Heat Pump Savings Calculator
A heat pump moves heat instead of creating it directly. Enter your own annual heat demand, fuel price, electricity price and realistic seasonal COP to compare running costs on equal useful heat.
Quick answerWith the default inputs, the current system costs about $988 per year and the heat pump costs about $638, for an estimated $351 annual saving. The break-even COP is about 2.06: below that, the heat pump costs more to run at these rates; above it, it costs less.
Change any number below — your result updates instantly, no button to click.
Your details
Results
A negative number means the heat pump costs more to run at these prices.
Measure or improve the real-world result
These tools are relevant to the numbers above; you do not need them to use the calculator.
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How it works
Current cost = heat demand ÷ (efficiency ÷ 100) × fuel price. Heat pump cost = heat demand ÷ COP × electricity price. Savings = current cost − heat pump cost. The result is sensitive to the gap between your electricity and fuel prices: where electricity is expensive relative to gas, savings shrink.
Heat-pump cost at different seasonal COP values
Using 12,000 kWh of annual useful heat, $0.17/kWh electricity, and the default current-system cost of $988 per year.
| Seasonal COP | Heat-pump cost / year | Saving vs current system |
|---|---|---|
| 2.0 | $1,020 | −$32 |
| 2.5 | $816 | $172 |
| 3.0 | $680 | $308 |
| 3.2 | $638 | $351 |
| 4.0 | $510 | $478 |
Examples use the stated assumptions and rounded dollars. Replace every input with your own rates and expected seasonal performance.
Worked example, step by step
Take the default numbers: a home needing 12,000 kWh of heat per year, currently on an 85%-efficient gas boiler at $0.07/kWh, considering a heat pump with a COP of 3.2 against electricity at $0.17/kWh.
Current (gas) cost = 12,000 kWh ÷ 0.85 × $0.07 = $988 per year.
Heat pump cost = 12,000 kWh ÷ 3.2 × $0.17 = $638 per year.
Estimated annual saving = $988 − $638 = $351 per year.
The heat pump wins here specifically because its 3.2 COP more than compensates for electricity costing roughly 2.4× as much per kWh as gas. If electricity cost more than about 2.5-3× the gas price in this scenario, the result would flip and gas would come out cheaper — which is exactly why the calculator asks for your real local prices rather than assuming an answer.
Why the COP you actually get can differ from the spec sheet
Manufacturer COP ratings are usually measured at a specific outdoor temperature (often 7°C / 47°F) — real-world COP drops as it gets colder, because the heat pump has to work harder to extract heat from cold outside air. In a mild climate you might see close to the rated COP most of the year; in a genuinely cold winter climate, average seasonal COP can run noticeably lower than the headline number, especially with an undersized or poorly-installed unit.
Sizing and installation quality matter as much as the equipment itself. A correctly sized heat pump matched to your home's heat loss, installed by someone experienced with heat pumps specifically (not just general HVAC), consistently outperforms an oversized or poorly-commissioned system — even if both have identical spec sheets.
Cold-climate heat pumps (built with enhanced vapor injection or two-stage compressors) hold their COP much better at low temperatures than standard air-source units, at a higher purchase price. If your winters are genuinely cold, run this calculator with a more conservative COP (2.0-2.5 rather than the manufacturer's best-case number) to get a realistic picture.
Find the break-even COP for your rates
The heat pump breaks even on running cost when COP = electricity price × current-system efficiency ÷ current-fuel price. With the defaults, $0.17 × 0.85 ÷ $0.07 = 2.06. That threshold is more useful than a blanket claim that one fuel is always cheaper.
If electricity rises or fuel gets cheaper, the required COP increases. If the home is replacing electric resistance heat, set current efficiency to 100% and enter the same electricity rate as the current fuel price; any seasonal COP above 1 then lowers modeled energy cost.
What this operating-cost result leaves out
This is not a full investment payback. It excludes equipment and installation cost, financing, maintenance, fixed utility charges, cooling savings, rebates, carbon impact and future rate changes. It also assumes both systems deliver the same annual useful heat.
Use the result to screen scenarios, then compare itemized contractor proposals and local tariffs. A heat pump that costs slightly more to run may still be attractive for cooling or electrification; one that looks cheaper on paper can disappoint if backup heat or poor installation lowers seasonal performance.
Sources used for assumptions: U.S. Department of Energy — Heat Pump Systems; U.S. Department of Energy — Energy Saver Guide.
Frequently asked questions
What is COP?
Coefficient of Performance — how many units of heat the pump delivers per unit of electricity. A COP of 3 means 3 kWh of heat for every 1 kWh of power.
Which COP should I enter?
Use an estimated seasonal COP for your climate, supply temperature and system—not the best COP printed for one test condition. If uncertain, compare a conservative, middle and optimistic scenario.
How do I convert my gas price to per kWh?
For U.S. therm billing, divide the variable price per therm by about 29.3 because EIA defines one therm as 100,000 Btu and one kWh as 3,412 Btu. Include variable delivery charges; keep fixed monthly fees separate.
Why might a heat pump cost more to run?
If electricity is expensive relative to the current fuel, the seasonal COP may not be high enough to overcome the price gap. The calculator shows this honestly with a negative saving.
Does a heat pump really provide more than 100% efficiency?
COP compares heat delivered with electricity consumed. Because the system transfers heat rather than converting electricity directly into heat, delivered heat can exceed electrical input.
Does this include resistance backup heat?
Only if your seasonal COP estimate already reflects it. Frequent auxiliary resistance heat lowers the combined seasonal COP, so use a conservative value when backup heat is expected.
Does this calculate payback on installation?
No. It compares annual operating energy cost only. Subtract incentives from installed cost, add maintenance differences, and divide the net extra cost by annual savings for a simple payback estimate.
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