Comparing Values of Various Heating Fuels

It is time to replace that ancient heating system in your basement. What type of new heating system should you buy? While there are several factors you will want to consider and compare before making your decision, one of the very first factors you should consider is about what type of heating fuel to use. To help you make that decision, this fact sheet outlines calculations you can use to determine which type heating fuel is the best value. There are four different variables you will be working with as you do the calculations to determine which fuel provides the most heat for the fewest dollars.

These are

1. The type of heating fuel
   Many choices are available, natural gas, electricity, fuel oil, propane and wood are common fuels used in Maine.
    

2. The unit cost of the heating fuel
   hat is, the amount of money the fuel costs per unit of measure it is typically sold by. Fuel oil, a liquid, is typically sold by the gallon, stick wood, a solid material, by the cord, and wood pellets are sold by the ton.
    

3. The per unit energy content of the fuel (measured in Btu's)
   Btu, an abbreviation used for the term British thermal unit, is a measure of heat energy. One Btu is equal to the amount of heat required to raise the temperature of one pound of water by 1 degree Fahrenheit. Different fuels produce different amounts of heat energy when burned. For example one gallon of kerosene will produce 135,000 Btu's of energy when burned, one gallon of propane 92,500 Btu's, and one ton of wood pellets will produce 16,000,000
    

4. AFUE: The overall efficiency of the heating unit you use
   Annual Fuel Utilization Efficiency (AFUE) is expressed as a percentage. It is a measure of how effectively a heating system turns heat released from burning fuel into heat you can use to warm your home. No heating system converts 100% of the fuels energy into heat for your house. All heating systems will lose some heat due to start-up, cool-down, and heat escaping up the chimney with combustion gasses. New and efficient heating systems should have an AFUE of 85% or higher. Few systems have AFUE's above 95%.

Example

Lets assume, you are deciding between two different heating systems. One uses wood pellets as the heating fuel, the other uses Burner oil (number two fuel oil). Lets further assume that the wood pellet stove has an AFUE of 80%, while the oil fueled system has an AFUE of 85%. You have called several fuel suppliers in your area and have learned that the average price of a ton of wood pellets is $230, and the average price of a gallon of oil is $4.30. You determine the cost for wood pellets is $18 per million BTUs (MBTU) and cost for oil is $36 per MBTU by referring to Table 1.

An interesting comparison of an oil burning furnace with 65% efficiency compared to the 85% oil furnace shows the less efficient furnace costs $48 per MBTUs compared to the $36 per MBTU. Also, burning stick seasoned hardwood in a wood stove rated at 50% efficiency yields a cost of $20 per MBTU.

Download an Excel spreadsheet with formulas that will enable you to calculate your own fuel cost with your specific numbers.

Adapted by Donna Coffin, University of Maine Cooperative Extension Educator. Reviewed by Gleason Gray and Kathy Hopkins, University of Maine Cooperative Extension Educators.

For more energy-saving tips, see Energy-Saving Tips.

Published and distributed in furtherance of Acts of Congress of May 8 and June 30, 1914, by the University of Maine Cooperative Extension, the Land Grant University of the state of Maine and the U.S. Department of Agriculture cooperating. Cooperative Extension and other agencies of the U.S.D.A. provide equal opportunities in programs and employment.  Call 800-287-0274 or TDD 800-287-8957 (in Maine), or 207-581-3188, for information on publications and program offerings from University of Maine Cooperative Extension, or visit www.umext.maine.edu. 2008