Quick answer: an oil-filled radiator costs about 13p to 66p an hour while heating, depending on its wattage. A 1.5kW radiator on for 6 hours uses up to 9 kWh, which is up to £2.37 a day at 26.32p per kWh. With the thermostat cycling it on and off, the real figure is usually lower.
Oil-Filled Radiator Running Cost Calculator
Results update as you type. Default price: 26.32p/kWh, the Ofgem cap for October to December 2026.
How oil-filled radiator running cost is worked out
Cost = (watts ÷ 1,000) × hours × share of time heating × price per kWh
A 1.5kW radiator on for 6 hours, heating the whole time: 1.5 × 6 = 9 kWh, and 9 × 26.32p = £2.37. If the thermostat keeps it heating 60% of the time, the cost falls to about £1.42. Prices here use 26.32p per kWh, the Ofgem price cap unit rate for electricity paid by direct debit from 1 October to 31 December 2026. Your own rate is on your bill and may be higher or lower, especially on a fixed or Economy 7 tariff, so change it in the calculator.
Running costs by wattage
| Wattage | Per hour (heating) | Per 6-hour day (100%) | Per 6-hour day (60%) | Per winter (26 weeks, 100%) |
|---|---|---|---|---|
| 500W | 13.2p | £0.79 | £0.47 | £143.71 |
| 1kW | 26.3p | £1.58 | £0.95 | £287.41 |
| 1.5kW | 39.5p | £2.37 | £1.42 | £431.12 |
| 2kW | 52.6p | £3.16 | £1.90 | £574.83 |
| 2.5kW | 65.8p | £3.95 | £2.37 | £718.54 |
The 60% column is an example, not a measured figure. How often the thermostat cuts in depends on the room size, insulation, how cold it is outside and the temperature you set. A smart plug with energy monitoring will show your real usage over a few days.
Oil-filled radiator vs gas central heating
From 1 October 2026 the Ofgem cap is 26.32p per kWh for electricity and 7.97p per kWh for gas. A modern gas boiler turns most of that gas into heat, so a unit of heat from gas costs roughly a third of a unit from an electric heater. An oil-filled radiator makes sense for heating one room for a few hours, for example a home office, rather than as a replacement for central heating across the house.
Ways to cut the cost
- Use the thermostat and a lower power setting once the room is warm.
- Heat only the room you are in and keep its door closed.
- Use a timer so it switches on shortly before you need it and off when you leave.
- Choose a size that matches the room. An oversized heater on full power wastes nothing, but an undersized one runs flat out all day.
Worked examples
- Home office: a 1kW radiator on for an 8-hour working day, heating 70% of the time, uses 5.6 kWh. That is about £1.47 a day, or £7.37 for a five-day week.
- Evening living room: a 2kW radiator on full for 3 hours uses 6 kWh, about £1.58 an evening.
Frequently asked questions
How much does an oil-filled radiator cost to run per hour?
At 26.32p per kWh, a 1.5kW oil-filled radiator costs up to 39.5p an hour and a 2kW model up to 52.6p an hour while it is heating.
Are oil-filled radiators cheaper to run than other electric heaters?
Per unit of heat, no. Every plug-in electric heater turns 1 kWh of electricity into about 1 kWh of heat. Oil-filled radiators can still cost less in practice because the warm oil keeps giving off heat after the element switches off, so the thermostat runs the element less often.
Is an oil-filled radiator cheaper than gas central heating?
Usually not per unit of heat. The October to December 2026 cap puts electricity at 26.32p per kWh and gas at 7.97p. It can still be cheaper to heat one room with a radiator than to heat the whole house with gas.
Do oil-filled radiators use a lot of electricity?
They use the wattage on the label while heating, typically 0.5 to 2.5 kW. With the thermostat set, they spend part of the time off, which is why actual use is often lower than wattage × hours.
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