2002b), “2002 Buildings Energy Databook” online at 

http://btscoredatabook.eren.doe.gov/; see the 2003 databook at http://btscoredatabook.eren.doe.gov/

(accessed May 2004). Washington, DC: U.S. DOE. 

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Economy: A Beginning. Chapter 7. Available online at 

http://www.eia.doe.gov/emeu/efficiency/ee_report_html.htm (accessed May 2004). Washington, DC: 

U.S. DOE. 

35
U.S. Department of Energy (DOE). 2001a. Annual Energy Outlook 2002. Washington, DC: U.S. DOE. 

U.S. Department of Energy (DOE). May 2002a. “Residential Energy Efficiency and Appliance 

Standards.” http://www.eere.energy.gov/consumerinfo/refbriefs/ee8.html (accessed May 2004). 

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One- and Two-Family Living Units.” No. 4900.1-1982. Washington, DC: HUD. 

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Energy Calculations”. Masters Thesis, University of Colorado at Boulder.

36
REPORT DOCUMENTATION PAGE Form Approved 

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PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION.

1. REPORT DATE (DD-MM-YYYY)

January 2007 

2. REPORT TYPE

Technical report 

3. DATES COVERED (From - To)

 

5a. CONTRACT NUMBER

DE-AC36-99-GO10337 

5b. GRANT NUMBER

4. TITLE AND SUBTITLE

Building America Research Benchmark Definition, Updated 

December 15, 2006 

5c. PROGRAM ELEMENT NUMBER

5d. PROJECT NUMBER

NREL/TP-550-40968 

5e. TASK NUMBER

BET7.8004 

6. AUTHOR(S)

R. Hendron 

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/TP-550-40968 

10. SPONSOR/MONITOR'S ACRONYM(S)

NREL 

9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)

11. SPONSORING/MONITORING 

AGENCY REPORT NUMBER

12. DISTRIBUTION AVAILABILITY STATEMENT

National Technical Information Service 

U.S. Department of Commerce 

5285 Port Royal Road 

Springfield, VA 22161 

13. SUPPLEMENTARY NOTES

14. ABSTRACT (Maximum 200 Words)

To track progress toward aggressive multi-year whole-house energy savings goals of 40-70% and onsite power 

production of up to 30%, DOE’s Residential Buildings Program and NREL developed the Building America Research 

Benchmark in consultation with the Building America industry teams. 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 hot water. Unlike the reference homes 

used for HERS, EnergyStar, and most energy codes, the Benchmark represents typical construction at a fixed point 

in time so it can be used as the basis for Building America's multi-year energy savings goals without the complication 

of chasing a 'moving target'. 

15. SUBJECT TERMS

Building America; Building America Benchmark; Benchmark 

16. SECURITY CLASSIFICATION OF: 19a. NAME OF RESPONSIBLE PERSON 

a. REPORT 

Unclassified 

b. ABSTRACT 

Unclassified

c. THIS PAGE 

Unclassified

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OF ABSTRACT

UL 

18. NUMBER 

OF PAGES 

19b. TELEPONE 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

Visit our Web sites at:

www.buildingamerica.gov www.pathnet.org www.energystar.gov

Research Toward Zero Energy Homes

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 • IBACOS provided technical support for TNAH ‘07

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 • IHP provided on-site support for TNAH ‘07

National Council of the Housing Industry (NCHI) of the NAHB

Tucker Bernard • NCHI • The Supplier 100 • National Association of Home Builders (NAHB) • 1201 15th St. NW, Washington, D.C. 

20005 • 800-368-5242 ext. 8519 • e-mail: tbernard@nahb.org • www.nahb.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

Pacific Northwest National Laboratory

Michael C. Baechler • 620 Southwest 5th, Suite 810 • Portland, OR 97204 • 503-417-7553 • fax: 503-417-2175 • 

e-mail: michael.baechler@pnl.gov • www.pnl.gov

Produced for the U.S. Department of Energy (DOE) by the National Renewable Energy Laboratory, a DOE national laboratory.

January 2007 • NREL/TP-550-40968

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