How to use this calculator
Fuel prices alone cannot compare heating systems. A heat pump moves multiple units of heat per unit of electricity, while a furnace loses part of its fuel energy through combustion and venting.
- Estimate annual delivered heating need.
- Use a seasonal COP, not a mild-weather rating.
- Enter marginal electricity and gas prices.
FORMULA
The math behind the estimate
Heat pump kWh = heat need × 293.071 ÷ COP. Gas therms = heat need × 10 ÷ furnace efficiency.
Worked example
For 50 MMBtu, COP 3, $0.18/kWh, 95% gas efficiency, and $1.60/therm, the heat pump costs about $879 versus $842 for gas.
Change the defaults to model your home. The result is an estimate, not a guaranteed bill or savings promise.
How to read the result
Use the estimate to compare scenarios and find the inputs worth measuring more carefully. Utility bills can include fixed charges, taxes, delivery fees, minimums, tiers, and demand charges that are not fully represented by a simple energy rate.
Assumptions and limitations
- The load is delivered heat, not fuel input.
- COP and efficiency are seasonal averages.
- Installation, service charges, and backup heat are excluded.
Climate, equipment condition, installation, controls, and household behavior can materially change results. Verify consequential installation and purchasing decisions with qualified providers.
Practical savings context
Run low, expected, and cold-climate COP scenarios. Have qualified contractors verify sizing, ductwork, electrical capacity, and installed cost.
SOURCE
Data and methodology
U.S. Department of Energy — Heat Pump Systems
Guidance accessed August 2026. Geographic scope: United States. Last reviewed: August 6, 2026.
WattMeasure uses the source to frame the method and assumptions; your editable inputs determine the displayed result.
QUESTIONS
Heat pump vs gas FAQ
How accurate is this heating comparison estimate?
It is a planning estimate based on the values you enter. Actual power draw, cycling, utility charges, climate, and equipment condition can change the result.
Should I use the default electricity rate?
Your own marginal or all-in supply rate is better. Check a recent bill or your utility's published rate schedule.
Does this include taxes and utility fees?
Only when they are reflected in the rate you enter. Fixed monthly charges are not included because they usually do not change with one appliance's usage.
Last reviewed August 6, 2026 · Data update policy