What does an oil-filled radiator cost to run?
Like every plug-in heater it is 100% efficient — so the running cost is set entirely by the wattage and the thermostat, not the type.
Typical model is rated 1,500W
Price cap is 26.11p
31p per hour, 600 hours a year, 720 kWh in total — about £16 a month. Costed over 120 days, not the whole year — this is a winter appliance.
Every electric heater turns one unit of electricity into one unit of heat — a fan heater, a halogen, an oil-filled radiator, all identical on efficiency. What makes the oil-filled type cheaper in practice is the thermostat and thermal mass: it warms up, then cycles off and coasts on the heat stored in the oil, so a 1.5kW heater does not draw 1.5kW the whole time it is on.
That is the saving worth having. Set the thermostat and let it cycle rather than running it flat out; heat the one room you are in with the door shut rather than the whole house; and remember that at three times the price of gas per unit, electric heating only makes sense for a room the central heating cannot reach economically.
The short answer: The cheapest-feeling plug-in heater thanks to its thermostat — but still electric heat, so only for a single room.
What actually helps
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This is the small stuff
Every appliance on this site put together is usually less than a third of a typical energy bill. Heating the house is the rest of it. If the numbers here bothered you, the number that actually matters is what your heating costs — and whether a heat pump would make it better or worse in your particular house.
Work out your heating costOther appliances
Energy figures checked 2026-08-26. Electricity priced at the Ofgem cap for 1 July – 30 September 2026. Your own machine and tariff will differ — put your figures in above.