Estimate only. Real costs depend on your climate, your home's insulation and your exact utility rates.
How the comparison works
- Heat you use today: the gas you burn for heating (in therms, from your bills) × 100,000 Btu per therm × your furnace efficiency (AFUE).
- Electricity a heat pump would need: that same heat ÷ (HSPF2 × 1,000). HSPF2 is the heat pump's seasonal heating efficiency in Btu per watt-hour.
- Costs: gas at your state's average residential price and electricity at your state's average residential price.
A negative result means the heat pump would cost more to run than your furnace.
Why the answer changes by state
A heat pump wins where electricity is cheap compared to gas. In states with expensive electricity and moderate gas prices, a minimum-efficiency heat pump can cost more to run than a gas furnace; a high-efficiency model (higher HSPF2) narrows or reverses that gap. Cooling is not included: if you would buy a new air conditioner anyway, a heat pump also does that job.
Data used
- Gas prices: EIA, residential natural gas price by state, 2025 annual average (2024 where 2025 is not yet published), converted at 10.37 therms per Mcf (EIA).
- Electricity prices: EIA Electric Power Monthly, Table 5.6.B.
- The default HSPF2 of 7.5 is the federal minimum for split-system heat pumps made since January 1, 2023 (10 CFR 430.32). HSPF2 is measured for a reference climate; in very cold regions real efficiency is lower.
Example: 600 therms a year
A home that burns 600 therms of gas a year in an 80% furnace gets about 48 million Btu of heat. A heat pump with the federal minimum HSPF2 of 7.5 needs about 6,400 kWh to deliver the same heat; one with an HSPF2 of 9 needs about 5,330 kWh. Whether that costs less than gas depends on your state's prices, as the table below shows for six states.
How to find your therms
Add up the therms on your last 12 gas bills. If your gas also heats water, cooks or dries clothes, subtract an estimate for those uses: in summer months, when the furnace is off, your gas use is mostly those other loads. Multiply a typical summer month by 12 and subtract it from the yearly total.
How to read your result
- Gas heating cost uses your state's average residential gas price and the EIA's conversion of 10.37 therms per thousand cubic feet.
- Heat pump electricity is the heat your furnace delivers divided by the heat pump's seasonal efficiency (HSPF2).
- Savings can be negative: where electricity is expensive and gas is cheap, a heat pump can cost more to run.
What the comparison does not include
- Cold climates. HSPF2 is a seasonal average for a reference climate; in very cold weather, efficiency drops and backup heat may run.
- Cooling. A heat pump also replaces your air conditioner; if your AC is old, the new unit's cooling efficiency adds savings.
- Fixed gas charges. If you remove gas entirely, you also stop paying the gas utility's monthly fixed charge.
- Installation cost, rebates and any electrical upgrades.