Heat pump
How much electricity does a heat pump use?
1,500–5,000 W draw · COP 2.5–4 · $40–$120 per month
A heat pump draws 2,500 W and might deliver 7,500–10,000 W of heating. That ratio is the coefficient of performance (COP), and it is why the calculator above understates the value: you should enter the heat pump's actual electricity draw, not its heating output.
What COP means in dollars
- Resistance heater (any type): COP 1.0 — one kWh in, one kWh of heat out
- Modern air-source heat pump: COP 2.5–4.0 in mild weather
- Ground-source: COP 3.5–5.0, more stable year round
At a COP of 3, a heat pump delivers the same warmth as a space heater for a third of the electricity. If a space heater costs $60 a month, the equivalent heat pump costs about $20.
COP is not constant
Efficiency drops as the outdoor temperature falls. A unit rated COP 4.0 at 10°C may be 2.2 at −5°C and struggle below −15°C. This is why cold-climate models are rated separately, and why a heat pump is often paired with a backup element for the coldest days.
Where it loses
Defrost cycles in humid cold weather run reversed for several minutes at a time, drawing power without heating. In regions with wet winters this can consume 5–10% of annual energy.
Frequently asked questions
How many watts does a heat pump use?
1,500–5,000 W draw. The figure on the rating label is the maximum draw; actual use varies with settings, age and usage pattern.
How much does it cost to run a heat pump per month?
With the defaults above it comes to the monthly figure shown in the calculator. At 16.5¢/kWh — the US residential average — that is a realistic middle estimate. Your own bill may be 30% lower or higher depending on state.
Is it cheaper to run a heat pump at night?
Only if your utility offers a time-of-use plan and you avoid the 4pm–9pm peak window. On a flat-rate plan, the time of day makes no difference to the total.
Does the calculator account for real-world duty cycles?
Not automatically — you enter the effective hours yourself. For compressing appliances like refrigerators and AC units, enter the running watts and roughly the proportion of time the compressor is on, which is usually 30–50%.
Will a newer heat pump actually save money?
Compare the kWh figure in the calculator against an Energy Star model's stated annual use. If the difference is a few hundred kWh a year, the payback on a replacement is usually long; if it is over 500 kWh, it is worth pricing out.