How Much Does a Space Heater Cost to Run?

The cost is the watts, times the hours it runs, times your price per kWh. Enter your heater below, then read how to lower it.

Last reviewed November 3, 2026. Written by the Team of Housenergy Calculator.

Sample numbers only, to show how it works. Replace them with yours.

Your state and prices

State

Fills both prices with the 2024 state averages (EIA). Replace them with your bills.

Electricity price per kWh (dollars)

On your electric bill, in dollars per kWh.

Gas price per therm (dollars)

Only used for the comparison with a gas furnace.

Your space heater

Heater power (watts)

On the label or the box. If it lists amps and volts, multiply them.

Hours a day it runs

Hours at full power. A heater with a thermostat cycles off, so use the hours it is actually heating.

Days a year you use it

Count only the days you run it.

Compare with other ways to make the same heat

Gas furnace AFUE (percent)Optional

Starts at the ENERGY STAR minimum for the South. Use yours.

Heat pump HSPF2Optional

Starts at the ENERGY STAR minimum for split systems. Use yours.

Enter the watts of the heater (it is on the label or the box, often 1,500).

This is an estimate, not a professional calculation. See the disclaimer and the methodology.

The formula in one line

Cost per hour = watts ÷ 1,000 × price per kWh. A 1,500 W heater at the U.S. average of 16.5 cents per kWh (2024) costs $0.25 an hour. Run 8 hours a day for 30 days and it uses 360 kWh, which costs $59. The heater and hours are assumed for this example.

Power against hours for 30 days

The table shows 30 days of use at $0.1648 per kWh. The wattages and hours are examples; find the wattage on your heater and use the calculator for your own.

Cost of 30 days of use by heater power and hours a day, at 16.5 cents per kWh (assumed values)
Heater power	2 hours a day	4 hours a day	8 hours a day
600 W	$6	$12	$24
1,000 W	$10	$20	$40
1,500 W	$15	$30	$59

Why the label power is a ceiling

The wattage on the label is what the heater draws at its highest setting. On a lower setting, or once the thermostat switches it off because the room is warm, it draws less. The hours that matter are the hours it is actually heating. A watt meter plugged in for a day shows your real use.

How to bring the cost down

Heat the room you are in and close the door, instead of the whole home.
Use a thermostat or timer so the heater is not on when nobody is there.
Lower the power setting once the room is warm.
Compare with your main heating. The calculator prices the same heat from a gas furnace and a heat pump, so you can see whether turning the central heat down and using a heater is worth it for your prices.

Safety is not in the cost

This guide covers the electricity bill only. Follow the maker's instructions for where to place the heater and what to plug it into, and do not leave it unattended.

Frequently asked questions

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

It depends on how much of the home you heat and the price of your fuels. Electric resistance costs more per unit of heat than a gas furnace or a heat pump in many states, but heating one room can use less total energy. Compare with the calculator.

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

It uses 1.5 kWh each hour, so the cost is 1.5 times your price per kWh. At 16 cents per kWh that is 24 cents an hour.

Does leaving a space heater on all night cost a lot?

Eight hours at full power is 12 kWh for a 1,500 W heater. A thermostat may switch it off for part of the night, so the cost is lower in practice. Enter the hours it really runs.