Heat Pump vs Gas Furnace Bill Crossover Calculator

See whether a cold-climate heat pump beats your gas furnace on energy bills and emissions. Provide your seasonal heating load, heat pump COP, and current energy rates to compare annual energy spend, tons of CO₂ emitted, and the natural gas price that would make both systems cost the same.

Total heat you need to deliver over the heating season expressed as kWh.
Average coefficient of performance for the heat pump across the season.
Blended energy supply and delivery charge per kWh.
Delivered cost per therm on your utility bill.
Defaults to 92%. Represents AFUE or seasonal efficiency for the gas furnace.
Defaults to 0.92 lbs CO₂ per kWh.
Defaults to 11.70 lbs CO₂ per therm.

Outputs assume steady COP and efficiency. Real-world performance varies with outdoor temperature and thermostat settings.

Examples

  • 12,000 kWh load, 3.2 COP, $0.18/kWh electricity, $1.80/therm gas, 92% furnace ⇒ Heat pump energy: 3,750.00 kWh costing $675.00 • Gas furnace energy: 445.11 therms costing $801.19 • Annual bill difference: $126.19 (savings with heat pump) • Gas price breakeven: $2.18 per therm • Emissions impact: -0.86 metric tons CO₂e vs. gas • Recommendation: Heat pump is cheaper this season.
  • 18,000 kWh load, 2.8 COP, $0.24/kWh electricity, $1.20/therm gas, 95% furnace ⇒ Heat pump energy: 6,428.57 kWh costing $1,542.86 • Gas furnace energy: 640.68 therms costing $768.82 • Annual bill difference: -$774.04 (more expensive than gas) • Gas price breakeven: $2.28 per therm • Emissions impact: +0.15 metric tons CO₂e vs. gas • Recommendation: Gas furnace remains cheaper at current rates.
  • 9,500 kWh load, 3.6 COP, $0.17/kWh electricity, $2.20/therm gas, 90% furnace ⇒ Heat pump energy: 2,638.89 kWh costing $448.61 • Gas furnace energy: 362.27 therms costing $796.99 • Annual bill difference: $348.38 (savings with heat pump) • Gas price breakeven: $2.03 per therm • Emissions impact: -0.72 metric tons CO₂e vs. gas • Recommendation: Heat pump is cheaper this season.

FAQ

How do I estimate my seasonal heating load?

Add up heating energy from past utility bills or multiply your design heat loss by heating degree days. Many homeowners use Manual J reports or smart thermostat analytics for accuracy.

Can I include maintenance costs?

Add recurring maintenance differences to the savings result manually, or adjust your energy rates to reflect service plans and filter replacements.

What if I run a dual-fuel system?

Estimate the share of the load each system handles and run the calculator twice, weighting the savings by each share.

How do carbon prices or renewable energy credits factor in?

Enter higher emission factors or add the implied cost of carbon to your electricity or gas rates. That lets the savings output reflect policy incentives tied to avoided emissions.

What if my utility has time-of-use electric rates?

Use a blended average rate that reflects your winter usage profile or rerun the calculator with separate peak and off-peak assumptions to bracket the seasonal cost impact.

Additional Information

  • Heating load is the amount of heat you must deliver to your home over the entire season.
  • Gas furnace therm usage divides load by efficiency and converts from kWh to therms (1 therm ≈ 29.3 kWh).
  • Breakeven gas price multiplies your electricity rate by the heat pump's efficiency advantage after accounting for furnace AFUE.
  • Emission factors can be customized to reflect your utility mix, renewable energy certificates, or regional carbon accounting.
  • Cost difference is expressed as gas minus heat pump so positive values indicate savings when switching to the heat pump.
  • Adjust the optional efficiency and emission inputs to reflect dual-fuel setups, green tariffs, or premium furnaces.

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