Heat Pump Payback Calculator
Enter your current heating bill, the heat pump's efficiency rating, your electricity rate, and the install cost. You'll see how many years until it pays for itself, how much you save each year, and how much CO2 you'll cut. Nothing uploaded.
Break-Even
Time until the heat pump has paid for itself through energy savings
Annual Summary
Full savings breakdown
Running Cost Comparison
15-Year Cumulative Savings
Learn more: what drives heat pump payback
Two cost lines and one gap
Your current heating cost is units of fuel times the unit price. For the heat pump the calculator first turns your fuel into heat delivered: units times energy per unit times your old system's efficiency. It divides that heat by the COP to get the electricity needed, then multiplies by your electricity rate. Break-even is the net install cost, after incentives, divided by the yearly saving.
The energy figures come from the EIA's conversion table: 100,000 Btu per therm, 138,500 Btu per gallon of heating oil, 91,452 per gallon of propane and 3,412 Btu per kWh. That is 29.3 kWh per therm, 40.6 kWh per gallon of oil and 26.8 per gallon of propane.
Two worked examples
Take 800 therms of gas a year at $1.35, which costs $1,080, in a furnace at 80% efficiency. That is 18,752 kWh of heat. At a COP of 3 the heat pump needs 6,251 kWh, which is $875 at $0.14 per kWh. The saving is $205 a year, so an $8,000 net install takes about 39 years to pay back.
Now take 600 gallons of heating oil at $3.80, which costs $2,280, in a boiler at 85%. That is 20,706 kWh of heat, 6,902 kWh of electricity at COP 3 and $966 a year. The saving is $1,314 and the same $8,000 pays back in about 6.1 years. The fuel you replace matters more than almost any other input.
Carbon and cost are separate sums
The CO2 figure compares the fuel's combustion emissions with the emissions from the electricity the heat pump uses. The calculator uses 11.7 lb of CO2 per therm of gas, 22.4 per gallon of oil and 12.7 per gallon of propane. For electricity it uses 0.767 lb per kWh, the US average of 767 lb per MWh in EPA's eGRID data for 2023. In the gas example that saves about 4,570 lb of CO2 a year even though the money saved is small.
FAQ
Does a higher COP always shorten payback?
Yes, with everything else equal, because the COP divides the heat demand before the electricity rate is applied. A COP of 4 uses a quarter less electricity than a COP of 3 for the same heat.
Why does the fuel type change the results so much?
Fuels differ in price per unit of heat and in CO2 per unit of energy. In the examples, oil costs far more per kWh of heat than gas, so replacing it saves much more money and CO2.
What if the annual saving is negative?
Then there is no payback and the calculator reports that it never breaks even. A low COP, an expensive electricity rate or an already cheap fuel can all cause this.