Energy & Home · 2026

Heat Pump vs Furnace Calculator

Compare what a heat pump really costs to run against a gas, propane, oil or electric furnace using COP vs AFUE and your local prices — then see payback, a 15-year price-trend projection, and the CO₂ you'd avoid. Works in any country and currency.

Systems & prices

Mild≈3.5 · Moderate≈3.0 · Cold≈2.4 · Very cold≈1.9

Price trends 15-yr projection

Upfront cost & incentives

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COP vs AFUE — the only two efficiency numbers that matter

AFUE (Annual Fuel Utilization Efficiency) is the share of a fuel's energy a furnace turns into heat: 96% AFUE means $0.96 of every $1 of fuel becomes warmth. COP (Coefficient of Performance) is how many units of heat a heat pump moves per unit of electricity — a COP of 3 is effectively 300% efficient, because the pump moves existing heat rather than burning fuel. The catch: a heat pump runs on electricity (often pricier per delivered BTU) and its COP falls as the weather gets colder, while a furnace's efficiency is constant. That tension is exactly what this calculator resolves at your prices.

Gas, propane, oil or electric — pick your real comparison

Most calculators only model natural gas, but the switch math changes completely by fuel. Propane and heating oil deliver heat at roughly $30–$45 per million BTU in many regions — far more than piped gas — so a heat pump usually wins easily against them, often with a payback under five years. Electric resistance (baseboards or an electric furnace) is 100% efficient but pays full retail per kWh, while a heat pump delivers the same warmth for a third of the electricity. Choose your fuel above and the price field, efficiency baseline and emissions factor all update so the comparison is honest for your home.

The cost formula

For an annual heating load Q in BTU: heat-pump cost = Q ÷ (COP × 3,412) × electricity price, furnace cost = Q ÷ (efficiency × BTU-per-unit) × fuel price. At the US natural-gas defaults (electricity $0.165/kWh, gas $1.30/therm, COP 3.0, AFUE 0.95) a 50 million-BTU/yr home runs about $806/yr on a heat pump vs $684/yr on the furnace — gas is slightly cheaper to run until electricity gets cheaper or the COP rises. Switch the fuel to propane or oil and the heat pump typically pulls ahead immediately.

The breakeven COP

The single number that decides it: breakeven COP = (electricity price × BTU-per-unit × efficiency) ÷ (fuel price × 3,412). If your real seasonal COP beats the breakeven, the heat pump is cheaper to run. We show both side by side so you can see how much margin you have — and how a colder winter (which lowers COP) could flip it.

Why a 15-year price trend matters

A switch is a 15-year decision, so a single year's prices aren't enough. Electricity and fossil-fuel prices rarely rise at the same rate — and when gas, propane or oil climb faster than electricity, a heat pump that looks marginal in year one becomes the clear winner by year ten. Set your own expected annual increases under Price trends; the cumulative-savings chart and the year-by-year schedule both compound them, and the breakeven year moves accordingly.

How much CO₂ you'd avoid

Because a heat pump moves three-plus units of heat per unit of electricity, it usually emits less carbon than burning fuel on-site — even on a grid that still uses some fossil generation. We estimate annual and 15-year emissions for both systems using your country's grid carbon intensity and the chosen fuel's combustion factor, then show the reduction in tonnes and tree-equivalents. On a clean grid (hydro, nuclear or lots of renewables) the cut is dramatic; on a coal-heavy grid it's smaller but still usually positive against oil and propane.

The 2026 tax credit & rebates

In the US the federal 25C credit covers 30% of a qualifying heat pump, capped at $2,000 per year, and many state/utility rebates stack on top (editable field above). Outside the US, the credit field becomes a generic national/utility incentive you can enter yourself — many countries run heat-pump grants (the UK's Boiler Upgrade Scheme, Canada's Greener Homes, the EU's national schemes). Because a heat pump both heats and cools, replacing a furnace and an air conditioner together makes the upfront premium much smaller — worth modelling if your AC is also near end of life.

Why cold climates flip the math

A heat pump's COP drops as outdoor temperature falls — a standard unit can sink toward ~1.5 around 5°F / −15°C. Modern cold-climate heat pumps (CCHP) hold a usable COP far lower, and a dual-fuel / hybrid setup keeps a fuel furnace as backup for the coldest hours. Use the climate selector (or lower the COP slider) to stress-test your worst months, and read the hybrid estimate in your results.

Estimates only — actual savings depend on your home, installation quality, weather, and real utility rates. Prices, grid carbon factors and incentives are approximate 2026 averages; edit them for accuracy. Confirm tax-credit or grant eligibility with a professional and current guidance. Not professional energy, tax or financial advice.

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FAQ

Is a heat pump cheaper than gas in 2026?

It depends on your seasonal COP and your local electricity-to-gas price ratio. Compare your COP to the breakeven COP shown above — if it's higher, the heat pump wins on running cost. Against propane, oil or electric resistance it almost always wins.

Does this work for propane, oil and electric heat?

Yes. Choose your fuel in the calculator and the price unit, efficiency baseline and CO₂ factor all update. Propane and oil usually show the fastest payback because their delivered-heat cost is high.

Can I use it outside the United States?

Yes — pick your country at the top and every amount switches to your local currency with national-average prices and grid carbon intensity pre-filled. The US keeps state-level price presets; other countries use a national average you can edit.

Why does the 15-year projection matter?

Fuel and electricity prices rise at different rates. Setting expected annual increases under Price trends compounds them across the schedule, which can move the breakeven year by several years.

How do you estimate CO₂ emissions?

Heat-pump emissions = electricity used × your country's grid carbon intensity; furnace emissions = fuel burned × that fuel's combustion factor. We show annual and 15-year totals plus the reduction in tonnes and trees.

Do heat pumps work in cold weather?

Modern cold-climate heat pumps keep heating well below freezing; their COP just drops as it gets colder. A dual-fuel/hybrid system pairs one with a fuel backup for the coldest hours — see the hybrid estimate in your results.

What's the $2,000 tax credit?

The US federal 25C credit returns 30% of a qualifying heat pump's cost, up to $2,000 per year. State and utility rebates can stack on top. Outside the US, enter your national grant in the incentive field.

Heat pump vs furnace lifespan?

Furnaces often last 15–20 years; heat pumps roughly 12–15 (they also provide cooling, replacing a separate AC). Factor replacement timing into total cost of ownership.

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