This page describes how the Energy Estimates generated by the Home Energy Saver enegy calculations are use to estimate cost estimates.
The basic calculation of energy bills is given in the following equation:
Annual Cost = Annual site energy * utility conversion[resource] * price[resource]
Where resource is one of electricity ,natural gas ,fuel oil, or lpg
The site units and conversion factors are given in table 1.
| Table 1. Site Cost Units and Utility Conversion Factors |
| Fuel |
Primary Units
|
Utility Units US
|
Conversion US
|
| electric |
kWh |
kWh |
1 |
| demand |
watts |
kW |
0.001 |
| natural gas |
kBtu |
therms |
0.01 |
| lpg |
kBtu |
gallons |
0.01092 |
| fuel oil |
kBtu |
gallons |
0.00722 |
| cold water |
gallons |
gallons |
1 |
| hot water |
gallons |
gallons |
1 |
| carbon |
lbs co2 |
lbs co2 |
1 |
| currency |
$ |
$ |
1 |
| heat flow |
kBtu |
kBtu |
1 |
| all |
N/A |
N/A |
0 |
| source |
kBtu |
mBtu |
0.001 |
When a building is first created default energy prices are assigned based
on the state in which their ZIP code is located. The defaults energy prices are presented in table 2 below. Users have the option of overriding these values with their own utility rates. The default energy prices
are the most recent available state averages from either 2009 (for electricity
and natural gas) or 2007 (for LPG and fuel oil). Energy price data are from the U.S. DOE's Energy Information Administration (US
DOE 2007, 2009a, 2009b, 2011), and U. S. EPA 2009, 2012.
| Table 2. Default Energy Prices |
| State |
Electricity Price |
Natural Gas Price |
LPG Price |
Fuel Oil Price |
| Alabama |
0.113 |
1.581 |
2.342 |
1.957 |
| Alaska |
0.176 |
0.889 |
3.069 |
2.503 |
| Arizona |
0.111 |
1.587 |
2.824 |
2.459 |
| Arkansas |
0.091 |
1.153 |
2.171 |
1.994 |
| California |
0.152 |
0.992 |
2.566 |
2.516 |
| Colorado |
0.113 |
0.813 |
2.073 |
2.111 |
| Connecticut |
0.181 |
1.493 |
2.915 |
2.637 |
| Delaware |
0.137 |
1.512 |
2.571 |
2.422 |
| Florida |
0.117 |
1.789 |
3.096 |
2.390 |
| Georgia |
0.111 |
1.517 |
2.252 |
2.344 |
| Guam |
0.347 |
4.450 |
4.572 |
2.422 |
| Hawaii |
0.347 |
4.450 |
4.572 |
2.422 |
| Idaho |
0.079 |
0.895 |
2.260 |
2.171 |
| Illinois |
0.118 |
0.939 |
1.849 |
2.290 |
| Indiana |
0.101 |
0.862 |
2.148 |
2.342 |
| Iowa |
0.105 |
0.957 |
1.807 |
2.237 |
| Kansas |
0.106 |
1.054 |
1.890 |
2.223 |
| Kentucky |
0.091 |
1.002 |
2.269 |
2.237 |
| Louisiana |
0.091 |
1.173 |
2.581 |
1.957 |
| Maine |
0.154 |
1.414 |
2.907 |
2.501 |
| Marshall Islands |
0.347 |
4.450 |
4.572 |
2.422 |
| Maryland |
0.134 |
1.244 |
2.836 |
2.621 |
| Massachusetts |
0.148 |
1.453 |
3.008 |
2.488 |
| Michigan |
0.131 |
1.132 |
2.323 |
2.222 |
| Minnesota |
0.110 |
0.876 |
1.943 |
2.266 |
| Mississippi |
0.101 |
1.019 |
2.565 |
2.014 |
| Missouri |
0.098 |
1.166 |
1.864 |
2.200 |
| Montana |
0.098 |
0.864 |
1.921 |
2.053 |
| Nebraska |
0.093 |
0.895 |
1.615 |
2.227 |
| Nevada |
0.116 |
1.225 |
2.720 |
2.484 |
| New Hampshire |
0.165 |
1.446 |
2.605 |
2.377 |
| New Jersey |
0.162 |
1.284 |
3.195 |
2.573 |
| New Mexico |
0.110 |
0.963 |
2.332 |
1.976 |
| New York |
0.183 |
1.404 |
2.806 |
2.605 |
| North Carolina |
0.103 |
1.250 |
2.480 |
2.365 |
| North Dakota |
0.086 |
0.808 |
1.640 |
2.216 |
| Ohio |
0.114 |
1.113 |
2.474 |
2.247 |
| Oklahoma |
0.095 |
1.113 |
1.859 |
2.207 |
| Oregon |
0.096 |
1.249 |
2.543 |
2.132 |
| Palau |
0.347 |
4.450 |
4.572 |
2.422 |
| Pennsylvania |
0.134 |
1.290 |
2.719 |
2.470 |
| Puerto Rico |
0.347 |
4.450 |
4.572 |
2.422 |
| Rhode Island |
0.145 |
1.648 |
3.503 |
2.542 |
| South Carolina |
0.111 |
1.303 |
2.623 |
2.390 |
| South Dakota |
0.093 |
0.877 |
1.684 |
2.195 |
| Tennessee |
0.098 |
1.046 |
2.556 |
2.259 |
| Texas |
0.113 |
1.081 |
2.419 |
2.000 |
| Utah |
0.090 |
0.822 |
2.036 |
2.148 |
| Vermont |
0.163 |
1.614 |
2.771 |
2.749 |
| Virgin Islands |
0.347 |
4.450 |
4.572 |
2.422 |
| Virginia |
0.107 |
1.273 |
2.660 |
2.302 |
| Washington |
0.083 |
1.224 |
2.161 |
2.653 |
| Washington DC |
0.134 |
1.353 |
2.755 |
2.571 |
| West Virginia |
0.094 |
1.139 |
2.565 |
2.401 |
| Wisconsin |
0.131 |
1.034 |
1.987 |
2.211 |
| Wyoming |
0.091 |
0.858 |
2.148 |
2.134 |
| 