How Much Does a Space Heater Cost to Run?

The formula

Running cost

watts ÷ 1,000 × hours × price per kWh

The wattage is on the label or in the manual. The Energy Information Administration lists residential electric heaters at 500 to 2,500 watts, with 1,500 watts the most typical size on the market. At 1,500 W the heater draws 1.5 kW, so 8 hours on high is 12 kWh. The kW vs kWh guide explains why power times time gives energy, and the power converter switches between watts, kW and Btu per hour.

Cost of a 1,500 W heater for 8 hours a day

Your price per kWh is on your bill. Divide the total charge by the kWh used to include delivery charges and taxes. The table assumes the heater runs on high the whole time.

Price per kWh	Per hour	Per day	30 days
10¢	$0.15	$1.20	$36
15¢	$0.23	$1.80	$54
20¢	$0.30	$2.40	$72
25¢	$0.38	$3.00	$90
30¢	$0.45	$3.60	$108
35¢	$0.53	$4.20	$126
40¢	$0.60	$4.80	$144

The Energy Information Administration put the US average residential price at 18.16 cents per kWh in August 2026, up from 17.57 cents a year earlier. At that price the same heater costs $2.18 a day and $65 for 30 days. Over a 120-day heating season that is $262. Prices differ a lot by state, so use your own rate in the electricity cost calculator for an exact figure.

Low, high and the thermostat

The cost follows the watts actually drawn. Many heaters have a low setting with a lower wattage on the label, and many have a thermostat that switches the element off once the room reaches the set temperature. The table shows 8 hours a day at 18.16 cents for an example heater whose low setting is 750 W. "On half the time" stands for a thermostat that keeps the element off for half of those hours; your real share depends on the room, the insulation and the weather.

Setting	kWh a day	Per day	30 days
High, 1,500 W, running nonstop	12	$2.18	$65
High, thermostat on half the time	6	$1.09	$33
Low, 750 W, running nonstop	6	$1.09	$33
Low, 750 W, on half the time	3	$0.54	$16

A plug-in energy meter gives the real figure: plug the heater in through it for a few days and read the kWh. That captures thermostat cycling better than any estimate.

Why every electric heater is equally efficient

The Energy Information Administration says electric resistance heating is considered 100 percent energy efficient: all the electricity going in is converted to heat. That holds for every resistance heater, whatever the housing: oil-filled, ceramic, fan or panel. A 1,500 W model of any type turns 1.5 kWh into 1.5 kWh of heat every hour on high, which is 5,118 Btu per hour, since 1 kWh is 3,412 Btu.

Heater watts	Heat output
500 W	1,706 Btu/h
750 W	2,559 Btu/h
1,000 W	3,412 Btu/h
1,500 W	5,118 Btu/h

So a higher price tag buys features, such as a better thermostat, a fan that spreads heat, quieter running or a tip-over switch, not more heat per kWh. Claims that one resistance heater cuts your bill by making more heat from the same electricity do not fit that rule. What can cut the bill is heating less: one room instead of the whole house, fewer hours, or a lower setting. To size a heater to a room, the BTU calculator estimates the heat a space needs.

A heat pump is different. It pulls heat from the surrounding air, and the Department of Energy gives its coefficient of performance, heat delivered divided by energy put in, as 2 to 4. The comparison is in heat pump vs gas furnace cost.

When a space heater saves money

The Department of Energy describes portable heaters as the option when the main heating system is inadequate or central heating is too costly to install or run. The arithmetic shows when it pays. A heater only saves money if it lets you lower the central thermostat enough to cut more energy than the heater uses. Heating one occupied room with 1.5 kW while the rest of the house is cooler can be cheaper; running a space heater in addition to a full central system usually just adds the heater's cost to the bill. For more ideas, see how to lower your electric bill.

Worked example: a home office for a winter

Say you work from home and heat a small office with a 1,500 W heater from 9 to 5 on weekdays, about 85 days over a winter. On high the whole time that is 12 kWh a day and 1,020 kWh for the winter. At 20 cents per kWh it comes to $204. If the thermostat keeps it on for only half the hours once the room is warm, the cost halves to $102. Set against that whatever you save by turning the central thermostat down for the rest of the house during those hours. You can read that saving from your gas or electric bill by comparing similar weeks, or from the meter if it shows daily use.

Two habits keep the number honest. First, use the price from your own bill, not a national figure, since the gap between states is large. Second, measure instead of guessing: a week with a plug-in meter tells you the real kWh, and the formula above does the rest.

Safety rules from the CPSC

The Consumer Product Safety Commission estimates that portable heaters, including electric space heaters, were involved in an average of about 1,600 fires a year from 2020 to 2022. Its winter tips:

Keep portable heaters at least three feet from drapes, furniture, bedding and other things that can burn.
Plug electric space heaters directly into a wall outlet. Do not use an extension cord or power strip.
Turn heaters off when sleeping.
For fuel-burning portable heaters, never refuel while in use; turn the heater off and let it cool first.

The Department of Energy adds that unvented portable combustion heaters can cause carbon monoxide poisoning if not used properly, and says that because safety is a big concern with space heaters, every home should have a carbon monoxide detector.

Frequently asked questions

How much does a 1,500 watt space heater cost per hour?

A 1,500 W heater uses 1.5 kWh in an hour on high. At the US average residential price of 18.16 cents per kWh in August 2026, that is about $0.27 an hour. At 10 cents it is 15 cents an hour, at 40 cents 60 cents an hour.

Are some electric space heaters more efficient than others?

Not in how much heat they make per kWh. The Energy Information Administration says electric resistance heating is considered 100 percent efficient, because all the electricity going in becomes heat. A 1,500 W heater of any style makes the same heat at full power; differences are in how it spreads that heat and how well its thermostat controls run time.

Is it cheaper to run a space heater or turn up the furnace?

It depends on your fuel price, your furnace or heat pump, and how many rooms you heat. A space heater can cost less when you heat one room and turn the central thermostat down for the rest of the house. Compare the kWh cost here with your gas or heat pump cost per unit of heat before deciding.

Does the low setting save money?

Yes, in proportion to the watts. If the low setting is rated 750 W, it uses half the energy per hour of the 1,500 W high setting. With a thermostat, the heater may also cycle off once the room is warm, which cuts the cost further.

Can I plug a space heater into a power strip?

No. The Consumer Product Safety Commission says to plug electric space heaters directly into a wall outlet and not to use an extension cord or power strip. It also says to keep heaters at least three feet from drapes, furniture and bedding, and to turn them off when sleeping.

Sources

Written by Tobias. Updated November 2, 2026.