Cheapest way to heat one room in the UK: oil radiator vs fan heater vs convector

Updated 26 October 2026 · Prices worked out at UK electricity rates

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If you only use one or two rooms in the evening, heating just those rooms can cost less than running the central heating for the whole house. But the type of heater you pick changes how comfortable it feels and how much you spend.

Short answer: all plug-in electric heaters turn electricity into heat at the same efficiency. A 2 kW heater costs about 50p an hour at full power whatever the type. What changes is how fast it heats, how long it stays warm and whether it has a good thermostat. For most rooms, an oil-filled radiator with a thermostat is the best balance. For warming yourself fast for short spells, a small fan heater or a heated throw is cheapest.

Running costs

We use 25p per kWh, close to the current UK price cap.

Heater	Typical power	Cost per hour at full power
Heated throw	100 to 160 W	2.5p to 4p
Oil-filled radiator	1.5 to 2.5 kW	38p to 63p
Fan heater	1 to 2 kW	25p to 50p
Convector heater	2 kW	50p
Halogen heater	0.4 to 1.2 kW	10p to 30p

With a thermostat, a heater only runs at full power until the room reaches temperature, then cycles on and off. In a well-insulated room the real cost per hour can be half the figure above.

Which type for which room

Living room or bedroom used for hours: oil-filled radiator. It heats slowly but evenly and stays warm after it cycles off, so it feels comfortable and is quiet.
Bathroom or a quick blast of heat: fan heater (one rated for bathrooms if used there). Heats the air within minutes.
Sitting still at a desk or on the sofa: heated throw or a small halogen heater pointed at you. You warm the person, not the whole room.
Home office all day: oil radiator on a thermostat plus a heated throw on your lap.

Is it really cheaper than gas central heating?

Gas costs much less per kWh than electricity, roughly a quarter of the price. So per unit of heat, a gas boiler is cheaper. Electric heaters only save money when they let you leave the rest of the house unheated. If you heat the whole house anyway, a plug-in heater just adds to the bill.

Features worth paying for

An accurate digital thermostat, not just a dial.
A 24 hour or 7 day timer.
Tip-over and overheat protection.
For oil radiators: 7 to 11 fins for a typical bedroom or living room.

Where to buy (prices change often, so check the current price):

Safety

Plug heaters straight into a wall socket, never into an extension lead. Keep them a metre from curtains, beds and furniture, and never cover them or dry clothes on them.