Boston colonial, 18,000 kWh demand
Heat pump (COP 3) = 6,000 kWh × $0.27 = $1,620. 95% gas = 645 therms × $1.85 = $1,194. Gas wins on cost, heat pump wins on CO₂.
Heat pump vs gas calculator
Should I replace my gas furnace with a heat pump?
Convert your annual heating demand to kWh and therms with COP and AFUE, then compare yearly fuel cost and CO₂. Uses EPA grid average 0.39 kg CO₂/kWh and 5.3 kg CO₂/therm.
Heat Pump vs Gas
Heat pump vs gas furnace annual cost
Annual savings-$25.15
Percent saved-2.7%
Heat pump annual cost$960.00
Gas annual cost$934.85
Heat pump electric use6,000 kWh
Gas use668 therm
CO₂ — heat pump2,400 kg
CO₂ — gas furnace3,539 kg
Results are first-pass estimates. Verify with installers, manufacturers, and utility tariffs before purchase.
How it works
How it works
- Heat pump kWh = annual heating kWh ÷ COP. Cold-climate heat pumps hold COP 2.5–3.5 down to −15 °C.
- Gas therms = annual heating kWh ÷ (AFUE × 29.3 kWh/therm). 95% AFUE condensing furnaces are typical.
- Annual cost = kWh × electric rate vs therms × gas price. CO₂ = kWh × 0.39 + therms × 5.3.
Worked examples
Worked examples
Atlanta, 9,000 kWh demand
Heat pump (COP 3.5) = 2,570 kWh × $0.13 = $334. Gas 95% = 323 therms × $1.55 = $501. Heat pump wins both.
Seattle (hydro grid), 12,000 kWh demand
Grid 0.10 kg CO₂/kWh. Heat pump emits 400 kg, gas emits 2,280 kg — 5.7× advantage.
Heat pump FAQ
Heat pump FAQ
How do I find my annual heating demand?
Multiply annual gas therms × AFUE × 29.3 to get kWh delivered. Or use Manual J load × heating degree days.
What COP should I use?
Use HSPF2 from the AHRI label, divide by 3.412 for seasonal COP. Modern cold-climate units: 2.5–3.0 in Zone 5; 3.5–4.5 in Zone 3.
Does the calculator include backup heat?
No — assumes the heat pump meets the full load. Add 1,500–3,000 kWh of resistance backup for sub-zero days.
Are CO₂ factors current?
EPA eGRID 2022 US average is 0.39 kg/kWh. Use NREL Cambium for state-specific values; many regions are 0.15–0.25 now.
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