Released September 14, 2009
ORONO, Maine --Are you thinking of replacing your heating system or installing supplemental heating? If so, you will need to know how to compare the cost and value of different heating fuels. There are four different variables you must work with to determine which fuel provides the most heat for the fewest dollars: the type of heating fuel, the unit cost of the heating fuel, the per-unit energy content (Btu) of the fuel, and the efficiency (AFUE) of the heating unit.
Different fuels provide different amounts of energy or heat. So to begin, you need to know the approximate heating value of commonly used heating fuels:
Kerosene (no. 1 fuel oil) 135,000 Btu per gallon
Burner fuel (no. 2 oil) 138,500 Btu per gallon
Electricity 3,413 Btu per Kwh
Natural gas 100,000 Btu per therm
Propane 92,500 Btu per gallon
Hardwood (20% moisture) airtight 24,000,000 Btu per cord
Hardwood (20% moisture) catalytic converter 24,000,000 Btu per cord
Pine (20% moisture) airtight stove 15,000,000 Btu per cord
Pine (20% moisture) catalytic converter 15,000,000 Btu per cord
Wood pellets in a pellet stove 16,000,000 Btu per ton
Let’s assume that you are deciding between two different heating systems. One uses wood pellets as the heating fuel, and the other uses no. 2 fuel oil. Let’s further assume that the wood pellet stove has an AFUE of 80 percent, while the oil-fueled system has an AFUE of 65 percent. You have called several fuel suppliers in your area and have learned that the average price of a ton of wood pellets is $282, and the average price of a gallon of oil is $2.34. So how do you figure out which will provide the most heat for the fewest dollars? You can directly compare these systems by calculating your cost per million Btu (MBtu), using this formula:
Multiply the unit cost of the fuel by 1 million Btu. Divide the result by the amount of Btu per unit of fuel. Then divide once again, this time by the AFUE of the heating appliance:
Unit cost of oil = $2.34 per gallon
Heat value/Btu of oil = 138,500 Btu per gallon
AFUE of the oil-fueled heating appliance = 65%
$2.34 x 1,000,000 = 2,340,000
2,340,000¸ 138,500 = 16.90
16.90¸ .65 = $26 per million Btu
Unit cost of wood pellets = $282 per ton
Heat value/Btu of pellets = 16,000,000 Btu per ton
AFUE of the pellet-fueled heating appliance = 80%
$282 x 1,000,000 = 282,000,000
282,000,000 ¸ 16,000,000 = 17.63
17.63 ¸ .80 = $22.04 per million Btu
Using these calculations, you can see that this particular oil-fueled heating unit will cost you $26 per million Btu, while this particular pellet-stove will cost you $22.07 per million Btu. So in this case, the pellet stove provides more heating value per dollar.
As you can see, calculating and comparing the cost per MBtu provides a way to compare the value of heating fuels sold and priced by very different units of measure. Knowing the best fuel value, along with installing the most efficient heating appliance you can, can significantly reduce your heating costs.
University of Maine Cooperative Extension’s bulletin “How Much Heat Per Dollar?” includes a heating fuel cost-equivalence chart, as well as a cost calculator, to help make these comparisons easier. The bulletin is part of the Maine Home Energy series, available at http://extension.umaine.edu or 800-287-0274.
(Excerpted and adapted from How Much Heat Per Dollar, bulletin #7216 from University of Maine Cooperative Extension, http://extension.umaine.edu. Heating values of fuels from John Bartok, Approximate Heating Value of Common Fuels [Storrs: University of Connecticut, 2004].)
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http://extensionnews.blogspot.com/2009/09/how-to-compare-new-heating-systems.html
Media contact: Jennifer O'Leary, (207) 353-5550, joleary@umext.maine.edu
