Phase 3 · Sustainable Transitions
Heat Pump Savings Calculator
Swapping a gas furnace for a heat pump can shrink your heating bill — or quietly raise it. The answer is all in your local energy prices and efficiency. Run yours before you commit.
How much can a heat pump save per year?
Annual savings = your gas heating cost minus the heat pump's electricity cost. Gas cost is heat demand (therms) ÷ AFUE × gas price; heat pump cost is (heat demand × 29.3 kWh) ÷ COP × electricity rate. The answer swings entirely on your local gas-to-electricity price ratio and the pump's real COP — with cheap gas and expensive power, a furnace can still cost less.
- 1 therm = 29.3 kWh of delivered heat — the conversion that puts both systems on the same basis so only price and efficiency differ.
- COP (Coefficient of Performance) is heat delivered ÷ electricity consumed. At COP 3 the heat pump uses a third of the energy to deliver the same heat.
- COP falls as it gets colder, so a cold-climate seasonal average is lower than the rating — model conservatively and budget for backup heat.
- Payback on the equipment = install premium ÷ annual savings, and federal, state or utility rebates cut that premium directly.
Under the hood
The math, fully exposed
Both systems deliver the same heat; we price the energy each one burns to do it (1 therm = 29.3 kWh of heat):
- COP is the whole story: at COP 3 the heat pump uses a third of the energy to deliver the same heat — but a cold-climate average COP can be lower, so model conservatively.
- It's a price race, not just efficiency: the result swings on the ratio of your electricity price to your gas price. Cheap gas can keep a furnace ahead even against an efficient heat pump.
- Carbon isn't priced here: a heat pump on a clean grid cuts emissions even when the dollar savings are slim — a real benefit this cost-only model doesn't capture.
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