Is Firewood Cheaper Than Propane? Cost per Million BTU
At the example prices below, firewood delivers heat for about half the cost of propane: roughly $18 versus $36 per million BTU. At those propane and efficiency assumptions, wood stays cheaper until a cord passes about $500. Replace the example prices with your local ones.
The formula
| Fuel | Example price | BTU per unit | Efficiency | $ per MMBtu |
|---|---|---|---|---|
| Firewood | $250/cord | 20,000,000 | 70% | $17.86 |
| Propane | $2.78/gal | 91,452 | 85% | $35.76 |
| Heating oil | $3.68/gal | 138,500 | 85% | $31.26 |
BTU values are the EIA’s averages; efficiencies are typical estimates for an EPA-certified stove and a standard furnace. Prices are examples, not current quotes.
Break-even price
Wood matches propane at about $500 per cord and matches heating oil at about $438 per cord under these assumptions. One cord delivers about as much useful heat as 180 gallons of propane.
What the math leaves out
Labor, a chainsaw or splitter, storage space, ash cleanup and the cost of the stove are not in the price per MMBtu. A wood stove also tends to heat one area better than a whole house, so you may keep burning propane or oil as backup.
How the answer changes with price
Firewood at 70% efficiency (20 million BTU per cord):
| Price per cord | $150 | $250 | $350 | $500 |
|---|---|---|---|---|
| $ per MMBtu delivered | 10.71 | 17.86 | 25.00 | 35.71 |
Propane at 85% efficiency:
| Price per gallon | $2.00 | $2.78 | $3.50 | $4.00 |
|---|---|---|---|---|
| $ per MMBtu delivered | 25.73 | 35.76 | 45.03 | 51.46 |
Efficiency also moves the numbers. The $250 cord costs $20.83 per MMBtu in a 60%-efficient stove and $15.63 at 80%. A 95%-efficient condensing propane furnace brings $2.78 propane down to $32.00.
What it means for a season
For a home that needs 50 MMBtu of delivered heat in a season, the example prices give about $893 for firewood, $1,563 for heating oil and $1,788 for propane. The difference of roughly $900 against propane has to cover your time, equipment and storage.
Costs the math leaves out
- Equipment: chainsaw, splitter, axe and a moisture meter if you process your own wood.
- Chimney and stove maintenance, which wood burning needs regularly.
- Space and time to stack and season the wood.
- Installation, local codes and your insurer’s requirements for a wood stove.
When propane or oil still makes sense
If you cannot buy seasoned wood below roughly the break-even price, if you cannot store it, or if you need automatic whole-house heat while you are away, a mix often works: wood in the main living area and propane or oil as backup. Enter your own prices in the fuel cost calculator before deciding, and see how much propane a house uses.
Sources
BTU values: U.S. Energy Information Administration. Tool for comparing fuels: Penn State Extension.
FAQ
How many gallons of propane equal a cord of wood?
About 180 gallons of useful heat, assuming 20 million BTU per cord at 70% efficiency and 91,452 BTU per gallon at 85%.
Is firewood cheaper than heating oil?
At these example prices yes, until a cord costs about $438.
Does wet wood change the cost?
Yes. Wet wood gives less usable heat per cord, which raises your real cost per MMBtu.