What electric heating actually draws
"Electric heat" covers two machines that behave nothing alike, and confusing them is the single largest source of bad estimates in household energy.
An air-source heat pump does not make heat. It runs a refrigeration cycle backwards, collecting warmth from outdoor air — which contains plenty even at 35°F — and moving it indoors. Moving heat costs far less than creating it, so a heat pump warming a typical home draws roughly 3,000 to 5,000 W, about what the same equipment draws running as an air conditioner in summer.
An electric resistance furnace makes heat, by pushing current through banks of nichrome strip elements. To warm the same house it draws 10,000 to 25,000 W. That is three to five times the electricity for identical comfort, from equipment that looks similar, sits in the same closet and is wired to the same panel.
The complication is that most heat pumps contain resistance strips too, as backup. When the outdoor temperature drops below the system's balance point, or when the thermostat demands a large temperature rise quickly, those strips energise alongside the compressor. Selecting "Emergency Heat" locks the compressor out entirely and runs the strips alone. This is why a house with a heat pump can see a January bill triple with no change in behaviour: for part of that month it was not running a heat pump at all.
The 3.5 hours a day used here is heating-season compressor run time. EIA's 2020 survey measured 2,484 kWh a year for electric space heating per household that uses it.
What that costs, worked through
Watts × hours ÷ 1,000 = kWh per day, × 30.4 for a month, × your rate.
At 5,000 W for 3.5 hours: 5,000 × 3.5 = 17,500 watt-hours, or 17.5 kWh per day. Times 30.4 gives 532 kWh per month. At 18.44 cents per kWh that is 532 × $0.1844 = about $98.10 for a heating month, or roughly $3.23 a day.
Now the same hours on different technology, which is where the money is. A 3,000 W heat pump: 10.5 kWh a day, 319.2 kWh a month, about $58.86. A 15,000 W resistance furnace: 52.5 kWh a day, 1,596 kWh a month, about $294.30. A 20,000 W furnace: 70 kWh a day, 2,128 kWh a month, about $392.40. Same house, same comfort, same thermostat setting — a difference of over $300 a month decided entirely by what is in the closet.
Standby is real but minor: about 20 W for controls and crankcase heaters, roughly 14.6 kWh a month, about $2.69.
Do not annualise a January figure. EIA's measured 2,484 kWh a year corresponds to about four and a half months at the rate above, not twelve — about $458 a year at the average rate. Multiplying the peak month by twelve overstates it by more than double. And rates swing the total hard: $63.84 a month at 12 cents per kWh, $159.60 at 30 cents. Get your real number from the kWh cost calculator and check the full bill with the electricity bill calculator.
What makes electric heating vary so much
This is the widest range in household energy, and the variables stack rather than average out.
- Technology. Heat pump versus resistance is the whole ballgame — three to five times, before anything else is considered.
- Outdoor temperature. A heat pump's efficiency falls as the outdoor air it is harvesting gets colder, so the same thermostat setting costs more per hour in January than in November. Cold-climate models hold their output far lower than older equipment did.
- Balance point and strip staging. The temperature at which backup strips start helping is set at installation, and a badly configured thermostat can bring them on when the compressor could have coped alone. This is a common and expensive misconfiguration.
- Envelope. Insulation, air sealing and window quality determine how fast the heat you paid for leaves. A leaky house does not merely cost more; it drives a heat pump into its strips more often.
- Sizing and ductwork. Undersized equipment leans on backup heat. Ducts running through an unconditioned attic or crawlspace lose heat before it arrives.
- Setpoint and setback strategy. Discussed below, because with a heat pump the usual advice inverts.
House size matters less than any of these. A well-built large house on a heat pump can easily cost less to heat than a small, leaky one on resistance strips.
Whether it is worth doing anything about
More than any other appliance in the house, yes — this is where the money is in an all-electric home, and two of the fixes are free.
First, never use "Emergency Heat" as a comfort setting. It exists for one purpose: running the house when the compressor has failed. Selecting it locks out the heat pump and runs pure resistance strips, converting a $98 month into something several times larger. If someone in the household switched it on during a cold snap and left it, that alone explains the bill.
Second, avoid deep overnight setbacks. With a gas furnace, dropping the thermostat 8°F at night is sound advice. With a heat pump it usually backfires: recovering 6 to 8°F in the morning is exactly the kind of large, fast demand that triggers the auxiliary strips, and the strips burn more in an hour than the setback saved overnight. Small, gradual setpoint changes — two degrees, with a slow recovery, or a thermostat with genuine adaptive recovery — are the right technique.
After that, the envelope. Air sealing and attic insulation reduce both the hours the system runs and the frequency with which it needs backup heat, and unlike equipment changes they never wear out.
Replacing a resistance furnace with a heat pump is one of the few appliance upgrades that genuinely pays back, because the running cost falls by a factor of three or more every hour of every winter. Replacing a working heat pump with a newer heat pump is a much slower proposition.
How it compares with everything else in the house
At 532 kWh in a heating month, electric heating is in the same weight class as central air conditioning at 638 kWh, and those two between them define what an all-electric home's bill looks like. Everything else is detail. A refrigerator at 36.5 kWh is about 7% of it. An electric clothes dryer at 54.7 kWh is about 10%. A dehumidifier at 152 kWh — itself a substantial load — is under a third.
If the house runs resistance strips instead, at 1,596 kWh for a 15,000 W system, heating alone can exceed everything else in the house combined by a wide margin. That is the situation in which people describe their winter bill as unbelievable, and the bill is generally accurate.
The comparison also explains why a heat pump's summer bill looks modest next to its winter bill even though it is the same hardware: in cooling mode it never falls back to resistance strips, because there is no such thing as backup air conditioning.
Two practical steps follow. Check your bill for the months either side of the coldest one — if the jump is far larger than the temperature difference justifies, suspect auxiliary heat rather than usage. And if you are on a time-of-use plan, morning recovery lands in the expensive window; see what a time-of-use rate is. To compare your own equipment against the rest of the house, use the appliance energy cost calculator.
Frequently asked questions
How many watts does an electric furnace use?
An electric resistance furnace draws 10,000 to 25,000 watts of strip elements to heat a typical house — the widest draw of any household appliance. An air-source heat pump doing the same job draws roughly 3,000 to 5,000 watts, because it moves heat from outdoor air rather than creating it. Both are called electric heat and both live in the same closet, but the resistance furnace uses three to five times the electricity for identical comfort. If you do not know which you have, look for an outdoor unit that runs in winter: that is a heat pump.
How much does a heat pump cost to run per month?
About $98.10 in a heating month at the US average rate of 18.44 cents per kWh. The working: 5,000 watts for 3.5 hours a day is 17.5 kWh, which over a 30.4-day month is 532 kWh, which at $0.1844 per kWh is $98.10. A more efficient 3,000-watt system on the same hours is about $58.86. Do not multiply by twelve — EIA measured 2,484 kWh a year for electric space heating per household using it, about four and a half months at this rate, or roughly $458 a year.
Why is my electric bill so high with a heat pump in winter?
Almost always auxiliary resistance heat. A heat pump contains backup strip elements that energise when it is very cold outside, when the thermostat demands a large temperature rise quickly, or when "Emergency Heat" is selected. Those strips draw three to five times what the compressor does, so a month in which they ran often costs several times a normal month with no change in behaviour. Check whether Emergency Heat was switched on, watch for the auxiliary heat indicator on the thermostat, and replace deep overnight setbacks with small ones — a 6 to 8°F morning recovery is exactly what triggers the strips.
Should I use Emergency Heat on my heat pump?
Only when the heat pump itself has failed. Emergency Heat locks out the compressor and runs pure electric resistance strips, which draw 10,000 to 25,000 watts against the compressor's 3,000 to 5,000. Using it because the house feels cold, or because someone assumed it heats faster, multiplies the heating portion of your bill several times over for as long as it stays selected. If the house is not reaching temperature, the fix is a service call, a filter change, or a thermostat configured with the correct balance point — not the emergency setting.