| Preface |
| One of my main arguments during college energy studies in 1983-4 was that better understanding of energy usage was essential not only for educating and motivating households to reduce their energy consumption, but also for developing the most insightful perspectives among policy-makers, energy consultants, designers and builders to assist and guide clients toward reasonable goals. Almost 20 years later, I still find that most homeowners, builders and designers do not commonly know very well how their homes’ energy consumption compares with others. So it has been one of my periodic habits to retrieve and review my clients’, friends’ and associates’ energy consumption. By staring that data and my commentary about it, I hope to provide generally needed education and guidance about what is typical and achievable for household energy usage in SW Ohio, SE Indiana and Northern Kentucky. |
| 2001 Survey Introduction |
| During early 2002, I sent emails to many SW Ohio, SE Indiana and Northern Kentucky households requesting home energy data for 2001. I also requested information about number of occupants, conditioned floor area and general location. I did not ask about housing styles and specifications, occupant habits or internal equipment, but I did know or learn some information about the majority of the eventual respondents, since I had visited 12 of them in recent years. A few responses included information about the house, its contents and occupants. When this report was written, responses had totaled 25 out of many times that in requests. I had compiled the data without verification. Five households had superinsulated and/or passive solar homes designed by me. One other household was my own, an older home remodeled for much better efficiency and passive solar. The rest included a few in new homes, but most were in older housing, only some of which had been remodeled to improve energy performance. |
| Electricity was the only energy type common to all the surveyed households, and it also had the greatest high/low ratio from one household to another, almost 12:1. Ten households used natural gas and nine burned wood. There was only one house which used both natural gas and wood, and that one household not only had the lowest overall energy cost in 2001, $566, but also the lowest annual electricity consumption, 2930 kWh. The household with the highest overall energy bill, $3612, also had the highest annual electricity usage, 34,510 kWh. Interestingly, these 2 households were each owned and occupied by retirees. Also interesting is that these 2 households beat the next closest annual energy-cost households (at both the least and most ends of the scale) by about 3:2. |
| Analyzing 2001 Energy Performance |
| Since house size and the purposes or tasks accounting for energy consumption are typically so varied from household to household, it is helpful when doing comparisons to index data to useful common denominators. ‘Per-sf’ indices (i.e., Btu/sf, $/sf, CO2/sf) are often used by designers and engineers to rate building and equipment designs for efficiency. Three surveyed households in newer, well-insulated homes in this survey demonstrated the lowest annual energy usage per conditioned floor area, 16-19 kBtu/sf, while three other households in different newer, well-insulated homes had the lowest annual CO2 emissions demand per floor area, 7.8 - 8.5 #/sf. Two of the households with the lowest energy/sf and another household with the lowest CO2/sf showed how low local home energy costs could be in 2001 per floor area, $0.35 - $0.39/sf. Four of these 6 best performers were insulated substantially beyond code requirements, using foam-filled wall systems instead of fiberglass-filled stud cavities. Another was a strawbale-wall house. Most were at least partly passive solar. Only 2 used natural gas. Four had all-electric utilities. One had geothermal HVAC. Four of the 6 homes combined used less than ½ cord of wood, so cheap fuel did not account for low energy costs. |
| Three households in older, thermally unimproved homes had the highest annual energy usage per floor area, 83-103 kBtu/sf, while 3 other households in different older homes had the highest annual CO2 indices per conditioned floor area, 27-39 #/sf. Two of the highest-CO2/sf households were all-electric and the other had the highest electricity use in the survey, so it seems that high-CO2 indices were associated with greater electricity use in average-to-poor thermal building envelopes. The reason why the 3 highest-Btu/sf homes were not also highest in CO2/sf is likely because their primary heating energy was natural gas, which produces less CO2 per Btu than electricity generated from coal. One high energy/sf and two high CO2/sf households demonstrated how high less thermally improved homes’ energy costs could be in 2001, $1.16 -$1.27/sf. |
| ‘Per-person’ indices (i.e., CO2/person, $/person, SF/person) are less familiar, but these are helpful for gauging energy and environmental performance per person instead of house size. I included a ‘Sf/person’ index since home floor area per person, called "occupant density", varied over 8:1 in this survey. One of the 3 highest occupant-density households achieved some of the lowest $/person and mBtu/person ratings, even though its home’s walls were built with logs and the home contained very few building-related prescriptions normally associated with super-efficient housing. It is noteworthy that all 3 households with the lowest CO2 emissions, 4866 to 5992 #/person, also had high occupant density, 550-625 sf/person. The 2nd highest CO2/person index, 18,799#, occurred in the household with the lowest occupant density, 2002 sf/person, in the same all-electric house which had the lowest total energy consumption per floor area, demonstrating how per-person energy and environmental ratings can be quite different from per-sf ratings. All 3 households with highest CO2/person had lower-than-average occupant density and higher-than-average electricity usage. |
| The difference between the 3 highest and 3 lowest per-sf household energy costs in this survey averaged $0.845/sf. If applied to this survey’s home size average of 2314 sf, this potential energy cost difference for 2001 would be $1955.33 per home. |