NIST Special Publication 1165

Benefits and Costs of Energy 

Standard Adoption in New 

Commercial Buildings: State-byState Summaries

Joshua Kneifel 

NIST Special Publication 1165

Benefits and Costs of Energy 

Standard Adoption in New 

Commercial Buildings: State-byState Summaries

Joshua Kneifel

Applied Economics Office 

Engineering Laboratory

September 2013

U.S. Department of Commerce 

Penny Pritzker, 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 1165

Natl. Inst. Stand. Technol. Spec. Publ. 1165, 110 pages (September 2013) 

CODEN: NSPUE2
iii

Abstract

Energy efficiency requirements in current commercial building energy codes vary across 

states. Energy standards that are currently adopted by states range from ASHRAE 

90.1-1999 to ASHRAE 90.1-2007. Some states do not have a code requirement for energy 

efficiency, leaving it up to the locality or jurisdiction to set their own requirements. The 

six National Institute of Standards and Technology (NIST) Special Publications (1147, 

1148-1, 1148-2, 1148-3, and 1148-4) use the Building Industry Reporting and Design for 

Sustainability (BIRDS) database to analyze the impacts that the adoption of newer, more 

efficient commercial building energy codes would have on building energy use, 

operational energy costs, building life-cycle costs, and energy-related carbon emissions

for each state by Census Region. This study summarizes the results from the series of 

documents for each of the 50 states into a two-page section.

Keywords

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

efficiency; commercial buildings
iv
v

Preface

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

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

summarizes the energy consumption, life-cycle cost, and energy-related carbon emissions

impacts from the adoption of new state energy codes based on more efficient building 

energy standards based on the BIRDS database for all 50 states. The intended audience is 

the National Institute of Standards and Technology, researchers in the commercial 

building sector, and any other government or private research group that is concerned 

with energy efficiency in commercial building designs.

Disclaimers

Certain trade names and company products are mentioned in the text in order to 

adequately specify the technical procedures and equipment used. In no case does such 

identification imply recommendation or endorsement by the National Institute of 

Standards and Technology, nor does it imply that the products are necessarily the best 

available for the purpose.

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.
vi
vii

Acknowledgements

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

report. They include Dr. David Butry and Dr. Robert Chapman of Engineering 

Laboratory’s (EL’s) Applied Economics Office, Mr. Matthew Boyd 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.

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
viii
ix

Table of Contents

Abstract.............................................................................................................................iii

Preface................................................................................................................................ v

Acknowledgements ......................................................................................................... vii

Author Information ........................................................................................................ vii

List of Figures................................................................................................................. xiii

List of Tables................................................................................................................... xv

List of Acronyms............................................................................................................ xix

Executive Summary....................................................................................................... xxi

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

2 Alaska......................................................................................................................... 7

2.1 Statewide Results................................................................................................. 7

2.2 Within State Variation.......................................................................................... 8

2.3 The Bottom Line .................................................................................................. 8

3 Alabama..................................................................................................................... 9

3.1 Statewide Results................................................................................................. 9

3.2 Within State Variation........................................................................................ 10

3.3 The Bottom Line ................................................................................................ 10

4 Arkansas.................................................................................................................. 11

4.1 Statewide Results............................................................................................... 11

4.2 The Bottom Line ................................................................................................ 12

5 Arizona..................................................................................................................... 13

5.1 Statewide Results............................................................................................... 13

5.2 Within State Variation........................................................................................ 14

5.3 The Bottom Line ................................................................................................ 14

6 California................................................................................................................. 15

6.1 Statewide Results............................................................................................... 15

6.2 Within State Variation........................................................................................ 16

6.3 The Bottom Line ................................................................................................ 16

7 Colorado................................................................................................................... 17

7.1 Statewide Results............................................................................................... 17

7.2 Within State Variation........................................................................................ 18

7.3 The Bottom Line ................................................................................................ 18

8 Connecticut.............................................................................................................. 19

8.1 Statewide Results............................................................................................... 19

8.2 The Bottom Line ................................................................................................ 20

9 Delaware .................................................................................................................. 21

9.1 Statewide Results............................................................................................... 21

9.2 The Bottom Line ................................................................................................ 22

10 Florida...................................................................................................................... 23

10.1Statewide Results............................................................................................... 23

10.2Within State Variation........................................................................................ 23

10.3The Bottom Line ................................................................................................ 24

11 Georgia..................................................................................................................... 25

11.1Statewide Results............................................................................................... 25
x

11.2The Bottom Line ................................................................................................ 26

12 Hawaii ...................................................................................................................... 27

12.1Statewide Results............................................................................................... 27

12.2The Bottom Line ................................................................................................ 28

13 Idaho......................................................................................................................... 29

13.1Statewide Results............................................................................................... 29

13.2The Bottom Line ................................................................................................ 30

14 Illinois....................................................................................................................... 31

14.1Statewide Results............................................................................................... 31

14.2The Bottom Line ................................................................................................ 32

15 Indiana ..................................................................................................................... 33

15.1Statewide Results............................................................................................... 33

15.2The Bottom Line ................................................................................................ 34

16 Iowa .......................................................................................................................... 35

16.1Statewide Results............................................................................................... 35

16.2The Bottom Line ................................................................................................ 36

17 Kansas...................................................................................................................... 37

17.1Statewide Results............................................................................................... 37

17.2The Bottom Line ................................................................................................ 38

18 Kentucky.................................................................................................................. 39

18.1Statewide Results............................................................................................... 39

18.2The Bottom Line ................................................................................................ 40

19 Louisiana.................................................................................................................. 41

19.1Statewide Results............................................................................................... 41

19.2The Bottom Line ................................................................................................ 42

20 Maine........................................................................................................................ 43

20.1Statewide Results............................................................................................... 43

20.2The Bottom Line ................................................................................................ 44

21 Maryland ................................................................................................................. 45

21.1Statewide Results............................................................................................... 45

21.2The Bottom Line ................................................................................................ 46

22 Massachusetts.......................................................................................................... 47

22.1Statewide Results............................................................................................... 47

22.2The Bottom Line ................................................................................................ 48

23 Michigan .................................................................................................................. 49

23.1Statewide Results............................................................................................... 49

23.2The Bottom Line ................................................................................................ 50

24 Minnesota................................................................................................................. 51

24.1Statewide Results............................................................................................... 51

24.2The Bottom Line ................................................................................................ 52

25 Mississippi................................................................................................................ 53

25.1Statewide Results............................................................................................... 53

25.2The Bottom Line ................................................................................................ 54

26 Missouri ................................................................................................................... 55
xi

26.1Statewide Results............................................................................................... 55

26.2Within State Variation........................................................................................ 56

26.3The Bottom Line ................................................................................................ 56

27 Montana................................................................................................................... 57

27.1Statewide Results............................................................................................... 57

27.2The Bottom Line ................................................................................................ 58

28 Nebraska .................................................................................................................. 59

28.1Statewide Results............................................................................................... 59

28.2The Bottom Line ................................................................................................ 60

29 Nevada...................................................................................................................... 61

29.1Statewide Results............................................................................................... 61

29.2The Bottom Line ................................................................................................ 62

30 New Hampshire....................................................................................................... 63

30.1Statewide Results............................................................................................... 63

30.2The Bottom Line ................................................................................................ 64

31 New Jersey ............................................................................................................... 65

31.1Statewide Results............................................................................................... 65

31.2The Bottom Line ................................................................................................ 66

32 New Mexico.............................................................................................................. 67

32.1Statewide Results............................................................................................... 67

32.2The Bottom Line ................................................................................................ 68

33 New York ................................................................................................................. 69

33.1Statewide Results............................................................................................... 69

33.2Within State Variation........................................................................................ 70

33.3The Bottom Line ................................................................................................ 70

34 North Carolina ........................................................................................................ 71

34.1Statewide Results............................................................................................... 71

34.2The Bottom Line ................................................................................................ 72

35 North Dakota........................................................................................................... 73

35.1Statewide Results............................................................................................... 73

35.2The Bottom Line ................................................................................................ 74

36 Ohio .......................................................................................................................... 75

36.1Statewide Results............................................................................................... 75

36.2The Bottom Line ................................................................................................ 76

37 Oklahoma................................................................................................................. 77

37.1Statewide Results............................................................................................... 77

37.2The Bottom Line ................................................................................................ 78

38 Oregon...................................................................................................................... 79

38.1Statewide Results............................................................................................... 79

38.2The Bottom Line ................................................................................................ 80

39 Pennsylvania............................................................................................................ 81

39.1Statewide Results............................................................................................... 81

39.2Within State Variation........................................................................................ 82

39.3The Bottom Line ................................................................................................ 82
xii

40 Rhode Island............................................................................................................ 83

40.1Statewide Results............................................................................................... 83

40.2The Bottom Line ................................................................................................ 84

41 South Carolina ........................................................................................................ 85

41.1Statewide Results............................................................................................... 85

41.2The Bottom Line ................................................................................................ 86

42 South Dakota ........................................................................................................... 87

42.1Statewide Results............................................................................................... 87

42.2The Bottom Line ................................................................................................ 88

43 Tennessee ................................................................................................................. 89

43.1Statewide Results............................................................................................... 89

43.2The Bottom Line ................................................................................................ 90

44 Texas......................................................................................................................... 91

44.1Statewide Results............................................................................................... 91

44.2Within State Variation........................................................................................ 92

44.3The Bottom Line ................................................................................................ 92

45 Utah .......................................................................................................................... 93

45.1Statewide Results............................................................................................... 93

45.2The Bottom Line ................................................................................................ 94

46 Vermont ................................................................................................................... 95

46.1Statewide Results............................................................................................... 95

46.2The Bottom Line ................................................................................................ 96

47 Virginia .................................................................................................................... 97

47.1Statewide Results............................................................................................... 97

47.2The Bottom Line ................................................................................................ 98

48 Washington.............................................................................................................. 99

48.1Statewide Results............................................................................................... 99

48.2The Bottom Line .............................................................................................. 100

49 West Virginia......................................................................................................... 101

49.1Statewide Results............................................................................................. 101

49.2The Bottom Line .............................................................................................. 102

50 Wisconsin............................................................................................................... 103

50.1Statewide Results............................................................................................. 103

50.2The Bottom Line .............................................................................................. 104

51 Wyoming................................................................................................................ 105

51.1Statewide Results............................................................................................. 105

51.2The Bottom Line .............................................................................................. 106

52 Limitations and Future Research........................................................................ 107

References...................................................................................................................... 109
xiii

List of Figures

Figure 1-1 Cities and ASHRAE Climate Zones................................................................... 2
xiv
xv

List of Tables

Table 1-1 Fraction of Total Floor Space with Space Heating for which Natural Gas is an 

Energy Source by Census Division ................................................................. 3

Table 1-2 Documentation of BIRDS Database Design and Analysis................................ 5

Table 2-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period..................................................................................................... 7

Table 2-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period ........ 7

Table 2-3 Average Percentage Change from Adoption of ASHRAE 90.1-2004 by City –

10 Yr Study Period .......................................................................................... 8

Table 3-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period..................................................................................................... 9

Table 3-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period ...... 10

Table 3-3 Average Percentage Change from Adoption of ASHRAE 90.1-2007 by City –

10 Yr Study Period ........................................................................................ 10

Table 4-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr

Study Period................................................................................................... 11

Table 4-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period ...... 12

Table 5-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................... 13

Table 5-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period ...... 14

Table 5-3 Average Percentage Change from Adoption of ASHRAE 90.1-2007 by City –

10 Yr Study Period ........................................................................................ 14

Table 6-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr Study 

Period............................................................................................................. 15

Table 6-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ........ 16

Table 6-3 Average Percentage Change from Adoption of the LEC design by Climate 

Zone and City – 10 Yr Study Period ............................................................. 16

Table 7-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................... 17

Table 7-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period ...... 18

Table 7-3 Average Percentage Change from Adoption of ASHRAE 90.1-2007 by City –

10 Yr Study Period ........................................................................................ 18

Table 8-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr Study 

Period............................................................................................................. 19

Table 8-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ........ 19

Table 9-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr Study 

Period............................................................................................................. 21

Table 9-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ........ 21

Table 10-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 23

Table 10-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 23

Table 10-3 Average Percentage Change from Adoption of LEC by City – 10 Yr Study 

Period............................................................................................................. 24

Table 11-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 25
xvi

Table 11-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 25

Table 12-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................... 27

Table 12-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period .... 27

Table 13-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 29

Table 13-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 29

Table 14-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 31

Table 14-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 31

Table 15-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 33

Table 15-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 33

Table 16-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 35

Table 16-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 35

Table 17-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................... 37

Table 17-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period .... 38

Table 18-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 39

Table 18-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 39

Table 19-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 41

Table 19-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 41

Table 20-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................... 43

Table 20-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period .... 44

Table 21-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 45

Table 21-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 46

Table 22-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 47

Table 22-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 47

Table 23-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 49

Table 23-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 49

Table 24-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................... 51

Table 24-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period .... 52

Table 25-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................... 53

Table 25-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period .... 53

Table 26-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................... 55

Table 26-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period .... 56
xvii

Table 26-3 Average Percentage Change from Adoption of ASHRAE 90.1-2004 by City –

10 Yr Study Period ........................................................................................ 56

Table 27-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 57

Table 27-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 57

Table 28-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 59

Table 28-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 59

Table 29-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................... 61

Table 29-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period .... 62

Table 30-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 63

Table 30-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 64

Table 31-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 65

Table 31-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 65

Table 32-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 67

Table 32-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 67

Table 33-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 69

Table 33-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 69

Table 33-3 Average Percentage Change from Adoption of the LEC design by Climate 

Zone and City – 10 Yr Study Period ............................................................. 70

Table 34-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 71

Table 34-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 72

Table 35-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................... 73

Table 35-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period .... 74

Table 36-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 75

Table 36-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 75

Table 37-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................... 77

Table 37-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period .... 77

Table 38-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 79

Table 38-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 79

Table 39-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 81

Table 39-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 81

Table 39-3 Average Percentage Change from Adoption of the LEC design by Climate 

Zone and City – 10 Yr Study Period ............................................................. 82
xviii

Table 40-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 83

Table 40-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 83

Table 41-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................... 85

Table 41-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period .... 85

Table 42-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................... 87

Table 42-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period .... 88

Table 43-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................... 89

Table 43-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period .... 89

Table 44-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 91

Table 44-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 91

Table 44-3 Average Percentage Change from Adoption of LEC by City – 10 Yr Study 

Period............................................................................................................. 92

Table 45-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 93

Table 45-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 93

Table 46-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 95

Table 46-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 95

Table 47-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 97

Table 47-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 97

Table 48-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................... 99

Table 48-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period ...... 99

Table 49-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................. 101

Table 49-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period .. 101

Table 50-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period................................................................................................. 103

Table 50-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period .... 103

Table 51-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period................................................................................................. 105

Table 51-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period .. 106
xix

List of Acronyms

Acronym Definition

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

BIRDS Building Industry Reporting and Design for Sustainability

CBECS Commercial Buildings Energy Consumption Survey

CO2e Carbon Dioxide Equivalent

EL Engineering Laboaratory

LEC Low Energy Case

NIST National Institute of Standards and Technology

PV Present Value

SP Special Publication

TN Technical Note
xx
xxi

Executive Summary

Energy efficiency requirements in current commercial building energy codes vary across 

states. Current state energy code adoptions range from American Society of Heating, 

Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 90.1-1999 to

ASHRAE 90.1-2007. 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 standards.

This report creates two-page summaries of the results from the series of National Institute 

of Standards and Technology (NIST) Special Publications (SP 1148-1, SP 1148-2, 

SP 1148-3, SP 1148-4)1 that compare current state energy code performance to the 

performance of alternative building energy standards for each state by Census Region to 

determine whether these newer energy standards are cost-effective in reducing energy 

consumption and energy-related carbon emissions. The analysis includes a “Low Energy 

Case” (LEC) building design based on the energy efficiency requirements in ASHRAE 

189.1-2009, which increases energy efficiency beyond the ASHRAE 90.1-2007 design. 

These results are based on 13 680 whole-building energy simulations covering 11

building types in 228 cities across all states in the U.S. for a 10-year study period.

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

results allow for direct comparisons across energy standards, building types, study period 

length, climate zones, and cities within each state. Results are aggregated at the state 

level to estimate the magnitude of total energy use savings, energy cost savings, 

life-cycle cost savings and energy-related carbon emissions reductions that could be 

attained by adoption of a more energy efficient state energy code. Given the assumptions 

required in this analysis for building design and volume of new construction, the results 

should be considered as orders of magnitude impacts instead of precise estimates.

 1 NIST SP 1148-1: Benefits and Costs of Energy Standard Adoption in New Commercial Buildings: 

Northeast Census Region

NIST SP 1148-2: Benefits and Costs of Energy Standard Adoption in New Commercial Buildings: 

Midwest Census Region

NIST SP 1148-3: Benefits and Costs of Energy Standard Adoption in New Commercial Buildings: South 

Census Region

NIST SP 1148-4: Benefits and Costs of Energy Standard Adoption in New Commercial Buildings: West 

Census Region
xxii
1

1 Introduction

Energy efficiency requirements in current commercial building energy codes vary across 

states. Current state energy code adoptions range from American Society of Heating, 

Refrigerating and Air-Conditioning Engineers (ASHRAE) Standard 90.1-1999 to 

ASHRAE 90.1-2007. 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 standards.

Kneifel (2010) and Kneifel (2011a) develop a framework to simultaneously analyze the 

impacts of improving energy efficiency on energy use, energy costs, life-cycle costs, and 

carbon emissions reduction through an integrated design context for new commercial 

buildings.

2 This framework was used to create the Building Industry Reporting and 

Design for Sustainability (BIRDS) database, the analysis capabilities of which were 

discussed in NIST Special Publication 1147. NIST SP 1148-1, 1148-2, 1148-3, and 

1148-4 are a series of reports that analyze the results from the BIRDS database for all 

states in each of the four U.S. Census Regions. NIST SP 1161 summarizes the key results 

from NIST SP 1147 and the NIST SP 1148 series to highlight the implications of a 

nationwide adoption of new, more efficient state commercial building energy codes.

This report condenses the results based on the BIRDS database reported in the NIST SP 

1148 series into a two-page synopsis for each state. The summary for each state reports 

the potential impacts on the state from adopting new state energy codes that increase the 

energy efficiency in new commercial and non-low-rise residential buildings across four 

metrics: energy use savings, energy cost savings, life-cycle cost savings, and energyrelated carbon emissions reductions.

For this report, current state energy codes for commercial and non-low-rise residential 

buildings (residential buildings greater than three stories) are based on different editions 

of the International Energy Conservation Code or ASHRAE Standard 90.1, which have 

requirements that vary based on a building’s characteristics and the climate zone of the 

building location as shown in Figure 1-1.

3 For this study, the prescriptive requirements of 

different ASHRAE Standard 90.1-equivalent designs are used to meet current state energy 

codes and to define the alternative building designs. States that have not yet adopted a 

state energy code are assumed to meet ASHRAE 90.1-1999 building energy efficiency 

requirements because it is assumed to represent minimum energy-related industry 

practices. A “Low Energy Case” (LEC) design based on ASHRAE 189.1-2009, which 

goes beyond ASHRAE 90.1-2007, is included as an additional building design alternative.

 2 Emissions are reported in metric tons of carbon dioxide equivalent or tCO2e. 3 Source: NIST SP 1161
2

Figure 1-1 Cities and ASHRAE Climate Zones

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.

A 10-year study period is selected because it is assumed that few building owners are 

concerned about costs realized beyond a decade into the future. It is a conservative study 

period length because the median commercial building’s lifetime is, at a minimum, 50 

years.

4 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.

This study assumes that cooling equipment is run on electricity while heating equipment 

is run on natural gas. The most significant increases in heating and cooling equipment 

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 Standard 90.1 editions. A lack of cost data for heating and 

cooling equipment led to a very conservative approach to estimating the cost of energy 

efficiency improvements for heating and cooling equipment. As a result, the additional 

costs associated with improving heating and cooling equipment energy efficiency is 

likely overestimated.

 4 Buildings Energy Data Book (2011).
3

Natural gas accounts for 71 % of energy consumed to meet heating loads in commercial 

buildings in the U.S. in 20105, and for simplicity, assumed to be the fuel source for all 

buildings and locations for the BIRDS database. The use of natural gas for heating is 

more applicable for some locations than others due to the underlying conditions in a 

region, such as heating load and availability of fuel sources. According to the 2003 

Commercial Buildings Energy Consumption Survey (CBECS) and shown in Table 1-1, 

the percentage of the floor area of heated buildings that consumes natural gas varies 

across CBECS Climate Zones and Census Divisions: 54.7 % to 77.7 % and 56.3 % to 

85.9 %, respectively. For all categories, 50 % or more of the floor area consumes natural 

gas for heating.

Table 1-1 Fraction of Total Floor Space with Space Heating for which Natural Gas 

is an Energy Source by Census Division

CBECS Climate Zone Fraction Region Division Fraction

Zone 1 (Coldest) 77.2 % Northwest New England 56.3 %

Zone 2 77.7 % Middle Atlantic 80.1 %

Zone 3 73.3 % Midwest East North Central 85.9 %

Zone 4 75.1 % West North Central 71.4 %

Zone 5 (Warmest) 54.7 % South South Atlantic 57.9 %

Source: 2003 CBECS Table 7A, Table 8A, and 

Table 9A

Note: CBECS Climate Zones are different than 

ASHRAE Climate Zones discussed in this report.

East South Central 74.5 %

West South Central 67.9 %

West Mountain 81.3 %

Pacific 76.2 %

Source: 2003 CBECS Table 10A

The changes in energy efficiency requirements across each edition of ASHRAE 90.1 and

the LEC design lead to unequal changes in energy performance across building 

components and can lead to a shift in fuel consumption from one fuel source to another 

(from electricity to natural gas and visa versa). For example, several energy efficiency 

measures adopted in the LEC design, including lower lighting power densities, 

daylighting, and overhangs, combine to reduce lighting loads while decreasing heat gains 

from both internal and external sources. As a result, electricity consumption decreases 

from lower lighting and cooling loads while increasing natural gas consumption to meet 

the larger heating load requirements.

Results are analyzed in both percentage and absolute value terms (‘Statewide Results’). 

The percentage savings results are based on a non-weighted average of the 11 building 

types, providing a relative impact of each standard edition. Additionally, where there is 

 5 Buildings Energy Data Book (2011).
4

significant variation, the percentage changes are used for comparisons across cities within 

each state (‘Within State Variation’). Variation increases with the land mass of the state, 

the number of climate zones in a state, and the number of cities within the state that have 

adopted energy codes that increase energy efficiency beyond the state energy code. The 

results for each state are summarized in the section ‘The Bottom Line.’

Results are aggregated at the state level to estimate the magnitude of total energy use 

savings, energy cost savings, present value (PV) life-cycle cost savings and 

energy-related carbon emissions (metric tons of carbon dioxide equivalent or CO2e) 

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

code. The non-weighted average savings per unit of floor area for all locations in a state 

for each of the 11 building types is multiplied by the average annual new floor area for 

that building type. The sum of the 11 building types is then divided by the fraction of the 

average total annual new building stock in the state because the eleven building types are 

assumed to be representative of the entire new building stock. Weighting the impacts by 

the amount of new construction for that building type can lead to total changes that differ 

in sign from the non-weighted average percentage changes. For example, a state could 

realize an average percentage reduction in life-cycle costs from the adoption of the LEC 

design, but realize an increase in total life-cycle costs because the building type with the 

greatest amount of new construction realizes large increases in life-cycle costs, 

overwhelming the life-cycle savings from building types for which it is cost-effective to 

adopt the LEC design.

There are a number of other assumptions made for this analysis. The building types 

selected for the BIRDS database were chosen for a number of reasons, including to show 

how the impacts of energy efficiency measures differ across a variety of buildings, 

including some less typical building designs (e.g., 100 % glazing). The new construction

floor area data that is available is at the state level, which leads to an equal weighting of 

the cities included in the database and excludes the amount that each city contributes to 

new construction. The energy performance assumes 100 % enforcement of building 

energy codes, which overestimates the overall average energy performance of both the 

baseline and alternative building designs. A 3 % discount rate was selected for the 

analysis because that is the current rate for federal energy-related projects, which may be 

low or high depending on the investors time horizon and aversion to risk.

Given the assumptions required for this analysis, the results should be considered as 

general magnitude impacts instead of precise estimates. See the corresponding documents

listed in Table 1-2 for additional information on the BIRDS database design, analysis, 

and results.
5

Table 1-2 Documentation of BIRDS Database Design and Analysis

Aspect of BIRDS Database Document(s) NIST Document #

Simulation Design Kneifel 2011b TN 1716

Life-Cycle Costing and Life-Cycle Assessment Approaches Kneifel 2012 TN 1732

Database Analysis Capabilities Kneifel 2013a SP 1147

State-Level Results by Census Region Kneifel 2013b,c,d.e SP 1147-1, -2, -3, -4

Nationwide and Across State Analysis Kneifel 2013f SP 1161

SP = Special Publication

TN = Technical Note
6
7

2 Alaska

Alaska is the most northern state in the United States, located in ASHRAE Climate 

Zone 6, Zone 7, and Zone 8. Alaska has yet to adopt a state energy code for commercial 

building construction design and, for this analysis, is assumed to build to the current 

minimum industry practices represented by ASHRAE 90.1-1999 requirements.

2.1 Statewide Results

Table 2-1 shows that, on average, adopting newer editions of ASHRAE 90.1 or the LEC 

design lead to percentage reductions in energy consumption up to 16.7 %, energy costs

up to 27.6 %, and energy-related carbon emissions up to 24.0 %. Additionally, adopting

ASHRAE 90.1-2004, ASHRAE 90.1-2007, or the LEC design leads to percentage 

reductions in life-cycle costs up to 1.0 %.

Table 2-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2001 2004 2007 LEC

Energy Use -0.2 -0.8 -4.8 -16.7

Energy Cost -0.4 -12.7 -14.3 -27.6

Carbon Emissions -0.3 -8.9 -11.1 -24.0

Life-Cycle Cost 1.5 -0.5 -0.8 -1.0

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Alaska averaged 0.3 million m

2 (3.1 million ft2

) of new floor area annually. Table 2-2

shows that based on its average new construction, the state would realize reductions in 

energy consumption in GWh, energy costs in present value dollars (PV$), energy-related 

carbon emissions in metric tCO2e, and life-cycle costs in present value dollars (PV$) 

from adopting ASHRAE 90.1-2007 or the LEC design as its state energy code over a 

10-year study period for one year’s worth of new construction. Adoption of ASHRAE 

90.1-2004 realizes an increase in energy consumption while decreasing energy costs, 

carbon emissions, and life-cycle costs.

Table 2-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2001 2004 2007 LEC

Energy Use GWh -1.1 1.9 -14.0 -99.4

Energy Cost PV$Million -$0.1 -$3.9 -$4.3 -$9.8

Carbon Emissions 1000 Metric tCO2e -1 -18 -22 -58

Life-Cycle Cost PV$Million $3. 8 -$0.8 -$1.4 -$2.4
8

2.2 Within State Variation

Alaska is unique from other states in that it is the largest state by land mass and is located 

in the coldest climate zones in the United States. As a result, the heating load varies

drastically across the state, which leads to significant variation in energy performance 

across cities within the same climate zone, particularly in the coldest climate zone 

(Zone 8). As shown in Table 2-3, buildings in Barrow realize an increase, on average, in 

energy consumption (10.8 %) from the adoption of ASHRAE 90.1-2004 while buildings 

in Fairbanks and Nome realize a decrease in energy consumption (2.5 % and 2.1 %).

Table 2-3 Average Percentage Change from Adoption of ASHRAE 90.1-2004 by 

City – 10 Yr Study Period

Cities Zone Metric

Energy Use Energy Costs Carbon Emissions Life-Cycle Costs

Barrow 8 10.8 -4.4 1.2 0.4

Fairbanks 8 -2.5 -12.2 -8.5 -0.2

Nome 8 -2.1 -12.6 -8.7 -0.5

Assuming natural gas is used for heating in Alaska, the adoption of newer editions of 

ASHRAE 90.1 lead to a shift in energy consumption from electricity to natural gas. In 

Alaska, natural gas is cheaper on a per-unit of energy basis and leads to less CO2e 

emissions per unit of energy consumed. As a result, the shift in consumption from 

electricity to natural gas leads to greater percentage savings in both energy costs and 

carbon emissions than the percentage savings in energy consumption. Table 2-3 shows 

the extreme case in Barrow, which realizes an overall increase in energy consumption of 

10.8 % from the adoption of ASHRAE 90.1-2004 while realizing a decrease in energy 

costs (-4.4 %) and smaller increase of carbon emissions (1.2 %) due to the shift in fuels.

2.3 The Bottom Line

Alaska could benefit from the adoption of a state energy code, particularly by taking an 

aggressive approach at increasing new building energy efficiency requirements. Adopting 

the LEC design, which is based on the energy efficiency requirements defined in 

ASHRAE 189.1-2009, leads to greater reductions in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs than adopting any edition of

ASHRAE 90.1. If Alaska were to adopt a state energy code similar to the majority of 

states in the U.S. (ASHRAE 90.1-2007), it could still realize savings, although much 

smaller, in energy consumption, energy costs, and energy-related carbon emission while 

decreasing life-cycle costs. These are conservative estimates because a building’s lifetime 

is significantly longer than the 10-year study period length. As the study period increases,

operating energy becomes a more significant driver of overall costs, which will drive lifecycle cost savings up.
9

3 Alabama

Alabama is located in the East South Central Census Division and spans two climate 

zones (Zone 2A and Zone 3A). The state does not have a commercial building energy 

code and, for this analysis, is assumed to build to the current minimum industry practices 

represented by ASHRAE 90.1-1999 requirements.

3.1 Statewide Results

Table 3-1 shows that, on average, adopting newer editions of ASHRAE 90.1 or the LEC 

design lead to percentage reductions in energy consumption up to 33.6 %, energy costs

up to 37.2 %, and energy-related carbon emissions up to 39.0 %. Additionally, adopting

ASHRAE 90.1-2004, ASHRAE 90.1-2007, or the LEC design leads to percentage 

reductions in life-cycle costs up to 2.5 %.

Table 3-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2001 2004 2007 LEC

Energy Use -1.8 -17.3 -19.9 -33.6

Energy Cost -1.9 -19.4 -21.9 -37.2

Carbon Emissions -2.0 -20.5 -22.9 -39.0

Life-Cycle Cost 2.0 -1.1 -1.5 -2.5

Assuming natural gas is used for heating in Alabama, the adoption of newer editions of 

ASHRAE 90.1 lead to a shift in energy consumption from electricity to natural gas. In 

Alabama, natural gas is cheaper on a per-unit of energy basis and leads to less CO2e 

emissions per unit of energy consumed. As a result, the shift in consumption from 

electricity to natural gas leads to greater percentage savings in both energy costs and 

carbon emissions than the percentage savings in energy consumption.

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Alabama averaged 2.3 million m2 (24.3 million ft2

) of new floor area annually. Table 

3-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption in GWh, energy costs in present value dollars (PV$), 

energy-related carbon emissions in metric tCO2e, and life-cycle costs in present value 

dollars (PV$) from adopting the ASHRAE 90.1-2004, ASHRAE 90.1-2007, or LEC design 

as its state energy code over a 10-year study period for one year’s worth of new 

construction.
10

Table 3-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2001 2004 2007 LEC

Energy Use GWh -48.9 -518.4 -631.6 -1050.6

Energy Cost PV$Million -$3.9 -$42.5 -$49.8 -$84.9

Carbon Emissions 1000 Metric tCO2e -41 -458 -528 -909

Life-Cycle Cost PV$Million $30.1 -$18.5 -$25.7 -$37.0

3.2 Within State Variation

Alabama is one of a few states in which one of its cities, Huntsville, has adopted a newer 

edition of ASHRAE 90.1 as its state energy code (ASHRAE 90.1-2001). As a result, the 

percentage reductions in energy use, energy costs, and carbon emission, are smaller for 

Huntsville than for the other cities in the state, even those cities located in the same 

climate zone. As shown in Table 3-3, buildings in Huntsville realize a decrease, on 

average, in energy consumption of 13.5 % from the adoption of ASHRAE 90.1-2007

while buildings in Birmingham and Montgomery realize a decrease in energy 

consumption of 17.8 % and 24.5 %, respectively.

Table 3-3 Average Percentage Change from Adoption of ASHRAE 90.1-2007 by 

City – 10 Yr Study Period

Cities Code Zone Metric

Energy Use Energy Costs Carbon Emissions Life-Cycle Costs

Mobile 1999 2 -23.9 -24.1 -23.8 -2.2

Birmingham 1999 3 -17.8 -21.5 -22.7 -1.6

Huntsville 2001 3 -13.5 -18.1 -20.1 -3.8

Montgomery 1999 3 -24.5 -23.9 -23.4 -2.4

3.3 The Bottom Line

Alabama could benefit from the adoption of a state energy code, particularly by taking an 

aggressive approach at increasing new building energy efficiency requirements. Adopting 

the LEC design, which is based on the energy efficiency requirements defined in 

ASHRAE 189.1-2009, leads to greater reductions in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs than adopting any edition of

ASHRAE 90.1. If Alabama were to adopt a state energy code similar to the majority of 

states in the U.S. (ASHRAE 90.1-2007), it could still realize savings, although much 

smaller, in energy consumption, energy costs, and energy-related carbon emission while 

decreasing life-cycle costs. These are conservative estimates because a building’s lifetime 

is significantly longer than the 10-year study period length. As the study period increases,

operating energy becomes a more significant driver of overall costs, which will drive lifecycle cost savings up.
11

4 Arkansas

Arkansas is one of two states in the South Census Region that have adopted ASHRAE 

90.1-2001 as their state energy code for commercial buildings, is located in the West 

South Central Census Division, and spans two climate zones (Zone 3A and Zone 4A).

4.1 Statewide Results

Table 4-1 shows that, on average, adopting newer editions of ASHRAE 90.1 or the LEC 

design lead to percentage reductions in energy consumption up to 27.7 %, energy costs

up to 33.9 %, and energy-related carbon emissions up to 36.1 % while decreasing 

life-cycle costs up to 3.3 %.

Table 4-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2004 2007 LEC

Energy Use -12.8 -13.9 -27.7

Energy Cost -16.5 -18.3 -33.9

Carbon Emissions -17.8 -19.9 -36.1

Life-Cycle Cost -2.4 -2.7 -3.3

Assuming natural gas is used for heating in Arkansas, the adoption of newer editions of 

ASHRAE 90.1 leads to a shift in energy consumption from electricity to natural gas. In 

Arkansas, natural gas is cheaper on a per-unit of energy basis and leads to less CO2e 

emissions per unit of energy consumed. As a result, the shift in consumption from 

electricity to natural gas leads to greater percentage savings in both energy costs and 

carbon emissions than the percentage savings in energy consumption.

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Arkansas averaged 1.2 million m

2 (12.8 million ft2

) of new floor area annually. Table 

4-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption in GWh, energy costs in present value dollars (PV$), 

energy-related carbon emissions in metric tCO2e, and life-cycle costs in present value 

dollars (PV$) from adopting the ASHRAE 90.1-2004, ASHRAE 90.1-2007, or LEC design 

as its state energy code over a 10-year study period for one year’s worth of new 

construction.
12

Table 4-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2004 2007 LEC

Energy Use GWh -173.6 -204.3 -426.1

Energy Cost PV$Million -$12.6 -$14.4 -$28.6

Carbon Emissions 1000 Metric tCO2e -168 -190 -373

Life-Cycle Cost PV$Million -$17.7 -$17.5 -$20.4

4.2 The Bottom Line

Arkansas could benefit from the adoption of a more efficient state energy code, 

particularly by taking an aggressive approach at increasing new building energy 

efficiency requirements. Adopting the LEC design, which is based on the energy 

efficiency requirements defined in ASHRAE 189.1-2009, leads to greater reductions in 

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

than adopting any edition of ASHRAE 90.1. If Arkansas were to adopt a state energy code 

similar to the majority of states in the U.S. (ASHRAE 90.1-2007), it could still realize 

savings, although much smaller, in energy consumption, energy costs, and energy-related 

carbon emission while decreasing life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
13

5 Arizona

Arizona is located in the Mountain Census Division and spans four climate zones 

(Zone 2B, Zone 3B, Zone 4B, and Zone 5B). The state does not have a commercial 

building energy code and, for this analysis, is assumed to build to the current minimum 

industry practices represented by ASHRAE 90.1-1999 requirements. However, it is 

common for cities in Arizona to adopt local energy codes for commercial buildings. 

Arizona is the only state in this study in which more than one city has adopted a local 

energy code that is two editions of ASHRAE 90.1 (-2004) beyond its assumed baseline 

standard edition. For this reason, only results for ASHRAE 90.1-2004, ASHRAE 

90.1-2007, and the LEC design are included in this analysis. The estimated impacts for 

ASHRAE 90.1-2004 are tempered since three of the six cities have already adopted that 

edition.

5.1 Statewide Results

Table 5-1 shows that, on average, adopting newer editions of ASHRAE 90.1 or LEC 

design lead to percentage reductions in energy consumption up to 28.3 %, energy costs

up to 31.2 %, and energy-related carbon emissions up to 31.9 %. Additionally, adopting

ASHRAE 90.1-2007 or the LEC design leads to percentage reductions in life-cycle costs

up to 2.1 %.

Table 5-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Arizona averaged 4.8 million m2 (51.2 million ft2

) of new floor area annually. Table 

5-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption in GWh, energy costs in present value dollars (PV$), and 

energy-related carbon emissions in metric tCO2e from adopting the ASHRAE 90.1-2004, 

ASHRAE 90.1-2007, or LEC design as its state energy code over a 10-year study period 

for one year’s worth of new construction. Additionally, the adoption of the ASHRAE 

90.1-2007 and LEC designs lead to reductions in life-cycle costs in present value dollars 

(PV$).

Metric 2004 2007 LEC

Energy Use -7.6 -12.9 -28.3

Energy Cost -9.3 -12.8 -31.2

Carbon Emissions -9.7 -12.8 -31.9

Life-Cycle Cost 0.2 -0.7 -2.1
14

Table 5-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2004 2007 LEC

Energy Use GWh -449.2 -946.3 -1857.5

Energy Cost PV$Million -$36.1 -$62.2 -$135.6

Carbon Emissions 1000 Metric tCO2e -341 -562 -1255

Life-Cycle Cost PV$Million $15.8 -$30.8 -$79.1

5.2 Within State Variation

Arizona realizes significant variation in reductions in energy use, energy costs, and 

carbon emissions because three of the six cities have adopted their own local energy 

codes based on ASHRAE 90.1-2004. As shown in Table 5-3, buildings in Phoenix, 

Tucson, and Flagstaff realize smaller reductions in energy consumption than cities 

located in the same climate zone from the adoption of ASHRAE 90.1-2007.

Table 5-3 Average Percentage Change from Adoption of ASHRAE 90.1-2007 by 

City – 10 Yr Study Period

Cities Code Zone Metric

Energy Use Energy Costs Carbon Emissions Life-Cycle Costs

Phoenix 2004 2B -8.6 -6.7 -7.1 -1.5

Tucson 2004 2B -8.7 -5.9 -6.0 -1.3

Yuma 1999 2B -24.2 -24.1 -24.1 -1.1

Prescott 1999 4B -16.1 -19.2 -19.6 0.1

Flagstaff 2004 5B -3.7 -1.8 -1.6 -0.3

Winslow 1999 5B -16.2 -19.1 -19.5 0.0

5.3 The Bottom Line

Even though the impacts vary significantly across the state, Arizona could benefit from 

the adoption of a state energy code, particularly by taking an aggressive approach at 

increasing new building energy efficiency requirements. Adopting the LEC design, which 

is based on the energy efficiency requirements defined in ASHRAE 189.1-2009, leads to 

greater reductions in energy consumption, energy costs, energy-related carbon emissions, 

and life-cycle costs than adopting any edition of ASHRAE 90.1. If Arizona were to adopt 

a state energy code similar to the majority of states in the U.S. (ASHRAE 90.1-2007), it 

could still realize savings, although much smaller, in energy consumption, energy costs, 

and energy-related carbon emission while decreasing life-cycle costs. These are 

conservative estimates because a building’s lifetime is significantly longer than the 10-

year study period length. As the study period increases, operating energy becomes a more 

significant driver of overall costs, which will drive life-cycle cost savings up.
15

6 California

California has adopted the California Building Standards Code, otherwise known as 

Title 24. California’s state energy code for commercial buildings is assumed to be 

ASHRAE 90.1-2007 for this study because it is the edition of ASHRAE 90.1 that most 

closely correlates to the requirements in Title 24. California is located in the Pacific 

Census Division, and spans five climate zones and seven subzones (Zone 2B, Zone 3B, 

Zone 3C, Zone 4B, Zone 4C, Zone 5B, and Zone 6B). Simulations are run for cities in 

Zone 3B, Zone 3C, and Zone 4B, which are the subzones that cover most of the state and 

contain the most significant population centers in California.

6.1 Statewide Results

Table 6-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (19.8 %), energy costs (24.5 %), and energy-related 

carbon emissions (22.6 %) while decreasing life-cycle costs (1.3 %). Assuming natural 

gas is used for heating in California, the adoption of the LEC design leads to a shift in 

energy consumption from electricity to natural gas. In California, natural gas is cheaper 

on a per-unit of energy basis and leads to less CO2e emissions per unit of energy 

consumed. As a result, the shift in consumption from electricity to natural gas leads to 

greater percentage savings in both energy costs and carbon emissions than the percentage

savings in energy consumption.

Table 6-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -19.8

Energy Cost -24.5

Carbon Emissions -22.6

Life-Cycle Cost -1.3

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in California averaged 14.5 million m

2 (156.0 million ft2

) of new floor area annually. 

Table 6-2 shows that based on its average new construction, the state would realize 

reductions in energy consumption (2543 GWh), energy costs ($306 million), energyrelated carbon emissions (1.4 million metric tons), and life-cycle costs ($125 million) 

from adopting the LEC design as its state energy code over a 10-year study period for one 

year’s worth of new construction.
16

Table 6-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -2543.2

Energy Cost PV$Million -$305.6

Carbon Emissions 1000 Metric tCO2e -1372

Life-Cycle Cost PV$Million -$124.9

6.2 Within State Variation

Cities considered in this study span across the state. As a result, there is variation in 

results across climate zones and across cities within climate zones in California. As 

shown in Table 6-3, buildings in Zone 3B realize the greatest average reductions in 

energy consumption (20.4 %) from the adoption of the LEC design followed by buildings 

in Zone 3C (17.5 %) and Zone 4B (14.3 %). The average reductions in energy 

consumption across cities within Zone 3B vary from 17.7 % in Sacramento to 25.1 % in 

San Diego with cities further south tending to realize greater reductions.

Table 6-3 Average Percentage Change from Adoption of the LEC design by 

Climate Zone and City – 10 Yr Study Period

Zone Cities Metric

Energy Use Energy Costs Carbon Emissions Life-Cycle Costs

3B -20.4 -24.5 -23.4 -1.5

Bakersfield -19.1 -22.8 -21.6 -1.4

Daggett -20.1 -23.0 -22.1 -1.4

Fresno -18.1 -23.0 -21.2 -1.6

Long Beach -23.8 -25.9 -25.4 -1.4

Los Angeles -24.4 -26.5 -26.0 -1.6

Riverside -20.7 -24.8 -23.4 -1.8

Sacramento -17.7 -23.4 -21.2 -1.4

San Diego -25.1 -26.3 -26.1 -1.4

3C -17.5 -25.0 -21.8 -0.6

4B -14.3 -23.9 -19.4 -1.2

6.3 The Bottom Line

California could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009.

Adoption of the LEC design would lead to reductions in total energy consumption, 

energy cost, and energy-related carbon emissions while decreasing total life-cycle costs. 

These are conservative estimates because a building’s lifetime is significantly longer than 

the 10-year study period length. As the study period increases, operating energy becomes 

a more significant driver of overall costs, which will drive life-cycle cost savings up.
17

7 Colorado

Colorado is the only state in the West Census Region that has adopted ASHRAE 

90.1-2001 as its state energy code for commercial buildings, is located in the Mountain 

Census Division, and spans four climate zones (Zone 4B, Zone 5B, Zone 6B, and 

Zone 7).

7.1 Statewide Results

Table 7-1 shows that, on average, adopting newer editions of ASHRAE 90.1 or the LEC 

design lead to percentage reductions in energy consumption up to 23.5 %, energy costs

up to 32.7 %, and energy-related carbon emissions up to 33.8 %. Additionally, adopting

ASHRAE 90.1-2004, ASHRAE 90.1-2007, or the LEC design leads to percentage 

reductions in life-cycle costs up to 2.8 %.

Table 7-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2004 2007 LEC

Energy Use -6.9 -10.4 -23.5

Energy Cost -14.1 -15.2 -32.7

Carbon Emissions -15.0 -15.8 -33.8

Life-Cycle Cost -1.9 -2.2 -2.8

Assuming natural gas is used for heating in Colorado, the adoption of newer editions of 

ASHRAE 90.1 leads to a shift in energy consumption from electricity to natural gas. In 

Colorado, natural gas is cheaper on a per-unit of energy basis and leads to less CO2e 

emissions per unit of energy consumed. As a result, the shift in consumption from 

electricity to natural gas leads to greater percentage savings in both energy costs and 

carbon emissions than the percentage savings in energy consumption.

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Colorado averaged 3.3 million m2 (35.4 million ft2

) of new floor area annually. Table 

7-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption in GWh, energy costs in present value dollars (PV$), energyrelated carbon emissions in metric tCO2e, and life-cycle costs in present value dollars 

(PV$) from adopting the ASHRAE 90.1-2004, ASHRAE 90.1-2007, or LEC design as its 

state energy code over a 10-year study period for one year’s worth of new construction.
18

Table 7-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2004 2007 LEC

Energy Use GWh -308.8 -542.9 -1112.9

Energy Cost PV$Million -$30.6 -$35.0 -$72.7

Carbon Emissions 1000 Metric tCO2e -486 -541 -1 126

Life-Cycle Cost PV$Million -$46.1 -$53.9 -$59.7

7.2 Within State Variation

One city in Colorado, Grand Junction, has adopted its own state energy code based on 

ASHRAE 90.1-2004. As a result, Grand Junction realizes smaller reductions in energy 

use, energy costs, and carbon emissions than the other three cities within Zone 5B in 

Colorado. As shown in Table 7-3, buildings in Grand Junction realize a reduction in 

energy consumption of 3.2 % from the adoption of ASHRAE 90.1-2007, which is much 

lower than the reductions for the other three cities located in the same climate zone, 

which range from 12.4 % to 13.2 %.

Table 7-3 Average Percentage Change from Adoption of ASHRAE 90.1-2007 by 

City – 10 Yr Study Period

Cities Code Zone Metric

Energy Use Energy Costs Carbon Emissions Life-Cycle Costs

Boulder 2001 5B -12.5 -17.6 -18.0 -2.4

Colorado Springs 2001 5B -12.4 -17.8 -18.1 -2.4

Grand Junction 2004 5B -3.2 -1.1 -1.3 -0.4

Pueblo 2001 5B -13.2 -17.7 -17.9 -2.6

7.3 The Bottom Line

Colorado could benefit from the adoption of a state energy code, particularly by taking an 

aggressive approach at increasing new building energy efficiency requirements. Adopting 

the LEC design, which is based on the energy efficiency requirements defined in 

ASHRAE 189.1-2009, leads to greater reductions in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs than adopting any edition of

ASHRAE 90.1. If Colorado were to adopt a state energy code similar to the majority of 

states in the U.S. (ASHRAE 90.1-2007), it could still realize savings, although much 

smaller, in energy consumption, energy costs, and energy-related carbon emission while 

decreasing life-cycle costs. These are conservative estimates because a building’s lifetime 

is significantly longer than the 10-year study period length. As the study period increases,

operating energy becomes a more significant driver of overall costs, which will drive lifecycle cost savings up.
19

8 Connecticut

Connecticut has adopted ASHRAE 90.1-2007 as its state energy code for commercial 

buildings, and is located in the New England Census Division and Climate Zone 5A.

8.1 Statewide Results

Table 8-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (13.4 %), energy costs (21.5 %), and energy-related 

carbon emissions (18.7 %), and life-cycle costs (1.6 %). Assuming natural gas is used for 

heating in Connecticut, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In Connecticut, natural gas is cheaper on a 

per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 8-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -13.4

Energy Cost -21.5

Carbon Emissions -18.7

Life-Cycle Cost -1.6

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Connecticut averaged 1.4 million m2 (15.5 million ft2

) of new floor area annually. 

Table 8-2 shows that based on its average new construction, the state would realize

reductions in energy consumption (232 GWh), energy costs ($35 million), energy-related 

carbon emissions (161 000 metric tons), and life-cycle costs ($20 million) from adopting 

the LEC design as its state energy code over a 10-year study period for one year’s worth 

of new construction.

Table 8-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -232.0

Energy Cost PV$Million -$35.1

Carbon Emissions 1000 Metric tCO2e -161

Life-Cycle Cost PV$Million -$19.7
20

8.2 The Bottom Line

Connecticut could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy cost, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
21

9 Delaware

Delaware has adopted ASHRAE 90.1-2007 as its state energy code for commercial 

buildings, and is located in the South Atlantic Census Division and Climate Zone 4A.

9.1 Statewide Results

Table 9-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (14.8 %), energy costs (18.9 %), and energy-related 

carbon emissions (19.7 %), and life-cycle costs (1.9 %). Assuming natural gas is used for 

heating in Delaware, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In Delaware, natural gas is cheaper on a 

per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 9-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -14.8

Energy Cost -18.9

Carbon Emissions -19.7

Life-Cycle Cost -1.9

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Delaware averaged 0.3 million m2 (3.7 million ft2

) of new floor area annually. Table 

9-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (60 GWh), energy costs ($6.5 million), energy-related carbon 

emissions (45 000 metric tons), and life-cycle costs ($4.5 million) from adopting the LEC 

design as its state energy code over a 10-year study period for one year’s worth of new 

construction.

Table 9-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -60.1

Energy Cost PV$Million -$6.5

Carbon Emissions 1000 Metric tCO2e -45

Life-Cycle Cost PV$Million -$4.5
22

9.2 The Bottom Line

Delaware could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy cost, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
23

10 Florida

Florida has adopted ASHRAE 90.1-2007 as its state energy code for commercial 

buildings, is located in the South Atlantic Census Division, and spans two climate zones 

(Zone 1 and Zone 2A).

10.1 Statewide Results

Table 10-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (19.8 %), energy costs (20.9 %), and energy-related 

carbon emissions (21.0 %), and life-cycle costs (1.5 %). The percentage reductions are 

nearly identical for energy use, energy costs, and carbon emissions because the warm 

climate in Florida leads to minimal natural gas consumption for heating.

Table 10-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -19.8

Energy Cost -20.9

Carbon Emissions -21.0

Life-Cycle Cost -1.5

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Florida averaged 16.5 million m

2 (178.1 million ft2

) of new floor area annually. Table 

10-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (3790 GWh), energy costs ($333 million), energy-related carbon 

emissions (3 million metric tons), and life-cycle costs ($151 million) from adopting the 

LEC design as its state energy code over a 10-year study period for one year’s worth of 

new construction.

Table 10-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -3790.5

Energy Cost PV$Million -$333.0

Carbon Emissions 1000 Metric tCO2e -3 230

Life-Cycle Cost PV$Million -$151.3

10.2 Within State Variation

Florida is a large state in terms of land mass and spans two climate zones. As a result, 

there is variation across cities in the reductions in energy use, energy costs, and carbon 

emissions. As shown in Table 10-3, buildings in Zone 1 realize a greater decrease, on 
24

average, in energy consumption of 21.3 % from the adoption of the LEC design while 

buildings in Zone 2 realize a decrease in energy consumption of 19.2 % with the cities

that are further north realizing the smaller reductions.

Table 10-3 Average Percentage Change from Adoption of LEC by City – 10 Yr 

Study Period

Cities Zone Metric

Energy Use Energy Costs Carbon Emissions Life-Cycle Costs

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

10.3 The Bottom Line

Even though the impacts vary across the state, Florida could benefit from the adoption of 

the LEC design as it’s a state energy code. Adopting the LEC design, which is based on 

the energy efficiency requirements defined in ASHRAE 189.1-2009, leads to reductions in 

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

These are conservative estimates because a building’s lifetime is significantly longer than 

the 10-year study period length. As the study period increases, operating energy becomes 

a more significant driver of overall costs, which will drive life-cycle cost savings up.
25

11 Georgia

Georgia has adopted ASHRAE 90.1-2007 as its state energy code, is located in the South 

Atlantic Census Division, and spans two climate zones (Zone 2A and Zone 3A).

11.1 Statewide Results

Table 11-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (17.3 %), energy costs (20.2 %), and energy-related 

carbon emissions (21.2 %), and life-cycle costs (0.8 %). Assuming natural gas is used for 

heating in Georgia, the adoption of the LEC design leads to a shift in energy consumption 

from electricity to natural gas. In Georgia, natural gas is cheaper on a per-unit of energy 

basis and leads to less CO2e emissions per unit of energy consumed. As a result, the shift 

in consumption from electricity to natural gas leads to greater percentage savings in both 

energy costs and carbon emissions than the percentage savings in energy consumption.

Table 11-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -17.3

Energy Cost -20.2

Carbon Emissions -21.2

Life-Cycle Cost -0.8

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Georgia averaged 7.2 million m

2 (77.9 million ft2

) of new floor area annually. Table 

11-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (4603 GWh), energy costs ($103 million), energy-related carbon 

emissions (1.3 million metric tons), and life-cycle costs ($28.5 million) from adopting the 

LEC design as its state energy code over a 10-year study period for one year’s worth of 

new construction.

Table 11-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -4602.7

Energy Cost PV$Million -$102.5

Carbon Emissions 1000 Metric tCO2e -1250

Life-Cycle Cost PV$Million -$28.5
26

11.2 The Bottom Line

Georgia could benefit from the adoption of the LEC design as it’s a state energy code, 

Adopting the LEC design, which is based on the energy efficiency requirements defined 

in ASHRAE 189.1-2009, leads to reductions in energy consumption, energy cost, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
27

12 Hawaii

Hawaii is one of two states in the West Census Region that have adopted ASHRAE 

90.1-2004 as their state energy code for commercial buildings, is located in the Pacific 

Census Division, and is the only state solely located in the warmest climate zone 

(Zone 1).

12.1 Statewide Results

Table 12-1 shows that, on average, adopting ASHRAE 90.1-2007 or the LEC design lead 

to percentage reductions in energy consumption, energy costs, energy-related carbon 

emissions, and life-cycle costs with the LEC design leading to much greater percentage 

reductions. The percentage reductions are the same for energy use, energy costs, and 

carbon emissions because there is no natural gas consumption for heating; all energy use 

is from electricity consumption.

Table 12-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2007 LEC

Energy Use -1.1 -23.1

Energy Cost -1.1 -23.1

Carbon Emissions -1.1 -23.1

Life-Cycle Cost -0.2 -3.1

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Hawaii averaged 0.5 million m

2 (5.8 million ft2

) of new floor area annually. Table 12-2

shows that based on its average new construction, the state would realize reductions in 

energy consumption in GWh, energy costs in present value dollars (PV$), energy-related 

carbon emissions in metric tCO2e, and life-cycle costs in present value dollars (PV$)

from adopting the ASHRAE 90.1-2007 or LEC design as its state energy code over a 10-

year study period for one year’s worth of new construction.

Table 12-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2007 LEC

Energy Use GWh -12.1 -138.4

Energy Cost PV$Million -$2.1 -$23.9

Carbon Emissions 1000 Metric tCO2e -11 -124

Life-Cycle Cost PV$Million -$2.0 -$13.9
28

12.2 The Bottom Line

Hawaii could benefit from the adoption of a state energy code, particularly by taking an 

aggressive approach at increasing new building energy efficiency requirements. Adopting 

the LEC design, which is based on the energy efficiency requirements defined in 

ASHRAE 189.1-2009, leads to greater reductions in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs than adopting ASHRAE 90.1-2007. 

If Hawaii were to adopt a state energy code similar to the majority of states in the U.S.

(ASHRAE 90.1-2007), it could still realize savings, although much smaller, in energy 

consumption, energy costs, and energy-related carbon emission while decreasing 

life-cycle costs. These are conservative estimates because a building’s lifetime is 

significantly longer than the 10-year study period length. As the study period increases,

operating energy becomes a more significant driver of overall costs, which will drive lifecycle cost savings up.
29

13 Idaho

Idaho has adopted ASHRAE 90.1-2007 as its state energy code for commercial buildings, 

is located in the Mountain Census Division, and spans two climate zones (Zone 5B and 

Zone 6B).

13.1 Statewide Results

Table 13-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (14.3 %), energy costs (18.0 %), and energy-related 

carbon emissions (18.1 %), and life-cycle costs (0.4 %). Assuming natural gas is used for 

heating in Idaho, the adoption of the LEC design leads to a shift in energy consumption 

from electricity to natural gas. In Idaho, natural gas is cheaper on a per-unit of energy 

basis and leads to less CO2e emissions per unit of energy consumed. As a result, the shift 

in consumption from electricity to natural gas leads to greater percentage savings in both 

energy costs and carbon emissions than the percentage savings in energy consumption.

Table 13-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -14.3

Energy Cost -18.0

Carbon Emissions -18.1

Life-Cycle Cost -0.4

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Idaho averaged 0.8 million m2 (8.6 million ft2

) of new floor area annually. Table 13-2

shows that based on its average new construction, the state would realize reductions in 

energy consumption (140 GWh), energy costs ($7.6 million), energy-related carbon 

emissions (70 000 metric tons), and life-cycle costs ($1.5 million) from adopting the LEC 

design as its state energy code over a 10-year study period for one year’s worth of new 

construction.

Table 13-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -139.9

Energy Cost PV$Million -$7.6

Carbon Emissions 1000 Metric tCO2e -70

Life-Cycle Cost PV$Million -$1.5
30

13.2 The Bottom Line

Idaho could benefit from the adoption of the LEC design as its state energy code, which 

is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. Adoption 

of the LEC design leads to reduction in energy consumption, energy cost, energy-related 

carbon emissions, and life-cycle costs. These are conservative estimates because a 

building’s lifetime is significantly longer than the 10-year study period length. As the 

study period increases, operating energy becomes a more significant driver of overall 

costs, which will drive life-cycle cost savings up.
31

14 Illinois

Illinois has adopted ASHRAE 90.1-2007 as its state energy code for commercial 

buildings, is located in the East North Central Census Division, and spans two climate 

zones (Zone 4A and Zone 5A).

14.1 Statewide Results

Table 14-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (13.1 %), energy costs (20.3 %), and energy-related 

carbon emissions (20.3 %), and life-cycle costs (0.9 %). Assuming natural gas is used for 

heating in Illinois, the adoption of the LEC design leads to a shift in energy consumption 

from electricity to natural gas. In Illinois, natural gas is cheaper on a per-unit of energy 

basis and leads to less CO2e emissions per unit of energy consumed. As a result, the shift 

in consumption from electricity to natural gas leads to greater percentage savings in both 

energy costs and carbon emissions than the percentage savings in energy consumption.

Table 14-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -13.1

Energy Cost -20.3

Carbon Emissions -20.3

Life-Cycle Cost -0.9

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Illinois averaged 6.9 million m2 (74.6 million ft2

) of new floor area annually. Table 

14-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (1213 GWh), energy costs ($124 million), energy-related carbon 

emissions (1.3 million metric tons), and life-cycle costs ($31 million) from adopting the 

LEC design as its state energy code over a 10-year study period for one year’s worth of 

new construction.

Table 14-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -1212.7

Energy Cost PV$Million -$124.4

Carbon Emissions 1000 Metric tCO2e -1343

Life-Cycle Cost PV$Million -$31.4
32

14.2 The Bottom Line

Illinois could benefit from the adoption of the LEC design as its state energy code, which 

is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. Adoption 

of the LEC design leads to reduction in energy consumption, energy cost, energy-related 

carbon emissions, and life-cycle costs. These are conservative estimates because a 

building’s lifetime is significantly longer than the 10-year study period length. As the 

study period increases, operating energy becomes a more significant driver of overall 

costs, which will drive life-cycle cost savings up.
33

15 Indiana

Indiana has adopted ASHRAE 90.1-2007 as its state energy code, is located in the East 

North Central Census Division, and spans two climate zones (Zone 4A and Zone 5A).

15.1 Statewide Results

Table 15-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (13.9 %), energy costs (19.5 %), and energy-related 

carbon emissions (20.5 %), and life-cycle costs (0.6 %). Assuming natural gas is used for 

heating in Indiana, the adoption of the LEC design leads to a shift in energy consumption 

from electricity to natural gas. In Indiana, natural gas is cheaper on a per-unit of energy 

basis and leads to less CO2e emissions per unit of energy consumed. As a result, the shift 

in consumption from electricity to natural gas leads to greater percentage savings in both 

energy costs and carbon emissions than the percentage savings in energy consumption.

Table 15-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -13.9

Energy Cost -19.5

Carbon Emissions -20.5

Life-Cycle Cost -0.6

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Indiana averaged 3.7 million m

2 (39.4 million ft2

) of new floor area annually. Table 

15-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (657 GWh), energy costs ($50 million), energy-related carbon 

emissions (653 000 metric tons), and life-cycle costs ($13.3 million) from adopting the 

LEC design as its state energy code over a 10-year study period for one year’s worth of 

new construction.

Table 15-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -656.9

Energy Cost PV$Million -$49.8

Carbon Emissions 1000 Metric tCO2e -653

Life-Cycle Cost PV$Million -$13.3
34

15.2 The Bottom Line

Indiana could benefit from the adoption of the LEC design as its state energy code, which 

is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. Adoption 

of the LEC design leads to reduction in energy consumption, energy costs, energy-related 

carbon emissions, and life-cycle costs. These are conservative estimates because a 

building’s lifetime is significantly longer than the 10-year study period length. As the 

study period increases, operating energy becomes a more significant driver of overall 

costs, which will drive life-cycle cost savings up.
35

16 Iowa

Iowa has adopted ASHRAE 90.1-2007 as its state energy code, is located in the West 

North Central Census Division, and spans two climate zones (Zone 5A and Zone 6A).

16.1 Statewide Results

Table 16-1 shows that, on average, adopting the LEC design leads to percentage

reductions in energy consumption (13.2 %), energy costs (18.2 %), and energy-related 

carbon emissions (19.0 %), and life-cycle costs (0.5 %). Assuming natural gas is used for 

heating in Iowa, the adoption of the LEC design leads to a shift in energy consumption 

from electricity to natural gas. In Iowa, natural gas is cheaper on a per-unit of energy 

basis and leads to less CO2e emissions per unit of energy consumed. As a result, the shift 

in consumption from electricity to natural gas leads to greater percentage savings in both 

energy costs and carbon emissions than the percentage savings in energy consumption.

Table 16-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -13.2

Energy Cost -18.2

Carbon Emissions -19.0

Life-Cycle Cost -0.5

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Iowa averaged 1.4 million m

2 (15.6 million ft2

) of new floor area annually. Table 16-2

shows that based on its average new construction, the state would realize reductions in 

energy consumption (284 GWh), energy costs ($17.6 million), energy-related carbon 

emissions (256 000 metric tons), and life-cycle costs ($4.0 million) from adopting the 

LEC design as its state energy code over a 10-year study period for one year’s worth of 

new construction.

Table 16-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -283.7

Energy Cost PV$Million -$17.6

Carbon Emissions 1000 Metric tCO2e -256

Life-Cycle Cost PV$Million -$4.0
36

16.2 The Bottom Line

Iowa could benefit from the adoption of the LEC design as its state energy code, which is 

based on the energy efficiency requirements defined in ASHRAE 189.1-2009. Adoption 

of the LEC design leads to reduction in energy consumption, energy costs, energy-related 

carbon emissions, and life-cycle costs. These are conservative estimates because a 

building’s lifetime is significantly longer than the 10-year study period length. As the 

study period increases, operating energy becomes a more significant driver of overall 

costs, which will drive life-cycle cost savings up.
37

17 Kansas

Kansas is located in the West North Central Census Division and spans two climate zones 

(Zone 4A and Zone 5A). The state does not have a commercial building energy code and, 

for this analysis, is assumed to build to the current minimum industry practices 

represented by ASHRAE 90.1-1999 requirements.

17.1 Statewide Results

Table 17-1 shows that, on average, adopting newer editions of ASHRAE 90.1 or the LEC 

design lead to percentage reductions in energy consumption up to 26.3 %, energy costs

up to 33.5 %, and energy-related carbon emissions up to 36.1 %. However, only adopting 

the LEC design leads to percentage reductions in life-cycle costs.

Table 17-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2001 2004 2007 LEC

Energy Use -1.5 -10.3 -13.3 -26.3

Energy Cost -1.7 -15.8 -17.1 -33.5

Carbon Emissions -1.8 -17.8 -18.4 -36.1

Life-Cycle Cost 2.7 0.5 0.1 -0.7

Assuming natural gas is used for heating in Kansas, the adoption of the LEC design leads 

to a shift in energy consumption from electricity to natural gas. In Kansas, natural gas is 

cheaper on a per-unit of energy basis and leads to less CO2e emissions per unit of energy 

consumed. As a result, the shift in consumption from electricity to natural gas leads to 

greater percentage savings in both energy costs and carbon emissions than the percentage 

savings in energy consumption.

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Kansas averaged 1.1 million m

2 (11.6 million ft2

) of new floor area annually. Table 

17-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption in GWh, energy costs in present value dollars (PV$), and 

energy-related carbon emissions in metric tCO2efrom adopting the ASHRAE 90.1-2001, 

ASHRAE 90.1-2004, ASHRAE 90.1-2007, or LEC design as its state energy code over a 

10-year study period for one year’s worth of new construction. Adoption of each of the 

new editions of ASHRAE 90.1 increase life-cycle costs while adopting the LEC design 

decreases life-cycle costs.
38

Table 17-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2001 2004 2007 LEC

Energy Use GWh -23.4 -145.7 -229.5 -438.6

Energy Cost PV$Million -$1.5 -$11.7 -$13.9 -$28.6

Carbon Emissions 1000 Metric tCO2e -23 -188 -208 -436

Life-Cycle Cost PV$Million $22.3 $6.9 $2.9 -$2.3

17.2 The Bottom Line

Kansas could benefit from the adoption of a state energy code, particularly by taking an 

aggressive approach at increasing new building energy efficiency requirements. Adopting 

the LEC design, which is based on the energy efficiency requirements defined in 

ASHRAE 189.1-2009, leads to greater energy consumption, energy cost, and 

energy-related carbon emissions than adopting any edition of ASHRAE 90.1 while 

decreasing life-cycle costs. The additional energy efficiency measures adopted by the 

LEC design lead to enough energy cost savings to offset the associated energy efficiency 

investment costs. If Kansas were to adopt a state energy code similar to the majority of 

states in the U.S. (ASHRAE 90.1-2007), it could still realize savings, although much 

smaller, in energy consumption, energy costs, and energy-related carbon emission, but 

life-cycle costs would increase because there is not enough energy cost savings to offset 

the energy efficiency investment costs. These are conservative estimates because a 

building’s lifetime is significantly longer than the 10-year study period length. As the 

study period increases, operating energy becomes a more significant driver of overall 

costs, which will drive life-cycle cost savings up. As a result, the adoption of ASHRAE 

90.1-2007 may become cost-effective as the investment time horizon is extended further 

into the future.
39

18 Kentucky

Kentucky has adopted ASHRAE 90.1-2007 as its state energy code, and is located in the 

East South Central Census Division and Climate Zone 4A.

18.1 Statewide Results

Table 18-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (15.5 %), energy costs (19.3 %), and energy-related 

carbon emissions (21.3 %), and life-cycle costs (0.8 %). Assuming natural gas is used for 

heating in Kentucky, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In Kentucky, natural gas is cheaper on a 

per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 18-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -15.5

Energy Cost -19.3

Carbon Emissions -21.3

Life-Cycle Cost -0.8

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Kentucky averaged 2.0 million m2 (21.0 million ft2

) of new floor area annually. Table 

18-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (378 GWh), energy costs ($25 million), energy-related carbon 

emissions (341 000 metric tons), and life-cycle costs ($10 million) from adopting the 

LEC design as its state energy code over a 10-year study period for one year’s worth of 

new construction.

Table 18-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -378.0

Energy Cost PV$Million -$24.6

Carbon Emissions 1000 Metric tCO2e -341

Life-Cycle Cost PV$Million -$9.8
40

18.2 The Bottom Line

Kentucky could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
41

19 Louisiana

Louisiana has adopted ASHRAE 90.1-2007 as its state energy code for commercial 

buildings, is located in the West South Central Census Division, and spans two climate 

zones (Zone 2A and Zone 3A).

19.1 Statewide Results

Table 19-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (17.9 %), energy costs (20.0 %), and energy-related 

carbon emissions (20.7 %), and life-cycle costs (0.6 %). Assuming natural gas is used for 

heating in Louisiana, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In Louisiana, natural gas is cheaper on a 

per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 19-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -17.9

Energy Cost -20.0

Carbon Emissions -20.7

Life-Cycle Cost -0.6

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Louisiana averaged 1.7 million m

2 (18.3 million ft2

) of new floor area annually. Table 

19-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (325 GWh), energy costs ($21 million), energy-related carbon 

emissions (270 000 metric tons), and life-cycle costs ($3 million) from adopting the LEC 

design as its state energy code over a 10-year study period for one year’s worth of new 

construction.

Table 19-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -324.6

Energy Cost PV$Million -$20.8

Carbon Emissions 1000 Metric tCO2e -270

Life-Cycle Cost PV$Million -$3.2
42

19.2 The Bottom Line

Louisiana could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
43

20 Maine

Maine is located in the coldest climate zones in the contiguous U.S. (Zone 6 and Zone 7). 

The state does not have a commercial building energy code and, for this analysis, is 

assumed to build to the current minimum industry practices represented by ASHRAE 

90.1-1999 requirements.

20.1 Statewide Results

Table 20-1 shows that, on average, adopting newer editions of ASHRAE 90.1 or the LEC 

design lead to percentage reductions in energy consumption up to 23.1 %, energy costs

up to 29.9 %, and energy-related carbon emissions up to 29.4 %. Additionally, adopting

ASHRAE 90.1-2004, ASHRAE 90.1-2007, or the LEC design leads to percentage 

reductions in life-cycle costs.

Table 20-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2001 2004 2007 LEC

Energy Use -0.7 -6.2 -11.4 -23.1

Energy Cost -1.0 -13.8 -16.4 -29.9

Carbon Emissions -0.9 -13.3 -16.0 -29.4

Life-Cycle Cost 2.1 -0.2 -0.8 -1.7

Assuming natural gas is used for heating in Maine, the adoption of newer editions of 

ASHRAE 90.1 leads to a shift in energy consumption from electricity to natural gas. In 

Maine, natural gas is cheaper on a per-unit of energy basis and leads to less CO2e 

emissions per unit of energy consumed. As a result, the shift in consumption from 

electricity to natural gas leads to greater percentage savings in both energy costs and 

carbon emissions than the percentage savings in energy consumption.

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Maine averaged 0.5 million m2 (5.3 million ft2

) of new floor area annually. Table 20-2

shows that based on its average new construction, the state would realize reductions in 

energy consumption in GWh, energy costs in present value dollars (PV$), energy-related 

carbon emissions in metric tCO2e, and life-cycle costs in present value dollars (PV$)

from adopting the ASHRAE 90.1-2004, ASHRAE 90.1-2007, or LEC design as its state 

energy code over a 10-year study period for one year’s worth of new construction.
44

Table 20-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2001 2004 2007 LEC

Energy Use GWh -5.6 -47.0 -105.5 -216.6

Energy Cost PV$Million -$0.5 -$7.3 -$9.4 -$18.0

Carbon Emissions 1000 Metric tCO2e -3 -45 -59 -113

Life-Cycle Cost PV$Million $7.9 -$1.3 -$3.3 -$6.4

20.2 The Bottom Line

Maine could benefit from the adoption of a state energy code, particularly by taking an 

aggressive approach at increasing new building energy efficiency requirements. Adopting 

the LEC design, which is based on the energy efficiency requirements defined in 

ASHRAE 189.1-2009, leads to greater energy consumption, energy cost, energy-related 

carbon emissions, and life-cycle costs than adopting any edition of ASHRAE 90.1. The 

additional energy efficiency measures adopted by the LEC design lead to enough energy 

cost savings to offset the associated energy efficiency investment costs. If Maine were to 

adopt a state energy code similar to the majority of states in the U.S. (ASHRAE 

90.1-2007), it could still realize savings, although much smaller, in energy consumption, 

energy costs, and energy-related carbon emission while decreasing life-cycle costs. These 

are conservative estimates because a building’s lifetime is significantly longer than the 

10-year study period length. As the study period increases, operating energy becomes a 

more significant driver of overall costs, which will drive life-cycle cost savings up.
45

21 Maryland

Maryland is located in the South Atlantic Census Division and primarily in Climate 

Zone 4A, with the northwestern portion of the state located in Zone 5A. Only one city, 

Baltimore, is simulated for this study and is located in Zone 4A. While Maryland is now 

the first state to adopt ASHRAE 90.1-2010, at the time of this study the state had adopted 

ASHRAE 90.1-2007 as its state energy code for commercial buildings.

21.1 Statewide Results

Table 21-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (15.1 %), energy costs (20.6 %), and energy-related 

carbon emissions (20.0 %), and life-cycle costs (1.6 %). Assuming natural gas is used for 

heating in Maryland, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In Maryland, natural gas is cheaper on a 

per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 21-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -15.1

Energy Cost -20.6

Carbon Emissions -20.0

Life-Cycle Cost -1.6

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Maryland averaged 3.4 million m

2 (36.4 million ft2

) of new floor area annually. Table 

21-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (622 GWh), energy costs ($62 million), energy-related carbon 

emissions (449 000 metric tons), and life-cycle costs ($29 million) from adopting the 

LEC design as its state energy code over a 10-year study period for one year’s worth of 

new construction.
46

Table 21-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -622.2

Energy Cost PV$Million -$62.4

Carbon Emissions 1000 Metric tCO2e -449

Life-Cycle Cost PV$Million -$28.8

21.2 The Bottom Line

Maryland could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
47

22 Massachusetts

Massachusetts has adopted ASHRAE 90.1-2007 as its state energy code, and is located in 

the New England Census Division and Climate Zone 5A.

22.1 Statewide Results

Table 22-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (12.9 %), energy costs (20.0 %), and energy-related 

carbon emissions (18.3 %), and life-cycle costs (1.1 %). Assuming natural gas is used for 

heating in Massachusetts, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In Massachusetts, natural gas is cheaper on a 

per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 22-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -12.9

Energy Cost -20.0

Carbon Emissions -18.3

Life-Cycle Cost -1.1

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Massachusetts averaged 2.6 million m2 (27.8 million ft2

) of new floor area annually. 

Table 22-2 shows that based on its average new construction, the state would realize 

reductions in energy consumption (404 GWh), energy costs ($56 million), energy-related 

carbon emissions (277 000 metric tons), and life-cycle costs ($13 million) from adopting 

the LEC design as its state energy code over a 10-year study period for one year’s worth 

of new construction.

Table 22-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -403.8

Energy Cost PV$Million -$56.0

Carbon Emissions 1000 Metric tCO2e -277

Life-Cycle Cost PV$Million -$12.8
48

22.2 The Bottom Line

Massachusetts could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
49

23 Michigan

Michigan is located in the East North Central Census Division and has adopted ASHRAE 

90.1-2007 as its state energy code for commercial buildings. Michigan spans three 

climate zones with the southern portion of the state located in Zone 5A, the central 

portion in Zone 6A, and the northern portion in Zone 7.

23.1 Statewide Results

Table 23-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (12.0 %), energy costs (17.9 %), and energy-related 

carbon emissions (18.7 %), and life-cycle costs (0.8 %). Assuming natural gas is used for 

heating in Michigan, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In Michigan, natural gas is cheaper on a 

per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 23-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -12.0

Energy Cost -17.9

Carbon Emissions -18.7

Life-Cycle Cost -0.8

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Michigan averaged 3.0 million m

2 (31.9 million ft2

) of new floor area annually. Table 

23-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (512 GWh), energy costs ($40 million), energy-related carbon 

emissions (491 000 metric tons), and life-cycle costs ($17 million) from adopting the 

LEC design as its state energy code over a 10-year study period for one year’s worth of 

new construction.

Table 23-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -511.9

Energy Cost PV$Million -$40.4

Carbon Emissions 1000 Metric tCO2e -491

Life-Cycle Cost PV$Million -$17.0
50

23.2 The Bottom Line

Michigan could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
51

24 Minnesota

Minnesota is located in the West North Central Census Division, and spans two climate 

zones with the southern portion of the state located in Zone 6A and the northern portion 

in Zone 7. Minnesota is the only state in the Midwest Census Region that has adopted 

ASHRAE 90.1-2004 as its state energy code for commercial buildings.

24.1 Statewide Results

Table 24-1 shows that, on average, adopting ASHRAE 90.1-2007 or the LEC design leads

to percentage reductions in energy consumption, energy costs, energy-related carbon 

emissions, and life-cycle costs with the LEC design leading to much greater percentage 

reductions. 

Table 24-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2007 LEC

Energy Use -5.6 -17.7

Energy Cost -2.8 -18.5

Carbon Emissions -2.4 -18.6

Life-Cycle Cost -0.4 -0.8

Assuming natural gas is used for heating in Minnesota, the adoption of ASHRAE 

90.1-2007 leads to a shift in energy consumption from natural gas to electricity. In 

Minnesota, natural gas is cheaper on a per-unit of energy basis and leads to less CO2e 

emissions per unit of energy consumed. As a result the shift in consumption from natural 

gas to electricity leads to smaller percentage savings in both energy costs and carbon 

emissions than the percentage savings in energy consumption. The opposite occurs for 

the adoption of the LEC design, where there is a shift from electricity to natural gas and 

the percentage reduction is greater for energy costs and carbon emissions relative to 

energy consumption.

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Minnesota averaged 2.3 million m2 (25.1 million ft2

) of new floor area annually. Table 

24-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption in GWh, energy costs in present value dollars (PV$), 

energy-related carbon emissions in metric tCO2e, and life-cycle costs in present value 

dollars (PV$) from adopting the ASHRAE 90.1-2007 or LEC design as its state energy 

code over a 10-year study period for one year’s worth of new construction.
52

Table 24-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2007 LEC

Energy Use GWh -282.7 -816.7

Energy Cost PV$Million -$6.0 -$33.5

Carbon Emissions 1000 Metric tCO2e -71 -444

Life-Cycle Cost PV$Million -$7.3 -$12.4

24.2 The Bottom Line

Minnesota could benefit from the adoption of a state energy code, particularly by taking 

an aggressive approach at increasing new building energy efficiency requirements. 

Adopting the LEC design, which is based on the energy efficiency requirements defined 

in ASHRAE 189.1-2009, leads to greater reductions in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs than adopting ASHRAE 90.1-2007. 

If Minnesota were to adopt a state energy code similar to the majority of states in the U.S. 

(ASHRAE 90.1-2007), it could still realize savings, although much smaller, in energy 

consumption, energy costs, and energy-related carbon emission while decreasing 

life-cycle costs. These are conservative estimates because a building’s lifetime is 

significantly longer than the 10-year study period length. As the study period increases, 

operating energy becomes a more significant driver of overall costs, which will drive 

life-cycle cost savings up.
53

25 Mississippi

Mississippi is located in the East South Central Census Division and primarily in Climate 

Zone 3A with the southern (Gulf Coast) counties of the state located in Zone 2A. All 

cities simulated for this study are located in Zone 3A. The state does not have a 

commercial building energy code and, for this analysis, is assumed to build to the current 

minimum industry practices represented by ASHRAE 90.1-1999 requirements.

25.1 Statewide Results

Table 25-1 shows that, on average, adopting newer editions of ASHRAE 90.1 or the LEC 

design lead to percentage reductions in energy consumption up to 36.2 %, energy costs

up to 38.9 %, and energy-related carbon emissions up to 39.0 %. Additionally, adopting

ASHRAE 90.1-2004, ASHRAE 90.1-2007, or the LEC design leads to percentage 

reductions in life-cycle costs up to 1.9 %.

Table 25-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2001 2004 2007 LEC

Energy Use -2.2 -18.4 -23.7 -36.2

Energy Cost -2.4 -20.0 -23.4 -38.9

Carbon Emissions -2.4 -20.1 -23.4 -39.0

Life-Cycle Cost 2.6 -0.4 -1.1 -1.9

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Mississippi averaged 1.3 million m

2 (13.5 million ft2

) of new floor area annually. 

Table 25-2 shows that based on its average new construction, the state would realize 

reductions in energy consumption in GWh, energy costs in present value dollars (PV$), 

energy-related carbon emissions in metric tCO2e, and life-cycle costs in present value 

dollars (PV$) from adopting the ASHRAE 90.1-2004, ASHRAE 90.1-2007, or LEC design 

as its state energy code over a 10-year study period for one year’s worth of new 

construction.

Table 25-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2001 2004 2007 LEC

Energy Use GWh -34.3 -336.8 -470.6 -689.6

Energy Cost PV$Million -$2.6 -$22.6 -$28.1 -$46.3

Carbon Emissions 1000 Metric tCO2e -26 -227 -281 -465

Life-Cycle Cost PV$Million $21.4 -$5.3 -$12.3 -$14.8
54

25.2 The Bottom Line

Mississippi could benefit from the adoption of a state energy code, particularly by taking 

an aggressive approach at increasing new building energy efficiency requirements. 

Adopting the LEC design, which is based on the energy efficiency requirements defined 

in ASHRAE 189.1-2009, leads to greater reductions in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs than adopting any edition of 

ASHRAE 90.1. The additional energy efficiency measures adopted by the LEC design 

lead to enough energy cost savings to offset the associated energy efficiency investment 

costs. If Mississippi were to adopt a state energy code similar to the majority of states in 

the U.S. (ASHRAE 90.1-2007), it could still realize savings, although much smaller, in 

energy consumption, energy costs, and energy-related carbon emission while decreasing 

life-cycle costs. These are conservative estimates because a building’s lifetime is 

significantly longer than the 10-year study period length. As the study period increases,

operating energy becomes a more significant driver of overall costs, which will drive lifecycle cost savings up.
55

26 Missouri

Missouri is located in the West North Central Census Division, and spans two climate 

zones (Zone 4 and Zone 5). The state does not have a commercial building energy code 

and, for this analysis, is assumed to build to the current minimum industry practices 

represented by ASHRAE 90.1-1999 requirements.

26.1 Statewide Results

Table 26-1 shows that, on average, adopting newer editions of ASHRAE 90.1 or the LEC 

design lead to percentage reductions in energy consumption up to 26.4 %, energy costs up 

to 31.9 %, and energy-related carbon emissions up to 35.6 %. Additionally, adopting the 

LEC design leads to a percentage reduction in life-cycle costs of 0.5 %.

Table 26-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2001 2004 2007 LEC

Energy Use -1.2 -10.3 -13.2 -26.4

Energy Cost -1.4 -14.6 -16.1 -31.9

Carbon Emissions -1.5 -17.5 -18.0 -35.6

Life-Cycle Cost 2.3 0.5 0.2 -0.5

Assuming natural gas is used for heating in Missouri, the adoption of newer editions of 

ASHRAE 90.1 lead to a shift in energy consumption from electricity to natural gas. In 

Missouri, natural gas is cheaper on a per-unit of energy basis and leads to less CO2e 

emissions per unit of energy consumed. As a result, the shift in consumption from 

electricity to natural gas leads to greater percentage savings in both energy costs and 

carbon emissions than the percentage savings in energy consumption.

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Missouri averaged 2.4 million m2 (25.4 million ft2) of new floor area annually. Table 

26-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption in GWh, energy costs in present value dollars (PV$), and 

energy-related carbon emissions in metric tCO2e from adopting the ASHRAE 90.1-2001, 

ASHRAE 90.1-2004, ASHRAE 90.1-2007, or LEC design as its state energy code over a 

10-year study period for one year’s worth of new construction. Additionally, the 

reductions from adopting the ASHRAE 90.1-2007 and LEC designs are obtained while 

decreasing life-cycle costs in present value dollars (PV$).
56

Table 26-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2001 2004 2007 LEC

Energy Use GWh -35.3 -345.1 -524.1 -984.7

Energy Cost PV$Million -$2.0 -$24.0 -$29.1 -$56.9

Carbon Emissions 1000 Metric tCO2e -35 -455 -502 -1001

Life-Cycle Cost PV$Million $37.3 $5.1 -$1.9 -$2.7

26.2 Within State Variation

One city in Missouri, St. Louis, has adopted its own state energy code based on ASHRAE 

90.1-2001. As a result, St. Louis realizes smaller reductions in energy use, energy costs, 

and carbon emissions than the other three cities within Zone 4A in Missouri. As shown in 

Table 26-3, buildings in St. Louis realize a reduction in energy consumption of 9.0 %

from the adoption of ASHRAE 90.1-2004, which is much lower than the reductions for 

the other three cities located in the same climate zone, which range from 10.3 % to 

11.5 %. The relative difference is minimal because the energy efficiency requirements 

defined in ASHRAE 90.1-1999 and ASHRAE 90.1-2001 are nearly identical.

Table 26-3 Average Percentage Change from Adoption of ASHRAE 90.1-2004 by 

City – 10 Yr Study Period

Cities Zone Metric

Energy Use Energy Costs Carbon Emissions Life-Cycle Costs

Columbia 4A -10.4 -14.9 -17.6 1.2

Kansas 4A -10.3 -14.7 -17.1 1.4

Springfield 4A -11.5 -15.7 -16.9 1.0

St. Louis 4A -9.0 -13.2 -15.4 -1.6

Average -10.3 -14.6 -16.7 0.5

26.3 The Bottom Line

Missouri could benefit from the adoption of a state energy code, particularly by taking an 

aggressive approach at increasing new building energy efficiency requirements. Adopting 

the LEC design, which is based on the energy efficiency requirements defined in 

ASHRAE 189.1-2009, leads to greater reductions in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs than adopting any edition of 

ASHRAE 90.1. If Missouri were to adopt a state energy code similar to the majority of 

states in the U.S. (ASHRAE 90.1-2007), it could still realize savings, although much 

smaller, in energy consumption, energy costs, and energy-related carbon emission while 

decreasing life-cycle costs. These are conservative estimates because a building’s lifetime 

is significantly longer than the 10-year study period length. As the study period increases,

operating energy becomes a more significant driver of overall costs, which will drive lifecycle cost savings up.
57

27 Montana

Montana has adopted ASHRAE 90.1-2007 as its state energy code, and is located in the 

Mountain Census Division and Climate Zone 6B.

27.1 Statewide Results

Table 27-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (13.3 %), energy costs (16.7 %), and energy-related 

carbon emissions (16.3 %), and life-cycle costs (0.4 %). Assuming natural gas is used for 

heating in Montana, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In Montana, natural gas is cheaper on a 

per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 27-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -13.3

Energy Cost -16.7

Carbon Emissions -16.3

Life-Cycle Cost -0.4

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Montana averaged 0.2 million m2 (2.6 million ft2

) of new floor area annually. Table 

27-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (52 GWh), energy costs ($2.9 million), energy-related carbon 

emissions (24 000 metric tons), and life-cycle costs ($523 393) from adopting the LEC 

design as its state energy code over a 10-year study period for one year’s worth of new 

construction.

Table 27-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -52.5

Energy Cost PV$Million -$2.9

Carbon Emissions 1000 Metric tCO2e -24

Life-Cycle Cost PV$Million -$0.5
58

27.2 The Bottom Line

Montana could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
59

28 Nebraska

Nebraska has adopted ASHRAE 90.1-2007 as its state energy code for commercial 

buildings, and is located in the West North Central Census Division and Climate 

Zone 5A.

28.1 Statewide Results

Table 28-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (13.7 %), energy costs (19.9 %), and energy-related 

carbon emissions (20.7 %), and life-cycle costs (0.5 %). Assuming natural gas is used for 

heating in Nebraska, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In Nebraska, natural gas is cheaper on a 

per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 28-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -13.7

Energy Cost -19.9

Carbon Emissions -20.7

Life-Cycle Cost -0.5

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Nebraska averaged 0.9 million m

2 (9.9 million ft2

) of new floor area annually. Table 

28-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (171 GWh), energy costs ($11 million), energy-related carbon 

emissions (167 000 metric tons), and life-cycle costs ($1.4 million) from adopting the 

LEC design as its state energy code over a 10-year study period for one year’s worth of 

new construction.

Table 28-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -170.8

Energy Cost PV$Million -$11.0

Carbon Emissions 1000 Metric tCO2e -167

Life-Cycle Cost PV$Million -$1.4
60

28.2 The Bottom Line

Nebraska could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
61

29 Nevada

Nevada is one of two states in the West Census Region that have adopted ASHRAE 

90.1-2004 as their state energy code for commercial buildings, is located in the Mountain 

Census Division, and spans two climate zones (Zone 3B and Zone 4B).

29.1 Statewide Results

Table 29-1 shows that, on average, adopting ASHRAE 90.1-2007 or the LEC design lead 

to percentage reductions in energy consumption, energy costs, energy-related carbon 

emissions, and life-cycle costs with the LEC design leading to much greater percentage 

reductions.

Table 29-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2007 LEC

Energy Use -3.4 -17.8

Energy Cost -1.7 -22.4

Carbon Emissions -2.2 -21.0

Life-Cycle Cost -0.4 -1.6

Assuming natural gas is used for heating in Nevada, the adoption of ASHRAE 90.1-2007

newer editions of ASHRAE 90.1 leads to a shift in energy consumption from natural gas

to electricity. In Nevada, natural gas is cheaper on a per-unit of energy basis and leads to 

less CO2e emissions per unit of energy consumed. As a result the shift in consumption 

from natural gas to electricity leads to smaller percentage savings in both energy costs 

and carbon emissions than the percentage savings in energy consumption. The opposite 

occurs for the adoption of the LEC design, where there is a shift from electricity to 

natural gas and the percentage reduction is greater for energy costs and carbon emissions 

relative to energy consumption.

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Nevada averaged 3.5 million m2 (37.8 million ft2

) of new floor area annually. Table 

29-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption in GWh, energy costs in present value dollars (PV$), 

energy-related carbon emissions in metric tCO2e, and life-cycle costs in present value 

dollars (PV$) from adopting the ASHRAE 90.1-2007 or LEC design as its state energy 

code over a 10-year study period for one year’s worth of new construction.
62

Table 29-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2007 LEC

Energy Use GWh -117.3 -709.0

Energy Cost PV$Million -$2.9 -$59.7

Carbon Emissions 1000 Metric tCO2e -25 -327

Life-Cycle Cost PV$Million -$6.3 -$17.9

29.2 The Bottom Line

Nevada could benefit from the adoption of a state energy code, particularly by taking an 

aggressive approach at increasing new building energy efficiency requirements. Adopting 

the LEC design, which is based on the energy efficiency requirements defined in 

ASHRAE 189.1-2009, leads to greater reductions in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs than adopting ASHRAE 90.1-2007. 

If Nevada were to adopt a state energy code similar to the majority of states in the U.S. 

(ASHRAE 90.1-2007), it could still realize savings, although much smaller, in energy 

consumption, energy costs, and energy-related carbon emission while decreasing

life-cycle costs. These are conservative estimates because a building’s lifetime is 

significantly longer than the 10-year study period length. As the study period increases,

operating energy becomes a more significant driver of overall costs, which will drive lifecycle cost savings up.
63

30 New Hampshire

New Hampshire is located in the New England Census Division and has adopted 

ASHRAE 90.1-2007 as its state energy code for commercial buildings. New Hampshire 

spans two climate zones with the southern portion of the state located in Zone 5A and the 

northern portion in Zone 6A. Only one city, Concord, is simulated for this study and is 

located in Zone 6A.

30.1 Statewide Results

Table 30-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (12.8 %), energy costs (16.7 %), and energy-related 

carbon emissions (16.0 %), and life-cycle costs (1.4 %). Assuming natural gas is used for 

heating in New Hampshire, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In New Hampshire, natural gas is cheaper on

a per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 30-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -12.8

Energy Cost -16.7

Carbon Emissions -16.0

Life-Cycle Cost -1.4

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in New Hampshire averaged 0.6 million m

2 (5.9 million ft2

) of new floor area annually. 

Table 30-2 shows that based on its average new construction, the state would realize 

reductions in energy consumption (108 GWh), energy costs ($10.9 million), 

energy-related carbon emissions (59 000 metric tons), and life-cycle costs ($5.8 million) 

from adopting the LEC design as its state energy code over a 10-year study period for one 

year’s worth of new construction.
64

Table 30-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -108.0

Energy Cost PV$Million -$10.9

Carbon Emissions 1000 Metric tCO2e -59

Life-Cycle Cost PV$Million -$5.8

30.2 The Bottom Line

New Hampshire could benefit from the adoption of the LEC design as its state energy 

code, which is based on the energy efficiency requirements defined in ASHRAE 

189.1-2009. Adoption of the LEC design leads to reduction in energy consumption, 

energy costs, energy-related carbon emissions, and life-cycle costs. These are 

conservative estimates because a building’s lifetime is significantly longer than the 

10-year study period length. As the study period increases, operating energy becomes a 

more significant driver of overall costs, which will drive life-cycle cost savings up.
65

31 New Jersey

New Jersey has adopted ASHRAE 90.1-2007 as its state energy code for commercial 

buildings, and is located in the Middle Atlantic Census Division and Climate Zone 4A.

31.1 Statewide Results

Table 31-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (14.7 %), energy costs (21.2 %), and energy-related 

carbon emissions (19.7 %), and life-cycle costs (1.2 %). Assuming natural gas is used for 

heating in New Jersey, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In New Jersey, natural gas is cheaper on a 

per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 31-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -14.7

Energy Cost -21.2

Carbon Emissions -19.7

Life-Cycle Cost -1.2

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in New Jersey averaged 3.5 million m2 (37.4 million ft2

) of new floor area annually. 

Table 31-2 shows that based on its average new construction, the state would realize 

reductions in energy consumption (582 GWh), energy costs ($73 million), energy-related 

carbon emissions (437 000 metric tons), and life-cycle costs ($21 million) from adopting 

the LEC design as its state energy code over a 10-year study period for one year’s worth 

of new construction.

Table 31-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -581.6

Energy Cost PV$Million -$72.7

Carbon Emissions 1000 Metric tCO2e -437

Life-Cycle Cost PV$Million -$20.8
66

31.2 The Bottom Line

New Jersey could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
67

32 New Mexico

New Mexico has adopted ASHRAE 90.1-2007 as its state energy code, is located in the 

Mountain Census Division, and spans three climate zones (Zone 3B, Zone 4B, and 

Zone 5B).

32.1 Statewide Results

Table 32-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (17.7 %), energy costs (22.9 %), and energy-related 

carbon emissions (22.9 %), and life-cycle costs (1.0 %). Assuming natural gas is used for 

heating in New Mexico, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In New Mexico, natural gas is cheaper on a 

per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 32-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -17.7

Energy Cost -22.9

Carbon Emissions -22.9

Life-Cycle Cost -1.0

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in New Mexico averaged 0.8 million m

2 (8.8 million ft2

) of new floor area annually. 

Table 32-2 shows that based on its average new construction, the state would realize 

reductions in energy consumption (154 GWh), energy costs ($11.7 million), energyrelated carbon emissions (146 000 metric tons), and life-cycle costs ($5.5 million) from 

adopting the LEC design as its state energy code over a 10-year study period for one 

year’s worth of new construction.

Table 32-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -153.7

Energy Cost PV$Million -$11.7

Carbon Emissions 1000 Metric tCO2e -146

Life-Cycle Cost PV$Million -$5.5
68

32.2 The Bottom Line

New Mexico could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
69

33 New York

New York has adopted ASHRAE 90.1-2007 as its state energy code, is located in the 

Middle Atlantic Census Division, and spans three climate zones (Zone 4A, Zone 5A, and 

Zone 6A).

33.1 Statewide Results

Table 33-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (12.6 %), energy costs (19.7 %), and energy-related 

carbon emissions (16.7 %), and life-cycle costs (1.3 %). Assuming natural gas is used for 

heating in New York, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In New York, natural gas is cheaper on a 

per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 33-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -12.6

Energy Cost -19.7

Carbon Emissions -16.7

Life-Cycle Cost -1.3

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in New York averaged 6.1 million m

2 (65.3 million ft2

) of new floor area annually. Table 

33-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (1038 GWh), energy costs ($132 million), energy-related carbon 

emissions (561 000 metric tons), and life-cycle costs ($37 million) from adopting the 

LEC design as its state energy code over a 10-year study period for one year’s worth of 

new construction.

Table 33-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -1037.6

Energy Cost PV$Million -$132.5

Carbon Emissions 1000 Metric tCO2e -561

Life-Cycle Cost PV$Million -$37.1
70

33.2 Within State Variation

Cities considered in this study span across three climate zones, each of which has its own 

energy efficiency requirements for the LEC design. As a result, there is some variation in 

results across climate zones in New York. As shown in Table 33-3, buildings in the 

warmest climate zone (Zone 4A) realize the greatest average reductions in energy 

consumption (13.9 %) from the adoption of the LEC design followed by buildings in 

Zone 6A (12.7 %) and Zone 5A (12.2 %). There is minimal variation within climate 

zones (less than 1.0 %).

Table 33-3 Average Percentage Change from Adoption of the LEC design by 

Climate Zone and City – 10 Yr Study Period

Zone Metric

Energy Use Energy Costs Carbon Emissions Life-Cycle Costs

4A -13.9 -21.4 -18.6 -1.2

5A -12.2 -20.3 -17.0 -1.5

6A -12.7 -17.7 -15.5 -1.2

33.3 The Bottom Line

New York could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
71

34 North Carolina

North Carolina is located in the South Atlantic Census Division and has adopted 

ASHRAE 90.1-2007 as its state energy code for commercial buildings. North Carolina 

spans three climate zones with the southern portion of the state located in Zone 3A, the 

central and northeast portions in Zone 4A, and the northwest portion in Zone 5A. All 

cities simulated for this study are located in Zone 3A and Zone 4A.

34.1 Statewide Results

Table 34-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (17.1 %), energy costs (20.1 %), and energy-related 

carbon emissions (21.0 %), and life-cycle costs (0.9 %). Assuming natural gas is used for 

heating in North Carolina, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In North Carolina, natural gas is cheaper on a 

per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 34-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -17.1

Energy Cost -20.1

Carbon Emissions -21.0

Life-Cycle Cost -0.9

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in North Carolina averaged 4.4 million m

2 (47.8 million ft2

) of new floor area annually. 

Table 34-2 shows that based on its average new construction, the state would realize 

reductions in energy consumption (828 GWh), energy costs ($56 million), energy-related 

carbon emissions (585 000 metric tons), and life-cycle costs ($20 million) from adopting 

the LEC design as its state energy code over a 10-year study period for one year’s worth 

of new construction.
72

Table 34-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -827.9

Energy Cost PV$Million -$56.2

Carbon Emissions 1000 Metric tCO2e -585

Life-Cycle Cost PV$Million -$20.3

34.2 The Bottom Line

North Carolina could benefit from the adoption of the LEC design as its state energy 

code, which is based on the energy efficiency requirements defined in ASHRAE 

189.1-2009. Adoption of the LEC design leads to reduction in energy consumption, 

energy costs, energy-related carbon emissions, and life-cycle costs. These are 

conservative estimates because a building’s lifetime is significantly longer than the 

10-year study period length. As the study period increases, operating energy becomes a 

more significant driver of overall costs, which will drive life-cycle cost savings up.
73

35 North Dakota

North Dakota is located in the West North Central Census Division and spans two

climate zones (Zone 6 and Zone 7). The state does not have a commercial building 

energy code and, for this analysis, is assumed to build to the current minimum industry 

practices represented by ASHRAE 90.1-1999 requirements.

35.1 Statewide Results

Table 35-1 shows that, on average, adopting newer editions of ASHRAE 90.1 or the LEC 

design lead to percentage reductions in energy consumption up to 21.2 %, energy costs

up to 28.5 %, and energy-related carbon emissions up to 29.9 %. Additionally, adopting

the LEC design leads to percentage reductions in life-cycle costs of 0.2 %.

Table 35-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2001 2004 2007 LEC

Energy Use -0.8 -2.9 -8.9 -21.2

Energy Cost -1.1 -11.7 -14.6 -28.5

Carbon Emissions -1.2 -13.3 -15.7 -29.9

Life-Cycle Cost 2.1 0.7 0.1 -0.2

Assuming natural gas is used for heating in North Dakota, the adoption of newer editions 

of ASHRAE 90.1 leads to a shift in energy consumption from electricity to natural gas. In 

North Dakota, natural gas is cheaper on a per-unit of energy basis and leads to less CO2e 

emissions per unit of energy consumed. As a result, the shift in consumption from 

electricity to natural gas leads to greater percentage savings in both energy costs and 

carbon emissions than the percentage savings in energy consumption.

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in North Dakota averaged 0.2 million m

2 (2.5 million ft2

) of new floor area annually. 

Table 35-2 shows that based on its average new construction, the state would realize 

reductions in energy consumption in GWh, energy costs in present value dollars (PV$), 

and energy-related carbon emissions in metric tCO2e from adopting a newer edition of 

ASHRAE 90.1 or the LEC design as its state energy code over a 10-year study period for 

one year’s worth of new construction. The reductions from the adoption of the ASHRAE 

90.1-2007 and LEC designs are realized without increasing life-cycle costs in present 

value dollars (PV$).
74

Table 35-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2001 2004 2007 LEC

Energy Use GWh -3.2 -12.9 -45.7 -104.5

Energy Cost PV$Million -$0.2 -$1.7 -$2.4 -$4.8

Carbon Emissions 1000 Metric tCO2e -3 -29 -38 -76

Life-Cycle Cost PV$Million $3.4 $0.8 -$0.0 -$0.0

For North Dakota, the amount of new building construction for each building type will 

impact the overall cost-effectiveness of adopting a state energy code. For example, the 

non-weighted average percentage change in life-cycle costs from adopting ASHRAE 

90.1-2007 implies a small increase in life-cycle costs (0.1 %). However, the building 

types that account for the most amount of new construction (retail stores, high schools, 

and hotels) each lead to life-cycle cost savings, which offset the impacts from the 

building types that increase life-cycle costs (3-story office buildings, 8-story office 

buildings and restaurants).

35.2 The Bottom Line

North Dakota could benefit from the adoption of a state energy code, particularly by 

taking an aggressive approach at increasing new building energy efficiency requirements. 

Adopting the LEC design, which is based on the energy efficiency requirements defined 

in ASHRAE 189.1-2009, leads to greater energy consumption, energy cost, and 

energy-related carbon emissions savings than adopting any edition of ASHRAE 90.1, and 

does so without increasing life-cycle costs. If North Dakota were to adopt a state energy 

code similar to the majority of states in the U.S. (ASHRAE 90.1-2007), it would realize 

smaller savings in energy consumption, energy costs, and energy-related carbon 

emission, and also does not increase life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
75

36 Ohio

Ohio has adopted ASHRAE 90.1-2007 as its state energy code for commercial buildings, 

is located in the East North Central Census Division, and spans two climate zones 

(Zone 4A and Zone 5A).

36.1 Statewide Results

Table 36-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (13.2 %), energy costs (19.2 %), and energy-related 

carbon emissions (20.2 %), and life-cycle costs (0.8 %). Assuming natural gas is used for 

heating in Ohio, the adoption of the LEC design leads to a shift in energy consumption 

from electricity to natural gas. In Ohio, natural gas is cheaper on a per-unit of energy 

basis and leads to less CO2e emissions per unit of energy consumed. As a result, the shift 

in consumption from electricity to natural gas leads to greater percentage savings in both 

energy costs and carbon emissions than the percentage savings in energy consumption.

Table 36-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -13.2

Energy Cost -19.2

Carbon Emissions -20.2

Life-Cycle Cost -0.8

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Ohio averaged 4.9 million m2 (52.8 million ft2

) of new floor area annually. Table 36-2

shows that based on its average new construction the state would realize reductions in 

energy consumption (827 GWh), energy costs ($74 million), energy-related carbon 

emissions (838 000 metric tons), and life-cycle costs ($34 million) from adopting the 

LEC design as its state energy code over a 10-year study period for one year’s worth of 

new construction.

Table 36-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -826.8

Energy Cost PV$Million -$74.1

Carbon Emissions 1000 Metric tCO2e -838

Life-Cycle Cost PV$Million -$33.9
76

36.2 The Bottom Line

Ohio could benefit from the adoption of the LEC design as its state energy code, which is 

based on the energy efficiency requirements defined in ASHRAE 189.1-2009. Adoption 

of the LEC design leads to reduction in energy consumption, energy costs, energy-related 

carbon emissions, and life-cycle costs. These are conservative estimates because a 

building’s lifetime is significantly longer than the 10-year study period length. As the 

study period increases, operating energy becomes a more significant driver of overall 

costs, which will drive life-cycle cost savings up.
77

37 Oklahoma

Oklahoma is located in the West South Central Census Division and spans two climate 

zones, Zone 2A across most of the state and Zone 3B in the western “panhandle.” The 

state does not have a commercial building energy code and, for this analysis, is assumed 

to build to the current minimum industry practices represented by ASHRAE 90.1-1999

requirements.

37.1 Statewide Results

Table 37-1 shows that, on average, adopting newer editions of ASHRAE 90.1 or the LEC 

design lead to percentage reductions in energy consumption up to 27.0 %, energy costs

up to 33.3 %, and energy-related carbon emissions up to 37.9 %. Additionally, adopting

the LEC design leads to percentage reductions in life-cycle costs of 0.5 % while adopting 

ASHRAE 90.1-2007 leads to no change in life-cycle costs.

Table 37-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2001 2004 2007 LEC

Energy Use -2.0 -13.0 -13.9 -27.0

Energy Cost -2.2 -17.0 -18.5 -33.3

Carbon Emissions -2.3 -19.8 -21.9 -37.9

Life-Cycle Cost 2.5 0.3 0.0 -0.5

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Oklahoma averaged 1.6 million m

2 (17.1 million ft2

) of new floor area annually. Table 

37-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption in GWh, energy costs in present value dollars (PV$), and 

energy-related carbon emissions in metric tCO2e from adopting a newer edition of 

ASHRAE 90.1 as its state energy code over a 10-year study period for one year’s worth of 

new construction, but leads to an increase in life-cycle costs. The adoption of the LEC 

design not only realizes much larger reductions in energy use, energy costs, and carbon 

emissions, but does so while decreasing life-cycle costs in present value dollars (PV$).

Table 37-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2001 2004 2007 LEC

Energy Use GWh -38.1 -258.7 -300.5 -598.1

Energy Cost PV$Million -$2.0 -$16.6 -$18.6 -$35.4

Carbon Emissions 1000 Metric tCO2e -37 -330 -365 -679

Life-Cycle Cost PV$Million $26.2 $5.5 $5.7 -$0.7
78

37.2 The Bottom Line

Oklahoma could benefit from the adoption of a state energy code, particularly by taking 

an aggressive approach at increasing new building energy efficiency requirements. 

Adopting the LEC design, which is based on the energy efficiency requirements defined 

in ASHRAE 189.1-2009, leads to greater reductions in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs than adopting ASHRAE 90.1-2007. 

If Oklahoma were to adopt a state energy code similar to the majority of states in the U.S. 

(ASHRAE 90.1-2007), it could still realize savings in energy consumption, energy costs, 

and energy-related carbon emission, but at an increase in life-cycle costs. These are 

conservative estimates because a building’s lifetime is significantly longer than the 

10-year study period length. As the study period increases, operating energy becomes a 

more significant driver of overall costs, which will drive life-cycle cost savings up. As a 

result, the adoption of different editions of ASHRAE 90.1 may become cost-effective as 

the investment time horizon is extended further into the future.
79

38 Oregon

Oregon has adopted ASHRAE 90.1-2007 as its state energy code, is located in the Pacific 

Census Division, and spans two climate zones (Zone 4C and Zone 5B).

38.1 Statewide Results

Table 38-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (15.0 %), energy costs (19.1 %), energy-related carbon 

emissions (19.4 %), and life-cycle costs (0.6 %). Assuming natural gas is used for heating 

in Oregon, the adoption of the LEC design leads to a shift in energy consumption from 

electricity to natural gas. In Oregon, natural gas is cheaper on a per-unit of energy basis 

and leads to less CO2e emissions per unit of energy consumed. As a result, the shift in 

consumption from electricity to natural gas leads to greater percentage savings in both 

energy costs and carbon emissions than the percentage savings in energy consumption.

Table 38-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -15.0

Energy Cost -19.1

Carbon Emissions -19.4

Life-Cycle Cost -0.6

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Oregon averaged 1.7 million m

2 (18.8 million ft2

) of new floor area annually. Table 

38-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (261 GWh), energy costs ($17.4 million), and energy-related 

carbon emissions (146 000 metric tons) from adopting the LEC design as its state energy 

code over a 10-year study period for one year’s worth of new construction. However, 

these reductions are realized with an increase in life-cycle costs of $400 000.

Table 38-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -261.4

Energy Cost PV$Million -$17.4

Carbon Emissions 1000 Metric tCO2e -146

Life-Cycle Cost PV$Million $0.4

For Oregon, the amount of new building construction for each building type impacts the 

overall cost-effectiveness of adopting the LEC design. The non-weighted average 

percentage change in life-cycle costs from adopting the LEC design implies a decrease in 
80

life-cycle costs (-0.6 %). However, three of the four building types that account for the 

most amount of new construction (retail stores, 4-story apartments, and 6-story 

apartments) lead to an increase in life-cycle costs while the fourth (hotels) only slightly 

decreases life-cycle costs. The total life-cycle cost savings from the other building types 

is not large enough to offset these increases in life-cycle costs. As a result, the net impact 

is a small increase in life-cycle costs.

38.2 The Bottom Line

Oregon could benefit from the adoption of the LEC design as its state energy code, which 

is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. Adoption 

of the LEC design leads to a reduction in energy consumption, energy costs, 

energy-related carbon emissions, but with an increase in life-cycle costs of $400 000. 

These are conservative estimates because a building’s lifetime is significantly longer than 

the 10-year study period length. As the study period increases, operating energy becomes 

a more significant driver of overall costs, which will drive life-cycle cost savings up. As a 

result, the adoption of the LEC design may become cost-effective as the investment time 

horizon is extended further into the future.
81

39 Pennsylvania

Pennsylvania has adopted ASHRAE 90.1-2007 as its state energy code for commercial 

buildings, is located in the Middle Atlantic Census Division, and spans three climate 

zones (Zone 4A, Zone 5A, and Zone 6A).

39.1 Statewide Results

Table 39-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (13.1 %), energy costs (18.3 %), energy-related carbon 

emissions (19.2 %), and life-cycle costs (0.7 %). Assuming natural gas is used for heating 

in Pennsylvania, the adoption of the LEC design leads to a shift in energy consumption 

from electricity to natural gas. In Pennsylvania, natural gas is cheaper on a per-unit of 

energy basis and leads to less CO2e emissions per unit of energy consumed. As a result, 

the shift in consumption from electricity to natural gas leads to greater percentage savings 

in both energy costs and carbon emissions than the percentage savings in energy 

consumption.

Table 39-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -13.1

Energy Cost -18.3

Carbon Emissions -19.2

Life-Cycle Cost -0.7

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Pennsylvania averaged 4.7 million m

2 (50.2 million ft2

) of new floor area annually. 

Table 39-2 shows that based on its average new construction, the state would realize 

reductions in energy consumption (765 GWh), energy costs ($64 million), energy-related 

carbon emissions (629 000 metric tons), and life-cycle costs ($18 million) from adopting 

the LEC design as its state energy code over a 10-year study period for one year’s worth 

of new construction.

Table 39-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -764.9

Energy Cost PV$Million -$63.9

Carbon Emissions 1000 Metric tCO2e -629

Life-Cycle Cost PV$Million -$18.2
82

39.2 Within State Variation

Cities considered in this study span across three climate zones, each of which has its own 

energy efficiency requirements for the LEC design. As a result, there is some variation in 

results across climate zones and across cities within climate zones in Pennsylvania. As 

shown in Table 39-3, buildings in the warmest climate zone (Zone 4A) realize the 

greatest average reductions in energy consumption (14.6 %) from the adoption of the 

LEC design followed by buildings in Zone 5A (13.2 %) and Zone 6A (11.0 %). The

average percentage reduction in energy consumption varies within Zone 5A from 12.4 % 

in Erie and Wilkes-Barre to 14.0 % in Harrisburg.

Table 39-3 Average Percentage Change from Adoption of the LEC design by 

Climate Zone and City – 10 Yr Study Period

Zone City Metric

Energy Use Energy Costs Carbon Emissions Life-Cycle Costs

4A -14.6 -19.2 -20.2 -0.3

5A -13.2 -18.4 -19.5 -0.7

Allentown -13.6 -18.7 -19.8 -0.5

Erie -12.4 -17.8 -19.0 -0.7

Harrisburg -14.0 -18.9 -20.0 -0.7

Pittsburgh -13.7 -18.8 -19.9 -0.9

Wilkes-Barre -12.4 -17.8 -19.0 -0.8

Williamsport -13.1 -18.3 -19.4 -0.9

6A -11.0 -16.8 -18.1 -0.8

39.3 The Bottom Line

Pennsylvania could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reductions in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
83

40 Rhode Island

Rhode Island has adopted ASHRAE 90.1-2007 as its state energy code for commercial 

buildings, and is located in the New England Census Division. Only one city, Providence, 

is simulated for this study, and is located in Zone 5A.

40.1 Statewide Results

Table 40-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (13.4 %), energy costs (19.1 %), and energy-related 

carbon emissions (18.7 %), and life-cycle costs (1.2 %). Assuming natural gas is used for 

heating in Rhode Island, the adoption of the LEC design leads to a shift in energy 

consumption from electricity to natural gas. In Rhode Island, natural gas is cheaper on a 

per-unit of energy basis and leads to less CO2e emissions per unit of energy consumed. 

As a result, the shift in consumption from electricity to natural gas leads to greater 

percentage savings in both energy costs and carbon emissions than the percentage savings 

in energy consumption.

Table 40-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -13.4

Energy Cost -19.1

Carbon Emissions -18.7

Life-Cycle Cost -1.2

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Rhode Island averaged 0.3 million m

2 (3.6 million ft2

) of new floor area annually. 

Table 40-2 shows that based on its average new construction, the state would realize 

reductions in energy consumption (55 GWh), energy costs ($6.6 million), energy-related 

carbon emissions (38 000 metric tons), and life-cycle costs ($3.1 million) from adopting 

the LEC design as its state energy code over a 10-year study period for one year’s worth 

of new construction.

Table 40-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -55.3

Energy Cost PV$Million -$6.6

Carbon Emissions 1000 Metric tCO2e -38

Life-Cycle Cost PV$Million -$3.1
84

40.2 The Bottom Line

Rhode Island could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
85

41 South Carolina

South Carolina is one of two states in the South Census Region that have adopted 

ASHRAE 90.1-2004 as their state energy code for commercial buildings, and is located in 

the South Atlantic Census Division and Climate Zone 3A.

41.1 Statewide Results

Table 41-1 shows that, on average, adopting ASHRAE 90.1-2007 or the LEC design lead 

to percentage reductions in energy consumption, energy costs, energy-related carbon 

emissions, and life-cycle costs with the LEC design leading to much greater percentage 

reductions. Assuming natural gas is used for heating in South Carolina, the adoption of 

ASHRAE 90.1-2007 or the LEC design lead to a shift in energy consumption from 

electricity to natural gas. In South Carolina, natural gas is cheaper on a per-unit of energy 

basis and leads to less CO2e emissions per unit of energy consumed. As a result, the shift 

in consumption from electricity to natural gas leads to greater percentage savings in both 

energy costs and carbon emissions than the percentage savings in energy consumption.

Table 41-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2007 LEC

Energy Use -1.8 -18.7

Energy Cost -2.7 -22.4

Carbon Emissions -2.9 -22.9

Life-Cycle Cost -0.3 -0.9

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in South Carolina averaged 2.7 million m

2 (29.3 million ft2

) of new floor area annually. 

Table 41-2 shows that based on its average new construction, the state would realize 

reductions in energy consumption in GWh, energy costs in present value dollars (PV$), 

energy-related carbon emissions in metric tCO2e, and life-cycle costs in present value 

dollars (PV$) from adopting the ASHRAE 90.1-2007 or LEC design as its state energy 

code over a 10-year study period for one year’s worth of new construction.

Table 41-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2007 LEC

Energy Use GWh -92.2 -594.5

Energy Cost PV$Million -$6.5 -$43.8

Carbon Emissions 1000 Metric tCO2e -61 -412

Life-Cycle Cost PV$Million -$2.9 -$12.2
86

41.2 The Bottom Line

South Carolina could benefit from the adoption of a state energy code, particularly by 

taking an aggressive approach at increasing new building energy efficiency requirements. 

Adopting the LEC design, which is based on the energy efficiency requirements defined 

in ASHRAE 189.1-2009, leads to greater reductions in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs than adopting ASHRAE 90.1-2007. 

If South Carolina were to adopt a state energy code similar to the majority of states in the 

U.S. (ASHRAE 90.1-2007), it could still realize savings, although much smaller, in 

energy consumption, energy costs, and energy-related carbon emission while decreasing 

life-cycle costs. These are conservative estimates because a building’s lifetime is 

significantly longer than the 10-year study period length. As the study period increases,

operating energy becomes a more significant driver of overall costs, which will drive lifecycle cost savings up.
87

42 South Dakota

South Dakota is located in the West North Central Census Division, and spans two

climate zones (Zone 5 and Zone 6). The state does not have a commercial building 

energy code and, for this analysis, is assumed to build to the current minimum industry 

practices represented by ASHRAE 90.1-1999 requirements.

42.1 Statewide Results

Table 42-1 shows that, on average, adopting newer editions of ASHRAE 90.1 or the LEC 

design lead to percentage reductions in energy consumption up to 21.8 %, energy costs

up to 29.5 %, and energy-related carbon emissions up to 30.6 %. Additionally, adopting

ASHRAE 90.1-2004, ASHRAE 90.1-2007, or the LEC design leads to percentage 

reductions in life-cycle costs up to 1.3 %.

Table 42-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2001 2004 2007 LEC

Energy Use -0.7 -6.5 -10.5 -21.8

Energy Cost -0.9 -14.2 -15.7 -29.5

Carbon Emissions -0.9 -15.2 -16.5 -30.6

Life-Cycle Cost 1.4 -0.6 -0.9 -1.3

Assuming natural gas is used for heating in South Dakota, the adoption of newer editions 

of ASHRAE 90.1 leads to a shift in energy consumption from electricity to natural gas. In 

South Dakota, natural gas is cheaper on a per-unit of energy basis and leads to less CO2e 

emissions per unit of energy consumed. As a result, the shift in consumption from 

electricity to natural gas leads to greater percentage savings in both energy costs and 

carbon emissions than the percentage savings in energy consumption.

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in South Dakota averaged 0.3 million m2 (3.3 million ft2

) of new floor area annually. 

Table 42-2 shows that based on its average new construction, the state would realize 

reductions in energy consumption in GWh, energy costs in present value dollars (PV$), 

energy-related carbon emissions in metric tCO2e, and life-cycle costs in present value 

dollars (PV$) from adopting the ASHRAE 90.1-2004, ASHRAE 90.1-2007, or LEC design 

as its state energy code over a 10-year study period for one year’s worth of new 

construction.
88

Table 42-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2001 2004 2007 LEC

Energy Use GWh -3.4 -29.0 -57.5 -122.3

Energy Cost PV$Million -$0.2 -$2.6 -$3.1 -$6.5

Carbon Emissions 1000 Metric tCO2e -3 -41 -48 -98

Life-Cycle Cost PV$Million $2.9 -$0.7 -$1.4 -$2.4

42.2 The Bottom Line

South Dakota could benefit from the adoption of a state energy code, particularly by 

taking an aggressive approach at increasing new building energy efficiency requirements. 

Adopting the LEC design, which is based on the energy efficiency requirements defined 

in ASHRAE 189.1-2009, leads to greater reductions in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs than adopting any edition of

ASHRAE 90.1. If South Dakota were to adopt a state energy code similar to the majority 

of states in the U.S. (ASHRAE 90.1-2007), it could still realize savings, although much 

smaller, in energy consumption, energy costs, and energy-related carbon emission while 

decreasing life-cycle costs. These are conservative estimates because a building’s lifetime 

is significantly longer than the 10-year study period length. As the study period increases,

operating energy becomes a more significant driver of overall costs, which will drive lifecycle cost savings up.
89

43 Tennessee

Tennessee is one of two states in the South Census Region that have adopted ASHRAE 

90.1-2004 as their state energy code for commercial buildings, is located in the East 

South Central Census Division, and spans two climate zones (Zone 3A and Zone 4A).

43.1 Statewide Results

Table 43-1 shows that, on average, adopting ASHRAE 90.1-2007 or the LEC design lead 

to percentage reductions in energy consumption, energy costs, energy-related carbon 

emissions, and life-cycle costs with the LEC design leading to much greater percentage 

reductions. Assuming natural gas is used for heating in Tennessee, the adoption of newer 

editions of ASHRAE 90.1 leads to a shift in energy consumption from electricity to 

natural gas. In Tennessee, natural gas is cheaper on a per-unit of energy basis and leads to 

less CO2e emissions per unit of energy consumed. As a result, the shift in consumption 

from electricity to natural gas leads to greater percentage savings in both energy costs and 

carbon emissions than the percentage savings in energy consumption.

Table 43-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2007 LEC

Energy Use -2.3 -18.8

Energy Cost -1.2 -21.9

Carbon Emissions -1.0 -22.5

Life-Cycle Cost -0.3 -1.4

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Tennessee averaged 3.3 million m

2 (35.2 million ft2

) of new floor area annually. Table 

43-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption in GWh, energy costs in present value dollars (PV$), 

energy-related carbon emissions in metric tCO2e, and life-cycle costs in present value 

dollars (PV$) from adopting ASHRAE 90.1-2007 or the LEC design as its state energy 

code over a 10-year study period for one year’s worth of new construction.

Table 43-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2007 LEC

Energy Use GWh -172.6 -807.8

Energy Cost PV$Million -$6.5 -$58.7

Carbon Emissions 1000 Metric tCO2e -60 -627

Life-Cycle Cost PV$Million -$7.5 -$28.1
90

43.2 The Bottom Line

Tennessee could benefit from the adoption of a state energy code, particularly by taking 

an aggressive approach at increasing new building energy efficiency requirements. 

Adopting the LEC design, which is based on the energy efficiency requirements defined 

in ASHRAE 189.1-2009, leads to greater reductions in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs than adopting ASHRAE 90.1-2007. 

If Tennessee were to adopt a state energy code similar to the majority of states in the U.S. 

(ASHRAE 90.1-2007), it could still realize savings, although much smaller, in energy 

consumption, energy costs, and energy-related carbon emission while decreasing 

life-cycle costs. These are conservative estimates because a building’s lifetime is 

significantly longer than the 10-year study period length. As the study period increases,

operating energy becomes a more significant driver of overall costs, which will drive lifecycle cost savings up.
91

44 Texas

Texas has adopted ASHRAE 90.1-2007 as its state energy code for commercial buildings, 

is located in the West South Central Census Division, and spans three climate zones 

(Zone 2, Zone 3, and Zone 4).

44.1 Statewide Results

Table 44-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (17.8 %), energy costs (21.0 %), energy-related carbon 

emissions (21.1 %), and life-cycle costs (1.3 %). Assuming natural gas is used for heating 

in Texas, the adoption of the LEC design leads to a shift in energy consumption from 

electricity to natural gas. In Texas, natural gas is cheaper on a per-unit of energy basis 

and leads to less CO2e emissions per unit of energy consumed. As a result, the shift in 

consumption from electricity to natural gas leads to greater percentage savings in both 

energy costs and carbon emissions than the percentage savings in energy consumption.

Table 44-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -17.8

Energy Cost -21.0

Carbon Emissions -21.1

Life-Cycle Cost -1.3

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Texas averaged 14.4 million m2 (155.5 million ft2

) of new floor area annually. Table 

44-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (2832 GWh), energy costs ($234 million), energy-related carbon 

emissions (2.6 million metric tons), and life-cycle costs ($107 million) from adopting the 

LEC design as its state energy code over a 10-year study period for one year’s worth of 

new construction.

Table 44-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -2831.6

Energy Cost PV$Million -$234.5

Carbon Emissions 1000 Metric tCO2e -2630

Life-Cycle Cost PV$Million -$106.8
92

44.2 Within State Variation

Texas is one of the largest states in terms of land mass and spans three climate zones, 

over both wet and dry subzones (Zone 2, Zone 3, and Zone 4), and such as, the reductions 

vary across climate zones. As shown in Table 44-3, there is not much difference, on 

average, across climate zones (16.8 % to 18.0 %). However, there is significant variation 

across cities in Texas, even within climate zones, For example, the energy use savings 

realized by cities within Zone 2 vary from 16.6 % in Waco to 19.5 % in Corpus Christi.

Table 44-3 Average Percentage Change from Adoption of LEC by City – 10 Yr 

Study Period

44.3 The Bottom Line

Texas could benefit from the adoption of the LEC design as its state energy code, which 

is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. Adoption 

of the LEC design leads to reduction in energy consumption, energy costs, energy-related 

carbon emissions, and life-cycle costs. These are conservative estimates because a 

building’s lifetime is significantly longer than the 10-year study period length. As the 

study period increases, operating energy becomes a more significant driver of overall 

costs, which will drive life-cycle cost savings up.

Zone City Metric

Energy Use Energy Costs Carbon Emissions Life-Cycle Costs

Zone 2 -18.0 -20.5 -20.8 -1.2

2A Austin -17.2 -20.3 -20.6 -1.0

2A Brownsville -19.2 -20.1 -20.4 -1.5

2A Corpus Christi -19.5 -20.7 -21.0 -1.2

2A Houston -17.5 -20.3 -20.6 -1.1

2A Lufkin -17.3 -20.7 -21.1 -1.4

2A Port Arthur -17.9 -20.4 -20.8 -1.1

2A San Antonio -18.0 -21.0 -21.4 -1.1

2A Victoria -18.9 -20.7 -21.0 -1.3

2A Waco -16.6 -20.4 -20.8 -1.0

2B Del Rio -17.6 -20.0 -20.3 -1.6

Zone 3 -17.8 -21.7 -22.0 -1.3

Zone 4 -16.8 -22.5 -22.8 -1.1
93

45 Utah

Utah has adopted ASHRAE 90.1-2007 as its state energy code for commercial buildings, 

is located in the Mountain Census Division, and spans three climate zones (Zone 3B, 

Zone 5B, and Zone 6B).

45.1 Statewide Results

Table 45-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (15.1 %), energy costs (21.2 %), energy-related carbon 

emissions (19.6 %), and life-cycle costs (0.7 %). Assuming natural gas is used for heating 

in Utah, the adoption of the LEC design leads to a shift in energy consumption from 

electricity to natural gas. In Utah, natural gas is cheaper on a per-unit of energy basis and 

leads to less CO2e emissions per unit of energy consumed. As a result, the shift in 

consumption from electricity to natural gas leads to greater percentage savings in both 

energy costs and carbon emissions than the percentage savings in energy consumption.

Table 45-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -15.1

Energy Cost -21.2

Carbon Emissions -19.6

Life-Cycle Cost -0.7

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Utah averaged 1.7 million m2 (18.5 million ft2

) of new floor area annually. Table 45-2

shows that based on its average new construction, the state would realize reductions in 

energy consumption (287 GWh), energy costs ($18.8 million), energy-related carbon 

emissions (144 000 metric tons), and life-cycle costs ($5.4 million) from adopting the 

LEC design as its state energy code over a 10-year study period for one year’s worth of 

new construction.

Table 45-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -286.6

Energy Cost PV$Million -$18.8

Carbon Emissions 1000 Metric tCO2e -144

Life-Cycle Cost PV$Million -$5.4
94

45.2 The Bottom Line

Utah could benefit from the adoption of the LEC design as its state energy code, which is 

based on the energy efficiency requirements defined in ASHRAE 189.1-2009. Adoption 

of the LEC design leads to reduction in energy consumption, energy costs, energy-related 

carbon emissions, and life-cycle costs. These are conservative estimates because a 

building’s lifetime is significantly longer than the 10-year study period length. As the 

study period increases, operating energy becomes a more significant driver of overall 

costs, which will drive life-cycle cost savings up.
95

46 Vermont

Vermont has adopted ASHRAE 90.1-2007 as its state energy code for commercial 

buildings, and is located in the Northeast Census Division and Climate Zone 6A. Only 

one city, Burlington, is simulated for this study.

46.1 Statewide Results

Table 46-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (12.6 %), energy costs (16.4 %), energy-related carbon 

emissions (15.8 %), and life-cycle costs (1.2 %). Assuming natural gas is used for heating 

in Vermont, the adoption of the LEC design leads to a shift in energy consumption from 

electricity to natural gas. In Vermont, natural gas is cheaper on a per-unit of energy basis 

and leads to less CO2e emissions per unit of energy consumed. As a result, the shift in 

consumption from electricity to natural gas leads to greater percentage savings in both 

energy costs and carbon emissions than the percentage savings in energy consumption.

Table 46-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -12.6

Energy Cost -16.4

Carbon Emissions -15.8

Life-Cycle Cost -1.2

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Vermont averaged 0.2 million m2 (2.1 million ft2

) of new floor area annually. Table 

46-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (37 GWh), energy costs ($3.4 million), energy-related carbon 

emissions (21 000 metric tons), and life-cycle costs ($1.4 million) from adopting the LEC 

design as its state energy code over a 10-year study period for one year’s worth of new 

construction.

Table 46-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -37.3

Energy Cost PV$Million -$3.4

Carbon Emissions 1000 Metric tCO2e -21

Life-Cycle Cost PV$Million -$1.4
96

46.2 The Bottom Line

Vermont could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
97

47 Virginia

Virginia has adopted ASHRAE 90.1-2007 as its state energy code for commercial 

buildings, and is located in the South Atlantic Census Division and Climate Zone 4A.

47.1 Statewide Results

Table 47-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (17.0 %), energy costs (20.8 %), energy-related carbon 

emissions (21.6 %), and life-cycle costs (0.8 %). Assuming natural gas is used for heating 

in Virginia, the adoption of the LEC design leads to a shift in energy consumption from 

electricity to natural gas. In Virginia, natural gas is cheaper on a per-unit of energy basis 

and leads to less CO2e emissions per unit of energy consumed. As a result, the shift in 

consumption from electricity to natural gas leads to greater percentage savings in both 

energy costs and carbon emissions than the percentage savings in energy consumption.

Table 47-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -17.0

Energy Cost -20.8

Carbon Emissions -21.6

Life-Cycle Cost -0.8

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Virginia averaged 4.5 million m

2 (48.4 million ft2

) of new floor area annually. Table 

47-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (871 GWh), energy costs ($60 million), energy-related carbon 

emissions (695 000 metric tons), and life-cycle costs ($14 million) from adopting the 

LEC design as its state energy code over a 10-year study period for one year’s worth of 

new construction.

Table 47-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -871.3

Energy Cost PV$Million -$60.5

Carbon Emissions 1000 Metric tCO2e -695

Life-Cycle Cost PV$Million -$14.0
98

47.2 The Bottom Line

Virginia could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
99

48 Washington

Washington has adopted ASHRAE 90.1-2007 as its state energy code for commercial 

buildings, is located in the Pacific Census Division, and spans three climate zones 

(Zone 4C, Zone 5B, and Zone 6B).

48.1 Statewide Results

Table 48-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (13.6 %), energy costs (17.1 %), energy-related carbon 

emissions (18.1 %), and life-cycle costs (0.2 %). Assuming natural gas is used for heating 

in Washington, the adoption of the LEC design leads to a shift in energy consumption 

from electricity to natural gas. In Washington, natural gas is cheaper on a per-unit of 

energy basis and leads to less CO2e emissions per unit of energy consumed. As a result, 

the shift in consumption from electricity to natural gas leads to greater percentage savings 

in both energy costs and carbon emissions than the percentage savings in energy 

consumption.

Table 48-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -13.6

Energy Cost -17.1

Carbon Emissions -18.1

Life-Cycle Cost -0.2

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Washington averaged 3.7 million m

2 (39.9 million ft2

) of new floor area annually. 

Table 48-2 shows that based on its average new construction, the state would realize 

reductions in energy consumption (525 GWh), energy costs ($32 million), and energyrelated carbon emissions (267 000 metric tons) from adopting the LEC design as its state 

energy code over a 10-year study period for one year’s worth of new construction, but 

does so with an increase in life-cycle costs of over $11 million.

Table 48-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -525.0

Energy Cost PV$Million -$32.3

Carbon Emissions 1000 Metric tCO2e -267

Life-Cycle Cost PV$Million $11.5
100

For Washington, the amount of new building construction for each building type impacts 

the overall cost-effectiveness of adopting the LEC design. The non-weighted average 

percentage change in life-cycle costs from adopting the LEC design implies a decrease in 

life-cycle costs (-0.2 %). However, the four building types that account for the most 

amount of new construction (retail stores, 6-story apartments, high schools, and 4-story 

apartments) lead to an increase in life-cycle costs, and overwhelm the impacts from the 

three building types that reduce life-cycle costs (3-story office buildings, 8-story office 

buildings, and restaurants).

48.2 The Bottom Line

Washington could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, and 

energy-related carbon emissions. However, these savings are realized with an increase in 

life-cycle costs of over $11 million. These are conservative estimates because a 

building’s lifetime is significantly longer than the 10-year study period length. As the 

study period increases, operating energy becomes a more significant driver of overall 

costs, which will drive life-cycle cost savings up. As a result, the adoption of the LEC 

design may become cost-effective as the investment time horizon is extended further into 

the future.
101

49 West Virginia

West Virginia is one of two states in the South Census Region that have adopted 

ASHRAE 90.1-2001 as their state energy code for commercial buildings, is located in the

South Atlantic Census Division, and spans two climate zones (Zone 4A and Zone 5A).

49.1 Statewide Results

Table 49-1 shows that, on average, adopting newer editions of ASHRAE 90.1 or the LEC 

design lead to percentage reductions in energy consumption up to 25.7 %, energy costs

up to 28.8 %, energy-related carbon emissions up to 34.6 %, and life-cycle costs up to 

2.2 %. Assuming natural gas is used for heating in West Virginia, the adoption of newer 

editions of ASHRAE 90.1 leads to a shift in energy consumption from electricity to 

natural gas. In West Virginia, natural gas is cheaper on a per-unit of energy basis and 

leads to less CO2e emissions per unit of energy consumed. As a result, the shift in 

consumption from electricity to natural gas leads to greater percentage savings in both 

energy costs and carbon emissions than the percentage savings in energy consumption.

Table 49-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2004 2007 LEC

Energy Use -9.9 -12.6 -25.7

Energy Cost -12.2 -14.2 -28.8

Carbon Emissions -16.6 -17.2 -34.6

Life-Cycle Cost -1.6 -1.9 -2.2

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in West Virginia averaged 0.5 million m

2 (5.2 million ft2

) of new floor area annually. 

Table 49-2 shows that based on its average new construction, the state would realize 

reductions in energy consumption in GWh, energy costs in present value dollars (PV$), 

energy-related carbon emissions in metric tCO2e, and life-cycle costs in present value 

dollars (PV$) from adopting the ASHRAE 90.1-2004, ASHRAE 90.1-2007, or LEC design 

as its state energy code over a 10-year study period for one year’s worth of new 

construction.

Table 49-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2004 2007 LEC

Energy Use GWh -58.7 -96.4 -177.2

Energy Cost PV$Million -$3.6 -$5.0 -$9.7

Carbon Emissions 1000 Metric tCO2e -68 -79 -161

Life-Cycle Cost PV$Million -$5.6 -$7.3 -$7.1
102

49.2 The Bottom Line

West Virginia could benefit from the adoption of a newer edition of ASHRAE 90.1 as its 

state energy code. Adopting ASHRAE 90.1-2007 leads to greater reductions in energy 

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

adopting ASHRAE 90.1-2004. If West Virginia were to adopt the LEC design as its state 

energy code, which is based on the energy efficiency requirements defined in ASHRAE 

189.1-2009, it could realize even greater savings in energy consumption, energy costs, 

and energy-related carbon emission relative to ASHRAE 90.1-2007, but at slightly lower 

life-cycle cost savings. These are conservative estimates because a building’s lifetime is 

significantly longer than the 10-year study period length. As the study period increases,

operating energy becomes a more significant driver of overall costs, which will drive lifecycle cost savings up. Given a longer study period, the LEC design may become the most 

cost-effective building design alternative.
103

50 Wisconsin

Wisconsin has adopted ASHRAE 90.1-2007 as its state energy code for commercial 

buildings, is located in the East North Central Census Region, and spans two climate 

zones (Zone 6A and Zone 7).

50.1 Statewide Results

Table 50-1 shows that, on average, adopting the LEC design leads to percentage 

reductions in energy consumption (12.6 %), energy costs (16.6 %), energy-related carbon 

emissions (16.9 %), and life-cycle costs (0.7 %). Assuming natural gas is used for heating 

in Wisconsin, the adoption of the LEC design leads to a shift in energy consumption from 

electricity to natural gas. In Wisconsin, natural gas is cheaper on a per-unit of energy 

basis and leads to less CO2e emissions per unit of energy consumed. As a result, the shift 

in consumption from electricity to natural gas leads to greater percentage savings in both 

energy costs and carbon emissions than the percentage savings in energy consumption.

Table 50-1 Average Percentage Change from Adoption of the LEC Design – 10-Yr 

Study Period

Metric LEC

Energy Use -12.6

Energy Cost -16.6

Carbon Emissions -16.9

Life-Cycle Cost -0.7

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Wisconsin averaged 2.4 million m2 (25.7 million ft2

) of new floor area annually. Table 

50-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption (491 GWh), energy costs ($33 million), energy-related carbon 

emissions (384 000 metric tons), and life-cycle costs ($15 million) from adopting the 

ASHRAE 90.1-2004, ASHRAE 90.1-2007, or LEC design as its state energy code over a 

10-year study period for one year’s worth of new construction.

Table 50-2 Total Change from Adoption of the LEC Design – 10-Yr Study Period

Metric Unit LEC

Energy Use GWh -491.0

Energy Cost PV$Million -$33.2

Carbon Emissions 1000 Metric tCO2e -384

Life-Cycle Cost PV$Million -$14.9
104

50.2 The Bottom Line

Wisconsin could benefit from the adoption of the LEC design as its state energy code, 

which is based on the energy efficiency requirements defined in ASHRAE 189.1-2009. 

Adoption of the LEC design leads to reduction in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs. These are conservative estimates 

because a building’s lifetime is significantly longer than the 10-year study period length. 

As the study period increases, operating energy becomes a more significant driver of 

overall costs, which will drive life-cycle cost savings up.
105

51 Wyoming

Wyoming is located in the Mountain Census Division and spans three climate zones 

(Zone 5B, Zone 6B, and Zone 7). The state does not have a commercial building energy 

code and, for this analysis, is assumed to build to the current minimum industry practices 

represented by ASHRAE 90.1-1999 requirements.

51.1 Statewide Results

Table 51-1 shows that, on average, adopting newer editions of ASHRAE 90.1 or the LEC 

design lead to percentage reductions in energy consumption up to 23.8 %, energy costs

up to 31.7 %, and energy-related carbon emissions up to 31.6 %. Additionally, adopting

ASHRAE 90.1-2007 or the LEC design leads to percentage reductions in life-cycle costs

up to 0.5 %.

Table 51-1 Average Percentage Change from Adoption of Newer Standards – 10-Yr 

Study Period

Metric 2001 2004 2007 LEC

Energy Use -0.9 -7.6 -11.7 -23.8

Energy Cost -1.1 -15.7 -17.4 -31.7

Carbon Emissions -1.1 -15.6 -17.3 -31.6

Life-Cycle Cost 2.2 0.1 -0.3 -0.5

Assuming natural gas is used for heating in Wyoming, the adoption of newer editions of 

ASHRAE 90.1 leads to a shift in energy consumption from electricity to natural gas. In 

Wyoming, natural gas is cheaper on a per-unit of energy basis and leads to less CO2e 

emissions per unit of energy consumed. As a result, the shift in consumption from 

electricity to natural gas leads to greater percentage savings in both energy costs and 

carbon emissions than the percentage savings in energy consumption.

Between 2003 and 2007, commercial and non-low-rise residential building construction 

in Wyoming averaged 0.2 million m2 (2.5 million ft2

) of new floor area annually. Table 

51-2 shows that based on its average new construction, the state would realize reductions 

in energy consumption in GWh, energy costs in present value dollars (PV$), and 

energy-related carbon emissions in metric tCO2e from adopting any edition of ASHRAE 

90.1 or the LEC design as its state energy code over a 10-year study period for one year’s 

worth of new construction. Additionally, the savings from the adoption of ASHRAE 

90.1-2007 and the LEC design are realized while decreasing life-cycle costs in present 

value dollars (PV$).
106

Table 51-2 Total Change from Adoption of Newer Standards – 10-Yr Study Period

Metric Unit 2001 2004 2007 LEC

Energy Use GWh -2.7 -22.0 -34.9 -76.6

Energy Cost PV$Million -$0.2 -$2.4 -$2.6 -$5.3

Carbon Emissions 1000 Metric tCO2e -2 -24 -27 -53

Life-Cycle Cost PV$Million $3.9 $0.2 -$0.5 -$0.7

51.2 The Bottom Line

Wyoming could benefit from the adoption of a state energy code, particularly by taking 

an aggressive approach at increasing new building energy efficiency requirements. 

Adopting the LEC design, which is based on the energy efficiency requirements defined 

in ASHRAE 189.1-2009, leads to greater reductions in energy consumption, energy costs, 

energy-related carbon emissions, and life-cycle costs than adopting any edition of 

ASHRAE 90.1. If Wyoming were to adopt a state energy code similar to the majority of 

states in the U.S. (ASHRAE 90.1-2007), it could still realize savings, although much 

smaller, in energy consumption, energy costs, and energy-related carbon emission while 

decreasing life-cycle costs. These are conservative estimates because a building’s lifetime 

is significantly longer than the 10-year study period length. As the study period increases,

operating energy becomes a more significant driver of overall costs, which will drive lifecycle cost savings up.
107

52 Limitations and Future Research

The analysis in this study is limited in scope and would be strengthened by including 

sensitivity analysis, expanding the BIRDS database and metrics, and enabling public 

access to all the results.

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 BIRDS database should be 

expanded to include alternative fuel source options, such as heating oil use in the New 

England area or electric heating in the South. 

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 new construction 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 high-rise buildings 

are not 100 % vertical fenestration. For this reason, the results should be considered as 

orders of magnitude instead of precise estimates. Future research should include 

additional prototypes in the database, such as the Department of Energy Commercial 

Reference Buildings. Additionally, since existing buildings account for nearly the entire 

building stock, prototypes for energy retrofits to 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 the BIRDS database could be improved.

The analysis in this study ignores the impacts that occupant behavior, such as 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 heating 

and cooling 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. Also, occupants may have different preferences 

for indoor conditions, such as higher or lower temperature setpoints, which will impact 
108

the energy consumption of the building. Future research should consider the impact the 

assumed occupant behaviors 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-to-use 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 increase the impact of this work. This study would 

apply 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 eleven 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, maintenance, repair, and 

replacement of building components, 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.
109

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