How much does a 500W heater cost to run?

What a 500W electric heater costs per hour, per day and per month at the Ofgem price cap, and how to make it cheaper.

Updated: November 2026Electricity: 26.32p/kWh (Ofgem price cap)

Quick answer: a 500W heater costs 13.2p an hour at full power at the price cap (26.32p/kWh). Three hours a day for a month is about £11.84, or around £7.11 if a thermostat switches it off once the room is warm.

500W heater: running cost per hour, day, week and month

Use	Per day	Per week	Per month	Month on thermostat*
1 hour a day	13.2p	92.1p	£3.95	£2.37
2 hours a day	26.3p	£1.84	£7.90	£4.74
3 hours a day	39.5p	£2.76	£11.84	£7.11
5 hours a day	65.8p	£4.61	£19.74	£11.84
8 hours a day	£1.05	£7.37	£31.58	£18.95

At the Ofgem price cap (26.32p/kWh, Direct Debit, national average). * A heater on a thermostat heats about 60 % of the time once the room is warm. Your standing charge (54.83p/day) is paid whether or not you use the heater.

How to work it out yourself

Watts ÷ 1,000 × hours × your unit rate. A 500W heater for 3 hours: 0.5 × 3 = 1.5 kWh, × 26.32p = 39.5p. Your unit rate is on your bill; on Economy 7 it depends on the time of day (see storage heaters and Economy 7).

Every heater, side by side

Power	1 hour	3 hours a day, a month	On a thermostat*
500 W	13.2p	£11.84	£7.11
1 kW	26.3p	£23.69	£14.21
1.5 kW	39.5p	£35.53	£21.32
2 kW	52.6p	£47.38	£28.43
2.5 kW	65.8p	£59.22	£35.53
3 kW	79.0p	£71.06	£42.64

At the Ofgem price cap (26.32p/kWh, Direct Debit, 1 October to 31 December 2026). * A heater on a thermostat is assumed to heat about 60 % of the time once the room is warm.

500W heaters we recommend

Russell Hobbs RHOFR3001W 650W 5 Fin Oil Filled Radiator

Oil filled radiator · 650 W
Small 650 W oil radiator with adjustable thermostat for rooms up to 10 m²: one of the cheapest ways to keep a small room or office warm for hours.
Costs 17.1p an hour at full power.

Check price on Amazon → Read the review

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Want it cheaper? Choose the smallest heater that keeps the room warm, use the thermostat and timer, and close the door. To warm just yourself, a heated throw costs about 3.9p an hour.

Frequently asked questions

How much does a 500W heater cost per hour?

13.2p at full power at the Ofgem price cap (26.32p/kWh).

How much does it cost to run a 500W heater all day?

Eight hours at full power is about £1.05; on a thermostat, closer to 63.2p.

Are some electric heaters more efficient than others?

No: every electric heater turns 1 kWh of electricity into 1 kWh of heat. Running costs depend on the power, how long it is on and its controls (thermostat, timer).

Running costs use the Ofgem energy price cap, 1 October to 31 December 2026: average unit rate for electricity paid by Direct Debit (26.32p/kWh, standing charge 54.83p/day) and gas (7.97p/kWh). National averages; your region and tariff may differ. Prices on Amazon change: check the live price before you buy.