United Kingdom Heating
How much does it cost to run an oil filled radiator?
An oil-filled radiator is a resistance heater with a thermal reservoir. It costs exactly what its wattage says while the element is on, but the oil stays warm after the element switches off, so on a thermostat it spends more of the hour idle than a fan heater does.
A 2 kW oil filled radiator costs about 32p an hour to run in Great Britain at 26.32 pence per kWh. Running it 8 hours a day cycling 60% of the time comes to about £2.53 a day, £76.91 a month and £922.88 a year.
- Price: Ofgem cap, Oct to Dec 2026
- Wattage range with its source
- Checked 26 October 2026
Uses 9.6 kWh a day, 292 kWh a month, at 26.32 pence per kWh (Great Britain (price cap average)).
The dial places the daily cost between a 50 watt fan and a 4.5 kW water heater on 2.5 hours a day.
A 2 kW oil filled radiator costs about 32p an hour to run in Great Britain at 26.32 pence per kWh. Running it 8 hours a day cycling 60% of the time comes to about £2.53 a day, £76.91 a month and £922.88 a year.
What this assumes
The default is a 2 kW oil filled radiator running 8 hours a day, drawing full power 60% of the time it is switched on (the rest of the time a thermostat or sensor has it idle). Published typical ratings run from 1,000 to 2,500 watts. Your label or manual gives the exact figure, and the calculator takes it.
The price is the Ofgem price cap unit rate for 1 October to 31 December 2026, average for England, Scotland and Wales, paying by Direct Debit. The cap for 1 January to 31 March 2027 is announced in late November 2026. A fixed tariff, a time-of-use plan or a different payment method changes the rate, which is why the rate field is editable.
Cost by wattage and hours at the price cap rate
At 26.32p per kWh, running flat out. Multiply by the share of the time your thermostat keeps the element on.
| Power | 1 hour | 8 hours | 24 hours | A week at 8 hours a day |
|---|---|---|---|---|
| 1 kW | 26p | £2.11 | £6.32 | £14.74 |
| 2 kW | 53p | £4.21 | £12.63 | £29.48 |
| 2.5 kW | 66p | £5.26 | £15.79 | £36.85 |
How an oil filled radiator uses electricity
The oil is never used up and never needs topping up. It is only a heat store that smooths the on-off cycling of the thermostat.
Because the radiator keeps giving off heat with the element off, a thermostat-controlled unit in a closed room typically draws power about 60% of the time it is switched on. That is the duty assumed here.
They are slow to warm a cold room. If you need heat in minutes, a fan heater is better, then switch to the radiator to hold the temperature.
Ways to cut the cost
- Choose the lowest power setting that holds the room at the temperature you want.
- Keep it away from curtains and furniture so the air can circulate.
- Use the built-in timer or a plug-in one so it is not heating an empty room.
Questions people ask
Are oil-filled radiators cheaper to run than fan heaters?
Per hour at full power, no, the cost is set by the wattage. In practice they often cost less in a closed room because the thermal mass lets the thermostat switch the element off for longer stretches.
Can I leave an oil-filled radiator on all night?
They are designed for long unattended running and most have tip-over switches and overheat cut-outs, but an eight hour night on a 1,500 watt unit at 60% duty is still about 7 kWh. Use the thermostat on a low setting.
Other heating costs
More in the UK
Sources
The electricity price on this page is read from the data file that also lists the release it came from. The wattage range is a published typical range, not a measurement of your appliance.