Wood heat cost comparison

Fuels sell in incompatible units — cords, tons, therms, kilowatt-hours — so the only honest comparison is dollars per million BTU of heat delivered into the room, after each appliance's efficiency. Enter your local prices; the defaults are rough national figures, and your real prices vary a lot by region.

Heat source Fuel energy Efficiency $ / MMBtu delivered
Cord wood (EPA-certified stove) 22 MMBtu/cord
Wood pellets (pellet stove) 16.4 MMBtu/ton
Natural gas (95% AFUE furnace) 0.1 MMBtu/therm 95%
Electric resistance (baseboard/space heater) 3,412 BTU/kWh 100% (COP 1)

Assumptions (read before trusting any fuel-cost table)