Heat pump vs furnace operating-cost calculator
Energy cost per year of each heating system, at your state's EIA prices.
This calculator estimates the annual energy cost of heating a home with a heat pump versus a natural-gas furnace, propane, heating oil or electric resistance. It converts your home's heat demand to BTU, then prices that heat with each system using the ENERGY STAR energy-content constants, the efficiency you choose, and your state's EIA fuel prices (prefilled, editable). It is an estimate — not a quote or an engineering load calculation.
Source: ENERGY STAR Thermal Energy Conversions. Data as of June 2026.
The energy-conversion constants used
Comparing fuels fairly means putting them all in the same useful-heat unit (BTU). These are the standard ENERGY STAR thermal conversions:
| One unit of fuel | Energy content |
|---|---|
| 1 therm of natural gas | 100,000 BTU |
| 1 kWh of electricity | 3,412 BTU |
| 1 gallon of heating oil (No. 2) | 138,500 BTU |
| 1 gallon of propane | 91,500 BTU |
Source: ENERGY STAR Thermal Energy Conversions. Data as of June 2026.
The formulas (no black box)
- Fossil fuel: annual cost = (heat demand ÷ AFUE) ÷ (BTU per unit) × price per unit.
- Heat pump: annual cost = heat demand ÷ (3,412 × seasonal COP) × electricity $/kWh.
- Electric resistance: the heat-pump formula with COP = 1.0.
The full worked method, the per-square-foot heat-demand assumptions and the climate-zone COP presets are on the methodology page.
Use it for your state
Every state page shows that state's exact fuel prices and a worked comparison; the compare-fuels hubs explain heat pump vs each individual fuel. Source for prices: EIA.
Frequently asked questions
How does the heat pump vs furnace calculator work?
It estimates your annual useful-heat demand (BTU) from your home size and climate zone, then prices that heat with each system: for fossil fuels, cost = (heat / AFUE) / (BTU per unit) x price; for a heat pump, cost = heat / (3,412 x seasonal COP) x electricity price. All prices prefill from the EIA snapshot for your state and are editable.
What is a good seasonal COP to use?
For a modern variable-speed (cold-climate) air-source heat pump, a seasonal COP of about 3.2 in mild climates, 2.8 in mixed climates, 2.4 in cold climates and 2.0 in very cold climates is a reasonable planning value. Ground-source (geothermal) systems are higher (often 3.5-4.5). Your real seasonal COP depends on the equipment and your winter.
Does this include the cost of buying and installing the system?
No. The calculator compares operating (energy) cost only. Installed cost, maintenance and available rebates (federal 25C tax credit, HOMES/HEAR, and state/utility programs) all affect the total cost of ownership but are out of scope here. See the blog for 2026 rebate context.
Why is electric-resistance heat so expensive?
Electric resistance (baseboard, electric furnace strips) converts electricity to heat at a COP of 1.0 - one unit in, one unit out. A heat pump moves 2-3 units of heat per unit of electricity, so at the same electricity price a heat pump costs roughly one-half to one-third as much to run.
Accuracy & limits
Estimate for general information, not a quote. Heat demand uses a per-square-foot planning band by climate zone — your home's insulation, air sealing, windows, thermostat habits and the actual winter change it substantially. Seasonal COP and AFUE are assumptions; fuel prices are statewide/regional EIA averages. Always confirm with an HVAC professional and your own utility bills. See the methodology and disclaimer.
Last updated: 2026-06-29