NIST Special Publication 1147 

Benefits and Costs of Energy 

Standard Adoption in New 

Commercial Buildings 

Joshua Kneifel 

http://dx.doi.org/10.6028/NIST.SP.1147 

 

 

 

 

 

 

 

 

 

 

 

 

NIST Special Publication 1147
 

Benefits and Costs of Energy 

Standard Adoption in New 

Commercial Buildings 

Joshua Kneifel 

Applied Economics Office 

Engineering Laboratory 

http://dx.doi.org/10.6028/NIST.SP.1147 

February 2013 

U.S. Department of Commerce 

Rebecca Blank, Acting Secretary 

National Institute of Standards and Technology 

Patrick D. Gallagher, Under Secretary of Commerce for Standards and Technology and Director 
 

 

 

 

 

 

 

Certain commercial entities, equipment, or materials may be identified in this 

document in order to describe an experimental procedure or concept adequately. 

Such identification is not intended to imply recommendation or endorsement by the 

National Institute of Standards and Technology, nor is it intended to imply that the 

entities, materials, or equipment are necessarily the best available for the purpose. 

National Institute of Standards and Technology Special Publication 1147 

Natl. Inst. Stand. Technol. Spec. Publ. 1147, 170 pages (February 2013) 

http://dx.doi.org/10.6028/NIST.SP.1147 

CODEN: NSPUE2 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Abstract 

Energy efficiency requirements in current energy codes for commercial buildings vary 

across states, and many states have not yet adopted the newest energy standard edition. 

As of December 2011, states have adopted energy codes ranging across all editions of 

American Society of Heating, Refrigerating and Air-Conditioning Engineers Energy 

Standard for Buildings Except Low-Rise Residential Buildings (ASHRAE) 90.1 

(-1999, -2001, -2004, and -2007). Some states do not have a code requirement for energy 

efficiency, leaving it up to the locality or jurisdiction to set its own requirements. This 

study considers the impacts that the adoption of newer, more stringent energy codes for 

commercial buildings would have on building energy use, operational energy costs, 

building life-cycle costs, and cradle-to-grave energy-related carbon emissions. 

The results of this report are based on analysis of the Building Industry Reporting and 

Design for Sustainability (BIRDS) database, which includes 12 540 whole building 

energy simulations covering 11 building types in 228 cities across all U.S. states for 9 

study period lengths. The performance of buildings designed to meet current state energy 

codes is compared to their performance when meeting alternative building energy 

standard editions to determine whether more stringent energy standard editions are costeffective in reducing energy consumption and energy-related carbon emissions. Each 

state energy code is also compared to a “Low Energy Case” (LEC) building design that 

increases energy efficiency beyond the ASHRAE 90.1-2007 design. The estimated 

savings for each of the building types are aggregated using new commercial building 

construction data to calculate the magnitude of the available savings that a state may 

realize if it were to adopt a more energy efficient standard as its state energy code. 

Keywords 

Building economics; economic analysis; life-cycle costing; life-cycle assessment; energy 

efficiency; commercial buildings 
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Preface 

This study was conducted by the Applied Economics Office in the Engineering 

Laboratory (EL) at the National Institute of Standards and Technology (NIST). The 

study is designed to assess the energy consumption, life-cycle cost, and energy-related 

carbon emissions impacts from the adoption of new state energy codes based on more 

stringent building energy standard editions. The intended audience is researchers and 

policy makers in the commercial building sector, and others interested in building energy 

efficiency. 

Disclaimer 

The policy of the National Institute of Standards and Technology is to use metric units in 

all of its published materials. Because this report is intended for the U.S. construction 

industry that uses U.S. customary units, it is more practical and less confusing to include 

U.S. customary units as well as metric units. Measurement values in this report are 

therefore stated in metric units first, followed by the corresponding values in U.S. 

customary units within parentheses. 

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Acknowledgements 

The author wishes to thank all those who contributed ideas and suggestions for this 

report. They include Ms. Barbara Lippiatt and Dr. Robert Chapman of EL’s Applied 

Economics Office, Dr. William Healy of EL’s Energy and Environment Division, and Dr. 

Nicos S. Martys of EL’s Materials and Structural Systems Division. A special thanks to 

Mr. Nicholas Long and the EnergyPlus Team for generating the initial energy simulations 

for this project. Thanks to Mr. Brian Presser for adapting the energy simulations to meet 

the study requirements and generating the final simulations used in the database. Thanks 

to Mr. Nathaniel Soares for developing the initial version of the BIRDS database, and to 

Ms. Priya Lavappa for enhancing the database for the current analysis. The author would 

like to thank the NIST Engineering Laboratory for its support of the project. 

Author Information 

Joshua D. Kneifel 

Economist 

National Institute of Standards and Technology 

Engineering Laboratory 

100 Bureau Drive, Mailstop 8603 

Gaithersburg, MD 20899-8603 

Tel.: 301-975-6857 

Email: joshua.kneifel@nist.gov 

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Table of Contents
 

Abstract.............................................................................................................................. v
 

List of Acronyms .......................................................................................................... xxiii
 

Executive Summary ...................................................................................................... xxv
 

Preface.............................................................................................................................. vii
 

Acknowledgements .......................................................................................................... ix
 

Author Information ......................................................................................................... ix
 

List of Figures.................................................................................................................. xv
 

List of Tables ................................................................................................................. xvii
 

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

1.1 Background and Purpose...................................................................................... 1
 

1.2 Literature Review ................................................................................................. 2
 

1.3 Approach .............................................................................................................. 3
 

2 Study Design .............................................................................................................. 5
 

2.1 Building Types ..................................................................................................... 5
 

2.2 Building Designs .................................................................................................. 5
 

2.3 Study Period Lengths ........................................................................................... 8
 

3 Cost Data.................................................................................................................... 9
 

3.1 First Costs............................................................................................................. 9
 

3.2 Future Costs........................................................................................................ 11
 

4 Building Stock Data ................................................................................................ 15
 

4.1 Databases............................................................................................................ 15
 

4.2 Weighting Factors .............................................................................................. 15
 

5 Analysis Approach .................................................................................................. 17
 

5.1 Energy Use ......................................................................................................... 17
 

5.2 Life-Cycle Costing ............................................................................................. 17
 

5.3 Carbon Assessment ............................................................................................ 18
 

5.4 Analysis Metrics................................................................................................. 19
 

5.5 States Selected for Detailed Analysis................................................................. 20
 

6 Alaska....................................................................................................................... 21
 

6.1 Percentage Savings............................................................................................. 22
 

6.1.1 Energy Use ................................................................................................ 22
 

6.1.2 Energy Costs ............................................................................................. 23
 

6.1.3 Energy-related Carbon Emissions............................................................. 24
 

6.1.4 Life-Cycle Costs ....................................................................................... 25
 

6.1.5 City Comparisons...................................................................................... 25
 

6.2 Total Savings...................................................................................................... 28
 

6.2.1 Energy Use ................................................................................................ 28
 

6.2.2 Energy Costs ............................................................................................. 30
 

6.2.3 Energy-related Carbon Emissions............................................................. 31
 

6.2.4 Life-Cycle Costs ....................................................................................... 33
 

6.3 State Summary ................................................................................................... 34
 

7 Colorado................................................................................................................... 37
 

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7.1 Percentage Savings............................................................................................. 38
 

7.1.1 Energy Use ................................................................................................ 38
 

7.1.2 Energy Costs ............................................................................................. 39
 

7.1.3 Energy-related Carbon Emissions............................................................. 40
 

7.1.4 Life-Cycle Costs ....................................................................................... 40
 

7.1.5 City Comparisons...................................................................................... 41
 

7.2 Total Savings...................................................................................................... 43
 

7.2.1 Energy Use ................................................................................................ 44
 

7.2.2 Energy Costs ............................................................................................. 46
 

7.2.3 Energy-related Carbon Emissions............................................................. 47
 

7.2.4 Life-Cycle Costs ....................................................................................... 48
 

7.3 State Summary ................................................................................................... 50
 

8 Florida ...................................................................................................................... 53
 

8.1 Percentage Savings............................................................................................. 53
 

8.1.1 Statewide Building Comparison ............................................................... 54
 

8.1.2 City Comparisons...................................................................................... 55
 

8.2 Total Savings...................................................................................................... 56
 

8.2.1 Energy Use ................................................................................................ 56
 

8.2.2 Energy Costs ............................................................................................. 58
 

8.2.3 Energy-related Carbon Emissions............................................................. 60
 

8.2.4 Life-Cycle Costs ....................................................................................... 61
 

8.3 State Summary ................................................................................................... 62
 

9 Maryland ................................................................................................................. 63
 

9.1 Percentage Savings............................................................................................. 64
 

9.2 Total Savings...................................................................................................... 65
 

9.2.1 Energy Use ................................................................................................ 65
 

9.2.2 Energy Costs ............................................................................................. 67
 

9.2.3 Energy-related Carbon Emissions............................................................. 69
 

9.2.4 Life-Cycle Costs ....................................................................................... 70
 

9.3 State Summary ................................................................................................... 71
 

10 Oregon...................................................................................................................... 73
 

10.1 Percentage Savings............................................................................................. 73
 

10.1.1 Statewide Building Comparison .......................................................... 74
 

10.1.2 City Comparisons ................................................................................ 75
 

10.2 Total Savings...................................................................................................... 76
 

10.2.1 Energy Use .......................................................................................... 76
 

10.2.2 Energy Costs ........................................................................................ 78
 

10.2.3 Energy-related Carbon Emissions ....................................................... 80
 

10.2.4 Life-Cycle Costs .................................................................................. 81
 

10.3 State Summary ................................................................................................... 82
 

11 Tennessee ................................................................................................................. 83
 

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11.1 Percentage Savings............................................................................................. 84
 

11.1.1 Energy Use .......................................................................................... 84
 

11.1.2 Energy Costs ........................................................................................ 85
 

11.1.3 Energy-related Carbon Emissions Reduction...................................... 86
 

11.1.4 Life-Cycle Costs .................................................................................. 86
 

11.1.5 City Comparisons ................................................................................ 87
 

11.2 Total Savings...................................................................................................... 89
 

11.2.1 Energy Use .......................................................................................... 90
 

11.2.2 Energy Costs ........................................................................................ 91
 

11.2.3 Energy-related Carbon Emissions ....................................................... 93
 

11.2.4 Life-Cycle Costs .................................................................................. 94
 

11.3 State Summary ................................................................................................... 96
 

12 Wisconsin ................................................................................................................. 97
 

12.1 Percentage Savings............................................................................................. 97
 

12.1.1 Statewide Building Comparison .......................................................... 98
 

12.1.2 City Comparisons ................................................................................ 99
 

12.2 Total Savings.................................................................................................... 100
 

12.2.1 Energy Use ........................................................................................ 100
 

12.2.2 Energy Costs ...................................................................................... 101
 

12.2.3 Energy-related Carbon Emissions ..................................................... 103
 

12.2.4 Life-Cycle Costs ................................................................................ 104
 

12.3 State Summary ................................................................................................. 105
 

13 Total Savings Comparisons for Selected States ................................................. 107
 

14 Savings from Nationwide Adoption of Low Energy Case ................................. 111
 

14.1 State Comparisons............................................................................................ 111
 

14.1.1 3-Story Office Building ..................................................................... 112
 

14.2 Results by Study Period Length ....................................................................... 115
 

14.3 Results by Building Type ................................................................................. 118
 

14.4 Results by Climate Zone .................................................................................. 119
 

14.5 Low Energy Case Summary............................................................................. 123
 

15 Savings from Nationwide Adoption of ASHRAE 90.1-2007.............................. 125
 

15.1 State Comparisons............................................................................................ 126
 

15.1.1 3-Story Office Building ..................................................................... 126
 

15.2 Results by Study Period Length ....................................................................... 129
 

15.3 Results by Building Type ................................................................................. 132
 

15.4 Results by Climate Zone .................................................................................. 133
 

15.5 ASHRAE 90.1-2007 Summary ......................................................................... 138
 

16 Discussion............................................................................................................... 141
 

16.1 Key Findings .................................................................................................... 141
 

16.2 Limitations and Future Research...................................................................... 143
 

References ...................................................................................................................... 147
 

A Building Type, New Construction, and Emissions Rates .................................. 151
 

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B BIRDS Results by Building Type for the Nationwide Adoption of the LEC and
 

ASHRAE 90.1-2007 Designs ............................................................................. 157
 

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List of Figures 

Figure 2-1 State Commercial Energy Codes ..................................................................... 7
 

Figure 2-2 Cities and ASHRAE Climate Zones.................................................................. 8
 

Figure 14-1 States that have Adopted ASHRAE 90.1-2001 or No Energy Code........... 111
 

Figure 14-2 Average Energy Use Savings by State, 3-Story Office Building,
 

10-Year ...................................................................................................... 113
 

Figure 14-3 Average Energy Cost Savings by State, 3-Story Office Building,
 

Figure 14-4 Average Energy-related Carbon Emissions Reduction by State, 3-Story
 

Figure 14-5 Average Life-Cycle Cost Savings by State, 3-Story Office Building,
 

10-Year ...................................................................................................... 113
 

Office Building, 10-year ........................................................................... 114
 

10-Year ...................................................................................................... 114
 

Figure 14-6 Nationwide Average Percentage Change in Life-cycle Costs from
 

Nationwide Adoption of the LEC Design by Building Type and Study
 

Period Length ............................................................................................ 118
 

Figure 15-1 States that have Adopted ASHRAE 90.1-2001 or No Energy Code........... 125
 

Figure 15-2 States that have Adopted ASHRAE 90.1-2007 ........................................... 126
 

Figure 15-3 Average Energy Use Savings by State, 3-Story Office Building,
 

10-Year ...................................................................................................... 127
 

Figure 15-4 Average Energy Cost Savings by State, 3-Story Office Building,
 

10-Year ...................................................................................................... 128
 

Figure 15-5 Average Carbon Reduction by State, 3-Story Office Building, 10-Year... 128
 

Figure 15-6 Average Life-Cycle Cost Savings by State, 3-Story Office Building,
 

10-Year ...................................................................................................... 129
 

Figure 15-7 Percentage Change in Life-Cycle Cost from Nationwide Adoption of
 

ASHRAE 90.1-2007 by Study Period Length and ASHRAE Climate
 

Zone........................................................................................................... 138
 

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List of Tables 

Table 2-1 Building Characteristics .................................................................................... 5
 

Table 2-2 Energy Code by State and City Exception ........................................................ 6
 

Table 3-1 Energy Efficiency Component Requirements for Alternative Building
 

Designs ........................................................................................................ 10
 

Table 3-2 HVAC Energy Efficiency Requirements for Alternative Building Designs ... 11
 

Table 4-1 New Commercial Building Construction (U.S., 2003 through 2007) .............. 16
 

Table 5-1 Greenhouse Gas Global Warming Potentials .................................................. 19
 

Table 5-2 Selection Criteria Values for States Analyzed in Detail (2003 to 2007)......... 20
 

Table 6-1 Average Annual Energy Use by Building Type and Energy Code, Alaska .... 21
 

Table 6-2 Average Percentage Change in Energy Use from Adoption of Newer
 

Codes, Alaska .............................................................................................. 22
 

Table 6-3 Average Percentage Change in Energy Costs, 10-Year, Alaska ..................... 23
 

Table 6-4 Average Percentage Change in Energy-related Carbon Emissions, 10­

Year, Alaska ................................................................................................ 24
 

Table 6-5 Average Percentage Change in Life-Cycle Costs, 10-Year, Alaska ............... 25
 

Table 6-6 Average Percentage Change in Energy Use from Adoption of Newer
 

Codes by City, Alaska ................................................................................. 26
 

Table 6-7 Average Percentage Change in Energy Costs by City, 10-Year, Alaska ........ 26
 

Table 6-8 Average Percentage Change in Carbon Emissions by City, 10-Year,
 

Alaska .......................................................................................................... 27
 

Table 6-9 Average Percentage Change in Life-Cycle Costs by City, 10-Year, Alaska .. 27
 

Table 6-10 Average Per Unit Change in Annual Energy Use, Alaska ............................ 28
 

Table 6-11 Statewide Change in Annual Energy Use for One Year of Construction,
 

Alaska .......................................................................................................... 29
 

Table 6-12 Average Per Unit Change in Energy Costs, 10-Year, Alaska ....................... 30
 

Table 6-13 Statewide Change in Energy Costs for One Year of Construction,
 

10-Year, Alaska ........................................................................................... 31
 

Table 6-14 Average Per Unit Change in Carbon Emissions, 10-Year, Alaska ............... 32
 

Table 6-15 Statewide Change in Total Carbon Emissions for One Year of
 

Construction, 10-Year, Alaska – Metric Tons ............................................ 33
 

Table 6-16 Average Per Unit Change in Life-Cycle Costs, 10-Year, Alaska ................. 33
 

Table 6-17 Statewide Change in Life-Cycle Costs for One Year of Construction,
 

10-Year, Alaska ........................................................................................... 34
 

Table 7-1 Average Annual Energy Use by Building Type and Energy Code,
 

Colorado ...................................................................................................... 37
 

Table 7-2 Average Percentage Change in Energy Use from Adoption of Newer
 

Codes, Colorado .......................................................................................... 38
 

Table 7-3 Average Percentage Change in Energy Costs, 10-Year, Colorado ................. 39
 

Table 7-4 Average Percentage Change in Energy-related Carbon Emissions, 10­

Year, Colorado ............................................................................................ 40
 

Table 7-5 Average Percentage Change in Life-Cycle Costs, 10-Year, Colorado ........... 41
 

Table 7-6 Average Percentage Change in Energy Use from Adoption of Newer
 

Codes by City, Colorado ............................................................................. 42
 

Table 7-7 Average Percentage Change in Energy Costs by City, 10-Year, Colorado .... 42
 

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Table 7-8 Average Percentage Change in Carbon Emissions by City, 10-Year, 

Colorado ...................................................................................................... 43
 

Table 7-9 Average Percentage Change in Life-Cycle Costs by City, 10-Year,
 

Colorado ...................................................................................................... 43
 

Table 7-10 Average Per Unit Change in Annual Energy Use, Colorado ........................ 44
 

Table 7-11 Statewide Change in Annual Energy Use for One Year of Construction,
 

Colorado ...................................................................................................... 45
 

Table 7-12 Average Per Unit Change in Energy Costs, 10-Year, Colorado ................... 46
 

Table 7-13 Statewide Change in Energy Costs for One Year of Construction, 10­

Year, Colorado ............................................................................................ 47
 

Table 7-14 Average Per Unit Change in Carbon Emissions, 10-Year, Colorado............ 47
 

Table 7-15 Statewide Change in Total Carbon Emissions for One Year of
 

Construction, 10-Year, Colorado – Metric Tons......................................... 48
 

Table 7-16 Average Per Unit Change in Life-Cycle Costs, 10-Year, Colorado.............. 49
 

Table 7-17 Statewide Change in Life-Cycle Costs for One Year of Construction,
 

10-Year, Colorado ....................................................................................... 50
 

Table 8-1 Average Annual Energy Use by Building Type and Energy Code, Florida ... 53
 

Table 8-2 Average Percentage Change from Adoption of a Newer Code, 10-Year,
 

Florida ......................................................................................................... 54
 

Table 8-3 Average Percentage Change in Energy Use from Adoption of Newer
 

Codes by City, 10-Year, Florida ................................................................. 55
 

Table 8-4 Average Per Unit Change in Annual Energy Use, Florida.............................. 57
 

Table 8-5 Statewide Change in Annual Energy Use for One Year of Construction,
 

Florida ......................................................................................................... 58
 

Table 8-6 Average Per Unit Change in Energy Costs, 10-Year, Florida......................... 59
 

Table 8-7 Statewide Change in Energy Costs for One Year of Construction,
 

10-Year, Florida .......................................................................................... 59
 

Table 8-8 Average Per Unit Change in Carbon Emissions, 10-Year, Florida ................. 60
 

Table 8-9 Statewide Change in Total Carbon Emissions (t) for One Year of
 

Construction, 10-Year, Florida – Metric Tons ............................................ 61
 

Table 8-10 Average Per Unit Change in Life-Cycle Costs, 10-Year, Florida ................. 61
 

Table 8-11 Statewide Change in Life-Cycle Costs for One Year of Construction,
 

10-Year, Florida .......................................................................................... 62
 

Table 9-1 Average Annual Energy Use by Building Type and Energy Code,
 

Maryland ..................................................................................................... 63
 

Table 9-2 Average Percentage Change from Adoption of a Newer Code, 10 Year,
 

Maryland ..................................................................................................... 64
 

Table 9-3 Average Per Unit Change in Annual Energy Use, Maryland.......................... 66
 

Table 9-4 Statewide Change in Annual Energy Use for One Year of Construction,
 

Maryland ..................................................................................................... 67
 

Table 9-5 Average Per Unit Change in Energy Costs, 10-Year, Maryland..................... 68
 

Table 9-6 Statewide Change in Energy Costs for One Year of Construction,
 

10-Year, Maryland ...................................................................................... 68
 

Table 9-7 Average Per Unit Change in Carbon Emissions, 10-Year, Maryland ............. 69
 

Table 9-8 Statewide Change in Total Carbon Emissions for One Year of
 

Construction, 10-Year, Maryland – Metric Tons ........................................ 70
 

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Table 9-9 Average Per Unit Change in Life-Cycle Costs, 10-Year, Maryland ............... 70
 

Table 9-10 Statewide Change in Life-Cycle Costs for One Year of Construction,
 

10-Year, Maryland ...................................................................................... 71
 

Table 10-1 Average Annual Energy Use by Building Type and Energy Code,
 

Oregon ......................................................................................................... 73
 

Table 10-2 Average Percentage Change in Energy Use from Adoption of a Newer
 

Code, 10-Year, Oregon ............................................................................... 74
 

Table 10-3 Average Percentage Change in Energy Use from Adoption of Newer
 

Codes by City, 10-Year, Oregon ................................................................. 76
 

Table 10-4 Average Per Unit Change in Annual Energy Use, Oregon ........................... 77
 

Table 10-5 Statewide Change in Annual Energy Use for One Year of Construction,
 

Oregon ......................................................................................................... 78
 

Table 10-6 Average Per Unit Change in Energy Costs, 10-Year, Oregon ...................... 79
 

Table 10-7 Statewide Change in Energy Costs for One Year of Construction,
 

10-Year, Oregon .......................................................................................... 80
 

Table 10-8 Average Per Unit Change in Carbon Emissions, 10-Year, Oregon .............. 80
 

Table 10-9 Statewide Change in Total Carbon Emissions for One Year of
 

Construction, 10-Year, Oregon – Metric Tons ........................................... 81
 

Table 10-10 Average Per Unit Change in Life-Cycle Costs, 10-Year, Oregon .............. 81
 

Table 10-11 Statewide Change in Life-Cycle Costs for One Year of Construction,
 

10-Year, Oregon .......................................................................................... 82
 

Table 11-1 Average Annual Energy Use by Building Type and Energy Code,
 

Tennessee .................................................................................................... 83
 

Table 11-2 Average Percentage Change in Energy Use from Adoption of Newer
 

Codes, Tennessee ........................................................................................ 84
 

Table 11-3 Average Percentage Change in Energy Costs, 10-Year, Tennessee ............. 85
 

Table 11-4 Average Percentage Change in Energy-related Carbon Emissions, 10­

Year, Tennessee .......................................................................................... 86
 

Table 11-5 Average Percentage Change in Life-Cycle Costs, 10-Year, Tennessee........ 87
 

Table 11-6 Average Percentage Change in Energy Use from Adoption of Newer
 

Codes by City, Tennessee ........................................................................... 88
 

Table 11-7 Average Percentage Change in Energy Costs by City, 10-Year,
 

Tennessee .................................................................................................... 88
 

Table 11-8 Average Percentage Change in Carbon Emissions by City, Tennessee ........ 89
 

Table 11-9 Average Percentage Change in Life-Cycle Costs by City, 10-Year,
 

Tennessee .................................................................................................... 89
 

Table 11-10 Average Per Unit Change in Annual Energy Use, Tennessee..................... 90
 

Table 11-11 Statewide Change in Annual Energy Use for One Year of Construction,
 

Tennessee .................................................................................................... 91
 

Table 11-12 Average Per Unit Change in Energy Costs, 10-Year, Tennessee................ 92
 

Table 11-13 Statewide Change in Energy Costs for One Year of Construction,
 

10-Year, Tennessee ..................................................................................... 93
 

Table 11-14 Average Per Unit Change in Carbon Emissions, 10-Year, Tennessee ........ 93
 

Table 11-15 Statewide Change in Total Carbon Emissions for One Year of
 

Construction, 10-Year, Tennessee – Metric Tons ....................................... 94
 

Table 11-16 Average Per Unit Change in Life-Cycle Costs, 10-Year, Tennessee .......... 95
 

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Table 11-17 Statewide Change in Life-Cycle Costs for One Year of Construction, 

10-Year, Tennessee ..................................................................................... 96
 

Table 12-1 Average Annual Energy Use by Building Type and Energy Code,
 

Wisconsin .................................................................................................... 97
 

Table 12-2 Average Percentage Change in Energy Use from Adoption of Newer
 

Codes, 10-Year, Wisconsin ......................................................................... 98
 

Table 12-3 Average Percentage Change in Energy Use from Adoption of Newer
 

Codes by City, 10-Year, Wisconsin ............................................................ 99
 

Table 12-4 Average Per Unit Change in Annual Energy Use, Wisconsin .................... 100
 

Table 12-5 Statewide Change in Annual Energy Use for One Year of Construction,
 

Wisconsin .................................................................................................. 101
 

Table 12-6 Average Per Unit Change in Energy Costs, 10-Year, Wisconsin ............... 102
 

Table 12-7 Statewide Change in Energy Costs for One Year of Construction,
 

10-Year, Wisconsin ................................................................................... 102
 

Table 12-8 Average Per Unit Change in Carbon Emissions, 10-Year, Wisconsin........ 103
 

Table 12-9 Statewide Change in Total Carbon Emissions for One Year of
 

Construction, 10-Year, Wisconsin – Metric Tons..................................... 104
 

Table 12-10 Average Per Unit Change in Life-Cycle Costs, 10-Year, Wisconsin........ 104
 

Table 12-11 Statewide Change in Life-Cycle Costs for One Year of Construction,
 

10-Year, Wisconsin ................................................................................... 105
 

Table 13-1 Total Reductions by State for Adoption of the LEC Design, 10-Year........ 107
 

Table 13-2 Energy Use Reduction per Unit of Floor Area for Adoption of the LEC
 

Design by State, 10-Year .......................................................................... 108
 

Table 13-3 Energy Cost Reduction per kWh of Energy Use Reduction for Adoption
 

of the LEC Design by State, 10-Year ........................................................ 109
 

Table 13-4 Carbon Reduction per GWh of Energy Use Reduction for Adoption of
 

the LEC Design by State, 10-Year ............................................................ 109
 

Table 13-5 Life-Cycle Cost Reductions per Unit of New Floor Area for Adoption of
 

the LEC Design by State, 10-Year ............................................................ 110
 

Table 14-1 Average Percentage Change by State, 3-Story Office Building, 10-Year .. 112
 

Table 14-2 Nationwide Average Percentage Change in Energy Use by Building
 

Type ........................................................................................................... 115
 

Table 14-3 Nationwide Average Percentage Change in Energy Costs by Building
 

Type and Study Period Length .................................................................. 116
 

Table 14-4 Nationwide Average Percentage Change in Carbon Emissions by
 

Building Type............................................................................................ 116
 

Table 14-5 National Average Percentage Change in Life-Cycle Costs by Building
 

Type and Study Period Length .................................................................. 117
 

Table 14-6 Nationwide Average Percentage Change for LEC by Building Type,
 

10-Year ...................................................................................................... 119
 

Table 14-7 Average Percentage Change in Energy Use for LEC by Climate Zone
 

and State Energy Code .............................................................................. 120
 

Table 14-8 Average Percentage Change in Energy Costs for LEC by Climate Zone
 

and State Energy Code, 10-Year ............................................................... 121
 

Table 14-9 Average Change in Energy-related Carbon Emissions for LEC by
 

Climate Zone and State Energy Code ....................................................... 122
 

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Table 14-10 Average Percentage Change in Life-Cycle Costs for LEC by Climate 

Zone and Study Period .............................................................................. 123 

Table 15-1 Average Percentage Change by State, 3-Story Office Building, 10-Year .. 127 

Table 15-2 Nationwide Average Percentage Change in Energy Use by Building 

Type ........................................................................................................... 130 

Table 15-3 Nationwide Average Percentage Change in Energy Costs by Building 

Type and Study Period Length .................................................................. 130 

Table 15-4 Nationwide Average Percentage Change in Carbon Emissions by 

Building Type............................................................................................ 131 

Table 15-5 National Average Percentage Change in Life-Cycle Costs by Building 

Type and Study Period Length .................................................................. 131 

Table 15-6 Nationwide Percentage Change for ASHRAE 90.1-2007 by Building 

Type, 10-Year............................................................................................ 132 

Table 15-7 Average Percentage Change in Energy Use for ASHRAE 90.1-2007 by 

Climate Zone ............................................................................................. 133 

Table 15-8 Average Percentage Change in Energy Costs for ASHRAE 90.1-2007 by 

Climate Zone, 10-Year .............................................................................. 134 

Table 15-9 Average Change in Energy-related Carbon Emissions for ASHRAE 

90.1-2007 by Climate Zone....................................................................... 136 

Table 15-10 Average Percentage Change in Life-Cycle Costs for ASHRAE 

90.1-2007 by Climate Zone and Study Period .......................................... 137 

Table A-1 CBECS Categories and Subcategories .......................................................... 151 

Table A-2 New Commercial Building Construction Floor Area for 2003 through 

2007 by State and Building Type (S-I) ..................................................... 153 

Table A-3 New Commercial Building Construction Floor Area for 2003 through 

2007 by State and Building Type (I-P) ..................................................... 154 

Table A-4 New Commercial Building Construction Share by State and Building 

Type ........................................................................................................... 155 

Table A-5 CO2, CH4, and N2O Emissions Rates Electricity Generation by State ......... 156 

Table B-1 4-Story Apartment Building Summary Table for LEC and 10-Year Study 

Period ........................................................................................................ 157 

Table B-2 6-Story Apartment Building Summary Table for LEC and 10-Year Study 

Period ........................................................................................................ 158 

Table B-3 4-Story Dormitory Summary Table for LEC and 10-Year Study Period ..... 159 

Table B-4 6-Story Dormitory Summary Table for LEC and 10-Year Study Period ..... 160 

Table B-5 15-Story Hotel Building Summary Table for LEC and 10-Year Study 

Period ........................................................................................................ 161 

Table B-6 2-Story High School Summary Table for LEC and 10-Year Study Period 162 

Table B-7 8-Story Office Building Summary Table for LEC and 10-Year Study 

Period ........................................................................................................ 163 

Table B-8 16-Story Office Building Summary Table for LEC and 10-Year Study 

Period ........................................................................................................ 164 

Table B-9 1-Story Retail Store Summary Table for LEC and 10-Year Study Period . 165 

Table B-10 1-Story Restaurant Summary Table for LEC and 10-Year Study Period . 166 

Table B-11 4-Story Apartment Building Summary Table for ASHRAE 90.1-2007 

and 10-Year Study Period ......................................................................... 167
 

xxi
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table B-12 6-Story Apartment Building Summary Table for ASHRAE 90.1-2007
 

and 10-Year Study Period ......................................................................... 167
 

Table B-13 4-Story Dormitory Summary Table for ASHRAE 90.1-2007 and 10-Year
 

Table B-14 6-Story Dormitory Summary Table for ASHRAE 90.1-2007 and 10-Year
 

Table B-15 15-Story Hotel Building Summary Table for ASHRAE 90.1-2007 and
 

Table B-16 2-Story High School Summary Table for ASHRAE 90.1-2007 and
 

Table B-17 8-Story Office Building Summary Table for ASHRAE 90.1-2007 and
 

Table B-18 16-Story Office Building Summary Table for ASHRAE 90.1-2007 and
 

Table B-19 1-Story Retail Store Summary Table for ASHRAE 90.1-2007 and
 

Table B-20 1-Story Restaurant Summary Table for ASHRAE 90.1-2007 and
 

Study Period .............................................................................................. 167
 

Study Period .............................................................................................. 168
 

10-Year Study Period ................................................................................ 168
 

10-Year Study Period ................................................................................ 168
 

10-Year Study Period ................................................................................ 169
 

10-Year Study Period ................................................................................ 169
 

10-Year Study Period ................................................................................ 169
 

10-Year Study Period ................................................................................ 170
 

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List of Acronyms
 

Acronym Definition 

AEO Applied Economics Office 

AIRR Adjusted Internal Rate of Return 

ASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers 

BIRDS Building Industry Reporting and Design for Sustainability 

CBECS Commercial Building Energy Consumption Survey 

CH4 Methane 

CO2 Carbon Dioxide 

CO2e Carbon Dioxide Equivalent 

DOE Department of Energy 

EEFG EnergyPlus Example File Generator 

eGRID Emissions and Generation Resource Integrated Database 

EIA Energy Information Administration 

EL Engineering Laboaratory 

EPA Environmental Protection Agency 

FEMP Federal Energy Management Program 

FERC Federal Energy Regulatory Commission 

HVAC Heating, Ventilating, and Air Conditioning 

I-P Inch-Pounds (Customary Units) 

IECC International Energy Code Council 

ISO International Organization for Standardization 

LCA Life-Cycle Assessment 

LCC Life-Cycle Cost 

LEC Low Energy Case 

MRR Maintenance, Repair, and Replacement 

N2O Nitrous Oxide 

NERC North American Electric Reliability Corporation 

NIST National Institute of Standards and Technology 

PNNL Pacific Northwest National Laboratory 

ROI Return On Investment 

System International (Metric Units) 

SEER Seasonal Energy Efficiency Ratio 

SHGC Solar Heat Gain Coefficient 

xxiii
 

S-I 
 

 

Acronym De finition 

SPV Single Present Value 

UPV* Uniform Present Value Modified for Fuel Price Escalation 

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Executive Summary 

Executive Summary 

Energy efficiency requirements in current energy codes for commercial buildings vary 

across states, and many states have not yet adopted the newest energy standard editions. 

As of December 2011, state energy code adoptions range across all editions of the 

American Society of Heating, Refrigerating and Air-Conditioning Engineers Energy 

Standard for Buildings Except Low-Rise Residential Buildings (ASHRAE 

90.1-1999, -2001, -2004, and -2007). Some states in the U.S. do not have a code 

requirement for energy efficiency, leaving it up to the locality or jurisdiction to set its 

own requirement. There may be significant energy and cost savings to be realized by 

states if they were to adopt more energy efficient commercial building energy standard 

editions. 

The results of this report are based on analysis of the Building Industry Reporting and 

Design for Sustainability (BIRDS) database, which includes 12 540 whole-building 

energy simulation estimates covering 11 building types in 228 cities across all U.S. states 

for 9 study period lengths. The performance of buildings designed to meet current state 

energy codes is compared to their performance when meeting alternative building energy 

standard editions to determine whether more stringent energy standard editions are costeffective in reducing energy consumption and energy-related carbon emissions. Each 

state energy code is also compared to a “Low Energy Case” (LEC) building design that 

increases energy efficiency beyond the ASHRAE 90.1-2007 design. 

Results are analyzed in detail for the ASHRAE 90.1-2007 and LEC designs in both 

percentage and total value terms. The percentage savings results allow for direct 

comparisons across energy standard editions, building types, study period lengths, 

climate zones, and cities both within each state and across states and regions of the 

United States. Results are aggregated at the state level for seven states to estimate the 

magnitude of total energy use savings, energy cost savings, and cradle-to-grave energyrelated carbon emissions reductions that could be attained by adoption of a more energy 

efficient state energy code, and the life-cycle costs associated with those savings. The 

seven states chosen for this study to illustrate the detailed analysis possible with the 

BIRDS database are Alaska, Colorado, Florida, Maryland, Oregon, Tennessee, and 

Wisconsin. 

Overall, adoption of ASHRAE 90.1-2007 for the 19 states that have not yet adopted it as 

their state energy code leads to reductions in energy use, energy costs, and energy-related 

carbon emissions. The average state energy use reduction for new commercial buildings 

is 9.6 % while energy costs and carbon emissions realize average reductions of 12.2 % 

and 12.4 %, respectively for a 10-year study period. The reductions in energy use and 

carbon emissions are cost-effective, with average life-cycle costs decreasing by 0.7 %. 

xxv
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Executive Summary 

However, ASHRAE 90.1-2007 does not lead to energy efficiency improvements over 

older editions of ASHRAE 90.1 for all locations in the U.S. for two reasons. First, the 

simplification of the ASHRAE climate zones from 26 zones in ASHRAE 90.1-2001 to 8 

zones in ASHRAE 90.1-2004 resulted in the relaxation of some building envelope 

requirements for some locations. Second, ASHRAE 90.1-2007 has less stringent solar heat 

gain coefficient (SHGC) requirements relative to ASHRAE 90.1-2004 for some climate 

zones. As a result, high-rise, 100 % glazed buildings realize smaller reductions, and 

occasionally increases, in energy use because the less stringent window requirements 

overwhelm the stricter requirements for other energy efficiency measures analyzed in this 

study. 

Overall, adoption of the LEC design in all 50 states leads to nationwide reductions in 

energy use, energy costs, and carbon emissions greater than those realized by ASHRAE 

90.1-2007. The average state energy use reduction is 17.8 % over current state energy 

codes while energy costs and carbon emissions realize average reductions of 22.6 % and 

20.4 %, respectively. The reductions in energy use and carbon emissions are costeffective, with life-cycle costs decreasing by 1.1 % on average for a 10-year study period. 

States with current energy codes based on older editions of ASHRAE 90.1 realize greater 

reductions in energy use, energy costs, and carbon emissions for the ASHRAE 90.1-2007 

design. For a small office building, the 13 states with reductions in energy use of at least 

10 % have no state energy code or have adopted ASHRAE 90.1-1999/2001. For the LEC 

design, 14 of the 18 states that realize reductions in energy use greater than 25 % have no 

state energy code or have adopted ASHRAE 90.1-1999/2001, including all 13 states with 

reductions greater than 30 %. Similar trends hold for energy costs and energy-related 

carbon emissions. 

Over all building types, states located in the warmest climates realize the greatest 

reductions in energy use from adopting the “Low Energy Case” (LEC) design because 

several of the energy efficiency improvements (e.g., overhangs and daylighting controls) 

are more beneficial for warmer climates. However, states in colder climates see greater 

percentage reductions in energy costs and carbon emissions per percentage reduction in 

energy use because the energy efficiency measures tend to shift some energy use from 

electricity to natural gas consumption. Electricity is more expensive per unit of energy 

and typically has greater CO2e emissions factors per unit of energy relative to natural gas. 

Therefore the shift of energy consumption from electricity to natural gas can lead to 

greater reductions in energy costs and energy-related carbon emissions than reductions in 

total energy use. In an extreme case, cities located in Zone 8 realize a reduction in energy 

costs and carbon emissions while realizing an increase in total energy use. 

The results for the ASHRAE 90.1-2007 design have some similarities and some 

differences relative to the results for the LEC design. Similar to the LEC design, the 

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Executive Summary 

current state energy codes are a key driver of variation in the results. The variation across 

climate zones diverges depending on the state energy code. For locations in states that 

have not adopted any state energy code or have adopted older editions of ASHRAE 90.1 

(-1999 or -2001), warmer climate zones realize greater percentage reductions in energy 

use. For cities located in states that have adopted ASHRAE 90.1-2004, the percentage 

reductions in energy use do not follow the same trend. Instead the percentage changes are 

the greatest for cities in Zone 2 followed by Zone 7 and smallest for cities in Zone 1 and 

Zone 3. 

Similar to the LEC design, many cities realize a shift in energy use from electricity to 

natural gas, which decreases energy costs and carbon emissions by a greater percentage 

than the percentage decrease in energy consumption. However, nearly all zones realize 

smaller percentage reductions in carbon emissions than the percentage reductions in 

energy use because adopting ASHRAE 90.1-2007 decreases consumption of both 

electricity and natural gas for most cities. 

The length of the study period impacts life-cycle cost-effectiveness to some degree. 

Assuming nationwide adoption of the LEC design, a 10-year study period realizes 

average life-cycle cost decreases of 1.1 % for all building types and locations. The 

percentage decrease in life-cycle costs is 1.4 % for a 20-year, and 1.8 % for a 30-year, 

and 1.9 % for a 40-year study period. As the study period length increases from 5 to 40 

years, the life-cycle cost-effectiveness tends to increase for more energy efficient 

commercial building designs. This result is supported by the state-level aggregated 

impact estimates, with only one of the seven states in this study realizing an increase in 

total life-cycle costs from the adoption of the LEC design. 

States with the most newly constructed commercial building floor area realize the 

greatest total energy use, energy cost, and energy-related carbon emissions reductions 

from adopting ASHRAE 90.1-2007 or the LEC design even if those states do not realize 

the greatest percentage reductions. Maryland and Oregon, both of which have adopted 

ASHRAE 90.1-2007, realize reductions in energy use of 15 % for the LEC design. 

However, Maryland realizes total reductions in energy use of 622 GWh while Oregon 

realizes reductions of 261 GWh because Maryland has almost twice the amount of newly 

constructed floor area. Similarly, Florida, which ranks 1st in the country for new floor 

area, realizes greater aggregate reductions in energy costs and energy-related carbon 

emissions reductions than Maryland even though both states realize approximately the 

same percentage reductions in these two metrics. 

In general, the states that realize the greatest reductions in energy use also realize the 

greatest reductions in energy costs and energy-related carbon emissions. However, states 

with higher electricity and natural gas rates will realize greater reductions in energy costs. 

For example, Tennessee realizes greater aggregate reductions in energy use than 

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Executive Summary 

Maryland (808 GWh versus 622 GWh), but less total energy cost savings ($58.7 million 

versus $62.4 million). Also, states that rely heavily on coal-fired electricity will realize 

greater emissions reductions per unit of energy reduced than those states using more 

alternative energy sources. For example, Colorado relies on coal for 72 % of electricity 

generation and decreases carbon emissions by over 1000 tons per GWh of electricity 

generation. Meanwhile, Oregon relies on coal for 7 % of electricity generation and only 

saves 560 tons per GWh. 

For a 10-year study period, adopting either ASHRAE 90.1-2007 or the LEC design 

reduces total life-cycle costs for the three states in this study that have adopted an older 

edition of ASHRAE 90.1 or have not yet adopted a state energy code for commercial 

buildings: $815 858 for Alaska, $32.5 million for Colorado, and $4.4 million for 

Tennessee. Meanwhile, adopting the LEC design would decrease life-cycle costs for six 

of the seven states selected for this study, ranging from $2.3 million to $151.3 million. 

The variation is primarily driven by the amount of new construction in a state. The lifecycle cost savings realized by these six states makes the increase in life-cycle costs 

realized by Oregon insignificant. 

This study is limited in scope and would be strengthened by including sensitivity 

analysis, expanding the BIRDS database, and enabling public access to all the results. 

Detailed analysis of the remaining 43 states would make possible an estimate of the 

nationwide impact of adopting more stringent building energy codes. Expansion of the 

environmental assessment beyond energy-related carbon emissions to include both a full 

range of life-cycle environmental impacts and building activities, such as construction, 

maintenance, repair, and replacement would enable comprehensive sustainability 

assessment. Additional energy efficiency measures, fuel types, discount rates, and 

building types would also expand the scope of the database. Also, given that new 

buildings account for a small fraction of the entire building stock, incorporating analysis 

of retrofitting these same prototype buildings would greatly increase the scope of the 

database. The extensive BIRDS database can be used to answer many more questions 

than posed in this report, and should be made available to the public through a simple-touse software tool that allows other researchers access to the database for their own 

research on building energy efficiency. These improvements are underway, with more 

detailed reporting and release of the BIRDS software scheduled for 2013. 

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Introduction
 

1	 Introduction 

1.1 Background and Purpose 

Energy efficiency requirements in current energy codes for commercial buildings vary 

across states, and many states have not yet adopted the newest energy standard editions. 

As of December 2011, state energy code adoptions range across all editions of the 

American Society of Heating, Refrigerating and Air-Conditioning Engineers Energy 

Standard for Buildings Except Low-Rise Residential Buildings (ASHRAE 

90.1-1999, -2001, -2004, and -2007). Some states do not have a code requirement for 

energy efficiency, leaving it up to the locality or jurisdiction to set its own requirement. 

There may be significant energy and cost savings to be realized by states if they were to 

adopt more energy efficient commercial building energy standard editions. 

The purpose of this study is to estimate the impacts that the adoption of more stringent 

energy codes for commercial buildings would have on building energy use, operational 

energy costs, energy-related carbon emissions, and building life-cycle costs. The results 

are analyzed for selected states and across all states to answer the following questions: 

•	 State-By-State Analysis 

o	 How much, on a percentage basis, does each more stringent standard decrease 

building energy consumption, energy costs, and energy-related carbon 

emissions relative to the state’s current energy code? 

o	 Is adopting a more stringent energy standard life-cycle cost-effective? 

o	 What causes variation across cities within a state for building energy 

consumption, energy costs, energy-related carbon emissions, and life-cycle 

costs reduction? Do these vary across states? 

o	 Based on new construction in each state, how much can a state save in total 

energy consumption, energy costs, energy-related carbon emissions, and lifecycle costs over time? 

•	 Across-State Analysis 

o	 Are newer energy standard editions really more energy efficient? And if so, 

how much more efficient? 

o	 Which states would benefit the most from adopting newer energy standard 

editions? 

o	 What factors drive the relative energy savings across states? 

o	 How does the study period length impact the cost-effectiveness of energy 

efficiency investments? 

Seven states that represent the full range of state energy codes are chosen for the detailed 

state-by-state analysis. The average changes in energy use, energy costs, energy-related 

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Introduction
 

carbon emissions, and life-cycle costs for all states are used for cross-state comparative 

analysis. 

1.2 Literature Review 

Pacific Northwest National Laboratory (2009) estimates the impacts for each state of 

adopting the most recent edition of the ASHRAE 90.1 Standard as of 2009, ASHRAE 

90.1-2007, as the commercial building energy code relative to the state’s current energy 

code. For states without a state commercial building energy code, the baseline is 

assumed to be ASHRAE 90.1-1999 because it is considered to represent common practice 

in the industry. The annual energy use savings and energy cost savings are estimated for 

three Department of Energy (DOE) benchmark buildings -- a medium-sized office 

building, a non-refrigerated warehouse, and a mid-rise apartment building -- to represent 

non-residential, semi-heated, and residential uses, respectively. The buildings are 

simulated in the EnergyPlus whole building energy software for 97 cities located across 

the U.S., ensuring that each climate zone in each state is represented. The study reports 

annual electricity and natural gas consumption per square foot of floor area for the 

buildings, assuming they are built to meet both the state’s current code and ASHRAE 

90.1-2007. Based on these results, the percentage savings in energy and energy costs are 

calculated for the three building types for each state. The study does not compare energy 

use and energy costs across states. Life-cycle costs and carbon emissions are not 

considered in the study. 

Kneifel (2010) creates the framework to simultaneously analyze the impacts of 

improving energy efficiency on energy use, energy costs, life-cycle costs, and carbon 

emissions through an integrated design context for new commercial buildings. The paper 

compares the savings of constructing 11 prototype commercial buildings to meet the 

building envelope requirements of ASHRAE 90.1-2007 and a “Low Energy Case,” 

relative to ASHRAE 90.1-2004, for 16 cities in different climate zones across the 

contiguous United States. The paper finds minimal improvements in energy efficiency 

from building to meet ASHRAE 90.1-2007 relative to ASHRAE 90.1-2004 while 

significant savings is found by building to meet the “Low Energy Case.” The “Low 

Energy Case” is often cost-effective on a first cost basis and is always cost-effective over 

the longer study period lengths. 

Kneifel (2011a) expands on the framework and analysis in Kneifel (2010) by analyzing 

the impact of adopting the building envelope requirements of ASHRAE 90.1-2007 and a 

“Low Energy Case” relative to ASHRAE 90.1-2004 in terms of energy use, energy costs, 

energy-related carbon emissions, and life-cycle costs reduction for 228 cities across the 

U.S. with at least one city in every climate zone in each state. Analysis includes 4 study 

period lengths: 1, 10, 25, and 40 years. The paper finds that, on average, the more energy 

efficient building designs are cost-effective. However, there is significant variation across 

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Introduction 

states in terms of energy savings and life-cycle cost-effectiveness driven by both climate 

and construction costs. There is also significant variation across cities within a state, even 

cities located within the same climate zone. These variations are a result of differences in 

local material and labor costs as well as energy costs. 

1.3 Approach 

This study uses the Building Industry Reporting and Design for Sustainability (BIRDS) 

database to analyze the benefits and costs of increasing building energy efficiency across 

the United States. BIRDS is a compilation of whole building energy simulations, building 

construction cost data, maintenance, repair, and replacement rates and costs, and energyrelated carbon emissions data for 11 building types in 228 cities across all U.S. states. 

The analysis compares energy performance of buildings designed to each state’s current 

energy code for commercial buildings to the performance of more energy efficient 

building designs to determine the energy use savings, energy cost savings, and energyrelated carbon emissions reductions, and the associated life-cycle costs, resulting from 

adopting stricter standards as the state’s energy code. 

Results are analyzed both in percentage and total value terms. The percentage savings 

results allow for direct comparisons across energy standard editions, building types, study 

period lengths, climate zones, and cities both within each state and across states and 

regions of the United States. Results are aggregated to the state level to estimate the 

magnitude of total energy use savings, energy cost savings, and energy-related carbon 

emissions reductions that could be attained by adoption of a more stringent state energy 

code, and the associated total life-cycle costs. 

Results are summarized through both tables and figures. In cases where the material 

being discussed is of secondary importance, the associated table or figure is placed in the 

Appendices. The order in which tables and figures appear in the Appendices corresponds 

to the order in which they are cited in the text. 

3
 
Introduction
 

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Study Design 

2 Study Design 

The BIRDS database used in this study was built following the framework developed in 

Kneifel (2010) and further expanded in Kneifel (2011a).This study analyzes whole 

building energy simulations, life-cycle costs, and life-cycle carbon emissions for 12 540 

buildings covering 5 energy efficiency designs for 11 new commercial building types, 

228 cities across the United States, and 9 study period lengths.1 

2.1 Building Types 

The building characteristics in Table 2-1 describe the 11 building types used in this study, 

which include 2 dormitories, 2 apartment buildings, a hotel, 3 office buildings, a school, a 

retail store, and a restaurant. These building types represent 46 % of the existing U.S. 

commercial building stock floor space.2 The prototype buildings range in size from 465 

m 2 (5000 ft2

) to 41 806 m2 (450 000 ft2). The building abbreviations defined in Table 2-1 

are used to represent the building types in tables throughout this study. 

Table 2-1 Building Characteristics 

Building Type Bldg. Abbr. Floors 

Floor 

Height 

m (ft) 

Wall Roof† Pct. 

Glazing 

Building Size 

m 2 (ft2

) 

Occupancy 

Type 

U.S. Floor 

Space (%) 

Dormitory DORMI04 4 3.66 (12) Mass IEAD 20 % 3097 (33 333) Lodging 7.1 % 

Dormitory DORMI06 6 3.66 (12) Steel IEAD 20 % 7897 (85 000) 

Hotel HOTEL15 15 3.05 (10) Steel IEAD 100 % 41 806 (450 000) 

Apartment APART04 4 3.05 (10) Mass IEAD 12 % 2787 (30 000) 

Apartment APART06 6 3.15 (10) Steel IEAD 14 % 5574 (60 000) 

School, High HIGHS02 2 4.57 (15) Mass IEAD 25 % 12 077 (130 000) Education 13.8 % 

Office OFFIC03 3 3.66 (12) Mass IEAD 20 % 1858 (20 000) Office 17.0 % 

Office OFFIC08 8 3.66 (12) Mass IEAD 20 % 7432 (80 000) 

Office OFFIC16 16 3.05 (10) Steel IEAD 100 % 24 155 (260 000) 

Retail Store RETAIL1 1 4.27 (14) Mass IEAD 10 % 743 (8000) Mercantile* 6.0 % 

Restaurant RSTRNT1 1 3.66 (12) Wood IEAD 30 % 465 (5000) Food Service 2.3 % 

*Only includes non-mall floor area. 

†IEAD = Insulation Entirely Above Deck 

2.2 Building Designs 

Current state energy codes are based on different editions of the International Energy 

Conservation Code (IECC) or ASHRAE 90.1 Standard, which have requirements that 

vary based on a building’s characteristics and the climate zone of the location. For this 

study, the ASHRAE 90.1 Standard-equivalent design is used to meet current state energy 

1 See Kneifel (2011b) for additional details on the whole building energy simulations used in the BIRDS 

database. 

2 Based on the Commercial Building Energy Consumption Survey (CBECS) database 

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Study Design 

codes and to define the alternative building designs. Additionally, a “Low Energy Case” 

design that goes beyond ASHRAE 90.1-2007 requirements is included as a building 

design alternative, and for simplicity may be referred to as an “edition” of the energy 

standard throughout the remainder of this report. 

Table 2-2 shows that commercial building energy codes as of December 2011 vary by 

state.3 In a few instances, local jurisdictions have adopted energy standard editions that 

are more stringent than the state energy codes.4 These cities are also included in Table 

2-2. 

Table 2-2 Energy Code by State and City Exception 

Location Energy Code Location Energy Code Location Energy Code 

AK None IN 2007 NV 2004 

AL None KS None NY 2007 

Huntsville 2001 KY 2007 OH 2007 

AR 2001 LA 2007 OK None 

AZ None MA 2007 OR 2007 

Flagstaff 2004 MD 2007 PA 2007 

Phoenix 2004 ME None RI 2007 

Tucson 2004 MI 2007 SC 2004 

CA 2007 MN 2004 SD None 

CO 2001 MO None Huron 2001 

Grand Junction 2004 St Louis 2001 TN 2004 

CT 2007 MS None TX 2007 

DE 2007 MT 2007 UT 2007 

FL 2007 NC 2007 VA 2007 

GA 2007 ND None VT 2007 

HI 2004 NE 2007 WA 2007 

IA 2007 NH 2007 WI 2007 

ID 2007 NJ 2007 WV 2001 

IL 2007 NM 2007 WY None 

Note: Some city ordinances require energy codes that exceed state energy codes. 

Note: State codes as of December 1, 2011. 

State energy codes vary from ASHRAE 90.1-1999 to ASHRAE 90.1-2007 with some 

regional trends shown in Figure 2-1. The states in the central U.S. tend to wait longer to 

adopt newer ASHRAE 90.1 Standard editions. However, there are many cases in which 

energy codes of neighboring states vary drastically. For example, Missouri has no state 

energy code while of the 8 surrounding states, 2 have no state energy code, 1 has adopted 

3 Since the publication of Kneifel (2011b) and Kneifel (2012), the BIRDS database has been updated to 

include subsequent changes in state energy codes through December 2011. 

4 Local and jurisdictional requirements are obtained from the Database of State Incentives for Renewables 

and Efficiency (DSIRE). State energy code requirements targeting only public buildings and green 

standards are ignored in this study. 

6
 
 

 

 

 

 

 

 

 

 

 

 

Study Design 

ASHRAE 90.1-2001, 1 has adopted ASHRAE 90.1-2004, and 4 have adopted ASHRAE 

90.1-2007. 

Figure 2-1 State Commercial Energy Codes5 

The 228 cities and ASHRAE climate zones for the U.S. are seen in Figure 2-2. These 

cities are selected for three reasons. First, the cities are spread out to represent the entire 

United States, and represent as many climate zones in each state as possible. Second, the 

locations include all the major population centers in the country. Third, multiple locations 

for a climate zone within a state are included to allow building costs to vary for each 

building design. 

5 Figure was obtained from the DOE Building Technologies Program in December 2011. 

7
 
 

 

 

 

 

 

 

 

 

 

 

 

 

Study Design 

Figure 2-2 Cities and ASHRAE Climate Zones 

2.3 Study Period Lengths 

Nine study period lengths are chosen for this analysis: 1 year, 5 years, 10 years, 15 years, 

20 years, 25 years, 30 years, 35 years, and 40 years. The wide cross section of potential 

investment time horizons allows this report to analyze the impact the study period length 

has on the benefits and costs of more stringent state energy code adoption. A 1-year study 

period is representative of a developer that intends to sell a property soon after it is 

constructed. A 5-year to 15-year study period best represents a building owner’s time 

horizon because few owners are concerned about costs realized beyond a decade into the 

future. The 20-year to 40-year study periods better represents institutions, such as 

colleges or government agencies, because these entities will own or lease buildings for 20 

or more years. The 10-year study period length is the focus of this study. 

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Cost Data 

3 Cost Data 

The cost data collected to estimate life-cycle costs originates from multiple sources, 

including RSMeans databases, Whitestone (2008), and the U.S. Energy Information 

Administration (EIA). Costs are grouped into two categories, first costs that include 

initial building construction costs and future costs that include operational costs, 

maintenance, repair, and replacement costs, and building residual value. Both of these 

cost categories are described below. 6 

3.1 First Costs 

Building construction costs are obtained from the RS Means CostWorks online databases. 

The costs of a prototypical building are estimated by the RS Means CostWorks Square 

Foot Estimator to obtain the default costs for each building type for each component. The 

RS Means default building is the baseline used to create a building that is compliant with 

each of the five energy efficiency design alternatives: ASHRAE 90.1-1999, ASHRAE 

90.1-2001, ASHRAE 90.1-2004, ASHRAE 90.1-2007, and the higher efficiency “Low 

Energy Case" (LEC) design. The RS Means default buildings are adapted to match the 

five prototype building designs by using the RS Means CostWorks Cost Books databases. 

Five components -- roof insulation, wall insulation, windows, lighting, and HVAC 

efficiency -- are changed to make the prototypical designs ASHRAE 

90.1-1999, -2001, -2004, and -2007 compliant. A summary of the minimum requirement 

ranges, excluding HVAC efficiency, for each building design are shown in Table 3-1. 

The windows are selected to meet the minimum window characteristics (U-factor, solar 

heat gain coefficient (SHGC), and visible transmittance (VT)) required by the building 

design at the lowest possible cost. The lighting density in watts per unit of conditioned 

floor area is adjusted to meet each standard edition’s requirements. 

6 See Kneifel (2012) for additional details of the cost data used in the BIRDS database. 

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Cost Data 

Table 3-1 Energy Efficiency Component Requirements for Alternative Building 

Designs 

Design ASHRAE ASHRAE ASHRAE ASHRAE Low Energy 

Component Parameter Units 90.1-1999 90.1-2001 90.1-2004 90.1-2007 Case* 

Roof 

Insulation R-Value m 2

∙K/W 

(ft2

∙°F∙h/Btu) 

1.7-4.4 

(10.0-25.0) 

1.7-4.4 

(10.0-25.0) 

2.6-3.5 

(15.0-20.0) 

2.6-3.5 

(15.0-20.0) 

4.4-6.2 

(25.0-35.0) 

Wall 

Insulation R-Value m 2

*K/W 

(ft2

∙°F∙h/Btu) 

0.0-3.8 

(0.0-21.6) 

0.0-3.8 

(0.0-21.6) 

0.0-2.7 

(0.0-15.2) 

0.0-2.7 

(0.0-15.2) 

0.7-5.5 

(3.8-31.3) 

Windows U-Factor W/(m2∙K) 

(Btu/(h∙ft2

∙°F)) 

1.42-7.21 

(0.25-1.27) 

1.42-7.21 

(0.25-1.27) 

1.99-6.47 

(0.35-1.14) 

2.50-6.47 

(0.44-1.14) 

1.97-6.42 

(0.35-1.13) 

SHGC Fraction 0.14-NR† 0.14-NR† 0.17-NR† 0.25-NR 0.25-0.47 

Lighting Power 

Density W/m2 (W/ft2

) 14.0-20.5 

(1.3-1.9) 

14.0-20.5 

(1.3-1.9) 

10.8-16.1 

(1.0-1.5) 

10.8-16.1 

(1.0-1.5) 

8.6-16.1 

(0.8-1.5) 

Overhangs None None None None Zones 1-5 

Daylighting None None None None Zones 1-8 

†North facing SHGC requirements are less restrictive than the requirements for the other 3 orientations. 

* Low Energy Case design requirements are taken from the EnergyPlus simulations. 

NR = No Requirement for one or more climate zones. By definition, the value of SHGC cannot exceed 1.0. 

The LEC design increases the thermal efficiency of insulation and windows beyond 

ASHRAE 90.1-2007, further reduces the lighting power density, and adds daylighting and 

window overhangs. The lighting density of the lighting system is decreased by first 

increasing the efficiency of the lighting system and then decreasing the number of 

fixtures in the lighting system.7 Daylighting is included for all building types and climate 

zones. Overhangs are placed on the east, west, and south sides of the building for each 

floor in Climate Zone 1 through Climate Zone 5 because these warmer climates are the 

zones that benefit from blocking solar radiation.8 

Table 3-2 summarizes the HVAC efficiency requirements for each building design option 

across the different types of HVAC equipment.9 Note that the LEC design assumes the 

same efficiency as ASHRAE 90.1-2007. This study assumes that cooling equipment is run 

on electricity while heating equipment is run on natural gas. The most significant 

increases in HVAC efficiency requirements occur between ASHRAE 90.1-1999 and 

ASHRAE 90.1-2001 except for rooftop packaged units, which have consistently 

increasing requirements across multiple ASHRAE 90.1 Standard editions. 

7 First, incandescent lighting is replaced with compact fluorescent lighting while typical T-12 fluorescent 

tube lighting is replaced with more efficient T-8 fluorescent tube lighting to decrease the lighting density of 

the lighting system. Second, the number of fixtures is reduced to meet the remainder of the required 

reduction in watts per unit of floor area. Increasing the efficiency of the lighting increases the costs of 

construction. The first approach increases first costs while the second approach decreases first costs for the 

lighting system. This approach is based on Belzer et al. (2005) and Halverson et al. (2006). 

8 Overhang cost source is Winiarski et al. (2003) 

9 This study does not account for new HVAC efficiency requirements set by federal regulations. 

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Cost Data 

Table 3-2 HVAC Energy Efficiency Requirements for Alternative Building Designs
 

HVAC Equipment Type Unit ASHRAE ASHRAE ASHRAE ASHRAE Low Energy 

Type 90.1-1999 90.1-2001 90.1-2004 90.1-2007 Case 

Cooling Rooftop Packaged Unit EER 8.2-9.0 9.0-9.9 9.2-10.1 9.5-13.0 9.5-13.0 

Air-Cooled Chiller COP 2.5-2.7 2.8 2.8 2.8 2.8 

Water-Cooled Chiller COP 3.80-5.20 4.45-5.50 4.45-5.50 4.45-5.50 4.45-5.50 

Split System with EER 8.7-9.9 9.9-10.1 10.1 10.1 10.1 

Condensing Unit 

Heating Hot Water Boiler Et 75 % to 80 % 75 % to 80 % 75 % to 80 % 75 % to 80 % 75 % to 80 % 

Furnace Et 80 % 75 % to 80 % 75 % to 80 % 75 % to 80 % 75 % to 80 % 

Assume that Ec = 75% Et and AFUE = Et, where Ec = combustion efficiency; Et = thermal efficiency; AFUE = Annual Fuel 

Utilization Efficiency 

EER = Energy Efficiency Ratio 

COP = Coefficient of Performance 

Note: Efficiency requirement ranges are based on the system sizes calculated in the whole building energy simulations. 

The HVAC system size varies across the five building designs because changing the 

thermal characteristics of the building envelope alters the heating and cooling loads of the 

building. The EnergyPlus whole building energy simulations “autosize” the HVAC 

system to determine the appropriate system size to efficiently maintain the thermal 

comfort and ventilation requirements. For each building design, the HVAC cost for the 

default HVAC system is replaced with the cost of the “autosized” HVAC system. An 

HVAC efficiency cost multiplier is used to adjust the HVAC costs in accordance with the 

standard efficiency requirements shown in Table 3-2. 

Construction costs for a building in each location are estimated by summing the baseline 

costs for the RS Means default building and the changes in costs required to meet the 

alternative prototype designs. National average construction costs are adjusted with the 

2009 RS Means CostWorks City Indexes to control for local material and labor price 

variations. The “weighted average” city construction cost index is used to adjust the costs 

for the baseline default building while “component” city indexes are used to adjust the 

costs for the design changes. Once the indexed construction cost of the building is 

calculated, it is multiplied by the contractor “mark-up” rate, 25 %, and architectural fees 

rate, 7 %, to estimate the building's “first costs” of construction for the prototype 

buildings. These rates are the default values used by the RSMeans Square Foot 

Estimator. 

3.2 Future Costs 

Component and building lifetimes and component repair requirements are based on data 

from Whitestone (2008). Building service lifetimes are assumed constant across climate 

zones: apartment buildings last for 65 years; dormitories for 44 years; and hotels, schools, 

office buildings, retail stores, and restaurants for 41 years. 

11
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cost Data 

Building component maintenance, repair, and replacement (MRR) rates are from Kneifel 

(2010) and Kneifel (2011a). Insulation and windows are assumed to have a lifespan 

greater than 40 years and have no maintenance requirements. Insulation is assumed to 

have no repair costs. Windows have an assumed annual repair cost equal to replacing 1 % 

of all window panes, with costs that vary depending on the required window 

specifications. The heating and cooling units have different lifespans and repair rates 

based on climate, ranging from 4 to 33 years for repairs and 13 to 50 years for 

replacements. 

Maintenance, repair, and replacement cost data are collected from two sources. The total 

maintenance and repair costs per square foot of conditioned floor area (minus the HVAC 

maintenance and repair costs) represent the baseline MRR costs per unit of floor area, 

which occur for a building type regardless of the energy efficiency measures incorporated 

into the design. These data are collected from Whitestone (2008), which reports average 

maintenance and repair costs per unit of floor area by building component for each year 

of service life for each building type. The building types in Whitestone do not match 

exactly to the 11 building types selected for this study, and the most comparable profile is 

selected. 

RS Means CostWorks is the source of MRR costs for the individual components for 

which MRR costs change across alternative building designs, which in this analysis are 

the HVAC system, lighting system, and windows. Lighting systems, including 

daylighting controls for the LEC design, are assumed to be replaced every 20 years. The 

HVAC system size varies based on the thermal performance of the alternative building 

design, which results in varying MRR costs because smaller systems are relatively 

cheaper to maintain, repair, and replace. 

Future MRR costs are discounted to equivalent present values using the Single Present 

Value (SPV) factors for future non-fuel costs reported in Rushing and Lippiatt (2008), 

which are calculated using the U.S. Department of Energy's 2008 real discount rate for 

energy conservation projects (3 %). 

A building's residual value is its value at the end of the study period. It is estimated in 

three parts, for the building (excluding components replaced during the study period), the 

HVAC system, and the lighting system based on the approach defined in Fuller et al. 

(1996). The building's residual value is assumed to be equal to the building's first cost 

(minus any components replaced over the study period) multiplied by the ratio of the 

study period to the service life of the building, and discounted from the end of the study 

period. 

Two components may be replaced during the study period, the lighting and HVAC 

systems. Residual values for these components are computed for each location in a 

12
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Cost Data 

similar manner to the building residual value. The remaining “life” of the component is 

determined by taking its service life minus the number of years since its last installation, 

whether it occurred during building construction or replacement. The ratio of remaining 

life to service life is multiplied by the installed cost of the lighting and HVAC systems, 

and discounted from the end of the study period. The lighting system service life is 20 

years while the HVAC system service life varies by location based on Towers et al 

(2008). 

Annual energy costs are estimated by multiplying annual electricity and natural gas use 

predicted by the whole building energy simulation by the average state retail commercial 

electricity and natural gas prices, respectively. Average state commercial electricity and 

natural gas prices for 2009 are collected from the Energy Information Administration 

(EIA) Electric Power Annual State Data Tables and Natural Gas Navigator, respectively. 

The electricity and natural gas prices are assumed to change over time according to EIA 

forecasts from 2009 to 2039. These forecasts are embodied in the Federal Energy 

Management Program (FEMP) Uniform Present Value Discount Factors for energy price 

estimates (UPV*) reported in Rushing and Lippiatt (2009).10 The UPV* values are used 

to discount future energy costs to equivalent present values. The discount factors vary by 

Census region, building sector, and fuel type. 

10 The escalation rates for years 31-40 are assumed to be the same as for year 30. 

13
 
Cost Data 

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Building Stock Data 

4 Building Stock Data 

Aggregating the savings for individual newly constructed commercial buildings to the 

state level requires new construction data for each building type within each state. This 

study uses the commercial building weighting factors reported in Jarnagin and 

Bandyopadhyay (2010) to estimate the total energy use savings, energy cost savings, lifecycle cost savings, and carbon emissions reduction resulting from adopting newer energy 

standard editions for each state. Jarnagin and Bandyopadhyay (2010) use two databases 

to generate the commercial building weighting factors: the Commercial Buildings Energy 

Consumption Survey (CBECS) and a McGraw-Hill construction dataset. The databases 

and the resulting weighting factors are described below. 

4.1 Databases 

The Commercial Buildings Energy Consumption Survey (CBECS) is a sample survey 

that collects information on the existing stock of U.S. commercial buildings. The sample 

includes 5215 buildings across the U.S. and 14 building type categories: education, food 

sales, food service, health care, lodging, mercantile, office, public assembly, public order 

and safety, religious worship, service, warehouse and storage, other, and vacant. Each 

category includes up to 12 subcategories as shown in Table A-1 in Appendix A. The 

survey data do not report the age or specific location of the building to protect the 

confidentiality of the respondents. 

The McGraw-Hill dataset includes data for all new commercial buildings and additions, 

over 254 000 records and 761.8 million m2 (8.2 billion ft2

) of new construction, for 2003 

through 2007. The data are more detailed than the CBECS data, and includes year of 

construction and location. 

4.2 Weighting Factors 

Jarnagin and Bandyopadhyay (2010) maps the more detailed McGraw-Hill dataset to the 

CBECS categories and subcategories shown in Table 4-1. The prototype commercial 

buildings analyzed in this study, shown in bold, represent 46.4 % of nationwide new 

commercial building stock square footage for 2003 through 2007. The McGraw-Hill 

dataset is aggregated at the CBECS category-level. For this study, a prototype building is 

assumed to represent its entire CBECS category, which implies the prototypes together 

represent 56.8 % of the new commercial building stock. 

15
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Building Stock Data 

Table 4-1 New Commercial Building Construction (U.S., 2003 through 2007) 

Category Subcategory 

Conditioned Floor 

Area 

1000 m2 (1000 ft2

) 

Percentage 

in Category 

Percentage 

of Total 

Office Large 20 451 (220 134) 22.2 % 2.6 % 

Office Medium 37 170 (400 091) 40.4 % 4.8 % 

Office Small 34 468 (371 009) 37.4 % 4.5 % 

Retail 93 762 (1 009 246) 12.2 % 

Strip Mall 34 847 (375 093) 4.5 % 

School Primary 30 697 (330 418) 4.0 % 

School Secondary 63 686 (685 508) 8.3 % 

Hospital 21 194 (228 131) 2.8 % 

Other Health Care 26 865 (289 171) 3.5 % 

Restaurant Sit Down 4055 (43 650) 0.5 % 

Restaurant Fast Food 3605 (38 809) 0.5 % 

Hotel Large 30 432 (327 562) 0.4 % 

Hotel/Motel Small 10 576 (113 837) 1.4 % 

Warehouse 102 746 (1 105 951) 13.4 % 

Apartment High-rise 55 114 (593 241) 55.1 % 7.2 % 

Apartment Mid-rise 44 997 (484 343) 44.9 % 5.9 % 

No Prototype 153 270 (1 649 785) 20.0 % 

Total (2003 to 2007) 767 934 (8 265 977) 100.0 % 

The types and floor area of buildings being constructed vary across states. Table A-2, 

Table A-3, and Table A-4 in Appendix A report new building construction for 2003 

through 2007 by building type and state, in total square meters, total square feet, and 

percentage terms, respectively. The data in Table A-2 are used to aggregate the total 

savings for the new construction in the CBECS categories represented by the prototype 

building analyzed in this study. Nine of the eleven prototype commercial buildings 

analyzed in this study are covered by data reported in Table 4-1. No data for dormitories 

are reported, which limites the ability to estimate statewide impacts for the two types of 

dormitories. 

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Analysis Approach 

5 Analysis Approach 

The analysis in this report compares benefits and costs of the status quo state energy 

codes to more stringent alternatives. The relative changes in energy use, energy costs, 

energy-related carbon emissions, and life-cycle costs use the current energy code for a 

state as the baseline and uses each ASHRAE 90.1 Standard edition that is newer than the 

standard required by the current state energy code as an alternative design. The results are 

considered on both a percentage change and an aggregate change basis. 

5.1 Energy Use 

The analysis uses each state’s current energy code as the baseline energy efficiency 

design. For any state without a state energy code, ASHRAE 90.1-1999 is assumed to be 

the baseline because it represents minimum energy-related industry practices. The 

baseline for each state is compared to the higher energy efficiency building designs to 

determine the relative annual energy savings resulting from adopting the alternative 

standard edition as the state’s energy code. For example, if a state’s energy code has 

adopted ASHRAE 90.1-2001 as its energy standard requirement, this baseline energy use 

is compared to the energy use of all newer energy standard editions, ASHRAE 90.1-2004 

and ASHRAE 90.1-2007, as well as a “Low Energy Case” that increases building energy 

efficiency beyond ASHRAE 90.1-2007. 

It is assumed that the building maintains its energy efficiency performance throughout the 

study period, resulting in energy consumption remaining constant over the entire study 

period. This assumption is reasonable given the maintenance, repair, and replacement 

costs included in the analysis to ensure the building and its equipment perform as 

expected. 

5.2 Life-Cycle Costing 

Life-cycle costing (LCC) takes into account all relevant costs throughout the chosen 

study period, including construction costs, maintenance, repair, and replacement costs, 

energy costs, and residual values. A cost’s present value (PV) is calculated by 

discounting its nominal value into today’s dollars based on the year the cost occurs and 

the assumed discount rate. LCC of buildings typically compares the costs for a baseline 

building design to the costs for alternative, more energy-efficient building designs to 

determine if future operational savings justify higher initial investments.11 For this study, 

the design based on any ASHRAE 90.1 Standard edition that is newer than the standard 

edition required by the current state energy code is compared to the baseline state energy 

code compliant design to determine the changes in life-cycle costs. 

11 All life-cycle cost calculations are based on ASTM Standards of Building Economics (2012). 

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Analysis Approach 

Two metrics are used to analyze changes in life-cycle costs: net LCC savings and net 

LCC savings as a percentage of base case LCC. Net LCC savings is the difference 

between the base case and alternative design's LCCs. 

5.3 Carbon Assessment 

The BIRDS database expands on Kneifel (2011a) by conducting a life-cycle assessment 

(LCA) of energy-related greenhouse gas emissions, following guidance in the 

International Organization for Standardization (ISO) 14040 series of standards for LCA. 

The analysis quantifies the greenhouse gas emissions from electricity and natural gas use 

on a cradle-to-grave basis, including emissions from raw materials acquisition, materials 

processing, generation, transmission, distribution, use, and end-of-life. 

The assessment of cradle-to-grave energy-related carbon emissions considers a number of 

greenhouse gases for two types of energy consumption, electricity and natural gas. 

Carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) are the most prevalent. 

While carbon emissions from natural gas use can be assessed on a national average basis, 

those from electricity use are highly dependent upon the fuel mixes of regional electricity 

grids. For this reason, electricity emissions are assessed at the state-level using North 

American Electric Reliability Corporation (NERC) sub-region level data.12 The life-cycle 

data sets for natural gas production and combustion as well as for all fuel sources in the 

electricity grid come from the US LCI database. The state-level average emissions rates 

per GWh (MBtu) of electricity generated are obtained from the 2007 Emissions and 

Generation Resource Integrated Database (eGRID2007), which is a collection of data 

from the EIA, the Federal Energy Regulatory Commission (FERC), and the 

Environmental Protection Agency (EPA). 13 Table A-5 in Appendix A shows variation in 

the emissions rates for the top three greenhouse gases by state, which results from 

differing fuel mixes used for electricity generation in a state.14 

These greenhouse gas emissions are converted into a common unit of measure called 

carbon dioxide equivalents (CO2e) using equivalency factors reported in Table 5-1, which 

represent the global warming potential (GWP) of one unit of greenhouse gas relative to 

that of the same amount of carbon dioxide. For example, one unit of methane has 25 

times the GWP as the same amount of carbon dioxide, and nitrous oxide has 298 times 

the GWP as carbon dioxide. The aggregated CO2e is calculated by taking the amount of 

12 For states located in more than one NERC sub-region, a weighted average of emissions rates for the
 

multiple sub-regions is implemented.
 

13 Emissions rates are held constant over all study periods.
 14 While carbon assessment of building construction, maintenance, repair, and replacement is currently
 

excluded from the analysis, it is currently under development and will be included in future versions of this
 

work.
 

18
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Analysis Approach 

each flow multiplied by its CO2e factor, and summing the resulting CO2 equivalencies. 

The results are analyzed in metric tons of CO2e emissions, and will be referred to as 

“carbon emissions” for the remainder of the report. 

Table 5-1 Greenhouse Gas Global Warming Potentials 

Environmental Flow GWP (CO2e) 

Carbon Dioxide (CO2) 1 

Methane (CH4) 25 

Nitrous Oxide (N2O) 298 

Ethane, 1,1-difluoro-, HFC-152a 124 

Ethane, 1,1,1-trichloro-, HCFC-140 146 

Ethane, 1,1,1,2-tetrafluoro-, HFC-134a 1430 

Ethane, 1,1,2-trichloro-1,2,2-trifluoro-, CFC-113 6130 

Ethane, 1,2-dichloro-1,1,2,2-tetrafluoro-, CFC-114 10 000 

Ethane, hexafluoro-, HFC-116 12 200 

Methane, bromo-, Halon 1001 5 

Methane, bromochlorodifluoro-, Halon 1211 1890 

Methane, bromotrifluoro-, Halon 1301 7140 

Methane, chlorodifluoro-, HCFC-22 1810 

Methane, dichloro-, HCC-30 9 

Methane, dichlorodifluoro-, CFC-12 10 900 

Methane, monochloro-, R-40 13 

Methane, tetrachloro-, CFC-10 1400 

Methane, tetrafluoro-, CFC-14 7390 

Methane, trichlorofluoro-, CFC-11 4750 

Methane, trifluoro-, HFC-23 14 800 

5.4 Analysis Metrics 

The average percentage energy use savings, energy cost savings, life-cycle cost savings, 

and energy-related carbon emissions reductions are calculated by taking the simple 

average of the percentage savings for each location-building type combination in the state 

or nation. The average of the percentage change is used instead of using the average 

change in total values for the state or nation because that would in effect give greater 

weight to buildings or locations with greater total changes. The simple average approach 

used in this study weights each location-building type equally. 

The estimated change in total energy use, energy costs, energy-related carbon emissions, 

and life-cycle costs for each of the building types is combined with new commercial 

building construction data to calculate the magnitude of the available total savings a state 

may realize if it were to adopt a more energy efficient standard as its state energy code. 

The total change per unit of floor area is multiplied by the average annual floor area of 

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Analysis Approach 

new construction for 2003 to 2007, discussed in Section 4.2, which results in the total 

savings over the study period for a single year’s worth of new construction in a state. 

5.5 States Selected for Detailed Analysis 

Detailed analysis of all 50 states is beyond the scope of this study. Certain states are 

chosen to illustrate the detailed analysis possible with the powerful BIRDS database 

compiled for this study. A number of criteria are used to choose the selected states. First, 

it was of interest to select states from across the country. The states chosen represent the 

West Coast, East Coast, Midwest, South, Central U.S., and Alaska. Second, each edition 

of ASHRAE 90.1 should be represented by the selected states. Third, states should 

represent a range of state rankings in terms of volume of new construction for 2003 

through 2007. Fourth, at least 2 states must have adopted the same edition of ASHRAE 

90.1 to illustrate a comparison across states. Finally, it was important to limit the number 

of states for detailed analysis. Based on these criteria, the 7 states in Table 5-2 were 

selected for this study: Alaska, Colorado, Florida, Maryland, Oregon, Tennessee, and 

Wisconsin. The results for each of these 7 states are analyzed in the following chapters. 

Table 5-2 Selection Criteria Values for States Analyzed in Detail (2003 to 2007) 

State Standard 

Edition 

New Floor Area 

1000 m2 (1000 f2

) 

Floor Area 

Ranking 

FL 2007 82 712 (890 306) 1 

MD 2007 16 924 (182 163) 16 

CO 2001 16 461 (177 186) 17 

TN 2004 16 360 (176 095) 18 

WI 2007 11 928 (128 395) 22 

OR 2007 8727 (93 941) 27 

AK None 1448 (15 581) 46 

It is necessary to assume a particular study period length to generate results. Although the 

annual energy use savings and energy-related carbon emissions reductions, both in 

percentage and total value terms, are the same across study period lengths, the energy 

costs and life-cycle costs vary with the study period length because costs vary 

year-over-year. A 10-year study period is used for the majority of this analysis because it 

is the most realistic investor time frame of the 9 study period length options. 

20
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6 

Alaska 

Alaska 

Alaska is selected for this study for two reasons. First, Alaska represents the states that 

have not yet adopted a state energy code for commercial buildings. Second, the state 

represents the two coldest climate zones in the United States. Third, Alaska represents the 

bottom 10 states in terms of new construction volume. For this study, Alaska is assumed 

to build to the current minimum industry practices represented by ASHRAE 90.1-1999 

requirements. 

Table 6-1 provides an overview of Alaska’s simulated energy use keyed to building types 

and energy standard editions. Average energy use varies across building types and 

building designs. The 8-story office building uses the least amount of energy at 

113 kWh/m2 to 140 kWh/m2 (36 kBtu/ft2 to 44 kBtu/ft2

) annually. The high school uses 

the greatest amount of energy at 448 kWh/m2 to 480 kWh/m2 (142 kBtu/ft2 to 

152 kBtu/ft2

) annually. 

Table 6-1 Average Annual Energy Use by Building Type and Energy Code, Alaska 

Building 

Type 

Energy Code 

1999 

kWh/m2 kBtu/ft2 

2001 

kWh/m2 kBtu/ft2 

2004 

kWh/m2 kBtu/ft2 

2007 

kWh/m2 kBtu/ft2 

LEC 

kWh/m2 kBtu/ft2 

APART04 

APART06 

270 86 

265 84 

270 86 

265 84 

269 85 

264 84 

258 82 

253 80 

239 76 

236 75 

DORMI04 

DORMI06 

228 72 

286 91 

228 72 

286 91 

231 73 

288 91 

218 69 

275 87 

192 61 

258 82 

HOTEL15 263 84 263 83 263 84 276 87 250 79 

HIGHS02 480 152 480 152 481 153 473 150 448 142 

OFFIC03 

OFFIC08 

OFFIC16 

171 54 

140 44 

223 71 

171 54 

139 44 

222 70 

172 55 

137 44 

223 71 

162 51 

134 43 

236 75 

131 42 

113 36 

209 66 

RETAIL1 219 70 219 69 221 70 207 66 166 53 

RSTRNT1 286 91 285 90 291 92 257 82 197 63 

The detailed analysis for this state reports the changes in energy use, energy costs, 

energy-related carbon emissions, and life-cycle costs from adoption of increasingly 

stringent energy standard editions. The results are reported in terms of average 

percentage savings on a statewide and city-by-city basis and as total savings on a 

statewide basis. 

21
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Alaska 

6.1 Percentage Savings 

Changes in percentage terms allow for direct comparisons across building types and 

locations within a state. This section discusses the average percentage changes from 

investing in more energy efficient designs for the state of Alaska. 

6.1.1 Energy Use 

Table 6-2 shows the percentage changes in energy use for Alaska. There is minimal 

change in energy use from adopting ASHRAE 90.1-2001 relative to ASHRAE 90.1-1999 

with all 11 building types having reductions in energy use of 0.7 % or less. There is a 

small decrease in energy use for 9 of 11 building types for ASHRAE 90.1-2004, with the 

percentage change in energy use ranging from 0.6 % to -3.4 % with an average of -0.8 %. 

The average change in energy use from constructing buildings using ASHRAE 90.1-2007 

requirements ranges from 4.0 % to -12.4 %, with an overall average of -4.8 %. 

Table 6-2 Average Percentage Change in Energy Use from Adoption of Newer 

Codes, Alaska 

Building Energy Code
 

Type
 2001 2004 2007 LEC 

APART04 -0.1 -1.2 -5.6 -12.7 

APART06 -0.1 -1.3 -5.5 -12.2 

DORMI04 -0.2 0.2 -6.5 -18.1 

DORMI06 -0.1 -0.2 -5.1 -11.1 

HOTEL15 -0.2 -1.0 2.7 -6.9 

HIGHS02 0.0 -0.2 -2.4 -7.7 

OFFIC03 -0.4 -1.0 -8.0 -25.5 

OFFIC08 -0.7 -3.4 -6.0 -21.3 

OFFIC16 -0.3 -0.7 4.0 -8.1 

RETAIL1 -0.1 -0.5 -8.4 -26.3 

RSTRNT1 -0.3 0.6 -12.4 -33.4 

Average -0.2 -0.8 -4.8 -16.7 

The ASHRAE 90.1-2004 and ASHRAE 90.1-2007 designs realize an increase for some 

building types. The key driver is the consolidation of the 26 climate zones in ASHRAE 

90.1-2001 down to 8 climate zones in ASHRAE 90.1-2004 and ASHRAE 90.1-2007, 

which resulted in changes in building envelope requirements for some locations in the 

state, including relaxation of the maximum window U-factor requirement and insulation 

R-value minimum requirements. Given the cold climate in Alaska, the relaxation of these 

requirements leads to increases in natural gas consumption. 

For the high-rise, 100 % glazed buildings (16-story office building and 15-story hotel), 

ASHRAE 90.1-2004 is actually more energy efficient than ASHRAE 90.1-2007 because 

the maximum window SHGC in Zone 7 and Zone 8 is decreased from ASHRAE 

90.1-2004 to ASHRAE 90.1-2007, making the requirement stricter. Buildings in colder 

22
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Alaska 

climates benefit from additional solar heat gains. The 100 % glazing amplifies the lost 

heat gain from the lower SHGC, which increases natural gas consumption enough to 

overwhelm the energy efficiency gains obtained from other measures that decrease 

energy consumption, such as increased roof insulation R-values. 

The LEC design realizes the greatest reductions in energy use, with the change in energy 

use relative to ASHRAE 90.1-1999 ranging from -6.9 % to -33.4 % with an average 

of -16.7 %. Similar to the ASHRAE 90.1-2007 design, the lowest reduction in energy use 

for the LEC design occurs in the buildings with the greatest window-to-wall ratios due to 

the stricter window SHGC requirement. 

6.1.2 Energy Costs 

Table 6-3 shows minimal change in energy costs over 10 years from adopting ASHRAE 

90.1-2001 (-0.1 % to -1.0 %), which mirrors the energy use results described above. 

There is a significant variation in the percentage change in average energy costs for 

ASHRAE 90.1-2004, ranging from -5.6 % to -18.0 % depending on the building type, 

with an average of -12.7 %. The average change in energy costs from constructing 

buildings using ASHRAE 90.1-2007 requirements ranges from -3.2 % to -21.1 %, with an 

overall average of -14.3 %. The LEC design realizes the greatest change in energy costs, 

with the average change by building type ranging from -14.9 % to -40.1 % with an 

average of -27.6 % overall. 

Table 6-3 Average Percentage Change in Energy Costs, 10-Year, Alaska 

Building Energy Code 

Type 2001 2004 2007 LEC 

APART04 -0.1 -17.8 -20.2 -31.2 

APART06 -0.1 -18.0 -20.3 -31.1 

DORMI04 -0.4 -17.8 -21.1 -34.8 

DORMI06 -0.2 -17.1 -19.9 -30.0 

HOTEL15 -0.4 -16.2 -12.9 -23.5 

HIGHS02 -0.1 -5.6 -7.1 -17.8 

OFFIC03 -0.6 -8.1 -10.6 -27.6 

OFFIC08 -1.0 -9.9 -10.8 -25.8 

OFFIC16 -0.6 -6.9 -3.2 -14.9 

RETAIL1 -0.2 -10.8 -13.9 -27.3 

RSTRNT1 -0.6 -11.1 -17.0 -40.1 

Average -0.4 -12.7 -14.3 -27.6 

For all building designs, the reductions in energy costs are greater than the reductions in 

energy use because the percentage reduction in electricity consumption is greater than the 

reduction in natural gas consumption. In the most extreme cases, electricity consumption 

is decreased while natural gas consumption is increased. The buildings use electricity for 

all energy consumption except for the heating component of the HVAC system, which 

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Alaska 

uses natural gas. The energy efficiency measures adopted may lead to a decrease in 

energy use for both lighting and cooling the building while increasing heating loads. 

Since electricity is more expensive than natural gas on a per unit of energy basis, the shift 

in energy use from cooling to heating magnifies the decrease in energy costs for the 

building. 

6.1.3 Energy-related Carbon Emissions 

Minimal change in energy use leads to small changes (less than 1 %) in cradle-to-grave 

energy-related carbon emissions for the ASHRAE 90.1-2001 design across all building 

types. Table 6-4 shows a significant change in average energy-related carbon emissions 

for ASHRAE 90.1-2004 for all building types, ranging from -3.6 % to -12.5 % with an 

average of -8.9 %. The ASHRAE 90.1-2007 design leads to slightly greater reductions 

than ASHRAE 90.1-2004, with the average change in carbon emissions ranging 

from -1.0 % to -16.3 % with an overall average of -11.1 %. The LEC design leads to the 

greatest average carbon emissions changes, ranging from -12.9 % to -37.9 % depending 

on the building type with an average of -24.0 % across all building types. 

Table 6-4 Average Percentage Change in Energy-related Carbon Emissions, 10­

Year, Alaska 

Building Energy Code 

Type 2001 2004 2007 LEC 

APART04 -0.1 -12.2 -15.3 -25.0 

APART06 -0.1 -12.5 -15.4 -24.8 

DORMI04 -0.3 -12.0 -16.3 -29.3 

DORMI06 -0.1 -11.4 -14.9 -23.7 

HOTEL15 -0.3 -11.2 -7.7 -18.0 

HIGHS02 -0.1 -3.6 -5.3 -14.0 

OFFIC03 -0.5 -6.0 -9.7 -26.9 

OFFIC08 -0.9 -8.2 -9.5 -24.6 

OFFIC16 -0.5 -5.1 -1.0 -12.9 

RETAIL1 -0.1 -7.7 -12.1 -26.8 

RSTRNT1 -0.5 -7.5 -15.4 -37.9 

Average -0.3 -8.9 -11.1 -24.0 

As would be expected, a more energy efficient building design results in greater 

reductions in carbon emissions. Similar to energy costs, the percentage changes in carbon 

emissions are greater than the percentage changes in energy use because the energy 

efficiency measures decrease electricity consumption by a greater percentage than natural 

gas consumption. The greater relative reduction in electricity consumption further 

decreases carbon emissions because electricity has a higher carbon emissions rate per unit 

of energy than natural gas in Alaska. 

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Alaska 

6.1.4 Life-Cycle Costs 

The most cost-effective building design for each building type is bolded in Table 6-5. 

Life-cycle costs increase for the ASHRAE 90.1-2001 design compared to ASHRAE 

90.1-1999 for all building types over a 10-year study period. ASHRAE 90.1-1999 is the 

lowest cost building design for one building type while ASHRAE 90.1-2004 and ASHRAE 

90.1-2007 are the lowest cost building design for two and four building types, 

respectively. The change in life-cycle costs for ASHRAE 90.1-2004 and -2007 range 

from -2.6 % to 2.7 % depending on building type. The LEC design realizes a reduction in 

life-cycle costs for 10 of 11 building types, with the percentage change in life-cycle costs 

ranging from -2.4 % to 1.0 %. 

Table 6-5 Average Percentage Change in Life-Cycle Costs, 10-Year, Alaska 

Building Energy Code 

Type 2001 2004 2007 LEC 

APART04 0.1 -1.8 -2.3 -1.7 

APART06 0.0 -1.8 -2.2 -1.5 

DORMI04 2.2 -1.1 -1.8 -2.4 

DORMI06 0.0 -2.2 -2.6 -2.2 

HOTEL15 0.0 -2.5 -2.1 -1.8 

HIGHS02 0.4 -0.4 -0.7 -1.6 

OFFIC03 3.6 1.6 0.9 -0.5 

OFFIC08 3.7 1.5 1.1 -0.0 

OFFIC16 0.0 -0.9 -0.4 -0.2 

RETAIL1 1.7 0.0 -0.7 -0.2 

RSTRNT1 4.5 2.7 2.4 1.0 

Average 1.5 -0.5 -0.8 -1.0 

6.1.5 City Comparisons 

Simulations are run for 6 cities located in Alaska: Anchorage, Juneau, and Kodiak in 

Climate Zone 7 and Barrow, Fairbanks, and Nome in Climate Zone 8. The results vary 

across cities within Alaska for several reasons. First, the state is covered by two climate 

zones. The ASHRAE 90.1 building design requirements vary across climate zones and 

will impact the relative energy efficiency of the building. Second, cities within the same 

climate zone still have some variation in the local climate, which can lead to variation in 

energy consumption. Third, construction material and labor costs vary by locality. 

As can be seen in Table 6-6, average reduction in energy use for all building types from 

adopting newer energy standard editions is greater for the cities located in Zone 7. For the 

LEC design, Zone 7 realizes a change in average energy use of -23.1 % compared 

to -10.2 % for Zone 8. The extreme case is Barrow, which realizes an energy use increase 

of over 10 % for both ASHRAE 90.1-2004 and ASHRAE 90.1-2007 relative to ASHRAE 

90.1-1999. 

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Alaska 

Table 6-6 Average Percentage Change in Energy Use from Adoption of Newer 

Codes by City, Alaska 

Cities Zone Energy Code 

2001 2004 2007 LEC 

Anchorage 7 -0.3 -3.0 -10.5 -22.0 

Juneau 7 -0.2 -3.6 -11.7 -23.1 

Kodiak 7 -0.3 -4.4 -12.0 -24.2 

Barrow 8 -0.1 10.8 10.6 -1.6 

Fairbanks 8 -0.3 -2.5 -3.1 -14.6 

Nome 8 -0.2 -2.1 -2.4 -14.4 

Average -0.2 -0.8 -4.8 -16.7 

The variations in energy costs across cities are a result of two factors, the reductions in 

energy use and the fuel source of the reduction. Table 6-7 shows that the average 

reduction in energy costs for all building types is lower for cities in Zone 8 relative to 

cities in Zone 7. For the LEC design, Zone 7 realizes an average change in energy costs 

of -31.9 % compared to -23.4 % for Zone 8. 

The percentage change in energy costs is greater than the percentage change in energy 

use because the percentage reduction in electricity consumption is greater than the 

reduction in natural gas consumption. In some cases, electricity consumption is decreased 

while natural gas consumption is increased. Nowhere is this more apparent than in 

Barrow, Alaska. Even though Barrow has an increase in total energy use of 11 %, it 

realizes a decrease in energy costs of over 4 % for both ASHRAE 90.1-2004 and ASHRAE 

90.1-2007 relative to ASHRAE 90.1-1999. The lower cost of natural gas use relative to 

electricity use is significant enough to overwhelm the increase in total energy use. 

Table 6-7 Average Percentage Change in Energy Costs by City, 10-Year, Alaska 

Cities Zone Energy Code 

2001 2004 2007 LEC 

Anchorage 7 -0.5 -15.0 -17.9 -31.4 

Juneau 7 -0.4 -15.4 -18.4 -31.6 

Kodiak 7 -0.4 -16.3 -18.7 -32.8 

Barrow 8 -0.1 -4.4 -4.8 -17.6 

Fairbanks 8 -0.6 -12.2 -12.8 -26.0 

Nome 8 -0.3 -12.6 -12.9 -26.4 

Average -0.4 -12.7 -14.3 -27.6 

Table 6-8 reports changes in energy-related carbon emissions by city for Alaska. For 5 of 

the 6 cities, the more stringent standard editions result in greater reductions in carbon 

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Alaska 

emissions. As with energy use, the cities in Zone 7 realize a greater average change in 

emissions than the cities in Zone 8, -29.0 % versus -18.5 % for the LEC design, on 

average. For both Zone 7 and Zone 8, adopting ASHRAE 90.1-2004 and ASHRAE 

90.1-2007 would decrease energy-related carbon emissions overall. Barrow realizes an 

increase in average carbon emissions for ASHRAE 90.1-2004 and ASHRAE 90.1-2007, 

which is driven by the increase in energy use. 

Table 6-8 Average Percentage Change in Carbon Emissions by City, 10-Year, 

Alaska 

Cities Zone Energy Code 

2001 2004 2007 LEC 

Anchorage 7 -0.4 -10.9 -15.2 -28.2 

Juneau 7 -0.3 -11.4 -16.0 -28.8 

Kodiak 7 -0.4 -12.4 -16.4 -30.0 

Barrow 8 -0.1 1.2 0.8 -11.7 

Fairbanks 8 -0.4 -8.5 -9.2 -21.8 

Nome 8 -0.3 -8.7 -9.1 -22.1 

Average -0.3 -8.9 -11.1 -23.8 

The data reported in Table 6-9 show that, over a 10-year period, average life-cycle costs 

increase for all cities for the ASHRAE 90.1-2001 design compared to ASHRAE 

90.1-1999. The ASHRAE 90.1-2007 and LEC designs result in the lowest average 

life-cycle costs of all building design alternative for one city and 4 cities, respectively. 

For the ASHRAE 90.1-2001, -2004, -2007 and LEC designs, the cities located in Zone 7 

realize smaller increases and/or greater decreases in their average percentage changes in 

life-cycle costs than cities in Zone 8. The adoption of any of the newer standard editions 

increases life-cycle costs for the city of Barrow. 

Table 6-9 Average Percentage Change in Life-Cycle Costs by City, 10-Year, Alaska 

Cities Zone Energy Code 

2001 2004 2007 LEC 

Anchorage 7 1.5 -0.8 -1.3 -1.5 

Juneau 7 1.5 -0.8 -1.4 -1.4 

Kodiak 7 1.4 -0.9 -1.1 -1.3 

Barrow 8 1.4 0.4 0.3 0.0 

Fairbanks 8 1.5 -0.2 -0.4 -1.0 

Nome 8 1.4 -0.5 -0.5 -0.9 

Average 1.5 -0.5 -0.8 -1.0 

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Alaska 

6.2 Total Savings 

How much can Alaska save, in terms of energy use, energy costs, and carbon emissions, 

from adopting a more stringent state energy code for commercial buildings? What are the 

life-cycle costs associated with the new energy code adoption? To answer these 

questions, it is first necessary to estimate savings per unit of floor area for each building 

type in the state. 

6.2.1 Energy Use 

Table 6-10 reports the average per unit change in annual energy use by building type and 

building design in the state.15 The reduction per m2 (ft2

) is multiplied by the estimated m2 

(ft2) of new construction of each building type. Table 6-11 reports the estimated average 

annual floor area of new construction and the total annual change in energy use for each 

building type. The weightings within a category (e.g. small, medium, and large office 

buildings) are based on the national average percentage of new building construction for 

the category that is represented by each subcategory.16 

Table 6-10 Average Per Unit Change in Annual Energy Use, Alaska 

Building Energy Code 

Type 2001 

kWh/m2 kBtu/ft2 

2004 

kWh/m2 kBtu/ft2 

2007 

kWh/m2 kBtu/ft2 

LEC 

kWh/m2 kBtu/ft2 

APART04 

APART06 

-0.1 -0.0 

-0.2 -0.0 

-1.4 -0.5 

-1.6 -0.5 

-12.6 -4.0 

-12.0 -3.8 

-31.7 -10.0 

-29.6 -9.4 

DORMI04 

DORMI06 

-0.4 -0.1 

-0.2 -0.1 

3.4 1.1 

1.7 0.5 

-10.6 -3.4 

-10.9 -3.5 

-36.5 -11.6 

-27.7 -8.8 

HOTEL15 -0.5 -0.2 -0.2 -0.1 12.1 3.8 -13.0 -4.1 

HIGHS02 -0.1 -0.0 0.7 0.2 -10.0 -3.2 -40.2 -12.7 

OFFIC03 

OFFIC08 

OFFIC16 

-0.6 -0.2 

-1.0 -0.3 

-0.7 -0.2 

1.3 0.4 

-3.0 -1.0 

0.4 0.1 

-6.8 -2.1 

-6.1 -1.9 

13.1 4.2 

-31.8 -10.1 

-27.5 -8.7 

-13.9 -4.4 

RETAIL1 -0.2 -0.1 2.0 0.6 -12.5 -4.0 -52.7 -16.7 

RSTRNT1 -0.9 -0.3 5.0 1.6 -28.4 -9.0 -88.2 -28.0 

The total annual reduction in energy use ranges widely across building designs, but the 

ASHRAE 90.1-2001, ASHRAE 90.1-2007, and LEC designs all decrease overall energy 

use across the state. Adopting ASHRAE 90.1-2001 results in an annual decrease of 

65.0 MWh (221.9 MBtu) while adopting ASHRAE 90.1-2007 saves 793.1 MWh 

(2.7 GBtu) annually. The adoption of the LEC design as the state’s energy code would 

save energy for all building types and 5.6 GWh (19.3 GBtu) of total energy use annually 

15 A simple average for a state is used because no data for a weighted average is available regarding the
 

amount of new construction on a city-by-city basis.
 

16 State-level subcategory data are not available.
 

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Alaska 

for one year’s worth of new construction for these building types. The adoption of the 

ASHRAE 90.1-2004 design increases total annual energy use by 106 821 kWh 

(365 MBtu) even though the overall average percentage change in energy use is negative 

for this building design. This emphasizes the importance of estimating aggregate impacts 

instead of relying solely on simple average percentage changes. 

Table 6-11 Statewide Change in Annual Energy Use for One Year of Construction, 

Alaska 

Building 

Type 

Subcat. 

Weight. m 2 

(1000s) 

ft2 

(1000s) 

Energy Code 

2001 

MWh MBtu 

2004 

MWh MBtu 

2007 

MWh MBtu 

LEC 

MWh MBtu 

APART04 

APART06 

44.9 % 

55.1 % 

1.7 

2.0 

18 

22 

-0 -1 

-0 -1 

-2 -8 

-3 -11 

-21 -72 

-25 -84 

-53 -182 

-61 -208 

HOTEL15 100.0 % 25.2 271 -13 -43 -5 -16 304 1038 -328 -1120 

HIGHS02 100.0 % 46.2 497 -6 -20 59 203 -312 -1065 -1467 -5010 

OFFIC03 

OFFIC08 

OFFIC16 

37.4 % 

40.4 % 

22.2 % 

16.9 

18.2 

10.0 

182 

196 

108 

-11 -36 

-18 -62 

-7 -24 

12 42 

-55 -187 

4 15 

-168 -575 

-111 -379 

131 448 

-678 -2315 

-501 -1712 

-139 -476 

RETAIL1 100.0 % 41.6 448 -8 -27 83 285 -519 -1771 -2194 -7491 

RSTRNT1 100.0 % 2.5 27 -2 -8 13 44 -72 -247 -225 -767 

Total 164.3 1769 -65 -222 107 365 -793 -2708 -5646 -19 279 

Note: Dormitories are excluded because no floor area category is reported in the construction data. 

Assuming that the buildings considered in this study, which represent 56.8 % of all new 

commercial floor space in the state, are generally representative of the entire new 

commercial building stock in the state, the results can be extrapolated to estimate the total 

statewide savings from LEC adoption in new commercial buildings to be 9.9 GWh 

(33.9 GBtu) per year. These savings imply 99.4 GWh (339 GBtu) in energy savings over 

the 10-year study period. In comparison, ASHRAE 90.1-2007 would save 1.4 GWh 

(4.8 GBtu) annually or 14.0 GWh (47.7 GBtu) over the 10-year study period. 

The relative reduction in energy use across the 9 building types with reported floor area 

data varies by building design. The greatest reductions for ASHRAE 90.1-2004 are found 

in mid-sized office buildings while for the ASHRAE 90.1-2007 and LEC designs, the 

greatest reductions are realized by retail stores and high schools. ASHRAE 90.1-2004 and 

ASHRAE 90.1-2007 result in an increase in energy use for 5 and 2 building types, 

respectively. The ASHRAE 90.1-2004 design increases total energy use for the low-rise 

and high-rise office buildings, high schools, retail stores, and restaurants relative to 

ASHRAE 90.1-1999 because of the changes in building envelope requirements for cities 

in Zone 8 as a result of the condensing of climate zones. Interestingly, four of these 

building types realized small average percentage decreases in energy use (see Table 6-2), 

which emphasizes the importance of estimating the total energy use impacts. For the 

ASHRAE 90.1-2007 design, the two high-rise buildings with 100 % window glazing 

realize increases in statewide energy use because of the relaxation of window U-factors 

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Alaska 

and stricter window SHGC requirements for cities in Zone 8. The adoption of ASHRAE 

90.1-2007 leads to an increase in natural gas consumption that overwhelms any reduction 

in electricity consumption. 

The statewide change in energy use varies across building types within a building design. 

Building types that represent a greater amount of new floor area realize the largest 

changes in aggregate energy use. The building types that have the greatest percentage 

reduction in energy use are not always the same buildings that lead to the greatest total 

reductions for the state. For example, the building types that lead to the greatest estimated 

reductions in energy use for the LEC design -- retail stores and high schools -- rank 2nd 

and 10th in percentage reduction, respectively, among the 11 building types, as reported 

in Table 6-2. 

6.2.2 Energy Costs 

Table 6-12 reports the average per unit change in energy costs by building type and 

building design. Energy costs are calculated using the annual energy use, state average 

energy cost rates, and regional energy price escalation rates as defined in Section 3.2. 

Table 6-12 Average Per Unit Change in Energy Costs, 10-Year, Alaska 

Building Energy Code 

Type 2001 

$/m2 $/ft2 

2004 

$/m2 $/ft2 

2007 

$/m2 $/ft2 

LEC 

$/m2 $/ft2 

APART04 

APART06 

-$0.16 

-$0.18 

-$0.01 

-$0.02 

-$23.51 

-$23.74 

-$2.18 

-$2.21 

-$26.75 

-$26.81 

-$2.48 

-$2.49 

-$41.65 

-$41.31 

-$3.87 

-$3.84 

DORMI04 

DORMI06 

-$0.46 

-$0.23 

-$0.04 

-$0.02 

-$21.19 

-$24.34 

-$1.97 

-$2.26 

-$25.09 

-$28.29 

-$2.33 

-$2.63 

-$41.88 

-$43.04 

-$3.89 

-$4.00 

HOTEL15 -$0.57 -$0.05 -$22.32 -$2.07 -$17.41 -$1.62 -$32.41 -$3.01 

HIGHS02 -$0.14 -$0.01 -$10.57 -$0.98 -$13.23 -$1.23 -$34.63 -$3.22 

OFFIC03 

OFFIC08 

OFFIC16 

-$0.72 

-$1.15 

-$0.80 

-$0.07 

-$0.11 

-$0.07 

-$9.31 

-$11.08 

-$9.78 

-$0.87 

-$1.03 

-$0.91 

-$12.26 

-$12.07 

-$4.16 

-$1.14 

-$1.12 

-$0.39 

-$32.47 

-$29.13 

-$21.37 

-$3.02 

-$2.71 

-$1.99 

RETAIL1 -$0.22 -$0.02 -$14.11 -$1.31 -$17.99 -$1.67 -$36.17 -$3.36 

RSTRNT1 -$1.03 -$0.10 -$18.87 -$1.75 -$28.78 -$2.67 -$68.99 -$6.41 

Table 6-13 reports the statewide changes in total energy costs by building type and 

building design, which account for one year’s worth of new construction evaluated over 

10 years of building operation. The ASHRAE 90.1-2001 design realizes small reductions 

in energy costs ($74 323). ASHRAE 90.1-2004, ASHRAE 90.1-2007, and the LEC design 

realize decreases in energy costs of $2.2 million, $2.4 million, and $5.5 million 

respectively. All the building types that realize an increase in total energy use from the 

adoption of the ASHRAE 90.1-2004 or ASHRAE 90.1-2007 designs realize a decrease in 

30
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Alaska 

total energy costs because the increase in natural gas costs is less than the decrease in 

electricity costs. 

Assuming that the buildings considered in this study, which represent 56.8 % of all new 

commercial floor space in the state, are generally representative of the entire new 

commercial building stock in the state, the results for ASHRAE 90.1-2001, ASHRAE 

90.1-2004, ASHRAE 90.1-2007, and the LEC design can be extrapolated to estimate 

statewide reductions in energy costs of $130 850, $3.9 million, $4.3 million, and 

$9.8 million over the 10-year study period, respectively. 

Table 6-13 Statewide Change in Energy Costs for One Year of Construction, 

10-Year, Alaska 

Building Subcategory m 2 ft2 Energy Code 

Type Weighting (1000s) (1000s) 2001 2004 2007 LEC 

APART04 44.9 % 1.7 18 -$265 -$39 458 -$44 896 -$69 920 

APART06 55.1 % 2.0 22 -$365 -$48 803 -$55 121 -$84 935 

HOTEL15 100 % 25.2 271 -$14 307 -$562 750 -$438 938 -$817 228 

HIGHS02 100 % 46.2 497 -$6672 -$488 114 -$611 097 -$1 599 031 

OFFIC03 37.4 % 16.9 182 -$12 104 -$157 269 -$207 099 -$548 262 

OFFIC08 40.4 % 18.2 196 -$20 863 -$201 693 -$219 820 -$530 469 

OFFIC16 22.2 % 10.0 108 -$8054 -$97 980 -$41 692 -$214 100 

RETAIL1 100 % 41.6 448 -$9068 -$587 353 -$748 800 -$1 505 613 

RSTRNT1 100 % 2.5 27 -$2624 -$48 044 -$73 271 -$175 609 

Total 164.3 1769 -$74 323 -$2 231 464 -$2 440 734 -$5 545 167 

Note: Dormitories are excluded because no floor area category is reported in the construction data. 

6.2.3 Energy-related Carbon Emissions 

Table 6-14 reports the average reduction in energy-related carbon emissions over 10 

years, per m 

2 (ft2

), by building type and building design. The carbon emissions estimation 

approach is defined in Section 5.3. 

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Alaska 

Table 6-14 Average Per Unit Change in Carbon Emissions, 10-Year, Alaska
 

Building Energy Code 

Type 2001 

kg/m2 lb/ft2 

2004 

kg/m2 lb/ft2 

2007 

kg/m2 lb/ft2 

LEC 

kg/m2 lb/ft2 

APART04 -0.9 -0.2 -112.5 -23.0 -141.7 -29.0 -235.8 -48.3 

APART06 -1.0 -0.2 -113.8 -23.3 -141.3 -28.9 -231.5 -47.4 

DORMI04 -2.6 -0.5 -95.6 -19.6 -131.4 -26.9 -242.9 -49.7 

DORMI06 -1.3 -0.3 -112.6 -23.1 -146.8 -30.1 -237.3 -48.6 

HOTEL15 -3.3 -0.7 -105.3 -21.6 -66.9 -13.7 -168.9 -34.6 

HIGHS02 -0.8 -0.2 -48.2 -9.9 -70.8 -14.5 -202.9 -41.5 

OFFIC03 -4.2 -0.9 -43.0 -8.8 -70.2 -14.4 -203.1 -41.6 

OFFIC08 -6.6 -1.4 -55.9 -11.5 -64.5 -13.2 -171.6 -35.2 

OFFIC16 -4.7 -1.0 -45.5 -9.3 -3.2 -0.7 -118.0 -24.2 

RETAIL1 -1.3 -0.3 -64.0 -13.1 -100.3 -20.5 -236.3 -48.4 

RSTRNT1 -6.0 -1.2 -82.6 -16.9 -171.1 -35.0 -435.3 -89.1 

Table 6-15 applies the Table 6-14 results to one year’s worth of new building 

construction in the state to estimate statewide reduction in carbon emissions from 

adoption of more energy efficient codes. The total reduction in carbon emissions ranges 

widely across building designs, but the ASHRAE 90.1-2001, ASHRAE 90.1-2004, 

ASHRAE 90.1-2007, and LEC designs decrease carbon emissions overall. The adoption 

of ASHRAE 90.1-2004 and ASHRAE 90.1-2007 result in savings of 10 375 metric tons 

and 12 486 metric tons over a 10-year study period, respectively. All building types that 

realized an increase in total energy use from adopting ASHRAE 90.1-2004 or ASHRAE 

90.1-2007 realize a decrease in carbon emissions because the emissions resulting from 

the increase in natural gas consumption are less than the decrease in emissions from the 

reduction in electricity consumption. The adoption of LEC as the state’s energy code 

decreases carbon emissions by 33 177 metric tons over the 10-year study period for one 

year’s worth of new commercial construction for these building types. 

Assuming that the buildings considered in this study are generally representative of the 

entire new commercial building stock in the state, the results for ASHRAE 90.1-2004, 

ASHRAE 90.1-2007, and LEC can be extrapolated to estimate statewide reductions in 

carbon emissions of 18 265 tons, 21 983 tons, and 58 411 tons over the 10-year study 

period, respectively. 

32
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Alaska 

Table 6-15 Statewide Change in Total Carbon Emissions for One Year of 

Construction, 10-Year, Alaska – Metric Tons 

Building Subcategory m 2 ft2 Energy Code 

Type Weighting (1000s) (1000s) 2001 2004 2007 LEC 

APART04 44.9 % 1.7 18 -2 -189 -238 -396 

APART06 55.1 % 2.0 22 -2 -234 -291 -476 

HOTEL15 100.0 % 25.2 271 -83 -2656 -1687 -4259 

HIGHS02 100.0 % 46.2 497 -39 -2224 -3268 -9366 

OFFIC03 37.4 % 16.9 182 -70 -725 -1186 -3430 

OFFIC08 40.4 % 18.2 196 -121 -1018 -1174 -3125 

OFFIC16 22.2 % 10.0 108 -47 -456 -32 -1183 

RETAIL1 100.0 % 41.6 448 -53 -2662 -4175 -9835 

RSTRNT1 100.0 % 2.5 27 -15 -210 -436 -1108 

Total 164.3 1769 -431 -10 375 -12 486 -33 177 

Note: Dormitories are excluded because no floor area category is reported in the construction 

data. 

6.2.4 Life-Cycle Costs 

Table 6-16 reports the average change in life-cycle cost over 10 years, per m2 (ft2

), by 

building type and building design. As discussed in Section 5.2, life-cycle costs include 

construction costs, maintenance, repair, and replacement costs, energy costs, and residual 

values. 

Table 6-16 Average Per Unit Change in Life-Cycle Costs, 10-Year, Alaska 

Building Energy Code 

Type 2001 

$/m2 $/ft2 

2004 

$/m2 $/ft2 

2007 

$/m2 $/ft2 

LEC 

$/m2 $/ft2 

APART04 $1.00 $0.09 -$22.37 -$2.08 -$28.29 -$2.63 -$21.31 -$1.98 

APART06 $0.50 $0.05 -$22.72 -$2.11 -$27.73 -$2.58 -$18.79 -$1.75 

DORMI04 $25.64 $2.38 -$12.22 -$1.14 -$20.47 -$1.90 -$27.80 -$2.58 

DORMI06 $0.23 $0.02 -$29.21 -$2.71 -$34.13 -$3.17 -$28.95 -$2.69 

HOTEL15 -$0.24 -$0.02 -$31.41 -$2.92 -$26.03 -$2.42 -$22.59 -$2.10 

HIGHS02 $4.92 $0.46 -$4.31 -$0.40 -$7.27 -$0.68 -$18.12 -$1.68 

OFFIC03 $35.01 $3.25 $15.85 $1.47 $8.74 $0.81 -$4.79 -$0.44 

OFFIC08 $37.12 $3.45 $15.27 $1.42 $10.66 $0.99 -$0.44 -$0.04 

OFFIC16 -$0.13 -$0.01 -$9.25 -$0.86 -$4.13 -$0.38 -$1.42 -$0.13 

RETAIL1 $13.89 $1.29 -$0.24 -$0.02 -$5.29 -$0.49 -$1.58 -$0.15 

RSTRNT1 $68.46 $6.36 $40.66 $3.78 $35.97 $3.34 $15.27 $1.42 

Table 6-17 applies the Table 6-16 results to one year’s worth of new building 

construction in the state to estimate statewide changes in life-cycle costs from adoption of 

more energy-efficient state energy codes for commercial buildings. Total reductions in 

life-cycle costs over the 10-year study period vary across building designs. Adoption of 

33
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Alaska 

the ASHRAE 90.1-2001 design results in an increase in life-cycle costs for 7 of 9 building 

types. The ASHRAE 90.1-2004 and -2007 designs result in a decrease in life-cycle costs 

for 6 of 9 building types, with total life-cycle costs decreasing by $463 949 and $815 858, 

respectively. The LEC design decreases life-cycle costs for 8 of 9 building types, and 

decreases total life-cycle costs by $1.3 million. The building types that realize a decrease 

in life-cycle costs far outweigh in terms of construction volume the building types that 

realize increases in life-cycle costs for the LEC design. For a 10-year study period, it is 

cost-effective to adopt newer editions of the ASHRAE 90.1-2004, -2007, or the LEC 

design. 

Assuming that the buildings considered in this study are generally representative of the 

entire new commercial building stock in the state, the results for ASHRAE 90.1-2001, 

ASHRAE 90.1-2004, ASHRAE 90.1-2007, and LEC can be extrapolated to estimate 

statewide changes in life-cycle costs of $3.8 million, -$816 812, -$1.4 million, 

and -$2.4 million over the 10-year study period, respectively. 

Table 6-17 Statewide Change in Life-Cycle Costs for One Year of Construction, 

10-Year, Alaska 

Building Subcategory m 2 ft2 Energy Code 

Type Weighting (1000s) (1000s) 2001 2004 2007 LEC 

APART04 44.9 % 1.7 18 $1679 -$37 552 -$47 483 -$35 770 

APART06 55.1 % 2.0 22 $1030 -$46 717 -$57 020 -$38 625 

HOTEL15 100.0 % 25.2 271 -$5984 -$792 009 -$656 255 -$569 600 

HIGHS02 100.0 % 46.2 497 $153 108 -$134 211 -$226 537 -$564 232 

OFFIC03 37.4 % 16.9 182 $591 248 $267 717 $147 535 -$80 821 

OFFIC08 40.4 % 18.2 196 $675 971 $278 128 $194 045 -$8033 

OFFIC16 22.2 % 10.0 108 -$1324 -$92 661 -$41 419 -$14 218 

RETAIL1 100.0 % 41.6 448 $578 191 -$10 138 -$220 286 -$65 841 

RSTRNT1 100.0 % 2.5 27 $174 273 $103 494 $91 562 $38 862 

Total 164.3 1769 $2 168 193 -$463 949 -$815 858 -$1 338 279 

Note: Dormitories are excluded because no floor area category is reported in the construction data. 

6.3 State Summary 

Alaska is one of the states that has no state energy code for commercial buildings, and 

represents the coldest climates in the United States. On average, adopting ASHRAE 

90.1-2004 or ASHRAE 90.1-2007 leads to reductions in energy use, energy costs, and 

cradle-to-grave energy-related carbon emissions at negative life-cycle costs. Based on the 

average annual new construction in the state from 2003 to 2007 and a 10-year study 

period, adopting ASHRAE 90.1-2007 as the state’s energy code for commercial buildings 

would lead to energy savings of 14.0 GWh (47.7 GBtu), energy cost savings of 

$4.3 million, and 21 983 metric tons of carbon emissions reductions while saving 

$1.4 million in life-cycle costs for one year’s worth of commercial building construction. 

34
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

Alaska 

However, adopting the ASHRAE 90.1-2004 or ASHRAE 90.1-2007 design increases 

energy use for some location-building type combinations in Alaska. ASHRAE 90.1-2004 

condenses the 26 climate zones defined in ASHRAE 90.1-1999/2001 into 8 climate zones. 

As a result, some of the building envelope requirements (window U-factors and 

insulation R-values) are slightly less stringent for cities in Zone 8. Additionally, ASHRAE 

90.1-2007 restricts the window SHGC below that required in ASHRAE 90.1-2004 for 

Alaska’s climate zones, leading to losses in beneficial heat gain through fenestration. 

The adoption of the LEC design leads to savings in total energy use and energy-related 

carbon emissions in a cost-effective manner. Based on the average annual new 

construction in the state from 2003 to 2007 and a 10-year study period, adopting the LEC 

design would be even more beneficial for the state than adopting ASHRAE 90.1-2007, 

with savings of 99.4 GWh (339.4 GBtu), $9.8 million of energy costs, 58 411 metric tons 

of carbon emissions, and $2.4 million of life-cycle costs for one year’s worth of 

commercial building construction. 

35
 
Alaska 

36 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7 

Colorado 

Colorado 

Colorado was selected for this study for four reasons. First, Colorado is one of the three 

states with a current state energy code based on ASHRAE 90.1-2001 requirements. 

Second, the state is comparable in new construction volume to several other states 

selected for this study, which allows for comparisons across states. Third, the state 

represents the Rocky Mountain region of the U.S. and a variety of climate zones. Finally, 

Colorado has as least one jurisdiction that has adopted an energy standard edition that is 

more stringent than has been adopted by the state. 

Table 7-1 provides an overview of Colorado’s simulated energy use keyed to building 

types and energy standard editions. Average energy use varies across building types and 

building designs. The 8-story office building uses the least amount of energy at 80 

kWh/m2 to 113 kWh/m2 (25 kBtu/ft2 to 36 kBtu/ft2

) annually. The high school uses the 

greatest amount of energy at 203 kWh/m2 to 228 kWh/m2 (65 kBtu/ft2 to 72 kBtu/ ft2

) 

annually. 

Table 7-1 Average Annual Energy Use by Building Type and Energy Code, 

Colorado 

Building 

Type 

Energy Code 

2001 

kWh/m2 kBtu/ft2 

2004 

kWh/m2 kBtu/ft2 

2007 

kWh/m2 kBtu/ft2 

LEC 

kWh/m2 kBtu/ft2 

APART04 

APART06 

163 52 

160 51 

145 46 

141 45 

139 44 

136 43 

124 39 

121 38 

DORMI04 

DORMI06 

128 41 

175 56 

114 36 

156 50 

108 34 

153 49 

93 30 

136 43 

HOTEL15 158 50 142 45 149 47 130 41 

HIGHS02 228 72 224 71 216 69 203 65 

OFFIC03 

OFFIC08 

OFFIC16 

120 38 

113 36 

149 47 

112 35 

103 33 

139 44 

105 33 

99 31 

148 47 

84 27 

80 25 

124 39 

RETAIL1 145 46 134 42 119 38 102 32 

RSTRNT1 201 64 185 59 161 51 118 37 

The detailed analysis for this state reports the changes in energy use, energy costs, 

energy-related carbon emissions, and life-cycle costs from adoption of increasingly 

stringent energy codes. The results are reported in terms of average percentage savings on 

a statewide and city-by-city basis and as total savings on a statewide basis. 

37
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Colorado 

7.1 Percentage Savings 

Changes in percentage terms allow for direct comparisons across building types and 

locations within a state. This section discusses the average percentage changes from 

investing in more energy efficient designs for the state of Colorado. 

7.1.1 Energy Use 

Table 7-2 shows that the average percentage changes in energy use from adopting the 

ASHRAE 90.1-2004 design relative to ASHRAE 90.1-2001 range from -1.4 % to -9.1 % 

depending on the building type, with an overall average of -6.9 %. The average 

percentage change in energy use from constructing buildings using ASHRAE 90.1-2007 

requirements ranges from 0.3 % to -18.6 %, with an overall average of -10.4 %. 

Table 7-2 Average Percentage Change in Energy Use from Adoption of Newer 

Codes, Colorado 

Building Energy Code 

Type 2004 2007 LEC 

APART04 -8.8 -12.7 -21.9 

APART06 -9.1 -12.4 -22.5 

DORMI04 -8.3 -13.4 -24.9 

DORMI06 -9.0 -10.6 -20.7 

HOTEL15 -8.3 -3.4 -16.0 

HIGHS02 -1.4 -5.0 -10.6 

OFFIC03 -5.6 -11.3 -29.3 

OFFIC08 -7.5 -10.7 -28.3 

OFFIC16 -5.3 0.3 -15.7 

RETAIL1 -6.5 -17.1 -28.4 

RSTRNT1 -6.4 -18.6 -40.2 

Average -6.9 -10.4 -23.5 

For the high-rise, 100 % glazed buildings (16-story office building and 15-story hotel), 

ASHRAE 90.1-2004 is actually more energy efficient than ASHRAE 90.1-2007 because 

the maximum allowable window SHGC in Zone 5 and Zone 6 is increased from ASHRAE 

90.1-2004 to ASHRAE 90.1-2007 for buildings with fenestration accounting for greater 

than 40 % of total wall surface area. The 100 % glazing amplifies the impact of this 

requirement relaxation enough to overwhelm the energy efficiency gains obtained from 

other measures, such as increased insulation R-values. 

The LEC design realizes the greatest percentage change in energy use relative to 

ASHRAE 90.1-2001, with a range of -10.6 % to -40.2 % and an overall average 

of -23.5 %. Similar to the ASHRAE 90.1-2007 design, smaller reductions in energy use 

for the LEC design occur in the buildings with the greatest window-to-wall ratios. The 

smallest percentage reduction is realized by the high school because of its occupancy 

pattern. Schools are used primarily during the school year with minimal use during the 

38
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Colorado 

summer. Since some of the additional energy efficiency measures (daylighting and 

overhangs) adopted in the LEC design reduce solar heat gains, cooling loads are 

decreased while heating loads are increased. The increase in heating loads is greater than 

the reduction in cooling loads because the building has a low occupancy during the 

warmest months of the year and the Colorado climate requires significant heating during 

the coldest months. 

7.1.2 Energy Costs 

Table 7-3 shows a significant variation in the average change in energy costs over 10 

years of operation from adopting the ASHRAE 90.1-2004 design relative to ASHRAE 

90.1-2001, ranging from -6.3 % to -19.8 % depending on the building type, with an 

overall average of -14.1 %. The average change in energy costs from constructing 

buildings using ASHRAE 90.1-2007 requirements ranges from -2.4 % to -22.0 %, with an 

overall average of -15.2 %. As with energy use savings, adopting ASHRAE 90.1-2004 

results in greater reductions in energy costs than adopting ASHRAE 90.1-2007 for the two 

high rise buildings (16-story office building and 15-story hotel) because of the 100 % 

glazing in the buildings and the relaxed window SHGC requirements. 

Table 7-3 Average Percentage Change in Energy Costs, 10-Year, Colorado 

Building Energy Code 

Type 2004 2007 LEC 

APART04 -19.6 -22.0 -36.2 

APART06 -19.8 -21.7 -37.7 

DORMI04 -19.5 -21.8 -36.6 

DORMI06 -19.7 -20.6 -36.0 

HOTEL15 -18.4 -12.8 -28.8 

HIGHS02 -6.3 -8.8 -23.1 

OFFIC03 -8.8 -10.9 -32.1 

OFFIC08 -9.7 -10.6 -29.7 

OFFIC16 -9.1 -2.4 -21.2 

RETAIL1 -11.7 -17.3 -32.0 

RSTRNT1 -12.5 -18.8 -46.3 

Average -14.1 -15.2 -32.7 

The LEC design realizes the greatest percentage changes in energy costs, with the 

average reduction by building type ranging from -23.1 % to -46.3 % and an overall 

average of -32.7 %. The reductions in energy costs are greater than the reductions in 

energy use because the adopted energy efficiency measures decrease electricity 

consumption by a greater percentage than natural gas consumption. The greater relative 

reduction in electricity consumption further decreases energy costs because natural gas is 

cheaper per unit of energy than electricity in Colorado. 

39
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Colorado 

7.1.3 Energy-related Carbon Emissions 

Table 7-4 shows significant changes in average energy-related carbon emissions for 

ASHRAE 90.1-2004 for all building types, ranging from -7.0 % to -21.1 % with an overall 

average of -15.0 %. The average change in carbon emissions from constructing buildings 

using ASHRAE 90.1-2007 requirements is -15.8 % overall with the average change in 

carbon emissions varying across building types from -2.7 % to -23.1 %. The LEC design 

leads to the greatest average percentage changes in carbon emissions, ranging 

from -21.7 % to -47.0 % depending on the building type with an overall average 

of -33.8 % across all building types. 

Table 7-4 Average Percentage Change in Energy-related Carbon Emissions, 10­

Year, Colorado 

Building Energy Code 

Type 2004 2007 LEC 

APART04 -21.0 -23.1 -37.9 

APART06 -21.1 -22.8 -39.5 

DORMI04 -20.8 -22.8 -37.9 

DORMI06 -21.0 -21.8 -37.9 

HOTEL15 -19.6 -13.9 -30.3 

HIGHS02 -7.0 -9.3 -25.0 

OFFIC03 -9.2 -10.9 -32.4 

OFFIC08 -9.9 -10.6 -29.9 

OFFIC16 -9.5 -2.7 -21.7 

RETAIL1 -12.3 -17.3 -32.4 

RSTRNT1 -13.2 -18.8 -47.0 

Average -15.0 -15.8 -33.8 

As would be expected, a more energy efficient building design results in greater 

reductions in carbon emissions. However, the percentage reduction in carbon emissions is 

greater than the percentage reduction in energy use because the percentage reduction in 

electricity consumption is greater than the reduction in natural gas consumption. Since 

electricity production in Colorado generates greater emissions per unit of energy 

consumed than natural gas, the greater relative reduction in electricity leads to a greater 

reduction in carbon emissions. 

7.1.4 Life-Cycle Costs 

The most cost-effective building design for each building type is bolded in Table 7-5. 

The ASHRAE 90.1-2004, ASHRAE 90.1-2007, and LEC designs realize the lowest lifecycle costs for one, five, and five building types, respectively. Both ASHRAE 90.1-2004 

and ASHRAE 90.1-2007 realize lower life-cycle costs than ASHRAE 90.1-2001 for all 11 

building types. The LEC design results in significant reductions in life-cycle costs for 10 

of 11 building types. The change in life-cycle costs for the LEC design ranges 

from -7.4 % to 0.1 %. Based on the overall average change of -2.8 % in life-cycle costs, 

40
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Colorado 

the LEC design is likely to be cost-effective for the state to adopt as its state energy code 

for commercial buildings. 

Table 7-5 Average Percentage Change in Life-Cycle Costs, 10-Year, Colorado 

Building Energy Code 

Type 2004 2007 LEC 

APART04 -1.6 -1.9 -1.2 

APART06 -1.5 -1.8 -1.2 

DORMI04 -2.4 -2.9 -4.2 

DORMI06 -2.0 -2.1 -1.8 

HOTEL15 -2.1 -1.6 -1.1 

HIGHS02 -0.8 -1.1 -1.9 

OFFIC03 -2.3 -2.6 -5.5 

OFFIC08 -2.3 -2.6 -5.1 

OFFIC16 -1.0 -0.3 0.1 

RETAIL1 -2.1 -2.9 -2.0 

RSTRNT1 -2.5 -4.5 -7.4 

Average -1.9 -2.2 -2.8 

7.1.5 City Comparisons 

Simulations are run for 6 cities located in Colorado: Boulder, Colorado Springs, Grand 

Junction, and Pueblo in Climate Zone 5 and Alamosa and Eagle in Climate Zone 6. The 

results vary across cities within the state for several reasons. There are no significant 

population centers in Zone 4 or Zone 7 in the state of Colorado. First, the cities selected 

for the state cover two climate zones. The ASHRAE 90.1 building design requirements 

vary across climate zones and will impact the relative energy efficiency of the building. 

Second, cities within the same climate zone still have some variation in the local climate, 

which can lead to variation in energy consumption. Third, construction material and labor 

costs vary by locality. Finally, Grand Junction has adopted a stricter building energy code 

than has the state. 

As can be seen in Table 7-6, the average percentage reduction in energy use for all 

building types from adopting newer energy standard editions is generally greater for the 

cities located in Zone 5. For the LEC design, Zone 5 excluding Grand Junction realizes 

an average change in energy use of -25.8 % compared to -22.5 % for Zone 6. Grand 

Junction realizes much lower reductions in energy use for the ASHRAE 90.1-2007 and 

LEC designs because it has already adopted ASHRAE 90.1-2004 as its jurisdictional 

energy code. 

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Colorado 

Table 7-6 Average Percentage Change in Energy Use from Adoption of Newer 

Codes by City, Colorado 

Cities Zone Energy Code 

2004 2007 LEC 

Boulder 5B -9.4 -12.5 -25.5 

Colorado Springs 5B -9.2 -12.4 -24.9 

Grand Junction 5B 0.0 -3.2 -17.9 

Pueblo 5B -10.5 -13.2 -27.3 

Alamosa 6B -6.6 -11.0 -23.1 

Eagle 6B -5.9 -10.3 -22.2 

Average -6.9 -10.4 -23.5 

The variations in energy cost changes across cities are a result of two factors, the size of 

the reductions in energy use and the fuel source of the reduction. Table 7-7 shows that the 

average reduction in energy costs for all building types is similar across both Zone 5 and 

Zone 6 for both ASHRAE 90.1-2004 and ASHRAE 90.1-2007 when Grand Junction is 

excluded from the analysis. The LEC design realizes nearly twice the percentage 

reduction in energy costs than ASHRAE 90.1-2007, with Zone 5 cities excluding Grand 

Junction realizing an average change in energy costs of -35.7 % compared to -33.2 % for 

Zone 6. The reductions in energy costs are significantly greater than the reductions in 

energy use because the percentage reduction in electricity consumption is greater than the 

reduction in natural gas consumption. Since Grand Junction has already adopted 

ASHRAE 90.1-2004, it realizes much smaller changes in energy costs for the ASHRAE 

90.1-2007 and LEC designs. 

Table 7-7 Average Percentage Change in Energy Costs by City, 10-Year, Colorado 

Cities Zone Energy Code 

2004 2007 LEC 

Boulder 5B -16.8 -17.6 -35.6 

Colorado Springs 5B -16.9 -17.8 -35.4 

Grand Junction 5B 0.0 -1.1 -22.6 

Pueblo 5B -16.9 -17.7 -36.1 

Alamosa 6B -17.3 -18.9 -33.5 

Eagle 6B -16.7 -18.3 -32.9 

Average -14.1 -15.2 -32.7 

Table 7-8 reports changes in energy-related carbon emissions by city for the state. For all 

cities, the more energy efficient building designs result in greater reductions in carbon 

emissions. As with energy use, the cities in Zone 6 realize slightly lower average 

emission reductions than the cities in Zone 5 (excluding Grand Junction) for all building 

42
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Colorado 

designs. For both climate zones, adopting the ASHRAE 90.1-2007 and ASHRAE 

90.1-2004 designs would decrease energy-related carbon emissions on average. The LEC 

design realizes the greatest percentage reductions in carbon emissions, with the average 

percentage reduction ranging from -23.8 % to -37.1 % depending on the location. 

Table 7-8 Average Percentage Change in Carbon Emissions by City, 10-Year, 

Colorado 

Cities Zone Energy Code 

2004 2007 LEC 

Boulder 5B -17.0 -18.0 -36.7 

Colorado Springs 5B -17.1 -18.1 -36.6 

Grand Junction 5B 0.0 -1.3 -23.8 

Pueblo 5B -16.9 -17.9 -37.1 

Alamosa 6B -17.9 -19.5 -34.7 

Eagle 6B -17.3 -19.0 -34.2 

Average -15.0 -15.8 -33.8 

The data reported in Table 7-9 show that, over a 10-year period, the LEC design results in 

the lowest average life-cycle costs for all cities in both Zone 5 and Zone 6. Reductions in 

life-cycle costs are similar across all cities in the state except for Grand Junction, which 

realizes much smaller cost reductions because the city has adopted ASHRAE 90.1-2004. 

Life-cycle costs are reduced by adopting ASHRAE 90.1-2004 or ASHRAE 90.1-2007 

relative to ASHRAE 90.1-2001 for all cities, on average. 

Table 7-9 Average Percentage Change in Life-Cycle Costs by City, 10-Year, 

Colorado 

Cities Zone
 Energy Code 

2004 2007 LEC
 

Boulder 5B -2.1 -2.4 -2.9 

Colorado Springs 5B -2.1 -2.4 -2.9 

Grand Junction 5B 0.0 -0.4 -1.7 

Pueblo 5B -2.2 -2.6 -3.6 

Alamosa 6B -2.5 -2.8 -3.1 

Eagle 6B -2.4 -2.7 -2.9 

Average -1.9 -2.2 -2.8 

7.2 Total Savings 

How much can Colorado save, in terms of energy use, energy costs, and carbon 

emissions, from adopting a more stringent state energy code for commercial buildings? 

What are the life-cycle costs associated with the new energy code adoption? To answer 

43
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Colorado 

these questions, it is first necessary to estimate savings per unit of floor area for each 

building type in the state. 

7.2.1 Energy Use 

Table 7-10 reports the average per unit change in annual energy use by building type and 

building design in the state.17 The reduction per m2 (ft2

) is multiplied by the estimated 

annual m2 (ft2) of new construction of each building type. Table 7-11 reports the 

estimated average annual floor area of new construction and the total annual reduction in 

energy use for each building type. The weightings within a category (e.g. small, medium, 

and large office buildings) are based on the national average percentage of new building 

construction for the category that is represented by each subcategory.18 

Table 7-10 Average Per Unit Change in Annual Energy Use, Colorado 

Building Energy Code 

Type 2004 

kWh/m2 kBtu/ft2 

2007 

kWh/m2 kBtu/ft2 

LEC 

kWh/m2 kBtu/ft2 

APART04 -14.1 -4.5 -20.4 -6.5 -35.0 -11.1 

APART06 -14.3 -4.5 -19.5 -6.2 -35.1 -11.1 

DORMI04 -10.4 -3.3 -16.7 -5.3 -31.1 -9.9 

DORMI06 -15.7 -5.0 -18.5 -5.9 -35.6 -11.3 

HOTEL15 -13.0 -4.1 -5.5 -1.7 -24.8 -7.9 

HIGHS02 -6.7 -2.1 -13.4 -4.3 -34.7 -11.0 

OFFIC03 -3.0 -1.0 -11.1 -3.5 -23.8 -7.5 

OFFIC08 -8.4 -2.7 -12.0 -3.8 -31.5 -10.0 

OFFIC16 -7.8 -2.5 0.4 0.1 -23.1 -7.3 

RETAIL1 -9.4 -3.0 -24.6 -7.8 -40.8 -13.0 

RSTRNT1 -12.7 -4.0 -37.1 -11.8 -79.7 -25.3 

The total annual reduction in energy use ranges widely across building designs, but the 

ASHRAE 90.1-2004, ASHRAE 90.1-2007, and LEC designs all decrease overall energy 

use across the state. Adopting ASHRAE 90.1-2004 results in annual reductions of 18.7 

GWh (63.7 GBtu) while adopting ASHRAE 90.1-2007 saves 32.8 GWh (112.0 GBtu) 

annually. The adoption of the LEC design as the state’s energy code would save energy 

for all building types and 67.2 GWh (229.5 GBtu) of total energy use annually for one 

year’s worth of new construction for these building types. 

17 A simple average for a state is used because no data for a weighted average is available regarding the
 

amount of new construction on a city-by-city basis.
 

18 State-level subcategory data are not available.
 

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Colorado 

Table 7-11 Statewide Change in Annual Energy Use for One Year of Construction, 

Colorado 

Building 

Type 

Subcat. 

Weight. m 2 

(1000s) 

ft2 

(1000s) 

Energy Code 

2004 

kWh kBtu 

2007 

kWh kBtu 

LEC 

kWh kBtu 

APART04 

APART06 

44.9 % 

55.1 % 

183 

224 

1967 

2410 

-2 581 945 -8 815 869 

-3 204 843 -10 942 711 

-3 724 753 -12 717 908 

-4 358 644 -14 882 284 

-6 401 934 -21 858 955 

-7 860 201 -26 838 104 

HOTEL15 100.0 % 199 2147 -2 601 371 -8 882 201 -1 096 565 -3 744 144 -4 942 031 -16 874 218 

HIGHS02 100.0 % 331 3561 -996 825 -3 403 588 -3 663 683 -12 509 390 -7 870 278 -26 872 513 

OFFIC03 

OFFIC08 

OFFIC16 

37.4 % 

40.4 % 

22.2 % 

162 

174 

96 

1739 

1875 

1032 

-1 082 947 -3 697 645 

-1 465 291 -5 003 132 

-747 292 -2 551 575 

-2 169 553 -7 407 787 

-2 089 987 -7 136 114 

40 723 139 045 

-5 608 663 -19 150 389 

-5 491 202 -18 749 324 

-2 210 409 -7 547 288 

RETAIL1 100.0 % 579 6235 -5 465 300 -18 660 885 -14 251 754 -48 661 618 -23 662 413 -80 793 652 

RSTRNT1 100.0 % 40 428 -506 957 -1 730 969 -1 477 307 -5 044 160 -3 172 792 -10 833 277 

Total 1988 21 394 -18 652 769 -63 688 575 -32 791 523 -111 964 360 -67 219 923 -229 517 720 

Note: Dormitories are excluded because no floor area category is reported in the construction data. 

Assuming that the buildings considered in this study, which represent 60.4 % of all new 

commercial floor space in the state, are generally representative of the entire new 

commercial building stock in the state, the results for the LEC design can be extrapolated 

to estimate the total statewide energy use savings to be 111.3 GWh (380.0 GBtu) 

annually. Annual savings of 111.3 GWh (380.0 GBtu) implies 1113 GWh (3800.0 GBtu) 

in energy savings over the 10-year study period. In comparison, ASHRAE 90.1-2004 and 

ASHRAE 90.1-2007 would save 30.9 GWh and 54.3 GWh annually, or 308.8 GWh and 

542.9 GWh over the 10-year study period, respectively. 

The statewide change in energy use varies across the 9 building types with reported floor 

area data within a building design. Building types that represent a greater amount of new 

floor area realize the largest total changes in energy use. The building types that have the 

greatest percentage reduction in energy use are not always the same buildings that lead to 

the greatest total reductions for the state. For example, the building types that lead to the 

greatest estimated reductions in energy use for the LEC design -- retail stores, high 

schools, and high-rise apartment buildings -- rank 3rd, 11th , and 6th in percentage 

reduction, respectively, among the 11 building types, as reported in Table 7-2. The two 

high-rise buildings with 100 % window glazing realize the smallest statewide reductions 

in energy use for ASHRAE 90.1-2004 and ASHRAE 90.1-2007 due to the consolidation of 

climate zones from ASHRAE 90.1-2001 to ASHRAE 90.1-2004, which relaxes the 

window U-factor requirements. ASHRAE 90.1-2007 results in a small increase in energy 

use for 16-story office buildings due to relaxation of the window SHGC requirements 

relative to ASHRAE 90.1-2004. 

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Colorado 

7.2.2 Energy Costs 

Table 7-12 reports the average per unit change in energy costs by building type and 

building design. Energy costs are calculated using the annual energy use, energy cost 

rates, and energy price escalation rates as defined in Section 3.2. 

Table 7-12 Average Per Unit Change in Energy Costs, 10-Year, Colorado 

Building Energy Code 

Type 2004 

$/m2 $/ft2 

2007 

$/m2 $/ft2 

LEC 

$/m2 $/ft2 

APART04 -$15.02 -$1.40 -$16.75 -$1.56 -$27.18 -$2.53 

APART06 -$15.15 -$1.41 -$16.53 -$1.54 -$28.24 -$2.62 

DORMI04 -$12.36 -$1.15 -$13.75 -$1.28 -$22.76 -$2.11 

DORMI06 -$16.54 -$1.54 -$17.28 -$1.60 -$29.72 -$2.76 

HOTEL15 -$14.23 -$1.32 -$10.09 -$0.94 -$21.82 -$2.03 

HIGHS02 -$5.75 -$0.53 -$7.96 -$0.74 -$20.85 -$1.94 

OFFIC03 -$5.87 -$0.55 -$7.24 -$0.67 -$21.21 -$1.97 

OFFIC08 -$6.45 -$0.60 -$7.04 -$0.65 -$19.61 -$1.82 

OFFIC16 -$7.44 -$0.69 -$2.04 -$0.19 -$17.02 -$1.58 

RETAIL1 -$8.50 -$0.79 -$12.52 -$1.16 -$23.00 -$2.14 

RSTRNT1 -$12.57 -$1.17 -$18.75 -$1.74 -$45.76 -$4.25 

Table 7-13 reports the statewide changes in total energy costs by building type and 

building design, which account for one year’s worth of new construction evaluated over 

10 years of building operation. Overall, reductions in energy costs are greater for the 

more energy efficient building designs: $18.5 million, $21.1 million, and $43.9 million 

for adopting ASHRAE 90.1-2004, ASHRAE 90.1-2007, and LEC, respectively. All 

building types realize energy cost savings for all three of these building designs. 

Assuming that the buildings considered in this study are generally representative of the 

entire new commercial building stock in the state, the results for ASHRAE 90.1-2004, 

ASHRAE 90.1-2007, and LEC can be extrapolated to estimate the total statewide energy 

cost savings of $30.6 million, $35.0 million, and $72.7 million over the 10-year study 

period, respectively. 

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Colorado 

Table 7-13 Statewide Change in Energy Costs for One Year of Construction, 10­

Year, Colorado 

Building Subcategory m 2 ft2 Energy Code 

Type Weighting (1000s) (1000s) 2004 2007 LEC 

APART04 44.9 % 183 1967 -$2 744 758 -$3 060 808 -$4 967 750
 

APART06 55.1 % 224 2410 -$3 391 792 -$3 700 430 -$6 321 780
 

HOTEL15 100.0 % 199 2147 -$2 839 304 -$2 012 375 -$4 352 321 

HIGHS02 100.0 % 331 2403 -$1 284 340 -$1 776 264 -$4 653 715 

OFFIC03 37.4 % 162 1739 -$948 189 -$1 169 098 -$3 426 305 

OFFIC08 40.4 % 174 1875 -$1 122 606 -$1 226 719 -$3 415 693 

OFFIC16 22.2 % 96 1032 -$712 783 -$195 861 -$1 630 928 

RETAIL1 100.0 % 579 6235 -$4 921 446 -$7 250 291 -$13 324 499 

RSTRNT1 100.0 % 40 428 -$500 117 -$746 212 -$1 821 095 

Total 1988 20 235 -$18 465 334 -$21 138 058 -$43 914 086 

Note: Dormitories are excluded because no floor area category is reported in the construction data. 

7.2.3 Energy-related Carbon Emissions 

Table 7-14 reports the average reduction in energy-related carbon emissions over 10 

years, per m 2 (ft2

), by building type and building design. The carbon emissions estimation 

approach is defined in Section 5.3. 

Table 7-14 Average Per Unit Change in Carbon Emissions, 10-Year, Colorado 

Building Energy Code 

Type 2004 

kg/m2 lb/ft2 

2007 

kg/m2 lb/ft2 

LEC 

kg/m2 lb/ft2 

APART04 -239.5 -49.1 -263.1 -53.9 -425.3 -87.1 

APART06 -241.6 -49.5 -260.3 -53.3 -443.0 -90.7 

DORMI04 -198.3 -40.6 -216.0 -44.2 -354.7 -72.6 

DORMI06 -263.8 -54.0 -273.6 -56.0 -467.4 -95.7 

HOTEL15 -227.3 -46.6 -164.4 -33.7 -344.3 -70.5 

HIGHS02 -93.8 -19.2 -123.8 -25.4 -328.9 -67.4 

OFFIC03 -92.6 -19.0 -109.7 -22.5 -325.6 -66.7 

OFFIC08 -100.8 -20.6 -107.7 -22.1 -301.5 -61.7 

OFFIC16 -117.9 -24.2 -34.6 -7.1 -265.3 -54.3 

RETAIL1 -134.3 -27.5 -188.5 -38.6 -350.3 -71.7 

RSTRNT1 -199.6 -40.9 -282.2 -57.8 -698.1 -143.0 

Table 7-15 applies the Table 7-14 results to one year’s worth of new building 

construction in the state to estimate statewide reduction in carbon emissions from 

adoption of more energy efficient codes. The total reduction in carbon emissions ranges 

widely across building designs, but the ASHRAE 90.1-2004, ASHRAE 90.1-2007, and 

LEC designs all decrease carbon emissions. The adoption of ASHRAE 90.1-2004 results 

in savings of 293 683 metric tons while adopting ASHRAE 90.1-2007 saves 327 025 

metric tons over a 10-year study period. The adoption of the LEC design as the state’s 

47
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Colorado 

energy code decreases carbon emissions by 680 244 metric tons over the 10-year study 

period for one year’s worth of new commercial construction for these building types. 

Assuming that the buildings considered in this study are generally representative of the 

entire new building stock in the state, the results for ASHRAE 90.1-2004, ASHRAE 

90.1-2007, and LEC can be extrapolated to estimate statewide reductions in carbon 

emissions of 486 230 tons, 541 432 tons, and 1.1 million tons over the 10-year study 

period, respectively. 

Table 7-15 Statewide Change in Total Carbon Emissions for One Year of 

Construction, 10-Year, Colorado – Metric Tons 

Building Subcategory m 2 ft2 Energy Code 

Type Weighting (1000s) (1000s) 2004 2007 LEC 

APART04 44.9 % 183 1967 -43 777 -48 088 -77 740
 

APART06 55.1 % 224 2410 -54 085 -58 262 -99 177
 

HOTEL15 100.0 % 199 2147 -45 345 -32 784 -68 685 

HIGHS02 100.0 % 331 2403 -20 947 -27 639 -73 418 

OFFIC03 37.4 % 162 1739 -14 958 -17 723 -52 588 

OFFIC08 40.4 % 174 1875 -17 552 -18 757 -52 512 

OFFIC16 22.2 % 96 1032 -11 302 -3 318 -25 429 

RETAIL1 100.0 % 579 6235 -77 772 -109 222 -202 911 

RSTRNT1 100.0 % 40 428 -7 945 -11 232 -27 785 

Total 1988 20 235 -293 683 -327 025 -680 244 

Note: Dormitories are excluded because no floor area category is reported in the 

construction data. 

7.2.4 Life-Cycle Costs 

Table 7-16 reports the average change in life-cycle cost over 10 years, per m2 (ft2), by 

building type and building design. As discussed in Section 5.2, life-cycle costs include 

construction costs, maintenance, repair, and replacement costs, energy costs, and residual 

values. 

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Colorado 

Table 7-16 Average Per Unit Change in Life-Cycle Costs, 10-Year, Colorado
 

Building Energy Code 

Type 2004 

$/m2 $/ft2 

2007 

$/m2 $/ft2 

LEC 

$/m2 $/ft2 

APART04 -$15.22 -$1.41 -$18.23 -$1.69 -$12.01 -$1.12 

APART06 -$15.11 -$1.40 -$17.33 -$1.61 -$11.56 -$1.07 

DORMI04 -$22.39 -$2.08 -$26.87 -$2.50 -$39.72 -$3.69 

DORMI06 -$19.81 -$1.84 -$20.91 -$1.94 -$18.12 -$1.68 

HOTEL15 -$20.06 -$1.86 -$15.60 -$1.45 -$10.73 -$1.00 

HIGHS02 -$6.15 -$0.57 -$8.93 -$0.83 -$15.15 -$1.41 

OFFIC03 -$18.67 -$1.73 -$20.70 -$1.92 -$44.11 -$4.10 

OFFIC08 -$19.31 -$1.79 -$21.44 -$1.99 -$42.52 -$3.95 

OFFIC16 -$7.59 -$0.70 -$2.43 -$0.23 $1.10 $0.10 

RETAIL1 -$13.66 -$1.27 -$18.25 -$1.70 -$12.78 -$1.19 

RSTRNT1 -$32.22 -$2.99 -$59.08 -$5.49 -$98.13 -$9.12 

Table 7-17 applies the Table 7-16 results to one year’s worth of new building 

construction in the state to estimate statewide changes in life-cycle costs from adoption of 

more energy-efficient codes. Total reductions in life-cycle costs over the 10-year study 

period vary across building designs. ASHRAE 90.1-2004 and ASHRAE 90.1-2007 result 

in a decrease in life-cycle costs for all 9 building types while the LEC design decreases 

life-cycle costs for 8 of 9 building types. The 16-story office building realizes the 

smallest total reductions in life-cycle costs for all three alternative building designs and, 

for the LEC design, realizes increases in life-cycle costs. ASHRAE 90.1-2007 results in 

greater total reductions in life-cycle costs than ASHRAE 90.1-2004 for the building types 

considered in this study ($32.5 million versus $27.8 million). The LEC design leads to 

the greatest total reductions in life-cycle costs of $36.0 million. 

Assuming that the buildings considered in this study are generally representative of the 

entire new commercial building stock in the state, the results for the ASHRAE 90.1-2004, 

ASHRAE 90.1-2007, and LEC designs can be extrapolated to estimate statewide changes 

in life-cycle costs of $46.1 million, $53.9 million, and $59.7 million over the 10-year 

study period, respectively. 

49
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Colorado 

Table 7-17 Statewide Change in Life-Cycle Costs for One Year of Construction, 

10-Year, Colorado 

Building 

Type 

Subcategory 

Weighting 

m 2 

(1000s) 

ft2 

(1000s) 

Energy Code 

2004 2007 LEC 

APART04 

APART06 

44.9 % 183 1967 -$2 780 914 -$3 331 475 -$2 195 187 

55.1 % 224 2410 -$3 381 651 -$3 878 490 -$2 586 926 

HOTEL15 100.0 % 199 2147 -$4 001 180 -$3 112 617 -$2 139 459 

HIGHS02 100.0 % 331 2403 -$1 373 361 -$1 992 603 -$3 382 270 

OFFIC03 

OFFIC08 

OFFIC16 

37.4 % 162 1739 -$3 015 796 -$3 342 811 -$7 123 855 

40.4 % 174 1875 -$3 363 646 -$3 733 863 -$7 405 617 

22.2 % 96 1032 -$727 029 -$232 930 $105 555 

RETAIL1 100.0 % 579 6235 -$7 915 065 -$10 570 652 -$7 401 280 

RSTRNT1 100.0 % 40 428 -$1 282 163 -$2 351 325 -$3 905 355 

Total 1988 20 235 -$27 840 805 -$32 546 766 -$36 034 394 

Note: Dormitories are excluded because no floor area category is reported in the construction data. 

7.3 State Summary 

Colorado is one of the few states that has adopted ASHRAE 90.1-2001 as its state energy 

code for commercial buildings, and represents the Rocky Mountain region of the United 

States. On average, adopting a newer edition of ASHRAE 90.1 leads to reductions in 

energy use, energy costs, and cradle-to-grave energy-related carbon emissions. However, 

adopting ASHRAE 90.1-2007 increases energy use for some location-building type 

combinations, particularly for 16-story office buildings. ASHRAE 90.1-2004 condenses 

the 26 climate zones defined in ASHRAE 90.1-1999/2001 into 8 climate zones. As a 

result, some of the building envelope requirements (window U-factors and insulation Rvalues) are slightly less stringent for some locations. Additionally, ASHRAE 90.1-2007 

further relaxes the window SHGC requirements for some locations. 

Colorado is one of the few states that have at least one city that has adopted a more 

stringent energy standard edition than the state. Grand Junction has adopted ASHRAE 

90.1-2004, which tempers the reductions in energy use, energy costs, and energy-related 

carbon emissions from the adoption of either the ASHRAE 90.1-2007 or LEC designs. 

Despite these factors, the adoption of more efficient building design requirements leads 

to savings in energy use and life-cycle costs. Based on the average annual new 

construction in the state from 2003 to 2007 and a 10-year study period, adopting 

ASHRAE 90.1-2007 as the state’s energy code for commercial buildings would lead to 

energy use savings of 543 GWh, energy cost savings of $35.0 million, life-cycle cost 

savings of $53.9 million, and 541 432 metric tons of carbon emissions reductions for one 

year’s worth of commercial building construction. Adopting the LEC design would be 

even more beneficial for the state with savings of 1112.9 GWh (3800.0 GBtu), 

50
 
 

 

Colorado 

$72.7 million in energy costs, 1.1 million metric tons of carbon emissions, and life-cycle 

cost savings of $59.7 million. 

51
 
Colorado 

52 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8 

Florida 

Florida 

Florida was selected for this study for three reasons. First, the state represents the 

warmest and most humid climate zones in the United States. Second, the state had more 

new building construction than any other state from 2003 to 2007. Third, the state 

represents the southern area of the United States. Florida is one of four states in this study 

that have adopted ASHRAE 90.1-2007 as its state energy code for commercial buildings. 

Table 8-1 provides an overview of Florida’s simulated energy use keyed to building type 

and energy standard edition. Average energy use varies across building types and 

building designs. The 4-story dormitory uses the least amount of energy at 79 kWh/m2 to 

95 kWh/m2 (25 kBtu/ft2 to 30 kBtu/ft2) annually. The restaurant uses the greatest amount 

of energy at 108 kWh/m2 to 155 kWh/m2 (34 kBtu/ft2 to 49 kBtu/ft2) annually. 

Table 8-1 Average Annual Energy Use by Building Type and Energy Code, Florida 

Building 

Type 

Energy Code 

2007 

kWh/m2 kBtu/ft2 

LEC 

kWh/m2 kBtu/ft2 

APART04 

APART06 

129 41 

130 41 

108 34 

107 34 

DORMI04 

DORMI06 

95 30 

139 44 

79 25 

114 36 

HOTEL15 109 35 91 29 

HIGHS02 126 40 99 31 

OFFIC03 

OFFIC08 

OFFIC16 

113 36 

109 35 

127 40 

86 27 

87 28 

105 33 

RETAIL1 114 36 93 29 

RSTRNT1 155 49 108 34 

The detailed analysis for this state reports changes in energy use, energy costs, energyrelated carbon emissions, and life-cycle costs from adoption of the LEC design beyond 

the current state energy code. The results are reported in terms of average percentage 

savings on a statewide and city-by-city basis and as total savings on a statewide basis. 

8.1 Percentage Savings 

Changes in percentage terms allow for direct comparisons across building types and 

locations within a state. This section discusses the average percentage changes from 

investing in the LEC design for the state of Florida. 

53
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Florida 

8.1.1 Statewide Building Comparison 

Table 8-2 shows the percentage change in energy use, energy costs, energy-related 

carbon emissions, and life-cycle costs for the LEC design relative to ASHRAE 90.1-2007. 

The LEC design realizes changes in energy use ranging from -16.6 % to -30.5 %, with an 

average of -19.8 %. The lowest reduction in energy use for the LEC design occurs in the 

4-story apartment building and hotel while the greatest reduction in energy use occurs in 

restaurants. 

Table 8-2 Average Percentage Change from Adoption of a Newer Code, 10-Year, 

Florida 

Building LEC 

Type Energy Use Energy Costs Carbon LCC 

APART04 -16.6 -17.7 -17.8 -0.3 

APART06 -17.5 -18.9 -19.0 -0.4 

DORMI04 -17.4 -18.4 -18.5 -2.1 

DORMI06 -18.4 -20.0 -20.1 -0.9 

HOTEL15 -16.7 -18.8 -19.0 -0.1 

HIGHS02 -21.2 -23.4 -23.7 -1.9 

OFFIC03 -24.0 -24.3 -24.3 -2.3 

OFFIC08 -20.1 -20.2 -20.2 -2.6 

OFFIC16 -17.6 -18.5 -18.5 -0.2 

RETAIL1 -17.9 -18.2 -18.2 -0.7 

RSTRNT1 -30.5 -31.5 -31.6 -5.3 

Average -19.8 -20.9 -21.0 -1.5 

The LEC design realizes average changes in energy costs over 10 years of building 

operation ranging from -17.7 % to -31.5 % depending on the building type, with an 

average of -20.9 % overall. The 4-story apartment building realizes the smallest average 

percentage reductions in energy costs while the restaurant realizes the greatest average 

reductions in energy use. The reductions in energy costs are nearly identical to the 

reductions in energy use because electricity accounts for 95 % of total energy use for the 

ASHRAE 90.1-2007 design. Therefore, any change in energy costs is driven by the 

change in use of a single fuel type, electricity. 

The LEC design leads to average percentage changes in energy-related carbon emissions 

ranging from -17.8 % to -31.6 %, depending on the building type, with an average 

of -21.0 % across all building types. As would be expected, a more energy efficient 

building design results in greater reductions in carbon emissions. Similar to energy costs, 

the percentage reduction in carbon emissions is nearly identical to the percentage 

reduction in energy use because electricity consumption accounts for 95 % of total 

energy use for the ASHRAE 90.1-2007 design, which minimizes any impacts from 

shifting of energy use between electricity and natural gas consumption. 

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Florida 

The LEC design results in average reductions in life-cycle costs for a 10-year study 

period for all 11 building types. The average percentage change in life-cycle costs for the 

LEC design ranges from -0.1 % to -5.3 %. The restaurant and 3- and 8-story office 

buildings realize the greatest average percentage reduction in life-cycle costs while the 

hotel and 16-story office building realize the smallest average percentage reduction in 

life-cycle costs. The LEC design is cost-effective for the state to adopt as its state energy 

code for commercial buildings. 

8.1.2 City Comparisons 

Simulations are run for 7 cities located in Florida: Key West and Miami in Climate 

Zone 1, and Daytona Beach, Jacksonville, Tallahassee, Tampa, and West Palm Beach in 

Zone 2A. The results vary across cities within the state for several reasons. First, the state 

is covered by two climate zones. The ASHRAE 90.1 building design requirements vary 

across climate zones and will impact the relative energy efficiency of the building. 

Second, cities within the same climate zone still have some variation in the local climate, 

which can lead to variation in energy consumption. Third, construction material and labor 

costs vary by locality. 

As can be seen in Table 8-3, the average reduction in energy use for all building types 

from adopting the LEC design is slightly greater for the cities located in Zone 1 than in 

Zone 2. For the LEC design, Zone 1 realizes an average change in energy use of -22.0 % 

compared to -21.1 % for Zone 2. The average percentage change in energy use varies 

minimally within Zone 2, -20.9 % to -21.2 %, because of climate variation within the 

subzone. The cities located furthest north in the state, Jacksonville and Tallahassee, 

realize the smallest reductions in energy use. 

Table 8-3 Average Percentage Change in Energy Use from Adoption of Newer 

Codes by City, 10-Year, Florida 

Cities Zone LEC 

Energy Use Energy Cost Carbon LCC 

Key West 1 -21.3 -21.3 -22.1 -2.1 

Miami 1 -21.2 -21.3 -22.0 -1.9 

Daytona Beach 2A -20.3 -21.4 -21.9 -1.4 

Jacksonville 2A -18.1 -20.4 -21.0 -1.1 

Tallahassee 2A -17.6 -20.5 -21.1 -1.1 

Tampa 2A -19.9 -20.8 -21.2 -1.5 

West Palm Beach 2A -20.3 -20.5 -20.9 -1.6 

Average -19.8 -20.9 -21.5 -1.5 

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Florida 

The average reduction in energy costs for all building types is relatively constant across 

cities throughout the state. For the LEC design, Zone 1 realizes an average change in 

energy costs of -21.3 % compared to -20.7 % for Zone 2. 

For all cities, the LEC design results in reductions in energy-related carbon emissions 

relative to ASHRAE 90.1-2007. There is minor variation across cities in the change in 

carbon emissions, -20.9 % versus -22.1 %, with Climate Zone 1 realizing slightly greater 

reductions. 

The LEC design results in average percentage reductions in life-cycle costs relative to 

ASHRAE 90.1-2007 across all cities in the state, ranging from 1.1 % to 2.1 %. These cost 

variations are probably a result of the variation in building envelope design requirements 

across climate zones combined with different local construction costs across the state. 

Cities located further north realize smaller percentage reductions in life-cycle costs. 

8.2 Total Savings 

How much can Florida save, in terms of energy use, energy costs, and carbon emissions, 

from adopting a more stringent state energy code for commercial buildings? What are the 

life-cycle costs associated with the new energy code adoption? To answer these 

questions, it is first necessary to estimate savings per unit of floor area for each building 

type in the state. 

8.2.1 Energy Use 

Table 8-4 reports the average per unit change in annual energy use by building type for 

the LEC design in the state.19 The reduction per m2 (ft2

) is multiplied by the estimated m2 

(ft2) of new construction of each building type. Table 8-5 reports the estimated average 

annual floor area of new construction and the total annual reduction in energy use for 

each building type. The weightings within a category (e.g. small, medium, and large 

office buildings) are based on the national average percentage of new building 

construction for the category that is represented by each subcategory.20 

19 A simple average for a state is used because no data for a weighted average is available regarding the 

amount of new construction on a city-by-city basis. 

20 State-level subcategory data are not available. 

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Florida 

Table 8-4 Average Per Unit Change in Annual Energy Use, Florida
 

Building Energy Code 

Type LEC 

kWh/m2 kBtu/ft2 

APART04 -21.4 -6.8 

APART06 -22.8 -7.2 

DORMI04 -16.6 -5.3 

DORMI06 -25.8 -8.2 

HIGHS02 -18.2 -5.8 

HOTEL15 -27.4 -8.7 

OFFIC03 -26.7 -8.5 

OFFIC08 -21.9 -6.9 

OFFIC16 -22.4 -7.1 

RETAIL1 -20.8 -6.6 

RSTRNT1 -47.3 -15.0 

The annual reduction in energy use ranges widely across building types, but the LEC 

design decreases overall energy use across the state relative to ASHRAE 90.1-2007. The 

adoption of the LEC design as the state’s energy code would save energy for all building 

types, and 246 GWh (841 GBtu) of total energy use annually for one year’s worth of new 

construction for these building types. Assuming that the buildings considered in this 

study, which represent 65.0 % of all new commercial floor space in the state, are 

generally representative of the entire new commercial building stock in the state, the 

results can be extrapolated to estimate total statewide savings to be 379 GWh 

(1294.2 GBtu) per year. These savings imply over 3790.5 GWh (12942.3 GBtu) in 

energy savings over the 10-year study period. 

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Florida 

Table 8-5 Statewide Change in Annual Energy Use for One Year of Construction, 

Florida 

Building Subcategory m 2 ft2 Energy Code 

Type Weighting (1000s) (1000s) LEC 

kWh kBtu 

APART04 44.9 % 1923 20 704 -41 125 439 -140 419 934
 

APART06 55.1 % 2356 25 359 -53 670 927 -183 255 624
 

HOTEL15 100.0 % 596 6414 -10 823 497 -36 956 072 

HIGHS02 100.0 % 1552 16 705 -41 416 445 -141 413 553 

OFFIC03 37.4 % 676 7277 -18 492 215 -63 140 373 

OFFIC08 40.4 % 729 7848 -15 950 755 -54 462 735 

OFFIC16 22.2 % 401 4318 -8 971 492 -30 632 532 

RETAIL1 100.0 % 2381 25 627 -49 516 636 -169 071 088 

RSTRNT1 100.0 % 136 1460 -6 413 952 -21 899 992 

Total 10 750 115 711 -246 381 359 -841 251 902 

Note: Dormitories are excluded because no floor area category is reported in the 

construction data. 

The reduction in energy use varies across the 9 building types with reported floor area 

data. The greatest reductions in energy use occur for 6-story apartment buildings 

followed by retail stores, high schools, and 4-story apartment buildings while the smallest 

reductions occur for restaurants and the high-rise buildings. Building types that represent 

a greater amount of new floor area tend to realize the largest changes in energy use. The 

amount of new floor area overwhelms the minimal variation in the percentage reduction 

in energy use. 

8.2.2 Energy Costs 

Table 8-6 reports the average per unit change in energy costs by building type. Energy 

costs are calculated using the annual energy use, state average energy cost rates, and 

regional energy price escalation rates as defined in Section 3.2. 

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Florida 

Table 8-6 Average Per Unit Change in Energy Costs, 10-Year, Florida
 

Building Energy Code 

Type LEC 

$/m2 $/ft2 

APART04 -$18.85 -$1.75 

APART06 -$20.25 -$1.88 

DORMI04 -$14.60 -$1.36 

DORMI06 -$22.97 -$2.13 

HIGHS02 -$16.63 -$1.55 

HOTEL15 -$24.03 -$2.23 

OFFIC03 -$23.50 -$2.18 

OFFIC08 -$18.64 -$1.73 

OFFIC16 -$19.69 -$1.83 

RETAIL1 -$17.79 -$1.65 

RSTRNT1 -$40.76 -$3.79 

Table 8-7 reports the statewide changes in total energy costs by building type, which 

account for one year’s worth of new construction evaluated over 10 years of building 

operation. Overall, the reduction in energy costs totals $216 million for adopting the LEC 

design relative to ASHRAE 90.1-2007. All building types realize energy cost savings for 

the LEC design. The greatest energy cost savings are realized by the apartment buildings, 

retail stores, and high schools. The smallest reductions in energy costs are realized by 

restaurants and 16-story office buildings. Assuming that the buildings considered in this 

study, which represent 65.0 % of all new floor space in the state, are generally 

representative of the entire new commercial building stock in the state, the results for the 

LEC design can be extrapolated to estimate the total statewide energy cost savings of 

$333 million over the 10-year study period. 

Table 8-7 Statewide Change in Energy Costs for One Year of Construction, 

10-Year, Florida 

Building Subcategory m 2 ft2 Energy Code
 

Type Weighting (1000s) (1000s) LEC
 

APART04 44.9 % 1923 20 704 -$36 256 290
 

APART06 55.1 % 2356 25 359 -$47 701 308
 

HOTEL15 100.0 % 596 6414 -$9 911 975 

HIGHS02 100.0 % 1552 16 705 -$37 299 219 

OFFIC03 37.4 % 676 7277 -$15 888 663 

OFFIC08 40.4 % 729 7848 -$13 590 986 

OFFIC16 22.2 % 401 4318 -$7 896 893 

RETAIL1 100 % 2381 25 627 -$42 351 551 

RSTRNT1 100 % 136 1460 -$5 527 562 

Total 10 750 115 711 -$216 424 446 

Note: Dormitories are excluded because no floor area category is 

reported in the construction data. 

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Florida 

8.2.3 Energy-related Carbon Emissions 

Table 8-8 reports the average energy-related reduction in carbon emissions over 10 years, 

per m 2 (ft2), by building type. The carbon emissions estimation approach is defined in 

Section 5.3. 

Table 8-8 Average Per Unit Change in Carbon Emissions, 10-Year, Florida 

Building Energy Code 

Type LEC 

kg/m2 lb/ft2 

APART04 -182.9 -37.5 

APART06 -196.6 -40.3 

DORMI04 -141.7 -29.0 

DORMI06 -223.2 -45.7 

HOTEL15 -161.9 -33.2 

HIGHS02 -233.7 -47.9 

OFFIC03 -227.5 -46.6 

OFFIC08 -180.4 -36.9 

OFFIC16 -191.0 -39.1 

RETAIL1 -172.2 -35.3 

RSTRNT1 -394.7 -80.8 

Table 8-9 applies the Table 8-8 results to one year’s worth of new building construction 

in the state to estimate statewide energy-related reduction in carbon emissions from 

adoption of a more energy efficient code. The total reduction in carbon emissions ranges 

widely across building types, and is correlated to the reductions in energy use. The 

adoption of the LEC design as the state’s energy code for commercial buildings decreases 

carbon emissions by 2.1 million metric tons over the 10-year study period for one year’s 

worth of new commercial construction for these building types. Assuming that the 

buildings considered in this study are generally representative of the entire new building 

stock in the state, the results for the LEC design can be extrapolated to estimate total 

statewide reductions in carbon emissions of 3.2 million metric tons over the 10-year 

study period. 

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Florida 

Table 8-9 Statewide Change in Total Carbon Emissions (t) for One Year of 

Construction, 10-Year, Florida – Metric Tons 

Building Subcategory m 2 ft2 Energy Code
 

Type Weighting (1000s) (1000s) LEC
 

APART04 44.9 % 1923 20 704 -351 846
 

APART06 55.1 % 2356 25 359 -463 242
 

HOTEL15 100.0 % 596 6414 -96 506 

HIGHS02 100.0 % 1552 16 705 -362 638 

OFFIC03 37.4 % 676 7277 -153 836 

OFFIC08 40.4 % 729 7848 -131 490 

OFFIC16 22.2 % 401 4318 -76 624 

RETAIL1 100.0 % 2381 25 627 -409 884 

RSTRNT1 100.0 % 136 1460 -53 533 

Total 10 750 115 711 -2 099 598 

Note: Dormitories are excluded because no floor area category is 

reported in the construction data. 

8.2.4 Life-Cycle Costs 

Table 8-10 reports the average change in life-cycle cost over 10 years, per m2 (ft2

), by 

building type. As discussed in Section 5.2, life-cycle costs include construction costs, 

maintenance, repair, and replacement costs, energy costs, and residual values. The 

average change in life-cycle costs per unit of floor area varies significantly across 

building types. 

Table 8-10 Average Per Unit Change in Life-Cycle Costs, 10-Year, Florida 

Building Energy Code 

Type LEC 

$/m2 $/ft2 

APART04 -$2.59 -$0.24 

APART06 -$4.08 -$0.38 

DORMI04 -$19.87 -$1.85 

DORMI06 -$9.00 -$0.84 

HOTEL15 -$0.69 -$0.06 

HIGHS02 -$15.43 -$1.43 

OFFIC03 -$19.75 -$1.83 

OFFIC08 -$22.10 -$2.05 

OFFIC16 -$1.59 -$0.15 

RETAIL1 -$5.18 -$0.48 

RSTRNT1 -$73.78 -$6.85 

Table 8-11 applies the Table 8-10 results to one year’s worth of new building 

construction in the state to estimate statewide change in total life-cycle costs from 

adoption of a more energy-efficient code. Adopting the LEC design decreases total life61
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Florida 

cycle costs by $91.4 million, and reduces costs for all 9 building types. Hotels and 

high-rise office buildings realize the smallest reductions in life-cycle costs. Assuming 

that the buildings considered in this study are generally representative of the entire new 

building stock in the state, the results for the LEC design can be extrapolated to estimate 

an increase in total statewide life-cycle costs of $151.3 million over the 10-year study 

period. 

Table 8-11 Statewide Change in Life-Cycle Costs for One Year of Construction, 

10-Year, Florida 

Building Subcategory m 2 ft2 Energy Code
 

Type Weighting (1000s) (1000s)
 LEC 

APART04 44.9 % 1923 20 704 -$4 984 164 

APART06 55.1 % 2356 25 359 -$9 607 112 

HOTEL15 100.0 % 596 6414 -$409 194 

HIGHS02 100.0 % 1552 16 705 -$23 950 746 

OFFIC04 37.4 % 676 7277 -$13 353 416 

OFFIC08 40.4 % 729 7848 -$16 112 836 

OFFIC16 22.2 % 401 4318 -$638 697 

RETAIL1 100.0 % 2381 25 627 -$12 330 802 

RSTRNT1 100.0 % 136 1460 -$10 005 885 

Total 10 750 115 711 -$91 392 851 

Note: Dormitories are excluded because no floor area category is 

reported in the construction data. 

8.3 State Summary 

Florida has consistently been one of the earliest adopters of the most recent edition of the 

ASHRAE 90.1 Standard as its state energy code for commercial buildings, and is one of 

the largest states in the country. The adoption of the LEC design, which goes beyond 

ASHRAE 90.1-2007, leads to sizeable total energy use, energy cost, and carbon emissions 

reductions while significantly decreasing life-cycle costs. Based on the average annual 

new commercial construction in the state from 2003 to 2007 and a 10-year study period, 

adopting the LEC design as the state’s energy code for commercial buildings would lead 

to energy savings of 3790.5 GWh (12942.3 GBtu), energy cost savings of $333 million, 

and carbon emissions savings of 3.2 million metric tons of carbon emissions, and lifecycle cost savings of $151.3 million for one year’s worth of commercial building 

construction. 

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9 

Maryland 

Maryland 

Maryland is selected for this study for two reasons. First, Maryland represents the Middle 

Atlantic region of the United States. Second, the state is comparable in new construction 

volume to several other states selected for this study, which allows for comparisons 

across states. Maryland is located primarily in Climate Zone 4 with the northwestern 

portion of the state located in Zone 5. Only one city, Baltimore, is simulated for this 

study and is located in Zone 4. As of December 2011, the state had adopted ASHRAE 

90.1-2007 as its state energy code for commercial buildings. 

Table 9-1 provides an overview of Maryland’s simulated energy use keyed to building 

types and energy codes. Average energy use varies across building types. The 8-story 

office building uses the least amount of energy at 80 kWh/m2 to 100 kWh/m2 (25 kBtu/ft2 

to 32 kBtu/ft2) annually. The high school uses the greatest amount of energy at 

192 kWh/m2 to 207 kWh/m2 (61 kBtu/ft2 to 66 kBtu/ft2

) annually. 

Table 9-1 Average Annual Energy Use by Building Type and Energy Code, 

Maryland 

Building 

Type 

Energy Code 

2007 

kWh/m2 kBtu/ft2 

LEC 

kWh/m2 kBtu/ft2 

APART04 

APART06 

151 48 

149 47 

134 43 

131 42 

DORMI04 

DORMI06 

112 35 

164 52 

98 31 

144 46 

HOTEL15 153 48 132 42 

HIGHS02 207 66 192 61 

OFFIC03 

OFFIC08 

OFFIC16 

107 34 

100 32 

148 47 

85 27 

80 25 

124 39 

RETAIL1 114 36 97 31 

RSTRNT1 161 51 117 37 

The detailed analysis for this state reports the changes in energy use, energy costs, 

energy-related carbon emissions, and life-cycle costs from adoption of the LEC design. 

The results are reported in terms of average percentage savings and total savings on a 

statewide basis. There is no within-state variation to consider for this state since only one 

city is simulated for the state (Baltimore). 

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Maryland 

9.1 Percentage Savings 

Changes in percentage terms allow for direct comparisons across building types within a 

state. This section discusses the average percentage changes from investing in a more 

energy efficient design for the state of Maryland. 

Table 9-2 shows the percentage change in energy use, energy costs, energy-related 

carbon emissions, and life-cycle costs for the LEC design relative to ASHRAE 90.1-2007. 

The LEC design realizes changes in energy use ranging from -7.2 % to -27.7 % with an 

average of -15.1 % relative to the ASHRAE 90.1-2007 design. The greatest reduction in 

energy use for the LEC design occurs in restaurants followed by the small and mid-sized 

office buildings. The smallest reductions occur in the high school followed by the 

apartments and dormitories. 

Table 9-2 Average Percentage Change from Adoption of a Newer Code, 10 Year, 

Maryland 

Building LEC 

Type Energy Use Energy Cost Carbon LCC 

APART04 -10.9 -17.1 -16.4 0.2 

APART06 -12.1 -19.9 -19.0 -0.0 

DORMI04 -12.5 -17.8 -17.2 -0.2 

DORMI06 -12.0 -19.7 -18.8 -0.4 

HOTEL15 -13.4 -19.4 -18.7 -0.1 

HIGHS02 -7.2 -16.9 -15.6 -1.7 

OFFIC03 -20.0 -23.4 -23.1 -3.0 

OFFIC08 -19.7 -21.4 -21.2 -2.9 

OFFIC16 -16.0 -20.1 -19.7 -0.3 

RETAIL1 -14.3 -17.3 -17.0 -0.1 

RSTRNT1 -27.7 -33.5 -32.9 -9.0 

Average -15.1 -20.6 -20.0 -1.6 

The LEC design realizes average changes in energy costs from -16.9 % to -33.5 % 

depending on the building type, with an average of -20.6 % overall over 10 years of 

operation. The high school and 4-story apartment building realize the smallest average 

reductions in energy costs while the restaurant realizes the greatest average reductions in 

energy use. The energy costs are reduced by a greater percentage than energy use because 

the energy efficiency measures decrease electricity consumption by a greater percentage 

than natural gas consumption. For 10 of the 11 building types, the energy efficiency 

measures increase natural gas consumption while decreasing electricity consumption. The 

shift is most prevalent for the high school, where the increase in natural gas consumption 

offsets 40.6 % of the reduction in electricity consumption, and results in a percentage 

reduction in energy costs that is over two times greater than the percentage reduction in 

energy use. The LEC design incorporates daylighting and overhangs into the building 

design for cities in Zone 4 and Zone 5, which decreases the building’s internal and 

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Maryland 

external heat gains, respectively. The shift in energy use from electricity to natural gas 

consumption to meet the greater heating loads decreases energy costs because natural gas 

is cheaper on a per unit of energy basis relative to electricity. 

The LEC design leads to average changes in carbon emissions ranging from -15.6 % 

to -32.9 % depending on the building type, with an average of -20.0 % across all building 

types. As would be expected, a more energy efficient building design results in greater 

reductions in carbon emissions. Similar to energy costs, the percentage reduction in 

carbon emissions is greater than the percentage reduction in energy use because the 

energy efficiency measures adopted decrease electricity consumption by a greater 

percentage than natural gas consumption. The greater relative reduction in electricity 

consumption leads to additional emissions reductions because the average emissions 

reduction per unit of energy from natural gas consumption is much lower than the 

average emissions reductions from electricity consumption. 

The average change in life-cycle costs for the LEC design over a 10-year study period 

ranges from -9.0 % to 0.2 %. The 4-story apartment building is the only building type 

that realizes a percentage increase in life-cycle costs. The restaurant, 3-story office 

building, and 8-story office building are the building types that realize the greatest 

reductions in average life-cycle costs. Given that 10 of 11 buildings types realize an 

average percentage decrease in life-cycle costs, the LEC design is cost-effective for the 

state to adopt as its state energy code for commercial buildings. 

9.2 Total Savings 

How much can Maryland save, in terms of energy use, energy costs, and carbon 

emissions, from adopting a more stringent state energy code for commercial buildings? 

What are the life-cycle costs associated with the new energy code adoption? To answer 

these questions, it is first necessary to estimate savings per unit of floor area for each 

building type in the state. 

9.2.1 Energy Use 

Table 9-3 reports the average per unit change in annual energy use by building type for 

the LEC design in the state.21 The reduction per m2 (ft2

) is multiplied by the estimated m2 

(ft2) of new construction of each building type. Table 9-4 reports the estimated average 

annual floor area of new construction and the total annual reduction in energy use for 

each building type. The weightings within a category (e.g. small, medium, and large 

21 A simple average for a state is used because no data for a weighted average is available regarding the 

amount of new construction on a city-by-city basis. 

65
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Maryland 

office buildings) are based on the national average percentage of new building 

construction for the category that is represented by each subcategory.22 

Table 9-3 Average Per Unit Change in Annual Energy Use, Maryland 

Building Energy Code 

Type LEC 

kWh/m2 kBtu/ft2 

APART04 -16.4 -5.2 

APART06 -18.0 -5.7 

DORMI04 -14.0 -4.4 

DORMI06 -19.7 -6.3 

HOTEL15 -20.5 -6.5 

HIGHS02 -21.3 -6.8 

OFFIC03 -14.9 -4.7 

OFFIC08 -19.6 -6.2 

OFFIC16 -23.6 -7.5 

RETAIL1 -16.2 -5.2 

RSTRNT1 -44.6 -14.2 

The annual reduction in energy use ranges widely across building types with reported 

floor area data, but the LEC design decreases overall energy use across the state. The 

adoption of the LEC design as the state’s energy code would save energy for all building 

types and 37.3 GWh (127.5 GBtu) of total energy use annually for one year’s worth of 

new construction for these building types. Assuming that the buildings considered in this 

study, which represent 60.0 % of all new commercial floor space in the state, are 

generally representative of the entire new commercial building stock in the state, the 

results can be extrapolated to estimate the total statewide savings to be 62.2 GWh 

(212.4 GBtu) per year. These savings imply 622.2 GWh (2124.5 GBtu) in energy savings 

over the 10-year study period. 

22 State-level subcategory data are not available. 

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Maryland 

Table 9-4 Statewide Change in Annual Energy Use for One Year of Construction, 

Maryland 

Building Subcategory m 2 ft2 Energy Code 

Type Weighting (1000s) (1000s) LEC 

kWh kBtu 

APART04 44.9 % 300 3233 -4 912 108 -16 772 048
 

APART06 55.1 % 368 3960 -6 629 761 -22 636 856
 

HOTEL15 100.0 % 165 1778 -3 376 646 -11 529 321 

HIGHS02 100.0 % 305 3286 -4 561 245 -15 574 052 

OFFIC03 37.4 % 210 2258 -4 473 057 -15 272 939 

OFFIC08 40.4 % 226 2435 -4 436 129 -15 146 851 

OFFIC16 22.2 % 124 1340 -2 942 128 -10 045 692 

RETAIL1 100.0 % 310 3334 -5 028 330 -17 168 881 

RSTRNT1 100.0 % 22 235 -972 937 -3 322 027 

Total 2031 21 859 -37 332 341 -127 468 665 

Note: Dormitories are excluded because no floor area category is reported in the 

construction data. 

The relative reduction in energy use varies across the 9 building types with reported floor 

area data for the LEC design relative to ASHRAE 90.1-2007. The greatest reductions are 

for 6-story apartment buildings followed by retail stores, 4-story apartment buildings, 

high schools, and 3- and 8-story office buildings. The smallest reductions are for 

restaurants followed by the high-rise buildings. Building types that represent a greater 

amount of new floor area realize the largest changes in energy use. The building types 

that have the greatest percentage reductions in energy use are not always the same 

buildings that lead to the greatest total reductions for the state. The building types that 

lead to the greatest estimated reductions in energy use -- retail stores and 6- and 4-story 

apartment buildings-- only rank 5th, 8th, and 10th in percentage reduction, respectively, 

among the 11 building types, as reported in Table 9-2. 

9.2.2 Energy Costs 

Table 9-5 reports the average per unit change in energy costs by building type. Energy 

costs are calculated using the annual energy use, state average energy cost rates, and 

regional energy price escalation rates as defined in Section 3.2. 

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Maryland 

Table 9-5 Average Per Unit Change in Energy Costs, 10-Year, Maryland
 

Building Energy Code 

Type LEC 

$/m2 $/ft2 

APART04 -$17.00 -$1.58 

APART06 -$19.83 -$1.84 

DORMI04 -$13.62 -$1.27 

DORMI06 -$21.45 -$1.99 

HOTEL15 -$19.85 -$1.84 

HIGHS02 -$20.88 -$1.94 

OFFIC03 -$21.12 -$1.96 

OFFIC08 -$19.05 -$1.77 

OFFIC16 -$23.97 -$2.23 

RETAIL1 -$15.57 -$1.45 

RSTRNT1 -$41.93 -$3.90 

Table 9-6 reports the statewide changes in total energy costs by building type, which 

account for one year’s worth of new construction evaluated over 10 years of building 

operation. All building types realize energy cost savings for the LEC design, with the 

energy cost savings being highly correlated with energy use savings. Overall, total 

reductions in energy costs total $37.4 million for adopting the LEC design relative to 

ASHRAE 90.1-2007. Assuming that the buildings considered in this study, which 

represent 60.0 % of all new commercial floor space in the state, are generally 

representative of the entire new commercial building stock in the state, the results for the 

LEC design can be extrapolated to estimate the total energy cost savings of $62.4 million 

over the 10-year study period. 

Table 9-6 Statewide Change in Energy Costs for One Year of Construction, 

10-Year, Maryland 

Building Subcategory m 2 ft2 Energy Code
 

Type Weighting (1000s) (1000s)
 LEC 

APART04 44.9 % 300 3233 -$5 107 758
 

APART06 55.1 % 368 3960 -$7 296 692
 

HOTEL15 100.0 % 165 1778 -$3 278 577 

HIGHS02 100.0 % 305 3286 -$4 301 405 

OFFIC03 37.4 % 210 2258 -$4 430 681 

OFFIC08 40.4 % 226 2435 -$4 309 892 

OFFIC16 22.2 % 124 1340 -$2 983 322 

RETAIL1 100.0 % 310 3334 -$4 823 614 

RSTRNT1 100.0 % 22 235 -$913 865 

Total 2031 21 859 -$37 445 805 

Note: Dormitories are excluded because no floor area category is 

reported in the construction data. 

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Maryland 

9.2.3 Energy-related Carbon Emissions 

Table 9-7 reports the average reduction in energy-related carbon emissions over 10 years, 

per m 2 (ft2

), by building type. The carbon emissions estimation approach is defined in 

Section 5.3. 

Table 9-7 Average Per Unit Change in Carbon Emissions, 10-Year, Maryland 

Building Energy Code 

Type LEC 

kg/m2 lb/ft2 

APART04 -116.1 -23.8 

APART06 -134.8 -27.6 

DORMI04 -93.5 -19.1 

DORMI06 -145.9 -29.9 

HOTEL15 -136.3 -27.9 

HIGHS02 -139.6 -28.6 

OFFIC03 -144.7 -29.6 

OFFIC08 -130.8 -26.8 

OFFIC16 -163.9 -33.6 

RETAIL1 -107.0 -21.9 

RSTRNT1 -288.6 -59.1 

Table 9-8 applies the Table 9-7 results to one year’s worth of new building construction 

in the state to estimate statewide reduction in carbon emissions from adoption of a more 

energy efficient code. The total reduction in carbon emissions ranges widely across 

building types, and is correlated with each building’s total reductions in energy use. 

However, there is not a perfect correlation because the magnitude of the offsetting natural 

gas increase for 10 of 11 building types varies. The adoption of the LEC design as the 

state’s energy code decreases carbon emissions by 269 357 metric tons over the 10-year 

study period for one year’s worth of new commercial construction for these building 

types. Assuming that the buildings considered in this study are generally representative of 

the entire new commercial building stock in the state, the results for the LEC design can 

be extrapolated to estimate statewide reductions in carbon emissions of 448 928 tons over 

the 10-year study period. 

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Maryland 

Table 9-8 Statewide Change in Total Carbon Emissions for One Year of 

Construction, 10-Year, Maryland – Metric Tons 

Building Subcategory m 2 ft2 Energy Code
 

Type Weighting (1000s) (1000s) LEC
 

APART04 44.9 % 300 3233 -34 859
 

APART06 55.1 % 368 3960 -49 581
 

HOTEL15 100 % 165 1778 -22 508 

HIGHS02 100.0 % 305 3286 -42 619 

OFFIC03 37.4 % 210 2258 -30 361 

OFFIC08 40.4 % 226 2435 -29 581 

OFFIC16 22.2 % 124 1340 -20 407 

RETAIL1 100.0 % 310 3334 -33 138 

RSTRNT1 100.0 % 22 235 -6301 

Total 2031 21 859 -269 357 

Note: Dormitories are excluded because no floor area category is 

reported in the construction data. 

9.2.4 Life-Cycle Costs 

Table 9-9 reports the average change in life-cycle cost over 10 years, per m2 (ft2

), by 

building type. As discussed in Section 5.2, life-cycle costs include construction costs, 

maintenance, repair, and replacement costs, energy costs, and residual values. 

Table 9-9 Average Per Unit Change in Life-Cycle Costs, 10-Year, Maryland 

Building Energy Code 

Type LEC 

$/m2 $/ft2 

APART04 $2.13 $0.20 

APART06 -$0.28 -$0.03 

DORMI04 -$1.52 -$0.14 

DORMI06 -$4.34 -$0.40 

HOTEL15 -$0.64 -$0.06 

HIGHS02 -$14.23 -$1.32 

OFFIC03 -$26.42 -$2.45 

OFFIC08 -$26.11 -$2.43 

OFFIC16 -$2.22 -$0.21 

RETAIL1 -$0.59 -$0.05 

RSTRNT1 -$131.12 -$12.18 

Table 9-10 applies the Table 9-9 results to one year’s worth of new building construction 

in the state to estimate the change in statewide life-cycle costs from adoption of more 

energy-efficient codes. The change in life-cycle costs varies widely across building types, 

with 8 of 9 building types realizing reductions in life-cycle costs. Three-story and 8-story 

office buildings realize total reductions in life-cycle costs of greater than $5.5 million. 

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Maryland 

The LEC design leads to statewide reductions in life-cycle costs of $17.3 million relative 

to ASHRAE 90.1-2007. Assuming that the buildings considered in this study are generally 

representative of the entire new commercial building stock in the state, the results for the 

LEC design can be extrapolated to estimate the total statewide life-cycle cost increases of 

$28.8 million over the 10-year study period. 

Table 9-10 Statewide Change in Life-Cycle Costs for One Year of Construction, 

10-Year, Maryland 

Building Subcategory m 2 ft2 Energy Code
 

Type Weighting (1000s) (1000s) LEC
 

APART04 44.9 % 300 3233 $640 249
 

APART06 55.1 % 368 3960 -$104 036
 

HOTEL15 100.0 % 165 1778 -$106 294 

HIGHS02 67.5 % 305 3286 -$2 931 692 

OFFIC03 37.4 % 210 2258 -$5 541 957 

OFFIC08 40.4 % 226 2435 -$5 907 246 

OFFIC16 22.2 % 124 1340 -$276 765 

RETAIL1 100.0 % 310 3334 -$183 061 

RSTRNT1 100.0 % 22 235 -$2 857 706 

Total 2031 21 859 -$17 268 507 

Note: Dormitories are excluded because no floor area category is 

reported in the construction data. 

9.3 State Summary 

As of December 2011, Maryland had adopted ASHRAE 90.1-2007 as its energy code for 

commercial buildings. The adoption of the LEC design, which goes beyond ASHRAE 

90.1-2007, leads to impressive energy use, energy cost, and energy-related carbon 

emissions reductions in a life-cycle cost-effective manner. Based on the average annual 

new construction in the state from 2003 to 2007 and a 10-year study period, adopting the 

LEC design as the state’s energy code would lead to energy savings of 622.2 GWh 

(2124.5 GBtu), energy cost savings of $62.4 million, and carbon emissions reductions of 

448 928 metric tons while decreasing life-cycle costs by $28.8 million for one year’s 

worth of commercial building construction. 

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Maryland 

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Oregon 

10 Oregon 

Oregon is selected for this study because the state represents the Northwest and the 

associated climate zones (Zone 4C and Zone 5B) in that region of the United States. 

Oregon is one of four states selected for this study that has adopted ASHRAE 90.1-2007 

as its state energy code for commercial buildings, allowing comparisons across states. 

Table 10-1 provides an overview of Oregon’s simulated energy use keyed to building 

types and energy codes. Average energy use varies across building types and building 

designs. The 8-story office building uses the least amount of energy at 72 kWh/m2 to 91 

kWh/m2 (23 kBtu/ft2 to 29 kBtu/ft2

) annually. The high school uses the greatest amount 

of energy at 179 kWh/m2 to 188 kWh/m2 (57 kBtu/ft2 to 60 kBtu/ft2). 

Table 10-1 Average Annual Energy Use by Building Type and Energy Code, 

Oregon 

Building 

Type 

Energy Code 

2007 

kWh/m2 kBtu/ft2 

LEC 

kWh/m2 kBtu/ft2 

APART04 

APART06 

124 39 

125 40 

112 35 

111 35 

DORMI04 

DORMI06 

96 30 

136 43 

84 27 

122 39 

HOTEL15 133 42 115 37 

HIGHS02 188 60 179 57 

OFFIC03 

OFFIC08 

OFFIC16 

96 30 

91 29 

132 42 

76 24 

72 23 

109 34 

RETAIL1 104 33 90 29 

RSTRNT1 142 45 102 32 

The detailed analysis for this state reports the changes in energy use, energy costs, 

energy-related carbon emissions, and life-cycle costs from adoption of a more stringent 

energy code for commercial buildings. The results are reported in terms of average 

percentage savings on a statewide and city-by-city basis and as total savings on a 

statewide basis. 

10.1 Percentage Savings 

Changes in percentage terms allow for direct comparisons across building types and 

locations within a state. This section discusses the average percentage changes from 

investing in a more energy efficient design in the state of Oregon. 

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Oregon 

10.1.1 Statewide Building Comparison 

Table 10-2 shows the percentage change in energy use, energy costs, energy-related 

carbon emissions, and life-cycle costs for the LEC design relative to ASHRAE 90.1-2007. 

There is significant variation in the percentage change in energy use for the LEC design 

relative to ASHRAE 90.1-2007, ranging from -4.9 % to -28.5 % depending on the 

building type with an overall average of -15.0 %. 

Table 10-2 Average Percentage Change in Energy Use from Adoption of a Newer 

Code, 10-Year, Oregon 

LEC Building 

Type Energy Use Energy Cost Carbon LCC 

APART04 -10.0 -15.0 -15.4 1.1 

APART06 -10.9 -17.1 -17.7 1.0 

DORMI04 -12.7 -16.7 -17.0 -1.0 

DORMI06 -10.6 -16.7 -17.1 0.7 

HOTEL15 -13.8 -18.4 -18.8 0.9 

HIGHS02 -4.9 -11.5 -12.1 -0.0 

OFFIC03 -21.2 -23.5 -23.6 -3.5 

OFFIC08 -20.9 -22.0 -22.0 -3.0 

OFFIC16 -17.8 -20.9 -21.1 1.0 

RETAIL1 -13.2 -15.3 -15.4 0.8 

RSTRNT1 -28.5 -33.0 -33.4 -4.5 

Average -15.0 -19.1 -19.4 -0.6 

There is a significant variation in the average percentage change in energy costs for the 

LEC design, ranging from -11.5 % to -33.0 % depending on the building type, with an 

average of -19.1 % for 10 years of building operation. The energy costs are reduced by a 

greater percentage than energy use because the energy efficiency measures decrease 

electricity consumption by a greater percentage than natural gas consumption. In fact, for 

all 11 building types the energy efficiency measures increase natural gas consumption 

while decreasing electricity consumption. The shift is most prevalent for the high school, 

where the increase in natural gas consumption offsets 59.9 % of the reduction in 

electricity consumption, and results in a percentage reduction in energy costs that is over 

two times greater than the percentage reduction in energy use. The LEC design 

incorporates daylighting and overhangs into the building design for cities in Zone 4 and 

Zone 5, which decreases the building’s internal and external heat gains, respectively. The 

shift in energy use from electricity to natural gas consumption to meet the greater heating 

loads decreases energy costs because natural gas is cheaper on a per unit of energy basis 

relative to electricity. 

There is significant variation in the average percentage change in energy-related carbon 

emissions for the LEC design across building types, ranging from -12.1 % to -33.4 % 

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Oregon 

with an average of -19.4 %. As would be expected, a more energy efficient building 

design results in greater reductions in carbon emissions. Similar to energy costs, the 

percentage reduction in carbon emissions is greater than the percentage reduction in 

energy use because the energy efficiency measures adopted decrease electricity 

consumption by a greater percentage than natural gas consumption. The greater relative 

reduction in electricity consumption leads to additional emissions reductions because the 

average emissions reduction per unit of energy from natural gas consumption is much 

lower than the average emissions reductions from electricity consumption. 

The LEC design results in significant variations in life-cycle costs across building types. 

Of the 11 building types, 5 realize a reduction in life-cycle costs for a 10-year study 

period. The percentage change in life-cycle costs for the LEC design ranges from -4.5 % 

to 1.1 %. Based on the overall average change of -0.6 % in life-cycle costs, the LEC 

design may be cost-effective for the state to adopt as its state energy code. 

10.1.2 City Comparisons 

Simulations are run for 9 cities located in Oregon: Astoria, Eugene, Medford, North 

Bend, Portland, and Salem in Climate Zone 4C and Burns, Pendleton, and Redmond in 

Climate Zone 5B. The results vary across cities within the state for several reasons. First, 

the state is covered by two climate zones. The LEC design requirements vary across 

climate zones and will impact the relative energy efficiency of the building. Second, 

cities within the same climate zone still have some variation in the local climate, which 

can lead to variation in energy consumption. Third, construction material and labor costs 

vary by locality. 

Table 10-3 shows the percentage change in energy use, energy costs, energy-related 

carbon emissions, and life-cycle costs for the LEC design relative to ASHRAE 90.1-2007 

for each city in the state. 

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Oregon 

Table 10-3 Average Percentage Change in Energy Use from Adoption of Newer 

Codes by City, 10-Year, Oregon 

Cities Zone LEC 

Energy Use Energy Cost Carbon LCC 

Astoria 4C -14.2 -18.5 -18.8 -0.5 

Eugene 4C -15.6 -19.6 -20.0 -0.7 

Medford 4C -15.6 -19.6 -20.0 -0.9 

North Bend 4C -16.2 -20.6 -20.8 -0.3 

Portland 4C -16.0 -19.7 -20.0 -0.2 

Salem 4C -15.3 -19.3 -19.7 -0.7 

Burns 5B -12.9 -17.4 -17.8 -0.8 

Pendleton 5B -15.1 -19.0 -19.5 -0.9 

Redmond 5B -13.7 -18.2 -18.7 -0.6 

Average -15.0 -19.1 -19.5 -0.6 

The average percentage change in energy use for all building types from adopting the 

LEC design varies across cities from -12.9 % to -16.2 %. Cities in Zone 4C realize 

slightly greater reductions in energy use relative to Zone 5B. The average change in 

energy costs for all building types varies across cities, from -17.4 % to -20.6 %, with 

Zone 4C realizing a slightly larger change than Zone 5B for 10 years of building 

operation. For all cities, the LEC design results in percentage changes in carbon 

emissions ranging from -17.8 % to -20.8 % with an overall average of -19.5 %. 

Reductions in energy costs and carbon emissions are larger than the reductions in energy 

use because electricity consumption decreases while natural gas consumption increases. 

Adoption of the LEC design results in average percentage reductions in life-cycle costs 

for all cities for a 10-year study period, ranging from -0.2 % to -0.9 %. 

10.2 Total Savings 

How much can Oregon save, in terms of energy use, energy costs, and carbon emissions, 

from adopting a more stringent state energy code for commercial buildings? What are the 

life-cycle costs associated with the new energy code adoption? To answer these 

questions, it is first necessary to estimate savings per unit of floor area for each building 

type in the state. 

10.2.1 Energy Use 

Table 10-4 reports the average per unit change in annual energy use by building type in 

the state.23 The reduction per m2 (ft2

) is multiplied by the estimated m2 (ft2) of new 

23 A simple average for a state is used because no data for a weighted average is available regarding the 

amount of new construction on a city-by-city basis. 

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Oregon 

construction of each building type. Table 10-5 reports the estimated average annual floor 

area of new construction and the total annual reduction in energy use for each building 

type. The weightings within a category (e.g. small, medium, and large office buildings) 

are based on the national average percentage of new building construction for the 

category that is represented by each subcategory.24 

Table 10-4 Average Per Unit Change in Annual Energy Use, Oregon 

Building Energy Code 

Type LEC 

kWh/m2 kBtu/ft2 

APART04 -12.4 -3.9 

APART06 -13.6 -4.3 

DORMI04 -12.0 -3.8 

DORMI06 -14.4 -4.6 

HOTEL15 -18.2 -5.8 

HIGHS02 -20.2 -6.4 

OFFIC03 -9.3 -2.9 

OFFIC08 -19.1 -6.0 

OFFIC16 -23.4 -7.4 

RETAIL1 -13.6 -4.3 

RSTRNT1 -40.3 -12.8 

The LEC design decreases overall energy use across the state. The adoption of the LEC 

design as the state’s energy code saves energy for all building types and 13.9 GWh (47.4 

GBtu) of total energy use annually for one year’s worth of new construction for these 

building types. Assuming that the buildings considered in this study, which represent 

53.1 % of all new commercial floor space in the state, are generally representative of the 

entire new commercial building stock in the state, the results can be extrapolated to 

estimate the total statewide savings to be 26.1 GWh (89.2 GBtu) in energy savings per 

year. These savings imply 261.4 GWh (892.4 GBtu) in energy savings over the 10-year 

study period. 

24 State-level subcategory data are not available. 

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Oregon 

Table 10-5 Statewide Change in Annual Energy Use for One Year of Construction, 

Oregon 

Building Subcategory m 2 ft2 Energy Code 

Type Weighting (1000s) (1000s) LEC 

kWh kBtu 

APART04 44.9 % 113 1213 -1 394 046 -4 759 872
 

APART06 55.1 % 138 1486 -1 871 932 -6 391 581
 

HOTEL15 100.0 % 72 776 -1 314 161 -4 487 110 

HIGHS02 100.0 % 130 1401 -1 208 058 -4 124 830 

OFFIC03 37.4 % 69 743 -1 397 542 -4 771 808 

OFFIC08 40.4 % 74 801 -1 418 430 -4 843 130 

OFFIC16 22.2 % 41 441 -957 706 -3 270 019 

RETAIL1 100.0 % 276 2976 -3 771 343 -12 876 986 

RSTRNT1 100.0 % 14 146 -544 826 -1 860 269 

Total 927 9982 -13 878 043 -47 385 606 

Note: Dormitories are excluded because no floor area category is reported in the 

construction data. 

The statewide change in total energy use varies across building types. Building types that 

represent a greater amount of new floor area realize the largest changes in energy use. 

The building types that have the greatest percentage reduction in energy use are not 

always the same buildings that lead to the greatest total reductions for the state. For 

example, the building types that lead to the greatest estimated reductions in energy use 

for the LEC design -- retail stores and 6-story apartment buildings -- only rank 6th and 8th 

in percentage reduction, respectively, among the 11 building types, as reported in Table 

10-2. 

10.2.2 Energy Costs 

Table 10-6 reports the average per unit change in energy costs by building type. Energy 

costs are calculated using the annual energy use, state average energy cost rates, and 

regional energy price escalation rates as defined in Section 3.2. 

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Oregon 

Table 10-6 Average Per Unit Change in Energy Costs, 10-Year, Oregon
 

Building Energy Code 

Type LEC 

$/m2 $/ft2 

APART03 -$8.38 -$0.78 

APART06 -$9.70 -$0.90 

DORMI03 -$7.51 -$0.70 

DORMI06 -$10.26 -$0.95 

HOTEL15 -$11.33 -$1.05 

HIGHS02 -$9.48 -$0.88 

OFFIC03 -$12.39 -$1.15 

OFFIC08 -$11.44 -$1.06 

OFFIC16 -$14.61 -$1.36 

RETAIL1 -$8.25 -$0.77 

RSTRNT1 -$24.09 -$2.24 

Table 10-7 reports the statewide changes in total energy costs by building type and 

building design, which account for one year’s worth of new construction evaluated over 

10 years of building operation. The LEC design leads to statewide reductions in energy 

costs of $9.2 million. All building types realize energy cost savings, ranging from 

$325 917 to $2.3 million. The total reductions in energy costs are correlated with total 

reductions in energy use, but there is some variation due to the variation in the energy 

source of the reductions. 

Assuming that the buildings considered in this study, which represent 53.1 % of all new 

commercial floor space in the state, are generally representative of the entire new 

commercial building stock in the state, the results for the LEC design can be extrapolated 

to estimate the total statewide energy cost savings of $17.4 million over the 10-year study 

period. 

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Oregon 

Table 10-7 Statewide Change in Energy Costs for One Year of Construction, 

10-Year, Oregon 

Building Subcategory m 2 ft2 Energy Code
 

Type Weighting (1000s) (1000s) LEC
 

APART04 44.9 % 113 1213 -$944 794 

APART06 55.1 % 138 1486 -$1 338 087 

HOTEL15 100.0 % 72 776 -$816 090 

HIGHS02 67.5 % 130 1401 -$1 233 331 

OFFIC03 37.4 % 69 743 -$855 651 

OFFIC08 40.4 % 74 801 -$851 595 

OFFIC16 22.2 % 41 441 -$598 644 

RETAIL1 100.0 % 276 2976 -$2 281 802 

RSTRNT1 100.0 % 14 146 -$325 917 

Total 927 9982 -$9 245 909 

Note: Dormitories are excluded because no floor area category is 

reported in the construction data. 

10.2.3 Energy-related Carbon Emissions 

Table 10-8 reports the average reduction in energy-related carbon emissions over 10 

years, per m 

2 (ft2

), by building type and building design. The carbon emissions estimation 

approach is defined in Section 5.3. 

Table 10-8 Average Per Unit Change in Carbon Emissions, 10-Year, Oregon 

Building Energy Code 

Type LEC 

kg/m2 lb/ft2 

APART04 -70.4 -14.4 

APART06 -81.7 -16.7 

DORMI04 -62.8 -12.9 

DORMI06 -86.4 -17.7 

HOTEL15 -94.7 -19.4 

HIGHS02 -81.0 -16.6 

OFFIC03 -103.5 -21.2 

OFFIC08 -95.4 -19.5 

OFFIC16 -122.2 -25.0 

RETAIL1 -68.9 -14.1 

RSTRNT1 -201.0 -41.2 

Table 10-9 applies the Table 10-8 results to one year’s worth of new building 

construction in the state to estimate statewide total reduction in carbon emissions from 

adoption of a more energy efficient code. Adoption of the LEC design as the state’s 

energy code decreases carbon emissions by 77 601 metric tons over the 10-year study 

period for one year’s worth of new commercial construction for these building types. 

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Oregon 

Assuming that the buildings considered in this study are generally representative of the 

entire new commercial building stock in the state, the results for the LEC design can be 

extrapolated to estimate the total statewide reduction in carbon emissions of 146 141 

metric tons over the 10-year study period. The total reduction in carbon emissions for 

each building type is correlated with its total reduction in energy use. 

Table 10-9 Statewide Change in Total Carbon Emissions for One Year of 

Construction, 10-Year, Oregon – Metric Tons 

Building Subcategory m 2 ft2 Energy Code
 

Type Weighting (1000s) (1000s) LEC
 

APART04 44.9 % 113 1213 -7 937
 

APART06 55.1 % 138 1486 -11 272
 

HOTEL15 100.0 % 72 776 -6823 

HIGHS02 67.5 % 130 1401 -10 544 

OFFIC03 37.4 % 69 743 -7148 

OFFIC08 40.4 % 74 801 -7105 

OFFIC16 22.2 % 41 441 -5007 

RETAIL1 100.0 % 276 2976 -19 047 

RSTRNT1 100.0 % 14 146 -2719 

Total 927 9982 -77 601 

Note: Dormitories are excluded because no floor area category is 

reported in the construction data. 

10.2.4 Life-Cycle Costs 

Table 10-10 reports the average change in life-cycle cost over 10 years, per m2 (ft2), by 

building type. As discussed in Section 5.2, life-cycle costs include construction costs, 

maintenance, repair, and replacement costs, energy costs, and residual values. 

Table 10-10 Average Per Unit Change in Life-Cycle Costs, 10-Year, Oregon 

Building Energy Code 

Type LEC 

$/m2 $/ft2 

APART04 $10.86 $1.01 

APART06 $9.96 $0.93 

DORMI04 -$9.75 -$0.91 

DORMI06 $7.11 $0.66 

HOTEL15 $8.64 $0.80 

HIGHS02 -$0.13 -$0.01 

OFFIC03 -$28.91 -$2.69 

OFFIC08 -$26.16 -$2.43 

OFFIC16 $8.19 $0.76 

RETAIL1 $5.27 $0.49 

RSTRNT1 -$62.04 -$5.76 

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reported in the construction data.

Oregon 

Table 10-11 applies the Table 10-10 results to one year’s worth of new building 

construction in the state to estimate the change in statewide life-cycle costs from adoption 

of a more energy-efficient code. The LEC design leads to an increase in statewide lifecycle costs of $213 782 and increases life-cycle costs for 5 of 9 building types. Retail 

stores and hotels account for a $2.1 million ($1.5 million and $622 209, respectively) 

increase in life-cycle costs. 

Assuming that the buildings considered in this study are generally representative of the 

entire new building stock in the state, the results for the LEC design can be extrapolated 

to estimate the increase in total statewide life-cycle costs of $402 602 over the 10-year 

study period. 

Table 10-11 Statewide Change in Life-Cycle Costs for One Year of Construction, 

10-Year, Oregon 

Building Subcategory m 2 ft2 Energy Code
 

Type Weighting (1000s) (1000s) LEC
 

APART04 44.9 % 113 1213 $1 223 170 

APART06 55.1 % 138 1486 $1 374 597 

HOTEL15 100.0 % 72 776 $622 209 

HIGHS02 100.0 % 130 1401 -$17 512 

OFFIC03 37.4 % 69 743 -$1 995 630 

OFFIC08 40.4 % 74 801 -$1 947 568 

OFFIC16 22.2 % 41 441 $335 656 

RETAIL1 100.0 % 276 2976 $1 458 084 

RSTRNT1 100.0 % 14 146 -$839 223 

Total 927 9982 $213 782 

Note: Dormitories are excluded because no floor area category is 

10.3 State Summary 

Oregon has adopted ASHRAE 90.1-2007 as its state commercial building energy code. On 

average, adopting the LEC design reduces energy use, energy costs, and energy-related 

carbon emissions, but does not do so in a cost-effective manner. Based on the average 

annual new commercial construction in the state from 2003 to 2007 and a 10-year study 

period, adopting the LEC design as the state’s energy code would lead to statewide 

energy savings of 261.4 GWh (892.4 GBtu), energy cost savings of $17.4 million, and 

carbon emissions reductions of 146 141 metric tons at a life-cycle cost of $402 602 for 

one year’s worth of commercial building construction. Oregon is one of two states in this 

report that realize an increase in life-cycle costs from adopting the LEC design. 

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Tennessee 

11 Tennessee 

Tennessee was selected for this study for two reasons. First, Tennessee is one of the four 

states in the country that have adopted ASHRAE 90.1-2004 as its state energy code for 

commercial buildings. Second, the state is comparable in new construction volume to 

several other states selected for this study, which allows for comparisons across states. 

Third, the state represents the Appalachian Mountain region of the U.S. and two climate 

zones. 

Table 11-1 provides an overview of Tennessee’s simulated energy use keyed to building 

types and energy standard edition. Average energy use varies across building types and 

building designs. The 8-story office building uses the least amount of energy at 

80 kWh/m2 to 104 kWh/m2 (25 kBtu/ft2 to 33 kBtu/ft2

) annually. The high school uses 

the greatest amount of energy at 157 kWh/m2 to 180 kWh/m2 (50 kBtu/ft2 to 57 kBtu/ft2

) 

annually. 

Table 11-1 Average Annual Energy Use by Building Type and Energy Code, 

Tennessee 

Building 

Type 

Energy Code 

2004 2007 LEC 

kWh/m2 kBtu/ft2 kWh/m2 kBtu/ft2 kWh/m2 kBtu/ft2 

APART04 141 45 136 43 118 37 

APART06 139 44 135 43 115 37 

DORMI04 104 33 100 32 86 27 

DORMI06 152 48 148 47 127 40 

HOTEL15 127 40 135 43 115 37 

HIGHS02 180 57 175 55 157 50 

OFFIC03 109 35 104 33 81 26 

OFFIC08 104 33 100 32 80 25 

OFFIC16 131 42 139 44 115 36 

RETAIL1 118 37 108 34 90 29 

RSTRNT1 161 51 154 49 108 34 

The detailed analysis for this state reports the changes in energy use, energy costs, 

energy-related carbon emissions, and life-cycle costs from adoption of increasingly 

stringent energy codes. The results are reported in terms of average percentage savings on 

a statewide and city-by-city basis, and as total savings on a statewide basis. 

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Tennessee 

11.1 Percentage Savings 

Changes in percentage terms allow for direct comparisons across building type and
 

location within a state. This section discusses the average percentage changes from
 

investing in more energy efficient designs in the state of Tennessee.
 

11.1.1 Energy Use 

Table 11-2 shows a large variation in percentage changes in energy use for ASHRAE 

90.1-2007 relative to ASHRAE 90.1-2004, ranging from 6.4 % to -8.4 % with an average 

of -2.3 %. For the high-rise, 100 % glazed buildings (16-story office building and 

15-story hotel), ASHRAE 90.1-2007 is actually less energy efficient than ASHRAE 

90.1-2004 because the maximum window U-factor in Zone 3 for buildings with 

fenestration accounting for greater than 40 % of wall surface area is less stringent for 

ASHRAE 90.1-2007 relative to ASHRAE 90.1-2004. The 100 % glazing amplifies the 

energy loss enough to overwhelm the energy efficiency gains obtained from other 

measures, such increased insulation R-values. 

Table 11-2 Average Percentage Change in Energy Use from Adoption of Newer
 

Codes, Tennessee
 

Building Energy Code
 

Type
 2007 LEC 

APART04 -3.7 -16.1
 

APART06 -3.1 -17.3
 

DORMI04 -3.6 -17.3
 

DORMI06 -2.1 -16.1
 

HOTEL15 5.8 -9.6
 

HIGHS02 -3.1 -12.9
 

OFFIC03 -4.6 -25.3
 

OFFIC08 -4.0 -23.4
 

OFFIC16 6.4 -12.3
 

RETAIL1 -8.4 -23.1
 

RSTRNT1 -4.4 -32.9
 

Average -2.3 -18.8 

The LEC design realizes greater percentage changes in energy use relative to ASHRAE 

90.1-2004, ranging from -9.6 % to -32.9 % with an average of -18.8 %. Similar to the 

ASHRAE 90.1-2007 design, the smallest reductions in energy use for the LEC design 

occur in the 16-story office building and hotel. The high school also realizes smaller 

reductions in energy use, which is driven by the assumed building occupancy. Some of 

the additional energy efficiency measures adopted by the LEC design, particularly 

daylighting and overhangs, decrease electricity use while increasing natural gas use. 

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Tennessee 

11.1.2 Energy Costs 

Table 11-3 shows significant variation in the percentage changes in average energy costs 

for ASHRAE 90.1-2007 relative to ASHRAE 90.1-2004, ranging from 6.8 % to -5.3 % 

depending on the building type, with an average of -1.2 %. As with energy use savings, 

adopting ASHRAE 90.1-2007 results in an increase in energy costs relative to ASHRAE 

90.1-2004 for the two high-rise buildings. For these two building types, the percentage 

increase in energy costs is larger than the increase in energy use because electricity 

consumption increases while decreasing natural gas consumption. The offset of natural 

gas with electricity increases energy costs because electricity is more expensive per unit 

of energy. Eight of the remaining nine building types realize smaller percentage 

reductions in energy costs than the reductions in energy use because adopting the 

ASHRAE 90.1-2007 design decreases natural gas consumption by a greater percentage 

than electricity consumption. Only the 6-story dormitory realizes a slightly greater 

reduction in energy costs than its reduction in energy use because electricity consumption 

decreases by a greater percentage than natural gas consumption. 

Table 11-3 Average Percentage Change in Energy Costs, 10-Year, Tennessee 

Building Energy Code 

Type 2007 LEC 

APART04 -3.4 -20.5 

APART06 -2.9 -22.9 

DORMI04 -2.8 -20.4 

DORMI06 -2.3 -21.9 

HOTEL15 6.7 -13.6 

HIGHS02 -2.5 -19.9 

OFFIC03 -2.6 -25.8 

OFFIC08 -1.8 -22.7 

OFFIC16 6.8 -15.0 

RETAIL1 -5.3 -22.6 

RSTRNT1 -2.9 -35.6 

Average -1.2 -21.9 

The LEC design realizes greater reductions in energy costs than the ASHRAE 90.1-2007 

design, with the average percentage change by building type ranging from -13.6 % 

to -35.6 % with an overall average of -21.9 % for 10 years of building operation. The 

reductions in energy costs are greater than the reductions in energy use for 9 of 11 

building types. For these building types, electricity consumption is decreased by a greater 

percentage than natural gas consumption, which leads to additional reductions in energy 

costs. The remaining two building types see percentage reductions in energy costs that 

are marginally smaller than the reductions in energy use because adoption of the LEC 

design decreases natural gas consumption by a greater percentage than electricity 

consumption. 

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11.1.3 Energy-related Carbon Emissions Reduction 

Table 11-4 shows significant variation in the average percentage change in energy-related 

carbon emissions for the ASHRAE 90.1-2007 design across building types, ranging from 

6.9 % to -4.9 % with an average of -1.0 %. The LEC design leads to significant changes 

in average carbon emissions, ranging from -14.3 % to -36.1 % depending on the building 

type with an average of -22.5 % across all building types. As would be expected, a more 

energy efficient building design results in greater reductions in carbon emissions. 

However, the carbon emissions reductions (increases) are smaller (larger) than the energy 

use reductions (increases) for 10 of the 11 building types for the ASHRAE 90.1-2007 

design. Similar to the reductions in energy costs, this result is due to the fuel source of the 

reductions in energy use. For the eight building types that realize smaller reductions in 

carbon emissions than energy use, the percentage reduction in natural gas consumption is 

greater than the reduction in electricity. For the two building types that realize a greater 

percentage increase in carbon emissions than energy use, natural gas consumption is 

decreased while electricity consumption is increased. Similarly, the LEC design realizes a 

greater percentage reduction in natural gas consumption than electricity consumption for 

2 of 11 building types. The remaining building type for the ASHRAE 90.1-2007 design 

and 9 building types for the LEC design realize greater percentage reductions in 

electricity consumption than natural gas consumption. 

Table 11-4 Average Percentage Change in Energy-related Carbon Emissions, 10­

Year, Tennessee 

Building Energy Code 

Type 2007 LEC 

APART04 -3.3 -21.3 

APART06 -2.8 -23.9 

DORMI04 -2.7 -20.9 

DORMI06 -2.3 -22.9 

HOTEL15 6.9 -14.3 

HIGHS02 -2.3 -21.3 

OFFIC03 -2.3 -25.9 

OFFIC08 -1.5 -22.6 

OFFIC16 6.8 -15.4 

RETAIL1 -4.9 -22.5 

RSTRNT1 -2.6 -36.1 

Average -1.0 -22.5 

11.1.4 Life-Cycle Costs 

The most cost-effective building design for each building type is bolded in Table 11-5. 

Based on the life-cycle costs over a 10-year study period, the ASHRAE 90.1-2007 design 

realizes the lowest life-cycle costs for 3 building types while the LEC design has the 

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Tennessee 

lowest life-cycle costs for 6 building types. The current state energy code, ASHRAE 

90.1-2004, results in lower life-cycle costs for the hotel and 16-story office building. 

For 9 building types, ASHRAE 90.1-2007 leads to small percentage reductions in lifecycle costs (-0.9 % or less). The high-rise buildings are the only buildings that realize 

increases in life-cycle costs. Given that 9 building types realize a percentage decrease in 

life-cycle costs, it is likely that ASHRAE 90.1-2007 will decrease total life-cycle costs. 

The LEC design results in reductions in life-cycle costs for 9 building types for a 10-year 

study period. The percentage change in life-cycle costs ranges from -7.7 % to 0.8 %. 

Based on the overall average percentage change of -1.4 % in life-cycle costs, the LEC 

design is likely to be cost-effective for the state to adopt as its state energy code for 

commercial buildings. 

Table 11-5 Average Percentage Change in Life-Cycle Costs, 10-Year, Tennessee 

Building Energy Code 

Type 2007 LEC 

APART04 -0.4 -0.1 

APART06 -0.3 -0.3 

DORMI04 -0.7 -1.1 

DORMI06 -0.2 -0.5 

HOTEL15 0.6 0.8 

HIGHS02 -0.4 -1.7 

OFFIC03 -0.4 -2.6 

OFFIC08 -0.8 -3.0 

OFFIC16 0.8 0.8 

RETAIL1 -0.4 -0.4 

RSTRNT1 -0.9 -7.7 

Average -0.3 -1.4 

11.1.5 City Comparisons 

Simulations are run for 5 cities located in Tennessee: Memphis in Zone 3A and Bristol, 

Chattanooga, Knoxville, and Nashville in Zone 4A. The results vary across cities within 

the state for several reasons. First, the state is covered by two climate zones. The 

ASHRAE 90.1 building design requirements vary across climate zone, and will impact the 

relative energy efficiency of the building. Second, cities within the same climate zone 

still have some variation in the local climate, which can lead to variation in energy 

consumption. Third, construction material and labor costs vary by locality. 

As can be seen in Table 11-6, the average reduction in energy use for all building types 

from adopting newer energy standard editions varies little both across and within climate 

zones. For the ASHRAE 90.1-2007 design, the percentage change in average energy use 

ranges from -1.4 % to -2.8 % with an average of -2.3 %. For the LEC design, the 

percentage change in average energy use ranges from -17.8 % to -19.4 % with an average 

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of -18.8 %. Across both building design alternatives, Zone 3A realizes slightly lower 

reductions in energy use than Zone 4A. 

Table 11-6 Average Percentage Change in Energy Use from Adoption of Newer 

Codes by City, Tennessee 

Cities Zone Energy Code 

2007 LEC 

Memphis 3A -1.4 -17.8 

Bristol 4A -2.8 -18.8 

Chattanooga 4A -2.3 -19.4 

Knoxville 4A -2.2 -19.3 

Nashville 4A -2.5 -18.5 

Average -2.3 -18.8 

The variations in energy costs across cities are a result of two factors, the reductions in 

energy use and the fuel source of the reduction. Table 11-7 shows that the average 

reduction in energy costs for all building types varies minimally across and within 

climate zones. For the ASHRAE 90.1-2007 design, the percentage change in average 

energy costs ranges from -0.7 % to -2.6 % with an average of -1.2 %. The average 

percentage change in energy costs is greater in Zone 3A (-2.6 %) than Zone 4A (-0.8 %). 

For the LEC design, the percentage change in average energy costs ranges from -21.3 % 

to -22.1 % with an average of -21.9 %. Zone 3A realizes slightly greater changes in 

energy use (-22.1 %) than Zone 4A (-21.9 %). 

Table 11-7 Average Percentage Change in Energy Costs by City, 10-Year, 

Tennessee 

Cities Zone Energy Code 

2007 LEC 

Memphis 3A -2.6 -22.1 

Bristol 4A -0.9 -22.0 

Chattanooga 4A -0.8 -22.1 

Knoxville 4A -0.7 -22.1 

Nashville 4A -0.9 -21.3 

Average -1.2 -21.9 

Table 11-8 reports energy-related carbon emissions by city for the state. For all cities, the 

more energy efficient designs result in greater reduction in carbon emissions. The city in 

Zone 3A realizes a slightly greater average percentage change in carbon emissions than 

the cities in Zone 4A for ASHRAE 90.1-2007, -2.9 % versus -1.0 %. The average 

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Tennessee 

emissions reduction does not significantly vary across cities for the LEC design, ranging 

from 22.4 % to 23.3 %. 

Table 11-8 Average Percentage Change in Carbon Emissions by City, Tennessee 

Cities Zone Energy Code 

2007 LEC 

Memphis 3A -2.9 -23.3 

Bristol 4A -1.0 -23.1 

Chattanooga 4A -1.0 -23.1 

Knoxville 4A -0.9 -23.2 

Nashville 4A -1.1 -22.4 

Average -1.0 -23.0 

The data reported in Table 11-9 show that the ASHRAE 90.1-2007 design decreases lifecycle costs across all cities, with changes in life-cycle cost ranging minimally 

from -0.2 % to -0.4 %. The LEC design realizes the greatest reduction in life-cycle costs 

across all cities in the state. There is no significant difference between the average 

percentage changes in life-cycle costs across climate zones. 

Table 11-9 Average Percentage Change in Life-Cycle Costs by City, 10-Year, 

Tennessee 

Cities Zone Energy Code 

2007 LEC 

Memphis 3A -0.4 -1.3 

Bristol 4A -0.3 -1.6 

Chattanooga 4A -0.2 -1.2 

Knoxville 4A -0.2 -1.5 

Nashville 4A -0.3 -1.5 

Average -0.3 -1.4 

11.2 Total Savings 

How much can Tennessee save, in terms of energy use, energy costs, and carbon 

emissions, from adopting a more stringent state energy code for commercial buildings? 

What are the life-cycle costs associated with the new energy code adoption? To answer 

these questions, it is first necessary to estimate savings per unit of floor area for each 

building type in the state. 

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Tennessee 

11.2.1 Energy Use 

Table 11-10 reports the average per unit change in annual energy use by building type 

and building design in the state.25 The reduction per m2 (ft2

) is multiplied by the 

estimated m2 (ft2

) of new construction of each building type. Table 11-11 reports the 

estimated average annual floor area of new construction and the total annual reduction in 

energy use for each building type. The weightings within a category (e.g. small, medium, 

and large office buildings) are based on the national average percentage of new building 

construction for the category that is represented by each subcategory.26 

Table 11-10 Average Per Unit Change in Annual Energy Use, Tennessee 

Building Energy Code 

Type 2007 

kWh/m2 kBtu/ft2 

LEC 

kWh/m2 kBtu/ft2 

APART04 

APART06 

-5.2 -1.6 

-4.3 -1.4 

-22.7 -7.2 

-24.1 -7.6 

DORMI04 

DORMI06 

-3.8 -1.2 

-3.2 -1.0 

-18.1 -5.7 

-24.5 -7.8 

HOTEL15 7.4 2.3 -12.2 -3.9 

HIGHS02 -5.0 -1.6 -27.6 -8.8 

OFFIC03 

OFFIC08 

OFFIC16 

-5.6 -1.8 

-4.2 -1.3 

8.3 2.6 

-23.1 -7.3 

-24.4 -7.8 

-16.1 -5.1 

RETAIL1 -9.8 -3.1 -27.2 -8.6 

RSTRNT1 -7.2 -2.3 -53.1 -16.8 

The annual reduction in energy use ranges widely across building designs, but the 

ASHRAE 90.1-2007 and LEC designs both decrease total statewide energy use across the 

state. The adoption of the ASHRAE 90.1-2007 design results in reductions of 10.1 GWh 

(34.4 GBtu) annually. ASHRAE 90.1-2007 increases total energy use for the two high-rise 

buildings and decreases total energy use for the other 7 building types. 

25 A simple average for a state is used because no data for a weighted average is available regarding the
 

amount of new construction on a city-by-city basis.
 

26 State-level subcategory data are not available.
 

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Tennessee 

Table 11-11 Statewide Change in Annual Energy Use for One Year of Construction, 

Tennessee 

Building Subcategory m 2 ft2 Energy Code 

Type Weighting (1000s) (1000s) 2007 LEC 

kWh kBtu kWh kBtu 

APART04 44.9 % 89 955 -458 546 -1 565 674 -2 010 540 -6 864 847
 

APART06 55.1 % 109 1169 -463 283 -1 581 847 -2 615 546 -8 930 598
 

HOTEL15 100.0 % 136 1469 1 004 599 3 430 133 -1 669 894 -5 701 738 

HIGHS02 100.0 % 362 3895 -2 026 243 -6 918 463 -8 372 078 -28 585 875 

OFFIC03 37.4 % 172 1850 -865 790 -2 956 178 -4 739 500 -16 182 692 

OFFIC08 40.4 % 185 1995 -769 189 -2 626 341 -4 526 951 -15 456 957 

OFFIC16 22.2 % 102 1098 850 344 2 903 441 -1 645 100 -5 617 078 

RETAIL1 100.0 % 716 7710 -7 068 817 -24 135 982 -19 482 585 -66 521 922 

RSTRNT1 100.0 % 40 429 -285 475 -974 734 -2 115 887 -7 224 547 

Total 1911 20 571 -10 082 399 -34 425 646 -47 178 081 -161 086 253 

Note: Dormitories are excluded because no floor area category is reported in the construction data. 

The adoption of the LEC design as the state’s energy code for commercial buildings 

would save 47.2 GWh (161.1 GBtu) of total statewide energy use annually for one year’s 

worth of new construction for these building types. Assuming that the buildings 

considered in this study, which represent 58.4 % of all new commercial floor space in the 

state, are generally representative of the entire new commercial building stock in the 

state, the results can be extrapolated to estimate the statewide savings to be 80.8 GWh 

(275.8 GBtu) per year. These savings imply over 807.8 GWh (2758.3 GBtu) in energy 

savings over the 10-year study period. 

The relative reduction in energy use across building types is consistent across building 

designs. The greatest total reductions are realized by retail stores and high schools 

because they represent 37.5 % and 18.9 %, respectively, of the new construction in the 

state while all other building types represent less than 10 %. The amount of new 

construction overwhelms the relative percentage changes in energy use. For example, the 

building types that lead to the greatest estimated reductions in energy use for the LEC 

design -- retail stores and high schools -- only rank 4th and 9th in percentage reduction, 

respectively, among the 11 building types, as reported in Table 11-2. 

11.2.2 Energy Costs 

Table 11-12 reports the average per unit change in energy costs by building type and 

building design. Energy costs are calculated using the annual energy use, state average 

energy cost rates, and regional energy price escalation rates as defined in Section 3.2. 

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Tennessee 

Table 11-12 Average Per Unit Change in Energy Costs, 10-Year, Tennessee
 

Building Energy Code 

Type 2007 

$/m2 $/ft2 

LEC 

$/m2 $/ft2 

APART04 

APART06 

-$2.88 -$0.27 

-$2.47 -$0.23 

-$17.37 -$1.61 

-$19.35 -$1.80 

DORMI04 

DORMI06 

-$1.83 -$0.17 

-$2.17 -$0.20 

-$13.12 -$1.22 

-$20.21 -$1.88 

HOTEL15 $5.11 $0.47 -$10.34 -$0.96 

HIGHS02 -$2.46 -$0.23 -$19.86 -$1.84 

OFFIC03 

OFFIC08 

OFFIC16 

-$1.95 -$0.18 

-$1.37 -$0.13 

$6.06 $0.56 

-$19.65 -$1.83 

-$17.07 -$1.59 

-$13.46 -$1.25 

RETAIL1 -$4.16 -$0.39 -$17.60 -$1.63 

RSTRNT1 -$3.07 -$0.29 -$38.03 -$3.53 

Table 11-13 reports the statewide changes in total energy costs by building type and 

building design, which account for one year’s worth of new construction evaluated over 

10 years of building operation. Overall, reductions in energy costs are greater for the 

more energy efficient building designs: $3.8 million and $34.3 million for adopting 

ASHRAE 90.1-2007 and LEC, respectively. The increase in energy use for the high-rise 

buildings leads to an increase in energy costs for those buildings for ASHRAE 90.1-2007. 

All building types realize energy cost savings for the LEC design. The energy cost 

savings are highly correlated with the energy use savings. 

Assuming that the buildings considered in this study, which represent 58.4 % of all new 

commercial floor space in the state, are generally representative of the entire new 

commercial building stock in the state, the results for ASHRAE 90.1-2007 and LEC can 

be extrapolated to estimate the total statewide energy cost savings of $6.5 million and 

$58.7 million over the 10-year study period, respectively. 

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Tennessee 

Table 11-13 Statewide Change in Energy Costs for One Year of Construction, 

10-Year, Tennessee 

Building Subcategory m 2 ft2 Energy Code 

Type Weighting (1000s) (1000s) 2007 LEC 

APART04 44.9 % 89 955 -$255 316 -$1 540 657
 

APART06 55.1 % 109 1169 -$268 637 -$2 102 662
 

HOTEL15 100.0 % 136 1469 $697 170 -$1 410 958 

HIGHS02 100.0 % 362 3895 -$888 648 -$7 184 973 

OFFIC03 37.4 % 172 1850 -$335 849 -$3 377 105 

OFFIC08 40.4 % 185 1995 -$253 116 -$3 164 579 

OFFIC16 22.2 % 102 1098 $618 451 -$1 373 321 

RETAIL1 100.0 % 716 7710 -$2 981 169 -$12 603 521 

RSTRNT1 100.0 % 40 429 -$122 325 -$1 515 615 

Total 1911 20 571 -$3 789 438 -$34 273 392 

Note: Dormitories are excluded because no floor area category is reported in the 

construction data. 

11.2.3 Energy-related Carbon Emissions 

Table 11-14 reports the average reduction in energy-related carbon emissions over 10 

years, per m 

2 (ft2

), by building type and building design. The carbon emissions estimation 

approach is defined in Section 5.3. 

Table 11-14 Average Per Unit Change in Carbon Emissions, 10-Year, Tennessee 

Building Energy Code 

Type 2007 

kg/m2 lb/ft2 

LEC 

kg/m2 lb/ft2 

APART04 

APART06 

-29.4 -6.0 

-25.5 -5.2 

-186.9 -38.3 

-209.5 -42.9 

DORMI04 

DORMI06 

-18.2 -3.7 

-22.9 -4.7 

-140.1 -28.7 

-219.5 -45.0 

HOTEL15 54.2 11.1 -112.6 -23.1 

HIGHS02 -23.8 -4.9 -216.7 -44.4 

OFFIC03 

OFFIC08 

OFFIC16 

-18.3 -3.7 

-12.1 -2.5 

64.8 13.3 

-209.2 -42.9 

-181.3 -37.1 

-146.5 -30.0 

RETAIL1 -39.9 -8.2 -184.6 -37.8 

RSTRNT1 -29.5 -6.0 -405.3 -83.0 

Table 11-15 applies the Table 11-14 results to one year’s worth of new building 

construction in the state to estimate statewide reduction in carbon emissions from 

adoption of more energy efficient codes. The total reduction in carbon emissions ranges 

widely across building designs, but ASHRAE 90.1-2007 and LEC decrease carbon 

emissions for the state as a whole. The adoption of ASHRAE 90.1-2007 saves 35 084 

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Tennessee 

metric tons over a 10-year study period. The adoption of the LEC design decreases 

carbon emissions by 366 027 metric tons over the 10-year study period for one year’s 

worth of new commercial construction for these building types. 

Assuming that the buildings considered in this study are generally representative of the 

entire new commercial building stock in the state, the results for the ASHRAE 90.1-2007 

and LEC designs can be extrapolated to estimate statewide reduction in carbon emissions 

of 60 076 tons and 626 759 tons over the 10-year study period, respectively. 

Table 11-15 Statewide Change in Total Carbon Emissions for One Year of 

Construction, 10-Year, Tennessee – Metric Tons 

Building Subcategory m 2 ft2 Energy Code
 

Type Weighting (1000s) (1000s) 2007 LEC
 

APART04 44.9 % 89 955 -2609 -16 580
 

APART06 55.1 % 109 1169 -2764 -22 757
 

HOTEL15 100.0 % 136 1469 7394 -15 366 

HIGHS02 100.0 % 362 3895 -8602 -78 417 

OFFIC03 37.4 % 172 1850 -3140 -35 960 

OFFIC08 40.4 % 185 1995 -2237 -33 602 

OFFIC16 22.2 % 102 1098 6607 -14 940 

RETAIL1 100.0 % 716 7710 -28 557 -132 250 

RSTRNT1 100.0 % 40 429 -1177 -16 154 

Total 1911 20 571 -35 084 -366 027 

Note: Dormitories are excluded because no floor area category is reported 

in the construction data. 

11.2.4 Life-Cycle Costs 

Table 11-16 reports the average change in life-cycle cost over 10 years, per m2 (ft2), by 

building type and building design. As discussed in Section 5.2, life-cycle costs include 

construction costs, maintenance, repair, and replacement costs, energy costs, and residual 

values. 

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Tennessee 

Table 11-16 Average Per Unit Change in Life-Cycle Costs, 10-Year, Tennessee
 

Building Energy Code 

Type 2007 

$/m2 $/ft2 

LEC 

$/m2 $/ft2 

APART04 -$3.45 -$0.32 -$0.99 -$0.09 

APART06 -$2.86 -$0.27 -$2.40 -$0.22 

DORMI04 -$6.39 -$0.59 -$9.79 -$0.91 

DORMI06 -$2.18 -$0.20 -$5.01 -$0.47 

HOTEL15 $5.47 $0.51 $7.09 $0.66 

HIGHS02 -$2.68 -$0.25 -$12.57 -$1.17 

OFFIC03 -$3.18 -$0.30 -$18.90 -$1.76 

OFFIC08 -$6.44 -$0.60 -$23.22 -$2.16 

OFFIC16 $5.66 $0.53 $5.78 $0.54 

RETAIL1 -$2.67 -$0.25 -$2.38 -$0.22 

RSTRNT1 -$11.42 -$1.06 -$96.02 -$8.92 

Table 11-17 applies the Table 11-16 results to one year’s worth of new building 

construction in the state to estimate the change in statewide life-cycle costs from adoption 

of more energy-efficient codes. ASHRAE 90.1-2007 results in total reductions in lifecycle costs of $4.4 million over the 10-year study period relative to ASHRAE 90.1-2004 

for the building types considered in this study. The LEC design leads to a decrease in 

total statewide life-cycle costs of $16.4 million, while reducing life-cycle costs for 7 of 9 

building types. The ASHRAE 90.1-2007 and the LEC designs lead to an increase in lifecycle costs for hotels and 16-story office buildings. Assuming that the buildings 

considered in this study are generally representative of the entire new commercial 

building stock in the state, the results for ASHRAE 90.1-2007 and LEC design can be 

extrapolated to estimate the total reductions in life-cycle costs of $7.5 million and $28.1 

million over the 10-year study period, respectively. 

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Tennessee 

Table 11-17 Statewide Change in Life-Cycle Costs for One Year of Construction, 

10-Year, Tennessee 

Building Subcategory m 2 ft2 Energy Code
 

Type Weighting (1000s) (1000s) 2007 LEC
 

APART04 44.9 % 89 955 -$306 372 -$87 633 

APART06 55.1 % 109 1169 -$310 942 -$260 597 

HOTEL15 100.0 % 136 1469 $747 205 $967 430 

HIGHS02 100.0 % 362 3895 -$968 977 -$4 548 170 

OFFIC03 37.4 % 172 1850 -$547 253 -$3 248 330 

OFFIC08 40.4 % 185 1995 -$1 193 900 -$4 305 144 

OFFIC16 22.2 % 102 1098 $577 169 $589 230 

RETAIL1 100.0 % 716 7710 -$1 913 574 -$1 703 531 

RSTRNT1 100.0 % 40 429 -$455 105 -$3 827 052 

Total 1911 20 571 -4 371 749 -16 423 797 

Note: Dormitories are excluded because no floor area category is reported in the 

construction data. 

11.3 State Summary 

Tennessee is one of the few states that have adopted ASHRAE 90.1-2004 as their current 

state energy code for commercial buildings. On average, adopting ASHRAE 90.1-2007 

leads to reductions in energy use, energy costs, and energy-related carbon emissions. 

Based on the average annual new construction in the state from 2003 to 2007 and a 10­

year study period, adopting ASHRAE 90.1-2007 as the state’s energy code would lead to 

energy savings of 10.1 GWh (34.4 GBtu), energy cost savings of $6.5 million, carbon 

emissions reductions of 66 072 metric tons, and life-cycle cost savings of $7.5 million. 

The life-cycle cost savings are greater than the energy cost savings. The relaxation of the 

U-factor requirement from ASHRAE 90.1-2004 to ASHRAE 90.1-2007 decreases the costs 

of construction by a greater amount than the other energy efficiency measures increase 

construction costs, while still reducing total energy costs. The LEC design would be even 

more beneficial for the state with savings of 807.8 GWh (2758.3 GBtu), energy cost 

savings of $58.7 million, and carbon emissions reductions of 689 317 metric tons while 

decreasing life-cycle costs by $28.1 million for one year’s worth of commercial building 

construction. 

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Wisconsin 

12 Wisconsin 

Wisconsin is selected for this study for three reasons. First, the state represents the 

Midwest region of the United States. Second, Wisconsin is located in the coldest climates 

in the contiguous United States. Third, Wisconsin is one of four states in this study that 

have adopted ASHRAE 90.1-2007 as its state energy code for commercial buildings, 

which allows for comparisons across states. 

Table 12-1 provides an overview of Wisconsin’s simulated energy use keyed to building 

types and energy codes. Average energy use varies across building types and building 

designs. The 8-story office building uses the least amount of energy at 93 kWh/m2 to 

111 kWh/m2 (29 kBtu/ft2 to 35 kBtu/ft2) annually. The high school uses the greatest 

amount of energy at 282 kWh/m2 to 300 kWh/m2 (90 kBtu/ft2 to 95 kBtu/ft2) annually. 

Table 12-1 Average Annual Energy Use by Building Type and Energy Code, 

Wisconsin 

Building 

Type 

Energy Code 

2007 

kWh/m2 kBtu/ft2 

LEC 

kWh/m2 kBtu/ft2 

APART04 

APART06 

189 60 

187 59 

171 54 

170 54 

DORMI04 

DORMI06 

150 48 

209 66 

132 42 

192 61 

HOTEL15 201 64 183 58 

HIGHS02 300 95 282 90 

OFFIC03 

OFFIC08 

OFFIC16 

124 39 

111 35 

183 58 

102 32 

93 29 

163 52 

RETAIL1 143 45 120 38 

RSTRNT1 191 61 146 46 

The detailed analysis for this state reports the changes in energy use, energy costs, 

energy-related carbon emissions, and life-cycle costs from adoption of a more stringent 

energy code. The results are reported in terms of average percentage savings on a 

statewide and city-by-city basis and as total savings on a statewide basis. 

12.1 Percentage Savings 

Changes in percentage terms allow for direct comparisons across building types and 

locations within a state. This section discusses the average percentage changes from 

investing in a more energy efficient design in the state of Wisconsin. 

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Wisconsin 

12.1.1 Statewide Building Comparison 

Table 12-2 shows the percentage change in energy use, energy costs, energy-related 

carbon emissions, and life-cycle costs for the LEC design relative to ASHRAE 90.1-2007. 

There is significant variation in the change in energy use for the LEC design relative to 

ASHRAE 90.1-2007, ranging from -5.9 % to -23.6 % depending on the building type with 

an overall average of -12.6 %. High schools realize the lowest reductions in energy use 

while restaurants realize the greatest reductions in energy use. 

Table 12-2 Average Percentage Change in Energy Use from Adoption of Newer 

Codes, 10-Year, Wisconsin 

Building LEC 

Type Energy Use Energy Cost Carbon LCC 

APART04 -9.5 -15.9 -16.4 0.4 

APART06 -9.3 -15.5 -16.0 0.5 

DORMI04 -12.0 -17.0 -17.4 -0.8 

DORMI06 -8.2 -13.7 -14.2 0.2 

HOTEL15 -8.9 -11.2 -11.4 0.4 

HIGHS02 -5.9 -12.7 -13.4 -1.1 

OFFIC03 -17.5 -20.1 -20.2 -1.7 

OFFIC08 -16.4 -18.0 -18.1 -1.2 

OFFIC16 -10.9 -11.9 -12.0 0.3 

RETAIL1 -15.9 -18.0 -18.1 -1.1 

RSTRNT1 -23.6 -28.7 -29.1 -3.3 

Average -12.6 -16.6 -16.9 -0.7 

There is a significant variation in the average percentage change in energy costs for the 

LEC design relative to ASHRAE 90.1-2007, ranging from -11.2 % to -28.7 % depending 

on the building type with an average of -16.6 % for 10 years of building operation. The 

energy costs are reduced by a greater percentage than energy use because the energy 

efficiency measures decrease electricity consumption by a greater percentage than natural 

gas consumption. For the high school, adopting the LEC design increases natural gas 

consumption while decreasing electricity consumption. The increase in natural gas 

consumption offsets 13.2 % of the reduction in electricity consumption, and results in the 

percentage reduction in energy costs to be over twice the percentage reduction in energy 

use. The LEC design incorporates daylighting and overhangs into the building design, 

which decreases the building’s internal and external heat gains, respectively. The shift in 

energy use from electricity to natural gas consumption to meet the greater heating loads 

decreases energy costs because natural gas is cheaper on a per unit of energy basis 

relative to electricity. 

There is significant variation in the average change in energy-related carbon emissions 

across building types for the LEC design relative to ASHRAE 90.1-2007, ranging 

from -11.4 % to -29.1 % with an average of -16.9 %. For the LEC design, the percentage 

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Wisconsin 

reduction in carbon emissions is slightly greater than the percentage reduction in energy 

use for all 11 building types because the energy efficiency measures decrease electricity 

consumption by a greater percentage than natural gas consumption. The greater relative 

reduction in electricity consumption further decreases carbon emissions because natural 

gas has a lower average carbon emissions rate than electricity. 

The percentage change in life-cycle costs varies across building types, ranging 

from -3.3 % to 0.5 % for a 10-year study period with 6 of the 11 building types realizing 

reductions in life-cycle costs. Based on the overall average percentage change of -0.7 % 

in life-cycle costs, the LEC design may be cost-effective for the state to adopt as its state 

energy code. 

12.1.2 City Comparisons 

Simulations are run for 5 cities located in Wisconsin, all located in Zone 6A: Eau Claire, 

Green Bay, La Crosse, Madison, and Milwaukee. While the selected cities are located in 

the same climate zone, the results may still vary for two reasons. First, cities within the 

same climate zone may have some variation in the local climate, which can lead to 

variation in energy consumption. Second, construction material and labor costs may vary 

significantly by locality. 

Table 12-3 shows the percentage change in energy use, energy costs, energy-related 

carbon emissions, and life-cycle costs for the LEC design relative to ASHRAE 90.1-2007 

for each city in the state. The average percentage changes in energy use for all building 

types from adopting the LEC design do not vary significantly across cities, ranging from 

-12.1 % to -12.8 % with an overall average of -12.6 %. Any variation in local climate 

appears to have minimal effects on energy consumption. 

Table 12-3 Average Percentage Change in Energy Use from Adoption of Newer 

Codes by City, 10-Year, Wisconsin 

Cities Zone LEC 

Energy Use Energy Cost Carbon LCC 

Eau Claire 6A -12.1 -16.1 -16.7 -0.7 

Green Bay 6A -12.4 -16.5 -17.1 -0.8 

La Crosse 6A -12.7 -16.6 -17.2 -0.5 

Madison 6A -12.8 -16.8 -17.3 -0.7 

Milwaukee 6A -12.8 -16.7 -17.3 -0.6 

Average -12.6 -16.6 -17.1 -0.7 

The average percentage change in energy costs for all building types also varies 

minimally across cities, ranging from -16.1 % to -16.8 % for 10 years of operation. For 

all cities, reductions in energy costs are greater than reductions in energy use because the 

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Wisconsin 

percentage reduction in electricity consumption is greater than the reduction in natural 

gas consumption. Repeating the pattern, the average percentage change in carbon 

emissions for all building types also varies minimally across cities, ranging from -16.7 % 

to -17.3 %. Reductions in life-cycle costs for all building types vary minimally across 

cities, with the percentage change ranging from -0.5 % to -0.8 %. 

12.2 Total Savings 

How much can Wisconsin save, in terms of energy use, energy costs, and carbon 

emissions, from adopting a more stringent state energy code for commercial buildings? 

What are the life-cycle costs associated with the new energy code adoption? To answer 

these questions, it is first necessary to estimate savings per unit of floor area for each 

building type in the state. 

12.2.1 Energy Use 

Table 12-4 reports the average per unit change in annual energy use by building type and 

building design in the state.27 The reduction per m2 (ft2

) is multiplied by the estimated m2 

(ft2) of new construction of each building type. Table 12-5 reports the estimated average 

annual floor area of new construction and the total annual reduction in energy use for 

each building type. The weightings within a category (e.g. small, medium, and large 

office buildings) are based on the national average percentage of new building 

construction for the category that is represented by each subcategory.28 

Table 12-4 Average Per Unit Change in Annual Energy Use, Wisconsin 

Building Energy Code 

Type LEC 

kWh/m2 kBtu/ft2 

APART04 -17.9 -5.7 

APART06 -17.4 -5.5 

DORMI04 -178.0 -5.7 

DORMI06 -17.2 -5.5 

HOTEL15 -17.8 -5.6 

HIGHS02 -21.8 -6.9 

OFFIC03 -17.6 -5.6 

OFFIC08 -18.2 -5.8 

OFFIC16 -20.0 -6.3 

RETAIL1 -22.7 -7.2 

RSTRNT1 -44.9 -14.3 

27 A simple average for a state is used because no data for a weighted average is available regarding the
 

amount of new construction on a city-by-city basis.
 

28 State-level subcategory data are not available.
 

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Wisconsin 

The adoption of the LEC design as the state’s energy code for commercial buildings 

would save energy for all building types and 28.0 GWh (95.6 GBtu) of total energy use 

annually for one year’s worth of new construction for these building types. Assuming that 

the buildings considered in this study, which represent 57.0 % of all new commercial 

floor space in the state, are generally representative of the entire new commercial 

building stock in the state, the results can be extrapolated to estimate statewide savings to 

be 49.1 GWh (167.6 GBtu) per year. These savings imply 491.0 GWh (1676.3 GBtu) in 

energy savings over the 10-year study period. 

The change in energy use varies across building types. The building types that have the 

greatest percentage reductions are not always the same buildings that lead to the greatest 

total reductions for the state. Instead the building types that represent a greater amount of 

new floor area realize the largest changes in energy use. For example, the building types 

that lead to the greatest estimated reductions in energy use for the LEC design -- retail 

stores and high schools -- only rank 4th and 11th in percentage reduction, respectively, 

among the 11 building types, as reported in Table 12-2. 

Table 12-5 Statewide Change in Annual Energy Use for One Year of Construction, 

Wisconsin 

Building Subcategory m 2 ft2 Energy Code 

Type Weighting (1000s) (1000s) LEC 

kWh kBtu 

APART04 44.9 % 81 877 -1 460 482 -4 986 715
 

APART06 55.1 % 100 1074 -1 733 043 -5 917 355
 

HOTEL15 100.0 % 117 1255 -2 069 204 -7 065 153 

HIGHS02 100.0 % 226 2430 -3 977 568 -13 581 126 

OFFIC03 37.4 % 117 1254 -2 534 616 -8 654 268 

OFFIC08 40.4 % 126 1352 -2 279 698 -7 783 868 

OFFIC16 22.2 % 69 744 -1 382 125 -4 719 170 

RETAIL1 100.0 % 498 5359 -11 317 290 -38 642 095 

RSTRNT1 100.0 % 27 295 -1 230 620 -4 201 865 

Total 1360 14 639 -27 984 646 -95 551 615 

Note: Dormitories are excluded because no floor area category is reported in 

the construction data. 

12.2.2 Energy Costs 

Table 12-6 reports the average per unit change in energy costs by building type for the 

LEC design. Energy costs are calculated using the annual energy use, state average 

energy cost rates, and regional energy price escalation rates as defined in Section 3.2. 

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Wisconsin 

Table 12-6 Average Per Unit Change in Energy Costs, 10-Year, Wisconsin
 

Building Energy Code 

Type LEC 

$/m2 $/ft2 

APART04 -$13.26 -$1.23 

APART06 -$12.99 -$1.21 

DORMI04 -$11.46 -$1.06 

DORMI06 -$12.68 -$1.18 

HOTEL15 -$10.13 -$0.94 

HIGHS02 -$15.17 -$1.41 

OFFIC03 -$14.99 -$1.39 

OFFIC08 -$13.00 -$1.21 

OFFIC16 -$12.09 -$1.12 

RETAIL1 -$13.91 -$1.29 

RSTRNT1 -$29.49 -$2.74 

Table 12-7 reports the statewide changes in total energy costs by building type and 

building design, which account for one year’s worth of new construction evaluated over 

10 years. All building types realize energy cost savings for the LEC design, with 

statewide reductions in energy costs of $18.9 million for 10 years of building operation. 

Assuming that the buildings considered in this study, which represent 57.0 % of all new 

commercial floor space in the state, are generally representative of the entire new 

commercial building stock in the state, the results for the LEC design can be extrapolated 

to estimate the total statewide energy cost savings of $33.2 million over the 10-year study 

period. 

Table 12-7 Statewide Change in Energy Costs for One Year of Construction, 

10-Year, Wisconsin 

Building Subcategory m 2 ft2 Energy Code
 

Type Weighting (1000s) (1000s)
 LEC 

APART04 44.9 % 81 877 -$1 079 803 

APART06 55.1 % 100 1074 -$1 296 271 

HOTEL15 100.0 % 117 1255 -$1 180 194 

HIGHS02 100.0 % 226 2430 -$3 425 643 

OFFIC03 37.4 % 117 1254 -$1 745 771 

OFFIC08 40.4 % 126 1352 -$1 633 430 

OFFIC16 22.2 % 69 744 -$835 570 

RETAIL1 100.0 % 498 5359 -$6 923 358 

RSTRNT1 100.0 % 27 295 -$807 577 

Total 1360 14 639 -$18 927 617 

Note: Dormitories are excluded because no floor area category is 

reported in the construction data. 

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Wisconsin 

12.2.3 Energy-related Carbon Emissions 

Table 12-8 reports the average reduction in energy-related carbon emissions over 10 

years, per m 2 (ft2

), by building type. The carbon emissions estimation approach is defined 

in Section 5.3. 

Table 12-8 Average Per Unit Change in Carbon Emissions, 10-Year, Wisconsin 

Building Energy Code 

Type LEC 

kg/m2 lb/ft2 

APART04 -153.9 -31.5 

APART06 -150.9 -30.9 

DORMI04 -131.9 -27.0 

DORMI06 -147.2 -30.2 

HOTEL15 -115.8 -23.7 

HIGHS02 -177.4 -36.3 

OFFIC03 -173.3 -35.5 

OFFIC08 -150.7 -30.9 

OFFIC16 -138.8 -28.4 

RETAIL1 -159.7 -32.7 

RSTRNT1 -340.1 -69.7 

Table 12-9 applies the Table 12-8 results to one year’s worth of new building 

construction in the state to estimate statewide reduction in carbon emissions from 

adoption of more energy efficient codes. The total reduction in carbon emissions ranges 

widely across building designs and is highly correlated with total reduction in energy use. 

The LEC design decreases carbon emissions for all building types. The adoption of the 

LEC design results in savings of 218 699 metric tons over the 10-year study period for 

one year’s worth of new commercial construction for these building types. Assuming that 

the buildings considered in this study are generally representative of the entire new 

commercial building stock in the state, the results for the LEC design can be extrapolated 

to estimate statewide reductions in carbon emissions of 383 682 metric tons over the 10­

year study period. 

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Wisconsin 

Table 12-9 Statewide Change in Total Carbon Emissions for One Year of 

Construction, 10-Year, Wisconsin – Metric Tons 

Building Subcategory m 2 ft2 Energy Code
 

Type Weighting (1000s) (1000s)
 LEC 

APART04 44.9 % 81 877 -12 536 

APART06 55.1 % 100 1074 -15 055 

HOTEL15 100.0 % 117 1255 -13 501 

HIGHS02 100.0 % 226 2430 -40 043 

OFFIC03 37.4 % 117 1254 -20 191 

OFFIC08 40.4 % 126 1352 -18 927 

OFFIC16 22.2 % 69 744 -9591 

RETAIL1 100.0 % 498 5359 -79 534 

RSTRNT1 100.0 % 27 295 -9321 

Total 1360 14 639 -218 699 

Note: Dormitories are excluded because no floor area category is 

reported in the construction data. 

12.2.4 Life-Cycle Costs 

Table 12-10 reports the average change in life-cycle cost over 10 years, per m2 (ft2), by 

building type. As discussed in Section 5.2, life-cycle costs include construction costs, 

maintenance, repair, and replacement costs, energy costs, and residual values. 

Table 12-10 Average Per Unit Change in Life-Cycle Costs, 10-Year, Wisconsin 

Building Energy Code 

Type LEC 

$/m2 $/ft2 

APART04 $4.42 $0.41 

APART06 $5.20 $0.48 

DORMI04 -$8.05 -$0.75 

DORMI06 $2.48 $0.23 

HOTEL15 $3.87 $0.36 

HIGHS02 -$9.40 -$0.87 

OFFIC03 -$13.92 -$1.29 

OFFIC08 -$10.53 -$0.98 

OFFIC16 $2.76 $0.26 

RETAIL1 -$7.40 -$0.69 

RSTRNT1 -$45.18 -$4.20 

Table 12-11 applies the Table 12-10 results to one year’s worth of new building 

construction in the state to estimate statewide life-cycle cost changes from adoption of 

the more energy-efficient code. Total changes in life-cycle costs over the 10-year study 

period vary across building type, with 5 of 9 building types realizing reductions in lifecycle costs. Overall, the LEC design results in a decrease of $8.5 million in statewide 

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Wisconsin 

life-cycle costs relative to ASHRAE 90.1-2007. The 6-story apartment buildings and 

hotels realize the greatest statewide increase in life-cycle costs ($518 369 and $450 877, 

respectively) while retail stores realize the greatest decrease in life-cycle costs 

($3.7 million). Assuming that the buildings considered in this study are generally 

representative of the entire new commercial building stock in the state, the results for the 

LEC design can be extrapolated to estimate a statewide life-cycle cost decrease of $14.9 

million over the 10-year study period. 

Table 12-11 Statewide Change in Life-Cycle Costs for One Year of Construction, 

10-Year, Wisconsin 

Building Subcategory m 2 ft2 Energy Code
 

Type Weighting (1000s) (1000s) LEC
 

APART04 44.9 % 81 877 $359 919 

APART06 55.1 % 100 1074 $518 369 

HOTEL15 100.0 % 117 1255 $450 877 

HIGHS02 100.0 % 226 2430 -$2 122 267 

OFFIC03 37.4 % 117 1254 -$1 621 064 

OFFIC08 40.4 % 126 1352 -$1 322 856 

OFFIC16 22.2 % 69 744 $191 013 

RETAIL1 100.0 % 498 5359 -$3 684 303 

RSTRNT1 100.0 % 27 295 -$1 237 360 

Total 1360 14 639 -$8 467 672 

Note: Dormitories are excluded because no floor area category is 

reported in the construction data. 

12.3 State Summary 

Wisconsin is one of the states that adopted ASHRAE 90.1-2007 as its state commercial 

building energy code. On average, adopting the LEC design reduces energy use, energy 

costs and energy-related carbon emissions, but not in a cost-effective manner. Based on 

the average annual new construction in the state from 2003 to 2007 and a 10-year study 

period, adopting the LEC design as the state’s energy code for commercial buildings 

would lead to statewide energy savings of 491.0 GWh (1676.3 GBtu), energy cost 

savings of $33.2 million, and carbon emissions reductions of 383 682 metric tons while 

decreasing life-cycle costs by $14.8 million for one year’s worth of commercial building 

construction. 

105
 
Wisconsin 

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Total Savings Comparisons for Selected States 

13 Total Savings Comparisons for Selected States 

By comparing the aggregate results from the detailed state-by-state analysis, some 

interesting trends emerge. Table 13-1 shows the total savings in energy use, energy costs, 

life-cycle costs, and carbon emissions from adopting the LEC design as the commercial 

building energy code for each of the 7 representative states for a 10-year study period. In 

general, there is a strong correlation among energy use and energy costs, life-cycle costs, 

and carbon emissions. However, there are a number of factors that lead to significant 

variation in relative savings, including current state energy code requirements, newly 

constructed building stock mix and size, climate zone, electricity costs, and energy 

production fuel mix. 

Table 13-1 Total Reductions by State for Adoption of the LEC Design, 10-Year 

State Code 

Floor 

Area 

Ranking 

Average Annual 

New Floor Area 

1000 m2 (1000 ft2

) 

Energy 

Use 

(GWh) 

Energy 

Costs 

($million) 

Carbon 

(1000 tCO2e) 

LCC 

($million) 

AK None 46 290 (3116) 99.4 9.8 58.4 2.4 

CO 2001 17 3292 (35 437) 1112.9 72.7 1126.2 59.7 

FL 2007 1 16 542 (178 061) 3790.5 333.0 3230.2 151.3 

MD 2007 16 3385 (36 433) 622.2 62.4 448.9 28.8 

OR 2007 27 1745 (18 788) 261.4 17.4 146.1 -0.4 

TN 2004 18 3272 (35 219) 807.8 58.7 626.8 28.1 

WI 2007 22 2386 (25 679) 491.0 33.2 383.7 14.8 

Total energy savings varies across states for a number of reasons. First, states with more 

newly constructed commercial floor area realize greater reductions in energy use. 

Second, states located in warmer climate zones realize greater reductions in energy use 

than the states located in colder climate zones because the buildings located in warmer 

climate zones benefit more from the overhangs and daylighting installed in the LEC 

design. Third, a state’s current state energy code for commercial buildings drives the 

variation in energy use. Consider the reductions in energy use for two states with similar 

amounts of new floor area, Colorado and Maryland. Even though Maryland has slightly 

more new floor area construction and a warmer climate, Colorado realizes 79 % more 

reductions in energy use. Colorado has adopted ASHRAE 90.1-2001 as its state energy 

code for commercial buildings while Maryland has adopted ASHRAE 90.1-2007. The 

newer edition of ASHRAE 90.1 leads to less energy savings potential than the older 

standard edition. 

Table 13-3 shows the reduction in energy use per unit of newly constructed floor area by 

state. Alaska realizes the greatest reduction in energy use per unit of floor area followed 

by Colorado while Florida is 4th out of the 7 states considered in this study. These results 

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Total Savings Comparisons for Selected States 

vary significantly from the total reductions in energy use, where Florida is first 

(3790 GWh), Colorado is a distant second (1113 GWh), and Alaska is last (99 GWh). 

The three states that have not yet adopted ASHRAE 90.1-2007 realize the greatest total 

reductions in energy use per unit of newly constructed floor area. 

Table 13-2 Energy Use Reduction per Unit of Floor Area for Adoption of the LEC 

Design by State, 10-Year 

State Code 

Floor 

Area 

Average Annual 

New Floor Area 

Energy Use Reduction 

Ranking 1000 m2 (1000 ft2

) GWh kWh/m2 kBtu/ft2 

AK None 46 290 (3116) 99.4 343 109 

CO 2001 17 3292 (35 437) 1112.9 338 107 

TN 2004 18 3272 (35 219) 807.8 247 78 

FL 2007 1 16 542 (178 061) 3790.5 229 73 

WI 2007 22 2386 (25 679) 491.0 206 65 

MD 2007 16 3385 (36 433) 622.2 184 58 

OR 2007 27 1745 (18 788) 261.4 150 48 

In general, the states that realize the greatest reductions in energy use also realize the 

greatest reductions in energy costs. However, reductions in energy costs are also 

impacted by the per unit energy cost of electricity and natural gas and the energy source 

fuel mix of reductions in energy use by the buildings in a state. Table 13-3 shows each 

state’s natural gas rate, electricity rate, weighted average fraction of the reduction in 

electricity consumption offset by the change in natural gas consumption, and average 

reduction in energy costs from adopting the LEC design.29 States with the highest 

electricity rates tend to realize the greatest reductions in energy costs per unit of reduction 

in energy use. Relative to electricity prices, natural gas prices are fairly constant across 

states and are always cheaper than natural gas per unit of energy. Other than a state’s 

energy prices, the most important factor is the fraction of total reductions in electricity 

consumption offset by a change in natural gas consumption. There is some minor 

fluctuation in the results due to the regional energy price escalation rates used to estimate 

changes in price levels in the future. 

29 The fraction of electricity offset by natural gas consumption is greater (less) than 100 % (-100 %) when 

natural gas consumption increases (decreases) by a greater amount than electricity consumption decreases. 

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Total Savings Comparisons for Selected States 

Table 13-3 Energy Cost Reduction per kWh of Energy Use Reduction for Adoption 

of the LEC Design by State, 10-Year 

State Code Offset* 

(%) 

Electricity 

Rate 

($/kWh) 

Natural Gas 

Rate 

($/kWh) 

Energy Cost 

Reduction 

($/kWh) 

AK None -24.9 14.5 2.8 0.10 

MD 2007 13.3 12.0 3.2 0.10 

FL 2007 4.0 10.8 3.2 0.09 

TN 2004 -9.4 9.6 3.1 0.07 

WI 2007 -25.9 9.6 2.6 0.07 

CO 2001 8.6 8.2 2.2 0.07 

OR 2007 18.8 7.5 3.5 0.07 

*Percentage of the reduction in electricity consumption offset by change in 

natural gas consumption. 

Table 13-4 shows the reduction in cradle-to-grave energy-related carbon emissions per 

unit of reduction in energy use, the CO2e emissions rate for electricity and natural gas 

generation, and the weighted average fraction of the reduction in electricity consumption 

offset by a change in natural gas consumption. There is a direct correlation between the 

CO2e emissions rate for electricity generation in a state and the reduction in carbon 

emissions per unit of reduction in energy use. However, the correlation is not perfect. 

Florida realizes greater reductions per unit of energy than Wisconsin even though its 

electricity carbon emissions rate is relatively smaller, because Florida’s offset reflects an 

increase in natural gas consumption while Wisconsin’s reflects a decrease. 

Table 13-4 Carbon Reduction per GWh of Energy Use Reduction for Adoption of 

the LEC Design by State, 10-Year 

State Code Offset* 

(%) 

CO2e 

Emissions Rate 

for Electricity 

(t/GWh) 

CO2e 

Emissions Rate 

for Natural Gas 

(t/GWh) 

CO2e 

Reduction 

(t/GWh) 

CO 2001 8.6 994 241 1012 

FL 2007 4.0 826 241 852 

WI 2007 -25.9 905 241 781 

TN 2004 -9.4 819 241 776 

MD 2007 13.3 652 241 722 

AK None -24.9 663 241 588 

OR 2007 18.8 494 241 559 

*Percentage of the reduction in electricity consumption offset by change in natural 

gas consumption. 

The relative life-cycle cost reduction per unit of new floor area is shown in Table 13-5. 

There is a correlation between the energy use savings and the life-cycle cost-effectiveness 

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Total Savings Comparisons for Selected States 

of adopting the LEC design. Colorado realizes the greatest reductions per unit of floor 

area for both energy use and life-cycle costs for a 10-year study period. Meanwhile, 

Oregon realizes the smallest reductions in energy use per unit of floor area and is the only 

state to realize an increase in life-cycle costs for a 10-year study period. The life-cycle 

cost savings per unit of floor area does not have a strong correlation with the current 

energy code adopted in a state. Additional factors, such as climate zone, local 

construction costs, electricity and natural gas rates, fuel mix, and building stock mix, 

must also be influencing the life-cycle cost-effectiveness of adopting the LEC design. 

Table 13-5 Life-Cycle Cost Reductions per Unit of New Floor Area for Adoption of 

the LEC Design by State, 10-Year 

State Code 

Floor 

Area kWh/m2 

LCC Reduction 

Ranking $million $/m2 $/ft2 

CO 2001 17 338 59.7 18.13 1.68 

FL 2007 1 229 151.3 9.15 0.85 

TN 2004 18 247 28.1 8.59 0.80 

MD 2007 16 184 28.8 8.51 0.79 

AK 1999 46 343 2.4 8.29 0.77 

WI 2007 22 206 14.8 6.20 0.58 

OR 2007 27 150 -0.4 -0.23 -0.02 

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Savings from Nationwide Adoption of Low Energy Case 

14 Savings from Nationwide Adoption of Low Energy Case 

One purpose of this study is to determine which states could benefit the most from 

adopting a more stringent state energy code for commercial buildings. This section 

analyzes benefits from nationwide adoption of the LEC design relative to the current 

collection of state energy codes. Benefits are evaluated across several dimensions: 

geography (state and climate zone), time, and building type. 

It would be expected that states with energy codes based on older editions of ASHRAE 

90.1, or no energy code at all, would realize greater benefits from adopting the LEC 

design because buildings in those states are expected to be built in a less energy efficient 

manner. Figure 14-1 shows the 14 states with energy codes based on older editions of 

ASHRAE 90.1 (-1999, -2001, or no energy code).30 Many of the central U.S. states have 

adopted older energy standard editions, as have a few states in the south, West Virginia, 

Arizona, Maine, and Alaska. 

Figure 14-1 States that have Adopted ASHRAE 90.1-2001 or No Energy Code 

As in the state-by-state analysis of benefits from adopting the LEC design, it is necessary 

to assume a particular study period length because energy costs fluctuate on an annual 

basis. A 10-year study period is used as the baseline because it is one of the most realistic 

investor time horizons out of the 9 study period length options in BIRDS. The 

significance of the study period length will be tested in Section 14.2. 

14.1 State Comparisons 

State benefit comparisons are made based on the simple average changes for the cities 

analyzed in each state by building type. One building type is chosen to illustrate the 

detailed analysis possible with the powerful BIRDS database compiled for this study. 

Energy use, energy costs, life-cycle costs, and cradle-to-grave energy-related carbon 

emissions are analyzed for the most common existing building type, small office 

30 All maps are generated in ArcMap 10.1. 

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Savings from Nationwide Adoption of Low Energy Case 

buildings. Summary results for the other 10 building types are reported in Table B-1 

through Table B-10 in the Appendix B. No states have adopted the LEC design so all 

should realize impacts across the four metrics listed above. 

14.1.1 3-Story Office Building 

Table 14-1 summaries the percentage changes in energy use, energy costs, life-cycle 

costs, and carbon emissions for the 3-story office building. On average, adoption of the 

LEC design for a 3-story office building decreases energy use, energy costs, and energyrelated carbon emissions by more than 20 % each while reducing life-cycle costs. 

Table 14-1 Average Percentage Change by State, 3-Story Office Building, 10-Year 

State Percentage Change State Percentage Change 

Energy Energy Carbon LCC Energy Energy Carbon LCC 

Use Cost Use Cost 

AK -25.5 -27.6 -26.9 -0.5 MT -18.0 -20.1 -19.9 -1.9 

AL -36.3 -36.6 -36.8 -0.7 NC -21.9 -23.3 -23.7 -2.1 

AR -30.4 -33.0 -33.9 -3.8 ND -29.5 -30.5 -30.6 0.8 

AZ -34.7 -34.9 -35.0 -3.1 NE -18.2 -23.0 -23.5 -2.3 

CA -24.5 -25.5 -25.1 -3.0 NH -18.1 -20.4 -20.1 -2.8 

CO -29.3 -32.1 -32.4 -5.5 NJ -19.6 -23.6 -22.9 -2.5 

CT -17.9 -23.4 -21.8 -3.1 NM -23.3 -25.5 -25.6 -3.1 

DE -20.0 -22.7 -23.2 -3.4 NV -25.3 -26.7 -26.3 -4.3 

FL -24.0 -24.3 -24.3 -2.3 NY -16.9 -22.0 -20.2 -3.0 

GA -21.6 -22.9 -23.3 -1.2 OH -17.5 -22.1 -22.7 -2.5 

HI -28.0 -28.0 -28.0 -5.7 OK -30.8 -33.7 -35.7 2.0 

IA -17.7 -21.4 -21.9 -1.7 OR -21.2 -23.5 -23.6 -3.5 

ID -19.7 -22.0 -22.1 -2.7 PA -17.5 -21.5 -22.1 -2.7 

IL -17.5 -23.0 -23.0 -2.4 RI -18.5 -22.5 -22.3 -2.8 

IN -18.3 -22.4 -23.0 -2.1 SC -23.8 -24.9 -25.0 -2.0 

KS -31.9 -34.3 -35.1 0.7 SD -28.1 -30.2 -30.4 -0.7 

KY -19.8 -22.4 -23.5 -2.4 TN -25.3 -25.8 -25.9 -2.6 

LA -21.9 -22.7 -23.0 -0.3 TX -21.7 -23.1 -23.1 -1.9 

MA -17.6 -22.8 -21.8 -2.6 UT -20.8 -24.6 -23.7 -3.0 

MD -20.0 -23.4 -23.1 -3.0 VA -22.1 -24.1 -24.5 -2.2 

ME -31.1 -31.6 -31.6 -0.7 VT -17.6 -20.1 -19.8 -2.6 

MI -16.4 -21.0 -21.5 -2.6 WA -19.6 -21.9 -22.4 -2.7 

MN -26.1 -23.7 -23.4 -1.8 WI -17.5 -20.1 -20.2 -1.7 

MO -31.6 -33.4 -34.4 1.4 WV -30.4 -31.4 -32.4 -4.3 

MS -41.9 -39.1 -39.0 0.4 WY -30.1 -31.8 -31.8 0.3 

Avg. -23.0 -25.2 -25.3 -2.2 

These detailed results can be readily analyzed in mappings of the United States. Figure 

14-2, Figure 14-3, Figure 14-5, and Figure 14-4 overlay Figure 14-1 and display the 

average percentage energy savings, energy cost savings, life-cycle cost savings, and 

carbon emissions reduction for a 10-year study period by state, respectively. The states 

with codes based on older editions of ASHRAE 90.1, or no energy code at all, are shown 

with cross hatching and bolded state borders. Figure 14-2 shows that 31 of 50 states 

realize energy use savings of 20 % or more by adopting the LEC design over their current 

state energy code. Many of the states that realize the greatest energy use savings are the 

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Savings from Nationwide Adoption of Low Energy Case 

ones that currently have energy codes based on older editions of ASHRAE 90.1, or no 

energy code at all. Of the 18 states that realize energy use savings of at least 25 %, 14 are 

states with either no energy code or a code based on ASHRAE 90.1-1999 or ASHRAE 

90.1-2001, including all 10 states that realize energy use savings of more than 30 %. 

Figure 14-2 Average Energy Use Savings by State, 3-Story Office Building, 10-Year 

Figure 14-3 overlays Figure 14-1 with the average energy cost savings over 10 years by 

state from adopting the LEC design in small office buildings. Every state reduces energy 

costs by at least 20 %. The states that currently have no energy code or energy codes 

based on older editions of ASHRAE 90.1 realize the greatest energy cost savings, with all 

13 states realizing savings of greater than 30 %. Of the 19 states that have cost savings 

greater than 25 %, 18 have adopted no state energy code, ASHRAE 90.1-1999, -2001, or ­

2004. 

Figure 14-3 Average Energy Cost Savings by State, 3-Story Office Building, 

10-Year 

Figure 14-4 overlays Figure 14-1 with the average reduction in energy-related carbon 

emissions by state from adopting the LEC design. Only two states, Vermont and 

Montana, do not reduce carbon emissions by at least 20 %. The states that currently have 

no energy code or energy codes based on older editions of ASHRAE 90.1 realize the 

greatest reduction in carbon emissions, with all 14 states realizing savings of greater than 

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Savings from Nationwide Adoption of Low Energy Case 

25 % and all but Alaska realizing savings of greater than 30 %. None of the states that 

have adopted ASHRAE 90.1-2004 or -2007 realize reductions in carbon emissions of 

greater than 30 %. 

Figure 14-4 Average Energy-related Carbon Emissions Reduction by State, 3-Story 

Office Building, 10-year 

Figure 14-5 overlays Figure 14-1 with the average life-cycle cost savings over 10 years 

by state from adopting the LEC design. The resulting map shows two interesting trends. 

First, all states that realize an increase in life-cycle costs as a result of adopting the LEC 

design as its state energy code currently have no state energy code or have adopted an 

older edition of ASHRAE 90.1. The energy cost savings of the more efficient LEC design 

are not enough to overwhelm the additional construction and MRR costs associated with 

the required energy efficiency measures. Second, states located in the central and 

southern U.S. tend to realize life-cycle cost savings less than 2 %. States located in the 

West and Northeast U.S. tend to realize life-cycle cost savings greater than 2 %. The 

energy cost savings may be greater in the west and northeast due to higher energy prices. 

Figure 14-5 Average Life-Cycle Cost Savings by State, 3-Story Office Building,
 

10-Year
 

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Savings from Nationwide Adoption of Low Energy Case 

For a 3-story office building and a 10-year study period, states that currently have no 

energy code or energy codes based on older editions of ASHRAE 90.1 have the most to 

gain in percentage terms in energy use, energy cost, and carbon emissions savings from 

adopting more stringent state energy codes. However, these same states realize an 

average increase in life-cycle costs over the same 10-year study period, raising questions 

as to the cost-effectiveness of these additional energy efficiency measures. 

14.2 Results by Study Period Length 

The nationwide analysis up to this point has focused on 3-story office buildings over a 

10-year study period. It is important to consider how the study period length – 

representing the time horizon of the investor -- impacts energy use, energy costs, energyrelated carbon emissions, and life-cycle costs. Nine study period lengths are analyzed: 1 

year, 5 years, 10 years, 15 years, 20 years, 25 years, 30 years, 35 years, and 40 years. All 

building types are included in this analysis. 

Average reduction in energy use from adoption of the LEC design is constant over all 

study period lengths because energy efficiency is assumed to be constant over time. The 

national average reduction in energy use across all cities in the study ranges from -10.6 % 

to -30.7 %, depending on the building type, with an overall national average of -17.8 %. 

Table 14-2 shows these results. 

Table 14-2 Nationwide Average Percentage Change in Energy Use by Building 

Type 

Building 

Type 

Percentage 

Change 

APART04 

APART06 

DORMI04 

DORMI06 

HOTEL15 

HIGHS02 

OFFIC03 

OFFIC08 

OFFIC16 

RETAIL1 

RSTRNT1 

Average 

-14.8 

-15.6 

-16.9 

-15.2 

-13.9 

-10.6 

-23.0 

-21.5 

-15.3 

-18.9 

-30.7 

-17.8 

As shown in Table 14-3, reductions in energy costs vary slightly, in percentage terms, 

over increasing study period lengths. The national average reduction in energy costs 

across all location-building type combinations changes from -22.8 % for a 1-year study 

period to -22.3 % for a 40-year study period. The minor variation is a result of the 

escalation rates used to adjust future energy prices, which vary by Census Region. The 

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Savings from Nationwide Adoption of Low Energy Case 

national average reduction ranges from -17.4 % to -35.6 %, depending on the building 

type and study period. 

Table 14-3 Nationwide Average Percentage Change in Energy Costs by Building 

Type and Study Period Length 

Building Study Period Length 

Type 1 5 10 15 20 25 30 35 40 

APART04 -21.5 -21.3 -21.2 -21.1 -21.0 -21.0 -20.9 -20.8 -20.7 

APART06 -23.2 -23.0 -22.9 -22.8 -22.7 -22.6 -22.5 -22.4 -22.4 

DORMI04 -22.4 -22.3 -22.2 -22.1 -22.1 -22.0 -21.9 -21.9 -21.8 

DORMI06 -22.7 -22.5 -22.4 -22.3 -22.2 -22.1 -22.0 -22.0 -21.9 

HOTEL15 -19.8 -19.6 -19.6 -19.5 -19.4 -19.3 -19.3 -19.2 -19.2 

HIGHS02 -18.3 -18.1 -18.0 -17.9 -17.8 -17.7 -17.6 -17.5 -17.4 

OFFIC03 -25.3 -25.2 -25.2 -25.2 -25.2 -25.2 -25.1 -25.1 -25.1 

OFFIC08 -22.8 -22.8 -22.8 -22.8 -22.8 -22.8 -22.7 -22.7 -22.7 

OFFIC16 -18.4 -18.4 -18.3 -18.3 -18.3 -18.2 -18.2 -18.2 -18.1 

RETAIL1 -20.9 -20.9 -20.9 -20.9 -20.8 -20.8 -20.8 -20.8 -20.8 

RSTRNT1 -35.6 -35.5 -35.4 -35.3 -35.3 -35.2 -35.2 -35.1 -35.1 

Average -22.8 -22.7 -22.6 -22.6 -22.5 -22.5 -22.4 -22.3 -22.3 

Since the national average reduction in energy use across all location-building type 

combinations is constant over all study periods, the average energy-related carbon 

emissions are also assumed constant at -22.9 %.31 The national average reduction in 

carbon emissions ranges from -18.5 % to -35.6 % depending on the building type, as 

shown in Table 14-4. 

Table 14-4 Nationwide Average Percentage Change in Carbon Emissions by 

Building Type 

Building Percentage 

Type Change 

APART04 -21.6 

APART06 -23.3 

DORMI04 -22.6 

DORMI06 -22.8 

HOTEL15 -20.0 

HIGHS02 -18.5 

OFFIC03 -25.3 

OFFIC08 -22.8 

OFFIC16 -18.5 

RETAIL1 -21.0 

RSTRNT1 -35.6 

Average -22.9 

31 Electricity fuel mixes are assumed to be fixed over all study periods. 

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Table 14-5 shows that the nationwide average percentage change in life-cycle costs varies 

significantly over increasing study period lengths, with the average change across all 

location-building type combinations ranging from -3.8 % to -1.1 %. 

Table 14-5 National Average Percentage Change in Life-Cycle Costs by Building 

Type and Study Period Length 

Building Study Period Length 

Type 1 5 10 15 20 25 30 35 40 

APART04 -1.1 0.0 -0.1 -0.5 -0.4 -0.5 -0.7 -0.8 -0.7 

APART06 -0.1 0.1 -0.2 -0.6 -0.6 -0.7 -0.9 -1.1 -1.0 

DORMI04 -7.0 -1.6 -1.2 -1.5 -1.3 -1.4 -1.5 -1.6 -1.5 

DORMI06 0.5 -0.3 -0.6 -1.1 -1.0 -1.2 -1.4 -1.6 -1.5 

HOTEL15 1.4 0.3 -0.1 -0.6 -0.7 -1.0 -1.2 -1.4 -1.4 

HIGHS02 -1.5 -1.2 -1.3 -1.6 -1.6 -1.8 -2.0 -2.2 -2.1 

OFFIC03 -10.1 -2.7 -2.2 -2.4 -2.1 -2.3 -2.4 -2.6 -2.5 

OFFIC08 -4.1 -2.2 -2.1 -2.5 -2.2 -2.4 -2.5 -2.7 -2.6 

OFFIC16 2.1 0.8 0.3 -0.4 -0.4 -0.7 -1.0 -1.2 -1.2 

RETAIL1 -9.1 -0.3 -0.1 -0.6 -0.3 -0.5 -0.8 -0.9 -0.8 

RSTRNT1 -12.2 -5.2 -4.2 -5.0 -4.7 -5.0 -5.3 -5.4 -5.4 

Average -3.8 -1.1 -1.1 -1.5 -1.4 -1.6 -1.8 -1.9 -1.9 

Figure 14-6 shows the graphical representation of the national average change in lifecycle costs by building type. For a 1-year study period, the average percentage change in 

life-cycle costs ranges from -12.2 % to 2.1 % depending on the building type. The 

significant variation is driven by the residual value of the building and its components. 

Since the study period is only one year, the residual values are almost as large as the first 

costs of building construction, amplifying even minor variations in life-cycle costs. 

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Savings from Nationwide Adoption of Low Energy Case 

Average Percentage Change in LCC
 

2.0 

0.0 

-2.0 

-4.0 

-6.0 

-8.0 

-10.0 

-12.0 

-14.0 

1 5 10 15 20 25 30 35 40
 

APART04 

APART06 

DORMI04 

DORMI06 

HOTEL15 

HIGHS02 

OFFIC03 

OFFIC08 

OFFIC16 

RETAIL1 

RSTRNT1 

Study Period
 

Figure 14-6 Nationwide Average Percentage Change in Life-cycle Costs from 

Nationwide Adoption of the LEC Design by Building Type and Study Period Length 

From the 1-year to 10-year study period, there is a convergence towards zero followed by 

a slow but steady decrease from a 10-year to a 40-year study period. For building types 

that are not cost-effective for a 1-year study period slowly become cost-effective as the 

study period length increases. Building types that are cost-effective for a 1- year study 

period remain cost-effective for all longer study period lengths. All building types are 

cost-effective for study periods lengths of 15 years or greater. 

14.3 Results by Building Type 

Table 14-6 shows the simple average changes by building type, in percentage terms, from 

adopting the LEC design for a 10-year study period. The restaurant realizes the greatest 

reductions while the high school realizes the smallest reductions in energy use, energy 

cost, and energy-related carbon emissions. 

The occupant activity is the primary driver of the results for the high school, which is 

heavily occupied during the school year and lightly occupied during the summer months. 

Some of the energy efficiency measures decrease heat gains, which lead to lower cooling 

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loads during warmer months and greater heating loads during the colder months. A 

significant portion of the reductions in electricity consumption during these colder 

months is offset by increases in natural gas consumption required to meet the increased 

heating loads. Thus, a greater portion of the high school’s energy use occurs during the 

colder months relative to other building types. The combination of more energy use 

occurring during the colder months and the offsetting increase in natural gas consumption 

during those months leads to a smaller overall percentage reduction in energy use for 

high schools. 

One of the reasons that the restaurant realizes the greatest reductions in energy use is that 

the restaurant has the smallest plug and process loads in terms of watts per unit of floor 

area. Since the plug and process load is the only electricity use not impacted by the 

energy efficiency measures adopted in this study, a greater fraction of energy use can be 

decreased for restaurants relative to the other building types. 

The restaurant realizes the greatest life-cycle cost savings while the 16-story office 

building is the only building to realize an increase in life-cycle costs, on average. Overall, 

all buildings realize significant reductions in energy use, energy costs, and carbon 

emissions. 

Table 14-6 Nationwide Average Percentage Change for LEC by Building Type, 

10-Year 

Building Percentage Change 

Type Energy Use Energy Cost Carbon LCC 

APART04 -14.8 -21.2 -21.6 -0.1 

APART06 -15.6 -22.9 -23.3 -0.2 

DORMI04 -16.9 -22.2 -22.6 -1.2 

DORMI06 -15.2 -22.4 -22.8 -0.6 

HOTEL15 -13.9 -19.6 -20.0 -0.1 

HIGHS02 -10.6 -18.0 -18.5 -1.3 

OFFIC03 -23.0 -25.2 -25.3 -2.2 

OFFIC08 -21.5 -22.8 -22.8 -2.1 

OFFIC16 -15.3 -18.3 -18.5 0.3 

RETAIL1 -18.9 -20.9 -21.0 -0.1 

RSTRNT1 -30.7 -35.4 -35.6 -4.2 

Average -17.8 -22.6 -22.9 -1.1 

14.4 Results by Climate Zone 

Table 14-7 shows the nationwide average change in energy use by ASHRAE climate zone 

for the adoption of the LEC design relative to current state energy codes for all building 

types. Average reduction in energy use nationwide is 17.8 %. Zone 1 realizes the greatest 

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average reduction in energy use, 22.1 %, while Zone 8 realizes the smallest, 10.2 %. For 

Zone 1 through Zone 5, the warmer the climate the greater the reduction in energy use, 

which is a result of the energy efficiency improvement options considered in the LEC 

design. Warmer climates have an additional option (adding overhangs) that is not 

beneficial in the colder climates because solar heat gains are beneficial in cold climates 

and harmful in warm climates. 

Zone 7 realizes a greater overall average reduction in energy use (19.8 %) than Zone 6 

(16.1 %), Zone 5 (14.9 %), or Zone 4 (18.6 %). To explain this result, the average 

percentage change in energy use by climate zone is segmented by a location’s current 

energy code in Table 14-7. Considering only the states that have adopted ASHRAE 

90.1-2007, the average percentage reduction in energy use consistently decreases from 

Zone 4 (-15.7 %) to Zone 7 (-11.1 %) where the warmer the climate zone, the greater the 

reduction in energy use. 

Table 14-7 Average Percentage Change in Energy Use for LEC by Climate Zone 

and State Energy Code 

Percentage Change by State Energy Code Climate
 

Zone/Subzone 1999 2001 2004 2007 All
 

1 -23.1 -21.2 -22.1 

2 -38.3 -26.4 -18.2 -20.7 

A -37.4 -18.3 -19.3 

B -39.2 -26.4 -17.6 -27.4 

3 -32.8 -27.4 -19.1 -18.6 -21.3 

A -32.8 -27.4 -18.5 -17.3 -22.6 

B -21.3 -19.7 -19.8 

C -17.5 -17.5 

4 -27.4 -26.4 -19.0 -15.7 -18.6 

A -26.7 -26.4 -19.0 -15.8 -19.5 

B -31.0 -16.9 -19.7 

C -14.9 -14.9 

5 -27.8 -25.1 -17.1 -13.3 -14.9 

A -25.2 -22.8 -13.1 -13.5 

B -30.4 -25.9 -17.1 -14.3 -17.8 

6 -23.0 -22.0 -16.1 -12.9 -16.1 

A -21.9 -20.8 -16.1 -12.5 -15.1 

B -23.8 -22.7 -13.3 -17.5 

7 -22.7 -20.1 -11.1 -19.8 

8 -10.2 -10.2 

Grand Total -25.5 -25.2 -19.1 -15.3 -17.8 

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Table 14-8 shows that the overall average reduction in energy costs over a 10-year study 

period ranges from 21.0 % to 25.5 % depending on the climate zone. The greatest overall 

reductions in in energy costs are realized by cities located in Zone 7 followed by Zone 3. 

Similar to energy use, this result can largely be explained by segmenting the average 

percentage change in energy costs for a climate zone by a location’s current energy code. 

Considering only the states that have adopted ASHRAE 90.1-2007, the average 

percentage reductions in energy costs trend lower from the warmer to colder climate 

zones. However, there is some additional variation that results from each location’s 

average cost per unit of energy. For example, cities in Zone 3 realize the greatest 

reductions in energy costs, particularly the cities in California located in Subzone 3C 

because the state average cost of electricity in California is the 9th highest in the United 

States. 

Table 14-8 Average Percentage Change in Energy Costs for LEC by Climate Zone 

and State Energy Code, 10-Year 

Percentage Change by State Energy Code Climate 

Zone/Subzone 1999 2001 2004 2007 All 

1 -23.1 -21.3 -22.2 

2 -39.5 -26.4 -20.4 -22.6 

A -39.1 -20.4 -21.4 

B -39.9 -26.4 -20.0 -28.2 

3 -36.8 -33.7 -22.9 -22.2 -25.3 

A -36.8 -33.7 -22.3 -20.2 -26.4 

B -25.0 -23.4 -23.5 

C -25.0 -25.0 

4 -33.5 -30.2 -21.9 -20.2 -23.2 

A -32.9 -30.2 -21.9 -20.3 -24.0 

B -37.2 -23.3 -26.1 

C -18.8 -18.8 

5 -34.9 -33.4 -21.8 -19.4 -21.0 

A -33.3 -26.5 -19.5 -20.0 

B -36.4 -35.7 -21.8 -18.8 -23.3 

6 -30.8 -31.6 -17.7 -16.7 -21.2 

A -29.7 -28.5 -17.7 -16.7 -19.8 

B -31.7 -33.2 -16.7 -23.0 

7 -30.4 -19.7 -16.8 -25.5 

8 -23.4 -23.4 

Grand Total -32.4 -32.3 -21.8 -19.7 -22.6 

Average energy-related carbon emissions are assumed constant across study period 

lengths. The data reported in Table 14-9 show that the average reduction in energy121
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Savings from Nationwide Adoption of Low Energy Case 

related carbon emissions for the LEC design ranges from 18.5 % to 25.8 % depending on 

climate zone. Even though carbon emissions are a function of electricity and natural gas 

consumption, greater reductions in energy use do not necessarily lead to greater reduction 

in carbon emissions. The greatest reductions in carbon emissions occur in Zone 3 

(25.8 %) followed by Zone 7 (25.1 %). The lowest reduction occurs in Zone 8 (18.5 %) 

followed by Zone 6 (21.3 %) and Zone 5 (21.4 %). 

Similar to energy use and energy costs, this result can largely be explained by segmenting 

the average percentage change in energy-related carbon emissions for a climate zone by a 

location’s current energy code. Considering only the states that have adopted ASHRAE 

90.1-2007, the average percentage reductions in carbon emissions trend lower from the 

warmer to colder climate zones. However, there is some additional variation that results 

from two factors. First, cities that realize a greater shift in energy use from electricity to 

natural gas realize greater reductions in carbon emissions. Second, cities with a greater 

differential in average emissions per unit of electricity relative to natural gas will realize 

greater reductions per unit of energy shifted from natural gas to electricity. 

Table 14-9 Average Change in Energy-related Carbon Emissions for LEC by 

Climate Zone and State Energy Code 

Percentage Change by State Energy Code Climate
 

Zone/Subzone 1999 2001 2004 2007 All
 

1 -23.9 -22.0 -23.0 

2 -40.1 -27.3 -21.0 -23.2 

A -39.9 -21.0 -22.0 

B -40.3 -27.3 -20.3 -28.8 

3 -38.8 -36.2 -23.6 -22.2 -25.8 

A -38.8 -36.2 -23.3 -21.3 -27.9 

B -24.5 -22.9 -23.0 

C -21.8 -21.8 

4 -36.3 -34.8 -23.0 -20.7 -24.3 

A -35.9 -34.8 -23.0 -21.0 -25.6 

B -38.7 -22.4 -25.7 

C -19.3 -19.3 

5 -37.0 -36.1 -21.5 -19.6 -21.4 

A -36.2 -33.9 -19.8 -20.5 

B -37.9 -36.8 -21.5 -18.9 -23.4 

6 -31.0 -32.8 -18.4 -16.7 -21.3 

A -30.4 -29.6 -18.4 -16.9 -20.1 

B -31.5 -34.5 -16.4 -23.0 

7 -29.3 -20.1 -17.8 -25.1 

8 -18.5 -18.5 

Grand Total -32.9 -35.1 -22.3 -20.0 -22.9 

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The results reported in Table 14-10 show that changes in life-cycle costs vary across 

climate zones and study periods. The LEC design is cost-effective for all study periods 

across all climate zones. The percentage reduction in life-cycle costs becomes smaller 

from the 1-year to 5-year and 10-year study periods, and then slowly increases from the 

10-year to 40-year study period. For study period lengths of 10 years or greater, the 

warmer the climate zone, the greater the percentage reduction in life-cycle costs. For 

example, the average percentage reduction for the 40-year study period ranges from 

3.0 % in Zone 1 to 0.6 % for Zone 8. 

Table 14-10 Average Percentage Change in Life-Cycle Costs for LEC by Climate 

Zone and Study Period 

Climate Study Period Length 

Zone/Subzone 1 5 10 15 20 25 30 35 40 

1 -10.7 -3.3 -2.5 -2.9 -2.6 -2.7 -2.9 -3.0 -3.0 

2 -2.7 -1.4 -1.4 -2.1 -2.0 -2.1 -2.3 -2.5 -2.4 

A -1.8 -1.1 -1.2 -1.9 -1.7 -1.9 -2.1 -2.2 -2.2 

B -6.9 -2.8 -2.5 -3.4 -3.1 -3.3 -3.5 -3.6 -3.6 

3 -3.1 -1.3 -1.3 -1.6 -1.8 -2.2 -2.4 -2.5 -2.4 

A -2.9 -1.3 -1.3 -1.7 -2.0 -2.4 -2.6 -2.7 -2.6 

B -3.4 -1.5 -1.4 -1.6 -1.8 -2.1 -2.3 -2.4 -2.2 

C -2.8 -0.6 -0.6 -0.9 -0.6 -1.0 -1.4 -1.5 -1.4 

4 -2.3 -0.9 -0.9 -1.8 -1.6 -1.8 -2.1 -2.2 -2.1 

A -2.2 -0.9 -1.0 -2.0 -1.8 -2.0 -2.3 -2.5 -2.4 

B -2.7 -1.2 -1.2 -2.0 -1.8 -2.1 -2.4 -2.6 -2.4 

C -2.4 -0.4 -0.4 -1.1 -0.8 -0.9 -1.2 -1.3 -1.2 

5 -4.6 -1.2 -1.0 -1.4 -1.2 -1.3 -1.5 -1.7 -1.7 

A -3.9 -0.9 -0.9 -1.2 -1.0 -1.2 -1.4 -1.6 -1.6 

B -6.1 -1.7 -1.4 -1.8 -1.5 -1.6 -1.8 -2.0 -1.9 

6 -3.6 -0.8 -0.8 -1.0 -0.8 -0.9 -1.0 -1.2 -1.1 

A -3.8 -0.9 -0.9 -1.1 -0.9 -1.1 -1.2 -1.3 -1.2 

B -3.4 -0.7 -0.7 -0.9 -0.7 -0.8 -0.9 -1.0 -0.9 

7 -3.4 -0.8 -1.0 -1.2 -1.1 -1.2 -1.4 -1.5 -1.5 

8 -19.4 -1.7 -0.6 -0.5 -0.3 -0.4 -0.6 -0.7 -0.6 

Average -3.8 -1.1 -1.1 -1.5 -1.4 -1.6 -1.8 -1.9 -1.9 

14.5 Low Energy Case Summary 

The LEC design is the most energy efficient building design considered in this study, 

which leads to the greatest percentage savings in energy use, energy costs, and carbon 

emissions overall. There are several factors that impact the percentage savings from 

adopting the LEC design, including the current state energy code, selected study period 

length, building type, and climate zone of the location. 

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Savings from Nationwide Adoption of Low Energy Case 

On average, the nationwide adoption of the LEC design as the building energy code for a 

3-story office building significantly decreases energy use (23.0 %), energy costs 

(25.2 %), and carbon emissions (22.9 %), while reducing life-cycle costs (2.2 %) for a 

10-year study period. The LEC design is cost-effective for 43 of 50 states. All seven 

states that realize an increase in life-cycle costs have adopted no energy code or a code 

based on ASHRAE 90.1-1999/2001. 

The study period length impacts the resulting reductions in life-cycle costs. For a 5-year 

study period, four of 11 building types realize an increase in life-cycle costs, on average 

across the United States. These same four building types become cost-effective as the 

study period becomes longer, with all four becoming cost-effective for a 15-year study 

period. Setting the study period length is a determinant to some degree of the size of the 

life-cycle cost savings, in percentage terms, for the most energy efficient commercial 

buildings. 

Different building types realize different national average percentage reductions in 

energy use, energy costs, life-cycle costs, and carbon emissions. The buildings with the 

greatest window-to-wall ratios tend to realize the lowest energy use, energy costs, and 

carbon emissions reductions while restaurants and small office buildings realize the 

greatest reductions. The greatest reductions in life-cycle costs for a 10-year study period 

are realized by restaurants followed by 3- and 8-story office buildings while the only 

building type to realize an increase in life-cycle costs is the 16-story office building. 

The climate zone of a location impacts the percentage reduction in energy use, energy 

costs, carbon emissions, and life-cycle costs. After controlling for the current state energy 

code, the warmest climates realize the greatest average percentage reductions in energy 

use. The average percentage reduction in energy costs is correlated with reductions in 

energy use, but there is less variation because colder locations realize a shift in energy 

use from more expensive electricity to cheaper natural gas. So even though overall 

energy use does not decrease as much in the colder climate zones, the overall energy cost 

savings are greater per percentage reduction in energy use. The shift in energy use from 

electricity to natural gas consumption also decreases carbon emissions because natural 

gas is “cleaner” than electricity in terms of cradle-to-grave energy-related carbon 

emissions. Therefore, the reductions in carbon emissions per percentage reduction in 

energy use are greater in the colder climate zones. In general, the warmer the climate, the 

greater the percentage reduction in life-cycle costs from adopting the LEC design, 

particularly for longer study periods. 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

15 Savings from Nationwide Adoption of ASHRAE 90.1-2007 

This section analyzes benefits from nationwide adoption of ASHRAE 90.1-2007 relative 

to the current collection of state energy codes. Benefits are evaluated across several 

dimensions: geography (state and climate zone), time, and building type. 

It would be expected that states with energy codes based on older editions of ASHRAE 

90.1, or no energy code at all, would realize greater benefits from adopting ASHRAE 

90.1-2007 because buildings in those states are expected to be built in a less energy 

efficient manner. Figure 15-1 shows the 14 states with energy codes based on older 

editions of ASHRAE 90.1 (-1999, -2001, or no energy code).32 Most of the central U.S. 

states have adopted older energy standard editions, as have a few states in the south, West 

Virginia, Maine, Arizona, and Alaska. 

Figure 15-1 States that have Adopted ASHRAE 90.1-2001 or No Energy Code 

The 32 states that have adopted ASHRAE 90.1-2007, highlighted gray in Figure 15-2, are 

spread out across the nation from the West Coast across to the Northeast and down to 

Florida. These states will be white in the figures in this section, and are excluded from the 

analysis because there are no impacts to report. 

32 All maps are generated in ArcMap 10.1. 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

Figure 15-2 States that have Adopted ASHRAE 90.1-2007 

As in the state-by-state analysis of the LEC design, analyzing benefits from adopting the 

ASHRAE 90.1-2007 design requires an assumption on the study period length because 

costs to maintain and operate a building fluctuate over time. A 10-year study period is 

used as the baseline because it is one of the most realistic investor time frames of the 9 

study period length options in BIRDS. The significance of the study period length will be 

tested in Section 15.2. 

15.1 State Comparisons 

State benefit comparisons are made based on the simple average changes for the cities 

analyzed in each state by building type.33 One building type is chosen to illustrate the 

detailed analysis possible with the powerful BIRDS database compiled for this study. 

Energy use, energy costs, life-cycle costs, and carbon emissions are analyzed for the most 

common existing building type, small office buildings. Summary results for the other 10 

building types are reported in Table B-11 through Table B-20 in Appendix B. 

15.1.1 3-Story Office Building 

Table 15-1 summarizes the percentage changes in energy use, energy costs, life-cycle 

costs, and carbon emissions for the 3-story office building for a 10-year study period. On 

average, adoption of ASHRAE 90.1-2007 for a 3-story office building decreases energy 

use, energy costs, and energy-related carbon emissions by over 10 % each while 

increasing life-cycle costs (0.5 %). These results exclude the states that have already 

adopted ASHRAE 90.1-2007. 

33 City-level data are not available to weight by amount of building construction in each city. 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

Table 15-1 Average Percentage Change by State, 3-Story Office Building, 10-Year
 

Percentage Change Percentage Change 

State State Energy Energy Carbon LCC Energy Energy Carbon LCC 

Use Cost Use Cost 

AK -8.0 -10.6 -9.7 0.9 MS -26.4 -21.1 -20.9 1.7 

AL -19.0 -18.3 -17.9 1.2 ND -12.5 -12.9 -13.0 2.4 

AR -12.2 -13.8 -14.3 -3.4 NV -5.7 -2.7 -3.5 -0.4 

AZ -15.8 -14.1 -13.7 0.6 OK -13.8 -15.6 -16.8 2.6 

CO -11.3 -10.9 -10.9 -2.6 SC -2.6 -2.4 -2.4 -0.6 

HI -1.6 -1.6 -1.6 -0.3 SD -12.6 -12.8 -12.8 0.8 

KS -15.0 -14.4 -14.3 3.3 TN -4.6 -2.6 -2.3 -0.4 

ME -14.2 -13.8 -13.8 1.6 WV -13.5 -13.1 -12.1 -2.1 

MN -9.2 -4.3 -3.8 -0.5 WY -13.3 -13.6 -13.6 2.2 

MO -14.8 -14.2 -13.9 3.0 Avg. -11.4 -10.6 -10.5 0.5 

These detailed results can be readily analyzed in mappings of the United States. Figure 

15-3, Figure 15-4, Figure 15-6, and Figure 15-5 overlay Figure 15-1 and display the 

average percentage energy savings, energy cost savings, life-cycle cost savings, and 

carbon emissions reduction by state, respectively. The states with codes based on older 

editions of ASHRAE 90.1, or no energy code at all, are shown with cross hatching and 

bolded state borders. The 31 states that have already adopted ASHRAE 90.1-2007 are 

shown in white and are excluded from the analysis. Figure 15-3 shows that 16 of 19 

states realize energy use savings greater than 5 % by adopting ASHRAE 90.1-2007 over 

their current state energy code. Many of the states that realize the greatest energy use 

savings are the ones that currently have no energy code or energy codes based on older 

editions of ASHRAE 90.1 including all 13 states that realize energy use savings of more 

than 10 %. 

Figure 15-3 Average Energy Use Savings by State, 3-Story Office Building, 10-Year 

Figure 15-4 overlays Figure 15-1 with the average energy cost savings over 10 years by 

state from adopting ASHRAE 90.1-2007 in small office buildings. Every state reduces 

energy costs. The 14 states that currently have no energy code or energy codes based on 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

older editions of ASHRAE 90.1 are the top 14 in energy cost savings, with all 14 states 

realizing savings of greater than 10 %. 

Figure 15-4 Average Energy Cost Savings by State, 3-Story Office Building, 

10-Year 

Figure 15-5 overlays Figure 15-1 with the average energy-related reduction in carbon 

emissions by state from adopting ASHRAE 90.1-2007. All states reduce carbon 

emissions. The states that currently have no energy code or energy codes based on older 

editions of ASHRAE 90.1 realize the greatest reduction in carbon emissions, with all 14 

states realizing savings of greater than 5 % and 13 states realizing reductions of over 10 

%. All 5 states that have adopted ASHRAE 90.1-2004 as its state energy code realize 

reductions in carbon emissions of less than 5 %. 

Figure 15-5 Average Carbon Reduction by State, 3-Story Office Building, 10-Year 

For a 3-story office building, as expected, states that currently have no energy code or 

energy codes based on older editions of ASHRAE 90.1 have the most to gain in 

percentage terms in energy use, energy cost, and carbon emissions savings from adopting 

more stringent state energy codes. However, the life-cycle cost-effectiveness of such 

adoptions varies across states. 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

Figure 15-6 overlays Figure 15-1 with the average life-cycle cost savings over 10 years 

by state from adopting ASHRAE 90.1-2007. Of the 19 states, 8 realize a decrease in lifecycle costs, on average. All 5 of the states that have adopted ASHRAE 90.1-2004 as its 

state energy code realize reductions in life-cycle costs. There is significant variation in 

the average percentage change for the states that currently have no energy code or energy 

codes based on older editions of ASHRAE 90.1. 

Figure 15-6 Average Life-Cycle Cost Savings by State, 3-Story Office Building, 

10-Year 

15.2 Results by Study Period Length 

The nationwide analysis up to this point has focused on 3-story office buildings over a 

10-year study period. It is important to consider how the study period length – 

representing the time horizon of the investor -- impacts energy use, energy costs, energyrelated carbon emissions, and life-cycle costs. Nine study periods are analyzed: 1 year, 5 

years, 10 years, 15 years, 20 years, 25 years, 30 years, 35 years, and 40 years. All 

building types are included in this analysis. 

Average reduction in energy use from adoption of ASHRAE 90.1-2007 is constant over 

all study period lengths because energy efficiency is assumed to be constant over time. 

The national average change in energy use across all cities in the study ranges 

from -15.6 % to 0.5 %, depending on the building type, with an overall national average 

of -9.6 %. The 16-story office building realizes a percentage increase in energy use 

because the relaxation of the window requirements overwhelms the impacts from the 

other energy efficiency measures required by ASHRAE 90.1-2007. Table 15-2 shows 

these results. 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

Table 15-2 Nationwide Average Percentage Change in Energy Use by Building
 

Type 

Building 

Type 

Percentage 

Change 

APART04 

APART06 

DORMI04 

DORMI06 

HOTEL15 

HIGHS02 

OFFIC03 

OFFIC08 

OFFIC16 

RETAIL1 

RSTRNT1 

Average 

-11.4 

-11.0 

-12.3 

-10.7 

-3.2 

-5.8 

-11.4 

-9.8 

0.5 

-15.2 

-15.6 

-9.6 

As shown in Table 15-3, savings in energy costs varies slightly, in percentage terms, over 

increasing study period lengths. The national average change in energy costs across all 

location-building type combinations ranges from -12.3 % to -12.0 % for all study period 

lengths. There is minor variation of up to 0.6 percentage points for some building types 

across study periods as a result of the escalation rates used to adjust future energy prices, 

which vary by U.S. Census Region. 

Table 15-3 Nationwide Average Percentage Change in Energy Costs by Building 

Type and Study Period Length 

Building Study Period Length 

Type 1 5 10 15 20 25 30 35 40 

APART04 -16.9 -16.7 -16.7 -16.6 -16.5 -16.4 -16.3 -16.3 -16.3 

APART06 -16.6 -16.4 -16.3 -16.2 -16.2 -16.1 -16.0 -16.0 -16.0 

DORMI04 -17.4 -17.3 -17.2 -17.1 -17.1 -17.0 -16.9 -16.9 -16.9 

DORMI06 -16.5 -16.4 -16.3 -16.2 -16.1 -16.0 -16.0 -16.0 -16.0 

HOTEL15 -8.3 -8.2 -8.1 -8.0 -8.0 -7.9 -7.8 -7.8 -7.8 

HIGHS02 -7.8 -7.7 -7.7 -7.7 -7.6 -7.6 -7.6 -7.6 -7.6 

OFFIC03 -10.6 -10.6 -10.6 -10.6 -10.6 -10.7 -10.7 -10.7 -10.7 

OFFIC08 -9.5 -9.5 -9.5 -9.5 -9.5 -9.5 -9.5 -9.5 -9.5 

OFFIC16 -0.9 -0.8 -0.8 -0.8 -0.8 -0.8 -0.7 -0.7 -0.7 

RETAIL1 -15.1 -15.1 -15.1 -15.1 -15.1 -15.1 -15.1 -15.1 -15.1 

RSTRNT1 -15.5 -15.5 -15.5 -15.5 -15.5 -15.5 -15.5 -15.5 -15.5 

Average -12.3 -12.2 -12.2 -12.1 -12.1 -12.1 -12.0 -12.0 -12.0 

Since the national average reduction in energy use across all location-building type 

combinations is constant over all study period lengths, the average change in energyrelated carbon emissions is also constant at -4.0 %. The national average change in 

carbon emissions ranges from -5.7 % to -0.3 % depending on the building type, as shown 

in Table 15-4. 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

Table 15-4 Nationwide Average Percentage Change in Carbon Emissions by 

Building Type 

Building Percentage 

Type Change 

APART04 -17.4 

APART06 -17.1 

DORMI04 -17.9 

DORMI06 -17.1 

HOTEL15 -11.5 

HIGHS02 -8.8 

OFFIC03 -8.2 

OFFIC08 -10.5 

OFFIC16 -9.3 

RETAIL1 -0.9 

RSTRNT1 -15.0 

Average -15.6 

Table 15-5 shows that the percentage change in life-cycle costs varies slightly over 

increasing study period lengths, with the average change across all location-building type 

combinations ranging from -1.9 % for a 1-year study period to -0.7 % for a 10-year study 

period. The national average change in life-cycle costs ranges from -6.7 % to 2.3 % 

depending on the building type for a 1-year study period. The nationwide change in lifecycle costs averages -0.7 % for a 10-year study period length, ranging from -1.7 % to 

0.5 % depending on the building type. As the study period length increases from 10 years 

to 40 years, the percentage reduction in national average life-cycle costs increases, with 

an overall average percentage change of -0.7 % to -1.1 %, respectively. Also, the number 

of building types that realize reductions in life-cycle costs increases from 7 for a 20-year 

study period to 10 for a 40-year study period. 

Table 15-5 National Average Percentage Change in Life-Cycle Costs by Building 

Type and Study Period Length 

Building Study Period Length 

Type 1 5 10 15 20 25 30 35 40 

APART04 -1.8 -1.8 -1.7 -1.8 -1.9 -1.9 -1.9 -2.0 -2.0 

APART06 -1.1 -1.6 -1.6 -1.8 -1.8 -1.9 -1.9 -2.0 -2.0 

DORMI04 -4.1 -1.1 -0.9 -1.0 -1.1 -1.2 -1.2 -1.3 -1.4 

DORMI06 -2.1 -2.1 -2.0 -2.1 -2.1 -2.2 -2.2 -2.3 -2.3 

HOTEL15 -1.4 -1.3 -1.2 -1.2 -1.2 -1.2 -1.2 -1.2 -1.2 

HIGHS02 -1.4 -0.8 -0.8 -0.9 -0.9 -1.0 -1.1 -1.1 -1.1 

OFFIC03 -3.1 0.4 0.5 0.3 0.2 0.1 0.1 0.0 -0.1 

OFFIC08 0.2 0.6 0.5 0.3 0.1 -0.0 -0.0 -0.1 -0.2 

OFFIC16 -1.5 -0.3 -0.1 0.1 0.1 0.2 0.2 0.2 0.3 

RETAIL1 -6.7 -1.2 -0.9 -1.1 -1.2 -1.3 -1.4 -1.4 -1.5 

RSTRNT1 2.3 0.8 0.4 0.0 -0.2 -0.4 -0.5 -0.6 -0.7 

Average -1.9 -0.8 -0.7 -0.8 -0.9 -1.0 -1.0 -1.1 -1.1 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

15.3 Results by Building Type 

Table 15-6 shows the simple average changes, in percentage terms, from adopting 

ASHRAE 90.1-2007 by building type for a 10-year study period length. The tallest 

buildings realize the lowest reductions in energy use. The only building type that realizes 

an increase in energy use is the 16-story office building. The hotel and high school realize 

reductions in energy use of 3.2 % and 5.8 %, respectively. The remaining building types 

all realize reductions in energy use greater than 9.8 %. All building types realize 

reductions in energy costs, ranging from 0.8 % to 17.2 %. The 16-story office building 

realizes small reductions in energy costs even though its energy use increases because 

energy use is shifted from electricity to natural gas. The apartments and dormitories 

realize the greatest reductions in energy costs. All building types realize reductions in 

energy-related carbon emissions, ranging from 0.9 % to 17.9 %. The greatest reductions 

in carbon emissions are realized by the apartment buildings and dormitories at over 

15.0 % while the smallest reductions are realized by the 16-story office building. Of the 

11 building types, 8 realize a decrease in life-cycle costs. The greatest reductions in 

life-cycle costs are realized by the 6-story dormitory (2.0 %) and 4-story apartment 

building (1.7 %). The greatest life-cycle cost increases are realized by the 3-and 8-story 

office buildings (0.5 % each) and the restaurant (0.4 %). 

Table 15-6 Nationwide Percentage Change for ASHRAE 90.1-2007 by Building 

Type, 10-Year 

Building Percentage Change 

Type Energy Use Energy Cost LCC Carbon 

APART04 -11.4 -16.7 -1.7 -17.4 

APART06 -11.0 -16.3 -1.6 -17.1 

DORMI04 -12.3 -17.2 -0.9 -17.9 

DORMI06 -10.7 -16.3 -2.0 -17.1 

HOTEL15 -3.2 -8.1 -1.2 -11.5 

HIGHS02 -5.8 -7.7 -0.8 -8.8 

OFFIC03 -11.4 -10.6 0.5 -8.2 

OFFIC08 -9.8 -9.5 0.5 -10.5 

OFFIC16 0.5 -0.8 -0.1 -9.3 

RETAIL1 -15.2 -15.1 -0.9 -0.9
 

RSTRNT1 -15.6 -15.5 0.4 -15.0
 

Average -9.6 -12.2 -0.7 -15.6 

Overall, the buildings with the greatest window-to-wall ratios realize the lowest 

reductions, or even increases, in energy use, energy costs, and carbon emissions while the 

residential buildings (apartments and dormitories), retail stores, and restaurants realize 

the greatest reductions. 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

15.4 Results by Climate Zone 

Table 15-7 shows the nationwide average change in energy use by ASHRAE climate 

zone. These changes are for the adoption of ASHRAE 90.1-2007 relative to current state 

energy codes for all building types. The warmest and coldest climate zones, Zone 1 and 

Zone 8, realize the smallest overall percentage changes in energy use. Zone 8 realizes an 

increase of energy use of 1.7 % while Zone 1 realizes a small decrease of 1.1 %. Zone 2 

realizes the highest reductions in energy use at 16.3 % followed by Zone 3 (12.0 %) and 

Zone 4 (10.4 %). 

Table 15-7 Average Percentage Change in Energy Use for ASHRAE 90.1-2007 by 

Climate Zone 

Climate Percentage Change 

Zone/Subzone 1999 2001 2004 All 

1 -1.1 -1.1 

2 -24.0 -8.6 -16.3 

A -23.9 -23.9 

B -24.2 -8.6 -13.8 

3 -19.6 -13.8 -1.9 -12.0 

A -19.6 -13.8 -1.7 -12.7 

B -2.7 -2.7 

4 -14.0 -12.9 -2.5 -10.4 

A -13.6 -12.9 -2.5 -10.0 

B -16.1 -16.1 

5 -14.5 -12.3 -3.5 -7.9 

A -12.7 -11.2 -11.9 

B -16.2 -12.7 -3.5 -7.2 

6 -11.2 -10.3 -4.4 -9.7 

A -10.6 -9.6 -4.4 -8.2 

B -11.7 -10.7 -11.4 

7 -10.5 -7.4 -9.7 

8 1.7 1.7 

Grand Total -12.9 -12.3 -3.7 -9.6 

Similar to the LEC design, the current state energy codes are a key driver of these results. 

The variation across climate zones diverges depending on the state energy code. For 

locations in states that have not adopted any state energy code or have adopted older 

editions of ASHRAE 90.1 (-1999 or -2001), warmer climate zones realize greater 

percentage reductions in energy use. For states that have no state energy code or have 

adopted ASHRAE 90.1-1999, cities in Zone 2 realize an average percentage reduction of 

24.0 % while Zone 8 realizes an increase of 1.7 % from adopting the ASHRAE 90.1-2007 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

design. For cities located in states that have adopted ASHRAE 90.1-2004, the percentage 

reductions in energy use are much smaller, ranging from 1.1 % to 8.6 %, and do not 

follow the same trend where colder climate zones realize smaller reductions in energy 

use. Instead the percentage changes are the greatest for cities in Zone 2 followed by Zone 

7 and smallest for cities in Zone 1 and Zone 3. 

Table 15-8 shows that the average reduction in energy costs over a 10-year study period 

ranges from 1.1 % to 15.2 % depending on the climate zone. Zone 2, Zone 3, Zone 6, and 

Zone 7 realize reductions in energy costs over 13 %. Zone 1 realizes reductions in energy 

costs of only 1.1 %. The reductions in energy costs for Zone 8 of 10.2 % could be 

considered surprising given that Zone 8 realizes an increase in energy use. 

Table 15-8 Average Percentage Change in Energy Costs for ASHRAE 90.1-2007 by 

Climate Zone, 10-Year 

Climate Percentage Change 

Zone/Subzone 1999 2001 2004 All 

1 -1.1 -1.1 

2 -24.1 -6.4 -15.2 

A -24.1 -24.1 

B -24.1 -6.4 -12.3 

3 -21.5 -18.1 -2.9 -14.1 

A -21.5 -18.1 -2.7 -14.9 

B -3.7 -3.7 

4 -17.1 -14.7 -0.9 -11.9 

A -16.7 -14.7 -0.9 -11.4 

B -19.1 -19.1 

5 -18.0 -16.4 -1.4 -8.6 

A -17.0 -13.0 -15.0 

B -19.0 -17.6 -1.4 -7.4 

6 -16.6 -17.1 -1.9 -13.8 

A -15.9 -14.7 -1.9 -10.5 

B -17.1 -18.4 -17.5 

7 -16.5 -4.2 -13.4 

8 -9.8 -9.8 

Grand Total -17.4 -16.6 -2.3 -12.1 

These results are similar to those realized for reductions in energy use in that they can be 

better explained after controlling for the current state energy codes. Reductions in energy 

use can explain some, but not all of the variation in energy costs. The remainder is a 

result of a shift in energy use from one energy source to another. For example, the 

adoption of ASHRAE 90.1-2007 leads to a percentage change in energy use of -24.0 % 

and 1.7 % for cities in Zone 2 and Zone 8, respectively. Meanwhile, the percentage 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

change in energy costs is -24.1 % and -9.8 %, respectively. The percentage change in 

energy use explains the entire percentage change in energy costs for cities in Zone 2. 

However, cities in Zone 8 realize a percentage increase in energy use and a seemingly 

contradictory decrease in energy costs. The adoption of ASHRAE 90.1-2007 decreases 

electricity consumption, but increases natural gas consumption by a greater amount. Due 

to the higher cost of electricity for cities in Zone 8, energy use is increased while energy 

costs are decreased. Similar shifts occur for cities throughout the other climate zones, 

where the size of the impact depends on the size of the fuel shift and the differential 

between the average cost of electricity and average cost of natural gas. 

Average energy-related carbon emissions are constant across study period lengths. The 

data reported in Table 15-9 show that the average reduction in energy-related carbon 

emissions for the LEC design ranges from 1.2 % to 15.3 % depending on the climate 

zone. Zone 1, Zone 8, and Zone 5 realize the smallest percentage reductions in carbon 

emissions while Zone 2 and Zone 3 realize the greatest reduction. Similar to reductions in 

energy costs, reductions in energy use can explain some, but not all of the variation in the 

reductions in carbon emissions. The remainder is a result of a shift in energy use from 

one energy source to another. For example, the adoption of ASHRAE 90.1-2007 leads to a 

percentage change in energy use of 1.7 % and a percentage change in carbon emissions 

of -5.8 % for cities in Zone 8. For Alaska, the average carbon emissions rate for 

electricity is greater than the average carbon emissions rate for natural gas. The shift in 

energy use from electricity to natural gas leads to an overall decrease in carbon emissions 

while total energy use increases. 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

Table 15-9 Average Change in Energy-related Carbon Emissions for ASHRAE 

90.1-2007 by Climate Zone 

Climate Percentage Change 

Zone/Subzone 1999 2001 2004 All 

1 -1.2 -1.2 

2 -24.0 -6.5 -15.3 

A -23.8 -23.8 

B -24.1 -6.5 -12.4 

3 -22.5 -19.7 -3.2 -15.0 

A -22.5 -19.7 -3.0 -15.9 

B -3.7 -3.7 

4 -18.3 -16.9 -1.0 -13.1 

A -18.1 -16.9 -1.0 -12.5 

B -19.6 -19.6 

5 -18.9 -17.7 -2.1 -9.5 

A -18.3 -16.8 -17.5 

B -19.5 -18.0 -2.1 -8.0 

6 -16.6 -17.9 -1.9 -14.0 

A -16.3 -15.3 -1.9 -10.8 

B -17.0 -19.2 -17.6 

7 -15.6 -3.9 -12.7 

8 -5.8 -5.8 

Grand Total -17.4 -18.0 -2.5 -12.4 

The results reported in Table 15-10 show that changes in life-cycle costs vary across 

climate zones and study periods. Adopting ASHRAE 90.1-2007 is cost-effective for all 

study periods, on average, in Zone 2, Zone 3, Zone 5, Zone 6, Zone 7, and Zone 8. 

Adopting ASHRAE 90.1-2007 is not cost-effective in Zone 1 and Zone 4 over a 1-year 

study period, but is cost-effective at 5 years and 10 years, respectively. 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

Table 15-10 Average Percentage Change in Life-Cycle Costs for ASHRAE 

90.1-2007 by Climate Zone and Study Period 

Climate Study Period Length 

Zone/Subzone 1 5 10 15 20 25 30 35 40 

1 0.7 -0.1 -0.2 -0.3 -0.3 -0.3 -0.3 -0.3 -0.3 

2 -4.9 -1.4 -1.2 -1.4 -1.4 -1.6 -1.5 -1.6 -1.7 

A -1.1 -0.5 -0.8 -1.2 -1.4 -1.6 -1.6 -1.8 -1.9 

B -6.2 -1.7 -1.3 -1.5 -1.5 -1.5 -1.5 -1.6 -1.6 

3 -0.6 -0.9 -1.0 -1.2 -1.5 -1.6 -1.7 -1.7 -1.8 

A -0.6 -1.0 -1.1 -1.3 -1.5 -1.7 -1.7 -1.8 -1.9 

B -0.6 -0.5 -0.4 -0.5 -0.5 -0.5 -0.5 -0.5 -0.5 

4 1.0 -0.0 -0.2 -0.5 -0.5 -0.6 -0.6 -0.7 -0.7 

A 0.8 -0.1 -0.3 -0.5 -0.5 -0.6 -0.6 -0.7 -0.7 

B 2.6 0.5 0.1 -0.4 -0.5 -0.6 -0.6 -0.7 -0.8 

5 -3.2 -1.2 -0.9 -1.0 -0.9 -0.9 -0.9 -1.0 -1.0 

A -2.1 -1.1 -1.1 -1.2 -1.2 -1.3 -1.3 -1.5 -1.6 

B -3.4 -1.2 -0.9 -0.9 -0.9 -0.9 -0.9 -0.9 -0.9 

6 -2.2 -0.8 -0.8 -0.8 -0.9 -1.0 -1.0 -1.1 -1.1 

A -2.5 -0.7 -0.6 -0.6 -0.7 -0.7 -0.8 -0.8 -0.9 

B -1.8 -1.0 -1.0 -1.1 -1.1 -1.2 -1.2 -1.3 -1.4 

7 -6.1 -1.0 -0.7 -0.7 -0.7 -0.8 -0.8 -0.9 -0.9 

8 -0.7 -0.2 -0.2 -0.3 -0.4 -0.4 -0.5 -0.5 -0.6 

Average -1.9 -0.8 -0.7 -0.8 -0.9 -1.0 -1.0 -1.1 -1.1 

Figure 2-2 shows that the average change in life-cycle costs converges at the 10-year 

study period, with cities in all climate zones realizing reductions in life-cycle costs by for 

study period of 5 years or greater. In general, the cost-effectiveness of adopting ASHRAE 

90.1-2007 increases as the study period length increases from 10 years to 40 years. These 

results emphasize the importance of selecting the appropriate study period for the 

analysis. 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

Change in Life-cycle Costs (%)
 

1.0 

0.0 

-1.0 

-2.0 

-3.0 

-4.0 

-5.0 

-6.0 

1 5 10 15 20 25 30 35 40
 

Zone 1 

Zone 2 

Zone 3 

Zone 4 

Zone 5 

Zone 6 

Zone 7 

Zone 8 

Study Period
 

Figure 15-7 Percentage Change in Life-Cycle Cost from Nationwide Adoption of
 

ASHRAE 90.1-2007 by Study Period Length and ASHRAE Climate Zone
 

15.5 ASHRAE 90.1-2007 Summary 

ASHRAE 90.1-2007 is the most recent edition of ASHRAE 90.1 considered in this study, 

and is the newest edition to be adopted by a state as its commercial building energy code 

as of December 2011. 

Overall, the adoption of ASHRAE 90.1-2007 leads to reductions in energy use, energy 

costs, and carbon emissions. There are several factors that impact the percentage savings 

from adopting ASHRAE 90.1-2007, including the current state energy code, selected 

study period length, building type, and climate zone of the location. 

The nationwide adoption of ASHRAE 90.1-2007 as the commercial building energy code 

for a 3-story office building decreases energy use (11.4 %), energy costs (10.6 %), and 

carbon emissions (10.3 %) while increasing life-cycle costs (0.5 %) for a 10-year study 

period, on average. Although ASHRAE 90.1-2007 leads to reductions for all states for 

energy use, energy costs, and carbon emissions, the magnitude of the reductions varies 

across states due to each state’s adopted energy code. States with no energy code or a 

code based on ASHRAE 90.1-1999/2001 realize the greatest percentage savings in energy 

use, energy costs, and carbon emissions. 

The study period length impacts the resulting percentage change in life-cycle costs. For a 

20-year study period, 8 of the 11 building types realize an average reduction in life-cycle 

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Savings from Nationwide Adoption of ASHRAE 90.1-2007 

costs with a percentage change in life-cycle costs of -2.1 % to 0.2 %. Two additional 

building types (10 of 11) become cost-effective at a 40-year study period, with a 

percentage change in life-cycle costs of -2.3 % to -0.1 %. Selecting the appropriate study 

period length is a major determinant in the life-cycle cost-effectiveness of adopting 

ASHRAE 90.1-2007 as a state energy code for commercial buildings. 

Different building types realize different national average percentage changes in energy 

use, energy costs, life-cycle costs, and carbon emissions. Overall, the buildings with the 

greatest window-to-wall ratios realize the lowest reductions in energy use, energy costs, 

and carbon emissions while the residential buildings (apartments and dormitories), retail 

stores, and restaurants realize the greatest reductions. 

The climate zone of a location impacts the percentage reduction in energy use, energy 

costs, carbon emissions, and life-cycle costs. After controlling for each state’s energy 

code, cities in warmer climates tend to realize greater percentage reductions in energy 

use. The average percentage reduction in energy use can explain some, but not all the 

variation in the average percentage reductions in energy costs and carbon emissions. The 

remaining variation is driven by the relative cost and emissions rate per unit of energy for 

the two energy sources, where electricity is higher in both categories. There is a high 

correlation in the warmest climate zone (Zone 1) because nearly all energy use is from 

electricity consumption. For locations in which both electricity and natural gas 

consumption decreases, the energy cost and carbon emissions reductions are less than the 

reductions in energy use. For locations in which electricity consumption decreases while 

natural gas consumption increases (a.k.a. a shift from cooling loads to heating loads), the 

energy cost and carbon emissions reductions are greater than the reductions in energy 

use. In the extreme case (Zone 8), the increase in natural gas use is greater than the 

decrease in electricity use, leading to an increase in energy use while the shift to natural 

gas decreases energy costs and carbon emissions. In general, cities in warmer climate 

zones tend to realize a greater percentage reduction in life-cycle costs. 

139
 
Savings from Nationwide Adoption of ASHRAE 90.1-2007 

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Discussion 

16 Discussion 

This study analyzes the impacts of adopting new, more stringent state energy codes for 

228 cities located across the United States for 11 prototypical building types. Results are 

summarized at the national level as well as the state level for 7 representative states. This 

section will discuss the key findings, limitations of the research, and recommended 

directions for future research. 

16.1 Key Findings 

Overall, adoption of ASHRAE 90.1-2007 for the 19 states that have not yet adopted it as 

their state energy code leads to reductions in energy use, energy costs, and energy-related 

carbon emissions. The average state reduction in energy use for new commercial 

buildings is 9.6 % while energy costs and carbon emissions realize average reductions of 

12.2 % and 12.4 %, respectively for a 10-year study period. The reductions in energy use 

and carbon emissions are cost-effective, with average life-cycle costs decreasing by 

0.7 %. 

However, ASHRAE 90.1-2007 does not lead to energy efficiency improvements over 

older editions of ASHRAE 90.1 for all locations in the U.S. for two reasons. First, the 

simplification of the ASHRAE climate zones from 26 zones in ASHRAE 90.1-2001 to 8 

zones in ASHRAE 90.1-2004 resulted in the relaxation of some building envelope 

requirements for some locations. Second, ASHRAE 90.1-2007 has less stringent solar heat 

gain coefficient (SHGC) requirements relative to ASHRAE 90.1-2004 for some climate 

zones. As a result, high-rise, 100 % glazed buildings realize smaller reductions, and 

occasionally increases, in energy use because the less stringent window requirements 

overwhelm the stricter requirements for other energy efficiency measures analyzed in this 

study. 

Overall, adoption of the LEC design in all 50 states leads to nationwide reductions in 

energy use, energy costs, and carbon emissions greater than those realized by ASHRAE 

90.1-2007. The average state reduction in energy use is 17.8 % over current state energy 

codes while energy costs and carbon emissions realize average reductions of 22.6 % and 

20.4 %, respectively. The reductions in energy use and carbon emissions are costeffective, with life-cycle costs decreasing by 1.1 % on average for a 10-year study period. 

States with current energy codes based on older editions of ASHRAE 90.1 realize greater 

reductions in energy use, energy costs, and carbon emissions for the ASHRAE 90.1-2007 

design. For a small office building, the 13 states with reductions in energy use of at least 

10 % have no state energy code or have adopted ASHRAE 90.1-1999/2001. For the LEC 

design, 14 of the 18 states that realize reductions in energy use greater than 25 % have no 

state energy code or have adopted ASHRAE 90.1-1999/2001, including all 13 states with 

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Discussion 

reductions greater than 30 %. Similar trends hold for energy costs and energy-related 

carbon emissions. 

Over all building types, states located in the warmest climates realize the greatest 

reductions in energy use from adopting the “Low Energy Case” (LEC) design because 

several of the energy efficiency improvements (e.g., overhangs and daylighting controls) 

are more beneficial for warmer climates. However, states in colder climates see greater 

percentage reductions in energy costs and carbon emissions per percentage reduction in 

energy use because the energy efficiency measures tend to shift some energy use from 

electricity to natural gas consumption. Electricity is more expensive per unit of energy 

and typically has greater CO2e emissions factors per unit of energy relative to natural gas. 

Therefore the shift of energy consumption from electricity to natural gas can lead to 

greater reductions in energy costs and energy-related carbon emissions than reductions in 

total energy use. In an extreme case, cities located in Zone 8 realize a reduction in energy 

costs and carbon emissions while realizing an increase in total energy use. 

The results for the ASHRAE 90.1-2007 design have some similarities and some 

differences relative to the results for the LEC design. Similar to the LEC design, the 

current state energy codes are a key driver of variation in the results. The variation across 

climate zones diverges depending on the state energy code. For locations in states that 

have not adopted any state energy code or have adopted older editions of ASHRAE 90.1 

(-1999 or -2001), warmer climate zones realize greater percentage reductions in energy 

use. For cities located in states that have adopted ASHRAE 90.1-2004, the percentage 

reductions in energy use do not follow the same trend. Instead the percentage changes are 

the greatest for cities in Zone 2 followed by Zone 7 and smallest for cities in Zone 1 and 

Zone 3. 

Similar to the LEC design, many cities realize a shift in energy use from electricity to 

natural gas, which decreases energy costs and carbon emissions by a greater percentage 

than the percentage decrease in energy consumption. However, nearly all zones realize 

smaller percentage reductions in carbon emissions than the percentage reductions in 

energy use because adopting ASHRAE 90.1-2007 decreases consumption of both 

electricity and natural gas for most cities. 

The length of the study period impacts life-cycle cost-effectiveness to some degree. 

Assuming nationwide adoption of the LEC design, a 10-year study period realizes 

average life-cycle cost decreases of 1.1 % for all building types and locations. The 

percentage decrease in life-cycle costs is 1.4 % for a 20-year, and 1.8 % for a 30-year, 

and 1.9 % for a 40-year study period. As the study period length increases from 5 to 40 

years, the life-cycle cost-effectiveness tends to increase for more energy efficient 

commercial building designs. This result is supported by the state-level aggregated 

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Discussion 

impact estimates, with only one of the seven states in this study realizing an increase in 

total life-cycle costs from the adoption of the LEC design. 

States with the most newly constructed commercial building floor area realize the 

greatest total energy use, energy cost, and energy-related carbon emissions reductions 

from adopting ASHRAE 90.1-2007 or the LEC design even if those states do not realize 

the greatest percentage reductions. Maryland and Oregon, both of which have adopted 

ASHRAE 90.1-2007, realize reductions in energy use of 15 % for the LEC design. 

However, Maryland realizes total reductions in energy use of 622 GWh while Oregon 

realizes reductions of 261 GWh because Maryland has almost twice the amount of newly 

constructed floor area. Similarly, Florida, which ranks 1st in the country for new floor 

area, realizes greater aggregate reductions in energy costs and reductions in energyrelated carbon emissions than Maryland even though both states realize approximately 

the same percentage reductions in these two metrics. 

In general, the states that realize the greatest reductions in energy use also realize the 

greatest reductions in energy costs and energy-related carbon emissions. However, states 

with higher electricity and natural gas rates will realize greater reductions in energy costs. 

For example, Tennessee realizes greater aggregate reductions in energy use than 

Maryland (808 GWh versus 622 GWh), but less total energy cost savings ($58.7 million 

versus $62.4 million). Also, states that rely heavily on coal-fired electricity will realize 

greater emissions reductions per unit of energy reduced than those states using more 

alternative energy sources. For example, Colorado relies on coal for 72 % of electricity 

generation and decreases carbon emissions by over 1000 tons per GWh of electricity 

generation. Meanwhile, Oregon relies on coal for 7 % of electricity generation and only 

saves 559 tons per GWh. 

For a 10-year study period, adopting the ASHRAE 90.1-2007 design reduces total lifecycle costs for the three states in this study that have adopted an older edition of ASHRAE 

90.1 or have not yet adopted a state energy code for commercial buildings: $1.4 million 

for Alaska, $53.9 million for Colorado, and $7.5 million for Tennessee. Meanwhile, 

adopting the LEC design would decrease life-cycle costs for six of the seven states 

selected for this study, ranging from $2.4 million to $151.3 million. The variation is 

primarily driven by the amount of new construction in a state. The life-cycle cost savings 

realized by these six states makes the increase in life-cycle costs realized by Oregon 

insignificant. 

16.2 Limitations and Future Research 

The analysis in this study is limited in scope and would be strengthened by analyzing 

more states, including sensitivity analysis, expanding the BIRDS database and metrics, 

and enabling public access to all the results. 

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Discussion 

The statewide average percentage changes estimated for this study for across state 

comparisons should not be used to determine the total benefits and costs of adopting a 

more stringent state energy code. In order to translate these results into total energy use, 

energy cost, life-cycle cost, and carbon emissions estimates, it is necessary to control for 

the floor area constructed in each state. This study only analyzes 7 of the 50 states in 

detail, and cannot be extrapolated to estimate the magnitude of nationwide savings. In 

addition, extensive analysis by Census Region may show some additional variation in 

results revealing insights not captured in this study. 

Sensitivity analysis is needed for at least two assumptions in the analysis. First, consider 

the assumed discount rate. Although 3 % is a reasonable discount rate, in real terms, for 

federal government investment decisions, it may be too low of a value for an expected 

real return on an alternative investment in the private sector. Sensitivity analysis on the 

assumed discount rate is needed to determine the robustness of the cost results. Second, 

the current analysis assumes that the cooling load is met by equipment running on 

electricity while heating loads are met with equipment running on natural gas, which is 

not the typical fuel mix for some areas of the nation. The database should be expanded to 

include alternative fuel source options, such as heating oil use in the New England area. 

Additional data are needed to refine and expand the BIRDS database. First, the study uses 

simple averages to summarize energy use, energy cost, life-cycle cost, and carbon 

emissions changes across all locations in a state. However, the amount of total floor area 

constructed will vary significantly from city to city. Future research could develop a 

weighted average of savings in a state based on the fraction of newly constructed floor 

area by city. Second, the 11 prototypical buildings analyzed in this study are likely not 

representative of the entire building stock for each building type. For example, all highrise buildings are not 100 % glazed. For this reason, the results should be considered as 

general magnitudes instead of hard numbers. Future research should include additional 

prototypes, such as the DOE Benchmark Buildings, in the database. Additionally, since 

existing buildings account for nearly the entire building stock, prototypes for retrofitting 

buildings should be incorporated into the BIRDS database as well. The state average 

energy cost rates and energy-related carbon emissions rates do not control for local 

variation in energy tariffs or electricity fuel mixes. By using utility-level energy cost and 

emissions rate data, the accuracy of the estimates in BIRDS could be improved. 

The analysis in this study ignores the impacts that plug and process loads have on the 

reductions in energy use. Buildings with greater plug and process loads will realize 

smaller percentage changes in energy use because the energy efficiency measures 

considered in this study focus on the building envelope and HVAC equipment, holding 

constant the energy use from other equipment used in the building. As building energy 

efficiency improves, the plug and process loads become a larger fraction of the overall 

energy load. Future research should consider the impact the assumed plug and process 

144
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Discussion 

loads have on the overall energy savings realized by energy efficiency improvements to 

buildings. 

This study only compares the current state energy code to newer, more stringent standard 

editions. The BIRDS database is much more expansive, allowing researchers to compare 

any of the editions of ASHRAE 90.1 with any other edition of ASHRAE 90.1 or the LEC 

design. The BIRDS database should be made available to the public through a simple-touse software tool that allows other researchers to use the database for their own research 

on building energy efficiency. 

Finally, a more comprehensive sustainability assessment of the benefits and costs of 

building energy efficiency would strengthen the impact of this work. This study applies 

environmental life cycle assessment methods to evaluate the global warming potentials 

attributable to building energy efficiency improvements. In a parallel effort, the BIRDS 

database is being expanded to include a full range of 11 life-cycle environmental impacts 

covering human health effects, ecological health effects, and resource depletion. The 

sustainability assessment is also being expanded beyond building energy efficiency to 

cover the materials used in construction, MRR, and waste management. The BIRDS 

software tool in development will provide the results of this more comprehensive 

sustainability assessment alongside the results summarized in this report. 

145
 
Discussion 

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References 

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Sustainability (BEES) Online software, February 2011, NIST, 

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Building Type, New Construction, and Emissions Rates 

A Building Type, New Construction, and Emissions Rates 

Table A-1 CBECS Categories and Subcategories 

Category Subcategory 

Education elementary or middle school 

high school 

college or university 

preschool or daycare 

adult education 

career or vocational training 

religious education 

Food Sales grocery store or food market 

gas station with a convenience 

store; 

convenience store 

Food Service fast food 

restaurant or cafeteria 

Health Care hospital 

Inpatient 

inpatient rehabilitation 

Health Care 

Outpatient 

Lodging 

medical office (see previous 

column) 

clinic or other outpatient health 

care 

outpatient rehabilitation 

veterinarian 

motel or inn 

hotel 

dormitory, fraternity, or sorority 

retirement home 

nursing home, assisted living, etc. 

convent or monastery 

shelter, orphanage, halfway house 

Category Subcategory 

Public 

Assembly 

Public Order 

and Safety 

Religious None 

Worship 

social or meeting 

recreation 

entertainment or culture 

library 

funeral home 

student activities center 

armory 

exhibition hall 

broadcasting studio 

transportation terminal 

police station 

fire station 

jail, reformatory, or penitentiary 

courthouse or probation office 

Service vehicle service or vehicle repair shop 

vehicle storage/ maintenance (car 

barn) 

repair shop 

dry cleaner or laundromat 

post office or postal center 

car wash 

gas station 

photo processing shop 

beauty parlor or barber shop 

tanning salon 

copy center or printing shop 

kennel 

151
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Building Type, New Construction, and Emissions Rates 

Mercantile NonMall retail store 

beer, wine, or liquor store 

Warehouse 

and Storage 

refrigerated warehouse 

non-refrigerated warehouse 

rental center distribution or shipping center 

Mercantile Malls 

Office 

dealership or showroom for 

vehicles or boats 

studio/gallery 

enclosed mall 

strip shopping center 

administrative or professional 

office 

government office 

mixed-use office 

bank or other financial institution 

Other 

Vacant 

airplane hangar 

crematorium 

laboratory 

telephone switching 

agricultural with some retail space 

manufacturing or industrial with 

some retail space 

data center or server farm 

None 

medical office (see previous 

column) 

sales office 

contractor's office 

non-profit or social services 

research and development 

city hall or city center 

religious office 

call center 

152
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Building Type, New Construction, and Emissions Rates 

Table A-2 New Commercial Building Construction Floor Area for 2003 through 

2007 by State and Building Type (S-I) 

State Building Construction Floor Area (1,000 m2) 

Apartment 19 Healthcare 130 Hotel Office Public Assembly 111 Restaurant 13 Retail School Warehouse 126 No Prototype 259 Total AK 126 226 208 231 1448 

AL 801 705 853 1504 639 169 2485 1534 842 1740 11 272 

AR 118 465 483 647 335 77 1359 1295 335 815 5928 

AZ 1043 1505 1047 4030 1180 271 4891 2294 3721 3808 23 790 

CA 9761 3310 3129 9219 3092 534 10 623 7085 13 364 12 345 72 462 

CO 2033 1387 997 2158 708 199 2896 1654 1541 2889 16 461 

CT 611 403 489 618 510 65 1245 1194 817 1271 7223 

DC 1174 71 111 1462 112 4 104 191 34 830 4092 

DE 70 155 124 224 119 16 237 290 160 323 1719 

FL 21 397 3399 2979 9031 3124 678 11 904 7760 9692 12 748 82 712 

GA 3696 1551 1510 3630 1212 331 5893 5580 7449 5350 36 202 

HI 1280 91 92 171 59 9 273 92 132 485 2682 

IA 143 639 427 999 657 74 1350 1262 621 1062 7234 

ID 233 372 221 716 230 46 699 636 360 496 4008 

IL 7303 1765 1304 2930 1714 232 5660 3083 6473 4179 34 643 

IN 360 1728 856 1746 1323 255 3302 2558 3771 2415 18 313 

KS 98 533 353 877 295 97 1122 826 513 670 5384 

KY 268 757 643 1167 760 138 1667 1270 2001 1106 9778 

LA 169 650 807 1175 593 135 1736 842 1011 1379 8498 

MA 2959 728 884 1103 632 121 1772 1356 854 2484 12895 

MD 3341 813 826 2802 580 109 1549 1527 1989 3388 16 924 

ME 64 209 166 224 134 34 566 313 281 494 2485 

MI 446 1797 713 1696 1359 200 3245 2058 864 2442 14 820 

MN 1437 1018 473 1633 527 102 2135 1175 803 2342 11 645 

MO 875 940 881 1226 780 158 2513 1626 819 1972 11 791 

MS 150 336 479 631 411 55 1166 743 1593 692 6255 

MT 45 122 118 149 94 18 253 174 76 142 1190 

NC 1607 1362 1178 3368 1119 230 4472 3418 1910 3520 22 185 

ND 7 118 91 138 113 14 331 174 57 100 1145 

NE 147 453 303 631 331 54 1149 514 340 676 4599 

NH 141 227 226 276 154 51 648 411 191 438 2763 

NJ 2807 796 943 1235 774 112 2494 2627 3008 2587 17 382 

NM 89 247 418 617 350 62 765 752 292 491 4083 

NV 2867 528 2963 1626 1195 157 2382 960 1669 3231 17 579 

NY 11 622 1639 1959 3330 1075 210 3633 2247 1286 3354 30 354 

OH 635 2452 925 2674 1266 372 5132 4452 3382 3243 24 533 

OK 115 794 512 763 878 141 1364 1179 932 1271 7950 

OR 1253 918 360 922 383 68 1382 651 1142 1648 8727 

PA 1503 1908 1406 2424 1354 219 3762 3660 3512 3556 23 305 

RI 238 60 192 251 81 26 278 197 114 236 1674 

SC 1981 746 563 1539 539 168 2600 2222 1101 2132 13 590 

SD 13 119 86 257 126 13 341 268 88 205 1515 

TN 987 1036 683 2296 733 199 3581 1809 2698 2337 16 360 

TX 5548 4508 3571 8328 3325 849 13 121 12 693 10 609 9676 72 230 

UT 622 569 314 1365 475 76 1424 1269 1274 1201 8590 

VA 3502 1011 1361 3693 1096 200 3014 2387 1826 4406 22 495 

VT 161 99 96 113 71 6 63 136 88 165 998 

WA 3397 1085 871 2435 833 107 2504 1841 1880 3598 18 551 

WI 906 1519 583 1556 746 137 2489 1129 882 1981 11 928 

WV 65 215 148 193 117 39 668 484 179 288 2397 

WY 4 72 166 66 127 9 158 254 67 228 1151 

Total 100 111 48 059 41 007 92 089 38 550 7661 128 609 94 383 98 773 118 693 767 935 

153
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Building Type, New Construction, and Emissions Rates 

Table A-3 New Commercial Building Construction Floor Area for 2003 through 

2007 by State and Building Type (I-P) 

State Building Construction Floor A

Apartment Healthcare Hotel Office Public Assembly Restaurant Retail 

rea (1,000 ft2) 

School Warehouse No Prototype Total 

AK 201 1401 1357 2428 1190 137 2240 2484 1356 2787 15 581 

AL 8619 7587 9184 16 191 6876 1821 26 748 16 514 9060 18 729 121 329 

AR 1272 5000 5198 6962 3611 829 14 624 13 936 3609 8768 63 810 

AZ 11 223 16 195 11 272 43 383 12 701 2918 52 646 24 692 40 052 40 986 256 068 

CA 105 071 35 633 33 678 99 228 33 281 5747 114 344 76 262 143 853 132 882 779 978 

CO 21 885 14 926 10 735 23 225 7618 2142 31 177 17 804 16 582 31 094 177 186 

CT 6582 4333 5261 6651 5485 698 13 403 12 856 8798 13 679 77 746 

DC 12 636 769 1199 15 734 1202 38 1122 2051 363 8934 44 047 

DE 755 1672 1330 2410 1282 173 2551 3126 1722 3480 18 501 

FL 230 315 36 591 32 071 97 212 33 622 7299 128 133 83 524 104 327 137 213 890 306 

GA 39 780 16 699 16 254 39 076 13 043 3563 63 430 60 062 80 180 57 586 389 672 

HI 13 773 979 989 1838 630 95 2939 985 1417 5220 28 865 

IA 1542 6875 4598 10 749 7069 796 14 534 13 586 6688 11 426 77 863 

ID 2506 4001 2375 7703 2478 493 7526 6847 3876 5343 43 147 

IL 78 609 18 998 14 037 31 542 18 451 2497 60 928 33 180 69 674 44 977 372 893 

IN 3875 18 600 9210 18 791 14 242 2747 35 539 27 535 40 591 25 992 197 123 

KS 1057 5734 3795 9442 3178 1039 12 076 8892 5521 7216 57 950 

KY 2888 8150 6922 12 558 8185 1489 17 941 13 672 21 538 11 906 105 248 

LA 1823 7001 8689 12 647 6386 1454 18 681 9061 10 886 14 841 91 469 

MA 31 854 7832 9516 11 868 6808 1306 19 079 14 599 9197 26 742 138 802 

MD 35 967 8750 8888 30 163 6242 1173 16 672 16 432 21 414 36 463 182 163 

ME 687 2245 1791 2411 1441 368 6088 3374 3021 5320 26 745 

MI 4800 19 346 7671 18 251 14 629 2153 34 934 22 151 9305 26 283 159 523 

MN 15 465 10 954 5093 17 575 5673 1098 22 985 12 643 8643 25 212 125 342 

MO 9420 10 121 9483 13 197 8395 1705 27 054 17 497 8818 21 226 126 915 

MS 1613 3618 5153 6789 4423 587 12 551 7999 17 146 7447 67 326 

MT 481 1313 1265 1602 1007 195 2723 1871 821 1533 12 810 

NC 17 294 14 663 12 678 36 249 12 044 2481 48 139 36 794 20 559 37 891 238 792 

ND 76 1265 982 1490 1221 155 3567 1871 617 1077 12 320 

NE 1586 4880 3263 6790 3562 577 12 369 5533 3660 7279 49 498 

NH 1523 2440 2437 2974 1653 548 6970 4421 2059 4717 29 741 

NJ 30 209 8563 10 145 13 295 8335 1210 26 842 28 280 32 383 27 841 187 103 

NM 957 2655 4499 6636 3770 670 8235 8097 3142 5290 43 950 

NV 30 856 5684 31 894 17 504 12 863 1691 25 644 10 337 17 969 34 776 189 218 

NY 125 095 17 639 21 083 35 842 11 572 2259 39 107 24 186 13 845 36 104 326 732 

OH 6832 26 393 9959 28 780 13 630 4004 55 245 47 919 36 400 34 909 264 071 

OK 1242 8547 5511 8216 9450 1523 14 686 12 691 10 032 13 680 85 577 

OR 13 492 9885 3878 9927 4118 728 14 881 7004 12 291 17 738 93 941 

PA 16 177 20 535 15 135 26 096 14 577 2361 40 489 39 397 37 805 38 280 250 852 

RI 2559 649 2069 2707 877 278 2990 2125 1228 2540 18 021 

SC 21 321 8033 6056 16 562 5801 1810 27 984 23 920 11 848 22 949 146 284 

SD 142 1285 922 2767 1354 138 3668 2884 950 2202 16 312 

TN 10 621 11 152 7347 24 718 7891 2145 38 548 19 476 29 045 25 152 176 095 

TX 59 723 48 519 38 437 89 641 35 794 9142 141 238 136 629 114 193 104 156 777 473 

UT 6695 6123 3384 14 698 5110 822 15 331 13 657 13 716 12 926 92 462 

VA 37 694 10 887 14 646 39 749 11 794 2149 32 438 25 691 19 659 47 422 242 129 

VT 1736 1063 1030 1214 765 68 674 1463 946 1777 10 737 

WA 36 566 11 683 9378 26 209 8964 1147 26 954 19 817 20 236 38 731 199 685 

WI 9754 16 350 6273 16 751 8030 1474 26 793 12 148 9497 21 325 128 395 

WV 697 2314 1592 2081 1259 421 7191 5215 1930 3098 25 797 

WY 42 774 1787 713 1370 97 1696 2737 718 2453 12 387 

Total 1 077 585 517 302 441 399 991 233 414 953 82 459 1 384 339 1 015 925 1 063 186 1 277 597 8 265 977 

154
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Building Type, New Construction, and Emissions Rates 

Table A-4 New Commercial Building Construction Share by State and Building 

Type 

State 

Percentage of Building Construction Floor Area 

Apartment Healthcare Hotel Office Public 

Assembly 

7.6 % 

Restaurant Retail School Warehouse No 

Prototype 

17.9 % 

Total Rep. by 

Study 

AK 1.3 % 9.0 % 8.7 % 15.6 % 0.9 % 14.4 % 15.9 % 8.7 % 100.0 % 56.8 % 

AL 7.1 % 6.3 % 7.6 % 13.3 % 5.7 % 1.5 % 22.0 % 13.6 % 7.5 % 15.4 % 100.0 % 65.2 % 

AR 2.0 % 7.8 % 8.1 % 10.9 % 5.7 % 1.3 % 22.9 % 21.8 % 5.7 % 13.7 % 100.0 % 67.1 % 

AZ 4.4 % 6.3 % 4.4 % 16.9 % 5.0 % 1.1 % 20.6 % 9.6 % 15.6 % 16.0 % 100.0 % 57.1 % 

CA 13.5 % 4.6 % 4.3 % 12.7 % 4.3 % 0.7 % 14.7 % 9.8 % 18.4 % 17.0 % 100.0 % 55.7 % 

CO 12.4 % 8.4 % 6.1 % 13.1 % 4.3 % 1.2 % 17.6 % 10.0 % 9.4 % 17.5 % 100.0 % 60.4 % 

CT 8.5 % 5.6 % 6.8 % 8.6 % 7.1 % 0.9 % 17.2 % 16.5 % 11.3 % 17.6 % 100.0 % 58.5 % 

DC 28.7 % 1.7 % 2.7 % 35.7 % 2.7 % 0.1 % 2.5 % 4.7 % 0.8 % 20.3 % 100.0 % 74.4 % 

DE 4.1 % 9.0 % 7.2 % 13.0 % 6.9 % 0.9 % 13.8 % 16.9 % 9.3 % 18.8 % 100.0 % 55.9 % 

FL 25.9 % 4.1 % 3.6 % 10.9 % 3.8 % 0.8 % 14.4 % 9.4 % 11.7 % 15.4 % 100.0 % 65.0 % 

GA 10.2 % 4.3 % 4.2 % 10.0 % 3.3 % 0.9 % 16.3 % 15.4 % 20.6 % 14.8 % 100.0 % 57.0 % 

HI 47.7 % 3.4 % 3.4 % 6.4 % 2.2 % 0.3 % 10.2 % 3.4 % 4.9 % 18.1 % 100.0 % 71.4 % 

IA 2.0 % 8.8 % 5.9 % 13.8 % 9.1 % 1.0 % 18.7 % 17.4 % 8.6 % 14.7 % 100.0 % 58.8 % 

ID 5.8 % 9.3 % 5.5 % 17.9 % 5.7 % 1.1 % 17.4 % 15.9 % 9.0 % 12.4 % 100.0 % 63.6 % 

IL 21.1 % 5.1 % 3.8 % 8.5 % 4.9 % 0.7 % 16.3 % 8.9 % 18.7 % 12.1 % 100.0 % 59.2 % 

IN 2.0 % 9.4 % 4.7 % 9.5 % 7.2 % 1.4 % 18.0 % 14.0 % 20.6 % 13.2 % 100.0 % 49.6 % 

KS 1.8 % 9.9 % 6.5 % 16.3 % 5.5 % 1.8 % 20.8 % 15.3 % 9.5 % 12.5 % 100.0 % 62.6 % 

KY 2.7 % 7.7 % 6.6 % 11.9 % 7.8 % 1.4 % 17.0 % 13.0 % 20.5 % 11.3 % 100.0 % 52.7 % 

LA 2.0 % 7.7 % 9.5 % 13.8 % 7.0 % 1.6 % 20.4 % 9.9 % 11.9 % 16.2 % 100.0 % 57.2 % 

MA 22.9 % 5.6 % 6.9 % 8.6 % 4.9 % 0.9 % 13.7 % 10.5 % 6.6 % 19.3 % 100.0 % 63.6 % 

MD 19.7 % 4.8 % 4.9 % 16.6 % 3.4 % 0.6 % 9.2 % 9.0 % 11.8 % 20.0 % 100.0 % 60.0 % 

ME 2.6 % 8.4 % 6.7 % 9.0 % 5.4 % 1.4 % 22.8 % 12.6 % 11.3 % 19.9 % 100.0 % 55.0 % 

MI 3.0 % 12.1 % 4.8 % 11.4 % 9.2 % 1.3 % 21.9 % 13.9 % 5.8 % 16.5 % 100.0 % 56.4 % 

MN 12.3 % 8.7 % 4.1 % 14.0 % 4.5 % 0.9 % 18.3 % 10.1 % 6.9 % 20.1 % 100.0 % 59.7 % 

MO 7.4 % 8.0 % 7.5 % 10.4 % 6.6 % 1.3 % 21.3 % 13.8 % 6.9 % 16.7 % 100.0 % 61.7 % 

MS 2.4 % 5.4 % 7.7 % 10.1 % 6.6 % 0.9 % 18.6 % 11.9 % 25.5 % 11.1 % 100.0 % 51.5 % 

MT 3.8 % 10.2 % 9.9 % 12.5 % 7.9 % 1.5 % 21.3 % 14.6 % 6.4 % 12.0 % 100.0 % 63.5 % 

NC 7.2 % 6.1 % 5.3 % 15.2 % 5.0 % 1.0 % 20.2 % 15.4 % 8.6 % 15.9 % 100.0 % 64.3 % 

ND 0.6 % 10.3 % 8.0 % 12.1 % 9.9 % 1.3 % 29.0 % 15.2 % 5.0 % 8.7 % 100.0 % 66.1 % 

NE 3.2 % 9.9 % 6.6 % 13.7 % 7.2 % 1.2 % 25.0 % 11.2 % 7.4 % 14.7 % 100.0 % 60.8 % 

NH 5.1 % 8.2 % 8.2 % 10.0 % 5.6 % 1.8 % 23.4 % 14.9 % 6.9 % 15.9 % 100.0 % 63.5 % 

NJ 16.1 % 4.6 % 5.4 % 7.1 % 4.5 % 0.6 % 14.3 % 15.1 % 17.3 % 14.9 % 100.0 % 58.8 % 

NM 2.2 % 6.0 % 10.2 % 15.1 % 8.6 % 1.5 % 18.7 % 18.4 % 7.1 % 12.0 % 100.0 % 66.2 % 

NV 16.3 % 3.0 % 16.9 % 9.3 % 6.8 % 0.9 % 13.6 % 5.5 % 9.5 % 18.4 % 100.0 % 62.3 % 

NY 38.3 % 5.4 % 6.5 % 11.0 % 3.5 % 0.7 % 12.0 % 7.4 % 4.2 % 11.1 % 100.0 % 75.8 % 

OH 2.6 % 10.0 % 3.8 % 10.9 % 5.2 % 1.5 % 20.9 % 18.1 % 13.8 % 13.2 % 100.0 % 57.8 % 

OK 1.5 % 10.0 % 6.4 % 9.6 % 11.0 % 1.8 % 17.2 % 14.8 % 11.7 % 16.0 % 100.0 % 51.3 % 

OR 14.4 % 10.5 % 4.1 % 10.6 % 4.4 % 0.8 % 15.8 % 7.5 % 13.1 % 18.9 % 100.0 % 53.1 % 

PA 6.4 % 8.2 % 6.0 % 10.4 % 5.8 % 0.9 % 16.1 % 15.7 % 15.1 % 15.3 % 100.0 % 55.7 % 

RI 14.2 % 3.6 % 11.5 % 15.0 % 4.9 % 1.5 % 16.6 % 11.8 % 6.8 % 14.1 % 100.0 % 70.6 % 

SC 14.6 % 5.5 % 4.1 % 11.3 % 4.0 % 1.2 % 19.1 % 16.4 % 8.1 % 15.7 % 100.0 % 66.8 % 

SD 0.9 % 7.9 % 5.7 % 17.0 % 8.3 % 0.8 % 22.5 % 17.7 % 5.8 % 13.5 % 100.0 % 64.5 % 

TN 6.0 % 6.3 % 4.2 % 14.0 % 4.5 % 1.2 % 21.9 % 11.1 % 16.5 % 14.3 % 100.0 % 58.4 % 

TX 7.7 % 6.2 % 4.9 % 11.5 % 4.6 % 1.2 % 18.2 % 17.6 % 14.7 % 13.4 % 100.0 % 61.1 % 

UT 7.2 % 6.6 % 3.7 % 15.9 % 5.5 % 0.9 % 16.6 % 14.8 % 14.8 % 14.0 % 100.0 % 59.0 % 

VA 15.6 % 4.5 % 6.0 % 16.4 % 4.9 % 0.9 % 13.4 % 10.6 % 8.1 % 19.6 % 100.0 % 62.9 % 

VT 16.2 % 9.9 % 9.6 % 11.3 % 7.1 % 0.6 % 6.3 % 13.6 % 8.8 % 16.6 % 100.0 % 57.6 % 

WA 18.3 % 5.9 % 4.7 % 13.1 % 4.5 % 0.6 % 13.5 % 9.9 % 10.1 % 19.4 % 100.0 % 60.1 % 

WI 7.6 % 12.7 % 4.9 % 13.0 % 6.3 % 1.1 % 20.9 % 9.5 % 7.4 % 16.6 % 100.0 % 57.0 % 

WV 2.7 % 9.0 % 6.2 % 8.1 % 4.9 % 1.6 % 27.9 % 20.2 % 7.5 % 12.0 % 100.0 % 66.7 % 

WY 0.3 % 6.2 % 14.4 % 5.8 % 11.1 % 0.8 % 13.7 % 22.1 % 5.8 % 19.8 % 100.0 % 57.1 % 

Total 13.0 % 6.3 % 5.3 % 12.0 % 5.0 % 1.0 % 16.7 % 12.3 % 12.9 % 15.5 % 100.0 % 60.4 % 

155
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Building Type, New Construction, and Emissions Rates 

Table A-5 CO2, CH4, and N2O Emissions Rates Electricity Generation by State 

CO2 CH4 N2O CO2 CH4 N2O 

State (t/GWh) (t/GWh) (t/GWh) State (t/GWh) (t/GWh) (t/GWh) 

AK 603.4 57.9 1.9 MT 542.8 30.1 0.4 

AL 804.2 42.7 0.5 NC 616.6 30.5 0.2 

AR 695.9 58.6 1.7 ND 851.1 40.4 0.2 

AZ 746.9 53.2 1.2 NE 851.1 40.4 0.2 

CA 450.0 45.8 1.5 NH 550.4 47.0 1.4 

CO 938.8 54.0 0.8 NJ 618.7 33.4 0.4 

CT 550.4 47.0 1.4 NM 778.5 55.3 1.3 

DE 618.7 33.4 0.4 NV 465.6 27.6 0.4 

FL 767.5 57.2 1.5 NY 480.7 32.3 0.8 

GA 804.2 42.7 0.5 OH 835.7 38.9 0.2 

HI 807.1 28.0 0.1 OK 904.8 63.9 1.4 

IA 851.1 40.4 0.2 OR 465.6 27.6 0.4 

ID 465.6 27.6 0.4 PA 672.9 34.7 0.4 

IL 948.3 44.4 0.2 RI 550.4 47.0 1.4 

IN 835.7 38.9 0.2 SC 616.6 30.5 0.2 

KS 926.0 44.8 0.3 SD 851.1 40.4 0.2 

KY 781.9 36.9 0.2 TN 781.9 36.9 0.2 

LA 719.2 59.2 1.6 TX 790.9 65.8 1.8 

MA 550.4 47.0 1.4 UT 465.6 27.6 0.4 

MD 618.7 33.4 0.4 VA 689.6 33.3 0.2 

ME 550.4 47.0 1.4 VT 550.4 47.0 1.4 

MI 861.4 46.8 0.6 WA 465.6 27.6 0.4 

MN 851.1 40.4 0.2 WI 860.7 44.1 0.4 

MO 939.4 44.6 0.2 WV 835.7 38.9 0.2 

MS 709.8 48.3 1.0 WY 623.7 36.4 0.5 

156
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIRDS Results by Building Type for the Nationwide Adoption of the LEC and ASHRAE 90.1-2007 

Designs 

B BIRDS Results by Building Type for the Nationwide Adoption of the 

LEC and ASHRAE 90.1-2007 Designs 

Table B-1 4-Story Apartment Building Summary Table for LEC and 10-Year 

Study Period 

Percentage Change Percentage Change State State 

Energy Use Energy Cost Carbon LCC Energy Use Energy Cost Carbon LCC 

AK -12.7 -31.2 -25.0 -1.7 MT -9.6 -15.2 -14.5 0.6 

AL -35.2 -40.3 -42.9 -3.4 NC -13.5 -17.0 -18.1 0.4 

AR -29.0 -36.6 -39.4 -1.8 ND -17.5 -30.8 -33.4 -1.0 

AZ -26.6 -31.1 -32.4 -1.6 NE -9.8 -16.3 -17.2 0.7 

CA -16.1 -22.5 -19.8 0.2 NH -9.5 -15.8 -14.7 -0.3 

CO -21.9 -36.2 -37.9 -1.2 NJ -10.3 -17.8 -16.0 0.4 

CT -9.5 -18.5 -15.1 -0.1 NM -13.6 -20.0 -20.0 0.5 

DE -10.4 -15.0 -16.0 -0.2 NV -14.5 -20.7 -18.8 -0.1 

FL -16.6 -17.7 -17.8 -0.3 NY -9.2 -17.5 -13.8 0.0 

GA -14.3 -17.7 -18.8 0.4 OH -9.6 -16.0 -17.1 0.5 

HI -20.4 -20.4 -20.4 -1.7 OK -27.2 -35.1 -40.8 -1.3 

IA -9.8 -15.8 -16.8 0.5 OR -10.0 -15.0 -15.4 1.1 

ID -10.2 -14.8 -14.9 0.8 PA -9.5 -14.9 -16.0 0.6 

IL -9.4 -17.1 -17.1 0.3 RI -9.2 -15.5 -15.1 0.2 

IN -10.1 -16.0 -17.1 0.6 SC -18.0 -22.6 -23.2 -0.1 

KS -24.9 -35.3 -39.1 -1.6 SD -21.2 -34.1 -35.9 -1.7 

KY -11.5 -15.6 -17.9 0.7 TN -16.1 -20.5 -21.3 -0.1 

LA -15.4 -17.6 -18.3 0.5 TX -15.0 -18.6 -18.6 0.0 

MA -9.1 -16.8 -14.8 0.1 UT -10.7 -17.6 -15.7 0.7 

MD -10.9 -17.1 -16.4 0.2 VA -12.6 -17.0 -18.1 0.5 

ME -19.9 -32.9 -31.9 -2.6 VT -9.5 -15.5 -14.6 -0.2 

MI -8.5 -15.2 -16.3 0.4 WA -8.8 -12.8 -14.0 1.2 

MN -13.8 -18.0 -18.6 0.2 WI -9.5 -15.9 -16.4 0.4 

MO -25.4 -33.3 -38.6 -1.0 WV -25.3 -29.8 -38.9 -0.8 

MS -35.7 -42.4 -42.6 -3.3 WY -22.7 -36.6 -36.4 -1.4 

Avg. -14.8 -21.2 -21.6 -0.1 

157
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIRDS Results by Building Type for the Nationwide Adoption of the LEC and ASHRAE 90.1-2007 

Designs 

Table B-2 6-Story Apartment Building Summary Table for LEC and 10-Year 

Study Period 

Percentage Change Percentage Change State State
 

Energy Use Energy Cost Carbon LCC
 Energy Use Energy Carbon LCC 

Cost 

AK -12.2 -31.1 -24.8 -1.5 MT -9.5 -15.1 -14.4 0.6 

AL -35.6 -41.2 -44.1 -3.5 NC -14.8 -19.2 -20.6 0.2 

AR -29.8 -37.9 -40.8 -1.9 ND -17.2 -30.5 -33.1 -0.9 

AZ -27.1 -32.5 -34.0 -1.7 NE -11.2 -19.5 -20.5 0.6 

CA -18.2 -26.1 -22.8 -0.1 NH -9.3 -15.4 -14.4 -0.3 

CO -22.5 -37.7 -39.5 -1.2 NJ -11.4 -20.6 -18.5 0.2 

CT -10.6 -21.8 -17.7 -0.4 NM -15.1 -23.0 -23.0 0.3 

DE -11.2 -17.0 -18.2 -0.4 NV -14.9 -22.9 -20.5 -0.1 

FL -17.5 -18.9 -19.0 -0.4 NY -9.6 -19.4 -15.1 -0.1 

GA -15.5 -19.5 -20.9 0.3 OH -10.6 -18.5 -19.9 0.4 

HI -20.7 -20.7 -20.7 -1.6 OK -28.1 -36.5 -42.6 -1.5 

IA -10.6 -17.6 -18.7 0.5 OR -10.9 -17.1 -17.7 1.0 

ID -11.1 -16.5 -16.5 0.8 PA -10.4 -17.1 -18.5 0.5 

IL -10.5 -20.0 -20.1 0.1 RI -10.0 -17.9 -17.4 0.0 

IN -11.3 -18.7 -20.1 0.5 SC -18.9 -24.4 -25.1 -0.2 

KS -25.9 -37.4 -41.4 -1.8 SD -20.6 -33.5 -35.4 -1.5 

KY -13.4 -18.6 -21.4 0.5 TN -17.3 -22.9 -23.9 -0.3 

LA -16.5 -19.1 -20.0 0.4 TX -16.3 -20.6 -20.6 -0.2 

MA -9.8 -19.5 -17.0 0.0 UT -11.9 -20.5 -18.2 0.6 

MD -12.1 -19.9 -19.0 0.0 VA -14.4 -20.0 -21.3 0.3 

ME -19.3 -32.3 -31.4 -2.4 VT -9.2 -15.1 -14.2 -0.1 

MI -8.9 -16.7 -17.9 0.3 WA -9.4 -14.4 -15.8 1.2 

MN -13.0 -17.3 -17.9 0.4 WI -9.3 -15.5 -16.0 0.5 

MO -26.5 -35.2 -40.9 -1.1 WV -26.2 -31.2 -41.0 -0.8 

MS -36.2 -43.3 -43.5 -3.4 WY -22.5 -36.3 -36.2 -1.3 

Avg. -9.5 -15.1 -23.3 -0.2 

158
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIRDS Results by Building Type for the Nationwide Adoption of the LEC and ASHRAE 90.1-2007 

Designs 

Table B-3 4-Story Dormitory Summary Table for LEC and 10-Year Study Period 

State Percentage Change State Percentage Change 

Energy Use Energy Cost Carbon LCC Energy Use Energy Carbon LCC 

Cost 

AK -18.1 -34.8 -29.3 -2.4 MT -12.9 -17.1 -16.6 -1.2 

AL -36.7 -41.7 -44.2 -2.9 NC -14.8 -17.7 -18.5 -0.7 

AR -28.8 -37.1 -40.0 -4.9 ND -21.6 -33.7 -36.0 0.3 

AZ -29.1 -32.1 -32.9 -1.6 NE -11.7 -17.2 -17.9 -0.2 

CA -18.2 -22.3 -20.6 -1.3 NH -12.2 -17.0 -16.2 -1.7 

CO -24.9 -36.6 -37.9 -4.2 NJ -12.3 -18.6 -17.2 -0.8 

CT -11.2 -18.9 -16.1 -1.6 NM -15.3 -19.8 -19.8 -1.6 

DE -12.3 -16.3 -17.2 -0.5 NV -17.1 -21.1 -19.9 -1.9 

FL -17.4 -18.4 -18.5 -2.1 NY -11.1 -18.2 -15.1 -1.5 

GA -15.1 -18.1 -19.1 -1.2 OH -11.2 -16.9 -17.8 -1.2 

HI -22.1 -22.1 -22.1 -3.6 OK -27.6 -36.1 -42.2 0.0 

IA -11.7 -16.7 -17.5 -0.2 OR -12.7 -16.7 -17.0 -1.0 

ID -12.7 -16.4 -16.5 -1.2 PA -11.1 -15.9 -16.8 -0.8 

IL -11.1 -17.8 -17.8 -0.3 RI -11.3 -16.7 -16.4 -1.4 

IN -11.8 -16.9 -17.9 -0.4 SC -16.9 -21.7 -22.3 -1.3 

KS -27.6 -37.1 -40.4 0.3 SD -24.0 -35.7 -37.3 -1.4 

KY -12.9 -16.4 -18.3 -1.0 TN -17.3 -20.4 -20.9 -1.1 

LA -15.5 -17.8 -18.5 -0.8 TX -15.5 -18.6 -18.7 -0.9 

MA -11.1 -17.8 -16.1 -1.3 UT -12.8 -18.2 -16.8 -1.2 

MD -12.5 -17.8 -17.2 -0.2 VA -14.3 -17.9 -18.7 -0.7 

ME -24.4 -35.6 -34.9 -1.6 VT -11.9 -16.7 -15.9 -1.6 

MI -10.7 -16.5 -17.4 -1.2 WA -11.6 -15.0 -16.0 -0.5 

MN -19.0 -20.7 -20.9 -1.5 WI -12.0 -17.0 -17.4 -0.8 

MO -27.4 -35.0 -39.8 0.2 WV -26.7 -31.0 -38.8 -3.3 

MS -39.0 -44.2 -44.4 -1.8 WY -26.9 -38.4 -38.3 -0.9 

Avg. -16.9 -22.2 -22.6 -1.2 

159
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIRDS Results by Building Type for the Nationwide Adoption of the LEC and ASHRAE 90.1-2007 

Designs 

Table B-4 6-Story Dormitory Summary Table for LEC and 10-Year Study Period 

State Percentage Change State Percentage Change 

Energy Use Energy Cost Carbon LCC Energy Use Energy Carbon LCC 

Cost 

AK -11.1 -30.0 -23.7 -2.2 MT -8.6 -13.6 -12.9 0.3 

AL -37.9 -43.7 -46.7 -4.9 NC -14.7 -19.1 -20.4 -0.1 

AR -30.8 -39.1 -42.1 -2.9 ND -16.6 -28.8 -31.2 -1.6 

AZ -28.3 -33.6 -35.1 -2.4 NE -10.9 -18.8 -19.8 0.3 

CA -17.9 -26.3 -22.7 -0.4 NH -8.4 -13.8 -12.9 -0.5 

CO -20.7 -36.0 -37.9 -1.8 NJ -11.4 -20.4 -18.3 -0.2 

CT -10.4 -21.2 -17.2 -0.7 NM -15.2 -22.8 -22.9 -0.1 

DE -11.3 -16.9 -18.0 -0.8 NV -14.1 -22.1 -19.6 -0.4 

FL -18.4 -20.0 -20.1 -0.9 NY -9.1 -18.3 -14.3 -0.4 

GA -15.5 -19.7 -21.2 -0.1 OH -10.3 -17.9 -19.2 0.1 

HI -23.0 -23.0 -23.0 -2.5 OK -29.9 -38.5 -44.8 -2.6 

IA -10.0 -16.4 -17.4 0.2 OR -10.6 -16.7 -17.1 0.7 

ID -10.6 -15.6 -15.7 0.5 PA -10.3 -16.8 -18.0 0.2 

IL -10.3 -19.4 -19.4 -0.2 RI -9.7 -17.2 -16.7 -0.3 

IN -11.0 -18.1 -19.4 0.2 SC -20.2 -26.0 -26.8 -0.7 

KS -24.8 -36.3 -40.4 -2.6 SD -17.3 -30.6 -32.5 -2.0 

KY -12.9 -17.9 -20.6 0.2 TN -16.1 -21.9 -22.9 -0.5 

LA -16.7 -19.6 -20.6 0.0 TX -16.3 -20.9 -20.9 -0.6 

MA -9.5 -18.7 -16.4 -0.3 UT -12.0 -20.1 -18.0 0.3 

MD -12.0 -19.7 -18.8 -0.4 VA -14.2 -19.6 -20.8 0.0 

ME -18.0 -30.6 -29.7 -3.1 VT -8.2 -13.4 -12.6 -0.3 

MI -8.5 -15.9 -17.1 0.1 WA -9.2 -14.1 -15.5 0.9 

MN -11.3 -15.2 -15.7 0.2 WI -8.2 -13.7 -14.2 0.2 

MO -26.0 -34.9 -40.6 -1.9 WV -24.4 -29.6 -39.1 -1.4 

MS -38.2 -45.6 -45.9 -4.7 WY -19.1 -33.4 -33.2 -1.8 

Avg. -15.2 -22.4 -22.8 -0.6 

160
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIRDS Results by Building Type for the Nationwide Adoption of the LEC and ASHRAE 90.1-2007 

Designs 

Table B-5 15-Story Hotel Building Summary Table for LEC and 10-Year Study 

Period 

State Percentage Change State Percentage Change 

Energy Use Energy Cost Carbon LCC Energy Use Energy Carbon LCC 

Cost 

AK -6.9 -23.5 -18.0 -1.8 MT -9.4 -11.5 -11.3 0.4 

AL -30.3 -36.2 -39.2 -3.0 NC -14.9 -18.4 -19.4 0.3 

AR -21.5 -32.1 -36.0 -1.6 ND -10.0 -20.8 -22.8 -1.1 

AZ -23.1 -26.4 -27.3 -1.0 NE -12.7 -18.9 -19.7 0.6 

CA -18.2 -24.5 -21.8 0.0 NH -8.9 -11.2 -10.8 -0.2 

CO -16.0 -28.8 -30.3 -1.1 NJ -13.1 -20.2 -18.6 0.1 

CT -12.7 -21.6 -18.3 -0.5 NM -15.7 -21.1 -21.1 0.4 

DE -13.1 -17.6 -18.5 -0.6 NV -8.8 -14.7 -13.0 0.7 

FL -16.7 -18.8 -19.0 -0.1 NY -11.2 -18.0 -15.0 -0.2 

GA -14.5 -18.5 -19.9 0.4 OH -11.8 -18.1 -19.2 0.4 

HI -18.0 -18.1 -18.1 -0.6 OK -19.7 -29.9 -37.5 -1.2 

IA -11.0 -15.3 -16.0 0.5 OR -13.8 -18.4 -18.8 0.9 

ID -12.3 -15.9 -15.9 0.7 PA -11.8 -17.1 -18.2 0.4 

IL -11.8 -19.2 -19.2 0.2 RI -12.1 -18.1 -17.7 -0.1 

IN -12.3 -18.1 -19.2 0.5 SC -8.5 -14.6 -15.4 0.9 

KS -19.7 -29.4 -32.9 -1.5 SD -11.8 -21.8 -23.2 -1.3 

KY -13.7 -17.6 -19.8 0.6 TN -9.6 -13.6 -14.3 0.8 

LA -14.5 -18.1 -19.3 0.6 TX -14.9 -19.6 -19.6 0.0 

MA -11.8 -19.3 -17.4 -0.1 UT -14.2 -20.2 -18.6 0.6 

MD -13.4 -19.4 -18.7 -0.1 VA -14.9 -18.8 -19.8 0.4 

ME -14.0 -23.1 -22.5 -2.3 VT -9.0 -11.3 -11.0 -0.1 

MI -10.1 -15.5 -16.4 0.2 WA -12.3 -16.2 -17.2 1.1 

MN -6.8 -6.8 -6.8 0.9 WI -8.9 -11.2 -11.4 0.4 

MO -19.8 -27.5 -32.6 -0.9 WV -18.9 -23.4 -32.3 -0.6 

MS -34.4 -37.0 -37.1 -2.8 WY -13.8 -24.7 -24.6 -1.3 

Avg. -13.9 -19.6 -20.0 -0.1 

161
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIRDS Results by Building Type for the Nationwide Adoption of the LEC and ASHRAE 90.1-2007 

Designs 

Table B-6 2-Story High School Summary Table for LEC and 10-Year Study 

Period 

State Percentage Change State Percentage Change 

Energy Use Energy Cost Carbon LCC Energy Use Energy Carbon LCC 

Cost 

AK -7.7 -17.8 -14.0 -1.6 MT -9.7 -13.9 -13.3 -0.6 

AL -23.6 -29.4 -32.7 -3.3 NC -10.5 -16.2 -18.1 -1.1 

AR -16.5 -25.0 -28.5 -1.8 ND -11.1 -18.9 -20.8 -0.9 

AZ -21.5 -27.4 -29.2 -2.8 NE -5.8 -15.0 -16.4 -0.6 

CA -13.7 -23.4 -19.2 -1.8 NH -5.7 -12.3 -11.1 -1.5 

CO -10.6 -23.1 -25.0 -1.9 NJ -6.6 -17.8 -15.0 -1.5 

CT -5.3 -17.9 -12.8 -1.9 NM -9.6 -19.8 -19.9 -1.0 

DE -6.4 -13.3 -14.8 -1.8 NV -9.5 -18.2 -15.4 -1.5 

FL -21.2 -23.4 -23.7 -1.9 NY -6.2 -16.7 -11.8 -1.6 

GA -12.6 -18.2 -20.3 -1.6 OH -5.6 -14.2 -15.8 -0.8 

HI -26.7 -26.7 -26.7 -4.2 OK -15.0 -22.8 -29.7 -1.3 

IA -6.1 -13.8 -15.2 -0.8 OR -4.9 -11.5 -12.1 0.0 

ID -6.0 -11.8 -11.9 -0.2 PA -5.4 -12.7 -14.3 -0.6 

IL -5.6 -16.4 -16.5 -1.1 RI -5.0 -13.7 -13.0 -0.9 

IN -6.4 -14.8 -16.6 -0.8 SC -13.8 -19.8 -20.6 -1.3 

KS -13.7 -23.4 -27.7 -1.5 SD -10.9 -20.0 -21.7 -1.8 

KY -8.0 -14.1 -17.8 -0.9 TN -12.9 -19.9 -21.3 -1.7 

LA -15.4 -19.5 -21.0 -0.8 TX -14.7 -21.0 -21.1 -1.7 

MA -4.6 -15.2 -12.3 -1.1 UT -5.9 -15.6 -12.8 -0.8 

MD -7.2 -16.9 -15.6 -1.7 VA -9.2 -16.4 -18.3 -0.6 

ME -10.7 -18.9 -18.3 -1.9 VT -5.9 -12.1 -11.0 -1.4 

MI -4.6 -12.7 -14.2 -0.8 WA -4.2 -9.4 -10.9 0.2 

MN -9.2 -14.1 -14.9 -1.1 WI -5.9 -12.7 -13.4 -1.1 

MO -14.3 -21.7 -27.7 -1.4 WV -13.3 -17.1 -26.4 -1.3 

MS -26.7 -33.1 -33.4 -3.4 WY -11.5 -21.2 -21.1 -1.3 

Avg. -10.6 -18.0 -18.5 -1.3 

162
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIRDS Results by Building Type for the Nationwide Adoption of the LEC and ASHRAE 90.1-2007 

Designs 

Table B-7 8-Story Office Building Summary Table for LEC and 10-Year Study 

Period 

State Percentage Change State Percentage Change 

Energy Use Energy Cost Carbon LCC Energy Use Energy Carbon LCC 

Cost 

AK -21.3 -25.8 -24.6 0.0 MT -16.9 -18.1 -18.0 -1.5 

AL -31.7 -32.2 -32.4 -0.7 NC -20.2 -20.9 -21.1 -1.9 

AR -30.0 -31.4 -31.9 -5.2 ND -26.0 -28.1 -28.4 1.3 

AZ -28.1 -28.0 -28.0 -2.3 NE -18.5 -21.2 -21.5 -2.2 

CA -21.4 -21.9 -21.8 -2.8 NH -16.9 -18.2 -18.1 -2.2 

CO -28.3 -29.7 -29.9 -5.1 NJ -19.5 -21.4 -21.1 -2.5 

CT -18.3 -21.3 -20.5 -2.7 NM -21.4 -22.5 -22.5 -2.8 

DE -19.7 -21.1 -21.3 -3.2 NV -23.0 -23.4 -23.3 -3.6 

FL -20.1 -20.2 -20.2 -2.6 NY -17.0 -20.1 -19.0 -2.5 

GA -19.5 -20.2 -20.4 -1.7 OH -17.9 -20.6 -20.9 -2.2 

HI -21.3 -21.3 -21.3 -3.6 OK -31.2 -32.9 -34.0 0.9 

IA -17.3 -19.6 -19.8 -1.5 OR -20.9 -22.0 -22.0 -3.0 

ID -19.3 -20.4 -20.4 -2.4 PA -18.0 -20.3 -20.6 -2.4 

IL -17.8 -21.0 -21.0 -2.2 RI -18.9 -21.0 -20.9 -2.4 

IN -18.5 -20.8 -21.1 -2.0 SC -21.7 -21.9 -22.0 -2.2 

KS -32.5 -33.1 -33.3 0.3 SD -26.8 -28.4 -28.6 -0.5 

KY -19.5 -20.8 -21.4 -2.4 TN -23.4 -22.7 -22.6 -3.0 

LA -19.9 -20.2 -20.3 -1.8 TX -19.9 -20.5 -20.5 -2.6 

MA -18.3 -21.1 -20.6 -2.5 UT -20.7 -22.5 -22.1 -2.6 

MD -19.7 -21.4 -21.2 -2.9 VA -20.8 -21.7 -21.9 -2.2 

ME -28.1 -29.2 -29.1 0.0 VT -16.5 -18.0 -17.8 -2.0 

MI -16.7 -19.6 -19.8 -2.2 WA -20.0 -21.1 -21.3 -2.3 

MN -21.4 -19.8 -19.6 -1.3 WI -16.4 -18.0 -18.1 -1.2 

MO -32.3 -32.5 -32.6 0.4 WV -30.1 -30.4 -30.3 -4.8 

MS -32.4 -32.0 -31.9 1.1 WY -29.2 -30.1 -30.0 0.7 

Avg. -21.5 -22.8 -22.8 -2.1 

163
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIRDS Results by Building Type for the Nationwide Adoption of the LEC and ASHRAE 90.1-2007 

Designs 

Table B-8 16-Story Office Building Summary Table for LEC and 10-Year Study 

Period 

State Percentage Change State Percentage Change 

Energy Use Energy Cost Carbon LCC Energy Use Energy Carbon LCC 

Cost 

AK -8.1 -14.9 -12.9 -0.2 MT -11.7 -12.5 -12.5 0.4 

AL -23.3 -25.1 -26.0 -1.0 NC -17.2 -19.1 -19.6 0.4 

AR -18.2 -23.8 -25.7 0.0 ND -9.9 -13.5 -14.1 0.4 

AZ -19.6 -20.5 -20.8 0.0 NE -15.2 -20.2 -20.7 0.8 

CA -19.8 -21.8 -21.0 -0.1 NH -11.3 -12.3 -12.2 -0.6 

CO -15.7 -21.2 -21.7 0.1 NJ -16.0 -21.0 -20.1 -0.1 

CT -15.2 -21.6 -19.6 -0.9 NM -18.9 -21.7 -21.7 0.3 

DE -16.0 -19.4 -19.9 -1.0 NV -12.5 -16.0 -15.1 0.7 

FL -17.6 -18.5 -18.5 -0.2 NY -13.9 -18.7 -16.9 -0.6 

GA -16.5 -18.4 -19.1 0.5 OH -14.4 -19.5 -20.2 0.5 

HI -16.4 -16.4 -16.4 -0.6 OK -17.3 -23.0 -26.9 0.3 

IA -13.0 -16.2 -16.6 0.6 OR -17.8 -20.9 -21.1 1.0 

ID -15.3 -17.7 -17.8 0.9 PA -14.4 -18.9 -19.6 0.4 

IL -13.9 -19.8 -19.8 0.2 RI -15.3 -20.0 -19.7 -0.3 

IN -15.0 -19.7 -20.4 0.6 SC -12.1 -15.5 -15.9 1.0 

KS -17.1 -21.6 -23.1 0.3 SD -10.1 -13.2 -13.6 0.2 

KY -16.2 -19.3 -20.7 0.7 TN -12.3 -15.0 -15.4 0.8 

LA -16.6 -18.3 -18.8 0.7 TX -16.8 -19.1 -19.1 -0.1 

MA -14.4 -20.2 -19.0 -0.3 UT -17.5 -21.7 -20.8 0.6 

MD -16.0 -20.1 -19.7 -0.3 VA -18.0 -20.6 -21.1 0.4 

ME -13.9 -15.9 -15.8 -0.7 VT -11.3 -12.3 -12.2 -0.4 

MI -12.6 -16.9 -17.5 0.2 WA -16.2 -19.1 -19.8 1.4 

MN -8.7 -7.8 -7.7 1.0 WI -10.9 -11.9 -12.0 0.3 

MO -16.3 -20.0 -22.2 0.9 WV -16.9 -19.1 -23.0 0.9 

MS -27.3 -24.8 -24.7 -0.5 WY -12.8 -16.2 -16.1 0.1 

Avg. -15.3 -18.3 -18.5 0.3 

164
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIRDS Results by Building Type for the Nationwide Adoption of the LEC and ASHRAE 90.1-2007 

Designs 

Table B-9 1-Story Retail Store Summary Table for LEC and 10-Year Study 

Period 

Percentage Change Percentage Change State State
 

Energy Use Energy Cost Carbon LCC
 Energy Use Energy Carbon LCC 

Cost 

AK -26.3 -27.3 -26.8 -0.2 MT -16.0 -17.7 -17.5 0.1 

AL -35.1 -35.6 -35.9 -0.9 NC -15.8 -17.2 -17.6 0.1 

AR -29.8 -31.8 -32.5 -1.7 ND -31.8 -33.4 -33.7 0.6 

AZ -31.6 -32.4 -32.6 -1.8 NE -12.5 -16.8 -17.2 0.8 

CA -16.1 -17.8 -17.1 0.0 NH -15.9 -17.8 -17.5 -0.9 

CO -28.4 -32.0 -32.4 -2.0 NJ -13.9 -17.4 -16.7 0.1 

CT -12.3 -16.9 -15.5 -1.7 NM -15.6 -18.9 -18.9 0.1 

DE -14.2 -16.7 -17.1 -0.8 NV -21.0 -21.9 -21.7 -0.6 

FL -17.9 -18.2 -18.2 -0.7 NY -12.4 -16.4 -14.9 -0.6 

GA -15.5 -16.5 -16.8 0.5 OH -12.5 -16.1 -16.6 -0.5 

HI -22.3 -22.3 -22.3 -3.1 OK -30.5 -32.6 -34.0 1.9 

IA -14.3 -17.2 -17.6 0.6 OR -13.2 -15.3 -15.4 0.8 

ID -14.2 -16.3 -16.3 1.2 PA -12.3 -15.4 -15.9 0.1 

IL -12.5 -16.9 -16.9 -0.4 RI -12.4 -15.8 -15.6 -1.5 

IN -13.5 -16.8 -17.4 0.5 SC -20.2 -20.5 -20.5 0.2 

KS -30.6 -33.9 -35.1 1.0 SD -29.9 -33.5 -34.0 -0.9 

KY -14.9 -17.2 -18.3 0.5 TN -23.1 -22.6 -22.5 -0.4 

LA -15.0 -15.5 -15.7 0.7 TX -15.3 -16.5 -16.5 0.0 

MA -11.8 -16.1 -15.2 0.1 UT -13.0 -17.3 -16.3 1.2 

MD -14.3 -17.3 -17.0 -0.1 VA -16.1 -18.2 -18.7 0.5 

ME -31.7 -33.2 -33.1 -1.2 VT -15.7 -17.5 -17.3 -0.8 

MI -12.6 -16.0 -16.4 -0.3 WA -12.3 -13.9 -14.3 1.1 

MN -27.3 -23.9 -23.5 -0.8 WI -15.9 -18.0 -18.1 -1.1 

MO -31.3 -33.5 -34.8 1.7 WV -30.7 -31.6 -32.9 -1.8 

MS -40.6 -38.8 -38.8 -0.3 WY -30.5 -34.0 -34.0 0.4 

Avg. -18.9 -20.9 -21.0 -0.1 

165
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIRDS Results by Building Type for the Nationwide Adoption of the LEC and ASHRAE 90.1-2007 

Designs 

Table B-10 1-Story Restaurant Summary Table for LEC and 10-Year Study 

Period 

State Percentage Change State Percentage Change 

Energy Use Energy Cost Carbon LCC Energy Use Energy Carbon LCC 

Cost 

AK -33.4 -40.1 -37.9 1.0 MT -24.1 -28.9 -28.4 -1.4 

AL -43.9 -46.5 -47.7 -3.4 NC -30.2 -33.0 -33.8 -4.8 

AR -39.8 -44.8 -46.5 -10.3 ND -41.8 -44.2 -44.6 -0.2 

AZ -41.4 -43.6 -44.2 -5.2 NE -24.2 -32.6 -33.5 -3.9 

CA -34.1 -37.5 -36.2 -5.2 NH -24.3 -29.0 -28.3 -4.6 

CO -40.2 -46.3 -47.0 -7.4 NJ -27.3 -34.1 -32.8 -6.3 

CT -24.1 -33.6 -30.6 -4.4 NM -31.4 -36.6 -36.6 -4.3 

DE -27.7 -32.2 -33.0 -8.5 NV -35.1 -38.6 -37.7 -6.0 

FL -30.5 -31.5 -31.6 -5.3 NY -21.7 -31.5 -27.7 -4.3 

GA -30.0 -32.7 -33.6 -4.9 OH -23.3 -31.4 -32.6 -3.4 

HI -34.8 -34.8 -34.8 -6.3 OK -39.7 -45.1 -48.8 -3.1 

IA -23.7 -30.3 -31.2 -4.4 OR -28.5 -33.0 -33.4 -4.5 

ID -26.0 -30.8 -30.9 -2.7 PA -23.7 -30.4 -31.6 -3.4 

IL -23.3 -32.6 -32.6 -4.5 RI -25.0 -31.8 -31.4 -3.8 

IN -24.8 -31.9 -33.1 -4.3 SC -32.0 -34.7 -35.1 -4.2 

KS -40.8 -46.4 -48.3 -1.2 SD -39.0 -43.6 -44.2 -3.0 

KY -27.9 -32.3 -34.3 -5.4 TN -32.9 -35.6 -36.1 -7.7 

LA -29.3 -31.3 -31.9 -6.0 TX -29.8 -33.2 -33.2 -5.9 

MA -23.8 -32.5 -30.7 -3.7 UT -27.1 -34.7 -32.9 -3.8 

MD -27.7 -33.5 -32.9 -9.0 VA -30.3 -34.0 -34.8 -5.4 

ME -43.6 -45.6 -45.5 -2.6 VT -23.6 -28.5 -27.9 -4.3 

MI -22.1 -30.3 -31.4 -3.0 WA -26.4 -30.6 -31.6 -3.9 

MN -37.9 -36.3 -36.1 -5.0 WI -23.6 -28.7 -29.1 -3.3 

MO -39.1 -43.9 -46.8 -3.3 WV -39.3 -41.8 -45.3 -6.4 

MS -46.0 -47.7 -47.7 -1.9 WY -42.3 -46.2 -46.1 1.3 

Avg. -30.7 -35.4 -35.6 -4.2 

166
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIRDS Results by Building Type for the Nationwide Adoption of the LEC and ASHRAE 90.1-2007 

Designs 

Table B-11 4-Story Apartment Building Summary Table for ASHRAE 90.1-2007 

and 10-Year Study Period 

State Percentage Change State Percentage Change 

Energy Use Energy Cost Carbon LCC Energy Use Energy Cost Carbon LCC 

AK -5.6 -20.2 -15.3 -2.3 MS -25.5 -29.7 -29.9 -3.6 

AL -24.3 -27.9 -29.8 -3.6 ND -8.5 -18.8 -20.9 -1.6 

AR -18.7 -24.5 -26.6 -2.5 NV -4.3 -3.7 -3.9 -0.4 

AZ -14.3 -15.9 -16.3 -1.8 OK -17.4 -23.5 -28.0 -2.0 

CO -12.7 -22.0 -23.1 -1.9 SC -4.7 -6.1 -6.3 -0.6 

HI -2.7 -2.7 -2.7 -0.5 SD -12.5 -21.9 -23.3 -2.2 

KS -15.7 -23.0 -25.6 -2.2 TN -3.7 -3.4 -3.3 -0.4 

ME -11.5 -21.3 -20.6 -2.8 WV -15.9 -19.0 -25.3 -1.7 

MN -4.9 -3.5 -3.3 -0.5 WY -13.7 -24.0 -23.9 -2.0 

MO -16.0 -21.6 -25.3 -1.8 Avg. -11.4 -16.7 -17.4 -1.7 

Table B-12 6-Story Apartment Building Summary Table for ASHRAE 90.1-2007 

and 10-Year Study Period 

Percentage Change Percentage Change State State 

Energy Use Energy Cost Carbon LCC Energy Use Energy Cost Carbon LCC 

AK -5.5 -20.3 -15.4 -2.2 MS -25.3 -29.5 -29.7 -3.6 

AL -23.7 -27.6 -29.5 -3.6 ND -8.5 -18.8 -20.8 -1.6 

AR -18.4 -24.3 -26.4 -2.5 NV -3.7 -3.2 -3.4 -0.3 

AZ -13.6 -15.3 -15.7 -1.7 OK -17.0 -23.3 -27.9 -2.1 

CO -12.4 -21.7 -22.8 -1.8 SC -4.1 -5.9 -6.1 -0.5 

HI -2.5 -2.5 -2.5 -0.4 SD -12.1 -21.6 -22.9 -2.1 

KS -15.4 -22.7 -25.3 -2.3 TN -3.1 -2.9 -2.8 -0.3 

ME -11.2 -21.0 -20.3 -2.7 WV -15.4 -18.6 -24.8 -1.6 

MN -4.4 -3.1 -2.9 -0.4 WY -13.3 -23.7 -23.6 -1.9 

MO -15.7 -21.2 -24.9 -1.8 Avg. -11.0 -16.3 -17.1 -1.6 

Table B-13 4-Story Dormitory Summary Table for ASHRAE 90.1-2007 and 10-Year 

Study Period 

Percentage Change Percentage Change State State 

Energy Use Energy Cost Carbon LCC Energy Use Energy Cost Carbon LCC 

AK -6.5 -21.1 -16.3 -1.8 MS -29.2 -32.0 -32.1 -1.0 

AL -25.6 -29.4 -31.2 -1.2 ND -9.3 -20.2 -22.2 1.2 

AR -17.7 -24.5 -26.9 -5.1 NV -5.0 -3.5 -3.9 -0.7 

AZ -16.4 -16.9 -17.0 -0.1 OK -16.8 -24.2 -29.4 -0.3 

CO -13.4 -21.8 -22.8 -2.9 SC -2.0 -4.4 -4.7 -0.5 

HI -2.9 -2.9 -2.9 -0.8 SD -13.1 -22.7 -24.0 -1.2 

KS -17.2 -24.4 -26.9 0.3 TN -3.6 -2.8 -2.7 -0.7 

ME -13.1 -22.5 -21.9 -0.2 WV -16.2 -19.4 -25.1 -2.2 

MN -7.3 -4.7 -4.3 -0.7 WY -14.9 -24.6 -24.5 0.4 

MO -16.9 -22.6 -26.3 -0.1 Avg. -12.3 -17.2 -17.9 -0.9 

167
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIRDS Results by Building Type for the Nationwide Adoption of the LEC and ASHRAE 90.1-2007 

Designs 

Table B-14 6-Story Dormitory Summary Table for ASHRAE 90.1-2007 and 10-Year 

Study Period 

Percentage Change Percentage Change State State
 

Energy Use Energy Cost Carbon LCC
 Energy Use Energy Cost Carbon LCC 

AK -5.1 -19.9 -14.9 -2.6 MS -27.7 -32.2 -32.4 -4.5 

AL -26.5 -30.5 -32.5 -4.6 ND -9.0 -18.3 -20.2 -2.1 

AR -19.5 -25.6 -27.8 -3.2 NV -2.7 -2.6 -2.6 -0.2 

AZ -15.2 -16.7 -17.1 -2.2 OK -19.3 -25.8 -30.5 -2.9 

CO -10.6 -20.6 -21.8 -2.1 SC -5.9 -8.0 -8.2 -0.7 

HI -2.3 -2.3 -2.3 -0.4 SD -9.6 -19.8 -21.3 -2.3 

KS -14.3 -21.9 -24.7 -2.7 TN -2.1 -2.3 -2.3 -0.2 

ME -10.7 -20.4 -19.7 -3.1 WV -13.8 -17.2 -23.5 -1.9 

MN -3.6 -2.5 -2.3 -0.3 WY -10.6 -21.8 -21.7 -2.2 

MO -15.4 -21.3 -25.2 -2.3 Avg. -10.7 -16.3 -17.1 -2.0 

Table B-15 15-Story Hotel Building Summary Table for ASHRAE 90.1-2007 and 

10-Year Study Period 

Percentage Change Percentage Change State State
 

Energy Use Energy Cost Carbon LCC
 Energy Use Energy Cost Carbon LCC 

AK 2.7 -12.9 -7.7 -2.1 MS -25.0 -22.9 -22.8 -3.1 

AL -18.6 -22.4 -24.3 -3.2 ND -0.4 -10.9 -12.9 -1.6 

AR -9.1 -17.8 -21.0 -2.2 NV 6.0 6.8 6.5 0.6 

AZ -9.2 -8.9 -8.8 -1.3 OK -7.9 -16.3 -22.5 -1.8 

CO -3.4 -12.8 -13.9 -1.6 SC 7.4 5.0 4.7 0.6 

HI 2.1 2.1 2.2 0.3 SD -3.0 -12.1 -13.4 -1.8 

KS -7.0 -13.6 -15.9 -2.0 TN 5.8 6.7 6.9 0.6 

ME -5.0 -13.6 -13.0 -2.4 WV -6.7 -9.7 -15.8 -1.4 

MN 2.7 4.7 5.0 0.3 WY -4.0 -14.3 -14.2 -1.8 

MO -7.3 -12.4 -15.8 -1.6 Avg. -3.2 -8.1 -8.8 -1.2 

Table B-16 2-Story High School Summary Table for ASHRAE 90.1-2007 and 

10-Year Study Period 

Percentage Change Percentage Change State State
 

Energy Use Energy Cost Carbon LCC
 Energy Use Energy Cost Carbon LCC 

AK -2.4 -7.1 -5.3 -0.7 MS -16.8 -17.4 -17.4 -2.3 

AL -12.3 -14.4 -15.6 -1.7 ND -4.9 -8.1 -8.9 -0.4 

AR -6.4 -10.5 -12.1 -0.7 NV -3.4 -2.7 -3.0 -0.4 

AZ -10.8 -11.4 -11.6 -1.5 OK -6.0 -9.8 -13.1 -0.3 

CO -5.0 -8.8 -9.3 -1.1 SC -1.7 -2.0 -2.1 0.2 

HI -1.0 -1.0 -1.0 -0.1 SD -5.0 -8.7 -9.4 -0.9 

KS -7.1 -10.3 -11.6 -0.8 TN -3.1 -2.5 -2.3 -0.4 

ME -4.9 -8.4 -8.2 -0.8 WV -6.7 -7.9 -10.7 -1.0 

MN -3.4 -2.6 -2.4 -0.5 WY -5.2 -9.4 -9.3 -0.6 

MO -7.1 -9.4 -11.2 -0.9 Avg. -5.8 -7.7 -8.2 -0.8 

168
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIRDS Results by Building Type for the Nationwide Adoption of the LEC and ASHRAE 90.1-2007 

Designs 

Table B-17 8-Story Office Building Summary Table for ASHRAE 90.1-2007 and 

10-Year Study Period 

Percentage Change Percentage Change State State 

Energy Use Energy Cost Carbon LCC Energy Use Energy Cost Carbon LCC 

AK -6.0 -10.8 -9.5 1.1 MS -15.8 -14.5 -14.5 3.1 

AL -15.3 -15.3 -15.3 1.1 ND -10.7 -12.5 -12.8 2.5 

AR -13.8 -14.5 -14.7 -3.9 NV -3.2 -1.3 -1.8 -0.4 

AZ -8.8 -7.8 -7.6 1.4 OK -16.0 -16.9 -17.4 2.4 

CO -10.7 -10.6 -10.6 -2.6 SC -2.6 -2.1 -2.1 -0.7 

HI -1.4 -1.4 -1.4 -0.3 SD -12.4 -12.9 -12.9 0.7 

KS -16.0 -14.9 -14.6 3.0 TN -4.0 -1.8 -1.5 -0.8 

ME -12.8 -13.4 -13.3 1.7 WV -13.3 -12.8 -11.8 -2.8 

MN -5.6 -2.2 -1.9 -0.3 WY -13.7 -14.0 -14.0 2.2 

MO -16.1 -14.8 -14.1 2.4 Avg. -9.8 -9.5 -9.3 0.5 

Table B-18 16-Story Office Building Summary Table for ASHRAE 90.1-2007 and 

10-Year Study Period 

Percentage Change Percentage Change State State 

Energy Use Energy Cost Carbon LCC Energy Use Energy Cost Carbon LCC 

AK 4.0 -3.2 -1.0 -0.4 MS -14.1 -7.9 -7.6 -0.9 

AL -9.1 -9.4 -9.6 -1.3 ND 2.2 -1.8 -2.4 -0.2 

AR -3.5 -7.9 -9.4 -1.0 NV 5.8 7.0 6.7 0.8 

AZ -1.9 -0.4 0.0 0.0 OK -2.9 -7.3 -10.4 -0.6 

CO 0.3 -2.4 -2.7 -0.3 SC 5.6 3.7 3.5 0.5 

HI 3.1 3.1 3.1 0.6 SD 1.2 -1.5 -1.8 -0.2 

KS -1.0 -2.2 -2.7 -0.2 TN 6.4 6.8 6.8 0.8 

ME -2.2 -4.2 -4.1 -0.7 WV -0.8 -1.5 -2.7 -0.2 

MN 3.0 4.7 4.9 0.4 WY -0.4 -3.8 -3.7 -0.4 

MO -0.7 -1.7 -2.3 -0.1 Avg. 0.5 -0.8 -0.9 -0.1 

Table B-19 1-Story Retail Store Summary Table for ASHRAE 90.1-2007 and 

10-Year Study Period 

Percentage Change Percentage Change State State 

Energy Use Energy Cost Carbon LCC Energy Use Energy Cost Carbon LCC 

AK -8.4 -13.9 -12.1 -0.7 MS -30.5 -27.3 -27.2 -1.3 

AL -23.7 -23.6 -23.5 -1.2 ND -15.7 -18.0 -18.4 -0.3 

AR -17.5 -18.7 -19.1 -2.6 NV -10.0 -6.4 -7.4 -1.2 

AZ -19.9 -18.6 -18.3 -1.7 OK -19.1 -20.3 -21.1 1.4 

CO -17.1 -17.3 -17.3 -2.9 SC -5.9 -4.9 -4.8 -0.1 

HI -0.5 -0.5 -0.5 0.0 SD -16.1 -18.4 -18.7 -1.1 

KS -19.4 -20.2 -20.5 0.2 TN -8.4 -5.3 -4.9 -0.4 

ME -16.7 -18.5 -18.4 -0.9 WV -19.5 -19.4 -19.0 -2.6 

MN -11.7 -6.9 -6.3 -0.3 WY -16.9 -18.9 -18.9 -0.9 

MO -19.5 -19.9 -20.1 0.5 Avg. -15.2 -15.1 -15.0 -0.9 

169
 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

BIRDS Results by Building Type for the Nationwide Adoption of the LEC and ASHRAE 90.1-2007 

Designs 

Table B-20 1-Story Restaurant Summary Table for ASHRAE 90.1-2007 and 

10-Year Study Period 

Percentage Change Percentage Change State State 

Energy Use Energy Cost Carbon LCC Energy Use Energy Cost Carbon LCC 

AK -12.4 -17.0 -15.4 2.4 MS -24.8 -23.1 -23.0 3.6 

AL -21.0 -22.1 -22.6 1.5 ND -20.6 -20.8 -20.9 2.9 

AR -16.2 -19.6 -20.7 -3.1 NV -11.3 -6.7 -8.1 -1.7 

AZ -16.1 -14.6 -14.2 0.8 OK -17.3 -21.0 -23.6 4.2 

CO -18.6 -18.8 -18.8 -4.5 SC -2.8 -2.8 -2.8 -0.5 

HI -2.6 -2.6 -2.6 -0.6 SD -19.9 -20.9 -21.0 0.3 

KS -18.5 -20.1 -20.6 4.9 TN -4.4 -2.9 -2.6 -0.9 

ME -22.8 -22.8 -22.8 1.4 WV -17.2 -17.8 -18.3 -3.5 

MN -17.0 -10.1 -9.2 -2.2 WY -22.4 -22.9 -22.9 1.6 

MO -16.3 -18.2 -19.3 4.6 Avg. -15.6 -15.5 -15.6 0.4 

170