Based on the type of heating source you input, we used the following formulas:
Electricity Emissions = (average monthly electric bill / price per kWh) * electricity emission factor * months in a year
We assumed a national average US price per kWh = $0.1
We used an electrical emission factor (electricity/kWh) = 1.37 [Source: Energy Information Administration (EIA). Electric Power Annual 2005, Table 5.1 (October 2006)]
Natural Gas Emissions = (average monthly gas bill / price per thousand cubic feet) natural gas emission factor * months in a year
We assumed a national average US price per thousand cubic feet = $13.83 [Source: Energy Information Administration (EIA): Natural Gas Annual]
An emission factor (natural gas/thousand cubic feet) = 120.61 was used. [Source: U.S. EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2004, Annex 2,Table A30]
Fuel Oil Emissions = (average monthly fuel oil bill / price per gallon) fuel oil emission factor * months in a year
A national average of $2.37 per gallon was used. [Source: Energy Information Administration: US No. 2 Distillate Prices by Sales Type, Table 15.]
Our emission factor used was (fuel oil/gallon) = 22.28 [Source: U.S. EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2006, Annex 2, Table A30]
