Furnace Fuel Cost Comparison

The common denominator when determining the cost of a fuel is the “ British Thermal Units”  (BTU) the fuel gives off.

Fuels are sold in different forms, such as kilowatt-hours for electric, cubic feet for natural gas and gallons for oil or liquid petroleum.

With standard fossil fuel appliances, you need a chimney.  The losses at the burner and up a chimney are significant.

The formula:

Fuel x Cost + Waste = Net Cost.

Natural Gas

103,000 BTUs x .90 per CCF + .30 (30% waste) = 1.20 to Net 103,000 BTUs of heat.

Electric

3412 BTUs x .14 per kWh + 1% or less waste = .14 to Net 3412 BTUs of heat.

Oil

134,500 BTUs x .85 per gallon + 40% waste = 1.19 to Net 134,500 BTUs of heat.

Liquid Petroleum

92,000 BTUs x 1.00 per gallon + 30% waste = 1.30 to Net 92,000 BTUs of heat.

Once you have the breakdown of fuel costs in BTUs, you can compare any fuels.

Gas Compared To Electric:

103,000 BTUs (CCF of natural gas) divided by 3412 BTUs (1 kWh of electric) = 30.18.

100 CF of natural gas delivers 103,000 BTUs for 1.20 including waste.

30.18 kilowatt-hours of electricity deliver 103,000 BTUs for 30.18 x .14 or 4.22.

Based on these figures, electricity in this area is approximately 350% more than the cost of the natural gas for the same amount of net heat.

4.22 divided by 1.20 = 3.50

The exception is when the house is all-electric or the primary heat is electric, such as an electric heat pump. The electric utility company discounts the residential electric rate to approximately 2/3 of the whole rate. This applies to the entire house.  In most areas, the discounted rate is only for the heating season.

Example: If there is a discounted rate of about .095 per kWh, the heat pump is operating above the balance point, and the compressor is modern with a COP or coeficiency of performance that is close to 3.0; the cost to operate will be approximately .032 per kWh

When compared to a standard 67% efficient gas heating appliance using about 1.20 per ccf, the heat pump cost will be less than the gas appliance.

30.18 x .032 = .965 compared to 1.20.

This is good until the outside temperature drops below the balance point, or about 35 degrees Fahrenheit. When the outside temperature is below the balance point, the heat pump back-ups come on and provide electric resistance heat at the straight-line electric rate. This will be 2.5 to 3 times the cost of the electric used through the heat pump compressor.

Other:

The household electric appliances are also impacted by the cost of the electric. There is no situation where an electric appliance will be less expensive to operate than a gas appliance, however, there may be a few areas in the northwest part of the country where electric costs are less.

Oil Compared To Electric

134,500 BTUs (one gallon of oil) divided by 3412 BTUs (1 kWh of electric) = 39.4

1 gallon of fuel oil delivers 134,500 BTUs for 1.19 including waste.

39.4 kilowatt-hours of electricity deliver 134,500 BTUs for 39.4 x .14 or 5.51.

Based on these figures, at the present time, electricity in this area is approximately 463% times the cost of fuel oil for the same amount of net heat.

5.51 divided by 1.19 = 4.63

Fuel Oil Cost Compared To Natural Gas

134,500 BTUs (one gallon of oil) divided by 103,000 BTUs (100 cubic feet of gas) = 1.30

1 gallon of fuel oil delivers 134,500 BTUs of heat for 1.19 including waste.

1.30 CCF (100 cubic feet) of natural gas delivers 134,500 BTUs of heat for 1.56 including waste.

Based on these figures, at the present time, gas in this area is approximately 31% more than the cost of fuel oil for the same amount of net heat.

1.56 divided by 1.19 = 1.31

You may use this formula to compare any fuel you can think of if you know the BTUs, cost and waste of any fuel and equipment we may use.

It is probably obvious to everyone, but my suggestion is to use gas (natural or liquid) and/or oil for appliances (ranges, ovens, water heaters or dryers) and heating equipment.