●

A national laboratory of the U.S. Department of Energy 

Office of Energy Efficiency & Renewable Energy 

National Renewable Energy Laboratory 

Innovation for Our Energy Future 

A New Market Paradigm Technical Report 

NREL/TP-550-38304-02 for Zero-Energy Homes: December 2006 

The Comparative San Diego 

Case Study 

Volume 2 of 2 (Appendixes) 

B.C. Farhar 

National Renewable Energy Laboratory 

T.C. Coburn 

Abilene Christian University 

NREL is operated by Midwest Research Institute Battelle Contract No. DE-AC36-99-GO10337 

Link to Volume 1: Report
A New Market Paradigm 

for Zero-Energy Homes: 

The Comparative San Diego 

Case Study 

Volume 2 of 2 (Appendixes)

B.C. Farhar 

National Renewable Energy Laboratory 

T.C. Coburn 

Abilene Christian University

Prepared under Task No. ZB03.3003 

Technical Report

NREL/TP-550-38304-02

December 2006 

National Renewable Energy Laboratory

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303-275-3000 • www.nrel.gov

Operated for the U.S. Department of Energy

Office of Energy Efficiency and Renewable Energy

by Midwest Research Institute • Battelle 

Contract No. DE-AC36-99-GO10337
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Contents 

(Appendixes) 

Appendix Page 

Note: The letters “I” and “O” are not used in these appendix designations. 

Chapter 1 

Appendix A. New Developments in San Diego .............................. A-1

Chapter 2 

Appendix B. Questionnaire for SheaHomes PV Respondents: Household Questionnaire 

on Purchasing and Owning a High-Performance Home with a 

Solar PV System ........................................... B-1

Appendix C. Questionnaire for SheaHomes Main Respondents: Household Questionnaire 

on Purchasing and Owning a High-Performance Home ............. C-1

Appendix D. Questionnaire for SheaHomes Early Respondents: Household Questionnaire 

on Purchasing and Owning a Highly Energy-Efficient Home ......... D-1

Appendix E. Questionnaire for Comparison Respondents: Household Questionnaire 

on Purchasing and Owning a Recently Built Home ................ E-1

Chapter 6 

Appendix F. Base n’s, Means, Standard Deviations, and Coefficients of Variation 

for Scaled Responses ........................................ F-1

Appendix G. Respondent Characteristics: Demographics, Values and Lifestyles, 

and Other Variables ......................................... G-1

Chapter 17 

Appendix H. Detailed Factor Analysis Results ............................... H-1

Appendix H1. Factors by Demographics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H1-1

Chapter 20 

Appendix J. Scatter Diagrams of Average Monthly Electricity Consumption by

Average Monthly Electricity Cost for All Homes in the Study ........ J-1

Appendix K. Scatter Diagrams of Average Monthly Gas Consumption by Average 

Monthly Gas Cost for All Homes in the Study .................... K-1

iii 
Appendixes 

(continued)

Page

Appendix L. Line Graphs for Month-to-Month Consumption of Electricity for 

Individual Homes in the Study .............................. L-1

Appendix M. Line Graphs for Month-to-Month Consumption of Gas for 

Appendix S. Descriptive Statistics on Total and Average Electricity Consumption and Total 

and Average Gas Consumption with and without Selected Equipment, by

Appendix U. Descriptive Statistics on Average Monthly Electricity Cost, Average Monthly

Gas Cost, and Average Monthly Utility Bills with and without Selected 

Individual Homes in the Study ....................................... M-1

Appendix N. Descriptive Statistics, 12-Month Utility Consumption, and Cost Data ......... N-1

Appendix P. Histograms of 12-Month Utility Data for All Homes Combined ............. P-1

Appendix Q. Histograms of 12-Month Utility Data for SheaHomes and Comparison Homes . Q-1

Appendix R. Histograms of 12-Month Utility Data for PV and SEE Homes ............... R-1

Categories of Homes (12-Month Data) ................................ S-1

Appendix T. Histograms of 12-Month Utility Data for Comparison and SEE Homes ....... T-1

Equipment, by Categories of Homes (12-Month Data) ..................... U-1

Chapter 21 

Appendix V. Scatter Diagrams of Average Monthly Electricity Cost Consumption by Average

Monthly Cost for All Homes in the Study ........................... V-1

Appendix W. Electricity and Gas Consumption for 1.2-kW and 2.4-kW Solar PV Systems in the

SheaHomes Communities ........................................... W-1

iv 
Appendix A

New Developments in San Diego

Cited in Chapter 1

A-1
Appendix A

New Developments in San Diego

The City of San Diego has, as part of its sustainability initiative, recently started an Expedite 

program to accelerate the permitting process for building homes with PV systems. The city had 

adopted a broad goal of achieving 50 MW of self-generated renewable electricity within the next 

5 years. As a tangible step to encourage builders to include energy efficiency and PV in their 

new homes, the city’s Expedite program, in essence, puts builders who plan to include solar PV 

as a standard feature in their homes at the front of the line to receive building permits. 

Usually, the permitting process for an undeveloped piece of land takes approximately 24 months. 

The city cuts that time down to 6 to 9 months if the PV system provides 50% of the estimated 

electricity needs of the home, based on Title 24’s estimate of electricity use per square foot. 

Although it cost the city nothing to implement, the Expedite program results in a small revenue 

stream because the city charges a $500 fee for an Expedite application. 

The builder benefits from the program because builders pay finance charges on loans for property 

they own and are waiting for a building permit to develop. These charges vary, of course, but can 

often range from $2,000 to $4,000 a month. If it takes 24 months to obtain a building permit, the 

finance charges at the high end of this example could total $96,000. If the Expedite program 

results in a building permit in only 6 months, the builder would pay only $24,000 instead of 

$96,000 in finance charges, thus saving $72,000. In addition, the San Diego builder can recoup 

half of the installed system cost because of the CEC rebates; therefore, the costs that need to be 

passed along to the homebuyer are only 50% of the actual installed PV system cost. This price 

premium ranges from $8,000 to $10,000 per home. Because housing demand in San Diego is 

high, buyers readily pay this premium; in fact, one builder’s homes are 100% pre-sold. The 

company believes that PV may add value to its marketing campaign. It appears that the worstcase scenario for builders is that PV does not interfere with their sales (and may increase the 

dollar value of sales) while it saves them appreciably in finance charges. 

Of course, with houses in the Expedite program, the PV home buyers do not have the option of 

selecting a PV system for their homes; it comes as a standard feature. Buyers are always free to 

purchase a conventional rather than a ZEH home. But, all other things being equal, the buyers 

benefit from purchasing a home with PV as a standard feature because (1) they don’t have to 

decide about an unfamiliar but expensive technology, (2) they should enjoy significant savings 

on their electricity bills for at least 20 years, (3) they will probably realize appreciated resale 

value for their homes when they sell, and (4) they can roll the cost into their home mortgage, the 

monthly incremental cost of which should be less than their electricity savings. 

A-2
Appendix B

Questionnaire for SheaHomes PV Respondents:

Household Questionnaire on Purchasing and Owning a

High-Performance Home with a Solar PV System

Cited in Chapter 2 

B-1















Appendix C

Questionnaire for SheaHomes Main Respondents:

Household Questionnaire on Purchasing and

Owning a High-Performance Home

Cited in Chapter 2 

C-1













Appendix D

Questionnaire for SheaHomes Early Respondents:

Household Questionnaire on Purchasing and

Owning a Highly Energy-Efficient Home

Cited in Chapter 2 

D-1













Appendix E 

Questionnaire for Comparison Respondents: 

Household Questionnaire on Purchasing 

and Owning a Recently Built Home 

Cited in Chapter 2 

D-1

-










Appendix F 

Base n’s, Means, Standard Deviations,

and Coefficients of Variation 

for Scaled Responses

Cited in Chapter 6 

F-1
Appendix F. Base n’s, Means, Standard Deviations, 

and Coefficients of Variation 

Descriptive Statistics 

This appendix presents descriptive statistics on the responses to all scaled questions contained in 

the questionnaires. For each question (or variable), Appendix F presents the number of 

respondents, an average rating (average score assigned by all respondents), the standard deviation 

of all responses, and the coefficient of variation (CV) relating the standard deviation (variation in 

ratings or scores) to the corresponding average value. 

The CV, stated in percent, is an index ranging in size from 0 to 100 that indicates the variability 

in a specific set of responses above and beyond the average response value. High CV values 

indicate excessive variation. Note, however, that because the survey responses constitute ordinal 

measurements (where a high average value is considered “good” and a low averaged value is 

considered “bad”), the CV can only be regarded as a relative measure, and care must be exercised 

when comparing different CV values. 

This appendix contains several tables that present descriptive statistics on the responses to scaled 

questions or items included in the homeowner questionnaires. A total of 149 such items, 

representing several broad topical areas (such as homeowner satisfaction with the new home), are 

encompassed by these tables. Each table gives the number of responses (generally, all 

homeowners combined) to each of the items in question, along with the associated mean rating 

(the average score assigned by all respondents), the standard deviation of all responses, and the 

coefficient of variation (CV). The CV is computed by taking the ratio of the standard deviation to 

the mean and multiplying by 100. Hence, its values range from 0 to 100 (or more), stated in 

percent. Because of the way it is computed, the CV carries information about both the mean 

(center value) and the standard deviation (spread or dispersion), expressing the variability in 

responses above and beyond the average response. The CV can be an extremely useful tool for 

comparing the variation among items since it is reported only in terms of percent and is not 

dependent on the particular scale of each item. However, care must be exercised when 

interpreting the CV of each item outright, since the scales are discrete ordinal measurements. 

The CV values reported here suggest that responses to the individual scaled questions or items in 

the homeowner surveys are low to moderately high. CV values close to 0 are desired, whereas 

the ones reported here range from about 12% to about 44%. The following table shows the 

percentage distribution of CV values reported for all 149 items. 

2
Table F-1. Percentage Distribution of CV Values Associated 

with Questionnaire Items Reported on Likert Scales 

Size Interval for 

CV Values 

Number of 

Occurrences 

Percent of 

Occurrences 

<10 0 – 

10.1!15 9 6.0 

15.1!20 35 23.5 

20.1!25 31 20.8 

25.1!30 35 23.5 

30.1!35 19 12.8 

35.1!40 14 9.4 

>40 5 3.4 

Total 149 100* 

*Does not add to 100 because of rounding. 

The six items with the lowest CV values are: 

• Importance of safe and secure feeling (11.96) 

• Satisfaction with home’s location (12.18) 

• Satisfaction with investment potential of home (12.54) 

• Purchase decision: quality of neighborhood/community (13.17) 

• NEP: preserve environment for future generations (13.80) 

• Purchase decision: overall home value (14.07) 

Interestingly, these items also have some of the highest mean values (on 1-5 scales) among those 

reported. The high mean values suggest these items are among those having greatest practical 

significance for homeowners. The corresponding low CV values suggest that homeowners are 

fairly consistent in their responses to these items. 

The six items with the highest CV values are: 

• Informed about energy efficiency and solar energy when looking for home (43.66) 

• Concern about San Diego’s electricity costs (43.11) 

• Utilities: electric rates have come down since we moved in (42.69) 

• PV barrier: thought it would negatively affect resale value (40.10) 

• PV barrier: didn’t know where it would go on the roof (40.00) 

• PV barrier: energy is not that important (39.44) 

The relatively high CV values associated with these items suggests homeowners are rather 

uncertain about them. Interestingly, all of the items reflect the absence of information or 

knowledge to a certain degree. 

3
Table F-2. Descriptive Statistics on Items Pertaining to the 

Importance of the Factor in the Home Purchase Decision

Item 

Base

 n1 Mean2 

Standard 

Deviation 

Coefficient of 

Variation3 

Purchase decision: close to work 225 3.97 1.040 26.20 

Purchase decision: near to freeway 226 4.06 0.917 22.59 

Purchase decision: near services 226 3.97 0.819 20.63 

Purchase decision: great view 224 3.70 1.180 31.89 

Purchase decision: safe and secure feeling 226 4.69 0.561 11.96 

Purchase decision: quality of schools 226 4.05 1.250 30.86 

Purchase decision: knows area 225 3.75 1.070 28.53 

Purchase decision: close to friends 223 3.25 1.250 38.46 

Purchase decision: close to parks/playgrounds 223 3.09 1.110 35.92 

Purchase decision: desirable area 225 4.39 0.706 16.08 

Purchase decision: overall home value 223 4.52 0.636 14.07 

Purchase decision: investment potential 225 4.35 0.777 17.86 

Purchase decision: mello roos taxes 226 4.49 0.807 17.97 

Purchase decision: discount or incentive 217 3.39 1.210 35.69 

Purchase decision: builder reputation 224 3.87 0.897 23.18 

Purchase decision: helpfulness of staff 226 3.76 0.969 25.77 

Purchase decision: quality of neighborhood/ 

community 226 4.57 0.602 13.17 

Purchase decision: exterior design 226 4.05 0.756 18.67 

4
Table F-2. Descriptive Statistics on Items Pertaining to the 

Importance of the Factor in the Home Purchase Decision 

(continued) 

Item 

Base

 n1 Mean2 

Standard 

Deviation 

Coefficient of 

Variation3 

Purchase decision: feeling of community spirit 224 3.66 1.020 27.87 

Purchase decision: availability of very energyefficient home 226 3.79 0.893 23.56 

Purchase decision: availability of solar water heating 

(PV, M, I/e) 172 3.49 1.030 29.51 

Purchase decision: availability of solar PV (PV, M) 150 3.34 1.050 31.44 

Purchase decision: the package of energy features 

together (PV, M, I/e) 169 3.56 0.950 26.69 

Purchase decision: other 20 4.20 1.240 29.52 

1

All SheaHomes and comparison homes respondents combined 

2

Response scale of 1 to 5 indicating level of importance, with 5 being very important 

3

Coefficient of variation=100*(Standard Deviation/Mean) 

5
Table F-3. Descriptive Statistics on Items Pertaining to the 

Importance of the Home Feature in the Home Purchase Decision

Item 

Base 

n1 Mean2 

Standard 

Deviation 

Coefficient of 

Variation3 

Purchase feature: architectural design 227 4.11 0.801 19.49 

Purchase feature: size/square footage 228 4.34 0.627 14.43 

Purchase feature: floor plan/layout 227 4.53 0.673 14.86 

Purchase feature: number of bedrooms 227 4.16 0.707 16.70 

Purchase feature: three-car garage 227 3.93 1.060 26.97 

Purchase feature: granite counter tops as standard 

feature 225 3.59 1.130 31.48 

Purchase feature: large closets/pantries 226 3.90 0.889 22.79 

Purchase feature: single-story option 217 2.44 1.400 26.48 

Purchase feature: lot size/yard 228 3.89 1.030 26.48 

Purchase feature: quality of construction 228 4.45 0.691 15.53 

Purchase feature: spaciousness/openness 227 4.38 0.683 15.59 

Purchase feature: quality or sense of light 227 4.24 0.734 17.31 

Purchase feature: many amenities included as 

standard features 226 4.01 0.822 20.50 

Purchase feature: availability of many options 227 3.79 0.920 24.27 

Purchase feature: quiet area 222 4.11 0.872 21.22 

Purchase feature: first other response 19 4.53 0.964 21.28 

Purchase feature: second other response 6 4.17 1.600 38.37 

1

All SheaHomes and comparison homes respondents combined 

2

Response scale of 1 to 5 indicating level of importance, with 5 being very important 

3

Coefficient of variation=100*(Standard deviation/Mean) 

6
Table F-4. Descriptive Statistics on Items Pertaining to Satisfaction with the New Home 

Item 

Base 

n1 Mean2 

Standard 

Deviation 

Coefficient of 

Variation3 

Satisfaction with staff providing information to help 

with purchase decision 229 7.65 2.170 28.37 

Satisfaction with staff providing information on 

energy efficiency and solar features (PV, M, I/e) 174 7.24 2.180 30.11 

Satisfaction with staff responding to problems after 

moved in 229 7.09 2.630 37.09 

Informed about energy efficiency and solar energy 

when looking for home 227 5.52 2.410 43.66 

Informed about energy efficiency and solar energy 

now (PV, M, I/e) 174 7.33 1.930 26.33 

Satisfaction with home’s location 225 4.64 0.565 12.18 

Satisfaction with investment potential of home 224 4.64 0.582 12.54 

Satisfaction with builder reputation 226 3.72 1.110 29.84 

Satisfaction with size/square footage 226 4.35 0.746 17.15 

Satisfaction with layout/floor plan 225 4.10 0.881 21.49 

Satisfaction with storage space 226 3.76 0.970 25.80 

Satisfaction with lot size and yard 226 3.99 0.877 21.98 

Satisfaction with quality of construction 225 3.54 1.050 29.66 

Satisfaction with the package of energy features 

(PV, M, I/e) 172 3.92 0.872 22.24 

Satisfaction with net metering (PV respondents) 66 3.76 0.993 26.41 

Satisfaction with number of thermostats 223 3.43 1.160 33.82 

1

All SheaHomes and comparison homes respondents combined 

2

Response scale of 1 to 5 indicating level of satisfaction, with 5 being very satisfied 

3

Coefficient of variation=100*(Standard deviation/Mean) 

7
Table F-5. Descriptive Statistics on Items Pertaining to Homeowner Expectations about Utility Bills 

and Their Opinions about Buying Future Homes with Energy Efficiency Features 

Item 

Base 

n Mean2 

Standard 

Deviation 

Coefficient of 

Variation2 

Utility bills lower with solar water heating (Main 

owners, Ineligible/Early owners) 97 3.37 0.928 27.54 

Gas bills lower than they would have been (PV 

owners) 70 3.36 1.170 34.82 

Electric bills lower than they would have been (PV 

owners) 70 3.61 1.280 35.46 

Utility bills met or exceeded expectations1

 1721 3.15 0.983 31.21 

Would buy same home again1 2261 3.93 0.902 22.95 

Will buy energy efficiency in new home1 2261 4.12 0.785 19.05 

Will buy solar water heating in new home1 2271 3.77 0.893 23.69 

Will buy solar PV in new home1 2231 3.69 0.910 24.66 

1

All SheaHomes and comparison homes respondents combined 

2

Likert scale where 1=strongly disagree and 5=strongly agree 

2

Coefficient of variation=100*(Standard deviation/Mean) 

8
Table F-6. Descriptive Statistics on Items Pertaining to Importance of PV Attributes1 

Item 

Base 

n1 Mean2 

Standard 

Deviation 

Coefficient of 

Variation3 

PV attributes: amount of electricity produced 70 4.24 0.892 21.04 

PV attributes: finance through home mortgage 70 3.49 1.190 34.10 

PV attributes: owning the solar PV system outright 70 3.43 1.110 32.36 

PV attributes: net metering 68 3.59 1.030 28.69 

PV attributes: digital display showing electricity 

production and consumption 69 3.88 0.867 22.35 

PV attributes: length of warranty 70 4.04 0.806 19.95 

PV attributes: ease of maintenance 70 4.07 0.822 20.20 

PV attributes: attractiveness/unobtrusiveness of the 

system 70 3.91 1.030 26.34 

PV attributes: upgrade capability 70 3.64 1.040 28.57 

PV attributes: other 1 5.00 0.000 0.00 

1

PV homeowners only 

2

Response scale of 1 to 5 indicating level of importance, with 5 being very important 

3

Coefficient of variation=100*(Standard deviation/Mean) 

Table F-7. Descriptive Statistics on Items Pertaining to Homeowner Perceptions of 

Comfort and Energy Efficiency of the Home 

Item 

Base 

n1 Mean 

Standard 

Deviation 

Coefficient of 

Variation4 

Perceived comfort of home overall 226 8.332 1.39 16.69 

Perceived energy efficiency of home overall 224 7.113 1.79 25.18 

1

All SheaHomes and comparison homes respondents combined.

2

Response scale of 1 to 10 indicating level of comfort, with 10 being very comfortable.

3

Response scale of 1 to 10 indicating level of energy efficiency, with 10 being very efficient. 4

Coefficient of variation=100*(Standard deviation/Mean)

9
Table F-8. Descriptive Statistics on Items Pertaining to Perceived Benefits of PV Ownership 

Item 

Base 

n1 Mean2 

Standard 

Deviation 

Coefficient of 

Variation3 

Perceived benefits: reduces electricity bills 71 4.17 0.862 20.67 

Perceived benefits: sell excess electricity back to 

utility 71 3.72 1.040 27.96 

Perceived benefits: provides free electricity once 

system is paid for 69 3.43 1.080 31.49 

Perceived benefits: increases home’s resale value 71 4.03 0.717 17.79 

Perceived benefits: protects against rising electricity 

costs 71 3.51 1.040 29.63 

Perceived benefits: increases self-sufficiency 70 3.66 0.915 25.00 

Perceived benefits: feels good to have it 71 3.79 0.877 23.14 

Perceived benefits: technologically innovative 71 3.62 0.763 21.08 

Perceived benefits: helps the environment 71 3.97 0.696 17.53 

Perceived benefits: increases our awareness of 

household energy use 69 3.91 0.818 20.92 

Perceived benefits: conserves natural resources 71 4.18 0.946 22.63 

Perceived benefits: helps improve air quality in area 71 3.86 0.833 21.58 

Perceived benefits: benefits future generations 71 3.93 0.762 19.39 

Perceived benefits: helps reduce global warming 71 3.59 0.994 27.69 

Perceived benefits: helps San Diego’s economy 69 3.64 0.891 24.48 

Perceived benefits: first other response 3 3.00 0.000 0.00 

Perceived benefits: second other response 4 3.00 0.000 0.00 

1

PV homeowners only 

2

Likert scale of 1 to 5 where 1=strongly disagree and 5=strongly agree 

3

Coefficient of variation=100*(Standard deviation/Mean) 

10
Table F-9. Descriptive Statistics on Items Pertaining to

Barriers to Purchase of Homes with Solar PV

Item 

Base 

n1 Mean2 

Standard 

Deviation 

Coefficient of 

Variation3 

PV barrier: energy is not that important 38 1.95 0.769 39.44 

PV barrier: it was too expensive 38 4.24 0.714 16.84 

PV barrier: wanted other options instead 38 3.13 0.777 24.82 

PV barrier: didn’t know enough to evaluate system 37 2.84 0.928 32.68 

PV barrier: didn’t know where it would go on the roof 36 2.50 1.000 40.00 

PV barrier: payback would be too long 37 3.84 0.986 25.68 

PV barrier: thought homeowners insurance premium 

would increase 34 2.56 0.860 33.59 

PV barrier: thought property taxes would increase 35 2.80 0.933 33.32 

PV barrier: unsure about the reliability of system 36 3.22 1.050 32.61 

PV barrier: thought it would negatively affect resale 

value 36 2.06 0.826 40.10 

PV barrier: could become outdated technologically 37 2.81 1.020 36.30 

PV barrier: concerned about maintenance issues 35 3.34 1.080 32.34 

PV barrier: did not like how the system looks 35 2.46 0.886 36.02 

PV barrier: first other response 2 5.00 0.000 0.00 

1

Main homeowners only.

2

Likert scale of 1 to 5 where 1=strongly disagree and 5=strongly agree.

3

Coefficient of variation=100*(Standard deviation/Mean)

11
Table F-10. Descriptive Statistics on Items Pertaining to Satisfaction with PV System 

Item 

Base 

n1 Mean2 

Standard 

Deviation 

Coefficient of 

Variation2 

How happy with PV system 68 7.66 2.05 26.76 

1

PV homeowners only 

2

Response scale of 1 to 10 indicating level of satisfaction, with 10 being very satisfied 

2

Coefficient of variation=100*(Standard deviation/Mean) 

Table F-11. Descriptive Statistics on Items Pertaining to Utility Costs and Operational Aspects 

Item 

Base 

n Mean3 

Standard 

Deviation 

Coefficient of 

Variation4 

Utilities: electricity rates have come down since we 

moved in 2231 2.53 1.080 42.69 

Utilities: power outages are a problem in San Diego 2231 2.65 1.000 37.74 

Utilities: utility sends clear and beneficial 

information about net metering 672 3.10 0.855 27.58 

Utilities: utility was helpful in connecting PV system 

with grid 682 3.13 0.790 25.24 

Utilities: pleased with billing process for electricity 2211 3.11 0.879 28.26 

1

All SheaHomes and comparison home respondents combined 

2

PV homeowners only 

3

Likert scale of 1 to 5 where 1=strongly disagree and 5=strongly agree 

4

Coefficient of variation=100*(Standard deviation/Mean) 

Table F-12. Descriptive Statistics on Items Pertaining to the Desirability and 

Cost Effectiveness of Solar PV and Solar Water Heating Systems 

Item 

Base 

n1 Mean2 

Standard 

Deviation 

Coefficient of 

Variation3 

Solar PV systems are a desirable innovation for new 

homes 222 3.97 0.790 19.90 

Solar water heating systems are a desirable 

innovation for new homes 223 4.04 0.787 19.48 

Solar PV systems are cost effective 223 3.50 0.816 23.31 

Solar water heating systems are cost effective 224 3.65 0.749 20.52 

1

All SheaHomes and comparison homes respondents combined 

2

Likert scale of 1 to 5 where 1=strongly disagree and 5=strongly agree 

3

Coefficient of variation=100*(Standard deviation/Mean) 

12 
Table F-13. Descriptive Statistics on Items Pertaining to

Energy-Related Behaviors of Homeowners

Item 

Base 

n1 Mean2 

Standard 

Deviation 

Coefficient of 

Variation3 

Behavior: tend to be thrifty 223 3.50 0.939 26.83 

Behavior: regularly recycle paper, plastic, or cans 227 4.21 0.886 21.05 

Behavior: in winter set thermostat 70 or lower 226 3.98 1.070 26.88 

Behavior: in summer set thermostat 75 or higher 225 3.65 1.180 32.33 

Behavior: when away modify thermostat settings 225 4.33 0.855 19.75 

Behavior: turn off lights 226 4.45 0.693 15.57 

Behavior: turn off computers 225 3.81 1.330 34.91 

Behavior: conserve water 224 3.94 0.938 23.81 

Behavior: more energy conscious than we used to be 223 4.04 0.939 23.24 

Behavior: use air conditioning less than in previous 

home 221 3.43 1.260 36.73 

Behavior: drive fuel-efficient vehicles 222 3.09 1.170 37.86 

Behavior: practice xeriscaping 194 2.79 0.834 29.89 

1

All SheaHomes and comparison homes respondents combined 

2

Likert scale of 1 to 5 where 1=strongly disagree and 5=strongly agree 

3

Coefficient of variation=100*(Standard deviation/Mean) 

13
Table F-14. Descriptive Statistics on Items Pertaining to Energy-Related Policy Preferences 

Item 

Base 

n1 Mean2 

Standard 

Deviation 

Coefficient of 

Variation3 

Policy: utility companies should give rebates for 

energy-efficient appliances 222 4.35 0.745 17.13 

Policy: federal income has credits given to buyers of 

energy-efficient homes 222 4.33 0.816 18.85 

Policy: homes technically rated efficient should be 

given ENERGY STAR label 222 4.29 0.729 16.99 

Policy: California Energy Commission should give 

rebated for PV 222 4.32 0.807 18.68 

Policy: California Energy Commission should give 

rebates for SWH 222 4.27 0.829 19.41 

Policy: federal government should support research 

on ZEH 220 4.29 0.837 19.51 

Policy: builders should build energy-efficient homes 

if cost is less 221 4.43 0.682 15.40 

Policy: builders should build energy-efficient homes 

if more comfortable and look better 220 4.39 0.735 16.74 

Policy: energy package should be standard if cost 

effective 220 4.40 0.760 17.27 

Policy: affordable housing subsidies for PV 221 3.98 1.020 25.63 

Policy: affordable housing subsidies for SWH 221 3.94 1.010 25.63 

1

All SheaHomes and comparison homes respondents combined 

2

Likert scale of 1 to 5 where 1=strongly disagree and 5=strongly agree 

3

Coefficient of variation=100*(Standard deviation/Mean) 

14
Table F-15. Descriptive Statistics on Items Pertaining to the New Environmental Paradigm 

Item 

Base 

n1 Mean2 

Standard 

Deviation 

Coefficient of 

Variation3 

NEP: preserve environment for future generations 220 4.42 0.61 13.80 

NEP: threats to environment exaggerated 221 2.98 1.06 35.57 

NEP: federal regulations provide adequate protection 

for environment 220 2.95 0.96 32.51 

NEP: individuals need to take responsibility for 

environment 221 4.37 0.59 13.59 

NEP: household energy consumption not a major 

contributor to environmental problems 220 2.67 1.00 37.42 

1

All SheaHomes and comparison homes respondents combined 

2

Likert scale of 1 to 5 where 1=strongly disagree and 5=strongly agree 

3

Coefficient of variation=100*(Standard deviation/Mean) 

Table F-16. Descriptive Statistics on Items Pertaining to 

Early Adopter Characteristics and Attitudes toward the Environment 

Item 

Base 

n1 Mean2 

Standard 

Deviation 

Coefficient of 

Variation3 

Like to be as independent as possible 221 4.22 0.791 18.74 

Like to experience with new ways of doing things 221 3.88 0.768 19.79 

Seen as leader in work, social, or volunteer 219 3.85 0.766 19.90 

Buy environmentally friendly even if costs more 221 3.42 0.803 23.48 

Willing to modify lifestyle to help environment 221 3.74 0.721 19.28 

Intrigued with new technology 220 4.09 0.792 19.36 

1

All SheaHomes and comparison homes respondents combined 

2

Likert scale of 1 to 5 where 1=strongly disagree and 5=strongly agree 

3

Coefficient of variation=100*(Standard deviation/Mean) 

15
Table F-17. Descriptive Statistics on Items Pertaining to

Concern about Electricity Cost in San Diego

Item 

Base 

n1 Mean 

Standard 

Deviation 

Coefficient of 

Variation3 

Concern about San Diego’s electricity costs 224 6.172 2.66 43.11 

1

All SheaHomes and comparison homes respondents combined 

2

Response scale of 1 to 10 indicating level of concern, with 10 being very concerned 

3

Coefficient of variation=100*(Standard deviation/Mean) 

16
Appendix G

Respondent Characteristics:

Demographics, Values and Lifestyles, and Other Variables

G-1
Appendix G.

Respondent Characteristics:

Demographics, Values and Lifestyles, and Other Variables

A number of items that pertained to respondent characteristics were included in the 

questionnaires. These included gender, age, marital status, household composition, household 

size, occupation, educational attainment, income, length of time the household plans to stay in 

the home, where households moved from, lifestyle and values, and equipment owned. Appendix 

G discusses the findings and presents the data tables on these respondent characteristics. 

Gender of Head of Household 

At the beginning of the questionnaire’s section on demographics, the instruction read: “If two 

people have completed the questionnaire together, please select one person as head of household 

for answering the questions [about yourself and your household].” 

In response to the questionnaire instructions, more households selected “male” than “female” to 

characterize the head of household, even though both partners may have been involved in 

completing the questionnaire. Among SheaHomes respondents, 55% are male and 45% are 

female heads-of-household. Among comparison homes, 57% are male and 43% are female 

heads-of-household (Table G-1). 

Age 

Home ownership is an adult characteristic. Virtually all respondents are older than 25 years of 

age. Among SheaHomes respondents, 43% are younger homeowners who are 25–39 years of age, 

the modal response. Among comparison respondents, the same age range is the modal response 

at 47%. Approximately one-third of SheaHomes respondents (32%) and 21% of comparison 

respondents are 40–49 years of age. Twenty-three percent of SheaHomes and 26% of comparison 

respondents are 50–64 years of age. Finally, a few of the SheaHomes (2%) and comparison (6%) 

respondents are 65 years of age or older. Thus, a majority (55%) of owners of SheaHomes are 

40–64 years of age; a plurality (47%) of comparison homeowners are in that same age range 

(Table G-2). 

Marital Status 

Most (93% of SheaHomes and 98% of comparison) respondents are married or in a committed 

relationship (Table G-3). 

2
Household Composition 

Of SheaHomes households, 68% are composed of adults and children, as do 71% of comparison 

households. Of SheaHomes households, 32% comprise adults only, as do 29% of comparison 

households (Table G-4). 

Number of Occupants in Household 

Respondents were asked, “In total, how many people live in your household?” Table G-5 shows 

that virtually all households have two or more occupants (only 3% of SheaHomes households are 

composed of a single person). Among SheaHomes households, 74% have three or more 

occupants; similarly 80% of comparison households have three or more occupants. The mean 

number of occupants for SheaHomes is 3.53 and for comparison homes it is somewhat, but not 

significantly, larger at 3.86. (A t-test resulted in p=.159.) 

Household Size and Household Composition Combined 

The trend toward somewhat larger households in the comparison community is borne out by the 

data in Table G-6, which shows that 30% have families with 5 or more persons, including adults 

and children, compared to 18% of SheaHomes. Approximately one-fourth of the SheaHomes 

households comprise one- or two-adult households compared with one-fifth of comparison 

households. However, these differences are not significant. 

Occupation 

Number of Occupations Reported 

Almost all of both categories of households report only one wage earner (Table G-7). 

First Occupation Reported 

As might be expected, most homeowners in the study communities are in professional, 

management, business, and scientific occupations. Table G-8 shows the details. 

Highest Level of Educational Attainment 

A large majority of both categories of homeowners have completed a Bachelor’s degree or higher 

(74% of SheaHomes and 81% of comparison respondents). Comparison respondents have a 

higher percentage of advanced educational achievement—Master’s degree or higher—(46%) 

than do SheaHomes respondents (37%) (Table G-9). 

3
Annual Household Income before Taxes 

Table G-10 presents detailed data on the income levels of the two respondent categories. A 

recoded summary of the data is presented in Table G-11 showing a significant difference in 

income between the categories. Whereas comparison households (76%) are significantly more 

likely than SheaHomes households (59%) to earn $100,000–$199,999 annually, SheaHomes 

households (19%) are significantly more likely than are comparison households (4%) to earn 

$200,000 or more annually. 

Length of Time the Household Plans to Stay in the New Home 

Respondents were asked: “About how long do you plan to stay in your home?” and asked to fill 

in the number of years, or indicate “Permanently” or “Don’t know” as alternative responses. The 

modal response for both categories of homeowners is “Don’t know” (for 46% of SheaHomes and 

40% of comparison households). One-third of SheaHomes and 23% of comparison respondents 

indicate that they plan to stay “Permanently.” Eight percent of SheaHomes and 11% of 

comparison respondents say they plan to stay in their new homes at least 10 years. The 

remainder—19% of SheaHomes and 28% of comparison respondents—indicate lengths of time 

of 1–9 years. Table G-12 summarizes the data. 

Where Respondent Moved From 

To learn whether most respondents moved to Scripps Highlands from the San Diego area, the 

questionnaire asked, “Which city and state did you move from?” As shown in Table G-13, most 

respondents in both categories came from the local area. However, more than one-fifth of 

comparison respondents came from a different area. To speculate, many of the SheaHomes 

buyers had seen the construction trailer at Scripps Highlands when the project started, and the 

probability of their doing so was greatly enhanced if they were local residents. 

Lifestyle and Values 

Based on prior research on the diffusion of innovations (Rogers 1995) and on opinions about 

renewable energy (Farhar and Coburn 2000), data were collected on several variables that were 

hypothesized to be favorably related to renewable energy. These included lifestyle and values 

(such as environmentalism and self-sufficiency) (Leonard-Barton 1978; Leonard-Barton and 

Rogers 1979) and innovativeness and opinion leadership (Rogers 1995). Tables G-14 through G19 show data on these variables. 

Regarding innovativeness, opinion leadership, and self-sufficiency, most respondents indicate 

they like to be as independent as possible so as not to rely on others to meet their needs (Table G14). Majorities of both categories of homeowners indicate they like to experiment with new ways 

of doing things (Table G-15), although 26% of SheaHomes and 37% of comparison respondents 

are neutral or disagree. Large majorities of around 80% of both homeowner categories agree that 

they are intrigued with new technology (Table G-16). Similarly, two-thirds of SheaHomes and 

77% of comparison respondents agree that they are seen as leaders in work, social life, or 

volunteer activities (Table G-17). 

4
Regarding environmentalism, two-thirds of both categories of respondents agree that they are 

willing to modify their lifestyles to help the environment (Table G-18). Forty-seven percent of 

SheaHomes respondents agree that they tend to buy environmentally friendly products even if 

these cost more, compared with 41% of comparison respondents. However, almost as many of 

the respondents in both categories (.42%) are neutral on this point (Table G-19). 

Equipment Owned 

To have a measure of energy-using equipment owned by the study families, the questionnaires 

asked about ownership of household appliances and amenities. Tables G-20 through G-28 

present the data by homeowner categories. The findings are summarized as follows: 

• Ceiling fans are owned by 65% of SheaHomes and 59% of comparison respondents (Table 

G-20). 

• Dual-zone heating/air-conditioning systems are owned by 64% of SheaHomes and 63% of 

comparison respondents (Table G-21). 

• Dimmer switches for lights are owned by 49% of SheaHomes and 47% of comparison 

respondents (Table G-22). 

• Compact fluorescent light bulbs (CFLs) are owned by 44% of SheaHomes and 53% of 

comparison respondents (Table G-23). 

• Two refrigerators are owned by 44% of SheaHomes and 29% of comparison respondents 

(Table G-24). This difference nears significance (P2=3.67; p=.055). 

• Hot tubs are owned by 19% of SheaHomes and 31% of comparison respondents (Table G25). This difference nears significance (P2=3.30; p=.068). 

• Pools are owned by 16% of SheaHomes and 26% of comparison respondents (Table G-26). 

• Standalone freezers are owned by 13% of SheaHomes and 18% of comparison respondents 

(Table G-27). 

• Hot water flow regulators are owned by 9% of SheaHomes and 28% of comparison 

respondents (Table G-28). This difference is significant (P2=12.069; p=.001). 

5
Table G-1. Gender of Head of Household 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Male 55 57 

Female 45 43

 Totals 100 100

 Base n* 165 53 

*“Base n” is used to refer to the total number of respondents answering a 

question; it is, therefore, the denominator used in calculating the percentages of 

responses in each category. 

Table G-2. Age of Head of Household 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

#24 years old –* 0 

25–39 years old 43 47 

40–49 years old 32 21 

50–64 years old 23 26 

$65 years old 2 6

 Totals 100 100

 Base n 171 53 

*#.06% 

Table G-3. Marital Status of Head of Household 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Married/in a committed relationship 93 98 

No longer married or never married 7 2

 Totals 100 100

 Base n 168 53 

6
Table G-4. Household Composition 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Adults only 32 29 

Adults and children 68 71

 Totals 100 100

 Base n 167 51 

Table G-5. Number of Occupants in Household 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

1 0 3

2 24 20 

3 22 20 

4 33 30 

5 12 20 

6 or more 7 10

 Totals 100 100

 Base n 167 50 

Table G-6. Household Size and Household Composition Combined 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Adults only, households with 2 or fewer persons 27 20 

Adults only, households with 3 or more persons 6 10 

Adults with children, households of 4 or fewer persons 49 40 

Adults with children, households with 5 or more persons 18 30

 Totals 100 100

 Base n 166 50 

7
Table G-7. Number of Occupations Reported 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

One 96 98 

Two 4 2

 Totals 100 100

 Base n 149 45 

Table G-8. First Occupation Reported 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Scientists, engineers, pilots, other professionals 34 24 

Management/self-employed 30 24 

Physicians, dentists, pharmacists, attorneys 8 17 

Marketing and sales 8 9 

Government (locals/state/federal) 8 2 

Investments and financial services 5 4 

Skilled trades, technicians, semi-professionals 4 13 

Retired 4 7

 Totals 100 100

 Base n 147 46 

8
Table G-9. Highest Level of Education Attained by Head of Household 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Elementary school through some high school S 2 

High school graduate or equivalent 3 2 

Some college but no degree 13 8 

Associate’s degree 2 6 

Trade or technical school certificate 3 2 

Bachelor’s degree 37 35 

Master’s degree 20 19 

Work beyond the Master’s but no additional degree 3 6 

Doctoral degree 14 21

 Totals 100 100

 Base n 168 532

Table G-10. Annual Household Income before Taxes 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

< $50,000 3 2 

$50,000–99,999 20 18 

$100,000–149,999 38 49 

$150,000–199,999 21 27 

$200,000–249,999 11 4 

$250,000 or more 8 S

 Totals 100 100

 Base n 156 45 

9
Table G-11. Annual Household Income before Taxes, Recoded Data 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

#$99,999 22 20 

$100,000–$199,999 59 76 

$$200,000 19 4

 Totals 100 100

 Base n 155 45 

P2=6.092; p=.048 

Table G-12. Length of Time Plan to Stay in Home 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

1–9 years 19 28 

$10 years 8 11 

Permanently 33 23 

Don’t know 46 40

 Totals 100 100

 Base n 168 53 

Table G-13. Where Respondent Moved From 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

San Diego area 88 79 

Other 12 21

 Totals 100 100

 Base n 170 53 

10
Table G-14. Like to Be as Independent as Possible 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Agree 84 88 

Neutral 13 8 

Disagree 4 4

 Totals 100 100

 Base n 170 51 

Table G-15. Like to Experiment with New Ways of Doing Things 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Agree 74 63 

Neutral 24 35 

Disagree 2 2

 Totals 100 100

 Base n 170 51 

Table G-16. Intrigued with New Technology 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Agree 81 80 

Neutral 16 18 

Disagree 3 2

 Totals 100 100

 Base n 169 51 

11
Table G-17. Seen as a Leader in Work, Social Life, or Volunteer Activities 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Agree 67 77 

Neutral 29 22 

Disagree 4 2

 Totals 100 100

 Base n 168 51 

Table G-18. Willing to Modify Lifestyle to Help Environment 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Agree 66 67 

Neutral 29 31 

Disagree 5 2

 Totals 100 100

 Base n 170 51 

Table G-19. Buy Environmentally Friendly Even If Costs More 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Agree 47 41 

Neutral 42 43 

Disagree 11 16

 Totals 100 100

 Base n 170 51 

12
Table G-20. Ceiling Fans 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Not owned 35 41 

Owned 65 59

 Totals 100 100

 Base n 171 51 

Table G-21. Dual-Zone Heating/Air-Conditioning System 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Not owned 36 37 

Owned 64 63

 Totals 100 100

 Base n 171 51 

Table G-22. Dimmer Switches for Lights 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Not owned 52 53 

Owned 49 47

 Totals 100 100

 Base n 171 51 

13
Table G-23. Compact Fluorescent Light Bulbs 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Not owned 56 47 

Owned 44 53

 Totals 100 100

 Base n 171 51 

Table G-24. Two Refrigerators 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Not owned 56 71 

Owned 44 29

 Totals 100 100

 Base n 171 51 

P2=3.67; p=055 

Table G-25. Hot Tub 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Not owned 81 69 

Owned 19 31

 Totals 100 100

 Base n 171 51 

P2=3.30; p=.068 

14
Table G-26. Pool 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Not owned 84 75 

Owned 16 26

 Totals 100 100

 Base n 171 51 

Table G-27. Standalone Freezer 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Not owned 87 82 

Owned 13 18

 Totals 100 100

 Base n 171 51 

Table G-28. Hot Water Flow Regulator 

Response Categories 

SheaHomes 

% 

Comparison Homes 

% 

Not owned 91 73 

Owned 9 28

 Totals 100 100

 Base n 171 51 

P2=12.069; p=.001 

15
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16
Appendix H

Detailed Factor Analysis Results

Cited in Chapter 17

H-1
Appendix H.

Detailed Factor Analysis Results

These factor analysis results were produced with SPSS 13.0. The principal components method 

was used to extract the initial components. The rotated component matrix was obtained using 

Varimax rotation with Kaiser normalization. A different number of iterations was required to 

converge to the solution shown in each table. 

2
Table H-1. Reasons for Purchase Rotated Component Matrix 

Component

Item 1 2 3 4 5 6

Purchase decision: close to work !.020 .057 .066 .735 .310 !.174 

Purchase decision: near to freeway .111 .144 !.004 .703 !.098 .268 

Purchase decision: near to services .206 .077 .316 .673 .099 .175 

Purchase decision: great view .097 !.121 .142 .141 .127 .581 

Purchase decision: safe and secure .093 .819 .045 .021 .093 .250 

Purchase decision: quality of schools .124 .627 .270 .260 !.105 !.182 

Purchase decision: knows area !.076 .305 .577 .015 .070 .381 

Purchase decision: close to friends .061 .004 .797 .019 .056 .106 

Purchase decision: close to parks/playgrounds .211 .100 .759 .202 .013 !.115 

Purchase decision: desirable area .113 .159 .443 .059 .613 .030 

Purchase decision: overall home value .228 .454 .054 .046 .474 !.141 

Purchase decision: investment potential .165 !.013 !.119 .119 .694 .375 

Purchase decision: no Mello-Roos taxes .301 .234 !.011 .077 !.024 .586 

Purchase decision: discount or incentive .461 !.027 !.021 .478 .104 .298 

Purchase decision: builder reputation .811 !.009 .033 .029 .168 .126 

Purchase decision: helpfulness of staff .821 .098 .133 !.011 .113 .032 

Purchase decision: quality of neighborhood/ .403 .609 .066 .042 .235 .015 

Purchase decision: exterior design .547 .126 .095 .121 .267 .113 

Purchase decision: feeling of community .576 .301 .076 .244 .010 !.034 

Purchase decision: availability of very .696 .220 .031 .119 !.136 .218 

3
Table H-2. Purchase Features Rotated Component Matrix 

Item

Component

1 2 3

Purchase feature: architectural design .690 .161 .131 

Purchase feature: size/square footage .346 .693 !.196 

Purchase feature: floor plan/layout .699 .328 !.082 

Purchase feature: number of bedrooms .202 .764 .027 

Purchase feature: three-car garage .057 .587 .341 

Purchase feature: granite counter tops as standard feature .295 .351 .579 

Purchase feature: large closets/pantries .547 .324 .440 

Purchase feature: single-story option .052 !.009 .739 

Purchase feature: lot size/yard .024 .576 .301 

Purchase feature: quality of construction .606 !.049 .282 

Purchase feature: spaciousness/openness .741 .177 .133 

Purchase feature: quality of sense light .766 .155 .166 

Purchase feature: many amenities included as standard features .507 .289 .457 

Purchase feature: availability of many options .542 .051 .424 

Purchase feature: quiet area .390 .084 .487 

4
Table H-3. Attitudes toward Solar Features Rotated Component Matrix 

Item

Component

1 2

Solar PV systems are a desirable innovation for new homes .922 .199 

Solar water heating systems are a desirable innovation for new homes .930 .203 

Solar PV systems are cost effective .145 .927 

Solar water heating systems are cost effective .260 .892 

Table H-4. Equipment Owned Rotated Component Matrix 

Item

Component

1 2 3 4

Own: two refrigerators !.032 .245 .679 .345 

Own: ceiling fans .108 .738 .161 !.118 

Own: standalone freezer .461 !.367 .403 .003 

Own: dimmer switches for lights .127 .778 !.091 .029 

Own: component flourescent light bulbs !.016 !.011 .237 !.690 

Own: hot tub .753 .125 !.022 !.084 

Own: hot water flow regulator .046 !.069 .749 !.222 

Own: pool .797 .153 .022 .067 

Own: dual zone heating/air conditioning system !.030 !.106 .199 .702 

5
Table H-5. Self-Reported Conservation Behaviors Rotated Component Matrix 

Item

Component

1 2 3

Behavior: in summer, set thermostat 75°F or higher .844 .115 .055 

Behavior: when away, modify thermostat settings .756 !.050 .077 

Behavior: turn off lights .240 .011 .774 

Behavior: turn off computers .022 .140 .756 

Behavior: more energy conscious than we used to be .032 .559 .315 

Behavior: use air conditioning less than in previous home .140 .751 .035 

Behavior: drive fuel-efficient vehicles !.023 .670 .132 

Behavior: in winter, set thermostat 70°F or lower .902 !.052 .057 

Behavior: conservative water !.048 .285 .808 

Behavior: practice xeriscaping !.135 .767 .062 

6
Table H-6. Energy Policy Preferences Rotated Component Matrix 

Component

Item 1 2 3

Policy: utility companies should give rebates for energy-efficient 

appliances .750 .311 .194 

Policy: federal income tax credits given to buyers of energyefficient homes .804 .271 .214 

Policy: homes technically rated efficient should be given ENERGY 

STAR label .258 .608 .157 

Policy: California Energy Commission should give rebates for PV .847 .293 .188 

Policy: California Energy Commission should give rebates for 

SWH .817 .207 .316 

Policy: federal government should support research on ZEH .185 .622 .476 

Policy: builders should build energy-efficient homes if cost is less .296 .869 .088 

Policy: builders should build energy-efficient homes if more 

comfortable and look better .218 .810 .154 

Policy: energy package should be standard if cost is effective .259 .704 .337 

Policy: affordable housing subsides for PV .308 .232 .897 

Policy: affordable housing subsides for SWH .300 .258 .896 

Table H-7. New Environmental Paradigm Rotated Component Matrix 

Item

Component

1 2

NEP: preserve environment for future generations !.158 .863 

NEP: threats to environment exaggerated .836 !.067 

NEP: federal regulations provide adequate protection for environment .844 !.056 

NEP: individuals need to take responsibility for environment !.035 .888 

NEP: household energy consumption not a major contributor to 

environmental problems .775 !.143 

7
Table H-8. Early Adopter Characteristics Rotated Component Matrix 

Item

Component

1 2

Like to be as independent as possible .722 !.060 

Like to experiment with new ways of doing things .607 .380 

Seen as leader in work, social, or volunteer .775 .072 

Buy environmentally friendly even if costs more .037 .867 

Willing to modify lifestyle to help environment .186 .835 

Intrigued with new technology .480 .265 

8
Table H-9. Satisfaction Rotated Component Matrix 

Item

Component

1 2 3 4

Satisfaction with home’s location !.105 .758 .032 !.014 

Satisfaction with investment potential of home .088 .726 .031 !.175 

Satisfaction with builder reputation .743 .207 .172 !.132 

Satisfaction with size/square footage .339 .724 .069 .074 

Satisfaction with layout/floor plan .483 .568 !.055 .299 

Satisfaction with storage space .398 .538 .069 .209 

Satisfaction with lot size and yard .351 .428 .105 !.106 

Satisfaction with quality of construction .831 .101 .178 !.074 

Satisfaction with number of thermostats .574 .064 !.030 .228 

Recode: perceived comfort of home overall .630 .355 .075 .029 

Recode: perceived energy efficiency of home overall .566 .021 .206 !.369 

Will buy energy efficiency in new home .082 .058 .827 !.094 

Will buy solar water heating in new home .159 .049 .879 !.005 

Will buy solar PV in new home .050 .054 .874 .046 

Would buy same home again .581 .084 !.003 !.013 

Recode 2: Estimated monthly utility bill !.032 !.032 !.001 .865 

9
Table H-10. Barriers to Solar PV Systems* Rotated Component Matrix 

Item

Component

1 2 3 4 5

PV barrier: energy is not that important .103 .175 .028 .003 .848 

PV barrier: it was too expensive .064 !.528 !.010 !.679 .058 

PV barrier: wanted other options instead !.650 .061 !.127 !.060 .523 

PV barrier: didn’t know enough to evaluate .151 !.088 .272 .589 .507 

PV barrier: didn’t know where it would go !.171 .076 .222 .860 !.021 

PV barrier: payback would be too long .211 !.822 .253 !.070 !.142 

PV barrier: thought homeowners insurance !.063 .110 .927 .203 !.091 

PV barrier: thought property taxes would !.029 !.008 .919 .131 .137 

PV barrier: unsure about the reliability of .783 !.214 -.011 .048 .193 

PV barrier: thought it would negatively .272 .784 .379 .023 .152 

PV barrier: could become outdated .841 .342 !.132 !.125 .020 

PV barrier: concerned about maintenance .788 .096 .046 !.096 .044 

PV barrier: did not like how the system .306 .598 .268 .362 !.004

 *Main homeowners who chose not to adopt PV only. 

10
Table H-11. Perceived Benefits of Solar PV Ownership Rotated Component Matrix 

Item

Component

1 2 3

Perceived benefits: reduces electricity bills .131 .792 .131 

Perceived benefits: sell excess electricity back to utility !.026 .692 .269 

Perceived benefits: provides free electricity once system is paid for .084 .750 .288 

Perceived benefits: increases home’s resale value .013 .560 .604 

Perceived benefits: protects against rising electricity costs .232 .534 .147 

Perceived benefits: increases self-sufficiency .229 .223 .832 

Perceived benefits: feels good to have it .526 .440 .556 

Perceived benefits: technologically innovative .327 .212 .713 

Perceived benefits: helps the environment .592 .546 .152 

Perceived benefits: increases our awareness of household energy use .473 .548 .321 

Perceived benefits: conserves natural resources .581 .539 !.195 

Perceived benefits: helps improve air quality in area .724 .281 .238 

Perceived benefits: benefits future generations .824 .290 .199 

Perceived benefits: helps reduce global warming .877 -.057 .150 

Perceived benefits: helps San Diego’s economy .849 -.047 .240 

11
Table H-12. Solar PV System Attributes Rotated Component Matrix 

Item

Component

1 2

PV attributes: importance of amount of electricity produced .811 .158 

PV attributes: finance through home mortgage .012 .740 

PV attributes: owning the solar PV system outright .354 .413 

PV attributes: net metering .365 .631 

PV attributes: digital display showing electricity production and consumption .800 .190 

PV attributes: length of warranty .797 .280 

PV attributes: ease of maintenance .757 .325 

PV attributes: attractiveness/unobtrusiveness of the system .258 .753 

PV attributes: upgrade capability .367 .709 

Table H-13. Information Channels Used Rotated Component Matrix 

Component

Item 1 2 3

Information channels: video on operation and maintenance .131 .122 .920 

Information channels: fact sheet about PV system !.616 !.497 .465 

Information channels: operating manual for PV system .868 !.209 .236 

Information channels: website !.122 .920 .132 

12
Table H-14. Uses of Digital Display Rotated Component Matrix 

Item

Component

1 2

Use digital display: obtain feedback on electricity use .744 .236 

Use digital display: determine whether anything left on in house .579 .303 

Use digital display: optimally schedule electricity-consuming chores .299 .780 

Use digital display: record cumulative electricity production and consumption !.051 .878 

Use digital display: become more sensitive to household electricity 

consumption .621 .117 

Use digital display: determine whether system is functioning .592 !.087 

Use digital display: help change energy-consuming behavior .788 .070 

Table H-15. Aspects Learned since Living with Solar PV Systems Rotated Component Matrix 

Items

Component

1 2

Learned about amount of electricity consumed the PV system produces .743 .157 

Learned about how the system works .782 .022 

Learned about net metering and interconnecting with grid .021 .776 

Learned about savings on utility bill .541 .116 

Learned about tax credits or rebates to help offset the cost .383 .554 

Learned about paycheck period for PV system purchase .365 .619 

Learned about other aspect of PV system !.001 .560 

13
Table H-16. Operational Aspects of Solar PV Systems Rotated Component Matrix 

Item

Component

1 2 3

PV operational aspects: system shuts down in power outage !.256 .501 .488 

PV operational aspects: paid retail rate for electricity put into grid .518 .129 .534 

PV operational aspects: have one electric meter .132 !.166 .790 

PV operational aspects: utility bills only for the electricity .603 .126 .151 

PV operational aspects: utility demand at peak on sunny afternoons .663 !.048 !.327 

PV operational aspects: have interconnectivity agreement with 

utility .685 !.136 .148 

PV operational aspects: pay electricity bill annually !.057 .783 .084 

PV operational aspects: receive check from utility annually for 

extra electricity !.174 !.684 .264 

14
Appendix H-1

Factors by Demographics 

H1-1
Appendix H1

Factors by Demographics

The tables in this appendix are for t-tests and analyses of variance of the study’s factors by 

demographics summarized in Chapter 19 (Analysis of Factors by Demographic Variables). 

The demographic variables included are gender, age, marital status, household composition, 

educational attainment, occupation, and annual household income. 

Differences in Factor Scores by Gender 

All 49 factors were analyzed by gender; three of the analyses resulted in significant differences. 

These three factors relate to home purchase decisions, attitudes toward solar features in new 

housing, and solar PV system attributes. Table H1-1 summarizes the findings from these 

analyses.

 Table H1-1. Factor Scores by Gender 

Factors 

Mean Z-Scores 

Male 

Mean Z-Scores 

Female 

Reasons for purchase: Safe and secure area 

(t= –2.316; p=.024) (Total n=195) 

–.160 

(n=110) 

.170 

(n=85) 

Attitudes toward solar features: Desirable innovation 

(t=2.053; p=.041) (Total n=210) 

.133 

(n=119) 

–.152 

(n=91) 

Solar PV system attributes: System performance (PV owners) 

(t=2.184; p=.033) (Total n=65) 

.179 

(n=45) 

–.384 

(n=20) 

Reasons for Purchase by Gender 

This dimension deals with concerns that homebuyers with families exhibit, including if the 

neighborhood is safe and secure and if the neighborhood and schools are high quality. As Table 

H1-1 shows, the t-test results in a significant difference between males and females on this 

dimension. The mean factor score is significantly lower for men than it is for women (p=.024). 

This suggests that the safety, security, and quality of the neighborhood is more significant and 

salient to women in the home purchase decision than they are to men. 

Attitudes toward Solar Features by Gender 

This dimension reflects the sense that solar PV and solar water heating systems are desirable 

innovations for new homes. As Table H1-1 shows, the t-test results in a significant difference 

between males and females on this dimension. The mean factor score is significantly higher for 

men than it is for women (p=.041). This suggests that men are generally more interested in and 

positive toward including these solar features in new housing than are women. 

2
Solar PV Systems Attributes by Gender 

This dimension reflects responses on the importance of PV system attributes, such as the amount 

of electricity produced, the digital display showing electricity production and consumption in real 

time, the length of the warranty, and the ease of maintenance. The mean factor score is 

significantly higher for men (p=.033) than it is for women. This suggests that female heads-ofhousehold are significantly less interested in PV system attributes than are their male partners. 

Differences in Factor Scores by Age 

The responses by age were recoded into three categories: (1) #39 years old, (2) 40–49 years old, 

and (3) $50 years old. All 49 factors were analyzed by these three age categories; nine of the 

analyses resulted in significant differences by age. These nine factors relate to home purchase 

decisions, home features, attitudes toward solar features in new housing, equipment owned, 

environmentalism and environmental attitudes, and PV information channels used. Table H1-2 

summarizes the findings from these analyses. 

Reasons for Purchase by Age 

Two of the dimensions of the home purchase decision factor analysis reported in Chapter 17 

were significantly different by age. The first dimension, called company reputation and 

performance, reflects respondent perception of and experience with the company that offered the 

home. The reputability of the builder, the helpfulness of the sales staff, and—to a lesser 

extent—the energy use aspects of the home combine to form this factor. As Table H1-2 shows, 

the mean factor score for the youngest age group is significantly lower than that of the middle 

and oldest age groups (p=.006), suggesting that this factor is less important in the home purchase 

decisions by the youngest homebuyers than by the older ones. The mean factor scores for those 

40–49 years of age and those aged 50 or older do not differ significantly from each other on this 

dimension. 

The second dimension under the home purchase decision category, called familiarity with the 

area, reflects previous knowledge of the area and the people who live there, as well as common 

areas for family and friends to gather. As Table H1-2 shows, the ANOVA results in a significant 

difference among age categories on this dimension. The mean factor score for the oldest age 

group is significantly lower than that of the youngest age group (p=.002), suggesting that this 

factor is more important in the home purchase decisions of the older homebuyers than of the 

younger ones. The mean factor scores for those 40–49 years of age is not significantly different 

from the other two age groups on this dimension. 

Home Features by Age 

One of the dimensions of the home purchase decision reported in Chapter 17 was significantly 

different—the availability of a single-story option, offered only by SheaHomes. As Table H1-2 

shows, there is a significant difference among age categories on this dimension. The mean factor 

score for the oldest age group is significantly higher than that of the other two age groups 

(p=.006), suggesting that this factor is more important in the home purchase decisions of the 

older homebuyers than of the younger ones. 

3
 Table H1-2. Factor Scores by Age 

Factors 

Mean ZScores 

#39 

Years Old 

Mean ZScores 

40 to 49 

Years Old 

Mean ZScores 

$50 

Years Old 

Reasons for purchase: Company reputation and 

performance 

(F=5.226; p=.006) (Total n=197) 

–.255 

(n=87) 

.236 

(n=61) 

.141 

(n=49) 

Reasons for purchase: Familiarity with area 

(F=6.543;p=.002) (Total n=197) 

.200 

(n=87) 

.016 

(n=61) 

–.431 

(n=49) 

Home feature: Single-story option 

(F=5.241; p=.006) (Total n=197) 

–.223 

(n=91) 

.142 

(n=59) 

.304 

(n=47) 

Attitudes toward solar features: Cost 

effectiveness of solar features 

(F=3.047; p=.05) (Total n=215) 

.022 

(n=95) 

.205 

(n=65) 

–.245 

(n=55) 

Equipment owned: Pool and hot tub combination 

(F=2.928; p=.056) (nears significance) 

(Total n=217) 

–.185 

(n=95) 

.192 

(n=64) 

.067 

(n=58) 

Equipment owned: Smaller efficiency measures 

(F=4.873; p=.009) (Total n=217) 

.199 

(n=95) 

–.0133 

(n=64) 

–.303 

(n=58) 

NEP: Environmental attitudes 

(F=6.579; p=.002) (Total n=217) 

–.274 

(n=96) 

.171 

(n=65) 

.245 

(n=56) 

Early adopter characteristics: Environmental 

attitudes 

(F=3.747; p=.025) (Total n=214) 

–.212 

(n=93) 

.102 

(n=65) 

.210 

(n=56) 

PV information channels used: Video (PV 

owners) 

(F=5.039; p=.01) (Total n=52) 

–.152 

(n=21) 

–.220 

(n=22) 

.892 

(n=9) 

Attitudes toward Solar Features by Age 

One of the dimensions of the attitudes toward solar features reported in Chapter 17 was 

significantly different—the sense that solar PV and solar water heating systems are cost effective 

in new housing. As Table H1-2 shows, the ANOVA results in a significant difference among age 

categories on this dimension. The mean factor score for the 40–49 year-old age group is 

significantly higher than that of the oldest age group (p=.05), suggesting that this factor is more 

important in the home purchase decisions of the homebuyers 40–49 years of age than of those 50 

or older. The mean factor scores for those 50 or older and those 39 or younger are not 

significantly different on this dimension. 

4
Equipment Owned by Age 

Two dimensions of the equipment owned reported in Chapter 17 were significantly different by 

age: (1) pool and hot tub combination, and (2) smaller efficiency measures. The first dimension 

reflects a tendency to own both a pool and hot tub. As Table H1-2 shows, the ANOVA results in 

a significant difference among age categories on this dimension. The difference in mean factor 

scores between the youngest age group and those who are 40–49 years of age nears significance 

(p=.056), suggesting that this factor may be less important in the home purchase decisions of the 

youngest homebuyers. The mean factor scores for those 40–49 years of age and those 50 years of 

age or older are not significantly different on this dimension. 

The second dimension under the equipment category, called smaller efficiency measures, 

includes smaller efficiency measures such as dimmer switches and ceiling fans. As Table H1-2 

shows, the ANOVA results in a significant difference among age categories on this dimension. 

The mean factor score for the oldest age group is significantly lower than that of the youngest age 

group (p=.009), suggesting that a greater tendency of the younger homebuyers than of oldest 

buyers to own these measures. The mean factor scores for those 40–49 years of age are not 

significantly different from the other two age groups on this dimension. 

Environmentalism and Environmental Attitudes by Age 

Two dimensions of the environmentalism and environmentalism factor analysis reported in 

Chapter 17 differ significantly by age: (1) anti-environmentalism, and (2) environmentalism. The 

first dimension reflects anti-environmentalist sentiments relative to environmental protection in 

general and to housing’s role in environmental problems. In general, a low score on this factor 

indicates a negative attitude toward the environment; conversely a high score indicates a positive 

attitude toward the environment. Table H1-2 shows that respondents in the youngest age group 

have a significantly lower mean factor score for environmental support (and may even be 

characterized as anti-environmental in their attitudes), whereas those 40–49 years of age have 

significantly higher mean scores. The 50+ age group’s mean environmentalism factor scores are 

the highest of the three age groups. Thus, the oldest buyers appear to be the most 

environmentally supportive. 

Environmental attitudes were also measured using two items presented with the early adopter 

characteristics described in Chapter 17. This dimension dealt with buying environmentally 

friendly products even if they cost more, and being willing to modify one’s lifestyle to help the 

environment. Table H1-2 shows that the mean factor score for the oldest age group is 

significantly lower than that of the other two age groups (p=.025), suggesting that the youngest 

homebuyers have significantly less tendency than do the middle and older age groups to take 

actions to preserve and improve the environment. The mean factor scores for those 40–49 years 

of age and those 50 years of age or older are not significantly different on this dimension. This 

result reinforces the findings from the environmentalism dimension reported above. 

5
PV Information Channels by Age 

One dimension of the PV information channels used reported in Chapter 17 primarily reflects use 

of a video on PV operations and maintenance as an important channel of PV information. As 

Table H1-2 shows, the ANOVA results in a significant difference among age categories on this 

dimension. The mean factor score for the oldest age group is significantly higher than that of the 

middle age group (p=.01), suggesting that the homebuyers 50 years of age or older are 

significantly more strongly inclined to use the video on PV operations and maintenance as a 

channel of PV information than are those of the other two age groups. The mean factor scores for 

those 40–49 years of age and those 39 years of age or younger are not significantly different from 

each other on this dimension. 

Differences in Factor Scores by Marital Status 

The responses on marital status were recoded in two categories: (1) married/in a committed 

relationship and (2) not married. All 49 factors were analyzed by marital status; seven of the 

analyses resulted in significant differences and the result of one additional analysis nears 

significance. These factors relate to home purchase decisions, home features, equipment owned, 

early adopter characteristics, barriers to PV purchase, and aspects learned since living with PV 

system. Table H1-3 summarizes the findings from these analyses. 

Reasons for Purchase by Marital Status 

Two dimensions of the home purchase decision factor analysis reported in Chapter 17 were 

significantly different by marital status. The first dimension, called convenience of access, 

involves convenience of access to and from the neighborhood in terms of closeness to work (for 

example, the I-15 freeway that runs north and south and can be taken to downtown San Diego) 

and the proximity of shopping centers and other services. As Table H1-3 shows, the mean factor 

score for the unmarried group is significantly lower than for the married group (p=.02), 

suggesting that these consideration are not important in the purchase decisions of unmarried 

heads-of-household. 

The second dimension reflects advantages of the property considered by homeowners at the time 

of purchase. The fact that these homes were exempt from Mello-Roos taxes—which could have 

amounted to as much as $500 to $700 a month—was a positive consideration. In addition, 

because the homes were built on a mesa some 15 miles east of the Pacific Ocean, they had 

pleasing views of the surrounding hills and, in some cases, of the ocean. As Table H1-3 shows, 

the mean factor score is significantly high for married than for unmarried respondents (p=.02), 

suggesting that they consider such advantages as no Mello-Roos taxes and great views as more 

important in their purchase decisions. 

Home Features by Marital Status 

Two dimensions of the home features factor analysis reported in Chapter 17 were significantly 

different by marital status. The first dimension under the home features category is called size of 

6
home and number of bedrooms. As Table H1-3 shows, the t-test results indicate that married 

homebuyers have a significantly higher mean factor score than unmarried buyers (p=.004) on this 

dimension. 

The second dimension concerned the availability of a single-story option, offered only by 

SheaHomes, which was critical to a subset of the homebuyers. As Table H1-3 shows, the mean 

factor score is significantly higher for the unmarried than for the married respondents (p=.038).

 Table H1-3. Factor Scores by Marital Status 

Factors 

Mean Z-Scores 

Married/In a 

Committed Relationship 

Mean Z-Scores 

Not Married 

Reasons for purchase: Convenience of access 

(t=2.354; p=.02) (Total n=196) 

.055 

(n=186) 

–.685 

(n=10) 

Reasons for purchase: Other advantages (no 

Mello-Roos taxes; great view) 

(t= –2.074; p=.039) (Total n=196) 

–.033 

(n=186) 

.638 

(n=10) 

Home features: Size of home and number of 

bedrooms 

(t=2.947; p=.004) (Total n=195) 

.060 

(n=183) 

–.809 

(n=12) 

Home features: Single-story option 

(t=2.087; p=.038) (Total n=195) 

–.028 

(n=183) 

.592 

(n=12) 

Equipment owned: Pool and hot tub combination 

(t=2.238; p=.038) (Total n=214) 

.017 

(n=201) 

–.358 

(n=13) 

Early adopter characteristics: Early adopter 

(opinion leader; independent, innovative) 

(t= –2.054; p=.041) (Total n=212) 

–.041 

(n=199) 

.544 

(n=13) 

Barriers to PV purchase: Tangible, immediate 

financial barriers (Main) 

(t= –2.049; p=.05) (Total n=30) 

–.099 

(n=27) 

.110 

(n=3) 

Aspects learned since living with PV system: 

technical aspects (PV owners) 

(t=2.40; p=.057; nears significance) (Total n=61) 

–.019 

(n=57) 

–.640 

(n=4) 

Equipment Owned by Marital Status 

This dimension reflects ownership of both hot tubs and pools together (as reported in Chapter 

17). The t-tests results in Table H1-3 suggest that married homebuyers are more strongly inclined 

to own pools and hot tubs in combination than are unmarried homebuyers (p=.038). 

7
Early Adopter Characteristics by Marital Status 

This dimension includes the variables that are intended to measure early adopter characteristics 

(opinion leadership, independence, and innovativeness), as reported in Chapter 17. The t-test 

results in Table H1-3 indicate a significantly higher mean factor score on early adopter 

characteristics among unmarried than among married respondents (p=.041). This suggests that 

unmarried homebuyers are more strongly inclined to respond that they have early adopter 

characteristics than are married homebuyers. 

Barriers to PV Purchase by Marital Status (Main Respondents Only) 

This dimension deals with tangible, immediate financial barriers reflecting concerns on the part 

of some main respondents that PV systems might result in unanticipated extra costs, such as 

increased homeowner insurance premiums and property taxes based on increased home 

valuation. These concerns suggest that the SheaHomes sales staff might not have explained the 

broader aspects of PV ownership to prospective homebuyers. The t-test results in Table H1-3 

indicate that unmarried respondents have a significantly higher mean factor score than do 

unmarried homeowners (p=.05), suggesting that unmarried respondents are more strongly 

inclined to be concerned about this dimension than unmarried respondents. 

Aspects Learned about Since Living with PV System: Technical Aspects by 

Marital Status (PV Owners Only) 

This dimension reflects responses that pertain to the technical aspects of the PV system, such as 

net metering, interconnectivity, and how the system works. The t-test results in Table H1-3 show 

that married heads-of-household have a higher mean factor score that nears significance (p=.057) 

than do unmarried ones on this dimension. This suggests that married PV owners seem to have 

learned about these technical aspects of PV systems somewhat more than unmarried respondents. 

Differences in Factor Scores by Household Composition 

The responses by household composition were recoded into two categories: (1) households with 

adults and children and (2) households with adults only. All 49 factors were analyzed by these 

two categories; nine of the analyses resulted in significant differences. These nine factors relate 

to reasons for purchase, home features, equipment owned, barriers to PV purchase, conservation 

behaviors, policy preferences, and use of digital display. Table H1-4 summarizes the findings 

from these analyses. 

Reasons for Purchase by Household Composition 

Four dimensions of the home purchase decision factor analysis reported in Chapter 17 are 

significantly different by household composition: safe and secure area, familiarity with the area, 

convenience of access, and other advantages such as no Mello-Roos taxes and great views. The 

first dimension reflects concerns that homebuyers with families exhibit, including if the 

8
neighborhood is safe and secure, if the schools are good, and, in general, if the home is in a highquality neighborhood. The mean factor score for households with children is significantly higher 

than adults-only households (p=.000). The t-test results in Table H1-4 indicate that households 

with children feel like this is more important than do households consisting of adults only.

 Table H1-4. Factor Scores by Household Composition 

Factors 

Mean Z-Scores 

Adults and Children 

Mean Z-Scores 

Adults Only 

Reasons for purchase: safe and secure area 

(t= –3.771; p=.000) (Total n=193) 

.200 

(n=132) 

–.424 

(n=61) 

Reasons for purchase: familiarity with area 

(t= –4.682; p=.000) (Total n=193) 

.225 

(n=132) 

–.466 

(n=61) 

Reasons for purchase: convenience of access 

(t= –2.933; p=.004) (Total n=193) 

.145 

(n=132) 

–.292 

(n=61) 

Reasons for purchase: other advantages (no MelloRoos taxes; great view) 

(t=2.395; p=.018) (Total n=193) 

–.103 

(n=132) 

.266 

(n=61) 

Home features: size of home and number of 

bedrooms 

(t= –2.586; p=.01) (Total n=191) 

.148 

(n=130) 

–.249 

(n=61) 

Policy preferences: financial incentives 

(t= –2.270; p=.024) (Total n=213) 

.095 

(n=146) 

–.238 

(n=67) 

Barriers to PV purchase: uncertainty about PV 

systems (Main) 

(t=2.279; p=.03) (Total n=30) 

–.265 

(n=20) 

.571 

(n=10) 

Conservation behaviors: adjusting thermostats 

(Main) 

(t=2.055; p=.041) (Total n=181) 

–.090 

(n=126) 

.242 

(n=55) 

Uses of digital display: optimizing electricity cost 

swings (PV owners) 

(t= !2.169; p=.034) (Total n=63) 

.108 

(n=46) 

!.331 

(n=17) 

The second dimension, familiarity with the area, reflects previous knowledge of the area and the 

people who live there, as well as common areas for family and friends to gather. The t-test results 

in Table H1-4 indicate that households with children have a significantly higher mean factor 

score on this dimension than households with adults only (p=.000). Although similar to the idea 

of a safe, secure, and high-quality neighborhood, familiarity with places and people forms a 

separate dimension. 

9
The third dimension involves convenience of access from the neighborhood in terms of closeness 

to work and the proximity of shopping centers and other services. The t-test results in Table H1-4 

indicate that the mean factor score on this dimension is significantly higher for homebuyers with 

children than for adults-only households (p=.004). 

The fourth dimension deals with other advantages of the property considered by homeowners at 

the time of purchase. The t-test results in Table H1-4 indicate that the mean factor score on this 

dimension is significantly higher for adults-only households than for homebuyers with children 

(p=.018). 

Home Features by Household Composition 

One dimension of home features factor analysis reported in Chapter 17 was the size of home and 

number of bedrooms. This dimension reflects the homebuyers’ interest in the number of 

bedrooms and the overall square footage of the home. The t-test results in Table H1-4 indicate 

that more homebuyers with children have a significantly higher factor score than do adults-only 

households (p=.01). 

Policy Preferences by Household Composition 

One dimension of the policy preferences factor analysis reported in Chapter 17 relates to 

preferences concerning financial incentives for energy efficiency and solar features, including 

rebates and tax credits from various levels of government and utility companies. Mean factor 

scores differ significantly by household composition; The t-test results in Table H1-4 indicate 

that households with children have significantly higher factor scores on this dimension than 

adults-only households (p=.024). 

Barriers to PV Purchase by Household Composition (Main Respondents Only) 

One dimension of the barriers to PV purchase factor analysis reported in Chapter 17 was 

uncertainty about PV systems. It reflects some main respondents’ concerns about the 

performance of solar PV systems—whether they would soon become outdated, whether they 

would require costly and difficult maintenance, and whether they would produce electricity 

reliably. The t-test results in Table H1-4 indicate that adults-only households have significantly 

higher mean factor score on this dimension than do households with children (p=.03). 

Conservation Behaviors by Household Composition (Main Respondents Only) 

One dimension of the self-reported conservation behavior factor analysis reported in Chapter 17 

had to do with adjusting thermostats in winter, summer, and when away. The t-test results in 

Table H1-4 indicate that households with children have significantly lower mean factor score on 

this dimension than adults-only households (p=.041), suggesting that adults-only households 

manage their thermostats more closely than families do. 

10
Uses of Digital Display by Household Composition (PV Owners Only) 

One dimension of the uses of digital display factor analysis reported in Chapter 17 relates to use 

of the display for feedback on system performance and electricity use. These responses pertain to 

using feedback about electricity use to manage energy-related behaviors and monitor electricity 

production and use. This suggests that, when possible, a household might try to use appliances on 

sunny afternoons when their electricity production is highest and might avoid other uses at that 

time or when their electricity production is lower. Mean factor scores differ significantly by 

household composition on this dimension. The t-test results in Table H1-4 indicate that 

households with children have a significantly higher mean factor score than do adults-only 

households on this dimension (p=.034), suggesting that families in PV households tend to use the 

digital displays to manage their electricity-related household chores, whereas households with 

children do not. 

Differences in Factor Scores by Educational Attainment 

The questionnaire responses on educational attainment were recoded into five categories: (1) 

high school graduate or below, (2) some college, (3) bachelor’s degree or bachelor’s degree plus, 

(4) master’s degree or master’s plus, and (5) doctoral degree. All 49 factors were analyzed by 

these five categories of educational attainment; seven of these analyses resulted in significant 

differences by this variable. These seven factors relate to reasons for home purchase, importance 

of home features, attitude toward solar features in new housing, conservation behaviors, and 

early adopter characteristics. Table H1-5 summarizes the findings from these analyses. 

Reasons for Purchase by Educational Attainment 

Three of the dimensions of the home purchase decision factor analysis reported in Chapter 17 are 

significantly different by age. The first dimension, builder reputation and performance, reflects 

respondent perception of and experience with the company that offered the home. The 

reputability of the builder, the helpfulness of the sales staff, and—to a lesser extent—the energy 

use aspects of the home combine to form this factor. The t-test results in Table H1-5 indicate that 

homebuyers with some college have a significantly higher mean factor score than do those with 

Bachelor’s, Master’s, or doctoral degrees (p=.034). 

The second dimension, familiarity with area, reflects previous knowledge of the area and the 

people who live there, as well as common areas for family and friends to gather. The F-test 

results in Table H1-5 indicate that homebuyers with some college have a significantly lower 

mean score on this dimension than do high school graduates or those with baccalaureate or more 

advanced degrees (p=.008). 

The third dimension, other advantages of the home (e.g., no Mello-Roos taxes and great views), 

reflects other advantages of the property considered by homeowners at the time of purchase. The 

F-test results in Table H1-5 indicate that only those with a master’s or master’s plus or a 

doctorate do not seem to be concerned with this dimension (p=.031). 

11
 Table H1-5. Factor Scores by Educational Attainment 

Factors 

Mean 

Z-Scores 

H.S. Grad 

or Below 

Mean 

Z-Scores 

Some 

College 

Mean 

Z-Scores 

Bachelor’s or 

Bachelor’s 

Plus 

Mean 

Z-Scores 

Master’s or 

Master’s 

Plus 

Mean 

Z-Scores 

Doctorate 

Reasons for purchase: 

Builder reputation and 

performance 

(F=2.662; p=.034) 

(Total n=195) 

–.068 

(n=10) 

.501 

(n=28) 

–.047 

(n=82) 

–.085 

(n=45) 

–.292 

(n=30) 

Reasons for purchase: 

Familiarity with area 

(f=3.523; p=.008) 

(Total n=195) 

.198 

(n=10) 

–.576 

(n=28) 

.215 

(n=82) 

–.058 

(n=45) 

–.072 

(n=30) 

Reasons for purchase: 

Other advantages (no 

Mello-Roos taxes; great 

view) 

(F=2.720; p=.031) 

(Total n=195) 

.614 

(n=10) 

.111 

(n=28) 

.097 

(n=82) 

–.163 

(n=45) 

–.386 

(n=30) 

Home features: Singlestory option 

(F=4.205; p=.003) 

(Total n=194) 

.424 

(n=12) 

.420 

(n=30) 

.062 

(n=82) 

–.244 

(n=40) 

–.427 

(n=30) 

Attitudes toward solar 

features: Desirable 

innovation 

(F=3.980; p=.004) 

(Total n=212) 

.214 

(n=12) 

–.650 

(n=30) 

.107 

(n=86) 

.043 

(n=50) 

.150 

(n=34) 

Conservation behavior: 

Adjusting thermostats 

(F=2.673; p=.034) 

(Total n=183) 

–.339 

(n=11) 

–.238 

(n=27) 

.240 

(n=79) 

–.274 

(n=39) 

.055 

(n=27) 

Early adopter 

characteristics: Early 

adopter (opinion leader, 

independent, innovative) 

(F=2.883; p=.024) 

(Total n=213) 

.808 

(n=12) 

–.236 

(n=32) 

.035

 (n=86) 

–.159 

(n=50) 

.069 

(n=33) 

12
Home Features by Educational Attainment 

One dimension of the home features factor analysis reported in Chapter 17 is the single-story 

option. This option was offered only by SheaHomes. The F-test results in Table H1-5 indicate 

that responding heads of households with doctorates have significantly lower mean scores on the 

dimension than do all others, save those with Master’s degrees. Responding heads of households 

with high school or some college have the highest mean scores on this dimension (p=.003). 

Attitudes toward Solar Features by Educational Attainment 

One dimension of the attitudes toward solar features factor analysis reported in Chapter 17 is the 

desirability of solar PV and solar water heating systems as innovations in new housing. The Ftest results in Table H1-5 indicate that respondents who had some college education have a 

significantly lower mean factor score on this dimension than do all other respondents (p=.004). 

Conservation Behavior by Educational Attainment 

One dimension of the conservation behaviors factor analysis reported in Chapter 17 involves 

adjusting thermostats in winter, summer, and when away. The F-test results in Table H1-5 

indicate that respondents with a bachelor’s or bachelors plus have a significantly higher factor 

score on this factor than do other groups (p=.034). 

Early Adopter Characteristics by Educational Attainment 

One dimension of the early-adopter factor analysis discussed in Chapter 17 involves such early 

adopter characteristics as opinion leadership, independence, and innovativeness. The F-test 

results in Table H1-5 indicate that high school graduates have significantly higher mean factor 

score on this factor than do all other groups (p=.024). This indicates that high-school graduates 

(or below) are more strongly inclined to see themselves as opinion leaders, independent, and 

innovative than any other education grouping. This result does not square with the prediction by 

diffusion theory that innovators and early adopters tend to be more highly educated. 

Differences in Factor Scores by Occupation 

These responses on occupation were recoded into two categories: (1) science and engineering 

occupations and (2) all other occupations. All 49 factors were analyzed by these two occupational 

categories, resulting in four significant differences by occupation. These four factors relate to 

satisfaction with home purchase, appliances and equipment owned, solar PV system attributes, 

and aspects learned about since living with solar PV systems. Table H1-6 summarizes the 

findings from these analyses. 

13
 Table H1-6. Factor Scores by Occupation 

Factors 

Mean Z-Scores 

Science and Engineering 

Occupations 

Mean Z-Scores 

All Other 

Occupations 

Satisfaction: Estimated monthly utility bill 

(t= –2.904; p=.004) (Total n=155) 

–.332 

(n=53) 

.157 

(n=102) 

Equipment owned: Measures for comfort (dualzone heating/air-conditioning system; CFLs) 

(t= –3.274; p=.001) (Total n=189) 

–.359 

(n=60) 

.148 

(n=129) 

Solar PV system attributes: System performance 

(PV owners) 

(t=2.225; p=.028) (Total n=60) 

.321 

(n=25) 

–.251 

(n=35) 

Learned since living with solar PV systems: 

Technical aspects (PV owners) 

(t=3.915; p=.000) (Total n=57) 

.492 

(n=25) 

–.432 

(n=32) 

Satisfaction by Occupation 

One dimensions of the satisfaction factor analysis reported in Chapter 17 is the estimated 

monthly utility bill. The questionnaires asked all respondents to estimate their monthly utility 

bills. These responses were recoded from the actual dollar amounts reported by classifying the 

dollar amounts into five categories; each category contained 20% of the responses. The 

categories are (1) #$80 per month, (2) $80.01–$110, (3) $110.01–$150, (4) $150.01–$210, and 

(5) >$210.The t-test results in Table H1-6 indicate that respondents in the science and 

engineering occupations have a significantly lower mean factor score on the estimated monthly 

utility bill factor (p=.004). 

Equipment Owned by Occupation 

One dimension of the equipment-owned factor analysis reported in Chapter 17 concerns 

measures for comfort, including ownership of dual-zone heating and air-conditioning systems 

and CFLs. This dimension shows a significant difference by occupation. The F-test results in 

Table H1-6 indicate that those in science and engineering have a significantly lower factor score 

on the measures-for-comfort dimension than those in all other occupations (p=.001). 

Solar PV System Attributes by Occupation 

One dimension of the solar PV system attributes factor analysis reported in Chapter 17 is system 

performance, which differs significantly by occupation. This factor reflects responses on the 

importance of PV system performance and reliability, as well as feedback on the amount of 

electricity produced so that PV owners will know the system is performing well. The F-test 

results in Table H1-6 indicate that the mean factor score for scientists and engineers is 

significantly higher than the score for those in all other occupations (p=.028). 

14
Aspects Learned Since Living with Solar PV Systems by Occupation 

(PV Owners Only) 

A dimension of the factor analysis on aspects learned since living with solar PV systems reported 

in Chapter 17 is technical aspects. Technical aspects was the only dimension in this factor to 

differ significantly by occupation. This dimension reflects responses that seem to pertain to the 

technical aspects of the PV system, such as net metering, interconnectivity, and how the system 

works. The F-test results in Table H1-6 indicate that scientists and engineers have a significantly 

higher mean factor score on this dimension than do respondents in all other occupations 

(p=.000). 

Differences in Factor Scores by Annual Household Income 

These responses by income were recoded into three categories: (1) #$99,000, (2) $100,000 to 

$199,000, and (3) $$200,000. All 49 factors were analyzed by these three income categories; 

four of the analyses resulted in significant differences by income. These four factors relate to 

reasons for purchase, home features, equipment owned, and PV information channels employed. 

Table H1-7 summarizes the findings from these analyses.

 Table H1-7. Factor Scores by Annual Household Income 

Factors 

Mean 

Z-Scores 

#$99,999 

Mean 

Z-Scores 

$100,000 to 

$199,000 

Mean 

Z-Scores 

$$200,000 

Reasons for purchase: Safe and secure area 

(F=3.319; p=.038) (Total n=180) 

–.041 

(n=39) 

.136 

(n=113) 

–.412 

(n=28) 

Home features: Overall design (quality of light; 

spaciousness) 

(F=3.611; p=.029) (Total n=178) 

–.326 

(n=39) 

.160 

(n=112) 

–.111 

(n=27) 

Equipment owned: Smaller efficiency measures 

(dimmer switches; ceiling fans) 

(F=3.350; p=.037) (Total n=198) 

–.308 

(n=42) 

.023 

(n=126) 

.277 

(n=30) 

PV information channels: Web sites (PV owners) 

(F=6.605; p=.003) (Total n=49) 

–.076 

(n=12) 

–.322 

(n=26) 

.857 

(n=11) 

Reasons for Purchase by Annual Household Income 

One dimension of the reasons for the purchase factor analysis reported in Chapter 17 is the safety 

and security of the area. As discussed earlier, it reflects concerns that the area is safe, the schools 

good, and the home high-quality. The F-test results in Table H1-7 indicate that homebuyers with 

an annual household income of $$200,000 have a significantly lower mean score on this 

dimension than do those with incomes (p=.038). 

15
Home Features by Annual Household Income 

One dimension of the home features factor analysis reported in Chapter 17 is the home’s overall 

design (quality of light; spaciousness). As noted earlier, this reflects aspects of the house’s 

overall design, including quality of light, sense of openness, spaciousness, layout, and 

architectural design. The F-test results in Table H1-7 indicate that respondents with an annual 

household income of #$99,000 have a significantly lower mean factor score on this dimension 

than do those with incomes between $100,000 and $199,999 (p=.029). 

Equipment Owned by Annual Household Income 

One dimension of the equipment-owned factor analysis reported in Chapter 17 relates to smaller 

efficiency measures (dimmer switches; ceiling fans), showed significant differences by annual 

income. The F-test results in Table H1-7 indicate that respondents with an annual household 

income of #$99,000 have a significantly lower factor score than those with incomes $$200,000 

(p=.037). 

PV Information Channels by Annual Household Income (PV Owners Only) 

One dimension of this factor, Web sites, shows significant differences by income. PV owners 

were asked which channels they had used to gather information about their PV systems. The 

questionnaire mentioned four such channels: a video on operations and maintenance, a fact sheet 

about solar PV systems, an operating manual, and Web sites (see Chapter 9, Knowledge and 

Information). The F-test results in Table H1-7 (p=.003) indicate that respondents with an annual 

household income of #$99,000 and those with incomes of $100,000 to $199,000 are less 

inclined to use Web sites as PV information channels than are those with an annual income of 

$$200,000. 

Summary of Demographic Differences on Study Factors by Categories of 

Homebuyers 

Among all respondents, the differences highlight the desire of women, families with children, 

and those with annual incomes of $100,000–$199,999 to live in a safe, secure area. Familiarity 

with the area is important to younger buyers, families with children at home, and buyers #39 

years of age. It is also more important to high-school graduates and those with a bachelor’s 

degree. Convenience of access is a more important factor for the married than the unmarried 

homebuyers, and for households with both adults and children. 

In considering reasons for purchase, builder reputation and performance are more important to 

those 40–49 years of age and to those with some college. Other advantages of the new homes 

(e.g., no Mello Roos taxes and great views) are more important to the unmarried, adults-only 

households, and high-school graduates. 

16
In considering home features, the size of the home and number of bedrooms are more important 

to households with children. Overall design is more important to those with annual incomes of 

$100,000–$199,999. Weighing in the purchase decision of some respondents is the single-story 

option, which is more important to those 50+ years of age, the unmarried, and those with high 

school or some college. 

The only difference on satisfaction factors found after respondents had lived in their homes for at 

least six months was by occupation: scientists and engineers are significantly more satisfied with 

their monthly utility bills than are others. 

Males are more strongly inclined to believe solar features are a desirable innovation in new; least 

inclined to believe this are those with some college. Those 40–49 years of age believe solar 

features are cost effective. 

Equipment owned also differentiates among respondents on a few key demographic variables. 

The pool and hot tub combination is more frequently owned by those 40–49 years of age than 

other age groups, and by the married. Smaller efficiency measures are more frequently owned by 

those #39 years of age and by those with incomes $$200,000. Measures for comfort (such as 

dual-zone heating and air-conditioning systems) are more frequently owned by those working in 

non-scientific occupations. 

Regarding resource-conservation behaviors, adjusting thermostats reportedly occurs more 

frequently among adults-only households and those with Master’s degrees. 

Perhaps surprisingly, environmentalism is found to be strongest among the oldest respondents 

(50 years of age or older) and weakest among the those 39 years of age or younger. Perhaps the 

younger buyers expect the environmental aspects to be taken care of routinely, whereas the older 

buyers feel more of a sense of personal responsibility for environmental protection and less trust 

in institutions to foster environmental protection. 

The unmarried homebuyers more frequently exhibit early adopter characteristics than do the 

married ones to exhibit early-adopter characteristics. As would not be expected, those with the 

lowest educational attainment exhibit higher early-adopter characteristics. 

To promote solar features in new housing, homebuyers with children are more strongly inclined 

to prefer financial incentives such as tax credits and rebates than do adults-only households. 

Among main respondents, the unmarried are more concerned about the tangible, immediate 

financial barriers to PV purchase, and households with children are more uncertain about the PV 

purchase than are the buyers living in adults-only households. 

Among PV owners, solar PV system performance is more significant to males than to females. 

Technical aspects learned since living with the PV system are somewhat more important to the 

17
married householders and to scientists and engineers. The digital display showing electricity 

consumption and production in real time is less important to the adults-only households than to 

the families with children. Relative to information channels for obtaining information of PV 

systems, the 50+ age group is more strongly inclined to use the video on PV system operations 

and maintenance and the highest-income group is more strongly inclined to use Web sites. 

18
Appendix J 

Scatter Diagrams of Average Monthly Electricity Consumption

by Average Monthly Electricity Cost for All Homes in the Study 

Cited in Chapter 20 

J-1
Figure J-1. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost ($), Excluding Taxes and Miscellaneous Charges,

for All Homes Combined (n=109)

2
Figure J-2. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost ($), Excluding Taxes and Miscellaneous Charges,

for Homes in the SheaHomes Communities with PV Systems (n=37)

3
Figure J-3. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost ($), Excluding Taxes and Miscellaneous Charges,

for Homes in the SheaHomes Communities without PV Systems (n=44)

4
Figure J-4. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost ($), Excluding Taxes and Miscellaneous Charges,

for Homes in the Comparison Community (n=28)

5
Figure J-5. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost ($), Including Taxes and Miscellaneous Charges,

for All Homes Combined (n=109)

6
Figure J-6. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost ($), Including Taxes and Miscellaneous Charges,

for Homes in the SheaHomes Communities with PV Systems (n=37)

7
Figure J-7. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost ($), Including Taxes and Miscellaneous Charges,

for Homes in the SheaHomes Communities without PV Systems (n=44)

8
Figure J-8. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost ($), Including Taxes and Miscellaneous Charges,

for Homes in the Comparison Community (n=28)

9
Figure J-9. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and 

Average Monthly Electricity Cost ($)/ft2

, Excluding Taxes and

Miscellaneous Charges, for All Homes Combined (n=109)

10
Figure J-10. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and 

Average Monthly Electricity Cost ($)/ft2

, Excluding Taxes and Miscellaneous Charges, for Homes in

the SheaHomes Communities with PV Systems (n=37)

11
Figure J-11. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and 

Average Monthly Electricity Cost ($)/ft2

, Excluding Taxes and Miscellaneous Charges, for Homes

in the SheaHomes Communities without PV Systems (n=44)

12
Figure J-12. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and 

Average Monthly Electricity Cost ($)/ft2

, Excluding Taxes and Miscellaneous Charges, for Homes

in the SheaHomes Communities without PV Systems (n=44)

13
Figure J-13. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and 

Average Monthly Electricity Cost ($)/ft2

, Including Taxes and Miscellaneous Charges, for 

All Homes Combined (n=109)

14
Figure J-14. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and 

Average Monthly Electricity Cost ($)/ft2

, Including Taxes and Miscellaneous Charges, for Homes in

the SheaHomes Communities with PV Systems (n=37)

15
Figure J-15. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and Average

Monthly Electricity Cost ($)/ft2

, Including Taxes and Miscellaneous Charges, for 

Homes in the SheaHomes Communities without PV Systems (n=44)

16
Figure J-16. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and 

Average Monthly Electricity Cost ($)/ft2

, Including Taxes and Miscellaneous Charges, for Homes in

the Comparison Community (n=28)

17
Appendix K 

Scatter Diagrams of Average Monthly Gas Consumption 

by Average Cost for All Homes in the Study 

Cited in Chapter 20 

K-1
Figure K-1. Comparison of Average Monthly Gas Consumption (therms) and 

Average Monthly Gas Cost ($), Excluding Taxes and Miscellaneous Charges, 

for All Homes Combined (n=109) 

2
Figure K-2. Comparison of Average Monthly Gas Consumption (therms) and 

Average Monthly Gas Cost ($), Excluding Taxes and Miscellaneous Charges, 

for Homes in the SheaHomes Community with PV Systems (n=37) 

3
Figure K-3. Comparison of Average Monthly Gas Consumption (therms) and 

Average Monthly Gas Cost ($), Excluding Taxes and Miscellaneous Charges,

 for Homes in the SheaHomes Community without PV Systems (n=44) 

4
Figure K-4. Comparison of Average Monthly Gas Consumption (therms) and 

Average Monthly Gas Cost ($), Excluding Taxes and Miscellaneous Charges, 

for Homes in the Comparison Community (n=28) 

5
Figure K-5. Comparison of Average Monthly Gas Consumption (therms) and 

Average Monthly Gas Cost ($), Including Taxes and Miscellaneous Charges, 

for All Homes Combined (n=109) 

6
Figure K-6. Comparison of Average Monthly Gas Consumption (therms) and 

Average Monthly Gas Cost ($), Including Taxes and Miscellaneous Charges, 

for Homes in the SheaHomes Community with PV Systems (n=37) 

7
Figure K-7. Comparison of Average Monthly Gas Consumption (therms) and 

Average Monthly Gas Cost ($), Including Taxes and Miscellaneous Charges, 

for Homes in the SheaHomes Community without PV Systems (n=44) 

8
Figure K-8. Comparison of Average Monthly Gas Consumption (therms) and 

Average Monthly Gas Cost ($), Including Taxes and Miscellaneous Charges, 

for Homes in the Comparison Community (n=28) 

9
Figure K-9. Comparison of Average Monthly Gas Consumption (therms)/ft2

 and 

Average Monthly Gas Cost ($)/ft2

, Excluding Taxes and Miscellaneous Charges, 

for All Homes Combined (n=109) 

10
Figure K-10. Comparison of Average Monthly Gas Consumption (therms)/ft2

 and 

Average Monthly Gas Cost ($)/ft2

, Excluding Taxes and Miscellaneous Charges, 

for All Homes Combined (n=109) 

11
Figure K-11. Comparison of Average Monthly Gas Consumption (therms)/ft2

 and 

Average Monthly Gas Cost ($)/ft2

, Excluding Taxes and Miscellaneous Charges, 

for Homes in the SheaHomes Communities without PV Systems (n=44) 

12
Figure K-12. Comparison of Average Monthly Gas Consumption (therms)/ft2

 and 

Average Monthly Gas Cost ($)/ft2

, Excluding Taxes and Miscellaneous Charges, 

for Homes in the Comparison Community (n=28) 

13
Figure K-13. Comparison of Average Monthly Gas Consumption (therms)/ft2

 and 

Average Monthly Gas Cost ($)/ft2

, Including Taxes and Miscellaneous Charges, 

for All Homes Combined (n=109) 

14
Figure K-14. Comparison of Average Monthly Gas Consumption (therms)/ft2

 and 

Average Monthly Gas Cost ($)/ft2

, Including Taxes and Miscellaneous Charges, 

for Homes in the SheaHomes Communities with PV Systems (n=37) 

15
Figure K-15. Comparison of Average Monthly Gas Consumption (therms)/ft2

 and 

Average Monthly Gas Cost ($)/ft2

, Including Taxes and Miscellaneous Charges, 

for Homes in the SheaHomes Communities without PV Systems (n=44) 

16
Figure K-16. Comparison of Average Monthly Gas Consumption (therms)/ft2

 and 

Average Monthly Gas Cost ($)/ft2

, Including Taxes and Miscellaneous Charges, 

for Homes in the Comparison Community (n=28) 

17
Appendix L

Line Graphs for Month-to-Month Consumption of

Electricity for Individual Homes in the Study

Cited in Chapter 20 

L-1
(a) 

0 

500 

1 000 

1 500 

2 000 

2 500 

3 000 

Jun-03 Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 Feb-04 

Mar-04 

Apr-04 

May-04 Jun-04 

Jul-04 

Electricity Consumption (kWh) 

R3 R1 1 R1 3 

(b) 

0 

50 

100 

150 

200 

250 

300 

350 

Jun-03 

Jul-03 

Aug-03 Sep-03 

Oct-03 

Nov-03 Dec-03 

Jan-04 Feb-04 

Mar-04 

Apr-04 

May-04 

Jun-04 

Jul-04 

Gas Consumption (Therms) 

R3 R1 1 R1 3 

Figure L1. Monthly Utility Consumption in Early Homes: (a) Electricity and (b) Gas. 

2
(a) 

0 

500 

1000 

1500 

2000 

2500 

3000 

Jun-03 Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 Feb-04 

Mar-04 

Apr-04 May-04 Jun-04 Jul-04 

Electricity Consumption (kWh) 

R14 R17 R37 R40 R41 R44 R52 R53 R67 R76 

(b) 

0 

50 

100 

150 

200 

250 

300 

350 

Jun-03 

Jul-03 

Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 

Feb-04 

Mar-04 

Apr-04 

May-04 

Jun-04 

Jul-04 

Gas Consumption (Therms) 

R14 R17 R37 R40 R41 R44 R52 R53 R67 R76 

Figure L2. Monthly Utility Consumption in the First 10 PV Homes: (a) Electricity and (b) Gas. RID53 

is a Statistical Outlier with Regard to Total 12-Month Electricity Consumption. 

3
(a) 

0 

500 

1000 

1500 

2000 

2500 

3000 

Jun-03 Jul-03 

Aug-03 

Sep-03 

Oct-03 

Nov-03 Dec-03 

Jan-04 

Feb-04 Mar-04 

Apr-04 

May-04 Jun-04 

Jul-04 

Electricity Consumption (kWh) 

R77 R79 R82 R86 R98 R112 R113 R116 R140 R142 

(b) 

0 

50 

100 

150 

200 

250 

300 

350 

Jun-03 Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 

Feb-04 Mar-04 

Apr-04 

May-04 Jun-04 Jul-04 

Gas Consumption (Therms) 

R77 R79 R82 R86 R98 R112 R113 R116 R140 R142 

Figure L3. Monthly Utility Consumption in the Second 10 PV Homes: (a) Electricity and (b) Gas.

RID113 and RID142 are Statistical Outliers with Regard to Total 12-Month Gas Consumption.

4
(a) 

0 

500 

1000 

1500 

2000 

2500 

3000 

Jun-03 Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 Dec-03 

Jan-04 Feb-04 Mar-04 

Apr-04 May-04 

Jun-04 

Jul-04 

Electricity Consumption (kWh) 

R146 R149 R157 R180 R183 R187 R188 R189 R204 R205 

(b) 

0 

50 

100 

150 

200 

250 

300 

350 

Jun-03 

Jul-03 

Aug-03 Sep-03 Oct-03 Nov-03

Dec-03 

Jan-04 

Feb-04 

Mar-04 

Apr-04 May-04 Jun-04 

Jul-04 

Gas Consumption (Therms) 

R146 R149 R157 R180 R183 R187 R188 R189 R204 R205 

Figure L4. Monthly Utility Consumption in the Third 10 PV Homes: (a) Electricity and (b) Gas. 

5
(a) 

0 

500 

1000 

1500 

2000 

2500 

3000 

Jun-03 Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 Dec-03 

Jan-04 Feb-04 Mar-04 

Apr-04 May-04 Jun-04 Jul-04 

Electricity Consumption (kWh) 

R221 R226 R243 R249 R263 R264 R265 R269 R274 R276 

(b) 

0 

50 

100 

150 

200 

250 

300 

350 

Jun-03 

Jul-03 

Aug-03 Sep-03

Oct-03 Nov-03Dec-03

Jan-04 

Feb-04Mar-04 

Apr-04 May-04 

Jun-04 

Jul-04 

Gas Consumption (Therms) 

R221 R226 R243 R249 R263 R264 R265 R269 R274 R276 

Figure L5. Monthly Utility Consumption in the Fourth 10 PV Homes: (a) Electricity and (b) Gas. 

6
(a) 

0 

500 

1000 

1500 

2000 

2500 

3000 

Jun-03 Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 Feb-04 

Mar-04 Apr-04 May-04 Jun-04 Jul-04 

Electricity Consumption (kWh) 

R15 R16 R19 R20 R23 R24 R26 R35 R46 R50 

(b) 

0 

50 

100 

150 

200 

250 

300 

350 

Jun-03 

Jul-03 

Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 

Feb-04 

Mar-04 

Apr-04 

May-04 

Jun-04 

Gas Consumption (Therms) 

R15 R16 R19 R20 R23 R24 R26 R35 R46 R50 

Figure L6. Monthly Utility Consumption in the First 10 SEE Homes: (a) Electricity and (b) Gas.

RID16 and RID46 are Statistical Outliers with Regard to Both Total 12-Month Electricity

Consumption and Total 12-Month Gas-Consumption.

7
(a) 

0 

500 

1000 

1500 

2000 

2500 

3000 

Jun-03 

Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 Dec-03 

Jan-04 Feb-04 Mar-04 Apr-04 

May-04 Jun-04 

Jul-04 

Electricity Consumption (kWh) 

R54 R58 R71 R75 R94 R104 R114 R115 R117 R118 

(b) 

0 

50 

100 

150 

200 

250 

300 

350 

Jun-03 Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 Dec-03 

Jan-04 

Feb-04 Mar-04 

Apr-04 

May-04 Jun-04 

Jul-04 

Gas Consumption (Therms) 

R54 R58 R71 R75 R94 R104 R114 R115 R117 R118 

Figure L7. Monthly Utility Consumption in the Second 10 SEE Homes: (a) Electricity and (b) Gas. 

RID118 is a Statistical Outlier with Regard to Total 12-Month Electricity Consumption and RID94 is 

a Statistical Outlier with Regard to Total 12-Month Gas Consumption. 

8
(a)

0 

500 

1000 

1500 

2000 

2500 

3000 

Jun-03 Jul-03 

Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 

Feb-04 

Mar-04 Apr-04 May-04 

Jun-04 

Jul-04 

Electricity Consumption (kWh) 

R123 R131 R133 R148 R153 R161 R170 R175 R182 R184 

(b) 

0 

50 

100 

150 

200 

250 

300 

350 

Jun-03 

Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 

Feb-04 

Mar-04 Apr-04 

May-04 Jun-04 

Jul-04 

Gas Consumption (Therms) 

R123 R131 R133 R148 R153 R161 R170 R175 R182 R184 

Figure L8. Monthly Utility Consumption in the Third 10 SEE Homes: (a) Electricity and (b) Gas. 

9
(a) 

0 

500 

1000 

1500 

2000 

2500 

3000 

Jun-03 

Jul-03 

Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 

Feb-04 

Mar-04 

Apr-04 

May-04 

Jun-04 

Jul-04 

Electricity Consumption (kWh) 

R190 R194 R196 R201 R208 R223 R225 R233 R238 R241 

(b) 

0 

50 

100 

150 

200 

250 

300 

350 

Jun-03 Jul-03 

Aug-03 

Sep-03 

Oct-03 

Nov-03 Dec-03 

Jan-04 Feb-04 Mar-04 Apr-04 May-04 

Jun-04 Jul-04 

Gas Consumption (Therms) 

R190 R194 R196 R201 R208 R223 R225 R233 R238 R241 

Figure L9. Monthly Utility Consumption in the Fourth 10 SEE Homes: (a) Electricity and (b) Gas. 

10
(a) 

0 

500 

1000 

1500 

2000 

2500 

3000 

Jun-03 Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 Dec-03 

Jan-04 

Feb-04Mar-04 

Apr-04 

May-04 Jun-04 Jul-04 

Electricity Consumption (kWh) 

R242 R245 R254 R255 R257 R258 R270 R277 

(b) 

0 

50 

100 

150 

200 

250 

300 

350 

Jun-03 Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 Dec-03 

Jan-04 

Feb-04 Mar-04 

Apr-04 

May-04 Jun-04 

Jul-04 

Gas Consumption (Therms) 

R242 R245 R254 R255 R257 R258 R270 R277 

Figure L10. Monthly Utility Consumption in the Last Eight SEE Homes: (a) Electricity and (b) Gas. 

11
(a) 

0 

500 

1000 

1500 

2000 

2500 

3000 

Jun-03 Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 Feb-04 

Mar-04 

Apr-04 

May-04 

Jun-04 Jul-04 

Electricity Consumption (kWh) 

R310 R311 R317 R322 R324 R325 R330 R336 R344 R345 

(b) 

0 

50 

100 

150 

200 

250 

300 

350 

Jun-03 

Jul-03 

Aug-03 

Sep-03 

Oct-03 

Nov-03 Dec-03 

Jan-04 

Feb-04 Mar-04 

Apr-04 May-04 Jun-04 

Jul-04 

Gas Consumption (Therms) 

R310 R311 R317 R322 R324 R325 R330 R336 R344 R345 

Figure L11. Monthly Utility Consumption in the First 10 Comparison Homes: (a) Electricity and 

(b) Gas. RID322 is a Statistical Outlier with Regard to Total 12-Month Gas Consumption. 

12
(a) 

0 

500 

1000 

1500 

2000 

2500 

3000 

Jun-03 

Jul-03 

Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 

Feb-04 Mar-04 Apr-04 

May-04 

Jun-04 Jul-04 

Electricity Consumption (kWh) 

R348 R350 R352 R357 R358 R363 R365 R368 R371 R372 

(b) 

0 

50 

100 

150 

200 

250 

300 

350 

Jun-03 

Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 

Feb-04 

Mar-04 

Apr-04 May-04 Jun-04 

Jul-04 

Gas Consumption (Therms) 

R348 R350 R352 R357 R358 R363 R365 R368 R371 R372 

Figure L12. Monthly Utility Consumption in the Second 10 Comparison Homes: (a) Electricity and 

(b) Gas. RID368 is a Statistical Outlier with Regard to Total 12-Month Electricity Consumption. 

13
(a) 

0 

500 

1000 

1500 

2000 

2500 

3000 

Jun-03 

Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 Feb-04 Mar-04 Apr-04 May-04 Jun-04 

Jul-04 

Electricity Consumption (kWh) 

R374 R381 R382 R386 R387 R388 R389 R394 R397 R403 R407 

(b) 

0 

50 

100 

150 

200 

250 

300 

350 

Jun-03 Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 Dec-03 

Jan-04 Feb-04 Mar-04 

Apr-04 

May-04 

Jun-04 

Jul-04 

Gas Consumption (Therms) 

R374 R381 R382 R386 R387 R388 R389 R394 R397 R403 R407 

Figure L13. Monthly Utility Consumption in the Last 11 Comparison Homes: (a) Electricity and 

(b) Gas. RID374 is a Statistical Outlier with Regard to Total 12-Month Gas Consumption. 

14
(a) 

0 

500 

1000 

1500 

2000 

2500 

3000 

Jun-03 Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 Feb-04 Mar-04 Apr-04 May-04 Jun-04 

Jul-04 

Electricity Consumption (kWh) 

R44 R86 R98 R112 R149 R274 

(b) 

0 

50 

100 

150 

200 

250 

300 

350 

Jun-03 

Jul-03 Aug-03 

Sep-03 

Oct-03 

Nov-03 

Dec-03 

Jan-04 Feb-04 Mar-04 Apr-04 

May-04 

Jun-04 Jul-04 

Gas Consumption (Therms) 

R44 R86 R98 R112 R149 R274 

Figure L14. Monthly Utility Consumption in PV Homes with 2.4-kW Systems: 

(a) Electricity and (b) Gas. 

15
Appendix M 

Line Graphs for Month-to-Month Consumption of 

Gas for Individual Homes in the Study 

Cited in Chapter 20 

M-1
(a)

0

500

1000

1500

2000

2500

3000

Jun-03

Jul-03Aug-03

Sep-03

Oct-03

Nov-03Dec-03

Jan-04Feb-04

Mar-04

Apr-04

May-04Jun-04Jul-04

Electricity Consumption (kWh) 

R3 R11 R13

(b)

0

50

100

150

200

250

300

350

Jun-03

Jul-03

Aug-03Sep-03Oct-03Nov-03

Dec-03Jan-04Feb-04

Mar-04

Apr-04

May-04Jun-04

Jul-04

Gas Consumption (Therms) 

R3 R11 R13

Figure M1. Monthly Utility Consumption in Early Homes: (a) Electricity and (b) Gas. Homes with

Pools are Indicated in Red, Homes with Hot Tubs are Indicated in Blue, Homes with Both are

Indicated in Magenta, and Homes with Neither are Indicated in Black.

2
(a)

0

500

1000

1500

2000

2500

3000

Jun-03Jul-03Aug-03

Sep -03

Oct-03

Nov-03

Dec-03

Jan-04

Feb-04Mar-04

Apr-04

May-04

Jun-04

Jul-04

Electricity Consumption (kWh) 

R14 R17 R37 R40 R41 R44 R52 R53 R67 R76

(b)

0

50

100

150

200

250

300

350

Jun-03

Jul-03

Aug-03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04

Feb-04

Mar-04

Apr-04

May-04

Jun-04

Jul-04

Gas Consumption (Therms) 

R14 R17 R37 R40 R41 R44 R52 R53 R67 R76

Figure M2. Monthly Utility Consumption in the First 10 PV Homes: (a) Electricity and (b) Gas.

RID44 has a 2.4-kW System, Whereas all Others have 1.2-kW Systems. Homes with Pools are

Indicated in Red, Homes with Hot Tubs are Indicated in Blue, Homes with Both are Indicated in

Magenta, and Homes with Neither are Indicated in Black. RID53 is a Statistical Outlier with

Regards to Total 12-Month Electricity Consumption.

3
(a)

0

500

1000

1500

2000

2500

3000

Jun-03Jul-03Aug-03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04

Feb-04Mar-04Apr-04May-04

Jun-04

Jul-04

Electricity Consumption (kWh) 

R77 R79 R82 R86 R98 R112 R113 R116 R140 R142

(b)

0

50

100

150

200

250

300

350

Jun-03

Jul-03

Aug -03

Sep -03

Oct-03

Nov-03Dec-03

Jan-04

Feb-04Mar-04Apr-04

May-04Jun-04

Jul-04

Gas Consumption (Therms) 

R77 R79 R82 R86 R98 R112 R113 R116 R140 R142

Figure M3. Monthly Utility Consumption in the Second 10 PV Homes: (a) Electricity and (b) Gas. 

RID86, RID98, and RID112 have 2.4-kW Systems, Whereas all Others have 1.2-kW Systems. Homes 

with Pools are Indicated in Red, Homes with Hot Tubs are Indicated in Blue, Homes with Both are 

Indicated in Magenta, and Homes with Neither are Indicated in Black. RID113 and RID142 are 

Statistical Outliers with Regard to Total 12-Month Gas Consumption. 

4
(a)

0

500

1000

1500

2000

2500

3000

Jun-03Jul-03Aug-03

Sep-03

Oct-03

Nov-03Dec-03

Jan-04

Feb-04

Mar-04Apr-04May-04

Jun-04Jul-04

Electricity Consumption (kWh) 

R146 R149 R157 R180 R183 R187 R188 R189 R204 R205

(b)

0

50

100

150

200

250

300

350

Jun-03

Jul-03

Aug-03

Sep-03Oct-03

Nov-03

Dec-03

Jan-04

Feb-04

Mar-04Apr-04May-04

Jun-04

Jul-04

Gas Consumption (Therms) 

R146 R149 R157 R180 R183 R187 R188 R189 R204 R205

Figure M4. Monthly Utility Consumption in the Third 10 PV Homes: (a) Electricity and (b) Gas.

RID149 has a 2.4-kW System, Whereas all Others have 1.2-kW Systems. Homes with Pools are

Indicated in Red, Homes with Hot Tubs are Indicated in Blue, Homes with Both are Indicated in

Magenta, and Homes with Neither are Indicated in Black.

5
(a)

0

500

1000

1500

2000

2500

3000

Jun-03Jul-03Aug -03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04Feb-04Mar-04

Apr-04May-04

Jun-04Jul-04

Electricity Consumption (kWh) 

R221 R226 R243 R249 R263 R264 R265 R269 R274 R276

(b)

0

50

100

150

200

250

300

350

Jun-03

Jul-03

Aug-03Sep-03Oct-03Nov-03Dec-03Jan-04

Feb-04

Mar-04

Apr-04

May-04Jun-04

Jul-04

Gas Consumption (Therms) 

R221 R226 R243 R249 R263 R264 R265 R269 R274 R276

Figure M5. Monthly Utility Consumption in the Fourth 10 PV Homes: (a) Electricity and (b) Gas.

RID274 has a 2.4-kW System, Whereas all Others have 1.2-kW Systems. Homes with Pools are

Indicated in Red, Homes with Hot Tubs are Indicated in Blue, Homes with Both are Indicated in

Magenta, and Homes with Neither are Indicated in Black.

6
(a)

0

500

1000

1500

2000

2500

3000

Jun-03Jul-03

Aug-03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04Feb-04Mar-04Apr-04

May-04Jun-04

Jul-04

Electricity Consumption (kWh) 

R15 R16 R19 R20 R23 R24 R26 R35 R46 R50

(b)

0

50

100

150

200

250

300

350

Jun-03

Jul-03

Aug-03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04

Feb-04

Mar-04

Apr-04

May-04

Jun-04

Gas Consumption (Therms) 

R15 R16 R19 R20 R23 R24 R26 R35 R46 R50

Figure M6. Monthly Utility Consumption in the First 10 SEE Homes: (a) Electricity and (b) Gas. 

Homes with Pools are Indicated in Red, Homes with Hot Tubs are Indicated in Blue, Homes with 

Both are Indicated in Magenta, and Homes with Neither are Indicated in Black. RID16 and RID46 

are Statistical Outliers with Regard to Both 12-Month Total Electricity Consumption and 12-Month 

Total Gas Consumption. 

7
(a)

0

500

1000

1500

2000

2500

3000

Jun-03Jul-03

Aug-03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04Feb-04Mar-04Apr-04

May-04Jun-04

Jul-04

Electricity Consumption (kWh) 

R54 R58 R71 R75 R94 R104 R114 R115 R117 R118

(b)

0

50

100

150

200

250

300

350

Jun-03

Jul-03Aug -03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04

Feb-04

Mar-04

Apr-04May-04

Jun-04Jul-04

Gas Consumption (Therms) 

R54 R58 R71 R75 R94 R104 R114 R115 R117 R118

Figure M7. Monthly Utility Consumption in the Second 10 SEE Homes: (a) Electricity and (b) Gas.

Homes with Pools are Indicated in Red, Homes with Hot Tubs are Indicated in Blue, Homes with

Both are Indicated in Magenta, and Homes with Neither are Indicated in Black. RID118 is a

Statistical Outlier with Regard to 12-Month Total Electricity Consumption and RID94 is a Statistical

Outlier with Regard to 12-Month Total Gas Consumption.

8
(a)

0

500

1000

1500

2000

2500

3000

Jun-03

Jul-03Aug-03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04

Feb-04

Mar-04

Apr-04

May-04Jun-04

Jul-04

Electricity Consumption (kWh) 

R123 R131 R133 R148 R153 R161 R170 R175 R182 R184

(b)

0

50

100

150

200

250

300

350

Jun-03Jul-03Aug -03

Sep -03

Oct-03

Nov-03

Dec-03

Jan-04

Feb-04

Mar-04

Apr-04

May-04

Jun-04

Jul-04

Gas Consumption (Therms) 

R123 R131 R133 R148 R153 R161 R170 R175 R182 R184

Figure M8. Monthly Utility Consumption in the Third 10 SEE Homes: (a) Electricity and (b) Gas.

Homes with Pools are Indicated in Red, Homes with Hot Tubs are Indicated in Blue, Homes with

Both are Indicated in Magenta, and Homes with Neither are Indicated in Black.

9
(a)

0

500

1000

1500

2000

2500

3000

Jun-03

Jul-03

Aug-03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04

Feb-04

Mar-04

Apr-04

May-04

Jun-04

Jul-04

Electricity Consumption (kWh) 

R190 R194 R196 R201 R208 R223 R225 R233 R238 R241

(b)

0

50

100

150

200

250

300

350

Jun-03Jul-03Aug -03

Sep -03

Oct-03

Nov-03Dec-03

Jan-04Feb-04

Mar-04

Apr-04

May-04

Jun-04

Jul-04

Gas Consumption (Therms) 

R190 R194 R196 R201 R208 R223 R225 R233 R238 R241

Figure M9. Monthly Utility Consumption in the Fourth 10 SEE Homes: (a) Electricity and (b) Gas.

Homes with Pools are Indicated in Red, Homes with Hot Tubs are Indicated in Blue, Homes with

Both are Indicated in Magenta, and Homes with Neither are Indicated in Black.

10
(a)

0

500

1000

1500

2000

2500

3000

Jun-03Jul-03

Aug -03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04

Feb-04Mar-04Apr-04

May-04

Jun-04

Jul-04

Electricity Consumption (kWh) 

R242 R245 R254 R255 R257 R258 R270 R277

(b)

0

50

100

150

200

250

300

350

Jun-03Jul-03Aug-03

Sep-03

Oct-03

Nov-03Dec-03

Jan-04Feb-04

Mar-04Apr-04May-04Jun-04

Jul-04

Gas Consumption (Therms) 

R242 R245 R254 R255 R257 R258 R270 R277

Figure M10. Monthly Utility Consumption in the Last Eight SEE Homes: (a) Electricity and (b) Gas.

Homes with Pools are Indicated in Red, Homes with Hot Tubs are Indicated in Blue, Homes with

Both are Indicated in Magenta, and Homes with Neither are Indicated in Black.

11
(a)

0

500

1000

1500

2000

2500

3000

Jun-03Jul-03Aug-03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04Feb-04Mar-04

Apr-04

May-04Jun-04

Jul-04

Electricity Consumption (kWh) 

R310 R311 R317 R322 R324 R325 R330 R336 R344 R345

(b)

0

50

100

150

200

250

300

350

Jun-03

Jul-03

Aug -03

Sep-03

Oct-03

Nov-03Dec-03

Jan-04

Feb-04Mar-04

Apr-04

May-04Jun-04Jul-04

Gas Consumption (Therms) 

R310 R311 R317 R322 R324 R325 R330 R336 R344 R345

Figure M11. Monthly Utility Consumption in the First 10 Comparison Homes: (a) Electricity and (b) 

Gas. Homes with Pools are Indicated in Red, Homes with Hot Tubs are Indicated in Blue, Homes 

with Both are Indicated in Magenta, and Homes with Neither are Indicated in Black. RID322 is a 

Statistical Outlier with Regard to Total 12-Month Gas Consumption. 

12
(a)

0

500

1000

1500

2000

2500

3000

Jun-03Jul-03

Aug-03

Sep-03

Oct-03

Nov-03Dec-03

Jan-04

Feb-04Mar-04

Apr-04

May-04Jun-04Jul-04

Electricity Consumption (kWh) 

R348 R350 R352 R357 R358 R363 R365 R368 R371 R372

(b)

0

50

100

150

200

250

300

350

Jun-03Jul-03Aug -03

Sep -03

Oct-03

Nov-03Dec-03

Jan-04Feb-04Mar-04Apr-04

May-04Jun-04Jul-04

Gas Consumption (Therms) 

R348 R350 R352 R357 R358 R363 R365 R368 R371 R372

Figure M12. Monthly Utility Consumption in the Second 10 Comparison Homes: (a) Electricity and 

(b) Gas. Homes with Pools are Indicated in Red, Homes with Hot Tubs are Indicated in Blue, 

Homes with Both are Indicated in Magenta, and Homes with Neither are Indicated in Black. RID368 

is a Statistical Outlier with Regard to Total 12-Month Electricity Consumption. 

13
(a)

0

500

1000

1500

2000

2500

3000

Jun-03Jul-03

Aug-03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04Feb-04

Mar-04Apr-04May-04Jun-04Jul-04

Electricity Consumption (kWh) 

R374 R381 R382 R386 R387 R388 R389 R394 R397 R403 R407

(b)

0

50

100

150

200

250

300

350

Jun-03

Jul-03

Aug-03

Sep-03

Oct-03

Nov-03Dec-03

Jan-04

Feb-04Mar-04Apr-04

May-04Jun-04

Jul-04

Gas Consumption (Therms) 

R374 R381 R382 R386 R387 R388 R389 R394 R397 R403 R407

Figure M13. Monthly Utility Consumption in the Last 11 Comparison Homes: (a) Electricity and (b) 

Gas. Homes with Pools are Indicated in Red, Homes with Hot Tubs are Indicated in Blue, Homes 

with Both are Indicated in Magenta, and Homes with Neither are Indicated in Black. RID374 is a 

Statistical Outlier with Regard to Total 12-Month Gas Consumption. 

14
(a)

0

500

1000

1500

2000

2500

3000

Jun-03Jul-03

Aug-03

Sep -03

Oct-03

Nov-03

Dec-03

Jan-04

Feb-04Mar-04Apr-04May-04Jun-04Jul-04

Electricity Consumption (kWh) 

R53 R98 R113 R142 R263 R310 R322 R324 R336

R357 R389 R403 R16 R182 R372

(b)

0

50

100

150

200

250

300

350

Jun-03Jul-03Aug-03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04Feb-04

Mar-04Apr-04

May-04

Jun-04

Jul-04

Gas Consumption (Therms) 

R53 R98 R113 R142 R263 R310 R322 R324 R336

R357 R372 R389 R403 R16 R182

Figure M14. Monthly Utility Consumption in Homes with Pools: (a) Electricity and (b) Gas. PV

Homes are Indicated in Blue, SEE Homes are Indicated in Red, and Comparison Homes are

Indicated in Black. RID98 is a PV Home with a 2.4-kW System. RID16 and RID53 are Statistical

Outliers with Regard to Total 12-Month Electricity Consumption. RID16, RID113, RID142, and

RID322 are Statistical Outliers with Regard to Total 12-Month Gas Consumption.

15
(a)

0

500

1000

1500

2000

2500

3000

Jun-03

Jul-03

Aug-03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04

Feb-04

Mar-04

Apr-04

May-04

Jun-04

Jul-04

Electricity Consumption (kWh) 

R41 R67 R204 R226 R358 R374 R397 R46 R54

R94 R117 R118 R223 R371

(b)

0

50

100

150

200

250

300

350

Jun-03Jul-03Aug-03

Sep -03

Oct-03

Nov-03Dec-03

Jan-04

Feb-04

Mar-04Apr-04

May-04

Jun-04

Jul-04

Gas Consumption (Therms) 

R41 R67 R204 R226 R358 R371 R374 R397 R46

R54 R94 R117 R118 R223

Figure M15. Monthly Utility Consumption in Homes with Both Pools and Hot Tubs: (a) Electricity 

and (b) Gas. PV Homes are Indicated in Blue, SEE Homes are Indicated in Red, and Comparison 

Homes are Indicated in Black. RID46 and RID118 are Statistical Outliers with Regard to Total 12-

Month Electricity Consumption. RID46, RID94, and RID374 are Statistical Outliers with Regard to 

Total 12-Month Gas Consumption. 

16
(a)

0

500

1000

1500

2000

2500

3000

Jun-03Jul-03

Aug -03

Sep -03

Oct-03

Nov-03

Dec-03

Jan-04

Feb-04Mar-04Apr-04May-04Jun-04

Jul-04

Electricity Consumption (kWh) 

R77 R149 R187 R221 R243 R274 R317 R344 R345 R348

R386 R387 R388 R71 R123 R161 R194 R238 R241 R352

(b)

0

50

100

150

200

250

300

350

Jun-03Jul-03

Aug -03

Sep -03

Oct-03

Nov-03Dec-03

Jan-04Feb-04

Mar-04Apr-04May-04

Jun-04

Jul-04

Gas Consumption (Therms) 

R77 R149 R221 R243 R274 R317 R344 R345 R348 R352

R386 R387 R388 R71 R123 R161 R194 R238 R241 R187

Figure M16. Monthly Utility Consumption in Homes with Neither Pools nor Hot Tubs: (a) Electricity 

and (b) Gas. PV Homes are Indicated in Blue, SEE Homes are Indicated in Red, and Comparison 

Homes are Indicated in Black. RID149 and RID274 are PV Homes with 2.4-kW Systems. RID368 is a 

Statistical Outlier with Regard to Total 12-Month Electricity Consumption. 

17
(a)

0

500

1000

1500

2000

2500

3000

Jun-03Jul-03

Aug-03

Sep-03

Oct-03

Nov-03

Dec-03

Jan-04

Feb-04

Mar-04Apr-04May-04

Jun-04

Jul-04

Electricity Consumption (kWh) 

R44 R86 R98 R112 R149 R274

(b)

0

50

100

150

200

250

300

350

Jun-03

Jul-03Aug -03

Sep -03

Oct-03

Nov-03

Dec-03

Jan-04

Feb-04Mar-04

Apr-04

May-04

Jun-04

Jul-04

Gas Consumption (Therms) 

R44 R86 R98 R112 R149 R274

Figure M17. Monthly Utility Consumption in PV Homes with 2.4-kW Systems: (a) Electricity and (b) 

Gas. Homes with Pools are Indicated in Red, Homes with Hot Tubs are Indicated in Blue, Homes 

with Both are Indicated in Magenta, and Homes with Neither are Indicated in Black. 

18
Appendix N

Descriptive Statistics

12-Month Utility Consumption and Cost Data

N-1
Table N-1. Descriptive Statistics on Electricity and

Natural Gas Consumption, July 2003SJune 2004 (n=109*)

Statistic 

Total 12-Month 

Electricity 

Consumption 

(kWh) 

Average Monthly 

Electricity 

Consumption 

(kWh)

 Total 12-

Month Gas 

Consumption 

(therms)

 Average 

Monthly Gas 

Consumption 

(therms) 

Minimum 267.0 22.3 100.0 8.3 

Mean 7,959.4 664.2 419.0 35.1 

Median 7,698.0 641.8 417.0 34.8 

Maximum 17,707.0 1,475.9 893.0 74.7 

Standard deviation 3,658.2 305.3 160.0 13.4 

Coefficient of 

variation 46.0% 46.0% 38.2% 38.2% 

*Outlier and early homes excluded 

Table N-2. Descriptive Statistics on Electricity and 

Natural Gas Consumption per Square Foot, July 2003SJune 2004 (n=109*) 

Statistic 

Average Monthly Electricity 

Consumption/ft2 (kWh)

 Average Monthly Gas 

Consumption/ft2 (therms) 

Minimum .009 .000 

Mean .221 .012 

Median .208 .013 

Maximum .527 .030 

Standard deviation .103 .005 

Coefficient of variation 46.6% 41.7% 

*Outlier and early homes excluded 

2
Table N-3. Comparative Descriptive Statistics on Electricity and Natural Gas Consumption,

July 2003SJune 2004, for Homes in the SheaHomes and Comparison Communities

Development Statistic 

Total 

12-Month 

Electricity 

Consumption 

(kWh) 

Average 

Monthly 

Electricity 

Consumption 

(kWh)

 Total 

12-Month 

Gas 

Consumption 

(therms) 

Average 

Monthly 

Gas 

Consumption 

(therms) 

SheaHomes 

(n=81*) 

Minimum 267.0 22.3 100.0 8.3 

Mean 7,425.8 619.9 391.9 32.8 

Median 6,967.0 581.4 384.0 32.3 

Maximum 16,741.0 1,399.8 739.0 61.9 

Standard 

deviation 3,341.1 279.0 139.2 11.6 

Coefficient 

of variation 45.0% 45.0% 35.5% 35.5% 

Comparison 

community 

(n=28*) 

Minimum 3,716.0 309.4 202.0 16.9 

Mean 9,502.8 792.6 497.3 41.6 

Median 9,050.0 754.9 526.5 44.0 

Maximum 17,707.0 1,475.9 893.0 74.7 

Standard 

deviation 4,138.6 345.3 190.7 15.9 

Coefficient 

of variation 43.6% 43.6% 38.3% 38.3% 

*Outlier and early homes excluded 

3
Table N-4. Comparative Descriptive Statistics on Electricity and Natural Gas Consumption per

Square Foot, July 2003SJune 2004, for Homes in the SheaHomes and Comparison Communities

Development Statistic 

Average Monthly Electricity 

Consumption/ft2 (kWh) 

Average Monthly Gas 

Consumption/ft2 (therms) 

SheaHomes 

(n=81*) 

Minimum .009 .000 

Mean .200 .011 

Median .191 .011 

Maximum .489 .020 

Standard 

deviation .088 .004 

Coefficient 

of variation 44.0% 36.4% 

Comparison 

community 

(n=28*) 

Minimum .124 .010 

Mean .282 .015 

Median .272 .015 

Maximum .527 .030 

Standard 

deviation .119 .006 

Coefficient 

of variation 42.2% 40.0% 

*Outlier and early homes excluded 

4
Table N-5. Comparative Descriptive Statistics on Electricity and Natural Gas Consumption,

July 2003SJune 2004, for Homes in the SheaHomes Communities

with and without Solar PV Systems

Home 

Category Statistic 

Total 

12-Month 

Electricity 

Consumption 

(kWh) 

Average 

Monthly 

Electricity 

Consumption 

(kWh)

 Total 

12-Month 

Gas 

Consumption 

(therms) 

Average 

Monthly 

Gas 

Consumption 

(therms) 

Minimum 267.0 22.3 100.0 8.3 

Mean 6,368.9 531.7 366.0 30.7 

With PV 

(n=37*) 

Median 6,535.0 545.5 333.0 27.9 

Maximum 12,868.0 1,073.4 678.0 56.6 

Standard 

deviation 3,206.6 267.5 140.0 11.7 

Coefficient 

of variation 50.3% 50.3% 38.2% 38.2% 

Minimum 3,333.0 277.7 128.0 10.7 

Mean 8,314.7 694.0 413.7 34.6 

Without PV 

(n=44*) 

Median 8,098.0 676.1 424.0 35.4 

Maximum 16,741.0 1,399.8 739.0 61.9 

Standard 

deviation 3,223.5 269.4 136.4 11.4 

Coefficient 

of variation 38.8% 38.8% 33.0% 33.0% 

*Outlier and early homes excluded 

5
Table N-6. Comparative Descriptive Statistics on Electricity and Natural Gas Consumption per

Square Foot, July 2003SJune 2004, for Homes in the SheaHomes Communities

with and without Solar PV Systems

Home 

Category Statistic 

Average Monthly Electricity 

Consumption/ft2

 (kWh) 

Average Monthly Gas 

Consumption/ft2 (therms) 

Minimum .009 .000 

Mean .174 .010 

With PV 

(n=37*) 

Median .173 .009 

Maximum .415 .020 

Standard 

deviation .088 .004 

Coefficient 

of variation 50.6% 40.0% 

Minimum .090 .000 

Mean .222 .011 

Without PV Median .217 .012 

(n=44*) Maximum .489 .020 

Standard 

deviation .083 .004 

Coefficient 

of variation 37.4% 36.4% 

*Outlier and early homes excluded 

6
Table N-7. Comparative Descriptive Statistics on Electricity and Natural Gas Consumption,

July 2003SJune 2004, for Homes in the Comparison Community and Homes in the 

SheaHomes Communities without Solar PV Systems

Home 

Category Statistic 

Total 

12-Month 

Electricity 

Consumption 

(kWh) 

Average 

Monthly 

Electricity 

Consumption 

(kWh)

 Total 

12-Month 

Gas 

Consumption 

(therms) 

Average 

Monthly 

Gas 

Consumption 

(therms) 

Minimum 3,716.0 309.4 202.0 16.9 

Mean 9,502.8 792.6 497.3 41.6 

Comparison 

community 

(n=28*) 

Median 9,050.0 754.9 526.5 44.0 

Maximum 17,707.0 1,475.9 893.0 74.7 

Standard 

deviation 4,138.6 345.3 190.7 15.9 

Coefficient 

of variation 43.6% 43.6% 38.3% 38.3% 

Minimum 3,333.0 277.7 128.0 10.7 

Mean 8,314.7 694.0 413.7 34.6 

SheaHomes, Median 8,098.0 676.1 424.0 35.4 

without PV 

(n=44*) 

Maximum 1,6741.0 1,399.8 739.0 61.9 

Standard 

deviation 3,223.5 269.4 136.4 11.4 

Coefficient 

of variation 38.8% 38.8% 33.0% 33.0% 

*Outlier and early homes excluded 

7
Table N-8. Comparative Descriptive Statistics on Electricity and Natural Gas Consumption per

Square Foot, July 2003SJune 2004, for Homes in the Comparison Community and Homes in the

SheaHomes Communities without Solar PV Systems

Home 

Category Statistic 

Average Monthly Electricity 

Consumption/ft2

 (kWh) 

Average Monthly Gas 

Consumption/ft2 (therms) 

Minimum .124 .010 

Comparison 

community 

(n=28*) 

Mean .282 .015 

Median .272 .015 

Maximum .527 .030 

Standard 

deviation .119 .006 

Coefficient 

of variation 42.2% 40.0% 

Minimum .090 .000 

Mean .222 .011 

SheaHomes, 

without PV 

(n=44*) 

Median .217 .012 

Maximum .489 .020 

Standard 

deviation .083 .004 

Coefficient 

of variation 37.4% 36.4% 

*Outlier and early homes excluded 

8
 

Table N-9. Descriptive Statistics on Electricity Costs, July 2003SJune 2004 (n=109*) 

Statistic 

Total 12-Month 

Electricity Cost, 

no Taxes or 

Miscellaneous 

Charges 

Average Monthly 

Electricity Cost, 

no Taxes or 

Miscellaneous 

Charges 

Total 12-Month 

Electricity Cost, 

including Taxes and 

Miscellaneous 

Charges 

Average Monthly 

Electricity Cost, 

including Taxes and 

Miscellaneous 

Charges 

Minimum $ 35.76 $ 2.99 $ 76.35 $ 6.39 

Mean $1,180.75 $ 98.54 $1,295.31 $108.10 

Median $1,113.00 $ 92.71 $1,220.08 $101.71 

Maximum $2,775.20 $231.88 $3,037.61 $253.80 

Standard 

deviation $ 607.45 $ 50.70 $ 662.84 $ 55.32 

Coefficient 

of 

variation

 51.4% 51.4% 51.2% 51.2% 

*Outlier and early homes excluded 

Table N-10. Descriptive Statistics on Gas Costs, July 2003SJune 2004 (n=109*) 

Statistic 

Total 12-Month 

Gas Cost, 

no Taxes or 

Miscellaneous 

Charges 

Average Monthly 

Gas Cost, 

no Taxes or 

Miscellaneous 

Charges 

Total 12-Month Gas 

Cost, including 

Taxes and 

Miscellaneous 

Charges 

Average Monthly 

Gas Cost, including 

Taxes and 

Miscellaneous 

Charges 

Minimum $ 92.87 $ 7.75 $ 99.25 $ 8.28 

Mean $406.11 $34.00 $432.68 $36.22 

Median $398.49 $33.27 $424.80 $35.47 

Maximum $916.46 $76.01 $973.01 $80.71 

Standard 

deviation $165.68 $13.85 $175.99 $14.71 

Coefficient 

of 

variation 

40.8% 40.8% 40.7% 40.7% 

*Outlier and early homes excluded 

9
Table N-11. Descriptive Statistics on Combined Utility Bill, July 2003 S June 2004 (n=109*) 

Statistic 

Total 12-Month 

Combined 

Utility Bill, 

no Taxes or 

Miscellaneous 

Charges 

Average Monthly 

Combined 

Utility Bill, 

no Taxes or 

Miscellaneous 

Charges 

Total 12-Month 

Combined 

Utility Bill, 

including Taxes and 

Miscellaneous 

Charges 

Average Monthly 

Combined 

Utility Bill, 

including Taxes and 

Miscellaneous 

Charges 

Minimum $ 198.88 $ 16.59 $ 250.52 $720.91 

Mean $1,586.87 $132.54 $1,727.99 $144.32 

Median $1,490.03 $124.23 $1,608.33 $134.20 

Maximum $3,462.68 $288.90 $3,687.10 $307.63 

Standard 

deviation $ 711.54 $ 59.39 $ 772.99 $ 64.51 

Coefficient 

of 

variation

 44.8% 44.8% 44.7% 44.7% 

*Outlier and early homes excluded 

Table N-12. Descriptive Statistics on Average Utility Costs per Square Foot, 

July 2003SJune 2004, Excluding Taxes and Miscellaneous Charges (n=109*) 

Statistic 

Average Monthly 

Electricity Cost/ft2 

Average Monthly 

Gas Cost/ft2 

Average Combined 

Monthly Utility Bill /ft2 

Minimum $.001 $.003 $.006 

Mean $.033 $.011 $.044 

Median $.030 $.011 $.041 

Maximum $.085 $.031 $.108 

Standard 

deviation $.017 $.005 $.020 

Coefficient 

of variation 51.5% 45.5% 45.5% 

*Outlier and early homes excluded 

10
 

Table N-13. Comparative Descriptive Statistics on Electricity Cost, July 2003SJune 2004, 

for Homes in the SheaHomes and Comparison Communities 

Development Statistic 

Total 

12-Month 

Electricity 

Cost, 

no Taxes or 

Miscellaneous 

Charges 

Average 

Monthly 

Electricity 

Cost, 

no Taxes or 

Miscellaneous 

Charges 

Total 

12-Month 

Electricity 

Cost, 

including 

Taxes and 

Miscellaneous 

Charges 

Average 

Monthly 

Electricity 

Cost, including 

Taxes and 

Miscellaneous 

Charges 

Minimum $ 35.76 $ 2.99 $ 76.35 $ 6.39 

Mean $1,092.91 $ 91.24 $1,202.81 $100.41 

SheaHomes 

(n=81*) 

Median $ 993.78 $ 82.54 $1,150.83 $ 95.76 

Maximum $2,738.94 $229.09 $2,998.04 $250.77 

Standard 

deviation $ 550.41 $ 45.96 $ 600.87 $ 50.18 

Coefficient 

of 

variation 

50.4% 50.4% 50.0% 50.0% 

Minimum $ 489.31 $ 40.74 $ 539.95 $ 44.96 

Mean $1,434.87 $119.67 $1,562.98 $130.34 

Comparison 

community 

(n=28*) 

Median $1,336.24 $111.46 $1,378.74 $115.12 

Maximum $2,775.19 $231.88 $3,037.61 $253.80 

Standard 

deviation $ 698.74 $ 58.29 $ 766.64 $ 63.96 

Coefficient 

of 

variation 

48.7% 48.7% 49.1% 49.1% 

*Outlier and early homes excluded 

11
Table N-14. Comparative Descriptive Statistics on Gas Cost, July 2003SJune 2004, 

for Homes in the SheaHomes and Comparison Communities 

Development Statistic 

Total 

12-Month 

Gas Cost, 

no Taxes or 

Miscellaneous 

Charges 

Average 

Monthly 

Gas Cost, 

no Taxes or 

Miscellaneous 

Charges 

Total 

12-Month 

Gas Cost, 

including 

Taxes and 

Miscellaneous 

Charges 

Average 

Monthly 

Gas Cost, 

including 

Taxes and 

Miscellaneous 

Charges 

Minimum $ 92.87 $ 7.75 $ 99.25 $ 8.28 

Mean $378.83 $31.72 $403.67 $33.81 

SheaHomes 

(n=81*) 

Median $369.57 $30.99 $393.93 $33.04 

Maximum $744.61 $62.37 $791.95 $66.35 

Standard 

deviation $143.40 $12.00 $152.32 $12.75 

Coefficient 

of variation 37.9% 37.9% 37.7% 37.7% 

Minimum $187.30 $15.69 $199.90 $16.75 

Mean $485.05 $40.58 $516.61 $43.22 

Comparison 

community 

(n=28*) 

Median $496.52 $41.49 $528.90 $44.20 

Maximum $916.46 $76.01 $973.01 $80.71 

Standard 

deviation $200.43 $16.72 $212.86 $17.76 

Coefficient 

of variation 41.3% 41.3% 41.1% 41.1% 

*Outlier and early homes excluded 

12
Table N-15. Comparative Descriptive Statistics on Combined Utility Bill, July 2003SJune 2004, for

Homes in the SheaHomes and Comparison Communities

Development Statistic 

Total 

12-Month 

Combined 

Utility Bill, no 

Taxes or 

Miscellaneous 

Charges 

Average 

Monthly 

Combined 

Utility Bill, 

no Taxes or 

Miscellaneous 

Charges 

Total 

12-Month 

Combined 

Utility Bill, 

including 

Taxes and 

Miscellaneous 

Charges 

Average 

Monthly 

Combined 

Utility Bill, 

including 

Taxes and 

Miscellaneous 

Charges 

Minimum $ 198.88 $ 16.59 $ 250.52 $ 20.91 

Mean $1,471.74 $122.96 $1,606.48 $134.21 

SheaHomes Median $1,397.09 $116.89 $1,523.02 $127.42 

(n=81*) Maximum $3,168.80 $265.08 $3,456.15 $289.12 

Standard 

deviation $ 638.40 $ 53.32 $ 694.37 $ 57.99 

Coefficient 

of variation 43.4% 43.4% 43.2% 43.2% 

Minimum $ 760.85 $ 63.37 $ 832.00 $ 69.29 

Mean $1,919.91 $160.25 $2,079.50 $173.57 

Comparison 

community 

(n=28*) 

Median $1,828.40 $152.82 $1,854.83 $155.06 

Maximum $3,462.68 $288.90 $3,687.10 $307.63 

Standard 

deviation $ 814.11 $ 67.91 $ 888.28 $ 4.10 

Coefficient 

of variation 42.4% 42.4% 42.7% 42.7% 

*Outlier and early homes excluded 

13
Table N-16. Comparative Descriptive Statistics on Average Utility Costs per Square Foot, 

July 2003SJune 2004, for Homes in the SheaHomes and Comparison Communities, 

Excluding Taxes and Miscellaneous Charges

Development Statistic 

Average Monthly 

Electricity 

Cost/ft2 

Average 

Monthly Gas 

Cost/ft2 

Average Monthly 

Combined Utility 

Bill/ft2 

Minimum $.001 $.003 $.006 

Mean $.029 $.010 $.040 

SheaHomes Median $.027 $.010 $.038 

(n=81*) Maximum $.080 $.018 $.093 

Standard 

deviation $.015 $.004 $.017 

Coefficient of 

variation 51.7% 40.0% 42.5% 

Minimum $.016 $.006 $.025 

Mean $.043 $.015 $.057 

Comparison 

community 

(n=28*) 

Median $.040 $.014 $.054 

Maximum $.085 $.031 $.108 

Standard 

deviation $.020 $.006 $.024 

Coefficient of 

variation 46.5% 40.0% 42.1% 

*Outlier and early homes excluded 

14
 

Table N-17. Comparative Descriptive Statistics on Electricity Cost, July 2003SJune 2004, for 

Homes in the SheaHomes Communities with and without Solar PV Systems

Home 

Category Statistic 

Total 

12-Month 

Electricity 

Cost, 

no Taxes or 

Miscellaneous 

Charges 

Average 

Monthly 

Electricity 

Cost, 

no Taxes or 

Miscellaneous 

Charges 

Total 

12-Month 

Electricity 

Cost, 

including 

Taxes and 

Miscellaneous 

Charges 

Average 

Monthly 

Electricity 

Cost, including 

Taxes and 

Miscellaneous 

Charges 

With PV 

(n=37*) 

Minimum $ 35.76 $ 2.99 $ 76.35 $ 6.39 

Mean $ 922.32 $ 77.00 $1,015.38 $ 84.77 

Median $ 924.49 $ 77.19 $1,017.14 $ 84.92 

Maximum $2,010.24 $167.71 $2,203.71 $183.84 

Standard 

deviation $ 509.46 $ 42.50 $ 555.80 $ 46.37 

Coefficient 

of variation 55.2% 55.2% 54.7% 54.7% 

Without PV 

(n=44*) 

Minimum $ 439.69 $ 36.64 $ 485.20 $ 40.44 

Mean $1,236.37 $103.21 $1,360.43 $113.56 

Median $1,175.95 $ 98.18 $1,292.66 $107.92 

Maximum $2,738.94 $229.09 $2,998.04 $250.76 

Standard 

deviation $ 547.93 $ 45.80 $ 597.85 $ 49.97 

Coefficient 

of variation 44.4% 44.4% 44.0% 44.0% 

*Outlier and early homes excluded 

15
Table N-18. Comparative Descriptive Statistics on Gas Cost, July 2003SJune 2004, for 

Homes in the SheaHomes Communities with and without Solar PV Systems

Home 

Category Statistic 

Total 

12-Month 

Gas Cost, 

no Taxes or 

Miscellaneous 

Charges 

Average 

Monthly 

Gas Cost, 

no Taxes or 

Miscellaneous 

Charges 

Total 

12-Month 

Gas Cost, 

including 

Taxes and 

Miscellaneous 

Charges 

Average 

Monthly 

Gas Cost, 

including 

Taxes and 

Miscellaneous 

Charges 

With PV 

(n=37*) 

Minimum $ 92.87 $ 7.75 $ 99.25 $ 8.28 

Mean $352.52 $29.53 $375.72 $31.48 

Median $318.58 $26.73 $339.93 $28.52 

Maximum $684.47 $57.18 $727.62 $60.79 

Standard 

deviation $144.14 $12.06 $153.09 $12.81 

Coefficient 

of variation 40.9% 40.9% 40.7% 40.7% 

Without PV 

(n=44*) 

Minimum $118.55 $ 9.91 $126.59 $10.58 

Mean $400.95 $33.56 $427.17 $35.76 

Median $409.29 $34.28 $436.02 $36.52 

Maximum $744.61 $62.37 $791.95 $66.35 

Standard 

deviation $140.60 $11.77 $149.37 $12.51 

Coefficient 

of variation 35.1% 35.1% 35.0% 35.0% 

*Outlier and early homes excluded 

16
 

Table N-19. Comparative Descriptive Statistics on Combined Utility Bill, July 2003 S June 2004, for

Homes in the SheaHomes Communities with and without Solar PV Systems

Home 

Category Statistic 

Total 

12-Month 

Combined 

Utility Bill, no 

Taxes or 

Miscellaneous 

Charges 

Average 

Monthly 

Combined 

Utility Bill, 

no Taxes or 

Miscellaneous 

Charges 

Total 

12-Month 

Combined 

Utility Bill, 

including 

Taxes and 

Miscellaneous 

Charges 

Average 

Monthly 

Combined 

Utility Bill, 

including 

Taxes and 

Miscellaneous 

Charges 

With PV 

(n=37*) 

Minimum $ 198.88 $ 16.59 $ 250.52 $ 0.91 

Mean $1,274.84 $106.53 $1,391.10 $116.25 

Median $1,169.29 $ 97.92 $1,277.45 $106.72 

Maximum $2,626.12 $219.24 $2,856.74 $238.49 

Standard 

deviation $ 602.92 $ 50.31 $ 654.66 $ 54.62 

Coefficient 

of variation 47.3% 47.3% 47.0% 47.0% 

Without PV 

(n=44*) 

Minimum $ 674.66 $ 56.23 $ 735.60 $ 61.32 

Mean $1,637.31 $136.77 $1,787.60 $149.32 

Median $1,560.13 $130.11 $1,753.35 $146.22 

Maximum $3,168.80 $265.08 $3,456.15 $289.12 

Standard 

deviation $ 626.50 $ 52.37 $ 681.71 $ 56.99 

Coefficient 

of variation 38.3% 38.3% 38.2% 38.2% 

*Outlier and early homes excluded 

17
Table N-20. Comparative Descriptive Statistics on Average Utility Costs per Square Foot, 

July 2003SJune 2004, for Homes in the SheaHomes Communities with and without Solar PV

Systems, Excluding Taxes and Miscellaneous Charges

Home Category Statistic 

Average Monthly 

Electricity 

Cost/ft2 

Average 

Monthly Gas 

Cost/ft2 

Average Monthly 

Combined Utility 

Bill/ft2 

Minimum $.001 $.003 $.006 

Mean $.025 $.010 $.035 

With PV (n=37*) Median $.025 $.009 $.035 

Maximum $.065 $.018 $.079 

Standard 

deviation $.014 $.004 $.016 

Coefficient 

of variation 56.0% 40.0% 45.7% 

Minimum $.012 $.003 $.018 

Mean $.033 $.011 $.044 

Without PV Median $.031 $.012 $.043 

(n=44*) Maximum $.080 $.017 $.093 

Standard 

deviation $.014 $.004 $.016 

Coefficient 

of variation 42.4% 36.4% 36.4% 

*Outlier and early homes excluded 

18
Appendix P

Histograms of 12-Month Utility Data for

All Homes Combined

Cited in Chapter 20 

P-1
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 305.28 

Mean = 664

N = 109.00

50 250 450 650 850 1050 1250 1450

150 350 550 750 950 1150 1350 1550

Consumption Interval (kWh) 

Figure P-1. Frequency Distribution of Average Monthly Electricity Consumption, July 2003-June 

2004, for All Homes in the SheaHomes and Comparison Communities.

2
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .10 

Mean = .22 

N = 109.00 

.02 .09 .17 .24 .32 .39 .47 .54

.06 .13 .21 .28 .36 .43 .51 .58

Consumption Interval (kWh/sqft) 

Figure P-2. Frequency Distribution of Average Monthly Electricity Consumption/ft2, 

July 2003-June 2004, for All Homes in the SheaHomes and Comparison Communities. 

3
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 55.32 

Mean = 108 

N = 109.00 

8 41 73 106 138 171 203 236

24 57 89 122 154 187 219 252

Cost Interval ($) 

Figure P-3. Frequency Distribution of Average Monthly Electricity Cost, Including Taxes and

Miscellaneous Charges, July 2003-June 2004, for All Homes in the SheaHomes and Comparison

Communities.

4
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 50.70 

Mean = 99 

N = 109.00 

8 41 73 106 138 171 203 236

24 57 89 122 154 187 219 252

Cost Interval ($) 

Figure P-4. Frequency Distribution of Average Monthly Electricity Cost, Excluding Taxes and

Miscellaneous Charges, July 2003-June 2004, for All Homes in the SheaHomes and Comparison

Communities.

5
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .036 

N = 109.00 

.003 .016 .028 .041 .053 .066 .078 .091 

.009 .022 .034 .047 .059 .072 .084 .097 

Cost Interval ($/sqft) 

Figure P-5. Frequency Distribution of Average Monthly Electricity Cost/ft2, Including Taxes and

Miscellaneous Charges, July 2003-June 2004, for All Homes in the SheaHomes and Comparison

Communities.

6
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .033 

N = 109.00 

.003 .016 .028 .041 .053 .066 .078 .091 

.009 .022 .034 .047 .059 .072 .084 .097 

Cost Interval ($/sqft) 

Figure P-6. Frequency Distribution of Average Monthly Electricity Cost/ft2, Excluding Taxes and

Miscellaneous Charges, July 2003-June 2004, for All Homes in the SheaHomes and Comparison

Communities.

7
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 13.36 

Mean = 35.1 

N = 109.00 

2.5 12.5 22.5 32.5 42.5 52.5 62.5 72.5 

7.5 17.5 27.5 37.5 47.5 57.5 67.5 77.5 

Consumption Interval (therms) 

Figure P-7. Frequency Distribution of Average Monthly Gas Consumption, July 2003-June 2004, 

for All Homes in the SheaHomes and Comparison Communities.

8
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0117 

N = 109.00 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Consumption Interval (Therms/sqft)) 

Figure P-8. Frequency Distribution of Average Monthly Gas Consumption/ft2, July 2003-June 2004, 

for All Homes in the SheaHomes and Comparison Communities. 

9
30 

25 

20 

15 

10 

5 

0 

Std. Dev = 14.71 

Mean = 36.2 

N = 109.00 

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2 

Cost Interval ($) 

Figure P-9. Frequency Distribution of Average Monthly Gas Cost, Including Taxes and

Miscellaneous Charges, July 2003-June 2004, for All Homes in the SheaHomes and Comparison

Communities.

10
30 

20 

10 

0 

Std. Dev = 13.85 

Mean = 34.0 

N = 109.00 

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2 

Cost Interval ($) 

Figure P-10. Frequency Distribution of Average Monthly Gas Cost, Excluding Taxes and

Miscellaneous Charges, July 2003-June 2004, for All Homes in the SheaHomes and Comparison

Communities.

11
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .01 

Mean = .0121 

N = 109.00 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Cost Interval ($/sqft) 

Figure P-11. Frequency Distribution of Average Monthly Gas Cost/ft2, Including Taxes and

Miscellaneous Charges, July 2003-June 2004, for All Homes in the SheaHomes and Comparison

Communities.

12
30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0114 

N = 109.00 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Cost Interval($/sqft) 

Figure P-12. Frequency Distribution of Average Monthly Gas Cost/ft2, Excluding Taxes and

Miscellaneous Charges, July 2003-June 2004, for All Homes in the SheaHomes and Comparison

Communities.

13
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 2096984 

Mean = 5755367

N = 109.00

437500 3937500 7437500 10937500

2187500 5687500 9187500 12687500

Consumption Interval (Btu) 

Figure P-13. Frequency Distribution of Average Monthly Combined Energy Consumption, July 

2003-June 2004, for All Homes in the SheaHomes and Comparison Communities.

14
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 728.03 

Mean = 1923.6 

N = 109.00 

156.3 1406.3 2656.3 3906.3 

781.3 2031.3 3281.3 4531.3 

Consumption Interval (Btu/sqft) 

Figure P-14. Frequency Distribution of Average Monthly Combined Energy Consumption/ft2, July 

2003-June 2004, for All Homes in the SheaHomes and Comparison Communities.

15
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 64.51 

Mean = 144 

N = 109.00 

10 50 90 130 170 210 250 290

30 70 110 150 190 230 270 310

Cost Interval ($) 

Figure P-15. Frequency Distribution of Average Monthly Combined Utility Bill, Including Taxes and

Miscellaneous Charges, July 2003-June 2004, for All Homes in the SheaHomes and Comparison

Communities.

16
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 59.39 

Mean = 133 

N = 109.00 

10 50 90 130 170 210 250 290

30 70 110 150 190 230 270 310

Cost Interval ($) 

Figure P-16. Frequency Distribution of Average Monthly Combined Utility Bill, Excluding Taxes 

and Miscellaneous Charges, July 2003-June 2004, for All Homes in the SheaHomes and 

Comparison Communities. 

17
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .048 

N = 109.00 

.004 .020 .037 .053 .069 .085 .102 .118

.012 .028 .045 .061 .077 .093 .110 .126

Cost Interval ($/sqft) 

Figure P-17. Frequency Distribution of Average Monthly Combined Utility Bill/ft2, Including Taxes 

and Miscellaneous Charges, July 2003-June 2004, for All Homes in the SheaHomes and 

Comparison Communities. 

18
Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .044 

N = 109.00 

.004 .020 .037 .053 .069 .085 .102 .118

.012 .028 .045 .061 .077 .093 .110 .126

Cost Interval ($/sqft) 

Figure P-18. Frequency Distribution of Average Monthly Combined Utility Bill/ft2, Excluding Taxes 

and Miscellaneous Charges, July 2003-June 2004, for All Homes in the SheaHomes and 

Comparison Communities. 

19
Appendix Q

Histograms of 12-Month Utility Data for 

SheaHomes and Comparison Homes

Cited in Chapter 20 

Q-1
(a) 

145 339 533 727 920 1114 1308 1502

Consumption Interval (kWh)

(b) 

48 242 436 630 823 1017 1211 1405 

145 339 533 727 920 1114 1308 1502 

Consumption Interval (kWh) 

Figure Q-1. Frequency Distribution of Average Monthly Electricity Consumption, July 2003-June 

2004, for (a) SheaHomes and (b) Comparison Homes. 

24248 630436 823 1017 1211 1405

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 278.97 

Mean = 620 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 345.27 

Mean = 793 

N = 28.00 

2
(a) 

.54.47.39.32.24.17.09.02 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .09 

Mean = .20 

N = 81.00 

.06 .13 .21 .28 .36 .43 .51 .58 

Consumption Interval (kWh/sqft) 

(b) 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .12 

Mean = .28 

N = 28.00 

.02 .09 .17 .24 .32 .39 .47 .54 

.06 .13 .21 .28 .36 .43 .51 .58 

Consumption Interval (kWh/sqft) 

Figure Q-2. Frequency Distribution of Average Monthly Electricity Consumption/ft2

, July 2003-June 

2004, for (a) SheaHomes and (b) Comparison Homes. 

3
(a) 

24 57 89 122 154 187 219 252

Cost Interval ($)

(b) 

8 41 73 106 138 171 203 236 

24 57 89 122 154 187 219 252 

Cost Interval ($) 

Figure Q-3. Frequency Distribution of Average Monthly Electricity Cost, Including Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) SheaHomes and (b) Comparison Homes. 

10673418 138 171 236203

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 50.18 

Mean = 100 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 63.96 

Mean = 130 

N = 28.00 

4
10673418 138 171 236203

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 45.96 

Mean = 91 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 58.29 

Mean = 120 

N = 28.00 

(a) 

24 57 89 122 154 187 219 252 

Cost Interval ($) 

(b) 

8 41 73 106 138 171 203 236 

24 57 89 122 154 187 219 252 

Cost Interval ($) 

Figure Q-4. Frequency Distribution of Average Monthly Electricity Cost, Excluding Taxes and

Miscellaneous Charges, July 2003-June 2004, for (a) SheaHomes and (b) Comparison Homes.

5
(a) 

.009 .022 .034 .047 .059 .072 .084 .097

Cost Interval ($/sqft) 

(b) 

.003 .016 .028 .041 .053 .066 .078 .091 

.009 .022 .034 .047 .059 .072 .084 .097 

Cost Interval ($/sqft) 

Figure Q-5. Frequency Distribution of Average Monthly Electricity Cost/ft2

, Including Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) SheaHomes and (b) Comparison Homes. 

.003 .016 .028 .041 .053 .066 .078 .091

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .032 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .046 

N = 28.00 

6
(a) 

.009 .022 .034 .047 .059 .072 .084 .097

Cost Interval ($)

(b) 

.003 .016 .028 .041 .053 .066 .078 .091 

.009 .022 .034 .047 .059 .072 .084 .097 

Cost Interval ($) 

Figure Q-6. Frequency Distribution of Average Monthly Electricity Cost/ft2

, Excluding Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) SheaHomes and (b) Comparison Homes. 

.003 .016 .028 .041 .053 .066 .078 .091

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .01 

Mean = .029 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .043 

N = 28.00 

7
2.5 12.5 22.5 32.5 42.5 52.5 62.5 72.5

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 11.65 

Mean = 32.8 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 15.90 

Mean = 41.6 

N = 28.00 

(a) 

7.5 17.5 27.5 37.5 47.5 57.5 67.5 77.5 

Consumption Interval (Therms) 

(b) 

2.5 12.5 22.5 32.5 42.5 52.5 62.5 72.5 

7.5 17.5 27.5 37.5 47.5 57.5 67.5 77.5 

Consumption Interval (Therms) 

Figure Q-7. Frequency Distribution of Average Monthly Gas Consumption, July 2003-June 2004, for 

(a) SheaHomes and (b) Comparison Homes. 

8
(a) 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387

Consumption Interval (Therms/sqft))

(b) 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Consumption Interval (Therms/sqft) 

Figure Q-8. Frequency Distribution of Average Monthly Gas Consumption/ft2

, July 2003-June 2004, 

for (a) SheaHomes and (b) Comparison Homes. 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0106 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .01 

Mean = .0149 

N = 28.00 

9
(a) 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2

Cost Interval ($)

(b) 

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2 

Cost Interval ($) 

Figure Q-9. Frequency Distribution of Average Monthly Gas Cost, Including Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) SheaHomes and (b) Comparison Homes. 

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 12.75 

Mean = 33.8 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 17.76 

Mean = 43.2 

N = 28.00 

10
(a) 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2

Cost Interval ($)

(b) 

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2 

Cost Interval ($) 

Figure Q-10. Frequency Distribution of Average Monthly Gas Cost, Excluding Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) SheaHomes and (b) Comparison Homes. 

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 12.00 

Mean = 31.7 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 16.72 

Mean = 40.6 

N = 28.00 

11
(a) 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387

Cost Interval ($/sqft)

(b) 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Cost Interval ($/sqft) 

Figure Q-11. Frequency Distribution of Average Monthly Gas Cost/ft2

, Including Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) SheaHomes and (b) Comparison Homes. 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0110 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .01 

Mean = .0155 

N = 28.00 

12
(a) 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387

Cost Interval ($/sqft)

(b) 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Cost Interval ($/sqft) 

Figure Q-12. Frequency Distribution of Average Monthly Gas Cost/ft2

, Excluding Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) SheaHomes and (b) Comparison Homes. 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0103 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .01 

Mean = .0146 

N = 28.00 

13
(a) 

437500 3937500 7437500 10937500

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 1849335 

Mean = 5377979 

N = 81.00 

2187500 5687500 9187500 12687500

Consumption Interval (Btu)

(b) 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 2406788 

Mean = 6847096 

N = 28.00 

437500 3937500 7437500 10937500

2187500 5687500 9187500 12687500

Consumption Interval (Btu) 

Figure Q-13. Frequency Distribution of Average Monthly Combined Energy Consumption, July 

2003-June 2004, for (a) SheaHomes and (b) Comparison Homes. 

14
(a) 

156.3 1406.3 2656.3 3906.3

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 577.40 

Mean = 1742.5 

N = 81.00 

781.3 2031.3 3281.3 4531.3 

Consumption Interval (Btu/sqft) 

(b) 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 865.61 

Mean = 2447.4 

N = 28.00 

156.3 1406.3 2656.3 3906.3 

781.3 2031.3 3281.3 4531.3 

Consumption Interval (Btu/sqft) 

Figure Q-14. Frequency Distribution of Average Monthly Combined Energy Consumption/ft2

, July 

2003-June 2004, for (a) SheaHomes and (b) Comparison Homes. 

15
(a) 

30 70 110 150 190 230 270 310

Cost Interval ($)

(b) 

10 50 90 130 170 210 250 290 

30 70 110 150 190 230 270 310 

Cost Interval ($) 

Figure Q-15. Frequency Distribution of Average Monthly Combined Utility Bill, Including Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) SheaHomes and (b) Comparison Homes. 

130905010 170 210 290250

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 57.99 

Mean = 134 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 74.10 

Mean = 174 

N = 28.00 

16
(a) 

30 70 110 150 190 230 270 310

Cost Interval ($) 

(b) 

10 50 90 130 170 210 250 290 

30 70 110 150 190 230 270 310 

Cost Interval ($) 

Figure Q-16. Frequency Distribution of Average Monthly Combined Utility Bill, Excluding Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) SheaHomes and (b) Comparison Homes. 

130905010 170 210 290250

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 53.32 

Mean = 123 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 67.91 

Mean = 160 

N = 28.00 

17
(a) 

.012 .028 .045 .061 .077 .093 .110 .126

Cost Interval ($/sqft)

(b) 

.004 .020 .037 .053 .069 .085 .102 .118 

.012 .028 .045 .061 .077 .093 .110 .126 

Cost Interval ($/sqft) 

Figure Q-17. Frequency Distribution of Average Monthly Combined Utility Bill/ft2

, Including Taxes 

and Miscellaneous Charges, July 2003-June 2004, for (a) SheaHomes and (b) Comparison Homes. 

.004 .020 .037 .053 .069 .085 .102 .118

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .043 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .03 

Mean = .062 

N = 28.00 

18
(a) 

.012 .028 .045 .061 .077 .093 .110 .126

Cost Interval ($/sqft)

(b) 

.004 .020 .037 .053 .069 .085 .102 .118 

.012 .028 .045 .061 .077 .093 .110 .126 

Cost Interval ($/sqft) 

Figure Q-18. Frequency Distribution of Average Monthly Combined Utility Bill/ft2

, Excluding Taxes 

and Miscellaneous Charges, July 2003-June 2004, for (a) SheaHomes and (b) Comparison Homes. 

.004 .020 .037 .053 .069 .085 .102 .118

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .040 

N = 81.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .057 

N = 28.00 

19
Appendix R

Histograms of 12-Month Utility Data for 

PV and SEE Homes

Cited in Chapter 20 

R-1
(a) 

150 350 550 750 950 1150 1350 1550

Consumption Interval (kWh)

(b) 

50 250 450 650 850 1050 1250 1450 

150 350 550 750 950 1150 1350 1550 

Consumption Interval (kWh) 

Figure R-1. Frequency Distribution of Average Monthly Electricity Consumption, July 2003-June 

2004, for (a) PV Homes and (b) SEE Homes.

25050 650450 850 1050 1250 1450

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 267.50 

Mean = 532 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 269.37 

Mean = 694 

N = 44.00 

2
(a) 

.54.47.39.32.24.17.09.02 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .09 

Mean = .17 

N = 37.00 

.06 .13 .21 .28 .36 .43 .51 .58 

Consumption Interval (kWh/sqft) 

(b) 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .08 

Mean = .22 

N = 44.00 

.02 .09 .17 .24 .32 .39 .47 .54 

.06 .13 .21 .28 .36 .43 .51 .58 

Consumption Interval (kWh/sqft) 

Figure R-2. Frequency Distribution of Average Monthly Electricity Consumption/ft2

, July 2003-June 

2004, for (a) PV Homes and (b) SEE Homes. 

3
(a) 

24 57 89 122 154 187 219 252

Cost Interval ($)

(b) 

8 41 73 106 138 171 203 236 

24 57 89 122 154 187 219 252 

Cost Interval ($) 

Figure R-3. Frequency Distribution of Average Monthly Electricity Cost, Including Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes and (b) SEE Homes. 

23620317113810673418 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 46.37 

Mean = 85 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 49.97 

Mean = 114 

N = 44.00 

4
(a) 

24 57 89 122 154 187 219 252

Cost Interval ($)

(b) 

8 41 73 106 138 171 203 236 

24 57 89 122 154 187 219 252 

Cost Interval ($) 

Figure R-4. Frequency Distribution of Average Monthly Electricity Cost, Excluding Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes and (b) SEE Homes. 

13810673418 236203171

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 42.50 

Mean = 77 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 45.80 

Mean = 103 

N = 44.00 

5
(a) 

.009 .022 .034 .047 .059 .072 .084 .097

Cost Interval ($/sqft)

(b) 

.003 .016 .028 .041 .053 .066 .078 .091 

.009 .022 .034 .047 .059 .072 .084 .097 

Cost Interval ($/sqft) 

Figure R-5. Frequency Distribution of Average Monthly Electricity Cost/ft2

, Including Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes and (b) SEE Homes. 

.003 .016 .028 .041 .053 .066 .078 .091

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .028 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .036 

N = 44.00 

6
(a) 

.009 .022 .034 .047 .059 .072 .084 .097

Cost Interval ($/sqft)

(b) 

.003 .016 .028 .041 .053 .066 .078 .091 

.009 .022 .034 .047 .059 .072 .084 .097 

Cost Interval ($/sqft) 

Figure R-6. Frequency Distribution of Average Monthly Electricity Cost/ft2

, Excluding Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes and (b) SEE Homes. 

.003 .016 .028 .041 .053 .066 .078 .091

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .01 

Mean = .025 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .01 

Mean = .033 

N = 44.00 

7
(a) 

7.5 17.5 27.5 37.5 47.5 57.5 67.5 77.5

Consumption Interval (Therms)

(b) 

2.5 12.5 22.5 32.5 42.5 52.5 62.5 72.5 

7.5 17.5 27.5 37.5 47.5 57.5 67.5 77.5 

Consumption Interval (Therms) 

Figure R-7. Frequency Distribution of Average Monthly Gas Consumption, July 2003-June 2004, 

for (a) PV Homes and (b) SEE Homes.

2.5 12.5 22.5 32.5 42.5 52.5 62.5 72.5

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 11.71 

Mean = 30.7 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 11.41 

Mean = 34.6 

N = 44.00 

8
(a) 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387

Consumption Interval (Therms/sqft)

(b) 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Consumption Interval (Therms/sqft) 

Figure R-8. Frequency Distribution of Average Monthly Gas Consumption/ft2

, July 2003-June 2004, 

for (a) PV Homes and (b) SEE Homes. 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0100 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0112 

N = 44.00 

9
(a) 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2

Cost Interval ($)

(b) 

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2 

Cost Interval ($) 

Figure R-9. Frequency Distribution of Average Monthly Gas Cost, Including Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes and (b) SEE Homes. 

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 12.81 

Mean = 31.5 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 12.51 

Mean = 35.8 

N = 44.00 

10
(a) 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2

Cost Interval ($)

(b) 

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2 

Cost Interval ($) 

Figure R-10. Frequency Distribution of Average Monthly Gas Cost, Excluding Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes and (b) SEE Homes. 

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 12.06 

Mean = 29.5 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 11.77 

Mean = 33.6 

N = 44.00 

11
(a) 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0103 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0115 

N = 44.00 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Cost Interval ($/sqft) 

(b) 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Cost Interval ($/sqft) 

Figure R-11. Frequency Distribution of Average Monthly Gas Cost/ft2

, Including Taxes and

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes and (b) SEE Homes.

12
(a) 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387

Cost Interval ($/sqft)

(b) 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Cost Interval ($/sqft) 

Figure R-12. Frequency Distribution of Average Monthly Gas Cost/ft2

, Excluding Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes and (b) SEE Homes. 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0097 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0108 

N = 44.00 

13
437500 3937500 7437500 10937500

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 1839918 

Mean = 4861411 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 1762378 

Mean = 5812366 

N = 44.00 

(a) 

2187500 5687500 9187500 12687500

Consumption Interval (Btu)

(b) 

437500 3937500 7437500 10937500

2187500 5687500 9187500 12687500

Consumption Interval (Btu) 

Figure R-13. Frequency Distribution of Average Monthly Combined Energy Consumption, July 

2003-June 2004, for (a) PV Homes and (b) SEE Homes.

14
(a) 

156.3 1406.3 2656.3 3906.3

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 587.97 

Mean = 1593.3 

N = 37.00 

781.3 2031.3 3281.3 4531.3 

Consumption Interval (Btu/sqft) 

(b) 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 543.66 

Mean = 1868.0 

N = 44.00 

156.3 1406.3 2656.3 3906.3 

781.3 2031.3 3281.3 4531.3 

Consumption Interval (Btu) 

Figure R-14. Frequency Distribution of Average Monthly Combined Energy Consumption/ft2

, July 

2003-June 2004, for (a) PV Homes and (b) SEE Homes.

15
(a) 

30 70 110 150 190 230 270 310

Cost Interval ($)

(b) 

10 50 90 130 170 210 250 290 

30 70 110 150 190 230 270 310 

Cost Interval ($) 

Figure R-15. Frequency Distribution of Average Monthly Combined Utility Bill, Including Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes and (b) SEE Homes. 

130905010 170 210 290250

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 54.62 

Mean = 116 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 56.99 

Mean = 149 

N = 44.00 

16
(a) 

30 70 110 150 190 230 270 310

Cost Interval ($)

(b) 

10 50 90 130 170 210 250 290 

30 70 110 150 190 230 270 310 

Cost Interval ($) 

Figure R-16. Frequency Distribution of Average Monthly Combined Utility Bill, Excluding Taxes 

and Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes and (b) SEE Homes. 

130905010 170 210 290250

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 50.31 

Mean = 107 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 52.37 

Mean = 137 

N = 44.00 

17
(a) 

.012 .028 .045 .061 .077 .093 .110 .126

Cost Interval ($/sqft)

(b) 

.004 .020 .037 .053 .069 .085 .102 .118 

.012 .028 .045 .061 .077 .093 .110 .126 

Cost Interval ($/sqft) 

Figure R-17. Frequency Distribution of Average Monthly Combined Utility Bill/ft2

, Including Taxes 

and Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes and (b) SEE Homes. 

.004 .020 .037 .053 .069 .085 .102 .118

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .038 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .048 

N = 44.00 

18
(a) 

.012 .028 .045 .061 .077 .093 .110 .126

Cost Interval ($/sqft)

(b) 

.004 .020 .037 .053 .069 .085 .102 .118 

.012 .028 .045 .061 .077 .093 .110 .126 

Cost Interval ($/sqft) 

Figure R-18. Frequency Distribution of Average Monthly Combined Utility Bill/ft2

, Excluding Taxes 

and Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes and (b) SEE Homes. 

.004 .020 .037 .053 .069 .085 .102 .118

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .035 

N = 37.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .044 

N = 44.00 

19
Appendix S 

Descriptive Statistics on Total and Average Electricity Consumption 

and Total and Average Gas Consumption with and without Selected 

Equipment, by Categories of Homes (12-Month Data) 

Cited in Chapter 20 

S-1
(a) 

150 350 550 750 950 1150 1350 1550

Consumption Interval (kWh)

(b) 

50 250 450 650 850 1050 1250 1450 

150 350 550 750 950 1150 1350 1550 

Consumption Interval (kWh) 

Figure S-1. Frequency Distribution of Average Monthly Electricity Consumption, July 2003-June 

2004, for (a) PV Homes with 1.2-kW Systems and (b) PV Homes with 2.4-kW Systems. 

25050 650450 850 1050 1250 1450

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 258.45 

Mean = 573 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 222.03 

Mean = 318 

N = 6.00 

2
(a) 

.54.47.39.32.24.17.09.02 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .09 

Mean = .19 

N = 31.00 

.06 .13 .21 .28 .36 .43 .51 .58 

Consumption Interval (kWh/sqft) 

(b) 

Frequency 

30.0 

25.0 

20.0 

15.0 

10.0 

5.0 

0.0 

Std. Dev = .07 

Mean = .10 

N = 6.00 

.02 .09 .17 .24 .32 .39 .47 .54 

.06 .13 .21 .28 .36 .43 .51 .58 

Consumption Interval (kWh/sqft) 

Figure S-2. Frequency Distribution of Average Monthly Electricity Consumption/ft2

, July 2003-June 

2004, for (a) PV Homes with 1.2-kW Systems and (b) PV Homes with 2.4-kW Systems. 

3
(a) 

24 57 89 122 154 187 219 252

Cost Interval ($)

(b)

8 41 73 106 138 171 203 236 

24 57 89 122 154 187 219 252 

Cost Interval ($) 

Figure S-3. Frequency Distribution of Average Monthly Electricity Cost, Including Taxes and

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes with 1.2-kW Systems and (b) PV

Homes with 2.4-kW Systems.

10673418 138 171 236203

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 45.73 

Mean = 92 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 33.83 

Mean = 49 

N = 6.00 

4
(a) 

24 57 89 122 154 187 219 252

Cost Interval ($)

(b) 

8 41 73 106 138 171 203 236 

24 57 89 122 154 187 219 252 

Cost Interval ($) 

Figure S-4. Frequency Distribution of Average Monthly Electricity Cost, Excluding Taxes and

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes with 1.2-kW Systems and (b) PV

Homes with 2.4-kW Systems.

10673418 138 171 236203

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 41.76 

Mean = 83 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 31.70 

Mean = 44 

N = 6.00 

5
(a) 

.003 .016 .028 .041 .053 .066 .078 .091

.009 .022 .034 .047 .059 .072 .084 .097

Cost Interval ($/sqft) 

(b) 

.003 .016 .028 .041 .053 .066 .078 .091 

.009 .022 .034 .047 .059 .072 .084 .097 

Cost Interval ($/sqft) 

Figure S-5. Frequency Distribution of Average Monthly Electricity Cost/ft2

, Including Taxes and

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes with 1.2-kW Systems and (b) PV

Homes with 2.4-kW Systems.

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .030 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .01 

Mean = .016 

N = 6.00 

6
(a) 

.009 .022 .034 .047 .059 .072 .084 .097

Cost Interval ($/sqft) 

(b) 

.003 .016 .028 .041 .053 .066 .078 .091 

.009 .022 .034 .047 .059 .072 .084 .097 

Cost Interval ($/sqft) 

Figure S-6. Frequency Distribution of Average Monthly Electricity Cost/ft2

, Excluding Taxes and

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes with 1.2-kW Systems and (b) PV

Homes with 2.4-kW Systems.

.003 .016 .028 .041 .053 .066 .078 .091

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .01 

Mean = .027 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .01 

Mean = .014 

N = 6.00 

7
(a) 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2

Consumption Interval (Therms)

(b) 

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2 

Consumption Interval (Therms) 

Figure S-7. Frequency Distribution of Average Monthly Gas Consumption, July 2003-June 2004, for 

(a) PV Homes with 1.2-kW Systems and (b) PV Homes with 2.4-kW Systems. 

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 12.06 

Mean = 30.7 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 10.68 

Mean = 30.3 

N = 6.00 

8
(a) 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387

Consumption Interval (Therms/sqft)

(b) 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Consumption Interval (Therms/sqft) 

Figure S-8. Frequency Distribution of Average Monthly Gas Consumption/ft2

, July 2003-June 2004, 

for (a) PV Homes with 1.2-kW Systems and (b) PV Homes with 2.4-kW Systems. 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0101 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0095 

N = 6.00 

9
(a) 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2

Cost Interval ($)

(b) 

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2 

Cost Interval ($) 

Figure S-9. Frequency Distribution of Average Monthly Gas Cost, Including Taxes and

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes with 1.2-kW Systems and (b) PV

Homes with 2.4-kW Systems.

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 13.23 

Mean = 31.6 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 11.48 

Mean = 30.9 

N = 6.00 

10
(a) 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2

Cost Interval ($) 

(b) 

2.8 14.1 25.3 36.6 47.8 59.1 70.3 81.6 

8.4 19.7 30.9 42.2 53.4 64.7 75.9 87.2 

Cost Interval ($) 

Figure S-10. Frequency Distribution of Average Monthly Gas Cost, Excluding Taxes and

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes with 1.2-kW Systems and (b) PV

Homes with 2.4-kW Systems.

14.12.8 25.3 36.6 47.8 59.1 70.3 81.6

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 12.46 

Mean = 29.6 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 10.80 

Mean = 29.0 

N = 6.00 

11
.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0104 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0097 

N = 6.00 

(a) 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Cost Interval ($/sqft) 

(b) 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Cost Interval ($/sqft) 

Figure S-11. Frequency Distribution of Average Monthly Gas Cost/ft2

, Including Taxes and 

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes with 1.2-kW Systems and 

(b) PV Homes with 2.4-kW Systems. 

12
(a) 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Cost Interval ($/sqft) 

(b) 

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362 

.0037 .0087 .0137 .0187 .0237 .0287 .0337 .0387 

Cost Interval ($/sqft) 

Figure S-12. Frequency Distribution of Average Monthly Gas Cost/ft2

, Excluding Taxes and

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes with 1.2-kW Systems and (b) PV

Homes with 2.4-kW Systems.

.0012 .0062 .0112 .0162 .0212 .0262 .0312 .0362

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0098 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .00 

Mean = .0091 

N = 6.00 

13
(a) 

437500 3937500 7437500 10937500

2187500 5687500 9187500 12687500

Consumption Interval (Btu) 

(b) 

437500 3937500 7437500 10937500

2187500 5687500 9187500 12687500

Consumption Interval (Btu) 

Figure S-13. Frequency Distribution of Average Monthly Combined Energy Consumption, July 

2003-June 2004, for (a) PV Homes with 1.2-kW Systems and (b) PV Homes with 2.4-kW Systems. Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 1856477 

Mean = 5009289 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 1690866 

Mean = 4097374 

N = 6.00 

14
(a) 

156.3 1406.3 2656.3 3906.3

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 593.08 

Mean = 1652.1 

N = 31.00 

781.3 2031.3 3281.3 4531.3 

Consumption Interval (Btu/sqft) 

(b) 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 496.41 

Mean = 1289.4 

N = 6.00 

156.3 1406.3 2656.3 3906.3 

781.3 2031.3 3281.3 4531.3 

Consumption Interval (Btu/sqft) 

Figure S-14. Frequency Distribution of Average Monthly Combined Energy Consumption/ft2

, July 

2003-June 2004, for (a) PV Homes with 1.2-kW Systems and (b) PV Homes with 2.4-kW Systems. 

15
(a) 

30 70 110 150 190 230 270 310 

Cost Interval ($) 

(b) 

10 50 90 130 170 210 250 290 

30 70 110 150 190 230 270 310 

Cost Interval ($) 

Figure S-15. Frequency Distribution of Average Monthly Combined Utility Bill, Including Taxes and

Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes with 1.2-kW Systems and (b) PV

Homes with 2.4-kW Systems.

130905010 170 210 290250

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 54.51 

Mean = 123 

N = 31.00 

Frequency 

30.0 

25.0 

20.0 

15.0 

10.0 

5.0 

0.0 

Std. Dev = 42.55 

Mean = 80 

N = 6.00 

16
(a) 

30 70 110 150 190 230 270 310 

Cost Interval ($) 

(b) 

10 50 90 130 170 210 250 290 

30 70 110 150 190 230 270 310 

Cost Interval ($) 

Figure S-16. Frequency Distribution of Average Monthly Combined Utility Bill, Excluding Taxes 

and Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes with 1.2-kW Systems and (b) 

PV Homes with 2.4-kW Systems. 

130905010 170 210 290250

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 50.06 

Mean = 113 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = 39.97 

Mean = 73 

N = 6.00 

17
(a) 

.012 .028 .045 .061 .077 .093 .110 .126 

Cost Interval ($/sqft) 

(b) 

.004 .020 .037 .053 .069 .085 .102 .118 

.012 .028 .045 .061 .077 .093 .110 .126 

Cost Interval ($/sqft) 

Figure S-17. Frequency Distribution of Average Monthly Combined Utility Bill/ft2

, Including Taxes 

and Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes with 1.2-kW Systems and (b) 

PV Homes with 2.4-kW Systems. 

.004 .020 .037 .053 .069 .085 .102 .118

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .041 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .01 

Mean = .025 

N = 6.00 

18
(a) 

.004 .020 .037 .053 .069 .085 .102 .118

.012 .028 .045 .061 .077 .093 .110 .126

Cost Interval ($/sqft) 

(b) 

.005 .025 .045 .065 .085 .105 .125 

.015 .035 .055 .075 .095 .115 

Cost Interval ($/sqft) 

Figure S-18. Frequency Distribution of Average Monthly Combined Utility Bill/ft2

, Excluding Taxes

and Miscellaneous Charges, July 2003-June 2004, for (a) PV Homes with 1.2-kW Systems and

(b) PV Homes with 2.4-kW Systems.

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .02 

Mean = .037 

N = 31.00 

Frequency 

30 

25 

20 

15 

10 

5 

0 

Std. Dev = .01 

Mean = .023 

N = 6.00 

19
Appendix T

Histograms of 12-Month Utility Data for 

Comparison and SEE Homes

Cited in Chapter 20 

T-1
Figure T-1. Frequency Distributions of Average Monthly Electricity Consumption, July 2003-June 

2004, for All Homes in the SheaHomes and Comparison Communities, Relative to Four Equipment 

Ownership Categories: Pools, Hot Tubs, Both, Neither 

2
(a)

(b)

Figure T-2. Frequency Distributions of Average Monthly Electricity Consumption, July 2003-June 

2004, for (a) SheaHomes and (b) Comparison Homes, Relative to Four Equipment Ownership 

Categories. 

3
(a)

(b)

Figure T-3. Frequency Distributions of Average Monthly Electricity Consumption, July 2003-June 

2004, for (a) PV Homes and (b) SEE Homes, Relative to Four Equipment Ownership Categories: 

Pools, Hot Tubs, Both, Neither. 

4
(a)

(b)

Figure T-4. Frequency Distributions of Average Monthly Electricity Consumption, July 2003-June 

2004, for (a) PV Homes with 1.2-kW Systems and (b) PV Homes with 2.4-kW Systems, Relative to 

Four Equipment Ownership Categories. 

5
Figure T-5. Frequency Distributions of Average Monthly Gas Consumption, July 2003-June 2004, 

for All Homes in the SheaHomes and Comparison Communities, Relative to Four Equipment 

Ownership Categories: Pool, Hot Tubs, Both, Neither 

6
(a)

(b)

Figure T-6. Frequency Distributions of Average Monthly Gas Consumption, July 2003-June 2004, 

for (a) SheaHomes and (b) Comparison Homes, Relative to Four Equipment Ownership 

Categories: Pools, Hot Tubs, Both, Neither. 

7
(a)

(b)

Figure T-7. Frequency Distributions of Average Monthly Gas Consumption, July 2003-June 2004, 

for (a) PV Homes and (b) SEE Homes, Relative to Four Equipment Ownership Categories: Pools, 

Hot Tubs, Both, Neither. 

8
(a)

(b)

Figure T-8. Frequency Distributions of Average Monthly Gas Consumption, July 2003-June 2004, 

for (a) PV Homes with 1.2-kW Systems and (b) PV Homes with 2.4-kW Systems, Relative to Four 

Equipment Ownership Categories: Pools, Hot Tubs, Both, Neither. 

9
Appendix U

Descriptive Statistics on Average Monthly Electricity Cost,

Average Monthly Gas Cost, and Average Monthly

Utility Bills with and without Selected Equipment,

by Categories of Homes (12-Month Data)

Cited in Chapter 20 

U-1
Table U-1. Descriptive Statistics on Average Monthly Electricity Cost 

(Including Taxes and Miscellaneous Charges) for PV Homes, SEE Homes, and 

Comparison Homes with and without Selected Equipment*

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

n 13 11 19 7 

Base case (no special 

equipment) Mean $50.69 $56.14 $94.96 $86.78 

S.D. $30.98 $29.97 $43.69 $39.41 

n 3 3 0 1 

Standalone freezer Mean $120.00 $120.00 – $137.09 

S.D. $50.63 $50.63 – –

n 9 8 11 4 

Two refrigerators Mean $95.98 $105.42 $113.66 $103.73 

S.D. $46.53 $39.48 $58.26 $46.59 

n 0 0 4 0 

Standalone freezer and two 

refrigerators Mean – – $157.51 –

S.D. – – $26.32 –

n 2 1 2 3 

Pool Mean $70.86 $52.84 $111.03 $153.73 

S.D. $25.49 – $37.59 $57.96 

n 0 0 0 1 

Pool and standalone freezer Mean – – – $102.97 

S.D. – – – –

n 3 3 4 1 

Pool and two refrigerators Mean $93.13 $93.13 $126.10 $101.71 

S.D. $46.86 $46.86 $66.07 –

n 2 2 3 3 

Hot tub Mean $116.33 $116.33 $151.32 $162.21 

S.D. $18.66 $18.66 $38.08 $60.54 

2
Table U-1. Descriptive Statistics on Average Monthly Electricity Cost 

(Including Taxes and Miscellaneous Charges) for PV Homes, SEE Homes, 

and Comparison Homes with and without Selected Equipment*

(continued) 

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

n 2 2 0 0 

Hot tub and two 

refrigerators Mean $167.42 $167.42 – –

S.D. $14.55 $14.55 – –

n 0 0 0 2 

Pool and hot tub Mean – – – $205.76 

S.D. – – – $67.95 

n 0 0 0 2 

Pool, hot tub, and 

standalone freezer Mean – – – $146.95 

S.D. – – – $120.79 

n 2 1 1 2 

Pool, hot tub, and two 

refrigerators Mean $91.55 $119.08 $131.86 $228.32 

S.D. $38.93 – – $22.90 

*“Early” and outlier homes omitted 

**Information regarding the presence of refrigerators and freezers is missing for some homes in these categories 

3
Table U-2. Descriptive Statistics on Average Monthly Electricity Cost per Square Foot 

(Including Taxes and Miscellaneous Charges) for 

PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

No special features 

n 13 11 19 7 

Mean $.018 $.020 $.030 $.034 

S.D. $.011 $.011 $.012 $.016 

Standalone freezer 

n 3 3 0 1 

Mean $.038 $.038 – $.049 

S.D. $.018 $.018 – – 

Two refrigerators 

n 9 8 11 4 

Mean $.033 $.036 $.037 $.035 

S.D. $.017 $.015 $.020 $.017 

Standalone freezer and 

two refrigerators 

n 0 0 4 0 

Mean – – $.048 – 

S.D. – – $.005 – 

Pool 

n 2 1 2 3 

Mean $.024 $.018 $.037 $.052 

S.D. $.007 - $.011 $.024 

Pool and standalone 

freezer 

n 0 0 0 1 

Mean – – – $.037 

S.D. – – – – 

Pool and two 

refrigerators 

n 3 3 4 1 

Mean $.029 $.029 $.040 $.041 

S.D. $.015 $.015 $.022 – 

Hot tub 

n 2 2 3 3 

Mean $.036 $.036 $.047 $.054 

S.D. $.001 $.001 $.009 $.015 

4
Table U-2. Descriptive Statistics on Average Monthly Electricity Cost per Square Foot 

(Including Taxes and Miscellaneous Charges) for 

PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

(continued)

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

n 2 2 0 0 

Hot tub and two 

refrigerators Mean $.051 $.051 – – 

S.D. $.002 $.002 – – 

n 0 0 0 2 

Pool and hot tub Mean – – – $.060 

S.D. – – – $.017 

n 0 0 0 2 

Pool, hot tub, and 

standalone freezer Mean – – – $.058 

S.D. – – – $.051 

n 2 1 1 2 

Pool, hot tub, and two 

refrigerators Mean $.028 $.039 $.042 $.086 

S.D. $.015 – – $.001 

*“Early” and outlier homes omitted 

**Information regarding the presence of refrigerators and freezers is missing for some homes in these categories 

5
Table U-3. Descriptive Statistics on Average Monthly Electricity Cost

(Excluding Taxes and Miscellaneous Charges) for 

PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

No special features n 13 11 19 7 

Mean $45.81 $50.98 $85.95 $78.90 

S.D. $28.56 $27.31 $39.98 $36.01 

Standalone freezer n 3 3 0 1 

Mean $109.26 $109.26 – $124.86 

S.D. $46.32 $46.32 – –

Two refrigerators n 9 8 11 4 

Mean $87.20 $95.93 $103.49 $101.27 

S.D. $42.75 $36.12 $53.33 $43.49 

Standalone freezer and two 

refrigerators 

n 0 0 4 0 

Mean – – $143.58 –

S.D. – – $24.12 –

Pool 

n 2 1 2 3 

Mean $64.37 $47.92 $101.04 $137.36 

S.D. $23.26 – $34.37 $49.97 

Pool and standalone freezer n 0 0 0 1 

Mean – – – $93.66 

S.D. – – – –

Pool and two refrigerators n 3 3 4 1 

Mean $84.72 $84.72 $114.86 $92.51 

S.D. $42.75 $42.75 $60.50 –

Hot tub 

n 2 2 3 3 

Mean $105.89 $105.89 $137.92 $149.95 

S.D. $17.05 $17.05 $34.91 $58.87 

6
Table U-3. Descriptive Statistics on Average Monthly Electricity Cost

(Excluding Taxes and Miscellaneous Charges) for 

PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

(continued)

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

n 2 2 0 0 

Hot tub and two 

refrigerators Mean $152.65 $152.65 – –

S.D. $13.30 $13.30 – –

n 0 0 0 2 

Pool and hot tub Mean – – – $187.82 

S.D. – – – $62.31 

n 0 0 0 2 

Pool, hot tub, and 

standalone freezer Mean – – – $134.02 

S.D. – – – $110.56 

n 2 1 1 2 

Pool, hot tub, and two 

refrigerators Mean $83.25 $108.39 $120.09 $208.47 

S.D. $35.55 – – $21.02 

*“Early” and outlier homes omitted 

**Information regarding the presence of refrigerators and freezers is missing for some homes in these categories 

7
Table U-4. Descriptive Statistics on Average Monthly Electricity Cost per Square Foot 

(Excluding Taxes and Miscellaneous Charges) for 

PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

No special features 

n 13 11 19 7 

Mean $.015 $.018 $.028 $.031 

S.D. $.010 $.010 $.011 $.015 

Standalone freezer 

n 3 3 0 1 

Mean $.034 $.034 – $.044 

S.D. $.017 $.017 – – 

Two refrigerators 

n 9 8 11 4 

Mean $.030 $.032 $.034 $.034 

S.D. $.016 $.014 $.018 $.015 

Standalone freezer and two 

refrigerators 

n 0 0 4 0 

Mean – – $.044 – 

S.D. – – $.005 – 

Pool 

n 2 1 2 3 

Mean $.022 $.016 $.034 $.047 

S.D. $.008 – $.010 $.021 

Pool and standalone freezer 

n 0 0 0 1 

Mean – – – $.033 

S.D. – – – – 

Pool and two refrigerators 

n 3 3 4 1 

Mean $.027 $.027 $.036 $.037 

S.D. $.013 $.013 $.020 – 

Hot tub 

n 2 2 3 3 

Mean $.032 $.032 $.043 $.050 

S.D. $.001 $.001 $.009 $.015 

8
Table U-4. Descriptive Statistics on Average Monthly Electricity Cost per Square Foot 

(Excluding Taxes and Miscellaneous Charges) for 

PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

(continued)

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

n 2 2 0 0 

Hot tub and two 

refrigerators Mean $.047 $.047 – – 

S.D. $.002 $.002 – – 

n 0 0 0 2 

Pool and hot tub Mean – – – $.055 

S.D. – – – $.016 

n 0 0 0 2 

Pool, hot tub, and 

standalone freezer Mean – – – $.053 

S.D. – – – $.046 

n 2 1 1 2 

Pool, hot tub, and two 

refrigerators Mean $.026 $.035 $.038 $.079 

S.D. $.014 – – $.001 

*“Early” and outlier homes omitted 

**Information regarding the presence of refrigerators and freezers is missing for some homes in these categories 

9
Table U-5. Descriptive Statistics on Average Monthly Gas Cost

(Including Taxes and Miscellaneous Charges) for 

PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

No special features 

n 13 11 19 7 

Mean $21.77 $21.41 $32.79 $41.14 

S.D. $6.29 $5.43 $9.81 $16.84 

Standalone freezer 

n 3 3 0 1 

Mean $44.40 $44.40 – $47.10 

S.D. $12.17 $12.17 – – 

Two refrigerators 

n 9 8 11 4 

Mean $34.43 $35.49 $34.82 $41.15 

S.D. $10.05 $10.20 $15.19 $15.90 

Standalone freezer and two 

refrigerators 

n 0 0 4 0 

Mean – – $43.75 – 

S.D. – – $15.29 – 

Pool 

n 2 1 2 3 

Mean $29.63 $14.49 $47.20 $45.37 

S.D. $21.42 – $0.80 $6.95 

Pool and standalone freezer 

n 0 0 0 1 

Mean – – – $32.62 

S.D. – – – – 

Pool and two refrigerators 

n 3 3 4 1 

Mean $35.11 $35.11 $31.97 $19.77 

S.D. $10.87 $10.87 $17.59 – 

Hot tub 

n 2 2 3 3 

Mean $36.04 $36.04 $44.82 $42.41 

S.D. $24.82 $24.82 $5.30 $30.889 

10
Table U-5. Descriptive Statistics on Average Monthly Gas Cost

(Including Taxes and Miscellaneous Charges) for 

PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

(continued)

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

n 2 2 0 0 

Hot tub and two 

refrigerators Mean $46.50 $46.50 – – 

S.D. $20.21 $20.21 – – 

n 0 0 0 2 

Pool and hot tub Mean – – – $48.69 

S.D. – – – $29.75 

n 0 0 0 2 

Pool, hot tub, and 

standalone freezer Mean – – – $45.21 

S.D. – – – $21.09 

n 2 1 1 2 

Pool, hot tub, and two 

refrigerators Mean $42.07 $41.73 $35.66 $68.30 

S.D. $30.49 – – $17.54 

*“Early” and outlier homes omitted 

**Information regarding the presence of refrigerators and freezers is missing for some homes in these categories 

11
Table U-6. Descriptive Statistics on Average Monthly Gas Cost per Square Foot 

(Including Taxes and Miscellaneous Charges) for 

PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

No special features 

n 13 11 19 7 

Mean $.008 $.007 $.011 $.016 

S.D. $.002 $.002 $.004 $.007 

Standalone freezer 

n 3 3 0 1 

Mean $.014 $.014 – $.017 

S.D. $.005 $.005 – – 

Two refrigerators 

n 9 8 11 4 

Mean $.012 $.012 $.011 $.014 

S.D. $.003 $.003 $.004 $.006 

Standalone freezer and 

two refrigerators 

n 0 0 4 0 

Mean – – $.013 – 

S.D. – – $.004 – 

Pool 

n 2 1 2 3 

Mean $.010 $.005 $.016 $.015 

S.D. $.007 – $.001 $.0005 

Pool and standalone 

freezer 

n 0 0 0 1 

Mean – – – $.012 

S.D. – – – – 

Pool and two refrigerators 

n 3 3 4 1 

Mean $.011 $.011 $.010 $.008 

S.D. $.004 $.004 $.006 – 

Hot tub 

n 2 2 3 3 

Mean $.012 $.012 $.014 $.014 

S.D. $.010 $.010 $.001 $.009 

12
Table U-6. Descriptive Statistics on Average Monthly Gas Cost per Square Foot 

(Including Taxes and Miscellaneous Charges) for 

PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

(continued)

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

n 2 2 0 0 

Hot tub and two 

refrigerators Mean $.014 $.014 – – 

S.D. $.006 $.006 – – 

n 0 0 0 2 

Pool and hot tub Mean – – – $.015 

S.D. – – – $.009 

n 0 0 0 2 

Pool, hot tub, and 

standalone freezer Mean – – – $.017 

S.D. – – – $.009 

n 2 1 1 2 

Pool, hot tub, and two 

refrigerators Mean $.013 $.014 $.011 $.026 

S.D. $.001 – – $.009 

*“Early” and outlier homes omitted 

**Information regarding the presence of refrigerators and freezers is missing for some homes in these categories 

13
Table U-7. Descriptive Statistics on Average Monthly Gas Cost

(Excluding Taxes and Miscellaneous Charges)

for PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

No special features n 13 11 19 7 

Mean $20.39 $20.05 $30.77 $38.62 

S.D. $5.90 $5.09 $9.23 $15.85 

Standalone freezer n 3 3 0 1 

Mean $41.68 $41.68 – $44.21 

S.D. $11.48 $11.48 – – 

Two refrigerators n 9 8 11 4 

Mean $32.30 $33.30 $32.68 $38.66 

S.D. $9.47 $9.60 $14.30 $14.96 

Standalone freezer and two 

refrigerators 

n 0 0 4 0 

Mean – – $41.06 – 

S.D. – – $14.40 – 

Pool n 2 1 2 3 

Mean $27.81 $13.56 $44.32 $42.59 

S.D. $20.14 - $0.77 $6.54 

Pool and standalone freezer n 0 0 0 1 

Mean – – – $30.57 

S.D. – – – – 

Pool and two refrigerators n 3 3 4 1 

Mean $32.95 $32.95 $30.01 $18.51 

S.D. $10.23 $10.23 $16.57 – 

Hot tub 

n 2 2 3 3 

Mean $33.85 $33.85 $42.13 $39.73 

S.D. $23.38 $23.38 $5.01 $28.97 

14
Table U-7. Descriptive Statistics on Average Monthly Gas Cost

(Excluding Taxes and Miscellaneous Charges)

for PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

(continued)

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

n 2 2 0 0 

Hot tub and two 

refrigerators Mean $43.71 $43.71 – – 

S.D. $19.06 $19.06 – – 

n 0 0 0 2 

Pool and hot tub Mean – – – $45.75 

S.D. – – – $28.07 

n 0 0 0 2 

Pool, hot tub, and 

standalone freezer Mean – – – $42.45 

S.D. – – – $19.90 

n 2 1 1 2 

Pool, hot tub, and two 

refrigerators Mean $39.52 $39.24 $33.46 $64.26 

S.D. $0.40 – – $16.61 

*“Early” and outlier homes omitted 

**Information regarding the presence of refrigerators and freezers is missing for some homes in these categories 

15
Table U-8. Descriptive Statistics on Average Monthly Electricity Cost per Square Foot 

(Excluding Taxes and Miscellaneous Charges)

for PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

No special features 

n 13 11 19 7 

Mean $.007 $.007 $.010 $.015 

S.D. $.002 $.002 $.003 $.006 

Standalone freezer 

n 3 3 0 1 

Mean $.013 $.013 – $.017 

S.D. $.004 $.004 – – 

Two refrigerators 

n 9 8 11 4 

Mean $.011 $.011 $.010 $.013 

S.D. $.003 $.0 $.004 $.006 

Standalone freezer and two 

refrigerators 

n 0 0 4 0 

Mean – – $.012 – 

S.D. – – $.004 – 

Pool 

n 2 1 2 3 

Mean $.009 $.005 $.015 $.014 

S.D. $.006 – $.001 $.0004 

Pool and standalone freezer 

n 0 0 0 1 

Mean – – – $.011 

S.D. – – – – 

Pool and two refrigerators 

n 3 3 4 1 

Mean $.010 $.010 $.009 $.007 

S.D. $.004 $.004 $.005 – 

Hot tub 

n 2 2 3 3 

Mean $.011 $.011 $.013 $.013 

S.D. $.009 $.009 $.001 $.008 

16
Table U-8. Descriptive Statistics on Average Monthly Electricity Cost per Square Foot 

(Excluding Taxes and Miscellaneous Charges)

for PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

(continued)

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

Hot tub and two 

refrigerators 

n 2 2 0 0 

Mean $.013 $.013 – – 

S.D. $.005 $.005 – – 

n 0 0 0 2 

Pool and hot tub Mean – – – $.014 

S.D. – – – $.009 

n 0 0 0 2 

Pool, hot tub, and 

standalone freezer Mean – – – $.016 

S.D. – – – $.009 

n 2 1 1 2 

Pool, hot tub, and two 

refrigerators Mean $.012 $.013 $.011 $.025 

S.D. $.001 – – $.008 

*“Early” and outlier homes omitted 

**Information regarding the presence of refrigerators and freezers is missing for some homes in these categories 

17
Table U-9. Descriptive Statistics on Average Monthly Combined Utility Bill 

(Including Taxes and Miscellaneous Charges)

for PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

No special features 

n 13 11 19 7 

Mean $72.46 $77.56 $127.75 $127.92 

S.D. $31.81 $30.29 $45.64 $42.18 

Standalone freezer 

n 3 3 0 1 

Mean $164.40 $164.40 – $184.18 

S.D. $62.78 $62.78 – – 

Two refrigerators 

n 9 8 11 4 

Mean $130.41 $140.90 $148.49 $144.88 

S.D. $53.46 $46.19 $68.29 $61.71 

Standalone freezer and two 

refrigerators 

n 0 0 4 0 

Mean – – $201.26 – 

S.D. – – $36.29 – 

Pool 

n 2 1 2 3 

Mean $100.50 $67.32 $158.23 $199.10 

S.D. $46.92 - $36.79 $55.93 

Pool and standalone freezer 

n 0 0 0 1 

Mean – – – $135.60 

S.D. – – – – 

Pool and two refrigerators 

n 3 3 4 1 

Mean $128.24 $128.24 $158.07 $121.48 

S.D. $36.14 $36.14 $80.48 – 

Hot tub 

n 2 2 3 3 

Mean $152.37 $152.37 $196.14 $204.62 

S.D. $6.16 $6.16 $43.34 $90.66 

18
Table U-9. Descriptive Statistics on Average Monthly Combined Utility Bill 

(Including Taxes and Miscellaneous Charges)

for PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

(continued)

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

n 2 2 0 0 

Hot tub and two 

refrigerators Mean $213.92 $213.92 – – 

S.D. $34.76 $34.76 – – 

n 0 0 0 2 

Pool and hot tub Mean – – – $254.44 

S.D. – – – $38.19 

n 0 0 0 2 

Pool, hot tub, and 

standalone freezer Mean – – – $192.17 

S.D. – – – $141.88 

n 2 1 1 2 

Pool, hot tub, and two 

refrigerators Mean $133.62 $160.81 $167.51 $296.62 

S.D. $38.45 – – $5.35 

*“Early” and outlier homes omitted 

**Information regarding the presence of refrigerators and freezers is missing for some homes in these categories 

19
Table U-10. Descriptive Statistics on Average Monthly Combined Utility Bill per Square Foot 

(Including Taxes and Miscellaneous Charges) for PV Homes, SEE Homes, and Comparison Homes 

with and without Selected Equipment*

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

n 13 11 19 7 

No special features Mean $.025 $.026 $.041 $.050 

S.D. $.011 $.011 $.013 $.018 

n 3 3 0 1 

Standalone freezer Mean $.052 $.052 – $.065 

S.D. $.023 $.023 – – 

n 9 8 11 4 

Two refrigerators Mean $.044 $.048 $.048 $.049 

S.D. $.020 $.017 $.023 $.023 

n 0 0 4 0 

Standalone freezer and 

two refrigerators Mean – – $.061 – 

S.D. – – $.006 – 

n 2 1 2 3 

Pool Mean $.034 $.024 $.054 $.067 

S.D. $.014 – $.010 $.024 

n 0 0 0 1 

Pool and standalone 

freezer Mean – – – $.048 

S.D. – – – – 

n 3 3 4 1 

Pool and two refrigerators Mean $.040 $.040 $.050 $.049 

S.D. $.011 $.011 $.027 – 

Hot tub 

n 2 2 3 3 

Mean $.048 $.048 $.062 $.067 

S.D. $.010 $.010 $.010 $.023 

20
Table U-10. Descriptive Statistics on Average Monthly Combined Utility Bill per Square Foot

(Including Taxes and Miscellaneous Charges) for PV Homes, SEE Homes, and Comparison

Homes with and without Selected Equipment*

(continued)

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

n 2 2 0 0 

Hot tub and two 

refrigerators Mean $.065 $.065 – – 

S.D. $.008 $.008 – – 

n 0 0 0 2 

Pool and hot tub Mean – – – $.075 

S.D. – – – $.008 

n 0 0 0 2 

Pool, hot tub, and 

standalone freezer Mean – – – $.075 

S.D. – – – $.060 

n 2 1 1 2 

Pool, hot tub, and two 

refrigerators Mean $.041 $.052 $.053 $.112 

S.D. $.017 – – $.008 

*“Early” and outlier homes omitted 

**Information regarding the presence of refrigerators and freezers is missing for some homes in these categories 

21
Table U-11. Descriptive Statistics on Average Monthly Combined Utility Bill 

(Excluding Taxes and Miscellaneous Charges)

for PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

No special features 

n 13 11 19 7 

Mean $66.20 $71.04 $116.72 $117.52 

S.D. $29.39 $27.62 $41.67 $38.68 

Standalone freezer 

n 3 3 0 1 

Mean $150.94 $150.94 – $169.07 

S.D. $57.78 $57.78 – – 

Two refrigerators 

n 9 8 11 4 

Mean $119.50 $129.23 $136.16 $139.94 

S.D. $43.40 $42.45 $62.78 $56.95 

Standalone freezer and two 

refrigerators 

n 0 0 4 0 

Mean – – $184.64 – 

S.D. – – $33.57 – 

Pool 

n 2 1 2 3 

Mean $92.18 $61.49 $145.36 $179.95 

S.D. $43.40 – $33.61 $47.67 

Pool and standalone freezer 

n 0 0 0 1 

Mean – – – $124.23 

S.D. – – – – 

Pool and two refrigerators 

n 3 3 4 1 

Mean $117.66 $117.66 $144.87 $111.02 

S.D. $32.66 $32.66 $74.09 – 

Hot tub 

n 2 2 3 3 

Mean $139.74 $139.74 $180.05 $189.69 

S.D. $6.33 $6.33 $39.87 $87.19 

22
Table U-11. Descriptive Statistics on Average Monthly Combined Utility Bill 

(Excluding Taxes and Miscellaneous Charges)

for PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

(continued)

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

n 2 2 0 0 

Hot tub and two 

refrigerators Mean $196.36 $196.36 – – 

S.D. $32.36 $32.36 – – 

n 0 0 0 2 

Pool and hot tub Mean – – – $233.57 

S.D. – – – $34.24 

n 0 0 0 2 

Pool, hot tub, and 

standalone freezer Mean – – – $176.47 

S.D. – – – $130.46 

n 2 1 1 2 

Pool, hot tub, and two 

refrigerators Mean $122.77 $147.63 $153.55 $272.74 

S.D. $35.15 – – $4.41 

*“Early” and outlier homes omitted 

**Information regarding the presence of refrigerators and freezers is missing for some homes in these categories 

23
Table U-12. Descriptive Statistics on Average Monthly Combined Utility Bill per Square Foot

(Excluding Taxes and Miscellaneous Charges)

for PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

No special features 

n 13 11 19 7 

Mean $.023 $.025 $.038 $.046 

S.D. $.010 $.010 $.012 $.016 

Standalone freezer 

n 3 3 0 1 

Mean $.047 $.047 – $.060 

S.D. $.021 $.021 – – 

Two refrigerators 

n 9 8 11 4 

Mean $.041 $.044 $.044 $.047 

S.D. $.018 $.016 $.021 $.020 

Standalone freezer and two 

refrigerators 

n 0 0 4 0 

Mean – – $.056 – 

S.D. – – $.005 – 

Pool 

n 2 1 2 3 

Mean $.030 $.021 $.049 $.060 

S.D. $.013 – $.009 $.022 

Pool and standalone freezer 

n 0 0 0 1 

Mean – – – $.044 

S.D. – – – – 

Pool and two refrigerators 

n 3 3 4 1 

Mean $.037 $.037 $.046 $.045 

S.D. $.010 $.010 $.025 – 

Hot tub 

n 2 2 3 3 

Mean $.044 $.044 $.056 $.063 

S.D. $.010 $.010 $.009 $.023 

24
Table U-12. Descriptive Statistics on Average Monthly Combined Utility Bill per Square Foot

(Excluding Taxes and Miscellaneous Charges)

for PV Homes, SEE Homes, and Comparison Homes with and without Selected Equipment*

(continued)

Equipment Category Statistic 

PV 

Homes** 

SheaHomes 

with 1.2 PV 

Systems** SEE Homes 

Comparison 

Homes** 

n 2 2 0 0 

Hot tub and two 

refrigerators Mean $.060 $.060 – – 

S.D. $.007 $.007 – – 

n 0 0 0 2 

Pool and hot tub Mean – – – $.068 

S.D. – – – $.007 

n 0 0 0 2 

Pool, hot tub, and 

standalone freezer Mean – – – $.069 

S.D. – – – $.055 

n 2 1 1 2 

Pool, hot tub, and two 

refrigerators Mean $.037 $.048 $.049 $.103 

S.D. $.015 – – $.007 

*“Early” and outlier homes omitted 

**Information regarding the presence of refrigerators and freezers is missing for some homes in these categories 

25
Appendix V

Scatter Diagrams of Average Monthly Electricity

Cost Consumption by Average Monthly Cost for

All Homes in the Study

V-1
Figure V-1. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost (dollars), Excluding Taxes and Miscellaneous Charges,

for All Homes Combined (n=109)

2
Figure V-2. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost (dollars), Excluding Taxes and Miscellaneous Charges,

for Homes in the SheaHomes Communities with PV Systems (n=37)

3
Figure V-3. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost (dollars), Excluding Taxes and Miscellaneous Charges,

for Homes in the SheaHomes Communities without PV Systems (n=44)

4
Figure V-4. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost (dollars), Excluding Taxes and Miscellaneous Charges,

for Homes in the Comparison Community (n=28)

5
Figure V-5. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost (dollars), Including Taxes and Miscellaneous Charges,

for All Homes Combined (n=109)

6
Figure V-6. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost (dollars), Including Taxes and Miscellaneous Charges,

for Homes in the SheaHomes Communities with PV Systems (n=37)

7
Figure V-7. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost (dollars), Including Taxes and Miscellaneous Charges,

for Homes in the SheaHomes Communities without PV Systems (n=44)

8
Figure V-8. Comparison of Average Monthly Electricity Consumption (kWh) and Average

Monthly Electricity Cost (dollars), Including Taxes and Miscellaneous Charges,

for Homes in the Comparison Community (n=28)

9
Figure V-9. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and 

Average Monthly Electricity Cost (dollars)/ft2

, Excluding Taxes and

Miscellaneous Charges, for All Homes Combined (n=109)

10
Figure V-10. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and 

Average Monthly Electricity Cost (dollars)/ft2

, Excluding Taxes and Miscellaneous Charges, for

Homes in the SheaHomes Communities with PV Systems (n=37)

11
Figure V-11. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and 

Average Monthly Electricity Cost (dollars)/ft2

, Excluding Taxes and Miscellaneous Charges, for

Homes in the SheaHomes Communities without PV Systems (n=44)

12
Figure V-12. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and 

Average Monthly Electricity Cost (dollars)/ft2

, Excluding Taxes and Miscellaneous Charges, for

Homes in the Comparison Community (n=28)

13
Figure V-13. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and 

Average Monthly Electricity Cost (dollars)/ft2

, Including Taxes and Miscellaneous Charges, for 

All Homes Combined (n=109)

14
Figure V-14. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and 

Average Monthly Electricity Cost (dollars)/ft2

, Including Taxes and Miscellaneous Charges, for

Homes in the SheaHomes Communities with PV Systems (n=37)

15
Figure V-15. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and Average

Monthly Electricity Cost (dollars)/ft2

, Including Taxes and Miscellaneous Charges, for 

Homes in the SheaHomes Communities without PV Systems (n=44)

16
Figure V-16. Comparison of Average Monthly Electricity Consumption (kWh)/ft2

 and 

Average Monthly Electricity Cost (dollars)/ft2

, Including Taxes and Miscellaneous Charges, for

Homes in the Comparison Community (n=28)

17
Appendix W

Electricity and Gas Consumption 

for 1.2-kW and 2.4-kW Solar PV Systems

in the SheaHomes Communities

Cited in Chapter 21 

W-1
Table W-1. Comparative Descriptive Statistics on Electricity and Natural Gas Consumption,

July 2003SJune 2004, for Homes in the SheaHomes Communities

with Different Sizes of Solar PV Systems

Home 

Category Statistic 

Total 

12-Month 

Electricity 

Consumption 

(kWh) 

Average 

Monthly 

Electricity 

Consumption 

(kWh)

 Total 

12-Month 

Gas 

Consumption 

(therms) 

Average 

Monthly 

Gas 

Consumption 

(therms) 

Minimum 1,880.0 156.6 100.0 8.3 

Homes with 

1.2-kW 

Mean 6,864.2 572.9 366.8 30.7 

Median 6,967.0 581.4 333.0 27.9 

systems 

(n=31*) 

Maximum 12,868.0 1,073.4 678.0 56.6 

Standard 

deviation 3,097.3 258.4 144.3 12.0 

Coefficient 

of variation 45.1% 45.1% 39.2% 39.2% 

Minimum 267.0 22.3 176.0 14.7 

Mean 3,809.5 318.4 361.7 30.3 

Homes with Median 3,972.5 332.0 346.5 29.1 

2.4-kW 

systems 

(n=6*) 

Maximum 68.21 568.9 515.0 43.0 

Standard 

deviation 2,662.6 222.0 127.5 10.7 

Coefficient 

of variation 69.8% 69.8% 35.3% 38.3% 

*Outlier homes excluded 

2
Table W-2. Comparative Descriptive Statistics on Electricity and Natural Gas Consumption per

Square Foot, July 2003SJune 2004, for Homes in the SheaHomes Communities

with Different Sizes of Solar PV Systems

Home 

Category Statistic 

Average Monthly Electricity 

Consumption/ft2

 (kWh) 

Average Monthly Gas 

Consumption/ft2 (therms) 

Minimum .052 .000 

Mean .189 .010 

Homes with 

1.2-kW 

systems 

(n=31*) 

Median .203 .009 

Maximum .415 .020 

Standard 

deviation .085 .004 

Coefficient 

of variation 45.0% 50.0% 

Minimum .009 .010 

Mean .100 .010 

Homes with Median .097 .009 

2.4-kW 

systems 

(n=6*) 

Maximum .185 .010 

Standard 

deviation .071 .003 

Coefficient 

of variation 71.0% 30.0% 

*Outlier homes excluded 

3
 

 

 

Table W-3. Comparative Descriptive Statistics on Electricity Cost, July 2003SJune 2004, for Homes 

in the SheaHomes Communities with Different Sizes of Solar PV Systems 

Home 

Category Statistic 

Total 

12-Month 

Electricity Cost, 

no Taxes or 

Miscellaneous 

Charges 

Average 

Monthly 

Electricity 

Cost, 

no Taxes or 

Miscellaneous 

Charges 

Total 

12-Month 

Electricity 

Cost, 

including 

Taxes and 

Miscellaneous 

Charges 

Average 

Monthly 

Electricity 

Cost, including 

Taxes and 

Miscellaneous 

Charges 

Minimum $ 247.97 $ 20.66 $ 273.59 $ 22.79 

Mean $ 998.42 $ 83.34 $ 1,097.42 $ 91.60 

Homes with 

1.2-kW 

systems 

(n=31*) 

Median $ 993.78 $ 82.54 $91,093.09 $ 90.79 

Maximum $2,010.24 $167.71 $ 2,203.71 $183.84 

Standard 

deviation $ 500.48 $ 41.76 $ 548.06 $ 45.73 

Coefficient 

of variation 50.1% 50.1% 49.9% 49.9% 

Minimum $ 35.76 $ 2.99 $ 76.35 $ 6.39 

Homes with 

2.4-kW 

Mean $529.13 $44.24 $ 591.48 $49.45 

Median $537.09 $44.91 $ 591.98 $49.49 

systems 

(n=6*) 

Maximum $968.90 $80.81 $1,065.73 $88.89 

Standard 

deviation $380.06 $31.70 $ 405.71 $33.83 

Coefficient 

of variation 71.7% 71.7% 68.5% 68.5% 

*Outlier homes excluded 

4
Table W-4. Comparative Descriptive Statistics on Gas Cost, July 2003SJune 2004, for Homes in the

SheaHomes Communities with Different Sizes of Solar PV Systems

Home 

Category Statistic 

Total 

12-Month 

Gas Cost, 

no Taxes or 

Miscellaneous 

Charges 

Average 

Monthly 

Gas Cost, 

no Taxes or 

Miscellaneous 

Charges 

Total 

12-Month 

Gas Cost, 

including 

Taxes and 

Miscellaneous 

Charges 

Average 

Monthly 

Gas Cost, 

including 

Taxes and 

Miscellaneous 

Charges 

Minimum $ 92.87 $ 7.75 $ 99.25 $ 8.28 

Homes with 

1.2-kW 

Mean $353.73 $29.64 $376.98 $31.59 

Median $318.58 $27.73 $339.93 $28.53 

systems 

(n=31*) 

Maximum $684.47 $57.18 $727.62 $60.79 

Standard 

deviation $148.85 $12.46 $158.07 $13.23 

Coefficient 

of variation 42.1% 42.1% 41.9% 41.9% 

Minimum $163.12 $13.61 $174.17 $14.53 

Homes with 

2.4-kW 

systems 

(n=6*) 

Mean $346.30 $28.99 $369.21 $30.91 

Median $328.96 $27.63 $350.93 $29.48 

Maximum $504.22 $42.05 $536.92 $44.78 

Standard 

deviation $128.82 $10.80 $136.98 $11.48 

Coefficient 

of variation 37.2% 37.2% 37.1% 37.1% 

*Outlier homes excluded 

5
Table W-5. Comparative Descriptive Statistics on Combined Utility Bill, July 2003SJune 2004, for

Homes in the SheaHomes Communities with Different Sizes of Solar PV Systems

Home 

Category Statistic 

Total 

12-Month 

Combined 

Utility Bill, no 

Taxes or 

Miscellaneous 

Charges 

Average 

Monthly 

Combined 

Utility Bill, 

no Taxes or 

Miscellaneous 

Charges 

Total 

12-Month 

Combined 

Utility Bill, 

including 

Taxes and 

Miscellaneous 

Charges 

Average 

Monthly 

Combined 

Utility Bill, 

including 

Taxes and 

Miscellaneous 

Charges 

Homes with 

1.2-kW 

systems 

(n=31*) 

Minimum $ 340.84 $ 28.41 $ 372.84 $ 31.07 

Mean $1,352.15 $112.98 $1,474.40 $123.19 

Median $1,347.51 $112.47 $1,472.86 $122.94 

Maximum $3,168.80 $219.24 $2,856.74 $238.49 

Standard 

deviation $ 599.88 $ 50.06 $ 653.21 $ 54.51 

Coefficient 

of variation 44.3% 44.3% 44.2% 44.2% 

Homes with 

2.4-kW 

systems 

(n=6*) 

Minimum $ 198.88 $ 16.59 $ 250.52 $ 20.91 

Mean $ 875.43 $ 73.23 $ 960.69 $ 80.36 

Median $ 957.97 $ 80.15 $1,040.56 $ 87.19 

Maximum $1,473.12 $122.87 $1,602.65 $133.67 

Standard 

deviation $ 479.21 $ 39.97 $ 510.27 $ 42.55 

Coefficient 

of variation 54.6% 54.6% 53.0% 53.0% 

*Outlier homes excluded 

6
Table W-6. Comparative Descriptive Statistics on Average Utility Costs per Square Foot, 

July 2003SJune 2004, for Homes in the SheaHomes Communities with Different Sizes

of Solar PV Systems, Excluding Taxes and Miscellaneous Charges

Home 

Category Statistic 

Average Monthly 

Electricity Cost/ft2 

Average Monthly 

Gas Cost/ft2 

Average Monthly 

Combined Utility Bill/ft2 

Minimum $.007 $.003 $.009 

Homes with 

1.2-kW 

Mean $.027 $.010 $.037 

Median $.029 $.009 $.037 

systems 

(n=31*) 

Maximum $.065 $.018 $.079 

Standard 

deviation $.014 $.004 $.016 

Coefficient 

of 

variation 

51.9% 40.0% 43.2% 

Minimum $.001 $.005 $.006 

Homes with 

2.4-kW 

Mean $.014 $.009 $.023 

Median $.013 $.009 $.024 

systems 

(n=6*) 

Maximum $.026 $.014 $.040 

Standard 

deviation $.010 $.003 $.012 

Coefficient 

of 

variation 

71.4% 33.3% 52.2% 

*Outlier homes excluded 

7
Table W-7. Comparative Descriptive Statistics on Average Utility Costs per Square Foot, 

July 2003SJune 2004, for Homes in the SheaHomes Communities with Different Sizes

of Solar PV Systems, Including Taxes and Miscellaneous Charges

Home 

Category Statistic 

Average Monthly 

Electricity Cost/ft2 

Average Monthly 

Gas Cost/ft2 

Average Monthly 

Combined Utility Bill/ft2 

Minimum $.008 $.003 $.010 

Homes with 

1.2-kW 

Mean $.030 $.010 $.041 

Median $.032 $.009 $.040 

systems 

(n=31*) 

Maximum $.071 $.019 $.086 

Standard 

deviation $.015 $.004 $.018 

Coefficient 

of variation 50.0% 40.0% 43.9% 

Minimum $.002 $.006 $.008 

Homes with 

2.4-kW 

systems 

(n=6*) 

Mean $.016 $.010 $.025 

Median $.014 $.009 $.026 

Maximum $.029 $.015 $.043 

Standard 

deviation $.011 $.003 $.013 

Coefficient 

of variation 68.8% 30.0% 52.0% 

*Outlier homes excluded 

8
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A New Market Paradigm for Zero-Energy Homes: The Comparative 

San Diego Case Study; Volume 1 and Volume 2 (Appendixes) 

5a. CONTRACT NUMBER 

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B.C. Farhar and T.C. Coburn 

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14. ABSTRACT (Maximum 200 Words) 

The housing industry is in flux. Today’s landscape differs from the buyer’s market in San Diego we have studied for 

the past five years. Demand for housing varies in different parts of California and the nation, and interest rates are on 

the upswing. The value of our study does not lie in describing the motivations of today’s new homebuyers, but rather 

it lies in suggesting a conceptually fresh alternative paradigm for the building and marketing of zero-energy homes 

(ZEHs) based on experience. When this paradigm is used, builders, new homebuyers, and utility companies will 

benefit. When appropriately applied to business practice and public policy, this new paradigm will help builders create 

the sustainable communities so necessary for our well-being and that of future generations. 

15. SUBJECT TERMS 

zero-energy home; zeh; SheaHomes; new homebuyers 

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