Quick answer: To keep yourself warm, a heated throw or electric blanket is by far the cheapest: about 2.6p an hour. To heat a whole room, gas central heating is usually cheaper per unit of heat than any plug-in electric heater, because gas costs 7.97p per kWh against 26.32p for electricity under the October to December 2026 price cap.
Cost per hour compared
| Option | Power or heat | Cost per hour | Heats |
|---|---|---|---|
| Heated throw or electric blanket | 100 W | 2.6p | You |
| Gas central heating (one room’s share) | 2 kW of heat | 18p | Room |
| Plug-in electric heater, low setting | 1 kW | 26p | Room |
| Oil-filled radiator or fan heater, high | 2 kW | 53p | Room |
Gas figure: 2 kWh of heat ÷ 0.9 efficiency × 7.97p ≈ 18p an hour. Real costs depend on the room, insulation and how often the thermostat switches the heat off.
When a plug-in heater makes sense
- You need heat in one small room for a short time and the rest of the house can stay cool, with the central heating turned down.
- Your home has no gas and no heat pump.
- You use a heater with a thermostat and timer, so it only runs when needed.
Every plug-in electric heater turns electricity into heat at the same rate per watt; an oil-filled radiator is not “more efficient” than a fan heater, but it holds heat and may cycle off more often. See electric heater running costs.
Make any heating cheaper
- Close the door and block draughts.
- Close curtains at dusk.
- Use radiator valves to keep unused rooms cooler.
- Lower the combi boiler flow temperature (see how to lower UK energy bills).
- Keep the rooms you use at a safe temperature: the UK Health Security Agency advises at least 18°C in cold weather.
Safety
Plug heaters directly into a wall socket, keep them a metre from bedding and curtains, never cover them, and never use outdoor gas heaters or barbecues indoors.
A real example: one room, one evening
Imagine you sit in the living room from 6pm to 11pm (5 hours) and the rest of the house can stay cool.
- Gas central heating heating the whole house to 20°C: a typical semi-detached home might burn around 3 kWh of gas an hour in cold weather once it is warm, about £1.20 for the evening (15 kWh of gas at 7.97p).
- A 2 kW plug-in heater running about two-thirds of the time on its thermostat: about 6.7 kWh, roughly £1.76.
- A heated throw at 100 W for 5 hours: 0.5 kWh, roughly 13p.
So heating just one room with a plug-in heater can cost more than heating the whole house with gas, because electricity costs about three times as much per kWh. A heated throw costs a fraction of either. If you only use one room and can switch the radiators in the other rooms down, gas central heating with thermostatic radiator valves is usually the best balance of cost and comfort.
What makes a room cheaper to heat
- Size: a small room with the door closed needs far less energy than an open-plan space.
- Draughts: self-adhesive draught strips and a draught excluder under the door are cheap and effective.
- Windows: thick curtains closed at dusk reduce heat loss through single or older double glazing.
- Radiators: do not block them with furniture or long curtains, and bleed them if the top is cold.
- Floors: a rug on bare floorboards makes the room feel warmer at the same temperature.
More questions readers ask
Is it cheaper to heat one room with electric than the whole house with gas?
Sometimes. Electricity costs about three times as much per kWh as gas, so a plug-in heater only wins if it lets you keep most of the house much cooler for long periods.
Do I still pay the standing charge if I use less?
Yes. The standing charges (54.83p a day for electricity and 29.68p for gas under the current cap) are paid whatever you use, so they are not affected by how you heat.
Sources
- Ofgem, Energy price cap.
- UK Health Security Agency, cold weather health guidance.