The cheapest way to heat a room
The cheapest heat is the kind that warms you rather than the room: a heated throw or electric blanket costs about 1.2p to 4.1p an hour at today's price cap. To warm the room itself, every electric heater turns each unit of electricity into the same amount of heat, so the cheapest is the smallest heater that does the job, run for the shortest time. If you have gas central heating, gas costs 7.97p a kWh against 26.32p for electricity.
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What each costs an hour
Where each figure comes from
| Heater | Power | Per hour | Warms |
|---|---|---|---|
| Heated cushion | 0.023 kWh an hour, measured by the Guardian | 0.6p | You |
| Heated throw | 0.044 to 0.155 kWh an hour, as testers published it | 1.2p to 4.1p | You |
| Electric underblanket | 70 to 120 W, published ratings | 1.8p to 3.2p | Your bed |
| Electric foot warmer | 0.096 kWh an hour, measured by the Guardian | 2.5p | Your feet |
| Under-desk infrared panel | 220 W (Herschel) | 5.8p | Your legs |
| Infrared panel heater | 500 W (Herschel) | 13p | What it faces |
| Halogen heater | 400, 800 or 1,200 W (Warmlite) | 11p, 21p or 32p | What it faces |
| Fan heater or convector heater | 2,000 W (Dimplex) | 53p | The room |
| Oil-filled radiator | 2,500 W at full power (De'Longhi) | 66p | The room |
| Portable gas heater (butane) | 245 g of butane an hour at 3.4 kW (Calor) | 92p | The room |
Our arithmetic: power in kilowatts times 26.32p per kWh, the price cap's average electricity rate for Direct Debit, 1 October to 31 December 2026. Measured figures are testers' meter readings on the highest setting; the rest are makers' ratings, the most the heater draws. Heaters with a thermostat use less once the room is warm. Butane at £56.50 for a 15 kg refill, Calor's suggested price on 4 November 2026, before its volatility surcharge; stockists' prices vary. The price cap now.
Why warming yourself costs so much less
A 2 kW heater has to warm all the air in a room, and the walls and windows lose that heat all the time. A heated throw uses about 2% to 8% as much electricity as a 2 kW heater running flat out, and puts it straight into the space around you. An evening of four hours under a throw costs about 4.6p to 16p; four hours of a 2 kW heater costs about £2.11.
They do different jobs. A throw or blanket keeps you warm in a cool room; it doesn't warm the air, dry the house or keep the pipes from freezing.
Which electric heater is cheapest to run?
Per hour at the same power, none of them. A 2 kW fan heater, a 2 kW convector and a 2 kW oil-filled radiator all cost about 53p an hour flat out, because each turns all the electricity it uses into heat. What differs is how they deliver it:
- Fan heaters warm a small room fast, so they suit short bursts.
- Oil-filled radiators warm up slowly and keep giving off heat after the thermostat cuts out, which suits a room you sit in all evening.
- Halogen and infrared heaters warm what they face rather than the air, so they suit one person in one spot.
A heater with a thermostat and a timer costs less over an evening than one that runs flat out, because it switches off once the room reaches the temperature you set.
Is gas cheaper than electric?
Mains gas is. At the price cap a kWh of gas costs 7.97p and a kWh of electricity 26.32p, so heating with a gas boiler costs well under half as much per unit of heat as an electric heater, even allowing for the boiler's losses.
Bottled gas isn't. Butane holds about 13.7 kWh per kilo (Calor's figure), so at the bottle price above it costs about 27p a kWh, close to the price of electricity. A portable gas heater is useful in a power cut, when electric heaters stop; it isn't a cheap way to heat a room. Portable gas heaters.
What to buy
Lakeland StaySnug faux fur heated throw: Good Housekeeping's highest-scoring heated throw. All the heated throws.
£84.99 at LakelandSearch AmazonSilentnight Comfort Control electric underblanket, double: testers' favourite budget electric blanket. All the electric blankets.
See today's price at Amazon