Heat Pump Savings Calculator
Estimate how much a heat pump could save (or cost) each year versus your gas furnace, based on your local energy prices and equipment efficiency.
Reviewed by the CalcCafe editorial team · Last updated 1 July 2026 · How we test our tools
Example
Heating 600 therms/yr where gas is $1.60/therm and a 95% furnace burns 600 × 1.60 ÷ 0.95 = $1,011 a year. A heat pump with a COP of 3.5 uses 600 × 29.3 ÷ 3.5 ≈ 5,023 kWh; at $0.13/kWh that is $653. The heat pump saves about $358 per year — roughly 35% off the heating bill.
How it works
Gas cost = therms × gas price ÷ (furnace efficiency ÷ 100). The same heat, 29.3 kWh per therm, is delivered by a heat pump using kWh = therms × 29.3 ÷ COP, costing kWh × electricity price. Annual savings = gas cost − heat pump cost, which can be negative when electricity is expensive relative to gas.
Good to know
A heat pump moves heat instead of burning fuel, so a single unit of electricity can deliver two to four units of heat — that multiplier is the coefficient of performance, or COP. This calculator pits that efficiency against a gas furnace by converting your yearly heating load, measured in therms, into the electricity a heat pump would need to produce the same warmth, then pricing both at your local rates.
The result hinges on the gap between gas and electricity prices in your area. Where gas is cheap and electricity is pricey, a heat pump can actually cost more to run, which is why the savings figure is allowed to go negative. Where electricity is reasonable and gas is expensive, or where a cold-climate heat pump holds a high COP through winter, the savings can be substantial. Seasonal COP matters: a nameplate COP of 3 or 4 drops in very cold weather, so use a realistic whole-season average rather than the best-case lab number.
To find your inputs, check a full year of utility bills. Add up your winter therms for the heating figure, and read the per-therm and per-kWh prices, including delivery charges, from the bills themselves. Furnace efficiency is the AFUE rating on the unit; 80% is common for older furnaces and 90–98% for modern condensing models.
This is a running-cost comparison only. It ignores equipment and installation price, available rebates or tax credits, backup heating, and any air-conditioning value a heat pump adds in summer. Treat it as a first-pass estimate and confirm with quotes and a load calculation before committing.
Frequently asked questions
Why might a heat pump cost more to run than gas?
When electricity is expensive relative to natural gas, the heat pump's efficiency advantage can be outweighed by the higher price per unit of energy. In some regions with very cheap gas the calculator will show a negative saving, meaning gas is cheaper to run at those prices.
What COP should I use?
Use a realistic seasonal average, not the peak lab rating. Many air-source heat pumps average around 2.5–3.5 over a heating season, while cold-climate models hold higher COPs in freezing weather. Lower it if your winters are severe.
Is my data uploaded anywhere?
No — this calculator runs entirely in your browser. Your inputs never leave your device, and it works offline once loaded.
Is this calculator free?
Yes, completely free with no sign-up and no limits.
People also ask
How much can a heat pump save per year?
It varies widely with local energy prices and efficiency. Households replacing an older furnace where electricity is moderately priced often save a few hundred dollars a year, while others break even or pay more. Enter your own rates and therms to see your figure.
How many kWh does a heat pump use per therm of heat?
One therm equals about 29.3 kWh of heat. A heat pump with a COP of 3 delivers that heat using roughly 29.3 ÷ 3 ≈ 9.8 kWh of electricity, which is why heat pumps can be far more efficient than resistance heating.
Does furnace efficiency matter in the comparison?
Yes. A 95% furnace wastes only 5% of the gas it burns, so it needs less fuel than an 80% unit for the same heat. Higher furnace efficiency raises the bar a heat pump must beat, shrinking the estimated savings.
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Sources & references
These tools follow our methodology and provide educational estimates only — verify important figures with a qualified professional.