How Much Does It Cost to Run a Heat Pump?
About $4.48 a day for a 3-ton heat pump drawing 3.5 kW for 8 hours at a COP of 3, on $0.16/kWh electricity — roughly $134 a month. That is 28 kWh buying 286,608 BTU of heat, which the same electricity could not have come close to making on its own. Set your own unit, runtime and weather below.
Mode
Compressor and air handler together — 3.0 tons of heat at this efficiency.
Hours the compressor is turning. A variable-speed unit runs longer at lower power for the same kWh.
Units of heat per unit of electricity. Falls as it gets colder. Equivalent to an HSPF of 10.2.
Backup heat (the resistance strips)
When it gets cold enough that the compressor cannot keep up, electric strips in the air handler take over. They are a space heater the size of your house: one unit of heat per unit of electricity, no better. Leave this at zero for a mild day, then try two hours.
An hour of 10 kW strips costs $1.60 and buys the heat the compressor buys for $0.53.
Cost to run this heat pump, per day
$4.48
8 hours at $0.56 an hour — $134.40 a month, or $672.00 across a 150-day heating season.
Electricity used
28.0 kWh
a day, at the meter
Heat delivered
287k BTU
a day, at 35,826 BTU/hr — 3.0 tons
Price of that heat
$15.63
per million BTU delivered — the gas furnace's is $16.63
3.5 kW × 8 hours = 28.0 kWh × $0.16 = $4.48 = $4.48 a day. The compressor moved 35,826 BTU/hr into the house for that — 3 times what the same electricity would have made as resistance heat. That multiple, not the wattage, is the whole argument for a heat pump.
What the same heat would cost from a gas furnace
An 80,000 BTU/hr furnace at 95% AFUE buys heat at $16.63 per million BTU at $1.50/therm, blower included. This heat pump's compressor buys it at $15.63. The heat pump is the cheaper heat here, by $1.00 per million BTU.
At $0.16/kWh and $1.50/therm, the heat pump needs a COP of 2.82 to break even with that furnace. Hold the COP at 3 instead and the two swap places when electricity passes $0.170/kWh, or when gas falls below $1.40/therm. Everything about this comparison is local: it is decided by your two utility prices and the weather, not by which machine is “better”.
Check the runtime against your own electricity bill
Implied compressor runtime
171 h · 5.7 h/day
At 3.50 kW, 600 kWh is 171 hours of running, or 5.7 hours a day over a month. Take a shoulder-season bill from the same house — April or October, when neither heating nor cooling runs much — and subtract it first; what is left is the heat pump rather than the fridge and the lights. If the answer comes out impossibly high, the strips were running and this arithmetic has quietly attributed their kilowatt-hours to the compressor.
A COP is units of heat moved per unit of electricity consumed; a kWh is 3,412 BTU, so an HSPF or SEER divided by 3,412 is a COP. The wattage is the whole system, air handler included, which is what HSPF and SEER are measured on. COP falls as the outdoor temperature falls and the preset tiers here are round numbers to reason with, not a spec sheet for any particular unit — your own will have its own curve, and defrost cycles will shave a little off it. Backup strips are charged at a COP of 1. Monthly figures use a 30-day month, and both the heating and cooling seasons are the 150-day assumptions used across this site — shorten or lengthen them for your climate. Nothing here includes equipment or installation. Not sure of your electricity rate? Check average rates by state.
How much electricity does a heat pump use?
Daily cost = watts ÷ 1,000 × compressor hours × your rate
That is the whole formula, and notice what is missing from it: efficiency. A heat pump’s COP does not appear anywhere in the cost of an hour of running. It appears in what that hour buys. Two heat pumps drawing 3.5 kW cost the same per hour; the better one simply puts more heat in the house and can stop sooner.
Worked example (3-ton unit, 3,500 W, 8 hours, COP 3, $0.16/kWh): 3,500 ÷ 1,000 = 3.5 kW × 8 hours = 28kWh × $0.16 = $4.48 per day, or $134.40 over a 30-day month. Those 28 kWh delivered 35,826 BTU/hr of heat, 3 times what they would have produced in a resistance heater.
Daily cost by compressor runtime and unit size
Rows are hours the compressor is actually turning. Columns are nominal sizes, shown as the draw each needs to make its rated heat at COP 3. There is no COP column, because there is no COP in this arithmetic.
| Compressor runtime | 2 ton2,350 W | 2.5 ton2,950 W | 3 ton3,500 W | 4 ton4,700 W | 5 ton5,850 W |
|---|---|---|---|---|---|
| 2 hours a day | $0.75 | $0.94 | $1.12 | $1.50 | $1.87 |
| 4 hours a day | $1.50 | $1.89 | $2.24 | $3.01 | $3.74 |
| 8 hours a dayTypical cold-month average | $3.01 | $3.78 | $4.48 | $6.02 | $7.49 |
| 12 hours a day | $4.51 | $5.66 | $6.72 | $9.02 | $11.23 |
| 16 hours a dayA hard freeze, or a variable-speed unit loafing all day | $6.02 | $7.55 | $8.96 | $12.03 | $14.98 |
At $0.16/kWh. Long runtimes are not a fault: a variable-speed heat pump is designed to run most of the day at a fraction of its full draw, which is more comfortable and no more expensive per kilowatt-hour. Find your own rate on the rates by state page.
What COP changes is the hours, and the price of the heat
Every row below meets the same demand — the 286,608 BTU our anchor unit delivers in a day — from the same 3.5 kW compressor. As the weather turns and the COP falls, the machine does not get more expensive by the hour. It needs more hours.
| Conditions | Heat delivered | Runtime a day | Per million BTU | Per day |
|---|---|---|---|---|
| COP 4.0Mild — near the 47°F rating point | 47,768 BTU/hr | 6.0 h | $11.72 | $3.36 |
| COP 3.0Cool — a moderate heating-season day | 35,826 BTU/hr | 8.0 h | $15.63 | $4.48 |
| COP 2.2Cold — near the 17°F rating point | 26,272 BTU/hr | 10.9 h | $21.32 | $6.11 |
| COP 1.5Deep cold — approaching the balance point | 17,913 BTU/hr | 16.0 h | $31.26 | $8.96 |
| Emergency heat10 kW of strips, compressor off | 34,120 BTU/hr | 8.4 h | $46.89 | $13.44 |
If your unit’s label gives an HSPF rather than a COP, divide by 3.412 — a watt-hour is 3,412 BTU, so the two numbers are the same ratio in different clothes. COP 3 is an HSPF of about 10.2. The tiers above are round numbers for reasoning with, not a spec sheet: every unit has its own curve, and defrost cycles shave a little more off it in damp cold.
Heat pump vs. gas furnace cost comparison
Gas is billed per therm and electricity per kilowatt-hour, so the two can only be compared in the currency the house cares about: heat delivered. Every row below puts the same 286,608 BTU into the house each day and differs only in what that costs. The result is closer than either side of the argument usually admits.
| System | Runtime a day | Energy a day | Per million BTU | Per day | Per season |
|---|---|---|---|---|---|
| Heat pump, COP 3Moderate weather — this page’s anchor | 8.0 h | 28 kWh | $15.63 | $4.48 | $672 |
| Heat pump, COP 2.2Cold — near the 17°F rating point | 10.9 h | 38 kWh | $21.32 | $6.11 | $916 |
| Gas furnace, 95% AFUE80,000 BTU/hr at $1.50/therm | 3.8 h | 3.02 therms | $16.63 | $4.77 | $715 |
| Resistance heat, COP 1Backup strips, or an electric furnace | 8.4 h | 84 kWh | $46.89 | $13.44 | $2016 |
Electricity at $0.16/kWh, gas at $1.50/therm, a 150-day season, and the furnace charged for its 400W blower on every burner hour. Fuel only — equipment and installation are outside this comparison, and they are where a heat pump’s real disadvantage usually lies. Full detail on the gas side is on our cost to run a furnace page.
The three numbers worth remembering
A million BTU of heat costs $15.63 from the heat pump at COP 3 and $16.63 from the gas furnace — a margin of about 6%, which is nothing. So the comparison turns on three break-evens. The heat pump needs a COP of 2.82 to draw level. Hold it at COP 3 and gas wins once electricity passes $0.170/kWh, or once gas falls below $1.40/therm. None of these is a fact about heat pumps. They are facts about your two utility bills.
Which means the answer is regional
39 of the 51 state average rates sit below $0.170/kWh, so a COP-3 heat pump beats a 95% furnace in most of the country at these gas prices — and loses in the rest. In Hawaii, at $0.39/kWh and the highest average in this data, the heat pump would need a COP of 6.8 to keep up — which no air-source unit will manage in any weather. Gas prices swing by region and season far more than electricity does, so run the calculator with the two numbers off your own bills rather than trusting either figure here. Rates by state are on this site; the therm price is on your gas bill.
Efficiency above 100% is not a trick
A COP of 3 means three units of heat out for one unit of electricity in, which sounds like it breaks something. It does not: two of those three units were already outdoors, and the heat pump spent its electricity carrying them inside rather than creating them. That is why COP is not comparable with AFUE, and why efficiency ratings can never be compared across fuels. It is also why resistance heat — a space heater, an electric furnace, the backup strips — is stuck at a COP of 1 and costs 3.0 times as much per BTU as the compressor beside it.
Seasonal cost breakdown: heating vs. cooling mode
A heat pump is an air conditioner with a reversing valve. In July it takes heat out of the house; in January it runs the same refrigerant the other way and brings heat in. Same compressor, same coils, near enough the same quantity of heat moved each day — and two quite different bills.
Heating season (150 days)
$672
Cooling season (150 days)
$432
Both seasons
$1104
| Mode | Efficiency | Draw | Heat moved a day | Per million BTU | Per day |
|---|---|---|---|---|---|
| Heating30°F air to a 70°F house | COP 3.0 | 3,500 W | 287k BTU in | $15.63 | $4.48 |
| Cooling75°F house to 95°F air | SEER 16 = COP 4.69 | 2,250 W | 288k BTU out | $10.00 | $2.88 |
Both rows are the same 3-ton unit at 8 hours a day and $0.16/kWh. Season lengths are stated assumptions — five 30-day months each, the same 150-day cooling season our central AC page uses. Shorten one and lengthen the other for your climate; a Gulf Coast house and a Minnesota one share almost nothing here but the hardware.
Why winter costs 56% more
It is the lift. In summer the unit moves heat from a 75°F house into 95°F air, a climb of twenty degrees. In winter it pulls heat out of 30°F air and delivers it at 70°F — twice the climb, and from a source that has less heat in it to begin with. Efficiency falls as the lift grows, which is thermodynamics rather than a defect, so the same box moves heat at $10.00 per million BTU in July and $15.63 in January. Everything else follows from that one fact.
And why summer is the predictable season
Cooling has no backup strips. A heat pump in a heat wave gets gradually less efficient and runs longer; a heat pump in a cold snap hits a wall and hands the job to resistance heat at 4.7 times the summer price of moving the same BTU. That asymmetry — not the raw cost of either season — is what makes winter bills surprising and summer bills merely large.
Why heat pump bills spike in a cold snap
Below a certain outdoor temperature — the balance point — a heat pump cannot make as much heat as the house is losing, however long it runs. At that point electric resistance strips in the air handler switch on to cover the shortfall. They are the same technology as a toaster, at a COP of 1, and they draw whole kilowatts: 10 kW is common, which is nearly three times the compressor beside it.
The table holds the house at the same comfort on a cold day — the 286,608 BTU demand, with the compressor down to COP 2.2 — and hands more of the work to the strips in each row. The heat is identical. Only the bill moves.
| Strip runtime | Compressor hours | Per million BTU | Per day | vs. no strips |
|---|---|---|---|---|
| None — compressor only | 10.9 h | $21.32 | $6.11 | — |
| 1.0 hours | 9.6 h | $24.36 | $6.98 | +14% |
| 2.0 hours | 8.3 h | $27.41 | $7.85 | +29% |
| 4.0 hours | 5.7 h | $33.50 | $9.60 | +57% |
| 8.4 hours“Emergency heat” — the whole day on strips | 0.0 h | $46.89 | $13.44 | +120% |
10 kW of strips at $0.16/kWh, replacing compressor heat hour for hour at constant delivered BTU. Strip capacity varies by air handler; a bigger bank makes the last row worse, not better.
Never leave it on “emergency heat”
That switch locks the compressor out and runs the strips alone — the bottom row of the table, $13.44 a day against $6.11. It exists for when the outdoor unit has failed. It is not a “colder outside” setting, and a surprising number of winter bills are explained by someone flipping it in November and forgetting.
Set back gently, or not at all
A furnace recovers from a deep overnight setback by burning harder. A heat pump has no “harder”, so many thermostats call the strips in to make up a large morning climb — and an hour of those can undo a night of savings. Two degrees is safe; eight is a gamble. A thermostat that knows it is driving a heat pump will start the recovery early on the compressor alone.
Find out whether the strips are running
Most thermostats show “aux heat” or “auxiliary” when they are. If yours does not, the electricity bill will: a day on strips draws several times the kilowatt-hours of a compressor day, which the calculator above will show you if you feed it a month of kWh. A balance point set too high — so the strips join in earlier than they need to — is a common and fixable installation fault.
Reduce the demand, not the machine
Everything above multiplies hours by the cost of an hour. Sealing, insulation and duct work cut the heat the house sheds, which lowers the balance point and keeps the strips off for more of the winter — the one upgrade that pays on both seasons and on whatever equipment comes next. More in our energy savings guide.
Related Guides
Cost to Run a Furnace
The other side of this comparison — gas and electric furnaces priced per BTU
Cost to Run Central AC
What this same box costs in summer, by tonnage and SEER
Space Heater vs. Central Heat
Heat pump, gas furnace and electric furnace compared per room
Cost to Run a Space Heater
Resistance heat at COP 1, which is what the backup strips are
Electricity Rates by State
The number that decides whether a heat pump beats gas where you live
How to Save on Energy Bills
Practical tips by room with savings
Frequently Asked Questions
How much electricity does a heat pump use?
About 28 kWh on a typical heating-season day. A 3-ton unit draws roughly 3.5 kW with the compressor running, and on an average cold-month day the compressor runs something like 8 hours — so 3.5 × 8 = 28 kWh, which is $4.48 at the US average $0.16/kWh, or about $134 a month. Two cautions. That wattage is the compressor and air handler only: if the backup resistance strips run, they add 10 kW or so on top and dwarf everything else. And a variable-speed unit will show you a smaller wattage for more hours — the kilowatt-hours, not the watts, are what the meter counts.
Is a heat pump cheaper to run than a gas furnace?
At US average prices, narrowly yes — and it is genuinely close. A heat pump at a COP of 3 buys a million BTU of heat for $15.63 at $0.16/kWh. A 95% AFUE gas furnace buys the same million BTU for $16.63 at $1.50/therm. The heat pump needs a COP of 2.82 just to draw level, which it clears in mild weather and misses in a cold snap. Flip it around and the answer is a rate: at COP 3 the gas furnace wins once electricity passes $0.170/kWh, which 12 of the 51 state averages exceed. There is no universal answer here, only your two utility prices.
Why did my heat pump bill double during the cold snap?
Almost certainly the backup resistance strips, not the compressor. When it gets cold enough that the heat pump cannot meet the house's demand on its own, electric strips in the air handler switch on to make up the difference. They are resistance heat — one unit of heat per unit of electricity, a COP of exactly 1 — so they buy heat at $46.89 per million BTU against the compressor's $15.63, roughly 3.0 times the price. On the cold day modelled on this page, letting the strips carry the load for four of the day's hours takes it from $6.11 to $9.60 — 57% more for exactly the same warmth. The compressor did not get more expensive; something far worse quietly took over for it.
What is a good COP, and how does it relate to HSPF?
They are the same ratio in different units. HSPF is quoted in BTU of heat per watt-hour of electricity; a COP is that ratio with the units cancelled. Since a watt-hour is 3.412 BTU, dividing an HSPF by 3.412 gives a seasonal COP — so a COP of 3 is an HSPF of about 10.2, and a SEER of 16 in cooling is a COP of 4.69. What counts as "good" depends entirely on where you live, because COP is not a constant: it falls as the outdoor temperature falls, since the heat has further to climb. Heat pumps are rated at 47°F and 17°F for exactly this reason. A unit that never sees a hard freeze spends its life near the top of its curve; one in Minnesota does not.
Does a heat pump cost more to run in winter or summer?
Winter, and by more than most people expect from a machine that moves nearly the same amount of heat each way. On this page's assumptions the heating season costs $672 and the cooling season $432 — about 56% more — for 287k BTU of heat delivered a day against 288k BTU removed. The reason is the temperature lift. In summer the unit moves heat from a 75°F house into 95°F air, a climb of twenty degrees. In winter it pulls heat out of 30°F air and delivers it at 70°F: twice the climb, from a colder and thinner source. Efficiency falls as the lift grows, so the same box buys heat at $15.63 per million BTU in January and moves it at $10.00 in July.
Should I turn my heat pump down at night?
Modest setbacks are fine. Deep ones can cost you, and the reason is peculiar to heat pumps. A furnace recovers from a setback by burning harder for a while; a heat pump has no "harder" — its capacity is what the weather allows. Ask it to climb several degrees quickly on a cold morning and many thermostats will bring the 10 kW resistance strips on to help, and an hour of those undoes a night of savings. Set back by a couple of degrees rather than eight, or use a thermostat that knows it is driving a heat pump and starts the recovery early on the compressor alone. Deep setbacks are sound advice for a gas furnace; the strips are what make a heat pump different.