How Much It Costs to Run a Space Heater All Winter (2024)

TL;DR: A typical 1,500-watt space heater costs about $0.24 an hour to run at the national average electric rate of 16.7 cents per kWh. Used 8 hours a day for four winter months, that's roughly $230. Run it around the clock in one room instead of heating the whole house, and you can still come out ahead of a furnace, but only if you're heating one room, not several.

_Last reviewed: July 2026 · 6 min read_

You bought the space heater to cut your gas bill, but now you're staring at the electric bill wondering if you made things worse. The math isn't complicated once you know your heater's wattage and your local electric rate, and it usually settles the argument fast.

Okoniq Property Hub lets you log utility bills alongside appliance notes, so you can compare what a space heater actually adds to your electric costs month over month instead of guessing.

How much does a space heater cost per hour to run?

A standard 1,500-watt space heater costs about $0.24 an hour at the U.S. average residential rate of 16.7 cents per kilowatt-hour. Wattage divided by 1,000, multiplied by your rate, gives you the hourly cost: 1.5 kWh × $0.167 = roughly $0.25.

Rates vary a lot by state. Hawaii runs closer to 40 cents per kWh, which puts the same heater at $0.60 an hour. Parts of the Pacific Northwest and the South sit closer to 11-12 cents, dropping the hourly cost under $0.20. Check your last bill's "price per kWh" line rather than guessing, since the national average can be off by 30% or more depending on where you live.

Smaller ceramic heaters (750-1,000 watts) run about $0.12-$0.17 an hour. Larger 1,500-watt models, the most common size sold at hardware stores, top out most residential circuits and are what most cost estimates assume.

How much does it cost to run a space heater all winter?

Running a 1,500-watt heater 8 hours a day for a 120-day winter costs about $230 at the national average rate. That's $1.92 a day, multiplied out over four months of use, which is a realistic pattern for someone heating a home office or bedroom during waking hours only.

Leave it running 24 hours a day for the same 120 days and the total jumps to about $691. That's the number people don't expect, because a heater left on overnight in a bedroom or left running in an unoccupied room adds up fast without anyone noticing until the bill arrives. This is exactly the kind of quiet cost covered in 5 appliances quietly running up your electric bill, and space heaters are usually the biggest single line item on that list.

| Usage pattern | Hours/day | Daily cost | 120-day total | |---|---|---|---| | Daytime only | 8 | $1.92 | ~$230 | | Evenings + overnight | 16 | $3.84 | ~$461 | | Continuous | 24 | $5.76 | ~$691 |

Is a space heater cheaper than running the furnace?

A space heater is usually cheaper than a furnace only if you're heating one room and keeping the rest of the house cooler. Electric resistance heat (which is what every space heater uses) is one of the most expensive ways to generate heat per BTU, but it's efficient at the point of use because none of the heat escapes through ductwork or gets wasted heating rooms nobody's in.

If you're supplementing a thermostat set at 62°F with a space heater in one occupied room, you can save real money versus running a furnace to keep the whole house at 68°F. If you're running space heaters in three or four rooms because the furnace can't keep up, you're likely spending more than you would fixing the actual heating problem. A failing furnace, bad ductwork, or poor attic insulation are common reasons homes feel cold enough to need heater backup, and it's worth ruling those out before assuming the heater is saving you money.

Are space heaters safe to run for hours at a time?

Yes, for UL-listed models with tip-over and overheat shutoff, but the outlet and circuit matter more than the heater itself. Space heaters draw 12-15 amps continuously, which is close to the 15-amp limit on most standard household circuits and can trip breakers or overheat older wiring if anything else is plugged into the same outlet.

Homes with two-prong outlets or older wiring are more likely to have circuits that weren't built for a steady 1,500-watt draw. If your outlets predate 1970 or you're not sure what's behind the wall, it's worth reading 2-prong vs 3-prong outlets: how to upgrade safely before running a heater for hours at a stretch. Homes still on knob-and-tube wiring should avoid space heaters on those circuits entirely, since that wiring wasn't rated for sustained modern loads.

If you're running heaters in multiple rooms regularly, it's also worth confirming your panel has the capacity. 100 vs 200 amp service covers how to tell if your electrical service is undersized for how much you're actually running in winter.

FAQ

What size space heater do I need for a 200 sq ft room?

A 1,500-watt heater is generally enough for a 200 sq ft room with normal ceiling height and reasonable insulation. Larger or poorly insulated rooms may need supplemental heat or a higher-wattage unit closer to 2,000-2,500 watts.

Does a space heater use more electricity than a space heater with a thermostat setting?

A heater with a thermostat cycles on and off once it reaches target temperature, which typically cuts run time by 30-50% compared to a heater left on constantly at full output. That difference alone can turn a $690 continuous-use month into something closer to $350-$400.

Can I run a space heater on an extension cord?

It's not recommended. Most extension cords aren't rated for the 12-15 amp draw of a 1,500-watt heater and can overheat, which is the leading cause of space-heater-related house fires. Plug directly into a wall outlet whenever possible.

How do I calculate the exact cost for my specific heater?

Take the wattage listed on the heater (usually on a sticker on the back), divide by 1,000, then multiply by your electric rate per kWh and by hours used. A 1,000-watt heater run 6 hours a day at 15 cents per kWh costs $0.90 a day, or about $108 over a 120-day winter.

Is it cheaper to heat one room with a space heater or heat the whole house?

Heating one occupied room with a space heater while the thermostat runs a few degrees cooler is usually cheaper than heating the whole house to the same temperature. The savings disappear once you're running heaters in more than one or two rooms at a time.

This is educational information, not financial advice. Check your utility's actual rate per kWh and talk to a licensed electrician if you're unsure whether your wiring or panel can handle sustained space heater use.