Compare the cost of heating with wood to using alternative heating options. The calculation is based on the amount of Btu's one cord of firewood potentially can produce to the equivalent amount needed when using propane or electricity for heating and what it cost you for a cord of firewood.

In general, when calculating the efficiency of a heating appliance the Higher Heating Value (HHV) is used in the calculation of the amount of fuel used for burning. This does not make much sense if you consider that this amount is impossible to achieve in units used for residential heating.

HHV of propane = 91420 Btu per gallon US
LHV of propane = 84250 Btu per gallon US

Example Calculation:

• one cord of firewood that produces 24 Mbtu @ cost of $400.00 per cord
• wood appliance burning efficiency = 78%
• propane Btu's per gallon = 84250 Btu
• propane cost per gallon = $3.50
• propane burning efficiency = 85%
• cost of electricity in cents per kWh = 12 cents
• one kWh = 3412 Btu
• electrical appliance efficiency = 100%

Firewood:

24 * 0.78 = 18.7

A cord of firewood produces 18.7 million of Btu's at a cost of $400.00

Propane:

84250 * 0.85 = 71,612.5
18.7 * 1000000 ÷ 71,612.5 = 261 gallons

It takes 261 gallons of propane to produce 18.7 Mbtu

261 * 3.50 = 913.95

Cost for using propane = $913.95

Electricity:

18.7 * 1000000 ÷ 3412 = 5,480.66

It takes 5,480.66 kWh to produce 18.7 Mbtu

5,480.66 * 0.12 = 657.68

Cost for using electricity = $657.68

In the Calculations:

• it is assumed that you know the price of a cord of firewood
• the preset value of 84250 Btu's per US gallon of propane, can be changed
• one kWh of electricity = 3412 Btu
• electrical heathing efficiency preset @ 100%, can be changed

The Calculation

1. enter the amount of Mbtu's your firewood can produce. Choose from the list below or use your amount
2. the efficiency of the wood-burning appliance in a percentage
3. the heating value of propane per gallon in Btu's preset @ 84250 Btu
4. price of propane in an amount per gallon
5. propane appliance burning efficiency rated Annualized Fuel Utilization Efficiency or AFUE level
6. cost of electricity in cents per kilowatt-hour
7. electrical appliance efficiency, preset @ 100%

Results

1. amount of Btu's from firewood based on burning efficiency
2. the volume of propane needed in gallons to match the wood-burning output
3. cost of heating with propane
4. amount of electricity needed in kWh
5. cost of heating with electricity