Cost to run a space heater per hour, day and month
What a 1,500 W space heater costs
At 17 cents a kilowatt hour, a 1,500 W space heater costs 25.5 cents an hour while it is drawing power. 4 hours a day with 50 percent average draw is 3.00 kWh a day, $15.30 a month and $186.15 a year. Change any of those three numbers in the calculator and the answer moves with them, because there is nothing else in the sum.
The label figure is 1500 watts. That is what the device draws while it is working, not what it draws around the clock.
| Hours of use a day | Energy a day | Cost a month | Cost a year |
|---|---|---|---|
| 1 h | 0.75 kWh | $3.83 | $46.54 |
| 2 h | 1.50 kWh | $7.65 | $93.08 |
| 4 h | 3.00 kWh | $15.30 | $186.15 |
| 8 h | 6.00 kWh | $30.60 | $372.30 |
What changes the number
- Most 1,500 W heaters have a low and high setting. Low is usually 750 to 1,000 W, so the cheap setting saves less than people assume and the high setting is the number on the box.
- A heater with its own thermostat does not draw full power continuously. Half the time is a fair default for a room held at one temperature; a cold room with a door open runs closer to full time.
- Heat output is fixed by the wattage, so a 1,500 W heater from a discount store heats exactly as much as a 1,500 W heater with a famous badge. The difference is noise, controls and how the heat is spread around the room.
Find your own wattage
The wattage is stamped on the label on the back or underside. If the label only gives amps, multiply amps by 120 volts to get watts in North America.
What this does not include
It assumes the room loses heat at a normal rate. A single-glazed room with an uninsulated wall can run the heater at full power for the whole session, which doubles or triples the monthly figure.
Check it against your own numbers
The [running cost calculator](../index.html?device=space-heater) opens with this device already selected and its wattage filled in. Replace the wattage with your own reading, set the hours you actually use, and the monthly and yearly figures update in place.
Related: [An electric blanket](../electric-blanket/index.html), [A dehumidifier](../dehumidifier/index.html), [A window air conditioner](../window-ac/index.html).