Fuel Comparison Calculator

This calculator provides a way to compare the cost for various fuels types.


The calculator estimates the cost for each fuel type to deliver 100,000 BTU's of heat to your house. 

The calculator takes into account the cost of the fuel, energy content of the fuel, and the efficiency of your furnace.



For all the fuels you are interested in:

Fill in the "Fuel Cost per unit" -- this is what you pay in dollars for the fuel unit listed.  For example, if you pay $2.50 per gallon for propane, then type 2.50 into the Fuel Cost column for Propane.  Make sure you fill in the price for the unit size listed -- for example, wood is $'s per cord, not $'s per bushel.


Fill in the "Efficiency" column for the furnace or heat plant you will use.   For example if you have a 95% efficient condensing NG boiler, you would fill in 95 in the "Efficiency" column for Natural Gas.


After filling in the data for the fuels you are interested in, click on the "Calculate" button.

The cost to produce 100,000 BTU of heat will be listed for each fuel in the "Real Heating Cost" column.

This provides an "apples to apples" comparison of real fuel costs, since all fuels are delivering the same amount of energy.



Fuel Type Fuel Cost per unit Approx BTU heat for the different fuel types Normal Cost for
100000 BTU
Efficiency (%) of Burner Real Heating Cost
for 100000 BTU after efficiency Calculated
Natural Gas $/therm(ccf)
Propane $/gallon
Fuel Oil $/gallon
Kerosene $/gallon
Electricity Resistance $/KWH
Electricity - Heat Pump $/KWH
Wood $/cord
Wood - Pellets $/ton
Coal $/ton



- Default prices have been provided. You need to substitute prices for your area.


- Note that for wood, the unit is a full cord of wood -- 4 ft X 4 ft X 8 ft = 128 cubic ft of wood.  Wood is sold in a confusing array of sizes, so be sure to get prices for a full cord.


- Furnace efficiencies are mostly from the EERE site.  They do not include losses in heating ducts



- Heating values for the fuels used in the calculator are:    These are primarily from the EERE site.

Natural Gas             103,700 BTU per therm or CCF  (note that some sources list a CCF at a lower value)

Propane gas             91,500 BTU per gallon

Fuel Oil                   138,500 BTU per gallon

Electricity                3413 BTU/KWH

Soft Woods             15 million BTU/full cord

Hard Woods            22 million BTU/full cord

Wood Pellets           16.5 million BTU/ton

Coal         `               25 million BTU/ton (anthracite)


- The coal numbers are for anthracite coal.

- Efficiencies of all burners and furnaces vary greatly -- especially the wood burners. Wood burners can be as low as 5% for open wood fireplaces up to 80% for the latest EPA certified wood burners.

For propane and NG furnaces, I've used an up to date non-condensing furnace (85%). New models of condensing furnaces can be up in the 90% to 97% area.

For wood stoves, I've used the Hearth.com efficiency number for "Newer EPA non-catalytic stoves" of 60%. Older. Older, non EPA certified stoves could be as low as 35%, while new EPA certified catalytic stoves could be up to 72%.