SolarToolsHow This Tool Works
The Heat Pump Payback Calculator compares the operating cost of a heat pump against gas, oil, propane, or electric resistance heating, then calculates how long it takes for the operating savings to recover the install cost. The result depends heavily on three things: your local electricity rate, your fuel price, and the heat pump's COP (Coefficient of Performance) at your winter design temperature.
The math is simple in principle. A heat pump with COP 3.0 moves 3 kWh of heat for every 1 kWh of electricity consumed. So if electricity costs $0.16/kWh, the effective cost of delivered heat is $0.053/kWh. Compare to a gas furnace at $1.20/therm and 85% AFUE: delivered heat costs $0.0141/kWh. Wait — that means gas is cheaper? At those rates, yes. The case for heat pumps collapses when electricity is expensive and gas is cheap (think Massachusetts or Hawaii). It's strongest when electricity is cheap (Pacific Northwest hydro at $0.10/kWh) or when replacing oil/propane (always expensive per BTU).
This calculator also estimates CO₂ reduction, which is often the real reason for switching. Even on a fossil-heavy grid, a heat pump's COP advantage means lower emissions than burning gas directly. On a clean grid (Pacific Northwest, France, Norway), the CO₂ reduction is dramatic.
The payback period depends on your incentives too. The US Inflation Reduction Act provides up to $2,000 in federal rebates for heat pumps, and many states add $1,000–$5,000 on top. Enter the total incentive — it dramatically improves payback.
- Heating load (BTU/hr) = heat loss at your winter design temperature. A Manual J calc gives the precise number; rough estimate: 25–35 BTU/sqft for well-insulated homes, 40–60 for older homes, 70+ for uninsulated.
- Annual heating hours = hours per year your heating actually runs. Cold climates (US Northeast): 2,500+. Mild (US South, coastal): 1,200. Europe: 1,500–2,500.
- COP = rated heating efficiency at 47°F (8°C) outdoor temp. Cold-climate HPs (Mitsubishi Hyper-Heat, Daikin Aurora) maintain COP 2.0–2.5 even at -15°C. Standard HPs drop to COP 1.5 below -10°C.
- Fuel price = local price. Gas: $/therm (US avg $1.20). Oil: $/gallon (US avg $4.00, but varies wildly). Propane: $/gallon ($2.50–$4.00).
- Fuel efficiency = AFUE rating. Modern condensing gas furnaces: 95–98%. Older: 80%. Oil furnaces: 80–88%.
- Install cost = total turnkey. Cold-climate whole-home HP: $12,000–$18,000. Single-zone mini-split: $4,000–$6,000.
The CO₂ estimate uses US average grid intensity (0.7 lbs CO₂/kWh). In cleaner grids (Pacific Northwest, France, Norway), the actual reduction is much larger.
When to Use This Calculator
Why COP matters more than rated efficiency
COP (Coefficient of Performance) is the ratio of heat delivered to electricity consumed. COP 3.0 means 3 kWh of heat per 1 kWh of electricity. The COP varies with outdoor temperature — a heat pump rated at COP 3.5 at 47°F might only deliver COP 2.0 at 17°F. Cold-climate heat pumps (Mitsubishi M-Series, Daikin Aurora, LG Cold Climate) maintain higher COP at low temperatures because they use larger compressors and vapor injection. If you live somewhere cold, a standard heat pump will perform poorly in January — make sure you're pricing a cold-climate unit.
When heat pumps lose to gas
Three conditions: cheap gas, expensive electricity, mild climate. Massachusetts is the canonical example: gas at $1.50/therm and electricity at $0.32/kWh makes heat pump operating costs 3–4× higher than gas. The IRA incentives can close the gap, but operating economics still favor gas. The flip case: Pacific Northwest with $0.10 hydro electricity and gas at $1.40/therm — heat pumps win easily.
When heat pumps always win: oil and propane
Oil at $4.00/gallon and 80% AFUE delivers heat at $0.036/kWh equivalent. A COP 3.0 heat pump at $0.16/kWh delivers at $0.053/kWh. Wait, that's still more expensive? No — recheck. Oil delivers 138,500 BTU/gal × 0.80 = 110,800 BTU = 32.5 kWh of heat per gallon. At $4/gal that's $0.123/kWh. Heat pump at $0.053/kWh wins by 2.3×. Annual savings on 2,000 hours of 40,000 BTU/hr heating: $1,400–$1,800/year. Payback with incentives: 5–8 years.
The HSPF2 rating
HSPF2 (Heating Seasonal Performance Factor) is the seasonal average efficiency, accounting for varying COP across the heating season. HSPF2 of 10 corresponds to average COP of ~2.93. The current minimum in the US (2023+) is 7.5 HSPF2. Cold-climate HPs hit 10–12 HSPF2. Use HSPF2/3.412 to convert to average seasonal COP if you don't have a specific COP number.
Sizing matters more than COP
Most heat pumps are oversized, which causes short cycling and lower efficiency. A properly sized heat pump runs longer at lower output, which is more efficient and dehumidifies better in cooling mode. Manual J calculation (or a similar heat loss analysis) is essential. Avoid contractors who size by square footage rules of thumb.
Frequently Asked Questions
Yes, modern cold-climate heat pumps (Mitsubishi Hyper-Heat, Daikin Aurora, LG Cold Climate) work down to -25°C (-13°F) and maintain COP above 2.0 at -15°C. Over 60% of new Norwegian homes heat with heat pumps.
Depends on your rates. At $0.10/kWh electricity and $1.50/therm gas, heat pump wins. At $0.30/kWh electricity and $1.00/therm gas, gas wins. Use this calculator with your actual rates to find out.
COP = instantaneous efficiency (heat out ÷ electricity in). HSPF2 = seasonal average efficiency in BTU/Wh. To convert: average seasonal COP = HSPF2 / 3.412. Modern cold-climate HPs deliver HSPF2 of 10–12, equivalent to seasonal COP 2.9–3.5.
The federal IRA heat pump credit expired end of 2025. Some states still offer $1,000–$5,000 rebates, and some utilities add $500–$1,500. Check DSIREUSA.org for current programs in your state.
Usually no — the embedded operating savings rarely justify scrapping a working furnace. Wait until the furnace needs replacement (15–20 year lifespan), then switch to a heat pump. The exception: switching from oil or propane, where operating savings are large enough to justify early replacement.
Further Reading
Deep-dive articles and guides related to this calculator.
Cutting Your Electricity Bill: 12 Strategies That Actually Work
Twelve proven strategies to cut your electricity bill, ranked by ROI. From free behavioral changes t...
Home Battery Storage: A Practical Buyer's Guide
LFP vs NMC chemistry, capacity sizing, inverter compatibility, and the real-world economics of home ...
Energy & Solar Glossary
Plain-English definitions of every term used in this calculator and across the site.