Reference
Fuel Energy Content and Cost per Million BTU
The energy in each heating fuel, the prices and efficiencies the calculators start from, and what a million BTU of delivered heat costs with each.
Energy content
| Fuel | Unit | BTU per unit | Source |
|---|---|---|---|
| Natural gas | therm | 100,000 | EIA (definition) |
| Natural gas | CCF (100 cubic feet) | 103,700 | EIA, 2024 average heat content delivered to consumers |
| Natural gas | MCF (1,000 cubic feet) | 1,037,000 | EIA, same basis |
| Propane | gallon | 91,452 | EIA |
| Heating oil, No. 2 | gallon | 138,500 | EIA |
| Kerosene | gallon | 135,000 | EIA |
| Electricity | kWh | 3,412 | EIA (exact conversion 3,412.14) |
| Wood pellets | ton | 16.5 million | EIA |
| Cordwood, air-dried hardwood | cord | 20 million | EIA (15 to 30 million by species and moisture) |
Default prices, efficiencies and cost per million BTU
| Fuel | Default price | Default efficiency | Cost per million BTU delivered |
|---|---|---|---|
| Natural gas | $1.50 per therm | 95% AFUE | $15.79 |
| Heat pump | $0.17 per kWh | seasonal COP 2.8 | $17.79 |
| Cordwood | $300 per cord | 70% | $21.43 |
| Wood pellets | $300 per ton | 80% | $22.73 |
| Propane | $2.70 per gallon | 95% AFUE | $31.08 |
| Heating oil | $3.70 per gallon | 85% AFUE | $31.43 |
| Electric resistance | $0.17 per kWh | 100% | $49.82 |
Default prices are rounded US residential averages from EIA data for 2025. Local prices differ widely, by state and by season, so replace them with the figures on your bills. Kerosene defaults to $4.20 per gallon where a calculator offers it.
At the defaults the break-even electricity price for a heat pump against gas is 15.1 cents per kWh: below it, the heat pump is cheaper per BTU.
Season heating cost for one house
A zone 5 house with a 60,000 BTU/hr design load needs about 84.2 million BTU of heat a season, from the degree-day method (60,000 ÷ 70 × 24 × 6,300 × 0.65). At the defaults:
| Fuel | Season cost | Quantity |
|---|---|---|
| Natural gas | $1,330 | 887 therms |
| Heat pump | $1,499 | 8,817 kWh |
| Cordwood | $1,805 | |
| Wood pellets | $1,915 | |
| Propane | $2,618 | 970 gallons |
| Heating oil | $2,648 | 716 gallons |
| Electric resistance | $4,197 | 24,688 kWh |
Water
Heating one US gallon of water by 1 °F takes 8.34 BTU. Daily water heating energy is gallons × 8.34 × temperature rise ÷ UEF.
Calculators that use these figures
- Costs: cost per million BTU, HVAC running cost, heat pump vs furnace, degree-day fuel estimate, setback savings
- Heating: heating cost by fuel, BTU to watts converter
- Water heating: water heater running cost, hot water use
The guide to comparing fuels per million BTU explains the method.