Energy Costs · Calculator
Heat Pump Running Cost Calculator: Heating, Cooling and Annual Cost
Heat pump electricity = heat delivered (BTU) ÷ (COP × 3,412). At an average COP of 2.8, delivering 30,000 BTU/h for 10 hours takes about 31 kWh, roughly $5.34 a day at $0.17/kWh, while electric resistance heat would need about 88 kWh for the same warmth. Real COP falls as it gets colder outside, so cold snaps cost more per hour of heat. Cooling follows the same logic with SEER2: kWh = tons × 12,000 × full-load hours ÷ (SEER2 × 1,000), so a 3-ton, 15.2 SEER2 system running 8 full-load hours a day for 4 months costs about $387 a year to cool.
Heat pump running cost calculator
The formula
COP (coefficient of performance) is heat delivered divided by electricity used, in the same units. Since 1 kWh equals 3,412 BTU, a heat pump with a COP of 3 delivers 3 × 3,412 = 10,236 BTU for every kWh it draws.
Heat pump kWh = Heat load (BTU/h) × Hours ÷ (COP × 3,412)
Resistance kWh = Heat load (BTU/h) × Hours ÷ 3,412
Cost = kWh × Rate ($/kWh)
Annual heating cost = Monthly heating cost × Heating months
Cooling kWh per year = Tons × 12,000 × Full-load hours per day × Days × Cooling months ÷ (SEER2 × 1,000)
Annual total = Annual heating cost + Annual cooling cost
Electric resistance heat (baseboard, strip heat, an electric furnace or a space heater) always has a COP of 1, which is why the comparison is a simple ratio: a heat pump at COP 2.8 uses 1 ÷ 2.8, about 36%, of the electricity resistance heat would need.
If you enter an HSPF2 rating, the calculator converts it to a seasonal COP (HSPF2 ÷ 3.412) and uses that in place of the COP field. SEER2 is in BTU per watt-hour, so dividing cooling BTU by SEER2 × 1,000 gives kWh directly.
Worked example
With the calculator defaults: 30,000 BTU/h delivered for 10 hours a day, 30 days a month, average COP 2.8, 5 heating months, $0.17/kWh; for cooling, a 3-ton 15.2 SEER2 system at 8 full-load hours a day for 4 months.
- Heat per month: 30,000 × 10 × 30 = 9,000,000 BTU
- Heat pump: 9,000,000 ÷ (2.8 × 3,412) = 942 kWh, about $160.15 a month
- Annual heating: $160.15 × 5 months ≈ $801
- Cooling: 3 × 12,000 × 8 × 30 × 4 ÷ (15.2 × 1,000) = 2,274 kWh, about $387 a year
- Annual total: $801 + $387 ≈ $1,187
Resistance heat for the same monthly heat would need 9,000,000 ÷ 3,412 = 2,638 kWh, about $448.42 a month, so the heat pump saves about $288 a month in heating. Per day, it uses about 31.4 kWh ($5.34) against 87.9 kWh ($14.95).
Choosing a realistic COP
COP depends mostly on outdoor temperature. Use the average temperature for the period you are estimating:
| Average outdoor temp | Typical COP, standard heat pump | Typical COP, cold-climate heat pump |
|---|---|---|
| 45–50 °F | 3.3–4.0 | 3.8–4.5 |
| 30–35 °F | 2.6–3.1 | 2.9–3.5 |
| 15–20 °F | 2.0–2.5 | 2.4–3.0 |
| 0–5 °F | 1.4–1.9 (with backup heat running) | 1.8–2.3 |
For a whole-season estimate, convert the unit's rating: seasonal COP = HSPF2 ÷ 3.412, so a 7.5 HSPF2 heat pump averages about 2.2 and a 9.5 HSPF2 one about 2.8. Type the HSPF2 into the calculator and it does this conversion for you. The full curve is on heat pump efficiency vs temperature, and ratings are explained on the HSPF2 page. To work out COP from measurements, use the COP calculator.
Estimating your average heat load
The load input is the heat your house actually needs while the system runs, not the heat pump's nameplate size. Three ways to estimate it, from roughest to best:
- From the nameplate: in mild-to-cool weather a correctly sized heat pump delivers close to its rated output while running. Use about 70–100% of the rated BTU/h and adjust the hours.
- From design heat loss: if you know the design heat loss (from a Manual J or the heating BTU calculator), the load scales roughly with the indoor-outdoor temperature difference. A house losing 40,000 BTU/h at 5 °F (60 °F below a 65 °F balance) loses about 20,000 BTU/h at 35 °F.
- From past bills: if you heated with gas, therms × AFUE × 100,000 gives the BTU actually delivered per month. Divide by the hours in the month and enter that with 24 run hours to get an average load.
Accounting for backup heat
Below the balance point, a heat pump can't keep up alone and electric strips (or a furnace in a dual-fuel system) add heat at a COP of 1. The calculator assumes the heat pump supplies everything. If backup supplies part of the heat, blend the two:
Effective COP = 1 ÷ (Heat pump share ÷ Heat pump COP + Backup share ÷ 1)
For example, if the heat pump supplies 80% of the heat at COP 2.8 and strips supply 20%, the effective COP is 1 ÷ (0.8 ÷ 2.8 + 0.2) ≈ 2.06. Enter that in the calculator to see the real cost. Correct heat pump sizing and an auxiliary heat lockout on the thermostat keep the backup share small.
Heat pump vs gas
One therm of gas holds 100,000 BTU. At COP 2.8 and $0.17/kWh, a heat pump delivers 100,000 BTU of heat for 100,000 ÷ (2.8 × 3,412) ≈ 10.5 kWh, about $1.78. A 95% AFUE furnace burns about 1.05 therms for the same heat, so the heat pump is cheaper whenever gas costs more than roughly $1.69 per therm at these numbers. Cheaper electricity, a higher COP or pricier gas all move the line in the heat pump's favor; colder weather moves it toward gas. See gas vs electric heating, AFUE ratings and the heating cost calculator for a full comparison.
Ways to lower heat pump running cost
- Avoid deep setbacks. A big morning recovery is the most likely time for strips to engage. A setback of 2–3 °F, or none, often costs less overall.
- Keep airflow up. Dirty filters and closed registers lower COP.
- Keep the outdoor unit clear of snow, leaves and ice so it can defrost and breathe.
- Seal and insulate. Every BTU of heat loss you remove saves 1 ÷ COP worth of kWh, and reduces how often backup heat runs.
- Use off-peak rates where available by preheating slightly before the expensive period.
For comparison with other electric heating, see cost to run an electric heater.
Frequently asked questions
How much does it cost to run a heat pump per month in winter?
For a typical 2,000 sq ft home in a mixed climate, often $100–$250 a month in the coldest months at $0.17/kWh, depending on insulation, temperatures and COP. Cold climates and leaky homes can exceed that.
Is a heat pump cheaper to run than electric baseboard?
Yes, almost always. At a typical COP of 2–3.5 it uses a half to under a third of the electricity for the same heat, and even at COP 1.5 it uses a third less.
Does a heat pump cost more to run when it's colder?
Yes, for two reasons: the house needs more heat, and each kWh delivers less heat because COP falls. A day at 10 °F can cost two to three times as much as a day at 40 °F.
What does a heat pump cost to run for a whole year?
Add the heating and cooling seasons. With the calculator defaults (5 heating months at about $160 a month, plus 4 cooling months for a 3-ton 15.2 SEER2 system), the total is about $1,190 a year at $0.17/kWh. Cooling is usually the smaller share outside hot southern climates; the SEER2 page explains the cooling rating.
Last reviewed 2026-10-28