Reference Publication: Vieira, R., Parker, D., "Energy Use in Attached and Detached Residential Developments: Survey Results", Condensed from FSEC-CR-381-91, Proceedings of the 3rd Visions of Quality Developments, Winter Park, FL., June 1991. Disclaimer: The views and opinions expressed in this article are solely those of the authors and are not intended to represent the views and opinions of the Florida Solar Energy Center. |
Energy Use in Attached and Detached
Residential Developments: Survey Results
Robin
K. Vieira and Danny S. Parker
Florida
Solar Energy Center (FSEC)
FSEC-CR-381-91
Executive Summary
The relationship between land use, density, dwelling types and energy use in Florida has never been comprehensively examined. Few people consider both energy used in housing and energy used for local transportation. Florida state officials and some land planners have called for compact urban growth to reduce traffic congestion and travel distances. However, energy is rarely mentioned in these arguments. Local governments are trying to respond to the state's concern for compact growth. Developers, on the other hand, are concerned with meeting the local regulations. Unfortunately, energy use is seldom considered and there is little data available to guide decision makers.
To meet this deficiency, the Governor's Energy Office funded the Florida Solar Energy Center to study energy use in ten Florida developments built during the 1980s. In order to obtain reasonably sized samples of respondents for a survey, only two distinctly different development types were selected:
1) attached low-rise multifamily housing
2) golf-course community, single-family, executive homes.
Households in ten selected East Central Florida developments were sent the questionnaire; 384 households responded. Matching annual electricity use was obtained for 292 of the respondents. Respondents estimated the total yearly miles driven for each household vehicle. Because this data was collected from only a small number of selected, new developments, the results may not be generalized into representing all detached versus attached dwellings in Florida.
By converting electricity use (for all-electric household respondents)
and mileage to fuel energy consumed, it was found that the detached household
respondents used an estimated average of 2.4 times as much total energy
as attached households. The detached households averaged one more occupant
than the attached households.
The figure below illustrates total estimated energy use by household
size for the attached and detached households. From it we may conclude
that:
- Increased occupancy increases household energy use
- Energy-use-per-occupant decreases with increasing occupancy
- Detached households consumed 150 to 220 million Btus more than attached households of equal occupancy (this represents 85% to 99% greater energy use)
- Detached households consume substantially more electricity that attached households of equal occupancy
- Detached househoulds consume slightly more gasoline than attached households of equal occupancy.
Other highlights of the differences between households include:
- Distances to work, schools and most errand trips were shorter for attached households.
- Forty-seven percent of attached households reported that someone in the household walked or biked to a store or recreation area as opposed to just 17% of detached households.
- Food stores were easily accessible by walking or bicycling according to 42% of attached households as compared to only 4% of detached households.
- Over 25% of attached respondents listed inadequate breezes as a factor in preventing them from opening windows more often as opposed to 10% of detached respondents.
- Noise from traffic was a greater reason for not ventilating attached households as compared to detached households (4.1% to 0%).
- Detached households were more likely to use a clothesline for drying laundry, to have more energy using appliances and more likely to use an electric dishwasher.
- Attached households were more active in managing their thermostats.
Responses to demographic, energy use, transportation and landscaping questions were analyzed through statistical techniques to determine their relationship to estimated miles driven and annual electricity use.
Analysis consistently revealed the following significant relationships to total electricity use:
- Increased floor area strongly relates to increased electricity consumption. Over 70% of the differences in electricity use among respondents were related to conditioned dwelling square footage.
- Households with pool/spa heat pumps showed much higher levels of electricity use.
- The number of hours that households report using pool or spa circulation pumps related to large increases in electricity use.
- Heated water beds were associated with large increases in electricity use.
- Increasing heating thermostat set points corresponded to a moderate increase in electricity use for all-electric homes.
- Increasing cooling thermostat set points correlated to a moderate decrease in electricity use.
- The number of months respondents ventilated related to a large decrease in electricity use.
- Respondents with heat recovery units related to significantly less electricity use.
- Respondents who only occupied households on a seasonal basis had much lower annual electricity use.
- Homes with natural gas used significantly less electricity.
Regression analysis of the transportation data did not show good explanation of the total miles driven. However, the variables which showed a statistically significant relationnship were:
- The number of drivers (the more drivers, the more miles driven).
- School trip miles (the more miles traveled to school, the more miles driven).
- Work trip miles (the more miles traveled to work, the more miles driven).
- College trip miles (the more miles traveled to college, the more miles driven).
- Income; as income increases so do miles driven.
- Households responding that someone walks or bicycles to a park or store corresponded to significantly fewer miles driven.
- Age of household drivers; as age increases, mileage decreases.
The results indicate that per person electricity and transportation use may be reduced by greater household occupancy. In terms of development patterns and zoning laws, it may be energy conserving to allow households to rent out bedrooms, and to have co-housing arrangements where some appliances, e.g., water heaters and refrigerators, could be shared. Transportation energy can be saved by combining erand or school trips by household occupants.
Based on the results, the authors also recommend that municipalities and developments:
- Avoid restrictions calling for minimum floor area
- Allow and encourage solar devices for heating swimming pools and spas
- Provide community pools as an option instead of individual pools and spas
- Allow and encourage the use of clotheslines
- Design homes to make use of natural ventilation
- Provide heat recovery water heater units or other efficient water heating devices
- Locate the development near destinations, particularly schools, colleges and places of work.
Additionally, new land developments should:
- Reduce grass areas; 88% of respondents said they never used their lawns for social or recreational activities, but spent 4 hours per week maintaining them
- Plan for non-drivers. Only one out of 89 children travelled to school independent of an automobile or bus. Only 25% of detached households with non-drivers had someone travel to a store or recreation area on a regular basis without the use of an automobile.
Questions raised by the analysis include:
- How do these results relate to other new Florida developements?
- How do trip distances change over time as new commercial areas follow residential developments?
- How can legal barriers to energy-efficiency, such as seperate zoning and minimum square-footages be removed or improved?
- How can bicycling and walking be encouraged as alternative transportation modes?
- What is the social cost of our present car-dependent transportation system on children and others who do not drive?
- What quantity of energy do residential heat recovery units (desuperheaters) save?
- How much electricity do different pool/spa devices use and what is their impact on the state's total residential energy use?
- What are some acceptable alternatives to turfed lawns for households?
1.0 Background
The relationship between land use, density, dwelling types and energy use has long been an issue of speculation. However, little data has been collected to substantiate these relationships based on measured energy use. Building energy use in four studies was compared by Hanson. They showed a modest decrease in building energy use per square foot of conditioned floor area for larger buildings. All studies were done for northern U.S. climates and only one involved collection of empirical data.
In a theoretical study by Calthorpe and Benson, energy use of a 200 acre townhouse community was calculated at only 56% of the energy use of a 500 acre sprawling single family development. Over half of the savings were due to expected transportation savings. Michael Corbett suggests ideal densities are seven to eight dwelling units per acre for strictly residential areas, five dwelling units per acre for a neighborhood and three to four dwelling units per acre for a town. Corbett argues that although multi-unit dwellings save building materials and reduce building energy use from reduced surfaces for heat loss and heat gain, the savings may be offset by the energy required to transport food into and waste out of highly populated areas. He recommends community gardens interspersed with housing, and using land treatment/enrichment for wastes; solutions unavailable in highly urbanized areas.
There are also other factors influencing energy use, such as land available for shade trees. Shade not only reduces air conditioning use in buildings, but can ameliorate the heat island effect that has been documented to cause as much as a 6oF increase in summer afternoon temperatures in large urban cities.
Another factor is the energy that is embodied in buildings and site development.
By reducing pavement area by 15%, 15.2 x 106 Btu of energy had been calculated
as an annual potential savings for a 2,300-unit development. Energy embodied
in a building has been estimated as ten to fifty percent the amount of
energy used directly in the building over an eighty-year life.
2.0 Developments
To fully describe the relationship of energy use to housing density or type of housing is a complex task. As a beginning, the Florida Solar Energy Center has conducted a written survey and collected one year's worth of electric utility bill from residents of ten East-Central Florida sites developed during the 1980's. The development fit into two distinct categories:
1) Attached low-rise multifamily housing developments, and
2) Golf-course-community, single-family, executive homes.
In the latter case, most of the developments were actually part of planned unit developments that consisted of other building types also, but for this study only single family subdivisions within the planned unit developments were mailed the questionnaire. The extreme disparity of the two residential community types was intentional. We wished to see if significant differences in energy use existed between very divergent community types. The developments were not randomly selected, they were arbitrarily chosen by FSEC to obtain the housing types desired. A description of each development will be presented in the future paper.
3.0 Data Collection
A total of 1,617 surveys were sent out to those residents in each development
listed by Donnerly in their 1990 phone directories. Two hundred-fifty were
returned because of change of address or insufficient address for delivery.
This high return was likely due to the large number of rented multifamily
units. Three hundred eighty-four were completed and returned, with an overall
return rate of those people receiving the survey of 28.1%. Three hundred
forty-two of the respondents gave FSEC permission to obtain electric bills
for the past twelve months (September 1989 - August 1990). Two hundred
ninety-two respondents had a complete year of electricity use data. The
utility data covered the twelve months preceding the survey; September
1989 to August 1990. The values reported for each month represent the billing
month. Thus, on average, the November value should represent electricity
use from mid October to mid November. A complete year's water data was
collected from 214 respondents that were billed individually. Water was
metered collectively for most multifamily complexes and FSEC was able to
obtain that consumption data as well. Approximate per household water use
in the development was developed from this data. This report will focus
on the energy use; a future paper will discuss the water use results.
A copy of the survey questionnaire and a more detailed report are
available from the authors.
4.0 Statistical Significance of Data
The response rates of the questionnaire were 31% for detached units and 16% for attached units that were sent the survey instrument. Of those respondents who received the questionnaire, the response rate was 32% for detached households and 22% for attached households. Whether the respondents are representative of the non-respondents is unknown. Since the information was collected from only a small number of selected, new developments, this information may not be generalized into representing all detached versus attached dwellings.
The limitations of the data presented in this report should be understood when interpreting the reported results. An obvious limitation is the geographical homogenitity of the data source; it comes from the Central Florida area, which may be uncharacteristic of other areas within the state and particularly of other geographical areas in the United States where climatic differences could be expected to make significant differences in the described conclusions.
Because the survey data is self reported and the empirical values (kWh use and water use) are for monthly time periods, lack of correlation between a response and resulting usage does not imply there is no actual effect. In particular, the large variations on energy use makes it statistically difficult to establish significance for factors that result in little systematic change in energy use from one household to another. This problem is even more pronounced when correlating answers to the self-reported mileage data since the data source is necessarily imprecise (estimated mileage vs. actual odometer readings). Moveover, those survey responses that do correlate with the resource use data may show even stronger association if the data sources were improved such as with more households, and more precise measurements.
5.0 Demographics
Table 1 presents the demographics of the respondents. The age category includes every occupant. Although the difference in average is small, the distribution is extremely different as illustrated in Figure 1 and 2. The attached households have a far greater proportion of occupants in the 20 to 35 age group, but a much smaller proportion of occupants under age 20. The average number of occupants was 1.635 for the attached dwellings and was 2.706 for the detached dwellings.
There is a large disparity in the annual household income between the two housing types. Thirty-nine percent of the detached households had incomes in excess of $75,000, whereas only five percent of the attached households fell in that category. The median income fell in the $65,000 - 74,999 category for detached households and only $25,000 - 34,999 for attached households. In comparison, median Florida income for 1988 was $25,000 - 34,999 for all households and only 25.2% had incomes greater than $45,000.
6.0 Electricity Usage
Two developments had natural gas. Respondents using natural gas appliances
were seperated from those that had all-electric homes for the purposes
of analysis. Seasonal occupants were also eliminated for the attached versus
detached analysis since we expected that their inclusion might bias the
various estimates.
Table 1. Demographics of Respondents |
||||||
Total Respondents |
Attached |
Detached |
||||
Respondents |
% |
Respondents |
% |
Respondents |
% |
|
Age |
||||||
| Total Occupants | 826 |
206 |
690 |
|||
| 0-5 years | 42 |
4.7 |
5 |
2.4 |
37 |
5.4 |
6-12 years |
65 |
7.3 |
4 |
1.9 |
61 |
8.8 |
| 13-17 years | 44 |
4.9 |
5 |
2.4 |
39 |
5.7 |
| 18-24 years | 56 |
6.3 |
15 |
7.3 |
41 |
5.9 |
| 25-34 years | 104 |
11.6 |
57 |
27.7 |
47 |
6.8 |
| 35-44 years | 174 |
19.4 |
25 |
12.1 |
149 |
21.6 |
| 45-54 years | 94 |
10.5 |
14 |
6.8 |
80 |
11.6 |
| 55-64 years | 163 |
18.2 |
40 |
19.4 |
123 |
17.8 |
| 65 years and over | 154 |
17.2 |
41 |
19.9 |
113 |
16.4 |
| Average age | 42.3 |
44.2 |
41.7 |
|||
| Household size | ||||||
| Total Respondents | 381 |
126 |
255 |
|||
| One person | 68 |
17.8 |
58 |
46.0 |
10 |
3.9 |
| Two people | 197 |
51.7 |
58 |
46.0 |
139 |
54.5 |
| Three people | 52 |
13.6 |
8 |
6.3 |
44 |
17.3 |
| Four people | 47 |
12.3 |
2 |
1.6 |
45 |
17.6 |
| Five or more people | 17 |
4.5 |
0 |
0 |
17 |
6.7 |
| Average occupancy | 2.352 |
1.635 |
2.706 |
|||
| Family income | ||||||
| Total Respondents | 366 |
126 |
240 |
|||
| Less than $15,000 | 16 |
43.7 |
15 |
11.9 |
1 |
0.4 |
| $15,000-24,999 | 33 |
9.0 |
27 |
21.4 |
6 |
2.5 |
| $25,000-34,999 | 50 |
13.7 |
30 |
23.8 |
20 |
8.3 |
| $35,000-44,999 | 55 |
15.0 |
28 |
22.2 |
27 |
11.3 |
| $45,000-54,999 | 52 |
14.2 |
12 |
9.5 |
40 |
16.7 |
| $55,000-64,999 | 30 |
8.2 |
6 |
4.8 |
24 |
10.0 |
| $65,000-74,999 | 31 |
8.5 |
3 |
2.4 |
28 |
11.7 |
| $75,000 or over | 99 |
27.0 |
5 |
4.0 |
94 |
39.2 |
| Median Range | $45,000-54,999 |
$25,000-34,999 |
$65,000-74,999 |
|||
All electric homes
Average monthly electricity usage per household in the detached dwellings was 2,000 kWh, while only 684 kWh in the attached units. Average monthly electricity usage per occupant was 668 kWh in the detached units and 458 kWh in the attached units. Average monthly electricity usage per square foot was 0.744 kWh and 0.701 kWh respectively in the detached and attached dwellings. Average monthly electricity use per person per square foot was 0.253 kWh and 0.482 kWh in the detached and attached dwellings respectively. These relationships are illustrated in Figures 3 through 6. As shown in Figure 4, there is little difference in electricity use on a per square-foot basis between the two building types. However, because the attached units had fewer square feet per person, the electricity usage per occupant was substantially lower for the attached units as shown in Figure 5. If electricity usage is normalized by both occupancy and floor area, detached households use substantially less than attached dwellings, as shown in Figure 6. This can be explained by the larger household size of detached dwellings as shown in Figure 7. The relationship of electricity use to floor area basis is shown in Figure 8. Analysis indicates that floor area alone may explain over 70% in the variation in annual electricity consumption from one home to another.
Table 2 provides respondents answers to questions on square footage and other dwelling characteristics. The average square footage for attached dwellings is 1,031, whereas the average detached dwelling has 2,396 square feet.
A summary of total annual electricity use by building types is given in Table 3. Figures 9 and 10 show the distinct disparity between attached and detached households. The average usage for all respondents was 16548 kWh/year of 1379 kWh per month. At current electric rates ($0.08/kWh), this indicates an average monthly utility bill of approximately $120. The average per area usage was 8.7 kWh/ft2.
By way of comparison, a 1981 study of 25 existing Palm Beach County houses showed an annual average usage of 24,661 kWh, or 13.04 kWh/ft2, an average occupancy of 4.1, and an average age of 16.1 years[9]. A Florida Power and Light study of 165 customers with an average of 1466 square feet and 2.7 occupants per household had an average annual usage of 13,983 kWh from September 1978 to August 1979 or 9.54 kWh/ft2[10]. Therefore, the present study of new homes represents reduced electricity use per square foot than the studies on older homes.
Most of the differences in electricity use relates to differences in floor area. There is little difference on a kWh/ft2 basis in the frequency of respondents between attached and detached households.
Of particular interest to utilities is how the different types of dwellings affect peak demand. Collecting monthly electrical data does not provide a definitive answer to this question. However, Figure 11 shows that the detached units require more electricity during the peak heating (late December 1989 had the only real cold weather and is represented by the January 1990 billing) and cooling months on a per square foot basis. The differences between attached and detached electrical use disappears during the swing months.
Table 4 shows the distribution of answers to energy related questions. Highlights of differences between dwelling types follow.
- Similar proportions of respondents in each category claimed to open windows some during the various months. However, 26% of attached respondents as opposed to only 10% of detached respondents, listed inadequate breezes as a factor in preventing them from opening windows more often. The relationship of venting and annual electricity use per square foot is shown in Figure 12.
- Noise from traffic was a greater reason for not ventilating in the attached dwellings (4.1% to 0%).
- Attached households were more active in managing their thermostats; 78.7% of attached households turned off their air conditioner/heater or adjusted the thermostat when the dwelling was unoccupied. Only 49.6 % of detached households adjusted their thermostats.
- Fan use varied with housing type. 19.8% of attached households reported never using fans with the air conditioner in use, compared to only 5.6% of detached households. This may, however, be due to fan availability.
- Detached households had more energy using appliances. 26.7% of detached households have more than one refrigerator relative to 3.9% of attached households. 28.7% of detached households have a separate freezer compared to 10.2% of attached households.
- Detached households were more likely to use a clothesline for drying laundry. 21.3% of detached households used a clothesline compared to only 11.8% of attached households.
- Automatic dishwashers were chosen for the dish washing chore much more frequently in the detached dwellings.
Pools and spas are responsible for significant energy use. The distribution of answers on pools and spas are given in Table 5. Over 60% of detached households had a pool, spa or both.
Table 2. Dwelling Characteristics |
||||||
Total Respondents |
Attached |
Detached |
||||
Respondents |
% |
Respondents |
% |
Respondents |
% |
|
| Ownership | ||||||
| Own | 291 |
76.0 |
39 |
30.5 |
252 |
98.8 |
| Rent | 92 |
24.0 |
89 |
69.5 |
3 |
1.2 |
| Total | 383 |
128 |
255 |
|||
| Time in home | ||||||
| Less than 1 year | 45 |
11.7 |
19 |
14.8 |
26 |
10.2 |
| 1 to 3 years | 200 |
52.1 |
73 |
57.0 |
127 |
49.6 |
| 3 to 7 years | 126 |
32.8 |
35 |
27.3 |
91 |
35.5 |
| More than 7 years | 13 |
3.4 |
1 |
0.8 |
12 |
4.7 |
| Residence | ||||||
| Year-round | 360 |
94.7 |
118 |
93.7 |
242 |
95.3 |
| Seasonal | 20 |
5.3 |
8 |
6.3 |
12 |
4.7 |
| Type of residence | ||||||
| Single family - one story |
229 |
59.6 |
0 |
0 |
229 |
89.5 |
Single family - |
26 |
6.8 |
0 |
0 |
26 |
10.2 |
| Townhouse (2-story attached) |
33 |
8.6 |
32 |
25.0 |
1* |
0.4 |
| Top Floor of condominium/apartment | 52 |
13.5 |
52 |
40.6 |
0 |
0 |
| Other (lower) floor of condominium/apartment | 44 |
11.5 |
44 |
34.4 |
0 |
0 |
| Sides having windows | ||||||
|
30 |
8.0 |
30 |
24.2 |
0 |
0 |
|
85 |
22.5 |
76 |
61.3 |
9 |
3.6 |
|
55 |
14.6 |
16 |
12.9 |
39 |
15.4 |
|
207 |
54.9 |
2 |
1.6 |
205 |
81.0 |
| Direction home fronts | ||||||
| North | 58 |
15.4 |
19 |
15.2 |
39 |
15.5 |
| South | 81 |
21.5 |
30 |
24.0 |
51 |
20.3 |
| East | 87 |
23.1 |
31 |
24.8 |
56 |
22.3 |
| West | 76 |
20.2 |
22 |
17.6 |
54 |
21.5 |
| Northeast | 22 |
5.9 |
8 |
6.4 |
14 |
5.6 |
| Southeast | 13 |
3.5 |
5 |
4.0 |
8 |
3.2 |
| Northwest | 14 |
3.7 |
2 |
1.6 |
12 |
4.8 |
| Southwest | 25 |
6.6 |
8 |
6.4 |
17 |
6.8 |
| Construction | ||||||
| Concrete Block | 186 |
51.1 |
69 |
62.2 |
117 |
46.2 |
| Wood Frame | 152 |
41.8 |
30 |
27.0 |
122 |
48.2 |
| Other | 26 |
7.1 |
12 |
10.8 |
14 |
5.5 |
| Wall color | ||||||
| White | 90 |
23.9 |
52 |
41.6 |
38 |
15.1 |
| Other | 287 |
76.1 |
73 |
58.4 |
214 |
84.9 |
| Roofing material | ||||||
| Shingle | 301 |
86.7 |
89 |
91.8 |
212 |
84.8 |
| Metal | 0 |
0 |
0 |
0 |
0 |
0 |
| Built-up | 6 |
1.7 |
1 |
1.0 |
5 |
2.0 |
| Tile | 40 |
11.5 |
7 |
7.2 |
33 |
13.2 |
| Roof color | ||||||
| White | 10 |
2.7 |
1 |
0.9 |
9 |
3.6 |
| Other | 357 |
97.3 |
116 |
99.1 |
241 |
96.4 |
| Square footage | ||||||
| <750 | 11 |
3.1 |
11 |
10.9 |
0 |
0 |
| 750-1249 | 78 |
2.2 |
77 |
76.2 |
1 |
0.4 |
| 1250-1749 | 32 |
9.1 |
10 |
9.9 |
22 |
8.8 |
| 1750-2249 | 90 |
25.6 |
3 |
3.0 |
87 |
34.8 |
| 2250-2749 | 79 |
22.5 |
0 |
0 |
79 |
31.6 |
| 2750-3249 | 41 |
11.6 |
0 |
0 |
41 |
16.4 |
| 3250-3749 | 9 |
2.6 |
0 |
0 |
9 |
3.6 |
>3750 |
11 |
3.1 |
0 |
0 |
11 |
4.4 |
| Average | 2003.2 |
1031.1 |
2395.9 |
|||
| *Respondent had moved to townhouse from single family home. Water and electrical data was for previous residence and so respondent was classified as detached. | ||||||
Table 3. Electricity Use of
Non-seasonal Respondents |
||||||||
Total |
Attached |
Detached |
Total |
|||||
All-electric Households |
All-electric Households |
All-electric Households |
Natural Gas (1) Households |
|||||
Respondents |
% |
Respondents |
% |
Respondents |
% |
Respondents |
% |
|
| Annual Electricity Use |
||||||||
| <3000 kWh | 0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
| 3000-5999 kWh | 23 |
13.5 |
22 |
27.2 |
1 |
1.1 |
0 |
0 |
| 6000-8999 kWh | 28 |
16.5 |
28 |
34.6 |
0 |
0 |
9 |
8.7 |
| 9000-11999 kWh | 27 |
15.9 |
23 |
28.4 |
4 |
4.5 |
28 |
26.9 |
| 12000-14999 kWh | 15 |
8.8 |
7 |
8.6 |
8 |
9.0 |
24 |
23.1 |
| 15000-17999 kWh | 9 |
5.3 |
1 |
1.2 |
8 |
9.0 |
18 |
17.3 |
| 18000-20999 kWh | 16 |
9.4 |
0 |
0 |
16 |
18.0 |
15 |
14.4 |
| 21000-23999 kWh | 12 |
7.1 |
0 |
0 |
12 |
13.5 |
4 |
3.8 |
| 24000-26999 kWh | 11 |
6.5 |
0 |
0 |
11 |
12.4 |
3 |
2.9 |
| 27000-29999 kWh | 8 |
4.7 |
0 |
0 |
8 |
9.0 |
0 |
0 |
| >30000 kWh | 21 |
12.4 |
0 |
0 |
21 |
23.6 |
3 |
2.9 |
| Total Respondents | 170 |
81 |
89 |
104 |
||||
| Average annual kWh | 16,548 |
8,211 |
24,136 |
14,715 |
||||
| kWh/month | 1379 |
684 |
2000 |
1226 |
||||
| kWh/occupant/month | 568 |
458 |
668 |
559 |
||||
| kWh/ft2/month | 0.726 |
0.701 |
0.744 |
0.567 |
||||
| kWh/ft2/occupant/month | 0.349 |
0.482 |
0.253 |
0.260 |
||||
|
||||||||
Table 4. Distribution of Answers
to Energy Use Questions |
||||||
Total |
Attached |
Detached |
||||
Respondents |
% |
Respondents |
% |
Respondents |
% |
|
| Energy source | ||||||
| All electricity | 235 |
61.8 |
124 |
97.6 |
111 |
43.9 |
| Electricity & LP or natural gas |
145 |
38.2 |
3 |
2.4 |
142 |
56.1 |
| Heating source | ||||||
| Gas | 133 |
35.4 |
2 |
1.6 |
131 |
51.8 |
| Electricity | 243 |
64.6 |
121 |
98.4 |
122 |
48.2 |
| Electricity Heat Type | ||||||
| Forced air electric resistance heat |
101 |
45.9 |
69 |
68.3 |
32 |
26.9 |
| Heat pump | 119 |
54.1 |
32 |
31.7 |
87 |
73.1 |
| Heating temperature | ||||||
| <70 | 96 |
25.8 |
24 |
19.7 |
72 |
28.7 |
| 70-72 | 167 |
44.8 |
52 |
42.6 |
115 |
45.8 |
| 73-75 | 64 |
17.2 |
26 |
21.3 |
38 |
15.1 |
| >75 | 46 |
12.3 |
20 |
16.4 |
26 |
10.4 |
| Average reported set point | 71.43 |
71.95 |
71.18 |
|||
| Air conditioning (which months) |
||||||
| January | 28 |
7.4 |
13 |
10.3 |
15 |
5.9 |
| February | 36 |
9.5 |
17 |
13.5 |
19 |
7.5 |
March |
73 |
19.3 |
35 |
27.8 |
38 |
15.0 |
| April | 157 |
41.4 |
56 |
44.4 |
101 |
39.9 |
| May | 280 |
73.9 |
93 |
73.8 |
187 |
73.9 |
| June | 352 |
92.9 |
109 |
86.5 |
243 |
96.0 |
| July | 369 |
97.4 |
119 |
94.4 |
250 |
98.8 |
| August | 371 |
97.9 |
121 |
96.0 |
250 |
98.8 |
| September | 365 |
96.3 |
120 |
95.2 |
245 |
96.8 |
| October | 243 |
64.1 |
72 |
57.1 |
171 |
67.6 |
| November | 68 |
17.9 |
27 |
21.4 |
41 |
16.2 |
| December | 32 |
8.4 |
16 |
12.7 |
16 |
6.3 |
| Average number of months | 6.22 |
6.27 |
6.19 |
|||
| Natural ventilation (which months) |
||||||
| January | 266 |
77.1 |
94 |
79.7 |
172 |
75.8 |
| February | 268 |
77.1 |
93 |
78.8 |
175 |
77.1 |
| March | 273 |
79.1 |
87 |
73.7 |
186 |
81.9 |
| April | 226 |
65.5 |
70 |
59.3 |
156 |
68.7 |
| May | 122 |
35.4 |
44 |
37.3 |
78 |
34.4 |
| June | 45 |
13.0 |
22 |
18.6 |
23 |
10.1 |
| July | 28 |
8.1 |
14 |
11.9 |
14 |
6.2 |
| August | 26 |
7.5 |
12 |
10.2 |
14 |
6.2 |
| September | 45 |
13.0 |
22 |
18.6 |
23 |
10.1 |
| October | 192 |
55.7 |
72 |
61.0 |
120 |
52.9 |
| November | 301 |
87.2 |
99 |
83.9 |
202 |
89.0 |
| December | 277 |
80.3 |
92 |
78.0 |
185 |
81.5 |
| Average number of months | 5.44 |
5.68 |
5.32 |
|||
| Preventive factors | ||||||
| No adequate breeze | 57 |
15.4 |
32 |
26.0 |
25 |
10.1 |
| Lack of security | 39 |
10.5 |
10 |
8.1 |
29 |
11.7 |
| Too hot/cold/humid | 234 |
63.2 |
68 |
55.3 |
166 |
67.2 |
| Windows hard to operate/ inoperable |
2 |
0.5 |
0 |
0 |
2 |
0.8 |
| Excessive noise from traffic | 5 |
1.4 |
5 |
4.1 |
0 |
0 |
| Allergies | 32 |
8.6 |
8 |
6.5 |
24 |
9.7 |
| Other (dog barking) | 1 |
0.3 |
0 |
0 |
1 |
0.4 |
| Cooling temperature (F) | ||||||
| <75 | 43 |
11.4 |
20 |
16.0 |
23 |
9.1 |
| 75-77 | 75 |
19.9 |
24 |
19.2 |
51 |
20.2 |
| 78-80 | 237 |
62.8 |
74 |
59.3 |
163 |
64.7 |
| >80 | 22 |
5.8 |
7 |
5.6 |
15 |
6.0 |
| Average reported set point | 77.70 |
77.47 |
77.80 |
|||
| Set back behavior | ||||||
| Turn off air conditioner/heating | 58 |
15.2 |
32 |
25.2 |
26 |
10.2 |
| Thermostat to higher setting | 168 |
44.1 |
68 |
53.5 |
100 |
39.4 |
| Don't change the setting | 155 |
40.7 |
27 |
21.3 |
128 |
50.4 |
| Set back | ||||||
| Automatically | 14 |
8.3 |
6 |
8.8 |
8 |
7.9 |
| Manually | 155 |
91.7 |
62 |
91.2 |
93 |
92.1 |
| Ceiling & portable fans | ||||||
| None | 18 |
4.8 |
13 |
10.7 |
5 |
2.0 |
| One | 23 |
6.1 |
21 |
17.4 |
2 |
0.8 |
| Two | 49 |
13.0 |
33 |
27.3 |
16 |
6.3 |
| Three | 37 |
9.8 |
24 |
19.8 |
13 |
5.1 |
| Four | 62 |
16.5 |
20 |
16.5 |
42 |
16.5 |
| Five | 61 |
16.2 |
4 |
3.3 |
57 |
22.4 |
| Six | 60 |
16.0 |
3 |
2.5 |
57 |
22.4 |
| Seven or more | 66 |
17.6 |
3 |
2.5 |
63 |
24.7 |
| Average number of fans | 4.46 |
2.50 |
5.39 |
|||
| Fan usage to reduce a/c use |
||||||
| Always | 196 |
52.3 |
60 |
48.8 |
136 |
54.0 |
| Frequently | 122 |
32.5 |
33 |
26.8 |
89 |
35.3 |
| Occasionally | 34 |
9.1 |
13 |
10.6 |
21 |
8.3 |
| Never | 23 |
6.1 |
17 |
13.8 |
6 |
2.4 |
| Use fans with air conditioner |
||||||
| Yes | 333 |
89.8 |
97 |
80.2 |
236 |
94.4 |
| No | 38 |
10.2 |
24 |
19.8 |
14 |
5.6 |
| Water heater | ||||||
| Electric | 216 |
57.9 |
115 |
96.6 |
101 |
39.8 |
| Air conditioner heat exchanger | 14 |
3.8 |
2 |
1.7 |
12 |
4.7 |
| Gas | 138 |
37.0 |
2 |
1.7 |
136 |
53.5 |
| Heat pump | 5 |
1.3 |
0 |
0 |
5 |
2.0 |
| More than one refrigerator |
||||||
| Yes | 73 |
19.1 |
5 |
3.9 |
68 |
26.7 |
| No | 309 |
80.9 |
122 |
96.1 |
187 |
73.3 |
| Seperate freezer | ||||||
| Yes | 86 |
22.6 |
13 |
10.2 |
73 |
28.7 |
| No | 295 |
77.4 |
114 |
89.8 |
181 |
71.3 |
| Clothes washer | ||||||
| Inside the house | 347 |
90.8 |
115 |
90.6 |
232 |
91.0 |
| In the garage/porch | 24 |
6.3 |
3 |
2.4 |
21 |
8.2 |
| No clothes washer | 11 |
2.9 |
9 |
7.1 |
2 |
0.8 |
| Loads per week (average) | 5.04 |
4.01 |
5.54 |
|||
| Clothes dryer | ||||||
| Electric | 290 |
75.5 |
116 |
90.6 |
174 |
68.0 |
| Gas | 82 |
21.4 |
3 |
2.3 |
79 |
30.9 |
| No dryer | 12 |
3.1 |
9 |
7.0 |
3 |
1.2 |
| Do you use a clothesline | ||||||
| Always | 7 |
1.8 |
1 |
0.8 |
6 |
2.4 |
| Frequently | 18 |
4.7 |
7 |
5.5 |
11 |
4.3 |
| Occasionally | 44 |
11.5 |
7 |
5.5 |
37 |
14.6 |
| Never | 312 |
81.9 |
112 |
88.2 |
200 |
78.7 |
| Do you use a dish water | ||||||
| Always | 190 |
49.5 |
44 |
34.4 |
146 |
57.0 |
| Frequently | 85 |
22.1 |
21 |
16.4 |
64 |
25.0 |
| Occasionally | 88 |
22.9 |
48 |
37.5 |
40 |
15.6 |
| Never | 21 |
5.5 |
15 |
11.7 |
6 |
2.3 |
| Heated water beds | ||||||
| None | 337 |
90.1 |
111 |
88.1 |
226 |
91.1 |
| One | 30 |
8.0 |
12 |
9.5 |
18 |
7.3 |
| Two or more | 7 |
1.9 |
3 |
2.4 |
4 |
1.6 |
| Do trees help shade your house |
||||||
| Almost totally | 11 |
2.9 |
3 |
2.4 |
8 |
3.1 |
| Partially | 153 |
40.1 |
52 |
40.9 |
101 |
39.3 |
| None | 218 |
57.1 |
72 |
56.7 |
146 |
57.3 |
Natural gas homes
One hundred forty-nine homes had natural gas. One hundred forty-five (97%) of these homes were detached. The natural gas homes averaged 2,179 square feet. As illustrated in Figure 13, the annual electricity use per square foot of floor area in the homes with gas is 23% less. Figure 14 shows the month by month relationship. During the winter peak, electricity use in the gas homes was just 47% the electricity use in the all electric homes on a per square foot basis. This indicates that about half of the electricity consumption in the all-electric group of houses or 840 kWh, was associated with monthly space or water heating. The summer peak represented a mere 4% difference.
7.0 Transportation Energy Use
The transportation analysis results are more subject to error since they are based on the respondents' estimates as to miles each car they owned was driven in the past year rather than on actual odometer readings. Distances and frequencies of trips were likely roughly estimated by most respondents.
Table 6 presents responses to the questions regarding convenience and safety of walking and bicycle use. Highlights are:
- A considerable majority of the respondents in the attached developments thought it was easy to get around without a car inside the development and to access recreational facilities. About 50% of the detached households answered similarly.
- Food stores were easily accessible by walking or bicycling according to 42% of attached households as compared to only 4% of detached households.
- Each group answered overwhelmingly (95%) that it was safe to ride a bicycle in the development. However, 57% of the attached households thought it was also safe outside the development compared to only 16% of the detached households.
- In responding to the question if anyone in the household rides a bicycle or walks to the store or a recreational area such as a beach or a park on a regular basis, 47% of attached households indicated they did, compared to only 17% of the detached households. In households with non-drivers, 30% of the respondents said they walked or biked regularly, with 64% of the attached households and only 25% of the detached households answering to the affirmative. This may be a more reliable indicator as to the true convenience of these facilities.
Table 5. Distribution of Answers
to Pool/Spa Use Questions |
||||||
Total |
Attached |
Detached |
||||
Respondents |
% |
Respondents |
% |
Respondents |
% |
|
| Do you own spa/pool | ||||||
| Pool only | 115 |
31.6 |
2 |
1.8 |
113 |
45.2 |
| Spa only | 10 |
2.7 |
3 |
2.6 |
7 |
2.8 |
| Both | 34 |
9.3 |
1 |
0.9 |
33 |
13.2 |
| Neither | 205 |
56.3 |
108 |
94.7 |
97 |
38.8 |
| Spa/pool heat | ||||||
| Electric heat pump | 16 |
10.4 |
3 |
75.0 |
13 |
8.7 |
| Gas/propane | 40 |
26.0 |
0 |
0 |
40 |
26.7 |
| Solar | 19 |
12.3 |
0 |
0 |
19 |
12.7 |
| None | 79 |
51.3 |
1 |
25.0 |
78 |
52.0 |
| Spa/pool cover | ||||||
| Yes | 44 |
28.4 |
3 |
50.0 |
41 |
27.5 |
| No | 111 |
71.6 |
3 |
50.0 |
108 |
72.5 |
| Spa/pool pump hours per day |
||||||
| 3 or less | 15 |
9.8 |
1 |
33.3 |
14 |
9.3 |
| 4 to 6 | 52 |
34.0 |
2 |
66.7 |
50 |
33.3 |
| 7 to 9 | 64 |
41.8</ | ||||