Space Heater Running Cost Calculator
Electric space heaters are cheap to buy but can be expensive to run. This calculator shows the cost per hour, day and heating season.
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Last updated June 30, 2026. Results update automatically as you type.
How it works
Cost per hour = watts ÷ 1000 × rate. Cost per day = cost per hour × hours used. Seasonal cost = cost per day × heating days per year. Electric resistance heaters are 100% efficient at the plug, so wattage directly drives cost — there is no cheaper or more expensive electric heater for the same heat output.
Frequently asked questions
Are space heaters cheap to run?
For heating one small room briefly, yes. For heating a whole home for long periods they are usually expensive compared with a heat pump or central heating.
Do “energy-saving” heaters use less power?
For the same heat output, no — all electric resistance heaters convert electricity to heat at ~100%. Savings come from heating less space for less time, or from using a heat pump instead.
How do I cut the cost?
Heat only occupied rooms, use a timer or thermostat, close doors, and dress warmly. A heat pump is far cheaper per unit of heat for sustained use.
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