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:

Other highlights of the differences between households include:
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:
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 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:
Additionally, new land developments should:
Questions raised by the analysis include:
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.
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:
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 |
0 |
0 |
64 |
42.6 |
| 10 or more | 22 |
14.4 |
0 |
0 |
22 |
14.7 |
| Average | 7.67 |
4.00 |
7.74 |
|||


Table 6. Transportation Perception
and Activities |
||||
Total |
Attached |
Detached |
||
# |
% |
|||
| Is it easy to get around without a car |
||||
| Yes | 251 |
66 |
89 % |
54 % |
| No | 132 |
34 |
11 % |
46 % |
| Recreational facilities | ||||
| Easily accessible | 208 |
55 |
66 % |
49 % |
| Car necessary | 173 |
45 |
34 % |
51 % |
| Stores accessible on foot/bicycle | ||||
| Easily accessible | 64 |
17 |
42 % |
4 % |
| Car necessary | 319 |
83 |
58 % |
96 % |
| Is it safe to ride a bicycle in your development |
||||
| Yes | 363 |
95 |
95 % |
95 % |
| No | 19 |
5 |
5 % |
5 % |
| Outside your development | ||||
| Yes | 112 |
30 |
57 % |
16 % |
| No | 262 |
70 |
43 % |
84 % |
| Does anyone in your household ride a bicycle or walk to store or a recreational area (all households) | ||||
| Yes | 102 |
27 |
47 % |
17 % |
| No | 280 |
73 |
53 % |
83 % |
| Does anyone in your household ride a bicycle or walk to store or a recreational area (households with non-drivers) |
||||
| Yes | 25 |
30.1 |
63.6 % |
25.0 % |
| No | 58 |
69.9 |
36.4 % |
75.0 % |
Table 9 presents characteristics of the households that relate to transportation use and the miles driven. The average total household distance driven for attached dwellings was 15,615 miles, against 23,121 miles per year for the detached units as illustrated in Figure 15. On a per driver basis it was 11,028 miles for attached dwellings and 10,636 miles for detached group (Figure 16). On the basis of automobiles, the total distance driven represented 11,409 miles per car for the attached group and 11,763 miles for the detached households. Thus, on a per driver or per automobile basis the reported mileage was almost equal between attached and detached households.
On a per occupant basis Table 7 shows attached households as driving 10,621 miles per occupant compared to only 9133 for detached households as shown in Figure 17. Because the mileage per driver is almost equal this indicates that there are more non-drivers (young children) in the detached households. A more accurate depiction of driving mileage per occupant is shown in Figure 18. For the same occupancy level, attached households have the same or fewer average miles than detached households, but the differences are not large. Figure 19 demonstrates that as household size increases, miles per occupant decreases, resulting in a lower overall mileage per occupant for the detached households (demographic data on occupants is shown in Table 1).
By comparison, in 1988 the U.S. average household drove 18,595 miles, owned 1.8 vehicles, for 10,246 miles driven per motor vehicle. Per vehicle fuel consumption was 559 gallons and per household vehicle fuel consumption was 1014 gallons with an overall on-road vehicle miles-per-gallon of 18.3. Average occupancy exceeded 2.85 persons per household. These results are based on a national survey with respondents recording odometer readings throughout the year.
Table 8 shows average trip length, frequency of trips and miles per month per household for selected errand-type trips. Trips to shopping malls were made an average of 3.72 times per month, and represented the longest average distance, 10.75 miles. College, home improvement centers, and theater trips were all over eight miles on average, but individually do not represent the miles per month per average household as shopping malls or grocery stores.
Attached households reported average trip lengths that were closer to every listed designation except for recreational/golf trips. The detached households were pre-selected as being part of golf course developments, so this exception is well understood, although all of the attached households have a recreational facility as well. In Table 8, it should be noted that respondents were asked to list the distance and frequency of trips to the designation they visited the most. In many situations a respondent may regularly visit a grocery store twice the distance from home to another grocery store because they perceive better value at that store. Respondents' errand mileage (the sum of all these individual trips) averaged to 474 miles per household per month. Detached households had about twice the errand trip mileage of attached households.
Table 7. Mileage and Household
Transportation Characteristics |
|||||||
Total Respondents |
Attached |
Detached |
|||||
| Annual Household Mileage | Average # of cars per household |
Resp. |
% |
Resp. |
% |
Resp. |
% |
| <3,000 | 1.125 |
8 |
2.3 |
7 |
6.2 |
1 |
0.4 |
| 3,000-6,000 | 1.143 |
14 |
4.0 |
11 |
9.7 |
3 |
1.3 |
| 6,001-9,000 | 1.280 |
25 |
7.1 |
10 |
8.8 |
15 |
6.3 |
| 9,001-12,000 | 1.231 |
52 |
14.7 |
23 |
20.4 |
29 |
12.1 |
| 12,001-15,000 | 1.587 |
46 |
13.0 |
16 |
14.2 |
30 |
12.5 |
| 15,001-18,000 | 1.870 |
23 |
6.5 |
4 |
3.5 |
19 |
7.9 |
| 18,001-21,000 | 1.846 |
39 |
11.0 |
16 |
14.2 |
23 |
9.6 |
| 21,001-24,000 | 2.053 |
38 |
10.8 |
7 |
6.2 |
31 |
12.9 |
| 24,001-27,000 | 2.174 |
23 |
6.5 |
6 |
5.3 |
17 |
7.1 |
| 27,001-30,000 | 2.095 |
21 |
5.9 |
5 |
4.4 |
16 |
6.7 |
| 30,001-33,000 | 2.182 |
11 |
3.1 |
3 |
2.7 |
8 |
3.3 |
| 33,001-36,000 | 2.500 |
14 |
4.0 |
1 |
0.9 |
13 |
5.4 |
| 36,001-39,000 | 2.375 |
8 |
2.3 |
0 |
0 |
8 |
3.3 |
| 39,001-42,000 | 2.286 |
14 |
4.0 |
2 |
1.8 |
12 |
5.0 |
| 42,001-45,000 | 2.500 |
4 |
1.1 |
0 |
0 |
4 |
1.7 |
| 45,001-48,000 | 4.000 |
1 |
0.3 |
0 |
0 |
1 |
0.4 |
| 48,001-51,000 | 2.875 |
8 |
2.3 |
1 |
0.9 |
7 |
2.9 |
| >51,000 | 3.667 |
3 |
0.8 |
0 |
0 |
3 |
1.3 |
| Total Respondents | 353 |
113 |
240 |
||||
Total Respondents |
Attached |
Detached |
|||||
| Average annual miles driven | 20,718 |
15,615 |
23,121 |
||||
| Miles per occupant | 9,605 |
10,621 |
9,133 |
||||
| Miles per driver | 10,761 |
11,028 |
10,636 |
||||
| Miles per automobile | 11,650 |
11,409 |
11,763 |
||||
| Number of automobiles per household | 1.81 |
1.389 |
2.01 |
||||
| Number of workers per household | 1.00 |
0.95 |
1.02 |
||||
| Number of drivers* per household | 1.98 |
1.51 |
2.21 |
||||
| School per household | 0.37 |
0.08 |
0.52 |
||||
| Average length of trip to school (miles) | 6.85 |
4.60 |
7.02 |
||||
| *Drivers were assumed to be anyone age 16 or older except for occupants of households that listed zero as car mileage (three elderly households). Any non-drivers age 16 or older that live with drivers are erronously counted as drivers. | |||||||





Table 8. Errand Trips |
||||
Total Respodents |
||||
Resp. |
Trip Length (Miles) |
Frequency (Trips/Month) |
Miles per House per Month |
|
| Grocery Store | 375 |
5.57 |
8.64 |
93.99 |
| Drug Store | 355 |
5.64 |
3.18 |
33.16 |
| Convenience Store | 327 |
2.02 |
6.59 |
22.67 |
| College | 131 |
9.20 |
6.52 |
40.93 |
| Restaurant | 316 |
7.06 |
5.20 |
60.42 |
| Shopping Mall | 354 |
10.75 |
3.72 |
73.73 |
| Place of Worship | 269 |
6.05 |
4.89 |
57.53 |
| Recreation/Golf | 258 |
4.78 |
8.59 |
55.17 |
| Movies/Theater | 285 |
8.13 |
2.01 |
24.26 |
| Laundromat | 73 |
3.45 |
0.78 |
1.02 |
| Home Improvement Center | 246 |
8.99 |
2.36 |
27.18 |
| Average trip length | 6.05 miles |
|||
| Average miles per month | 474 |
|||
Attached |
||||
Resp. |
Trip Length (Miles) |
Frequency (Trips/Month) |
Miles per House per Month |
|
| Grocery Store | 125 |
3.22 |
6.95 |
43.71 |
| Drug Store | 115 |
3.23 |
2.84 |
16.48 |
| Convenience Store | 107 |
1.42 |
6.13 |
14.55 |
| College | 45 |
6.20 |
6.71 |
29.25 |
| Restaurant | 102 |
4.98 |
5.02 |
39.84 |
| Shopping Mall | 114 |
7.69 |
3.37 |
46.16 |
| Place of Worship | 75 |
4.40 |
4.35 |
22.43 |
| Recreation/Golf | 71 |
5.63 |
6.55 |
40.91 |
| Movies/Theater | 94 |
6.19 |
2.09 |
19.00 |
| Laundromat | 31 |
1.48 |
1.00 |
0.71 |
| Home Improvement Center | 63 |
5.73 |
2.82 |
15.91 |
| Average trip length | 4.36 miles |
|||
| Average miles per month | 289 |
|||
Detached |
||||
Resp. |
Trip Length (Miles) |
Frequency (Trips/Month) |
Miles per House per Month |
|
| Grocery Store | 250 |
6.75 |
9.46 |
124.72 |
| Drug Store | 24 |
6.80 |
3.34 |
42.58 |
| Convenience Store | 220 |
2.30 |
6.80 |
26.88 |
| College | 86 |
10.77 |
6.44 |
46.60 |
| Restaurant | 214 |
8.06 |
5.28 |
71.15 |
| Shopping Mall | 240 |
12.20 |
3.89 |
88.98 |
| Place of Worship | 194 |
6.69 |
5.09 |
51.61 |
| Recreation/Golf | 187 |
4.45 |
9.34 |
60.72 |
| Movies/Theater | 191 |
9.08 |
1.97 |
26.69 |
| Laundromat | 42 |
4.90 |
0.66 |
1.06 |
| Home Improvement Center | 183 |
10.11 |
2.21 |
31.94 |
| Average trip length | 6.78 miles |
|||
| Average miles per month | 573 |
|||
Table 9 presents reported work trip characteristics. Distance to work has been grouped although respondents answers were given numerically. On average there is one worker per household, although some households had four workers and many had none. The average length of a trip to work was 16 miles. Only 3.1% lived within one mile of work, possibly the longest distance one would regularly walk. Almost one in four workers lives within five miles of work, possibly the maximum bicycling distance for most people. 37.2% of attached household workers lived within five miles of work whereas only 18.5% of detached household workers lived that close. The average length of a trip to work was 13.9 miles for workers in attached households and 16.9 miles for workers in detached households. Attached household workers went to work 6.0 times per week on average compared to only 5.7 times for detached household workers. Average miles traveled to work and back each week was 8.6% greater for a worker living in a detached household.
Not surprisingly, transport mode choice for work trips was overwhelmingly dominated by use of personal automobiles. Three workers' primary mode was by bicycle, five by walking, and one by bus. Fifteen workers claimed they car-pooled (not one of the provided questionnaire choices). Three hundred sixty-nine of the 386 workers responded that they usually drove to work (some car-poolers may have said both). This represents 95.6% of the workers. Only 2.3% did not use private motor vehicles for their primary mode (4 attached household workers, 5 detached household workers).
Table 10 shows mode choice, mileage and school types for the 139 school children that responded. This data is not divided by attached and detached because only ten school children live in the attached households. None of the school children walk to school as their typical mode choice. One child (from a detached household) bicycles to school. One in three school children take the bus and 66.2% drive or are driven. One respondent wrote that a child is car-pooled (not a provided choice).
Only 25 of the 89 elementary, middle and high school children live within two miles of the school they attend (typical maximum school bicycling distance). However, only one of those school children bicycled. Average mileage is 4.7 to elementary school, 8.2 to middle school and 8.2 to high school. Average mileage to preschool is 7.2 miles, for an overall average of 6.9 miles. Those school trips that are driven are 8.3 miles on average. As with errand trips, school trips may be part of the trip to or back from work for some drivers. Questions regarding combining trips were not posed, nor were questions regarding school type (i.e., private or public).
Table 9. Work Trips |
|||||||||
Total |
Attached |
Detached |
|||||||
Workers |
% |
Frequency |
Workers |
% |
Frequency |
Workers |
% |
Frequency |
|
| Work Distance (miles) |
|||||||||
| 0-1 | 12 |
3.1 |
6.18 |
6 |
5.0 |
6.83 |
6 |
2.3 |
5.40 |
| 2 | 22 |
5.7 |
6.09 |
10 |
10.7 |
6.20 |
12 |
4.5 |
6.00 |
| 3-5 | 57 |
14.8 |
6.05 |
26 |
21.5 |
5.50 |
31 |
11.7 |
6.53 |
| 6-10 | 86 |
22.3 |
5.85 |
29 |
24.0 |
6.60 |
57 |
21.5 |
5.42 |
| 11-15 | 85 |
22.0 |
5.21 |
18 |
14.9 |
5.44 |
67 |
25.3 |
5.24 |
| 16-20 | 36 |
9.3 |
5.20 |
6 |
5.0 |
5.00 |
30 |
11.3 |
5.24 |
| 21-25 | 23 |
6.0 |
5.22 |
8 |
6.6 |
6.63 |
15 |
5.7 |
4.47 |
| 26-30 | 13 |
3.4 |
5.42 |
6 |
5.0 |
5.00 |
7 |
2.6 |
5.71 |
| >30 | 52 |
13.5 |
6.75 |
12 |
9.9 |
6.75 |
40 |
15.1 |
5.65 |
| Total |
386 |
121 |
265 |
||||||
| Average |
15.95 miles |
5.79 |
13.92 miles
|
6.00 |
16.88 miles |
5.69 |
|||
| Weekly average miles |
178.2 |
167.4 |
183.2 |
||||||
| Weekly average miles if driving | 183.1
|
171.0
|
188.8 |
||||||
Table 10. School Trips |
||||||
School Children |
Bus % |
Bicycles % |
Driven % |
Walks % |
Other % |
|
| Miles to School | ||||||
| Preschool | ||||||
| 0-1 | 2 |
0 % |
0 % |
100 % |
0 % |
0 % |
| 2 | 9 |
0 % |
0 % |
100 % |
0 % |
0 % |
| 3-5 | 11 |
0 % |
0 % |
100 % |
0 % |
0 % |
| 6-10 | 17 |
0 % |
0 % |
100 % |
0 % |
0 % |
| >10 | 11 |
0 % |
0 % |
100 % |
0 % |
0 % |
| Average = 7.16 | ||||||
| Elementary | ||||||
| 0-1 | 6 |
67 % |
0 % |
33 % |
0 % |
0 % |
| 2 | 9 |
67 % |
0 % |
33 % |
0 % |
0 % |
| 3-5 | 12 |
67 % |
0 % |
33 % |
0 % |
0 % |
| 6-10 | 8 |
50 % |
0 % |
50 % |
0 % |
0 % |
| >10 | 4 |
0 % |
0 % |
100 % |
0 % |
0 % |
| Average = 4.74 | ||||||
| Middle | ||||||
| 0-1 | 1 |
0 % |
100 % |
0 % |
0 % |
0 % |
| 2 | 2 |
0 % |
0 % |
100 % |
0 % |
0 % |
| 3-5 | 8 |
100 % |
0 % |
0 % |
0 % |
0 % |
| 6-10 | 6 |
100 % |
0 % |
0 % |
0 % |
0 % |
| >10 | 4 |
0 % |
0 % |
100 % |
0 % |
0 % |
| Average = 8.19 | ||||||
| High | ||||||
| 0-1 | 1 |
0 % |
0 % |
100 % |
0 % |
0 % |
| 2 | 6 |
33 % |
0 % |
50 % |
0 % |
17 %* |
| 3-5 | 13 |
54 % |
0 % |
46 % |
0 % |
0 % |
| 6-10 | 1 |
0 % |
0 % |
100 % |
0 % |
0 % |
| >10 | 8 |
0 % |
0 % |
100 % |
0 % |
0 % |
| Average = 8.17 | ||||||
| Total | 100.0 % |
32.3 % |
0.7 % |
66.2 % |
0 % |
0.7 % |
| Total School Children | 139 |
45 |
1 |
92 |
0 |
1 |
| Average Mileage | 6.85 |
4.22 |
2.00 |
8.28 |
--- |
2.00 |
|
||||||




Figure 20 shows the relationship of average trip lengths for work, errands and school for attached and detached households. In each case, the average trip length was shorter for the attached households. Figure 21 shows the monthly miles contributed by work, errand and school trips for attached and detached households. The detached dwelling occupants drive consistently more miles to school, work and errands each month. Figure 22 shows the proportional relationship of these trips to the overall reported average mileage for attached household residents. Note that about 28% of the mileage is unaccounted for by the questionnaire. Figure 23 shows the same information for the detached households, with 24% remaining undetermined by the questionnaire. There are many trips which respondents may have taken but were not asked to report. In addition to little errands, there could be music lessons for children, weekend and night trips to school, trips to friends and relatives that live locally, trips to artistic or sports events and longer vacation or business trips. In regard to energy use, long distance trips may include air and rail modes. Since air travel is significantly less efficient than driving (particularly if there is more than one person in the automobile), those that travel by air would use more fuel despite having fewer motor vehicle miles.
Actual fuel use was not collected. Makes and models of automobiles were collected and the relationship between distance travelled and estimated fuel consumption of vehicle can be explored by using Environmental Protection Agency miles per gallon figures. However that represents effort is reserved for the future as it does not represent a strong impact on the detached versus attached dwelling development patterns. For all vehicles on Florida's roads in 1990, gasoline mileage may be approximated as 20 miles per gallon.
8.0 Combined Transportation and Electricity Use
In order to estimate differences in total annual energy used for transportation and electricity, certain simplifying assumptions were made:
The resulting conversions into million Btus of energy are:
10_6Btu_e = kWh * 0.003413/0.305
10_6Btu_t = miles * 0.125/20
For readers more comfortable with metric units, one million Btu's are equal to 1,055 MJ. Only non-seasonal, all-electric households are used for this analysis.
There were 75 attached households and 83 detached households that were non-seasonal, all-electric respondents having answered total mileage questions, and having all year electricity data. Figure 24 illustrates the estimated energy use for each component by household type. Attached households use an average of 177 million Btus total, with 88 million Btus for transportation and 89 million Btus for electricity. By our estimates detached household respondents used 2.4 times as much total energy as attached households. The detached households use an average of 432 million Btus, with 164 million Btus being used for transportation and 268 Btus being used for electricity. The average respondent (of the 158 attached and detached respondents) used 311 million Btus total, 128 million Btus for transportation, and 183 million Btus for electricity.
Electricity and transportation energy use was about equal for the attached households, but electricity use was 63% larger than transportation energy use for the detached households. Over all respondents, the electricity energy use was 43% higher than for transportation.


Figure 25 illustrates total estimated energy use by household size for the attached and detached households. It clearly shows that:
1) as occupancy increases household energy use increases
2) the ratio of energy use to occupants decreases with increasing occupancy
3) detached households consumed 150 to 220 million Btus more than attached households of equal occupancy. This represents 85% to 99% greater energy use.
Because there are more occupants per household in the detached households there is not as much difference on an overall energy-use-per-occupant basis between the two building types. Detached households averaged 145 million Btus per occupant and attached households averaged 120 million Btus per occupant. Thus, energy use per occupant was 20% higher for detached households. In households of equal size, detached households used 21% (4-person) to 99% (1-person) more energy per occupant than attached households. However, only five attached households of more than two occupants are included in the comparison sample. The overall average value was 133 million Btus per occupant.
By way of comparison, in 1988 total per capita energy consumption in Florida was 239 million Btus. Per capita electricity consumption was 116 million Btus. These values include non-residential energy use as well. Residential building energy use is 25.8% of total Florida energy use, and total transportation energy use is 35.8%. Seventy-one percent of transportation energy use is for motor gasoline. Some of this motor gasoline is for commercial uses. If we assume 50% of Florida's transportation energy use is by household vehicles, then 43.7% of the 239 million Btus per person, or 104 million Btus per person should be used as a comparison number to the data in the previous paragraph.
Nationally, 44.5 MBtu's per person are used for household vehicle fuel. Households that are air-conditioned and heated by electricity use 52.5 MBtu's of electricity. Converting this into raw fuel used at the power plant equates to 169.4 MBtu per household or approximately 65 MBtu/person. Therefore, nationally, about 110 MBtu's are consumed per occupant for household electricity and vehicle fuel.
9.0 Water and Landscape Responses
Full analysis of water and landscape responses will be left for a future report. Because water use for most of the attached dwellings is group billed it is difficult to characterize water use to respondents in those categories. Only a few attached households have private yards or gardens.
Table 11 shows the responses to interior water use questions. Although the number of baths (includes showers) per week was significantly higher for the detached households it proved to be slightly smaller on a per occupant basis than attached households. 23% of the attached households had an occasional or more frequently, leaky faucet or running toilet compared to just 8% of the detached households (this may relate to the attached households not being billed directly for water use or unresponsiveness of landlords to such problems).
Table 12 shows the tally of respondents answers to landscaping questions. Highlights of the responses include:
10.0 Applying Results to New Land Development Design
Certain recommendations can be made directly from the questionnaire results. An energy-efficient development should:
Table 11. Distribution of Answers
on Interior Water Use |
||||||
Total |
Attached |
Detached |
||||
Respondents |
% |
Respondents |
% |
Respondents |
% |
|
| Low-flow showerheads | ||||||
| Yes | 219 |
59.0 |
68 |
55.3 |
151 |
60.9 |
| No | 152 |
41.0 |
55 |
44.7 |
97 |
39.1 |
| Drippy faucet or running toilet |
||||||
| Always | 1 |
0.3 |
0 |
0 |
1 |
0.4 |
| Frequently | 3 |
0.8 |
1 |
0.8 |
2 |
0.8 |
| Occasionally | 47 |
12.3 |
29 |
22.7 |
18 |
7.1 |
| Never | 332 |
86.7 |
98 |
76.6 |
234 |
91.8 |
| Number of baths | ||||||
| Per household per week average |
16.21 |
11.92 |
18.35 |
|||
| Per occupant per week average |
7.20 |
7.61 |
7.00 |
|||
Table 12. Distribution of Answers
on Landscaping and Exterior Water Use |
||||||
Total |
Attached |
Detached |
||||
Respondents |
% |
Respondents |
% |
Respondents |
% |
|
| Native landscape | ||||||
| 0 to 10 % | 230 |
66.7 |
53 |
51.0 |
177 |
73.4 |
| 10 % to 25 % | 50 |
14.5 |
17 |
16.3 |
33 |
13.7 |
| 25 % to 50 % | 32 |
9.3 |
14 |
13.5 |
18 |
7.5 |
| Over 50 % | 33 |
9.6 |
20 |
19.2 |
13 |
5.4 |
| Lot size | ||||||
| No lot | 16 |
5.9 |
15 |
62.5 |
1 |
0.4 |
| Under 1/4 acre | 81 |
29.7 |
8 |
33.3 |
73 |
29.3 |
| 1/4 to 1/2 acre | 137 |
50.2 |
1 |
4.2 |
136 |
54.6 |
| Over 1/2 acre | 39 |
14.3 |
0 |
0 |
39 |
15.7 |
| Average hours/week spent maintaining yard |
4.14
|
1.00
|
4.30
|
|||
| Those that use | ||||||
| Pest control chemicals | 223 |
58.1 |
10 |
7.8 |
213 |
83.2 |
| Chemical fertilizers | 221 |
57.6 |
9 |
7.0 |
212 |
82.8 |
| Weed control chemicals | 181 |
47.1 |
4 |
3.1 |
177 |
69.1 |
| No chemicals | 8 |
2.1 |
2 |
1.6 |
6 |
2.3 |
| Do you grow | ||||||
| Fruits | 36 |
13.5 |
2 |
10.5 |
34 |
13.8 |
| Vegetables | 8 |
3.0 |
0 |
0 |
8 |
3.2 |
| Both | 15 |
5.6 |
1 |
5.3 |
14 |
5.7 |
| Neither | 207 |
77.8 |
16 |
84.2 |
191 |
77.3 |
| Water source for yard/garden |
||||||
| City/municipality | 115 |
43.2 |
9 |
45.0 |
106 |
43.1 |
| Ground water well | 147 |
55.3 |
10 |
50.0 |
137 |
55.7 |
| Both | 4 |
1.5 |
1 |
5.0 |
3 |
1.2 |
| Times a month water average |
11.0
|
9.0
|
11.1
|
|||
| Type of water system | ||||||
| Automatic sprinklers | 257 |
95.9 |
14 |
77.8 |
243 |
97.2 |
| Manual sprinklers | 10 |
3.7 |
4 |
22.2 |
6 |
2.4 |
| Both | 1 |
0.4 |
0 |
0 |
1 |
0.4 |
| Use lawn for social / recreational activities | ||||||
| Yes | 32 |
11.8 |
1 |
4.8 |
31 |
12.4 |
| No | 240 |
88.2 |
20 |
95.2 |
220 |
87.6 |
From a marketing viewpoint many of the respondents answers, including these shown in Table 13 may suggest certain qualities that should be improved upon:
Many of these suggestions cannot be easily implemented within most Florida city and county regulations. Areas are zoned separately, not allowing commercial and residential areas nearby, and certainly not within walking distance. Areas are also zoned or deed rstricted based on a minimum square footage (often conditioned-square footage) of floor area of the homes. The state encourages large schools at the expense of having students travel further distances. More small schools would be desirable. Traffic corridors are planned and changed by state, regional, county and city groups. Rarely is the pedestrian or bicyclist given equal consideration.
Table 13. Community Preferences |
||||||
Total |
Attached |
Detached |
||||
Respondents |
% |
Respondents |
% |
Respondents |
% |
|
| Like most about development* | ||||||
| Clean, well maintained | 133 |
37.7 |
38 |
32.8 |
95 |
40.1 |
| Restrictive | 35 |
9.9 |
3 |
2.6 |
32 |
13.5 |
| Convenient location | 76 |
21.5 |
33 |
28.4 |
43 |
18.1 |
| Landscaping, views | 117 |
33.1 |
40 |
34.5 |
77 |
32.5 |
| Quiet, uncrowded | 109 |
30.9 |
30 |
25.9 |
79 |
33.3 |
| Safe, low crime | 67 |
19.0 |
29 |
25.0 |
38 |
16.0 |
| Facilities | 83 |
23.5 |
31 |
26.7 |
52 |
21.9 |
| Nice neighbors | 35 |
9.9 |
7 |
6 |
28 |
11.8 |
| Resale value | 9 |
2.5 |
0 |
0 |
9 |
3.8 |
| Others | 7 |
2.0 |
2 |
1.7 |
5 |
2.1 |
| Like least about development** | ||||||
| Not convenient | 63 |
25.5 |
8 |
9.6 |
55 |
33.5 |
| Poor maintained | 16 |
6.5 |
7 |
8.4 |
9 |
5.5 |
| No trees | 19 |
7.7 |
6 |
7.2 |
13 |
7.9 |
| Association needs power | 20 |
8.1 |
10 |
12.0 |
10 |
6.1 |
| Noise, crowd | 14 |
5.7 |
10 |
12.0 |
4 |
2.4 |
| Bad traffic, no lights | 32 |
13.0 |
10 |
12.0 |
22 |
13.4 |
| Size too small | 5 |
2.0 |
5 |
6.0 |
0 |
0 |
| Poor security | 14 |
5.7 |
6 |
7.2 |
8 |
4.9 |
| Over developed, new | 49 |
19.8 |
12 |
14.5 |
37 |
22.6 |
| High cost, high rent | 29 |
11.7 |
13 |
15.7 |
16 |
9.8 |
| Poorly constructed, other | 32 |
13.0 |
13 |
15.7 |
19 |
11.6 |
| Features you would like to see*** |
||||||
| Community swimming pool |
17 |
7.5 |
4 |
5.6 |
13 |
8.4 |
| Community entertainment/social bldg. | 27 |
11.9 |
9 |
12.5 |
18 |
11.7 |
| Church/Synagogue or other |
14 |
6.2 |
3 |
4.2 |
11 |
7.1 |
| Restaurant | 93 |
41.2 |
27 |
37.5 |
66 |
42.9 |
| Laundromat | 4 |
1.8 |
0 |
0 |
4 |
2.6 |
| Neighborhood park | 43 |
19.0 |
18 |
25.0 |
25 |
16.2 |
| More children | 24 |
10.6 |
3 |
4.2 |
21 |
13.6 |
| Fewer children | 9 |
4.0 |
5 |
6.9 |
4 |
2.6 |
| Golf course | 16 |
7.1 |
8 |
11.1 |
8 |
5.2 |
| Tennis courts | 15 |
6.6 |
3 |
4.2 |
12 |
7.8 |
| Grocery store | 122 |
54.0 |
25 |
34.7 |
97 |
63.0 |
| Others | 44 |
19.5 |
17 |
23.6 |
27 |
17.5 |
| Other features you would like (write-ins) |
||||||
| Wide streets | 6 |
1.6 |
4 |
3.1 |
2 |
0.8 |
| Shopping center | 24 |
6.3 |
5 |
3.9 |
19 |
7.4 |
| Parking lot | 1 |
0.3 |
1 |
0.8 |
0 |
0 |
| Fitness, playground | 7 |
1.8 |
3 |
2.3 |
4 |
1.6 |
| School, others | 13 |
3.4 |
5 |
3.9 |
8 |
3.1 |
* More than one response per
person, 353 respondents ** More than one response per person, 247 respondents *** More than one response per person, 226 respondents |
||||||
11.0 Implications for Respondents
The results indicate that respondents may not be fully aware of no-cost, energy saving methods available to them. The most significant of these are:
12.0 Conclusions
Surveyed detached households used significantly more electricity than attached households. Larger house size (square footage) and greater occupancy in the detached households accounts for most of the differences. The detached households used less electricity on a per square foot per occupant basis than attached households. However part of the result is from decreasing electricity use per square foot per person as occupancy increases. Comparing households with equal number of occupants showed that attached households use about equal amounts of electricity on the basis of floor area and occupancy.
Results indicate electricity use can be reduced by greater levels of occupancy for a given floor area -- exactly the opposite of current demographic trends. For example, less energy would typically be used by having 4 occupants in one household, than to have one household with 3 occupants and one household with one occupant. In terms of development patterns and zoning laws, the results indicate 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. Minimum floor area requirements should be eliminated as additional floor area directly relates to greater electricity use.
Monthly electricity use data revealed that detached households had higher electricity use per unit floor area in the cooling and heating seasons but about the same during the swing seasons. The percent change from average monthly electricity use to the peak winter month electricity use was much higher in the detached households than in the attached households.
Detached households drove 48% more miles than attached households, however the differences are largely due to increased occupancy in detached households. As occupancy increases, miles per occupant decreases. Comparing households with equal number of occupants showed that attached households drive slightly fewer miles per year. On a per driver or per automobile basis the reported mileage was almost equal between attached and detached households.
Averaged distances to work, schools and all but one errand trip were shorter for attached households. A large majority of all trips were accomplished by automobile. Less than 1% of school children bicycled or walked to school. Only 27% of the school children live within two miles of the school they attend.
Twice as many attached household workers lived within five miles of work as detached household workers. Average miles traveled to work and back each week was 8.6% greater for a worker living in a detached household. Forty-nine percent of the reported miles driven in attached households were due to work trips, relative to 39% for detached households.
Forty-seven percent of attached households as opposed to 17% of detached households have someone who rides a bicycle or walks to a store or recreational area.
13.0 Further Research and Analysis
The collected data is for a small group of land developments built in the 1980's in central Florida. To generalize conclusions reached in this study, more households need to be analyzed. This might include:
∙ non-responding households in the ten developments;
∙ randomly selected households of all 1980s East-Central Florida residential
land developments;
∙ similar households in a larger region of the state or throughout the
entire state;
∙ older attached and detached households;
∙ reexamination of the same developments in ten years (e.g., transportation
distances may be reduced with time as new commercial areas follow residential
development).
A number of questions were raised by our analysis. They include:
∙ How can legal barriers to energy-efficiency, such as separate
zoning and minimum square-footages be removed or improved?
∙ How can we encourage bicycling and walking 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? [FSEC is being funded by the Governor's Energy Office through the Department
of Community Affairs to investigate]. How would such savings compare to other
efficient hot water heating methods?
∙ How much electricity do different pool/spa-heating devices use and
what is the impact on the state's total residential energy use?
∙ What are some acceptable alternatives to turfed lawns for households?
14.0 Acknowledgements
FSEC is thankful of the Governor's Energy Office for funding the study and permitting the use of their envelopes for conducting the survey. Questionnaire mailing, receiving and coding was performed by Behavioral Science Research in Coral Gables, Florida, under the direction of Dr. Robert Ladner and Rohit Vaidya. Special thanks to Florida Power and Light, and Florida Power Corporation, for contributing time and effort in obtaining the utility data for each of twelve months for respondents in their territory. Assistance in developing the survey was provided by Larry Maxwell of FSEC. Wanda Dutton of FSEC helped collect water information and type many drafts of the survey and this report. Junaid Alim and Nick Drake of FSEC helped with research, data coding and report preparation.
Check out: Appendix A