The following was originally posted by Swany, in the Pro's Forum.
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I got this years ago from the utility company. I keep it around to do utility cost comparisons with current rates here locally. These are our current rates, fuel oil is a guess since there isn't any here. I just use the current price per gallon of diesel.
On the efficiency calculations, use your own equipment ratings for AFUE, COP and Efficiency.
Converting Fuel to Therms and Comparing Cost
1 Therm = 100,000 Btu
Natural Gas = 1000 Btu/Ft3
LP Gas = 91,500 Btu/Gal
#2 Fuel Oil = 140,000 Btu/Gal
Electricity = 3,415 Btu/KW
Natural Gas
Natural Gas is usually priced per CCF (100 FT3) which is 1 Therm. Calculations usually are based on 10 Therms or 1,000,000 Btu’s (MMBtu).
Example: Typical current natural gas rate of $1.25/Therm will be $12.50/MMBtu.
LP Gas
LP Gas is priced per gallon which is 91,500 Btu. A Therm of LP Gas (100,000 Btu) is 1.09 Gallons.
Example: Typical current LP gas price of $1.25/Gallon will be $1.32/Therm of $13.20/MMBtu.
#2 Fuel Oil
Fuel Oil is priced per gallon which is 140,000 Btu. A Therm of Fuel Oil (100,000 Btu) is .714 Gallons.
Example: Typical current #2 Fuel Oil price of $2.29/Gallon will be $1.64/Therm or $16.40/MMBtu.
Electricity
Electricity is priced per KWH. There are 3,415 Btu per KW. A Therm of Electricity (100,000 Btu) is 29.28 KW.
Example: Typical current electric rate of $.08/Kwh will be $2.32/Therm or $23.20/MMBtu.
Fuel Cost vs. Efficiency
• Natural Gas @ $12.50/MMBtu = $12.50/.80* = $15.63
• Natural Gas @ $12.50/MMBtu = $12.50/.90* = $13.89
• LP Gas @ $13.20/MMBtu = $13.20/.80* = $16.50
• LP Gas @ $13.20/MMBtu = $13.20/.90* = $14.67
• Fuel Oil @ $16.40/MMBtu = $16.40/.80* = $20.50
• Electricity @ $23.20/MMBtu = $23.20/1.0* = $23.20
• Heat Pump @47° With a COP of 3.86* = $23.20/3.86 = $5.32
• Heat Pump @17° With a COP of 2.36* = $23.20/2.36 = $9.83
*AFUE, Fuel Efficiency or C.O.P.
Using the above formulas, convert to your current rates of Natural Gas, LP Gas, Fuel Oil and Electricity. In some areas, when converting to or adding a heat pump, lower electric rates will apply. Be sure to use those rates in this formula.
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Your prices are a little different (fuel oil and KWH), but it looks like there should be savings for you. Depending on what it costs to put the new system in, you might not break even on the cost of the install for a few years. I think it would be worth your time to talk to your contractor about it. If you wanted, you should be able to use your existing oil furnace as the backup heat. This would also help lower the overall cost of the install.
Here is another link to some info on heat pumps http://energyoutlet.com/res/heatpump/efficiency.html
What's my post count now?
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