Firewood Heating Cost Calculator
Compare the cost per kWh of heat from firewood against electricity, based on firewood price, energy content and stove efficiency.
How to use the firewood heating cost calculator
- Enter the price you pay per cord of firewood (a stacked cord, roughly 128 cubic feet).
- Enter the energy content — dry hardwood like oak or hickory typically contains around 5,500-6,500 kWh per cord, depending on species and moisture.
- Enter the stove's efficiency — modern clean-burning stoves are typically 70-80%.
- Enter the electricity price you're comparing against.
- Cost per usable kWh and the savings update automatically.
Why does stove efficiency matter so much?
Not all the energy in firewood becomes heat in the room — some is lost up the chimney. Efficiency tells you what share of the wood's energy content actually becomes useful heat. The formula is cost per kWh = firewood price ÷ (energy content × efficiency). An old open fireplace can have an efficiency below 20%, while a modern clean-burning stove typically reaches 70-80% — that makes a big difference to how cost-effective firewood heating actually is.
Frequently asked questions
What is a "cord" of firewood?
A cord is a standard unit for firewood — a stack measuring 4×4×8 feet (128 cubic feet total). Be aware that firewood is also sold in other units (face cords, by weight, by the truckload), which give a different actual amount of wood per unit.
Why does damp wood give less heat?
Damp wood uses part of the combustion energy to evaporate the water in the wood before it actually heats the room — this significantly reduces the real efficiency. Well-seasoned wood (under 20% moisture) gives noticeably more usable heat than fresh, "green" wood.
Is firewood heating always cheaper than electricity?
Not necessarily — it depends on firewood price, stove efficiency, and the electricity price where you live. This calculator lets you plug in your own numbers for a more precise comparison than a general rule of thumb.