2kW for 5 hours, heating all the time
2 kW × 5 h × 100% × 26.32p = 263.20p (£2.63) a day. That is £18.42 a week and £80.06 a month.
Home & lifestyle · Energy costs
Oil-filled radiator running cost calculator
At the Ofgem price cap rate of 26.32p per kWh (1 October to 31 December 2026), a 2kW oil-filled radiator costs 52.64p for each hour its element is heating, or £2.63 for 5 hours. Its thermostat switches the element off once the room is warm, so the real cost is often lower.
Enter your radiator’s wattage, the hours it is switched on, the share of that time it is heating and your electricity price for the cost per hour, day, week and month.
52.64pan hour for a 2kW oil-filled radiator heating at 26.32p per kWh£2.63 for 5 hours
Work out your oil-filled radiator’s running cost
Runs in your browser, with no run limit
Running cost
Per hour heating52.64p
Per day£2.63
Per week£18.42
Per month£80.06
Electricity used per day10 kWh
2 kW × 5 h × 100% × 26.32p = 263.20p (£2.63) a day
A week is 7 days; a month is 365 ÷ 12 = 30.42 days. The standing charge is not included (see below).
Per hour
Oil-filled radiator cost per hour by wattage
Cost per hour = power in kW × price per kWh, while the element is heating. At 26.32p per kWh:
| Radiator power | Per hour | 5 hours a day | Month at 5 hours a day | 8 hours a day |
|---|---|---|---|---|
| 1,000W (example) | 26.32p | £1.32 | £40.03 | £2.11 |
| 1,500W (example) | 39.48p | £1.97 | £60.04 | £3.16 |
| 2,000W (CSE typical) | 52.64p | £2.63 | £80.06 | £4.21 |
| 2,500W (example) | 65.80p | £3.29 | £100.07 | £5.26 |
2,000W: Typical rating used by the Centre for Sustainable Energy (2022); yours may differ. Other wattages: Example only: replace with the watts on your appliance’s rating plate or manual.
Thermostat
How the thermostat changes the cost
An oil-filled radiator heats the oil inside it, which keeps giving off heat after the element switches off. The thermostat turns the element off when the room reaches the set temperature and back on when it cools, so it draws full power only part of the time. How much of the time depends on the room, its insulation, the weather and the setting, so this page does not assume a typical figure. For a 2kW radiator switched on for 5 hours:
| Thermostat on-time | Electricity per day | Per day | Per month |
|---|---|---|---|
| 100% (example) | 10 kWh | £2.63 | £80.06 |
| 75% (example) | 7.5 kWh | £1.97 | £60.04 |
| 50% (example) | 5 kWh | £1.32 | £40.03 |
| 25% (example) | 2.5 kWh | £0.66 | £20.01 |
A plug-in energy monitor shows the kWh your radiator actually uses over a day; enter that day’s hours and adjust the on-time until the kWh match.
Step by step
Worked examples
Daily cost = kW × hours switched on × thermostat on-time × price per kWh. Weekly = daily × 7. Monthly = daily × 365 ÷ 12.
2kW for 8 hours, thermostat heating half the time
2 kW × 8 h × 50% × 26.32p = 210.56p (£2.11) a day. That is £14.74 a week and £64.05 a month.
1.5kW (example) for 4 hours
1.5 kW × 4 h × 100% × 26.32p = 157.92p (£1.58) a day. That is £11.05 a week and £48.03 a month.
2.5kW (example) for 3 hours
2.5 kW × 3 h × 100% × 26.32p = 197.40p (£1.97) a day. That is £13.82 a week and £60.04 a month.
1kW (example) for 8 hours
1 kW × 8 h × 100% × 26.32p = 210.56p (£2.11) a day. That is £14.74 a week and £64.05 a month.
Comparison
Is an oil-filled radiator cheaper than a fan heater?
Not at the same wattage and heating time. Every electric heater turns the electricity it uses into heat, so a 2kW oil-filled radiator, convector or fan heater heating for 1 hour uses 2kWh and costs the same. They differ in how quickly they warm a room and how long they stay warm after switching off, which changes how much of the time the thermostat keeps the element on.
For fan heaters and convectors, including 2kW and 3kW models, use the electric heater running cost calculator.
Wattage
How to find your radiator’s wattage
Look on the rating plate (usually on the side or base) or in the manual for a figure in watts (W) or kilowatts (kW). Many oil-filled radiators have two or three power settings: enter the one you use. The Centre for Sustainable Energy uses 2,000W as a typical oil-filled radiator rating (Centre for Sustainable Energy, “What uses watt?” (2022, PDF)), but yours may differ.
Your bill
Standing charge not included
Your electricity bill also has a daily standing charge: an Ofgem GB average of 54.83p a day on Direct Debit for October to December 2026. You pay it whether or not the radiator is on, so it is not a running cost of the radiator and this calculator leaves it out. Only the unit rate (pence per kWh) changes with how long you use it.
Source
Where the 26.32p figure comes from
26.32p per kWh is Ofgem’s GB average Direct Debit electricity unit rate under the energy price cap for 1 October to 31 December 2026. There is no VAT on electricity from 1 October 2026 to 31 March 2027. The cap rate varies by region and payment method, and Economy 7, fixed and prepayment tariffs differ, so use the unit rate on your bill if you know it. The next price cap period starts on 1 January 2027. Source: Ofgem, energy price cap unit rates and standing charges.
Ofgem’s energy price cap unit rates and standing charges page, checked on 23 October 2026, gives for electricity paid by Direct Debit from 1 October to 31 December 2026: “26.32 pence per kWh” and “54.83 pence daily standing charge”.
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Helpful answers
Oil-filled radiator running cost FAQs.
How much does an oil-filled radiator cost to run per hour?
About 52.6p an hour for a 2kW oil-filled radiator while its element is heating, at 26.32p per kWh (the Ofgem price cap average for 1 October to 31 December 2026): 2kW for 1 hour uses 2kWh. A 1.5kW setting costs about 39.5p an hour. When the thermostat switches the element off, the cost is lower in proportion.
How much does a 2kW oil-filled radiator cost per day and per month?
£2.63 a day and £80.06 a month for 5 hours a day with the element heating all the time (10kWh a day at 26.32p per kWh). If the thermostat keeps it heating half the time, it is £1.32 a day and £40.03 a month.
Are oil-filled radiators cheaper to run than other electric heaters?
Not at the same wattage and heating time: 2kW for 1 hour is 2kWh whichever type of electric heater it is. An oil-filled radiator warms up slowly and stays warm after switching off, which changes how often its thermostat switches the element on.
Is the standing charge included?
No. The daily standing charge (an Ofgem GB average of 54.83p a day on Direct Debit for October to December 2026) is paid whether or not the radiator is on, so it is not a running cost of the radiator.