Heat Pump vs Furnace Calculator
Compare the yearly cost of heating your home with a heat pump, gas furnace, propane, oil or electric resistance – using your climate, your local fuel prices and the efficiency of each system.
Formulas shown on this page · Last reviewed October 2026
MMBtu = million BTU of heat delivered to the home. Gas, propane and oil use the AFUE above. Estimates exclude equipment, installation, fixed utility charges and incentives.
How the calculation works
heat needed (BTU) = fuel used × BTU per unit × AFUE
gas / propane / oil cost = heat needed ÷ (BTU per unit × AFUE) × price
heat pump kWh = heat needed ÷ (HSPF2 × 1,000)
seasonal COP = HSPF2 ÷ 3.412
breakeven electricity price = gas cost ÷ heat pump kWh
HSPF2 is heat delivered in BTU per watt-hour of electricity over a typical season, so dividing by 3.412 BTU per Wh gives the average coefficient of performance (COP): HSPF2 9 is a seasonal COP of about 2.6, meaning 2.6 units of heat for each unit of electricity. Electric resistance is COP 1. A furnace's AFUE is the share of fuel energy that becomes heat in the house.
Energy content used: 1 therm = 100,000 BTU, natural gas ≈ 1,037,000 BTU per Mcf (about 10.4 therms), propane 91,452 BTU/gal, heating oil 138,500 BTU/gal, electricity 3,412 BTU/kWh.
Cost per million BTU of heat at US-average prices
| System | Assumption | Price used | Cost per MMBtu delivered |
|---|---|---|---|
| Heat pump | HSPF2 9 (COP 2.6) | 18.3¢/kWh | $20.34 |
| Natural gas furnace | 95% AFUE | $1.43/therm | $15.05 |
| Natural gas furnace | 80% AFUE | $1.43/therm | $17.88 |
| Propane furnace | 95% AFUE | $2.689/gal | $30.95 |
| Oil furnace | 95% AFUE | $6.19/gal | $47.05 |
| Electric resistance | COP 1 | 18.3¢/kWh | $53.66 |
Prices as of July 2026 (electricity), the Nov 2025–Mar 2026 heating season (gas) and week of Oct 19, 2026 (propane, oil). Verified October 23, 2026.
When a heat pump wins – and when it loses
- Wins: replacing propane, oil or electric resistance; mild and marine climates; high gas prices; homes that also need air conditioning (one system does both); utilities with heat-pump or time-of-use rates.
- Loses on running cost: cheap natural gas combined with expensive electricity (at the US averages above, gas is cheaper per BTU), and very cold climates where a standard heat pump runs at a lower COP than its seasonal rating.
- Dual fuel: a heat pump paired with a gas furnace switches to gas on the coldest days. It captures most of the savings in mild weather while keeping gas as backup.
- Cold-climate heat pumps are designed to keep heating at low outdoor temperatures. HSPF2 is a seasonal average for a standard test climate, so use a conservative (lower) HSPF2 for very cold regions.
Tips before you decide
- Use last winter's therms when you have them – it is far more accurate than the climate estimate.
- Use your own electricity and gas rates, not national averages. See electricity cost by state.
- Natural gas bills include fixed monthly charges, so summer per-unit prices look inflated; use heating-season rates.
- Compare installed cost, available rebates and tax credits as well as running cost, and size the equipment properly with the BTU calculator.
- Better insulation and air sealing cut the load for either system.
How the load estimate works
The climate option uses EIA's 2020 Residential Energy Consumption Survey average natural gas space-heating use per gas-heating household (Very cold/Cold 60.75 MMBtu, Mixed-humid 44.01, Marine 30.24, Hot-humid 20.8, Mixed-dry/Hot-dry 19.01). We assume those homes' furnaces average about 85% efficiency to convert fuel to delivered heat, and the home-size multipliers (0.7×, 1×, 1.4×) are rough estimates. These are household averages, not a load calculation for your house.
Sources (checked October 23, 2026)
- EIA Electric Power Monthly, Table 5.6.A (average price of electricity, residential)
- EIA U.S. residential natural gas price ($/Mcf, monthly)
- EIA Heating Oil and Propane Update (weekly residential prices)
- EIA Units and calculators: British thermal units (BTU factors)
- EIA RECS 2020, Table CE5.4 (household natural gas and propane end-use consumption)
- ENERGY STAR: HSPF2 and SEER2 under the M1 test procedure
- ASAP: gas furnace standards (80% AFUE now; 95% AFUE final rule from December 2028)
Frequently asked questions
Is a heat pump cheaper than gas?
It depends on the price ratio. With an HSPF2 9 heat pump and a 95% AFUE gas furnace, the heat pump wins when electricity is below about 13.5¢/kWh at $1.43/therm gas. At the July 2026 US average of 18.3¢, gas is still cheaper to run: about $777 vs $1,051 a year for a typical cold-climate home (RECS 2020 average load). Against an 80% AFUE furnace the gap narrows to $923 vs $1,051.
How much does a heat pump save vs propane or oil?
A lot, because those fuels cost far more per BTU. In the same typical cold-climate home, propane at $2.689/gal costs about $1,598 a year and oil at $6.19/gal about $2,429, versus $1,051 for the heat pump – a saving of roughly $548 vs propane and $1,379 vs oil. Check current local prices, since both swing seasonally.
What is the electricity price where a heat pump equals gas?
Breakeven electricity price = gas cost per kWh of heat pump electricity. At $1.43/therm, 95% AFUE and HSPF2 9 it is about 13.5¢/kWh. If your gas costs $2.20/therm, the same home pays $1,196 for gas vs $1,051 for the heat pump, so the heat pump wins.
Does a low-efficiency heat pump still beat electric resistance?
Yes. Even a minimum-efficiency HSPF2 7.5 unit (seasonal COP about 2.2) costs about $1,261 a year in the typical cold-climate example, vs $2,771 for baseboard or electric furnace heat, which has a COP of 1. In a mild marine climate the same comparison is $523 vs $1,379.