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Heating fuel cost comparison ($/MMBtu)
Delivered-heat cost per million Btu, ranked across fuels.
Heat content per unit, from the EIA energy conversion tables: propane 91,452 Btu/gal, No. 2 heating oil 138,500 Btu/gal, natural gas 100,000 Btu/therm, electricity 3,412 Btu/kWh. Efficiency is the share of that heat delivered to the room; the defaults (90% propane, 85% oil, 92% gas, 100% electric resistance) are typical mid-range appliance figures, editable above — a heat pump delivers 200-300% and is entered as such. The result is a per-MMBtu cost of delivered heat; local prices, taxes, and equipment vary. How a heat pump's efficiency shifts with outdoor temperature, and the break-even it has to beat against propane, is worked through in Propane vs heat pump: which costs less to run?
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Worked example at the prefilled prices
The calculator loads with the prices below. Each one is turned into the cost of a million Btu of heat delivered to the house: price, divided by the fuel's heat content, times one million, divided by the appliance efficiency.
| Fuel | Prefilled price | Heat per unit | Efficiency | Per million Btu delivered |
|---|---|---|---|---|
| Propane | $2.730/gal | 91,452 Btu/gal | 90% | $33.17 |
| Heating oil | $6.233/gal | 138,500 Btu/gal | 85% | $52.95 |
| Natural gas | $1.347/therm | 100,000 Btu/therm | 92% | $14.64 |
| Electricity (resistance) | $0.1745/kWh | 3,412 Btu/kWh | 100% | $51.14 |
For propane at the US average in EIA's Oct 26, 2026 survey: $2.730 ÷ 91,452 Btu × 1,000,000 = $29.85 per million Btu in the fuel itself, and at 90% furnace efficiency $33.17 delivered. A heat pump enters the electricity line at its seasonal efficiency instead of 100%: at 250% the same electricity price delivers heat at $20.46 per million Btu.
Where the prefilled prices come from
Propane and heating oil are EIA's US residential averages from the same week of its heating-season survey (the State Heating Oil and Propane Program, weekly October through March), read off the US propane price page. Dealers quote above or below the average: the state price pages carry each surveyed state's figure.
Natural gas and electricity are monthly utility averages, so they default to January 2026, a heating month. The month matters for gas: the fixed part of a gas bill is spread over far less gas in summer, and EIA's US residential gas price was $26.45 per thousand cubic feet in July 2026 against $13.96 in January. The therm figure converts January's price at EIA's average heat content of 1,036 Btu per cubic foot: $13.96 ÷ 10.36 therms = $1.347 a therm. Electricity is EIA's US residential average for January 2026, 17.45 cents a kWh. Your own bill's price per therm or kWh, all charges included, is the better input.
What the comparison leaves out
The result is the running cost of heat only. It leaves out equipment and installation, maintenance, tank rental or delivery fees, and the fixed monthly charge on a gas or electric bill. A heat pump's efficiency also falls as the outdoor temperature drops, which Propane vs heat pump: which costs less to run? works through with a break-even formula.
Common questions
Is propane or heating oil cheaper per Btu?
It depends on the local price of each and your appliance efficiencies. This tool converts both to dollars per million Btu of delivered heat so they compare on the same basis — enter your prices above.
How do you compare propane, gas, oil, and electricity?
Convert each fuel's price to the cost of a million Btu using its heat content, then divide by the appliance's efficiency to get the cost of delivered heat. The lowest dollars-per-MMBtu is the cheapest heat.