Understanding your result
The headline is the cheapest fuel and its cost per million BTU delivered, with the dearest in the sub-line. The bars rank all seven fuels. The table lists them cheapest first with each one’s price, energy content, efficiency and its multiple of the cheapest, then two equivalents for the cheapest fuel: its cost per therm of delivered heat and per kWh of delivered heat, which are handy for comparing with a quote priced either way.
The notes give the heat pump’s break-even electricity price against gas at your gas price and efficiencies, the single number that settles most heat pump questions before any house-specific arithmetic.
To turn these figures into a season’s bill, multiply by the house’s heat, which the heating cost by fuel calculator and the degree-day fuel estimate work out. For a closer look at the two front-runners, with backup heat and a season’s figures, use the heat pump versus gas furnace calculator; for the hourly cost of a particular system, the HVAC running cost calculator.
How we calculate this
The energy contents are the US Energy Information Administration’s: 100,000 BTU per therm, about 103,700 per CCF of gas delivered to consumers (2024 average), 91,452 per gallon of propane, 138,500 per gallon of No. 2 heating oil, 3,412 per kWh, about 16.5 million per ton of wood pellets and about 20 million per cord of air-dried hardwood. The default prices are EIA residential averages for 2025 and the 2024–25 heating season, and typical delivered prices for pellets and wood. They are all set out, with their sources and ranges, on the fuel energy content and cost page, and the efficiencies on the efficiency ratings table.
The assumptions behind the numbers
| Fuel | Default price and efficiency | Energy content (EIA) |
|---|---|---|
| Natural gas | $1.50 per therm, 95% AFUE | 100,000 BTU per therm; about 103,700 per CCF |
| Propane | $2.70 per gallon, 95% AFUE | 91,452 BTU per gallon |
| Heating oil | $3.70 per gallon, 85% AFUE | 138,500 BTU per gallon |
| Heat pump | $0.17 per kWh, COP 2.8 | 3,412 BTU per kWh |
| Electric resistance | $0.17 per kWh, 100% | 3,412 BTU per kWh |
| Wood pellets | $300 per ton, 80% | about 16.5 million BTU per ton |
| Cordwood | $300 per cord, 70% | about 20 million BTU per cord (15 to 30 by species) |
Assumptions last reviewed October 8, 2026.
The ranking uses each fuel’s seasonal efficiency and does not include equipment, installation, maintenance, the fixed monthly charge on a gas account, the labour of wood heat, or a heat pump’s lower COP in very cold weather. The guide to comparing fuels per million BTU covers those, and the guide to heat pumps in cold climates explains why a heat pump’s winter COP is lower than its seasonal rating.
Two worked examples
National average prices
All defaults: gas $1.50 per therm at 95%, heat pump at COP 2.8 and propane, oil, electricity, pellets and wood at their defaults.
- Gas: $1.50 ÷ 100,000 × 1,000,000 ÷ 0.95 = $15.79
- Heat pump: $0.17 ÷ 3,412 × 1,000,000 ÷ 2.8 = $17.79 (1.13 × gas)
- Cordwood $21.43; pellets $22.73; propane $31.08; oil $31.43
- Electric resistance: $49.82 (3.16 × gas)
Gas and the heat pump are close; the break-even electricity price is 15.1 cents per kWh, so a household paying less than that for power heats more cheaply with a heat pump. Propane and oil cost twice as much per BTU as either.
Gas billed per CCF and cheap hydro power
Gas at $1.40 per CCF at 95%, electricity at $0.12 per kWh, heat pump at COP 3.2, other defaults.
- Heat pump: $0.12 ÷ 3,412 × 1,000,000 ÷ 3.2 = $10.99
- Gas: $1.40 ÷ 103,700 × 1,000,000 ÷ 0.95 = $14.21 (1.29 × the heat pump)
- Electric resistance: $35.17 (3.2 × the heat pump)
With cheap electricity and a good heat pump, the heat pump is the cheapest heat by almost a third, and even resistance heat beats propane and oil. Note that 1 CCF at 103,700 BTU holds 3.7% more than a therm, which matters when comparing a CCF price with a therm price.
Where to find your inputs
Prices. The all-in price per unit from bills or delivery tickets: total charges divided by therms, CCF, gallons or kWh. For wood and pellets, the delivered price.
Gas billing unit. On the gas bill: therms, CCF or MCF; a therm factor printed on the bill converts CCF exactly.
Efficiencies. AFUE from the furnace or boiler label; the heat pump’s HSPF2 ÷ 3.412 × 100; the stove’s EPA-certified efficiency.
Common mistakes
- Comparing prices per unit. A gallon of oil holds 1.5 times the heat of a gallon of propane.
- Ignoring efficiency. An 80% furnace burns a fifth more fuel than a 96% one for the same heat.
- Using the energy-only rate. Delivery and fixed charges are part of what a unit costs.
- Treating free wood as free heat. An open fireplace can lose more heat up the chimney than it gives.
- Using a heat pump’s rated COP in a cold climate. The seasonal figure is lower; strips lower it further.
- Mixing CCF and therms. They differ by about 4%.
Questions people ask
- What does cost per million BTU mean?
- The price of one million BTU of heat delivered into the house, after the equipment's losses. It is the fuel price divided by the fuel's energy content, scaled to a million BTU, and divided by the efficiency. Gas at $1.50 per therm in a 95% furnace is $1.50 ÷ 100,000 × 1,000,000 ÷ 0.95 = $15.79. A typical house in a cool climate needs 60 to 100 million BTU a winter, so the figure times that gives the season's bill.
- What is the cheapest way to heat a home per BTU?
- At 2025 US average prices, natural gas in a condensing furnace at about $15.79 per million BTU, then an air-source heat pump at COP 2.8 at $17.79, then cordwood at about $21 and pellets about $23 when bought, then propane and oil at about $31, and electric resistance at about $50. Regional prices change the order. In the Pacific Northwest and the South, where power is cheap, the heat pump is usually first.
- How do I convert a gas bill in CCF to therms?
- A CCF is 100 cubic feet of gas, which in 2024 held on average about 103,700 BTU according to the EIA, so 1 CCF is about 1.037 therms. An MCF is ten times that. Utilities that bill in CCF often print a therm factor on the bill; using it is more accurate than the national average. The calculator converts automatically when you choose the billing unit.
- How much heat is in a cord of wood?
- Roughly 15 to 30 million BTU depending on the species and dryness, with dense, seasoned hardwoods such as oak and hickory at the top and softwoods such as pine at the bottom. The calculator uses 20 million, a mid-range air-dried hardwood. A modern EPA-certified stove burns at 60 to 75% efficiency; an open fireplace at 10 to 30%, which makes it the most expensive heat in the house even with free wood.
- Why does a heat pump have an efficiency over 100%?
- Because it moves heat from outdoors rather than making it, delivering two to four units of heat for each unit of electricity. Its seasonal coefficient of performance, entered here as a percentage (280% for a COP of 2.8), is HSPF2 divided by 3.412 for air-source units on the label. The same electricity in a resistance heater delivers exactly one unit, which is why heat pump heat costs about a third as much.
- Does the ranking change with the house?
- No. Cost per million BTU depends only on prices and efficiencies, so the ranking is the same for every house that pays the same prices. What changes with the house is the number of million BTU, and therefore the size of the gaps in dollars. A small, tight house may save $200 a year by switching fuels; a large drafty one $2,000 at the same per-BTU prices.