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Space Heater Cost Calculator

See how much your space heater costs to run per hour, day, month, and winter. Enter the wattage, hours, and your electricity rate for an instant answer.

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How to use the Space Heater Cost Calculator

  1. Pick a common heater size or type the wattage from your heater's label.
  2. Enter how many hours a day you run it.
  3. Enter your electricity rate in cents per kWh from your electric bill. The costs update right away.

How the space heater cost is calculated

The math is simple:

Cost per hour = watts ÷ 1,000 × electricity rate

For example, a 1,500-watt heater at 17 cents per kWh costs 1.5 × $0.17 = about $0.26 an hour.

Heater setting Watts Cost per hour at 17¢ 8 hours a day for 30 days
Low 750 about $0.13 about $31
Medium 1,000 about $0.17 about $41
High 1,500 about $0.26 about $61

What does it cost to run a space heater overnight or 24/7?

Cost grows in a straight line with the hours, so you can scale any row. These figures assume the heater draws its full wattage the whole time, at 17 cents per kWh:

Heater setting Overnight (10 hours) All day (24 hours) 30 days nonstop
Low, 750 watts about $1.28 about $3.06 about $92
Medium, 1,000 watts about $1.70 about $4.08 about $122
High, 1,500 watts about $2.55 about $6.12 about $184

A heater with a working thermostat only draws full power while it heats. Once the room is warm, it switches off, so a heater that runs "all night" is often on for only part of that time. Your own bill depends on your rate, the room size and how cold it is outside. If you want to compare against whole-house heating, use our furnace cost calculator.

Ways to spend less on space heating

  • Heat the room you are in, and lower the main thermostat a few degrees.
  • Use the thermostat or eco mode so the heater cycles off when the room is warm.
  • Close doors to keep warm air in one room.
  • Seal drafts around windows and doors.

Stay safe with space heaters

  • Keep heaters at least 3 feet from anything that can burn, like curtains, bedding, and furniture.
  • Plug heaters straight into a wall outlet, not an extension cord or power strip.
  • Turn heaters off when you leave the room or go to sleep.
  • Choose a model with tip-over and overheat shutoff.
  • Make sure your smoke alarms are working and not chirping.
  • Check what else is on the circuit with the circuit load calculator, because a heater and a few other devices can pass a 15 amp breaker.

If your main heat is not keeping up, check our guide on a furnace blowing cold air before you rely on space heaters.

Frequently asked questions

How much does it cost to run a 1500-watt space heater?

A 1500-watt heater uses 1.5 kWh each hour on high. At 17 cents per kWh, that is about 26 cents an hour, $2.04 for 8 hours, or about $61 a month if you run it 8 hours a day.

How much does it cost to run a space heater 24/7?

A 1500-watt heater that never shuts off uses 36 kWh a day. At 17 cents per kWh that is about $6.12 a day and about $184 for 30 days. A thermostat that cycles the heater off will bring the real bill down.

Is it cheaper to use a space heater or central heat?

Heating one small room with a space heater and turning the thermostat down for the rest of the house can save money. Heating the whole home with several space heaters is usually more expensive than a furnace or heat pump.

Where do I find my electricity rate?

Look on your electric bill for the price per kWh. If your bill has several charges, add the supply and delivery rates together. Many U.S. homes pay somewhere around 15 to 20 cents per kWh.

Does the eco or low setting save money?

Yes. Most heaters use about 750 watts on low, which is half the cost of high. A heater with a thermostat also turns off when the room is warm, which lowers the real cost.

Learn more