Heating Fuel Cost Comparison Calculator

Put gas, propane, oil, electricity, a heat pump, wood and pellets on the same footing — cost per useful MMBtu and annual cost, ranked, with every efficiency shown and yours to edit.

Most heating cost comparisons hide the efficiency they assumed, and many are run by a company that sells one fuel. This one shows every assumption, lets you change all of them, enters no prices for you that you can’t overwrite, and never favours a fuel — the ranking is just your numbers.

Pick the fuels and enter your local price & efficiency
FuelPrice / unit ($)Eff. or COP

Prices shown are editable examples only — replace them with your own. Efficiency is AFUE for a furnace, appliance efficiency for a stove, or COP (a number above 1) for a heat pump.

Don't know it? Estimate whole-home loss with the heat loss calculator over the heating season.

A neutral planning aid using public-domain fuel energy values. Real bills also depend on equipment age, climate, distribution losses, standing charges and how a heat pump’s COP falls in the cold. No prices are fetched or stored. Not affiliated with any utility or fuel dealer.

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Sizing the demand or weighing wood? Get the annual heat demand this calculator needs from the heat loss calculator (whole house) or the BTU calculator (per room). Leaning toward wood? The firewood calculator & BTU chart works out cords and heat output by species.

How to compare heating costs fairly

Comparing raw fuel prices is meaningless because each unit carries a different amount of energy and each appliance wastes a different share of it. The fair measure is the cost of a million BTU of heat that actually reaches the room — cost per useful MMBtu — which folds price, energy content and efficiency into one number you can rank.

cost per useful MMBtu = price per unit ÷ (BTU per unit × efficiency) × 1,000,000 annual cost = heat demand (MMBtu) × cost per useful MMBtu

Efficiency is the AFUE for a furnace or boiler, the appliance efficiency for a stove, and the COP for a heat pump. A heat pump’s COP is greater than one — it moves several units of heat per unit of electricity rather than making heat — which is why electricity through a heat pump can beat electricity through a baseboard several times over at the same price per kWh.

Is propane heat cheaper than electric?

This is the most-asked pairing, and the honest answer is “it depends, here is the math.” Against electric resistance heat, propane often wins, because resistance heat costs the electricity price divided by 3,412 BTU per kWh with no efficiency multiplier to help it. Against an air-source heat pump it is usually the other way around: the heat pump’s COP divides the effective electricity price by two to four, so the cost of propane heat per useful MMBtu typically sits above the heat pump. Put your real propane-per-gallon and electric-per-kWh figures in and the ranking settles it for your prices, not a generic claim.

Is propane cheaper than natural gas?

Where natural gas is available it almost always costs less per unit of heat. A therm of gas is 100,000 BTU and is priced low; propane holds about 91,500 BTU per gallon but usually costs enough per gallon that its cost per useful MMBtu lands above gas. The break-even tool shows the precise propane price at which the two tie for your gas price — useful when a propane supplier quotes a seasonal rate.

Heat pump vs gas furnace running cost

The heat-pump-vs-furnace mode pits a heat pump’s seasonal COP (or its HSPF, divided by 3.412 to get COP) against a furnace’s AFUE at your electricity and fuel prices. A heat pump near COP 3 competes with cheap natural gas and beats propane, oil and resistance heat comfortably. The important caveat the mode keeps in view: COP drops as the outdoor temperature falls, so the seasonal average is below the rated number, and in very cold climates a backup fuel changes the picture.

BTU per unit reference

These are the public-domain energy contents the calculator uses. They are the gross heat content per unit before any appliance efficiency — the efficiency is applied separately so you can adjust it. Note the answer to a common search: there are about 138,500 BTU per gallon of #2 heating (fuel) oil.

Approximate energy content per unit of common heating fuels (gross, before efficiency).
FuelUnitBTU per unitPer MMBtu

A handy cross-check: one million BTU is roughly 7 gallons of heating oil, 293 kWh of electricity, 976 cubic feet of natural gas, 11 gallons of propane, 125 lb of seasoned wood or 71 lb of coal — before efficiency.

Electric vs gas for a water heater

The same cost-per-useful-MMBtu method answers the water-heater version of the question. A gas tank burns cheap fuel but vents heat up the flue, lowering its efficiency; an electric resistance tank is near 100% efficient at the tank but pays more per raw BTU; a heat-pump water heater multiplies its electricity by a COP and is usually cheapest to run where it fits. Enter your gas and electricity prices in the compare tab and read electric resistance, heat pump and gas side by side.

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Frequently asked questions

Why do fuel cost comparisons give different answers?

Two reasons. Most bury an efficiency assumption — a 95% furnace, a heat pump at COP 3, an 80% stove — and a small change there swings the result, yet few show the number used. And many tools are run by a dealer who sells one fuel, so the assumptions quietly favour it. This one shows every efficiency, lets you edit all of them, and ranks with no thumb on the scale.

Is propane cheaper than electric heat?

It depends on your prices and which electric heat. Against electric resistance, propane often wins (resistance has no efficiency multiplier). Against a heat pump, propane usually loses, because the heat pump’s COP cuts the effective electricity price two- to four-fold. Enter your propane-per-gallon and electric-per-kWh figures above to see the cost per useful MMBtu for each.

Is propane cheaper than natural gas?

Natural gas is almost always cheaper per unit of heat — a therm is 100,000 BTU and priced low. Propane holds about 91,500 BTU per gallon but usually costs enough per gallon to land above gas in cost per useful MMBtu. The break-even tool shows the propane price at which they tie for your gas price.

Is a heat pump cheaper to run than a gas furnace?

Often, but it hinges on the heat pump’s seasonal COP and your local prices. A heat pump near COP 3 competes with cheap gas and beats propane, oil and resistance heat. The catch: COP falls as it gets colder, so the seasonal average is below the rated figure. The heat-pump-vs-furnace mode shows the crossover at your prices.

How do you calculate cost per useful MMBtu?

Price per unit ÷ (BTU per unit × efficiency) × 1,000,000. Efficiency is AFUE for a furnace, COP for a heat pump (above 1), or appliance efficiency for a stove. This puts every fuel on the same footing — useful heat in the room — rather than comparing raw fuel prices that hide how much heat each unit delivers.

Is electric or gas cheaper for a water heater?

Same logic. A gas tank burns cheap fuel but loses heat up the flue; an electric resistance tank is near 100% efficient but costs more per raw BTU; a heat-pump water heater multiplies electricity by a COP and is usually cheapest where it fits. Compare electric resistance, heat pump and gas in the compare tab using your rates.