How much does it cost to run a space heater?
A 1,500 W space heater costs about 27¢ per hour at full power at the US average electricity price, and a 2 kW heater about 53p per hour under the UK price cap. Calculator and examples.
- Per hour of use
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- Per day
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- Per month
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- Annual consumption
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Results are indicative estimates based on the values you enter. Always check your appliance labels, your tariff and the manufacturer’s data.
- US (18.31¢/kWh, EIA July 2026): about 27¢ per hour for a 1,500 W heater on high, about 14¢ on a 750 W low setting.
- UK (26.32p/kWh, Oct–Dec 2026 cap): about 53p per hour for a 2 kW heater, about 39p for 1.5 kW.
- With a thermostat, the heater cycles off, so real costs are lower than the full-power figure.
- All resistive electric heaters turn 1 kWh of electricity into about 1 kWh of heat, whatever the technology.
The calculator above is preset for a 1,500 W heater used 6 hours a day: adjust the wattage, hours, your price per kWh and the share of time the heater actually runs.
Cost per hour by wattage
A space heater draws its rated wattage while the element is on. Cost per hour at full power:
| Heater power | Energy per hour | US (18.31¢/kWh) | UK (26.32p/kWh) |
|---|---|---|---|
| 500 W | 0.5 kWh | 9¢ | 13p |
| 750 W | 0.75 kWh | 14¢ | 20p |
| 1,500 W | 1.5 kWh | 27¢ | 39p |
| 2,000 W | 2 kWh | 37¢ | 53p |
Most portable heaters sold in the US top out at 1,500 W, with a 750 W low setting, so that they can run on a standard 120 V household outlet. In the UK, 2 kW and 3 kW heaters are common.
Per day and per month
Running a 1,500 W heater on high for 8 hours uses 12 kWh. At the US average price that is about $2.20 per day, or roughly $66 for 30 days. In the UK, a 2 kW heater for 8 hours uses 16 kWh, about £4.21 per day.
These are worst-case figures: they assume the heater never switches off.
The thermostat effect
A heater with a thermostat switches its element off once the room reaches the set temperature, then back on as the room cools. Over an hour it might run 30%, 50% or 80% of the time, depending on:
- how well the room is insulated and how cold it is outside;
- the gap between the set temperature and the outside temperature;
- whether the heater is big enough for the room (an undersized heater runs constantly).
Example: a 1,500 W heater that runs half the time for 8 hours uses 6 kWh, about $1.10 per day in the US. A plug-in energy monitor tells you the real figure for your room.
Are some space heaters more efficient?
Every resistive electric heater (oil-filled radiator, ceramic fan heater, convection panel, infrared heater) converts about 1 kWh of electricity into 1 kWh of heat. Claims of “efficient” space heaters are about how the heat is delivered, not how much heat you get per kWh:
- Infrared and radiant heaters warm people and objects directly, which can feel comfortable at a lower air temperature when you sit close.
- Oil-filled radiators release heat slowly and quietly.
- Fan heaters warm a small room quickly.
The real savings come from heating only the room you are in, for only as long as you need, at the lowest comfortable temperature.
Space heater or central heating?
Heating one room with a space heater can be cheaper than heating the whole house, especially if your central system is old or the rest of the house is unoccupied. But per unit of heat, electricity from a resistive heater is often more expensive than heat from a gas furnace or a heat pump. A heat pump moves heat from outside rather than generating it, delivering several kWh of heat per kWh of electricity, which is why it beats resistive heating on running costs.
Safety first
Follow the manufacturer’s instructions: plug space heaters directly into a wall outlet rather than an extension lead, keep them away from curtains, bedding and furniture, and never leave them running unattended or while you sleep.