The fuel comparison calculator for home heating can be used for estimating and comparing costs of different heating fuels. It is very important that you use the correct values for a reliable estimate. This is particularly important when estimating wood, please see the notes below for further details.
BTU or British Thermal Unit is the amount of heat needed to raise the temperature of one pound of water by one degree Fahrenheit. Fuels like oil and natural gas can have minor differences in their BTU content but it's a negligible amount. The BTU content in solid fuel on the other hand can vary widely.
Lignite coal which is lowest grade of coal may only have 14 million BTU's per ton, the highest quality anthracite can exceed 28 million. You can expect about 24 to 25 million BTU's per ton on average from anthracite coal.
The BTU content of wood is particularity problematic in these estimates. Pound for pound wood has about the same BTU content regardless of species however wood is sold by volume therefore one cord of soft wood will have a lower BTU content than hardwood. The other issue with estimating wood is the moisture content which can vary widely. High moisture content can drastically affect the efficiency. The default values of the calculator assume a seasoned hardwood.
Fuels that burn like coal, natural gas, oil and wood have heat loss out of the chimney. That heat loss is accounted for using the efficiency column. Consult the manufacturer's documentation to find out what the efficiency of your particular heating unit is.
Per 100 Million BTU
This is the adjusted cost based on the values in the calculator, it will automatically update as you change values. The average home in the Northeast US may need 100 million BTU's for a heating season. An average home would be 2000 sq. ft., newer windows and reasonably insulated. On avergae most homes that fit this criteria use 4 to 5 tons of anthracite coal per heating season.
Geothermal and Air Sourced Heat Pumps
Geothermal and air sourced heat pumps use electric to mechanically extract "free" heat from the groundwater or the air. Since electric is the only fuel cost in this calculation we use that as the base for costs and why it can exceed 100%. If a geothermal or air sourced heat pump uses half the electric to produce the same amount of BTU's the efficiency would be 200%.
Groundwater temperatures are fairly consistent especially for deep wells so that does not play much of a factor in determining efficiency. The temperature of the air on the other hand varies widely and this can have a very big impact on the efficiency. For air sourced heat pumps when comparing to resistance electric heat you can have efficiencies as high as 280% during mild weather down to the same costs as electric where the auxiliary heat will kick in.
Electric Heaters Advertised on TV
Please do not be deceived, they use electric which produces 3,412 BTU's per kWh. This number does not change whether it's a light bulb, hair dryer, cheap electric heater from the box store or the very expensive heaters advertised on TV. The only thing that differs about any of these heat sources is how they distribute the heat. A 1200 watt heater from the box store is going to put just as much heat into the room for the same cost as one advertised on TV and will similarly distribute the heat if it has a fan. You could literally use twelve 100 watt incandescent light bulbs distributed throughout a room to produce the same amount of heat as any 1200 watt electric heater and if wasn't for the addtional cost of replacing the light bulbs it would be feasible.
Setting aside heat pumps electric heat is typically the most costly heat source. You may save money with a portable electric heater under very limited conditions. If you have a large zone controlled by one thermostat you may save money by turning down the main thermostat and using the portable electric heater in the room you want heated. This is particularity true if your primary heat has a high cost per BTU like electric or oil.
If your primary heat is a low cost per BTU fuel like coal or natural gas you savings could be negligible, none or even cost you money depending on your particular household. The cost to heat three or four rooms with lower cost fuels may be the same to heat one with electric. Furthermore if you already have a multi-zone sytem you already have all the benefits a portable heater can provide. If you do not have a multi-zoned sytem invest in that instead.
These calculations only take into account the cost for the fuel. Pumps on boilers or fans on furnaces used to distribute the heat will increase your costs. If you have boiler or furnace and intend on replacing it with another boiler or furnaces using a different fuel these additional cost will be about the same so it's not much of a consideration. On the other hand fired coal stoves or boilers that use gravity or convection to distribute the heat do not have these additional costs.
Ethanol, Fireplace gel and US Currency
Both the ethanol and fireplace gel costs are accurate. The costs per unit were obtained from the listed prices of major US retailers. While these types of fireplaces may be desirable for ornamental purposes as a heat source it should not be a consideration. While the costs to burn money is accurate as well that of course was added for a little humor and now you know what it would cost to burn money to heat your house.