Fuel Cost Comparison
Comparing the cost of heating with GeoExchange
to other heating methods

How does the cost of heating with a GeoExchange compare to other heating methods?

The answer to this depends on local rates for electricity and other fuels. The comparison involves the efficiency of the device, the type of fuel used and the cost of that fuel.

Commonly used heating fuels have the following approximate heating content:

Fuel oil - 138,000 Btu/gal
Propane - 90,000 Btu/gal
Natural gas -100,000 Btu/therm(1,000 Btu/ft³)
Electricity - 3,413 Btu/kWh

A common index of the cost of heat is "dollars per 1,000,000 Btu of useful heat." In order to calculate useful heat (heat actually delivered to the house), it's necessary to adjust for the efficiency of the heating device and the cost of the fuel. The following equations can he used for this purpose:

Fuel oil	7.25 x $/gallon efficiency	Efficiency Old - .65 New std. - .78 Moderate - .84 High - .92
Propane	11.1 x $/gallon efficiency
Natural gas	10.0 x $/therm efficiency
Electric resistance	293 x $/kWh
Air Source Heat Pump (ASHP)	293 x $ /kWh COP	COP Warm climate - 2.5 Cold climate - 1.8
Ground Source Heat Pump (GSHP)	293 x $ /kWh COP	COP Warm climate - 3.9 Cold climate - 3.4 Hydronic - 4.2

As an example, let's look at a location in a moderately cold climate where the fuel costs are as follows:

Electricity, $0.07/kWh; fuel oil, $1.05/gal; propane, $1.20/gal; and natural gas, $0.60/therm. This would result in the following useful heat costs:

Electric resistance	20.51
Propane	15.86
ASHP	9.54 (2.15 COP)
Fuel oil	9.06
Natural gas	7.14
GHP	5.86 (3.5 COP)

 

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