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Building Technologies Program

T OF ENERGY

DEPARTMEN

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NITED STAT S OFA ERICA

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Research Toward Zero Energy Homes May 2006 • NREL/TP-550-38238

Building America Performance Analysis 

Procedures for Existing Homes

Robert Hendron

National Renewable Energy Laboratory

Sara Farrar/PIX07134
Building America Performance 

Analysis Procedures for Existing 

Homes 

R. Hendron 

Prepared under Task No. BET6.8004 

Technical Report 

NREL/TP-550-38238 

May 2006 

National Renewable Energy Laboratory 

1617 Cole Boulevard, Golden, Colorado 80401-3393 

303-275-3000 • www.nrel.gov 

Operated for the U.S. Department of Energy 

Office of Energy Efficiency and Renewable Energy 

by Midwest Research Institute • Battelle 

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

Background ..................................................................................................................... 1 

Purpose of the Report ..................................................................................................... 1 

Analysis Tools ................................................................................................................. 2 

Modeling of the Pre-Retrofit Case ................................................................................... 3 

General ...................................................................................................................... 3 

Building Envelope ...................................................................................................... 3 

Space-Conditioning / Air-Distribution Equipment ....................................................... 6 

Domestic Hot Water................................................................................................. 13 

Air Infiltration and Ventilation ................................................................................... 19 

Lighting Equipment and Usage................................................................................ 19 

Appliances and Miscellaneous Electric Loads ......................................................... 21 

Site Generation........................................................................................................ 30 

Modeling the Post-Retrofit Case ................................................................................... 30 

Operating Conditions..................................................................................................... 32 

Reporting Energy Use and Energy Savings.................................................................. 35 

References.................................................................................................................... 40 

iii
 List of Figures 

Figure 1. Clothes washer hot water use profile ........................................................... 16 

Figure 2. Dishwasher hot water use profile ................................................................. 17 

Figure 3. Shower, bath, and sink hot water use profile................................................ 17 

Figure 4. Combined domestic hot water use profile .................................................... 18 

Figure 5. Annual average interior lighting profile (built up from detailed profiles)........ 21 

Figure 6. Example of a detailed lighting profile (expressed as fraction of 

 peak daily lighting energy)........................................................................... 21 

Figure 7. Total combined residential equipment profile .............................................. 26 

Figure 8. Refrigerator and freezer normalized energy use profile............................... 27 

Figure 9. Clothes washer normalized machine energy use profile ............................. 27 

Figure 10. Clothes dryer normalized energy use profile ............................................... 28 

Figure 11. Dishwasher normalized energy use profile.................................................. 28 

Figure 12. Range / oven normalized energy use profile................................................ 29 

Figure 13. Miscellaneous electric load normalized energy use profile.......................... 29 

Figure 14. Average hourly load profile from occupants for all day-types 

 and family types (16.5 hours/day/person total)............................................ 34 

Figure 15. Detailed hourly load profiles resulting from occupants being in 

 different parts of the house on weekdays (WD) and weekends (WE).......... 34 

iv
List of Tables 

Table 1. Default R-Values for Wall Cavity Insulation .................................................... 4 

Table 2. Default R-Values for Floors above Unconditioned Space............................... 4 

Table 3. Default R-Values for Common Insulation Types ............................................ 4 

Table 4. Default Solar Adsorptances for Common Roofing Surfaces........................... 5 

Table 5. Default Wood-framing Factors........................................................................ 6 

Table 6. Default Furnace and Boiler System Efficiencies, “Gas” refers to 

either Natural Gas or Propane........................................................................ 8 

Table 7. Default Heating-System Blower and Auxiliary Electricity Consumption .......... 9 

Table 8. Default Air Conditioning and Heat-Pump Efficiencies................................... 10 

Table 9. Default DHW Energy Factors, Known Equipment Characteristics. 

 “Gas” Refers to Either Natural Gas or Propane........................................... 14 

Table 10. Default Domestic Hot Water Consumption by End Use................................ 15 

Table 11. Default Dishwasher Characteristics.............................................................. 15 

Table 12. Default Standard Size (~2.5 ft3

) Clothes Washer Characteristics................. 16 

Table 13. Default Lighting Operating Hours for Common Room Types........................ 20 

Table 14. Default Gas Clothes Dryer Characteristics (Assumes Typical 1990 

Clothes Washer Capacity and Remaining Moisture Content)....................... 22 

Table 15. Default Electric Clothes Dryer Characteristics (Assumes Typical 

1990 Clothes Washer Capacity and Remaining Moisture Content).............. 23 

Table 16. Default Gas Over / Cooktop Characteristics................................................. 23 

Table 17. Default Electric Oven / Cooktop Characteristics........................................... 24 

Table 18. Default Internal Loads from Appliances and Small Electric 

End-Uses in the Pre-Retrofit Case ............................................................... 25 

Table 19. Peak Sensible and Latent Heat Gain from Occupants ................................. 33 

v
Table 20. Example Summary of Site Energy Consumption by End-Use for 

an Existing Homes Project............................................................................ 36 

Table 21. Example Summary of Source Energy Consumption by End-Use 

for an Existing Homes Project ...................................................................... 37 

Table 22. End-Use Categories ..................................................................................... 38 

Table 23. Example Measure Savings Report for an Existing Homes Project ............... 39 

vi
Definitions 

ACH air changes per hour 

AFUE Annual Fuel Utilization Efficiency 

ASHRAE American Society of Heating, Refrigerating and AirConditioning Engineers 

ASTM American Society for Testing and Materials 

BA Building America 

BESTEST A benchmark for building energy simulation: Building Energy 

Simulation Test and Diagnostic Method 

CAAFUE combined appliance AFUE 

CFA conditioned floor area 

DOE U.S. Department of Energy 

DOE-2 building energy analysis program that can predict the 

energy use and cost for all types of buildings 

DHW domestic hot water 

DSE distribution system efficiency 

DUF dryer usage factor 

ECM electronically commutated motor 

EER energy efficiency ratino 

EF efficiency factor 

EIA Energy Information Administration 

ELCAP End-Use Load and Consumer Assessment Program 

EPA U.S. Environmental Protection Agency 

EPRI Electric Power Research Institute 

EPS expanded polystyrene 

FFA finished floor area 

H height of one story 

HERS Home Energy Rating System developed by RESNET 

HSPF heating seasonal performance factor 

LBNL Lawrence Berkeley National Laboratory 

M maintenance factor 

MAT monthly average temperatures 

vii
MEF modified energy factor 

MEL miscellaneous electric loads 

NAECA National Appliance Energy Conservation Act 

NREL National Renewable Energy Laboratory 

OA outdoor air 

RECS EIA Residential Energy Consumption Survey 

RESNET Residential Energy Service Network 

SDT summer design temperatures 

SEER seasonal energy efficiency ratio 

SHGC solar heat gain coefficient 

TMY2 Typical Meteorological Year weather data (1961-90) 

TREAT Building energy software that performs hourly simulations 

for single-family, multi-family, and mobile homes 

TRNSYS The Transient Energy System Simulation Tool is software 

designed to simulate the transient performance of thermal 

energy systems 

TXV thermostatic expansion valve 

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

thermal conductance of the structure along with heat 

transfer resulting from convection and radiation 

UA heat loss coefficient 

WDT winter design temperatures 

XPS extruded polystyrene 

viii
Building America Performance Analysis Procedures for Existing 

Homes 

Background 

Because there are more than 101 million residential households in the United States today, it is 

not surprising that existing residential buildings represent an extremely large source of potential 

energy savings. Because thousands of these homes are renovated each year, the U.S. Department 

of Energy’s (DOE’s) Building America program is investigating the best ways to make existing 

homes more energy-efficient, based on lessons learned from research in new homes. The 

Building America research goals target a 20% reduction in energy use in existing homes by 2015 

and a 30% reduction by 2025. 

The strategy for the existing homes project of Building America is to establish technology 

pathways that reduce energy consumption cost-effectively in American homes. The existing 

buildings project focuses on finding ways to adapt the results from the new homes research to 

retrofit applications in existing homes. Research activities include a combination of computer 

modeling, field demonstrations, and long-term monitoring to support the development of 

integrated approaches to reduce energy use in existing residential buildings. Analytical tools are 

being developed to guide designers and builders in selecting the best approaches for each 

application. Also, DOE partners with the U.S. Environmental Protection Agency (EPA) to 

increase energy efficiency in existing homes through the Home Performance with ENERGY 

STAR® program 

(www.energystar.gov/index.cfm?c=home_improvement.hm_improvement_hpwes). 

Purpose of the Report 

This report provides a proposed set of guidelines for estimating the energy savings achieved by a 

package of retrofits or an extensive rehabilitation of an existing home. Building America has 

developed a set of typical operating conditions that will be used for the purpose of using a 

building simulation model to objectively compare energy use before and after a series of retrofits 

are completed. Actual occupant behavior is extremely important for the purpose of determining 

the cost-effectiveness of a retrofit package, especially if the homeowner is paying the bills. But 

for the purpose of tracking progress toward programmatic goals, and for comparing the 

performance of one house to another, it is essential to use a hypothetical set of occupants with 

typical behavioral patterns. These typical operating conditions are fully consistent with those 

used in the Building America Research Benchmark for new construction (which we will refer to 

simply as the Benchmark) (Hendron 2005). 

Certain field test and audit methods are also described in this report. These tests help establish 

accurate building system performance characteristics that are needed for a meaningful simulation 

of whole-house energy use. Several sets of default efficiency values have also been developed 

for certain older appliances that cannot be easily tested and for which published specifications 

are not readily available. 

1
Analysis Tools 

A key issue in any building energy analysis is which tool or program should be chosen to 

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

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

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

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

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

and level of technical support, DOE-2 is the hourly simulation tool recommended for systems 

analysis studies performed under the DOE Building America program. 

EnergyGauge1

 is a frequently used interface for DOE-2 because it has been tailored specifically 

to residential buildings. However, it was not designed with existing homes as the top priority, so 

retrofits must be analyzed by comparing separate runs. Team analysts are encouraged to use 

other simulation tools when appropriate for specialized building simulation analysis, provided 

the tool has met the requirements of BESTEST in accordance with the software certification 

sections of the RESNET/HERS Guidelines (RESNET 2002). Regardless of the tool selected, 

teams should present complete analysis results, in accordance with the reporting guidelines 

described later in this section. 

Most of the simulation tools that are useful for new residential construction are also applicable to 

residential retrofit analysis. Certain tools, such as TREAT, offer additional features such as sideby-side comparisons, automated efficiency package recommendations, and utility bill 

analysis/reconciliation. Further information about TREAT and a number of other useful tools for 

retrofit analysis of both residential and commercial buildings can be found in the DOE Energy 

Software Tools Directory (www.eere.energy.gov/buildings/tools_directory). 

NREL does not recommend that utility bills be heavily relied upon as a tool for model validation, 

except as an approximate check of model accuracy. There are two important reasons for this 

position: 

• It is extremely difficult to accurately determine occupant behavior during the time period 

reflected in the utility bills. 

• The large number of uncertain input parameters allows multiple ways to reconcile the model 

with the small number of utility bills, and no reliable methodology exists for performing this 

calibration because the problem is fundamentally mathematically underdetermined. 

Instead, detailed inspections, short-term testing, and long-term monitoring should be utilized to 

the greatest extent possible to minimize the uncertainty in model inputs. Default values may be 

used when certain building features are inaccessible (wall insulation) or efficiency characteristics 

cannot be readily determined through inspection or short-term testing (furnace AFUE). The 

effects of maintenance and repairs should always be considered when using default values for 

equipment efficiency or the amount of insulation. 

Throughout the remainder of this section, the term “Pre-Retrofit Case” refers to the state of an 

existing house immediately before it undergoes a series of upgrades, repairs, additions, or 

 

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

2
renovations. These measures may be limited to a focused set of energy efficiency improvements 

to the house or may be part of a larger remodeling or gut rehabilitation effort. The terms “PostRetrofit Case” and “Prototype” refer to the same existing house after the package of 

improvements is complete. 

Modeling the Pre-Retrofit Case 

General 

Any element of the Pre-Retrofit Case that is not specifically addressed in the following sections, 

or is not changed as part of the package of energy efficiency measures, is assumed to be the same 

as the Post-Retrofit Case. 

Building Envelope 

To the extent possible, all building envelope components (including walls, windows, foundation, 

roof, and floors) for the Pre-Retrofit Case shall be based on physical inspections, audits, design 

specifications, or measured data. Co-heating (Judkoff et al. 2000), or infrared imaging during 

cold weather can provide useful information about the insulation quality of the house without 

damaging the building envelope. A Short-Term Monitoring Tests (STEM) can provide the 

overall building loss coefficient and thermal mass (Judkoff et al. 2000), but in most retrofit 

scenarios a STEM test is overly expensive and would not provide data that could be easily 

factored into a building simulation. 

If detailed envelope characteristics cannot be obtained, the following default specifications may 

be used: 

• R-values for cavity insulation in exterior 2x4 or 2x6 wood frame walls from Table 1 

• R-values for cavity insulation in floors over unconditioned space from Table 2 

• Insulation thickness in all other locations shall be measured, and the default R-values per 

inch in Table 3 shall be applied 

• Default U-values for vertical fenestration, including windows and sliding glass doors, from 

Table 4 in Chapter 31 of the 2005 ASHRAE Handbook of Fundamentals (ASHRAE 2005) 

• Total assembly SHGC for vertical fenestration from Table 13 in Chapter 31 of the 

2005 ASHRAE Handbook of Fundamentals 

• Default solar absorptivity equal to 0.50 for opaque areas of exterior walls and from Table 4 

for opaque areas of roofs 

• Default total infrared emittance of exterior walls and roofs equal to 0.90 

• The default framing factors in Table 5 may be used for houses using wood construction. 

3
Table 1. Default R-values for Wall Cavity Insulation (Based in Part on Huang & Gu 2002) 

Year of Construction Wall Construction 

Type 1990+ 1980-89 1950-79 Pre 1950 

2x4, 16 in. o.c. 13 11 9 7 

2x6, 24 in. o.c. 19 17 15 13 

Table 2. Default R-Values for Floors above Unconditioned Space 

(Based in Part on Huang & Gu 2002) 

Year of Construction Building America 

Climate Region 1990+ 1980-89 1950-79 Pre 1950 

Cold, Very Cold, 

Subarctic, Marine 19 17 15 13 

All Others 0 0 0 0 

Table 3. Default R-value for Common Insulation Types (DOE 2003, E-Star Colorado 2005) 

Year of Construction 

Insulation Material 

1990 or after Before 1990 

High-Density Fiberglass Batt 3.8 / in. 3.0 / in. 

Low-Density Fiberglass Batt 2.7 / in. 2.0 / in. 

Loose-Fill Fiberglass 3.2 / in. 2.5 / in. 

Cellulose (Blown, Wet, or Dry) 3.7 / in. 3.4 / in. 

Expanded Polystyrene (EPS) 4.0 / in. 3.8 / in. 

Extruded Polystyrene (XPS) 5.0 / in. 4.8 / in. 

Open-Cell Polyurethane Foam 3.6 / in. 3.3 / in. 

Closed-Cell Polyurethane Foam 6.5 / in. 5.9 / in. 

Rigid Polyisocyanurate 7.2 / in. 5.8 / in. 

4
Table 4. Default Solar Absorptances for Common Roofing Surfaces (Parker et al. 2000) 

Roof Material Absorptance Roof Material Absorptance

Composition Shingles Wood Shingles 

 Dark 0.92 Dark 0.90 

 Medium 0.85 Medium 0.80 

 Light 0.75 

Concrete/Cement 

Tile/Slate Dark 0.90 

 Dark 0.90 Medium 0.75 

 Medium 0.75 Light 0.60 

 Terra cotta 0.65 White 0.30 

 Light 0.60 

 White 0.30 Membrane 

 Dark 0.90 

Metal Medium 0.75 

 Dark 0.90 Light 0.60 

 Medium 0.75 White 0.30 

 Galvanized, unfinished 0.70 

 Light 0.60 Built-up (gravel surface) 

 Galvalum, unfinished 0.35 Dark 0.92 

 White 0.30 Medium 0.85 

 Light 0.75 

5
Table 5. Default Wood-framing Factors 

Frame Spacing 

Framing 

Fraction Enclosure 

Element 

(in. o.c.) (% area) 

Walls 16 23% 

Floors 16 13% 

Ceilings 24 11% 

Space Conditioning / Air-Distribution Equipment 

To the extent possible, the performance characteristics (efficiency and capacity) of all spaceconditioning components (including heating system, cooling system, dehumidification, air 

handler, and ducts) for the Pre-Retrofit Case shall be based on physical inspections, audits, 

design specifications, and measured data. An estimate of Annual Fuel Utilization Efficiency 

(AFUE) for a furnace or Heating Seasonal Performance Factor (HSPF) for a heat pump can be 

estimated by performing a co-heating test to determine the building loss coefficient (Judkoff et 

al. 2000), then measuring the gas or electricity input over a period of time with known inside and 

outside temperatures. Because thermal mass and solar effects complicate this approach, it should 

ideally be conducted under near steady-state conditions at night. Field-audit procedures for 

heating equipment have also been developed by LBNL (Szydlowski and Cleary 1988). Cooling 

efficiency is much more difficult to measure directly; in most cases, the manufacturers published 

data must be used—or default values if published performance data are not available. 

Default furnace or boiler system efficiency may be calculated using Equation 1 in conjunction 

with the parameters in Table 6 if the actual efficiency of the equipment is unknown and cannot 

be readily obtained through field-testing (for example, if the audit is conducted in the summer, 

the heating system is broken, or testing would be cost-prohibitive). Typical base values for 

AFUE were obtained from the ASHRAE HVAC Systems and Equipment Handbook (ASHRAE 

2004a), the 1987 EPRI Technical Assessment Guide (EPRI 1987), and the Technical Support 

Documents for the NAECA appliance standards (DOE 2004a). Default AFUE values for system 

configurations not listed in Table 6 may be estimated using these references. Estimates of 

degradation rates are partly based on the E-Source Space Heating Technology Atlas (E-Source 

1993). 

Equation 1: AFUE = (Base AFUE) * (1-M)age 

 Where: 

Base AFUE = Typical efficiency of Pre-Retrofit equipment when new 

M = Maintenance Factor 

Age = Age of equipment in years. 

6
For example, the default AFUE for a 10-year-old, poorly maintained, oil furnace with a 

conventional burner would be calculated as follows: 

 AFUE = (71) * (1-0.025)10 = 55%. 

Auxiliary electricity use for furnaces and boilers, including blowers and controls, shall be 

measured directly if possible. If accurate measurements cannot be made, the default values of 

auxiliary electricity use in Table 7 may be used. 

The default air-conditioner and heat-pump efficiencies in Table 8 may be used if the actual 

efficiency cannot be calculated or measured. Base values for SEER, EER, and HSPF were 

obtained from the engineering analysis of appliance standards for air conditioners and heat 

pumps (DOE 2002), and from the LBNL Energy Data Sourcebook (Wenzel et al. 1997). Default 

efficiencies for equipment not listed in the table may either be interpolated or estimated by 

referring to the original references. Adjustments to efficiency related to age and quality of 

maintenance shall be applied in accordance with Equation 2. Performance degradation rates for 

cooling systems are based in part on a study done by LBNL for the California Energy 

Commission (Matson et al. 2002). 

Equation 2: EFF = (Base EFF) * (1-M)age 

 Where: 

Base EFF = Typical efficiency of Pre-Retrofit equipment when new (SEER, 

EER, or HSPF) 

M = Maintenance Factor 

Age = Age of equipment in years. 

7
Table 6. Default Furnace and Boiler System Efficiencies; 

“Gas” Refers to Either Natural Gas or Propane 

Maintenance Factor (M) 

Type of Space-Heating Equipment 

Base 

AFUE* Annual 

Professional 

Maintenance 

Seldom or 

Never 

Maintained 

Condensing gas furnace 90 0.005 0.015 

Gas furnace, direct-vent or forceddraft combustion, electronic ignition, 

in conditioned space 

80 0.005 0.015 

Gas furnace, natural-draft 

combustion, vent damper, electronic 

ignition, in conditioned space 

78 0.005 0.015 

Gas furnace, natural-draft 

combustion, standing pilot light, in 

conditioned space 

75 0.005 0.015 

Gas furnace, natural-draft 

combustion, standing pilot light, no 

vent damper, in unconditioned space 

64 0.005 0.015 

Gas hot water boiler, natural-draft 

combustion, standing pilot light 80 0.005 0.015 

Gas steam boiler 81 0.005 0.015 

Condensing gas boiler 90 0.005 0.015 

Gas hot water / fan-coil combo 

system 80 0.005 0.015 

Gas boiler / tankless coil combo 

system 80 0.005 0.015 

Gas space heater, fan type 73 0.005 0.015 

Gas space heater, gravity type 60 0.005 0.015 

Oil furnace, flame-retention burner, 

vent dampers, in conditioned space 81 0.01 0.025 

8
Table 6 continued. Default Furnace and Boiler System Efficiencies; 

“Gas” Refers to Either Natural Gas or Propane 

Maintenance Factor (M) 

Type of Space-Heating Equipment 

Base 

AFUE* Annual 

Professional 

Maintenance 

Seldom or 

Never 

Maintained 

Oil furnace, conventional burner, no 

vent dampers, in conditioned space 71 0.01 0.025 

Oil hot water boiler, forced-draft 

combustion 80 0.01 0.025 

Oil steam boiler 82 0.01 0.025 

Electric-resistance furnace or boiler, 

conditioned space 100 0 0 

Electric-resistance furnace or boiler, 

unconditioned space 98 0.001 0.001 

Electric-resistance baseboard 

heating 100 0 0 

Electric space heater 100 0 0 

* Combined Appliance AFUE (CAAFUE) for combo systems 

Table 7. Default Heating-System Blower and Auxiliary Electricity Consumption 

Type of Heating Equipment Electricity/Capacity 

Gas furnace (including mobile-home furnace) 9.2 (kWh/yr)/(kBtu/hr) 

Gas hot water boiler with hydronic distribution 1.1 (kWh/yr)/(kBtu/hr) 

Gas boiler with forced-air distribution 9.2 (kWh/yr)/(kBtu/hr) 

Oil furnace 8.0 (kWh/yr)/(kBtu/hr) 

Oil hot water boiler with hydronic distribution 2.3 (kWh/yr)/(kBtu/hr) 

Electric furnace Included in AFUE 

9
Table 8. Default Air-Conditioning and Heat-Pump Efficiencies 

Maintenance Factor (M) 

Type of Air-Conditioning or 

Heat-Pump Equipment 

Base 

SEER

Base 

EER

Base 

HSPF Annual 

Professional 

Maintenance 

Seldom or 

Never 

Maintained 

Split central air conditioner, twospeed reciprocating compressor, 

electronically commutated air 

handler motor (ECM), 

thermostatic expansion valve 

(TXV), fan coil 

14 10.5 0.01 0.02 

Split central air conditioner, 

single-speed scroll compressor, 

ECM air handler motor, cased 

coil 

12 10.8 0.01 0.03 

Split central air conditioner, 

single-speed reciprocating 

compressor, PSC air-handler 

motor, cased coil (after 1991) 

10 9.3 0.01 0.03 

Split central air conditioner, 

single-speed reciprocating 

compressor, PSC air-handler 

motor, cased coil (1981-1991) 

8 7.7 0.01 0.03 

Split central air conditioner, 

single-speed reciprocating 

compressor, PSC air-handler 

motor, cased coil (before 1981) 

6.5 6.4 0.01 0.03 

Split heat pump, single-speed 

scroll compressor, ECM air 

handler motor, TXV valve 

14 10.5 8.0 0.01 0.03 

10
Table 8 continued. Default Air Conditioning and Heat-Pump Efficiencies 

Maintenance Factor (M) 

Type of Air-Conditioning or 

Heat-Pump Equipment 

Base 

SEER

Base 

EER

Base 

HSPF Annual 

Professional 

Maintenance 

Seldom or 

Never 

Maintained 

Split heat pump, single-speed 

reciprocating compressor, PSC 

air-handler motor (after 1991) 

10 9.3 7.1 0.01 0.03 

Split heat pump, single-speed 

reciprocating compressor, PSC 

air-handler motor (1981-1991) 

8 7.7 6.6 0.01 0.03 

Split heat pump, single-speed 

reciprocating compressor, PSC 

air-handler motor (before 1981) 

6.5 6.4 6.0 0.01 0.03 

Packaged central air conditioner, 

single-speed reciprocating 

compressor, PSC air-handler 

motor 

10 9.1 0.01 0.03 

Packaged heat pump, singlespeed reciprocating compressor, 

PSC air-handler motor 

10 9.1 6.8 0.01 0.03 

Room air conditioner, louvered 

sides, cooling only, single-speed 

compressor, PSC fan motor, 

<20,000 Btu/hr (after 1991) 

9.75 0.01 0.03 

Room air conditioner, louvered 

sides, cooling only, single-speed 

compressor, PSC fan motor, 

≥20,000 Btu/hr (after 1991) 

8.5 0.01 0.03 

11
Table 8 continued. Default Air Conditioning and Heat-pump Efficiencies 

Maintenance Factor (M) 

Type of Air-Conditioning or 

Heat-Pump Equipment 

Base 

SEER

Base 

EER

Base 

HSPF Annual 

Professional 

Maintenance 

Seldom or 

Never 

Maintained 

Room air conditioner, louvered 

sides, cooling only, single-speed 

compressor, PSC fan motor, 

(1981-1991) 

7.5 0.01 0.03 

Room air conditioner, louvered 

sides, cooling only, single-speed 

compressor, PSC fan motor, 

(before 1981) 

6.5 0.01 0.03 

Room electric heat pump, 

louvered sides, single-speed 

compressor, PSC fan motor, 

<20,000 Btu/hr 

9 0.01 0.03 

Room electric heat pump, 

louvered sides, single-speed 

compressor, PSC fan motor, 

≥20,000 Btu/hr 

8.5 0.01 0.03 

Direct evaporative cooling 25 0.02 0.05 

12
For houses with air ducts, the Pre-Retrofit Case shall be modeled using data collected through 

visual inspections, physical measurements, and duct-leakage testing. Default values for duct 

leakage shall not be used. Duct-blaster testing shall be conducted in accordance with ASTM 

E1554 (ASTM 1994). Tracer gas testing of the air distribution system is encouraged when 

possible, and shall be conducted in accordance with NREL Performance Test Practices for duct 

systems (Hancock et al. 2002). 

If the simulation tool does not permit the input of detailed duct specifications, 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 expected energy 

losses from ducts. The DSE values shall be estimated using the procedures in the Draft 

ASHRAE Standard 152P (ASHRAE 2001). 

For houses with hydronic space-heating or space-cooling systems, a distribution efficiency of 

95% shall be applied to the appliance efficiency, representing a small amount of energy loss 

through the pipes. 

Domestic Hot Water 

To the extent possible, the specifications of the domestic hot water system in the Pre-Retrofit 

Case shall be based on audits, design specifications, physical measurements, and test data. 

Published data from the manufacturer provides the most reliable estimate of energy factor, 

because in-situ testing introduces several uncontrolled variables (such as water use and ambient 

temperature) that usually make a reliable measurement of standby loss impossible. The 

procedures to measure recovery efficiency and standby losses described by LBNL (Szydlowski 

and Cleary 1988) may be used in conjunction with the NREL tank loss spreadsheet 

(www.eere.energy.gov/buildings/building_america/docs/tankloss.xls) to give a rough estimate of 

the energy factor (EF). If EF of the equipment cannot be determined through measurement or 

examination of the published performance data, the default specifications in Table 9 may be 

used, with age and maintenance adjustments in accordance with Equation 3. These defaults were 

largely derived from technical support documents for the federal appliance standard for water 

heaters (DOE 2000a). 

Equation 3: EF = (Base EF) * (1-M)age 

 Where: 

Base EF = Typical efficiency of Pre-Retrofit equipment when purchased 

M = Maintenance Factor 

Age = Age of equipment in years. 

13
Table 9. Default DHW Energy Factors, Known Equipment Characteristics; 

“Gas” Refers to Either Natural Gas or Propane 

Maintenance Factor (M) 

Type of Water-Heating Equipment 

Base 

Energy 

Factor 

(EF)

Annual 

Professional 

Maintenance 

Seldom or 

Never 

Maintained 

Gas water heater, 40-gallon tank, pilot 

light, natural-draft combustion, poorly 

insulated, no heat traps, poor heat 

recovery from flue 

0.45 0.005 0.01 

Gas water heater, 40-gallon tank, pilot 

light, natural-draft combustion, 1-in. 

insulation, no heat traps, standard flue 

baffling 

0.54 0.005 0.01 

Gas water heater, 40-gallon tank, 

intermittent ignition, forced draft 

combustion, 3-in. insulation, heat traps, 

enhanced flue baffling, flue/vent 

dampers 

0.64 0.005 0.01 

Gas instantaneous water heater 0.80 0.005 0.01 

Oil water heater, 32-gallon tank, 

intermittent ignition, forced-draft 

combustion, poorly insulated, no heat 

traps, poor heat recovery from flue 

0.53 0.005 0.01 

Oil water heater, 32-gallon tank, 

interrupted ignition, forced-draft 

combustion, 3-in. insulation, heat traps, 

enhanced flue baffling 

0.61 0.005 0.01 

Electric water heater, 50-gallon tank, 

poorly insulated, no heat traps 0.79 0.001 0.002 

Electric water heater, 50-gallon tank, 

1.5-in. insulation, heat traps. 0.87 0.001 0.002 

Electric water heater, 50-gallon tank, 3-

in. insulation, heat traps. 0.90 0.001 0.002 

Electric instantaneous water heater 1.00 0 0 

14
The NREL Performance Analysis Spreadsheet calculates the correct DHW inputs for the 

TRNSYS computer program, including standby heat loss coefficient (UA), given basic 

equipment characteristics (EF, RE, etc) (Burch and Erickson 2004). It can be found on the 

Building America Web site in the section for building scientists 

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

Four major end uses have been identified for domestic hot water: showers, sinks, dishwasher, 

and clothes washer (Table 10). For showers and sinks, the specified volume is the same as the 

value defined for the Benchmark and represents the combined volume of hot and cold water. 

For clothes washers and dishwashers, the Appliance and DHW Spreadsheet developed by NREL 

shall be used to estimate the Pre- and Post-Retrofit hot water consumption based on standard 

operating conditions and information listed on the EnergyGuide label. If no EnergyGuide label 

is available, then the default values of energy factor for dishwashers (Table 11) or modified 

energy factor (MEF) for clothes washers (Table 12) shall be used for the Pre-Retrofit Case. 

Table 10. Default Domestic Hot Water Consumption by End-use 

End Use End-Use Water 

Temperature Default Water Usage 

Dishwasher N/A Calculated using EF in Table 10 

Clothes Washer N/A Calculated using MEF in Table 11 

Shower and Bath 105°F 17.5 + 5.83 x Nbr gal/day (Hot + Cold) 

Sinks 105°F 12.5 + 4.16 x Nbr gal/day (Hot + Cold) 

Table 11. Default Dishwasher Characteristics 

Equipment Characteristics Energy Factor 

(load/kWh) 

Power dry optional, multi-tier spray device, load-size and soillevel controls 0.6 

Power dry optional, multi-tier spray device, no load-size or soillevel controls 0.43 

Power dry always, single-tier spray device, no load-size or soillevel controls 0.24 

15
Table 12. Default Standard Size (~2.5 ft3

) Clothes Washer Characteristics 

Equipment Characteristics Modified Energy 

Factor (ft3/kWh) 

Horizontal axis, cold rinse option, automatic fill, thermostatically 

controlled mixing valve, improved water extraction 1.62 

Vertical axis, cold rinse option, automatic fill, thermostatically 

controlled mixing valve, improved water extraction 1.02 

Vertical axis, cold rinse option, water level option, standard 

mixing valve 0.64 

Vertical axis, no cold rinse option, no water level option 0.47 

The hourly hot water use profiles for individual end-uses in existing homes (Figures 1 through 3) 

are the same as the profiles recommended by Building America for analyzing new construction 

(Hendron 2005). For software tools that do not accept this level of detail, or if no DHW end-use 

improvements have been made to the house, then the combined hourly hot water profile may be 

used (Figure 4). 

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 1. Clothes washer hot water use profile 

16
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 2. Dishwasher 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 3. Shower, bath, and sink hot water use profile 

17
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 4. Combined domestic hot water use profile 

The mains water temperature, which is an important driver of water-heating energy, varies 

significantly depending on the location and time of year. Equation 4, based on TMY2 data for 

the geographic location of the existing house, shall be used to estimate the daily mains water 

temperature for both the Pre- and Post-Retrofit Cases. Because temperature changes between the 

mains and the DHW inlet and/or cold water fixtures are not factored into this equation, it is 

currently assumed that the mains temperature and the cold water temperature inside the house are 

approximately the same. The derivation of the mains temperature equation is discussed in more 

detail in the Benchmark report (Hendron 2005). 

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

15 - lag) - 90) 

 where: 

Tmains = mains temperature (°F), assumed equal to the cold water 

 supply temperature 

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

∆Tamb,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). 

18
Air Infiltration and Ventilation 

The effective leakage area for the Pre-Retrofit Case shall be calculated based on blower door 

testing conducted in accordance with ASTM E779-03 (ASTM 2003). If the whole-house 

simulation tool being used 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. 

Additional air exchange resulting from mechanical ventilation shall be assumed for the model of 

the Pre-Retrofit Case, if it does not meet the ventilation guidelines of ASHRAE Standard 62.2-

2004 (ASHRAE 2004b) for existing homes based on natural infiltration plus any existing 

mechanical ventilation system. This “supplemental” mechanical ventilation shall be calculated 

using Equation 5, which is based on a simple continuous exhaust fan designed to raise the total 

ventilation rate to the minimum values specified in Equation 4.1a of ASHRAE Standard 62.2-

2004, taking into account any infiltration credit allowed under Section 4.1.3. Supplemental 

mechanical ventilation shall be combined with the actual ventilation and natural infiltration in 

accordance with Section 4.4 of ASHRAE Standard 136 to determine an approximate combined 

effective air-change rate. The fan energy use associated with supplemental mechanical 

ventilation for the Pre-Retrofit shall be calculated using Equation 6 and added to the energy used 

by any actual ventilation fan present in the house. 

Equation 5: Qsup = [0.01 x FFA + 7.5 x (Nbr +1)] – [AI x CFA x H / 60 – 2 x FFA / 100] / 2 

 where: 

Qsup = supplemental mechanical ventilation assumed for the Pre-Retrofit Case 

 (cfm) not including interactions with natural infiltration 

FFA = finished floor area (ft2

) 

CFA = conditioned floor area, including directly or indirectly conditioned 

 basements (ft2) 

H = average height of one story (ft) 

AI = annual average air changes per hour resulting from natural infiltration 

 (ACH) 

Nbr = number of bedrooms. 

Equation 6: Supplemental ventilation fan energy (kWh/yr) = 3.942 x Qsup.

Lighting Equipment and Usage 

The total annual lighting budget for the Pre-Retrofit case shall be determined by conducting a 

detailed audit of light fixtures and bulbs inside and outside the house. Operating hours may be 

determined through long-term monitoring or by conducting occupant interviews or surveys. If 

19
reliable estimates of operating hours cannot be obtained or calculated, then the default operating 

hours estimated in the Navigant study may be used (Table 13). 

Table 13. Default Lighting Operating Hours for Common Room Types (Navigant 2002) 

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 

The annual average normalized daily load shape for interior lighting use is shown in Figure 5 and 

is the same profile used by Building America in the context of new construction. This load 

shape is also used for exterior and garage lighting. Monthly variations in load shape and lighting 

energy use resulting from 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. 

Other factors may also be considered, including 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 6. Other profiles are included in spreadsheets 

available on the Building America Web site 

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

20
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 5. Annual average interior lighting profile (built up from detailed profiles) 

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 6. Example of a detailed lighting profile (expressed as fraction of 

peak daily lighting energy) 

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 heat gain, and the fraction of the load that 

becomes a latent heat gain. 

21
To the extent possible, actual specifications for all major appliances should be obtained through 

inspection. Spot electricity measurements may be performed for loads that are relatively 

constant when operating, such as refrigerators and freezers. A more standardized procedure for 

calculating average daily electricity use for refrigerators was developed by LBNL (Szydlowski 

and Cleary 1988). If EnergyGuide labels are not used, it is important that the same refrigerator 

audit procedures are used for both the Pre- and Post-Retrofit cases to ensure a fair comparison. 

If EnergyGuide labels are available for dishwashers or clothes washers, then the BA Analysis 

Spreadsheet shall be used to estimate annual energy use. If EnergyGuide labels cannot be 

located or do not exist for certain major appliances (e.g., ovens and clothes dryers), the default 

energy factors in Tables 11 through 12 and 14 through 17 shall be used. These defaults were 

derived from historical appliance efficiency studies (Wenzel et al. 1997, DOE 2004b, EPRI 

1986) and technical support documents for recent changes to Federal appliance standards (DOE 

1993, DOE 2000b). If the specific equipment type is not listed in the default tables, the 

efficiency may either be interpolated based on listed equipment or estimated using the original 

reference sources. The default efficiencies must be used in conjunction with the BA Analysis 

Spreadsheet to estimate annual electricity and hot water use. 

Operating hours estimated through occupant surveys or interviews may be useful for determining 

the cost-effectiveness of replacing certain appliances and electronic equipment for a particular 

homeowner. However, the standard operating conditions specified for the Benchmark shall be 

used for the purpose of calculating and reporting whole-house energy savings for the PostRetrofit Case. 

Table 14. Default Gas Clothes Dryer Characteristics (Assumes Typical 1990 

Clothes Washer Capacity and Remaining Moisture Content) 

Equipment Characteristics 

Energy 

Factor 

(lb/kWh) 

Cool-down mode, intermittent ignition, automatic termination 

control, improved door seal, well insulated 2.67 

Cool-down mode, intermittent ignition, timer control, improved door 

seal, well insulated 2.40 

No cool-down mode, pilot light, timer control, poor door seal, 

poorly insulated 2.00 

22
Table 15. Default Electric Clothes Dryer Characteristics (Assumes Typical 1990 Clothes 

Washer Capacity and Remaining Moisture Content) 

Equipment Characteristics Energy Factor 

(lb/kWh) 

Cool-down mode, automatic termination control, improved door 

seal, well insulated 2.75 

No cool-down mode, timer control, poor door seal, poorly 

insulated 2.60 

Table 16. Default Gas Oven / Cooktop Characteristics 

Equipment Characteristics Energy Factor Annual Gas Energy 

(therms/yr) 

Cooktop: intermittent ignition, sealed burner 

Oven: spark ignition, not self cleaning, 

improved door seals, reduced vent rate, highdensity insulation 

Cooktop: 42.0% 

Oven: 6.2% 

Cooktop: 17 

Oven: 18 

Cooktop: intermittent ignition, open burner 

Oven: electric glo-bar ignition, self cleaning 

Cooktop: 40.0% 

Oven: 5.8% 

Cooktop: 18 

Oven: 19 (+80 kWh)

Cooktop: pilot lights 

Oven: pilot light, not self-cleaning, standard 

door seals, standard vent rate, standard 

insulation 

Cooktop: 18.8% 

Oven: 3.5% 

Cooktop: 39 

Oven: 36 

23
Table 17. Default Electric Oven / Cooktop Characteristics 

Equipment Characteristics Energy Factor Annual Electric 

Energy (kWh/yr) 

Cooktop: reflective pans, flat coil elements 

Oven: self-cleaning, improved door seals 

Cooktop: 77.7% 

Oven: 10.2% 

Cooktop: 270 

Oven: 349 

Cooktop: solid disc elements 

Oven: not self-cleaning, improved door seals, 

reduced vent rate, high-density insulation 

Cooktop: 74.2% 

Oven: 12.1% 

Cooktop: 282 

Oven: 293 

Cooktop: non-reflective pans, rounded coil 

elements 

Oven: not self-cleaning, standard door seals, 

standard vent rate, standard insulation 

Cooktop: 73.7% 

Oven: 10.9% 

Cooktop: 284 

Oven: 326 

In most cases, Miscellaneous Electric Loads (MELs) shall be treated as a constant function of 

finished floor area, regardless of the actual MELs present in the Pre-Retrofit Case (Equation 7). 

A multiplier is applied if the house is located in one of the four most populated states as 

determined in the EIA Residential Energy Consumption Survey (RECS) (DOE 2001). 

Multipliers for these four states were estimated based on the final electric end-use regression 

equations developed for the 2001 RECS, substituting national average values for known housing 

characteristics and physical traits of the occupants (such as number of bedrooms, number of 

ceiling fans, and age of homeowner) and removing end-uses that are treated separately in this 

report (such as lighting and clothes dryer). The multiplier is 1.0 for most states because 

insufficient information is available about the magnitude of MELs in those states. 

Equation 7: MEL = (2803 + 0.316 x FFA + 194 x Nbr) x Fs, 

where: 

 MEL = miscellaneous electric loads for the Pre-Retrofit Case (kWh/yr) 

 FFA = finished floor area (ft2

) 

 Nbr = number of bedrooms 

 Fs = state multiplier (New York = 0.82, California = 0.77, Florida = 0.94, 

 Texas = 1.11, all others = 1.00). 

Alternatively, if MEL improvements are included in the retrofit package, analysts may use the 

more detailed methodology developed for new construction (Hendron and Eastment 2006), 

which allows energy savings credit for replacement of small appliances and reduction of standby 

losses. This methodology is automated in the BA MEL Analysis Spreadsheet 

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

24
The fraction of end-use energy converted into internal sensible and latent load is shown in Table 

18. 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. 

Table 18. Default Internal Loads from Appliances and 

Small Electric End-uses in the Pre-Retrofit Case 

Appliance Sensible Load 

Fraction 

Latent Load Fraction 

Refrigerator 1.00 0.00 

Freezer 1.00 0.00 

Clothes Washer 0.80 0.00 

Clothes Dryer (Electric) 0.15 0.05 

Clothes Dryer (Gas) 1.00 (Electric) 

0.10 (Gas) 

0.00 (Electric) 

0.05 (Gas) 

Dishwasher (eight place settings) 0.60 0.15 

Range (Electric) 0.40 0.30 

Range (Gas) 0.30 0.20 

Plug-In Lighting 1.00 0.00 

Miscellaneous Electric Loads 0.66 0.02 

The hourly, normalized load shape for combined residential equipment (Figure 7) is based on the 

results of the End-Use Load and Consumer Assessment Program (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 MELs (Figures 8 through13. Numerical values associated with these profiles can be found 

in the BA Analysis Spreadsheet posted on the Building America web site 

(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 (Figures 1 and 2). The profile for plug-in lighting is the same as 

the profile for hard-wired lighting presented in Figure 5. 

25
All hourly end-use profiles were taken from the ELCAP study, except the profile for 

Miscellaneous Electric 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. Because the MEL profile is based on a 

residual, it is susceptible to greater systematic errors and may be less realistic than the profiles 

for major appliances. These end-use profiles are the same as those used for analyzing new 

construction. Internal sensible and latent heat gains from appliances and plug loads shall be 

modeled using the same profiles used for end-use consumption. Appliance loads may be 

modeled in either the living spaces or bedroom spaces, depending on their location in the house. 

Large end uses in the Pre-Retrofit Case that are not part of typical houses (such as swimming 

pools, Jacuzzis, and workshops) should not be explicitly included in the models for either the 

Pre- or Post-Retrofit Case. 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 7. Total combined residential equipment profile (Pratt et al. 1989) 

26
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 8. Refrigerator and freezer 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 9. Clothes washer normalized machine energy-use profile (Pratt et al. 1989) 

27
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 10. 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 11. Dishwasher normalized energy use profile (Pratt et al. 1989) 

28
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 12. 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 13. Miscellaneous electric load normalized energy-use profile 

29
Site Generation 

If the Pre-Retrofit Case includes site electricity generation equipment, such as a fuel cell, 

photovoltaic system, or wind turbine, then the total energy production shall be calculated using a 

generally accepted engineering methodology. 

Modeling the Post-Retrofit Case 

The Post-Retrofit Case is modeled either as-designed or as-built, depending on the status of the 

project. All parameters for the Post-Retrofit model shall be based on final design specifications 

or measured data, with the following exceptions and clarifications: 

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

improvements shall be the same as the Pre-Retrofit Case. 

• The effective leakage area for the Post-Retrofit Case shall be calculated based on blowerdoor 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, Section 5, 

and ASHRAE Standard 136, Section 4. It is recommended that blower-door measurements 

be supplemented with tracer-gas testing when possible. 

• In order to treat mechanical ventilation in a neutral manner, additional air exchange resulting 

from mechanical ventilation shall be assumed for the model of the Post-Retrofit Case if it 

does not meet the ventilation guidelines of ASHRAE Standard 62.2-2004 (ASHRAE 2004b) 

for existing homes based on natural infiltration plus any existing mechanical ventilation 

system. The same approach used for Pre-Retrofit Case shall be used to calculate 

“supplemental” mechanical ventilation (Equation 5) based on a simple continuous exhaust 

fan designed to raise the total ventilation rate to the minimum values specified in Equation 

4.1a of ASHRAE Standard 62.2-2004, taking into account any infiltration credit allowed 

under Section 4.1.3 and the actual mechanical ventilation system (if any) present in the 

house. Mechanical ventilation shall be combined with natural infiltration in accordance with 

Section 4.4 of ASHRAE Standard 136 to determine an approximate combined effective air 

change rate. The additional fan energy use associated with supplemental mechanical 

ventilation for the Post-Retrofit Case shall be calculated by multiplying the supplemental 

ventilation rate by 3.942 kWh/cfm (Equation 6). This energy shall be added to the energy 

used by any ventilation fan present in the house. 

• For cooling equipment, the energy efficiency ratio (EER) along with part-load performance 

characteristics should be used in the annual simulation whenever possible. SEER is less 

desirable for an annual simulation, but is often the only information that is publicly available 

about a cooling system. If the actual EER for the Post-Retrofit Case is not readily available, 

Equation 8 may be used to make an approximate conversion from SEER to EER (Wassmer 

2003). 

 Equation 8: 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 Post-Retrofit Case must take 

30
these effects into account using operating conditions based on rules developed for DOE 

residential appliance standards (DOE 1999) 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 9: 

Equation 9: 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

. 

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

of annual dryer cycles, using Equation 10: 

Equation 10: 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 11: 

Equation 11: Dishwasher cycles per year = (215) x (1⁄2 + Nbr/6). 

The BA 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 different from the test values 

(140oF and 60oF/50oF), 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 1993). 

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 Post-Retrofit 

energy use for cooking is the same as the Pre-Retrofit case. 

• Modifications to the Pre-Retrofit lighting profile and operating hours because of occupancy 

sensors or other controls may be considered for the Post-Retrofit Case, 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 explicitly included in the models for either the Pre- or PostRetrofit Case. The efficiency of these end uses should be addressed in a separate analysis. 

31
• For the Post-Retrofit Case, all site electricity generation is credited regardless of energy 

source. Residential-scale photovoltaic systems, wind turbines, fuel cells, and microcogeneration 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 report). 

Operating Conditions 

For consistency within Building America, operating conditions and other assumptions for 

existing homes shall be the same as those documented in the Benchmark for new construction 

(www.eere.energy.gov/buildings/building_america/pa_resources.html). The Benchmark 

guidelines will be updated occasionally (every 2 or 3 years), so the most recent release posted on 

the BA web site should be consulted before developing the existing homes model. 

The following operating conditions and other assumptions, based on the 2005 Benchmark 

Update, shall apply to both the Pre- and Post-Retrofit Cases. They are intended to represent the 

behavior of a typical set of occupants, not the current occupants of the house, because Building 

America is interested in estimating long-term energy savings of improvements to existing homes. 

The operating conditions are the same for both existing homes and new construction and 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. 

• The following standard thermostat set points shall be used: 

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

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

Actual thermostat set points used by the occupants may be used for the purpose of costbenefit analysis, but not as part of the formal energy-savings analysis reported to Building 

America. 

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

In situations in which there is a cooling load, the outdoor temperature is below the indoor 

temperature, and the windows are not already open, then the probability of the windows 

being opened shall be set at a constant 50%. The natural ventilation rate shall be 5 ACH 

unless each living area and bedroom provides at least two openings on different orientations 

and the net area of openings exceeds 12% of the floor area of the house (cross-ventilation), in 

which case a natural ventilation rate of 7 ACH shall be used. If there are local circumstances 

that would tend to discourage window operation (pollution, security, community standards, 

etc), then it is acceptable to use a lower probability than 50%, as long as the same natural 

ventilation schedule is applied to both the Pre- and Post-Retrofit Cases. 

• 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. 

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

sections. These loads are not necessarily the same for the Pre- and Post-Retrofit Cases; 

32
therefore, they are not considered operating conditions for the purposes of Building America 

performance analysis. 

• 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 12. 

Equation 12: Number of occupants = 0.5 x Nbr + 1.5 

 where: 

Nbr = Number of bedrooms. 

Sensible and latent gains from occupants shall be accounted for separately, and different 

loads shall be applied in different space types for multi-zone models (Table 19). The 

occupant heat gains are based on ASHRAE recommendations (ASHRAE 2005). The 

average hourly occupancy profile is shown in Figure 14, and an example set of detailed 

hourly occupancy curves is shown in Figure 15. Detailed occupancy profiles based on 

different day and room types are available in spreadsheet format on the Building America 

Web site (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. 

• 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. The actual thermal mass present in the house is not used for Building 

America existing homes analysis. 

Table 19. Peak Sensible and Latent Heat Gain from Occupants (ASHRAE 2005) 

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 

Single Zone Internal Load (Btu/person/hr) 

Sensible Load 220 

Latent Load 164 

33
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 14. Average hourly load profile from occupants for all 

day-types and family types (16.5 hours/day/person total) 

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 15. Detailed hourly load profiles resulting from 

occupants being in different parts of the house on weekdays 

(WD) and weekends (WE) 

• Weather data shall be based on typical meteorological year (TMY2) data (NREL 1995) from 

1961 through 1990 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 design 

temperatures (WDT) based on TMY2 data or the 2005 ASHRAE Handbook of Fundamentals 

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

34
Step 1. MAT Basis 

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

than 71.5°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 two consecutive months in which 

the heating system is enabled the first month and the cooling system is enabled 

the following month, or vice versa, then both the heating system and the cooling 

system shall be enabled for both of these months. 

These heating and cooling season procedures are automated in the BA Analysis Spreadsheet 

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

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 existing homes project. 

Table 20 shows an example of a site energy consumption report for a hypothetical project, before 

and after the retrofits are performed. Similar information based on source energy is presented in 

Table 21, along with percent energy savings for each end use. End uses are described in more 

detail in Table 22. 

The “Percent of End Use” column in Table 21 shows the Post-Retrofit energy savings for each 

end use as a fraction of the energy use in the Pre-Retrofit Case. The “Percent of Total” columns 

show the contribution of each end use toward an overall energy-reduction goal. 

Source energy is determined using Equation 13. The site to source multiplier for energy sources 

other than electricity or natural gas is assumed to be 1.0. 

Equation 13: Source MBtu = kWh • 3.412 • Me /1000 + therms • Mg / 10 

 where: 

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

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

35
Table 20. Example Summary of Site Energy Consumption by 

End-use for an Existing Homes Project 

Annual Site Energy 

Pre-Retrofit Post-Retrofit 

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

Space Heating 11,225 0 4,397 0 

Space Cooling 2,732 0 902 0 

DHW 4,837 0 1,351 0 

Lighting 3,110 1,204 

Appliances + MEL 7,646 0 7,436 0 

OA Ventilation 400 400 

Total Usage 29,950 0 15,690 0 

Site Generation 0 7,402 

Net Energy Use 29,950 0 8,289 0 

36
Table 21. Example Summary of Source Energy Consumption 

by End-use for an Existing Homes Project 

Estimated Annual Source 

Energy Source Energy Savings 

Pre-Retrofit Post-Retrofit Percent of Percent of 

End Use (MBtu/yr) (MBtu/yr) End-Use Total 

Space Heating 115 45 61% 23% 

Space Cooling 28 9 67% 6% 

DHW 50 14 72% 12% 

Lighting 32 12 61% 6% 

Appliances + MEL 78 76 3% 1% 

OA Ventilation 4 4 0% 0% 

Total Usage 307 161 48% 48% 

Site Generation 0 -76 25% 

Net Energy Use 307 85 72% 72% 

37
Table 22. End-Use Categories 

End Use Potential Electric Usage Potential Gas Usage 

Space 

Heating 

Supply fan during space heating, heat 

pump, heat-pump supplemental heat, 

water-boiler heating elements, waterboiler circulation pump, electricresistance heating, heat-pump crankcase 

heat, heating-system auxiliary 

Gas furnace, gas boiler, 

gas back-up heat-pump 

supplemental heat, gas 

ignition stand-by 

Space 

Cooling 

Central split-system A/C, packaged A/C 

(window or through-the-wall), supply-an 

energy during space cooling, A/C 

crankcase heat, cooling-system auxiliary 

Gas absorption chiller 

(rare) 

DHW Electric hot water heater, heat-pump 

water heater, hot water circulation pumps 

Gas hot water heater 

Lighting Indoor lighting, outdoor lighting None 

Appliances & 

MEL 

Refrigerator, electric clothes dryer, gas 

clothes dryer (motor), cooking, 

miscellaneous electric loads 

Cooking, gas clothes 

dryer 

OA 

Ventilation 

Ventilation fans, supply-air fan during 

ventilation mode 

None 

Site 

Generation 

Photovoltaic electric generation None 

Table 23 reports energy savings for individual energy efficiency measures applied to the PreRetrofit Case, in terms of site energy, 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 Pre-Retrofit Case (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 Post-Retrofit Case. 

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

energy costs. Peak hourly energy consumption should also be reported Pre- and Post-Retrofit 

for every project. Peak energy is based on the hour with the greatest gas or electric energy 

consumption during the course of 1 year, as determined by the hourly simulation. 

 

 

38
Table 23. Example Measure Savings Report for an Existing Homes Project2

National Average Economics (Local Costs) 

Site Energy Source Energy Energy Cost Energy Cost Measure Package

Increment (kWh) (therms) (MBtu)

Savings 

(%) ($/yr) 

Savings 

(%) ($/yr) 

Savings 

(%) 

Value 

($/yr) 

Savings 

($/yr) 

Pre-Retrofit 29,950 0 306.9 $ 2,995 $ 2,950 

+ Improved walls 27,779 0 284.6 7% $ 2,778 7% $ 2,736 7% $ 190.4 $ 190 

++ Low-E Windows 25,810 0 264.5 14% $ 2,581 14% $ 2,542 13% $ 193.9 $ 384 

++ Smaller A/C (5≥ 4 tons) 25,420 0 260.5 15% $ 2,542 15% $ 2,504 14% $ 38.4 $ 423 

++ Including Basement Wall 

Insulation 25,170 0 257.9 16% $ 2,517 16% $ 2,479 15% $ 24.6 $ 447 

++ Ground Source HP (+DHW) 19,331 0 198.1 35% $ 1,933 35% $ 1,904 35% $ 575.1 $1,023 

++ Solar DHW 17,718 0 181.5 41% $ 1,772 41% $ 1,745 40% $ 158.9 $1,181 

++ Lighting, Appliances and Plug 15,690 0 160.8 48% $ 1,569 48% $ 1,545 47% $ 199.8 $ 1,381 

++ PV (Post-Retrofit) 8,288 0 84.9 72% $ 829 $ 816 72% $ 729.0 $ 2,110 

Acknowledgments 

The author thanks the NREL staff for their ideas and inputs on this project, especially Ren 

Anderson, Paul Torcellini, Ali Jalalzedah, Mark Eastment, and Nancy Wells. The author also 

acknowledges the resources and guidance provided by Ed Pollock and George James of the U.S. 

Department of Energy Building America Program. 

 

2Calculated using national average electric cost = $0.10/kWh and national average gas cost = $0.50/therm. 

39
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of Electric Energy Use in Single-Family Residences in the Pacific Northwest – End-Use 

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Residential Energy Services Network. 

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ASHRAE Transactions, v.94, pt.1, p.1107-1023. 

Wassmer, M. 2003. A Component-Based Model for Residential Air Conditioner and Heat Pump 

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Sourcebook for the U.S. Residential Sector. LBL-40297. Berkeley, CA: Lawrence 

Berkeley National Laboratory. 

42
F1147-E(12/2004) 

REPORT DOCUMENTATION PAGE Form Approved 

OMB No. 0704-0188

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PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION.

1. REPORT DATE (DD-MM-YYYY)

May 2006 

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 Performance Analysis Procedures for Existing 

Homes 

5c. PROGRAM ELEMENT NUMBER

5d. PROJECT NUMBER

NREL/TP-550-38238 

5e. TASK NUMBER

BET6.8004 

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-550-38238 

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NREL 

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11. SPONSORING/MONITORING 

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National Technical Information Service 

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13. SUPPLEMENTARY NOTES

14. ABSTRACT (Maximum 200 Words)

With more than 101 million residential households in the United States today, existing residential buildings represent 

a large potential energy savings. Thousands of these homes are renovated each year, Building America is 

investigating the ways to make existing homes more energy-efficient, based on lessons learned from research in new 

homes. The Building America program is aiming for a 20%–30% reduction in energy use in existing homes by 2020. 

The strategy is to establish technology pathways that reduce energy consumption cost-effectively. The existing 

buildings project focuses on finding ways to adapt the results from the new homes research to retrofit applications in 

existing homes. Research activities include a combination of computer modeling, field demonstrations, and long-term 

monitoring to support the development of integrated approaches to reduce energy use. Analytical tools are being 

developed to guide designers and builders in selecting the best approaches. DOE partners with the EPA to increase 

energy efficiency in existing homes through the Home Performance with ENERGY STAR® program. 

15. SUBJECT TERMS

Building America; existing homes; performance analysis procedures; residential buildings; energy efficiency 

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

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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.

Research and Development 

of Buildings

Our nation’s buildings consume more 

energy than any other sector of the 

U.S. economy, including transportation 

and industry. Fortunately, the opportunities to reduce building energy use—

and the associated environmental 

impacts—are significant.

DOE’s Building Technologies Program 

works to improve the energy efficiency 

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

building practices. The program

focuses on two key areas:

• Emerging Technologies 

Research and development of the 

next generation of energy-efficient 

components, materials, and 

equipment

• Technology Integration

Integration of new technologies 

with innovative building methods 

to optimize building performance 

and savings

For more information contact:

EERE Information Center

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

www.eere.energy.gov

An electronic copy of this publication is 

available on the Building America Web 

site at www.buildingamerica.gov

U.S. Department of Energy

Energy Efficiency

and Renewable Energy

Building America Program

George S. James • New Construction • 202-586-9472 • fax: 202-586-8134 • e-mail: George.James@ee.doe.gov

Terry Logee • Existing Homes • 202-586-1689 • fax: 202-586-4617 • e-mail: terry.logee@ee.doe.gov

Lew Pratsch • Integrated Onsite Power • 202-586-1512 • fax: 202-586-8185 • e-mail: Lew.Pratsch@hq.doe.gov

Building America Program • Office of Building Technologies, EE-2J • U.S. Department of Energy • 1000 Independence Avenue, S.W. • 

Washington, D.C. 20585-0121 • www.buildingamerica.gov

Building Industry Research Alliance (BIRA)

Robert Hammon • ConSol • 7407 Tam O’Shanter Drive #200 • Stockton, CA 95210-3370 • 209-473-5000 • fax: 209-474-0817 • 

e-mail: Rob@consol.ws • www.bira.ws

Building Science Consortium (BSC)

Betsy Pettit • Building Science Consortium (BSC) • 70 Main Street • Westford, MA 01886 • 978-589-5100 • fax: 978-589-5103 • 

e-mail: Betsy@buildingscience.com • www.buildingscience.com

Consortium for Advanced Residential Buildings (CARB)

Steven Winter • Steven Winter Associates, Inc. • 50 Washington Street • Norwalk, CT 06854 • 203-857-0200 • fax: 203-852-0741 • 

e-mail: swinter@swinter.com • www.carb-swa.com

Davis Energy Group

David Springer • Davis Energy Group • 123 C Street • Davis, CA 95616 • 530-753-1100 • fax: 530-753-4125 •

e-mail: springer@davisenergy.com • deg@davisenergy.com • www.davisenergy.com/index.html

IBACOS Consortium

Brad Oberg • IBACOS Consortium • 2214 Liberty Avenue • Pittsburgh, PA 15222 • 412-765-3664 • fax: 412-765-3738 •

e-mail: boberg@ibacos.com • www.ibacos.com

Industrialized Housing Partnership (IHP)

Subrato Chandra • Florida Solar Energy Center • 1679 Clearlake Road • Cocoa, FL 32922 • 321-638-1412 • fax: 321-638-1439 • 

e-mail: subrato@fsec.ucf.edu • www.baihp.org

National Association of Home Builders (NAHB) Research Center

Tom Kenney • National Association of Home Builders (NAHB) Research Center • 400 Prince George’s Boulevard • 

Upper Marlboro, MD 20774 • 301-430-6246 • fax: 301-430-6180 • toll-free: 800-638-8556 • www.nahbrc.org/ 

National Renewable Energy Laboratory

Ren Anderson • 1617 Cole Boulevard, MS-2722 • Golden, CO 80401 • 303-384-7433 • fax: 303-384-7540 • 

e-mail: ren_anderson@nrel.gov • www.nrel.gov

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Oak Ridge National Laboratory

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