Homeowner Cost Lab
Heating system cost comparison

Heat pump or gas furnace: compare the costs for your home

Use the same annual heating demand for both options, then add your utility rates, equipment efficiencies, maintenance, and installed quotes. The result is only as useful as the numbers you enter.

Your comparison

Use figures from your bills, equipment labels, energy assessment, and written quotes.

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Use an energy assessment or a heating-only estimate where possible. The bill method needs only natural gas used for space heating, not water heating or cooking.
Use the same annual heat demand for both options. If your source reports another unit, convert it before entering a value.
Use the variable energy charge from your bill; do not mix monthly fixed charges into a per-kWh rate.
Use the price basis shown on your bill. Gas heat content and bill units can vary by utility.
Use an estimate for the whole heating season, not the rating at one outdoor temperature.
Cold weather, controls, installation, and backup heat affect actual performance.
Use the rating for the gas furnace in the quote you are comparing.
The calculation holds annual energy prices and maintenance constant across this period.
Use the quoted total for a comparable scope. Enter 0 if you only want to compare annual running costs.
Compare equivalent work, including required venting, electrical, duct, or disposal items where applicable.
Use a documented plan or your own estimate, not a national average.
Use the same basis as the heat-pump maintenance estimate.
Only count an avoided gas-account fee when every gas appliance is removed and the utility confirms the account can be closed.
Use the fixed monthly charge from your bill, not the gas usage charge. If service stays connected, the calculator counts this as a shared cost.

Energy formulas
Heat-pump kWh = useful heat (MMBtu) × 1,000,000 ÷ 3,412 ÷ seasonal COP
Furnace therms = useful heat (MMBtu) × 1,000,000 ÷ 100,000 ÷ AFUE
AFUE is entered as a percentage. HSPF2 is converted to a seasonal COP using the EIA's rounded 3,412 Btu per kWh factor.

What this comparison tells you

The calculator estimates how much electricity a heat pump or natural gas a furnace would use to provide the same annual amount of useful heat. It then applies your utility prices, maintenance estimates, installed quotes, and chosen time period. The result can change when any of those inputs change.

There is no universal winner. Electricity and gas prices vary by utility, and equipment ratings do not predict exactly how a system will perform in your home. The comparison is a first screen for checking quotes and operating costs, not a substitute for a load calculation or an HVAC assessment.

Where to find the inputs

  • Electricity price: use the variable energy charge on your electric bill in USD per kWh. If your rate changes by time of day or season, one average rate simplifies those differences.
  • Gas price: use the natural-gas charge on your bill in USD per therm. If your bill uses cubic feet, CCF, or another unit, convert to the same price basis before entering it; gas heat content can vary.
  • Heat-pump rating: enter a seasonal COP if you have a credible estimate. If the EnergyGuide label lists HSPF2, choose that rating basis; the calculator converts HSPF2 to a seasonal COP using the EIA's rounded Btu-per-kWh conversion.
  • Furnace AFUE: use the rating for the specific furnace option in the written quote. If you estimate heating demand from gas bills, enter the existing furnace's AFUE separately.
  • Installed price: compare quotes with similar equipment, electrical work, venting, duct changes, permits, disposal, and other scope. If an item is excluded or unclear, ask the contractor before comparing totals.

If your bill shows heating gas use, not useful heat

Select the gas-bill entry method and enter only therms used for space heating, plus the existing furnace's AFUE. The calculator estimates useful heat as heating therms × 100,000 Btu per therm × AFUE. A whole-house gas bill may also include a water heater, stove, dryer, or fireplace. If those uses cannot be separated, the estimate is uncertain; use an energy audit or a documented heating-load estimate instead.

AFUE describes fuel-to-heat efficiency at the furnace. This simplified comparison does not measure duct losses, room-by-room delivery, or how occupants use the system. The replacement furnace's AFUE is a separate input because it may differ from the existing unit.

How gas service charges are handled

If you keep gas for a water heater, cooking, or another appliance, the monthly account charge usually continues under the heat-pump option. The calculator treats it as a shared cost. It counts that charge only on the furnace side if you select that the gas account can be closed and enter no other gas use. Check your actual utility bill and service rules before treating a fixed fee as avoidable.

Limits to keep in mind

HSPF2 and seasonal COP simplify performance across weather and operating conditions. This tool does not model hourly temperatures, dual-fuel changeover, backup resistance heat as a separate load, a time-of-use tariff, price increases, financing, tax credits, equipment degradation, or discounted cash flow. Maintenance, installation, and utility prices stay constant for the comparison period.

Ask a qualified contractor to assess heating load, system sizing, electrical capacity, ductwork, ventilation, local code, and installation scope. The tool does not recommend equipment or decide whether an installation will qualify for an incentive.

Sources and method

The energy conversions follow the U.S. Energy Information Administration's energy units reference: 1 kWh is listed as 3,412 Btu and 1 therm as 100,000 Btu. The Department of Energy identifies HSPF2 in Btu per watt-hour in its air-source heat-pump purchasing guidance. Those standardized values are not a prediction of your home's seasonal bills. Sources checked October 2, 2026. See the site's calculation method and disclaimer.

For a general comparison of two installed options that already have annual running-cost estimates, use the repair-or-replace calculator. For other project quotes, see the contractor quote comparison tool.