How Much Does It Cost to Run a Space Heater?

Most plug-in space heaters sold in the US and Canada top out at 1,500 W, the safe limit for a standard 120 V, 15 A outlet. In the UK, Europe and other 230 V countries, fan and convector heaters of 2,000–3,000 W are common, so check the label: a 2,000 W heater costs a third more per hour than a 1,500 W one.

On a low setting (often 600–900 W) the cost per hour drops by about half, but the heater may need to run longer to keep the room warm.

Heaters with a thermostat switch the element off once the room reaches the set temperature, and back on as it cools. In a small, well-insulated room the element may run for only part of each hour, so your real cost can be well below the full-power figure.

The full-power figure is still the right one to plan with for the coldest days, or for a draughty room where the heater rarely switches off.

Every electric resistance heater turns all the electricity it uses into heat, so no space heater is more "efficient" than another of the same wattage. What changes the cost is how much power it draws and for how long.

Heating only the room you're in can cost less than heating the whole house. Heating a whole home with space heaters usually costs more than a heat pump, which delivers two to four units of heat for each unit of electricity, and often more than gas, depending on local prices.

Ranges are typical for heaters on sale in 2026. Your heater's exact rating is on its label; use that number in the calculator.

• Heat only the room you're in, and keep its doors closed.
• Use the thermostat and a timer so the heater isn't running flat out in a room that's already warm.
• Warm the room up on high, then switch to low.
• For one person sitting still, an electric blanket or heated throw usually uses under 200 W, a fraction of a space heater.
• Seal draughts around windows and doors. A heater in a leaky room switches off far less often.

• Electric blanket
• Heat pump
• Kotatsu
• Oil-filled radiator
• Bill analyzer