If you spend most of a winter evening in one room, heating just that room can cost far less than warming the whole house. The trick is picking the right way to do it, because the popular options are further apart on cost than most people realise. A cheap electric heater running flat out can quietly cost more than the central heating you were trying to avoid, while a heated throw at your feet costs pennies an hour and keeps you just as comfortable. This guide sorts the choices by what they actually cost to run, and by when each one earns its keep.
The short answer. To warm a person rather than a whole room, a heated throw or electric blanket wins on cost, at roughly 3p an hour. To warm a small room properly, a thermostatic oil-filled or panel heater is usually the best value electric option, costing around 15p to 30p an hour once it settles, at an example rate of 26p per kWh. Firing the gas central heating just for one room only makes sense if that room shares warmth with others you also use, or if the room is large. Whatever you choose, a draughty room that leaks heat will make any of them expensive.
Heat the person before you heat the room
The cheapest heat is the heat you do not have to make. A room holds a lot of air and a lot of cold surfaces, and warming all of it to a comfortable temperature takes real energy. Warming only the person in it takes almost none. A heated throw draped over your lap draws around 100 to 120 watts on its highest setting, which at an example 26p per kWh is roughly 3p an hour, and most of the time it sits on a lower setting drawing less. An electric blanket on the bed or a heated cushion works the same way. Sitting under one of these in a jumper, you can keep a room several degrees cooler and never notice, because your skin feels the warmth directly rather than waiting for the air to catch up.
This is not a fringe tactic; it is the single biggest saving on offer here. Where a heater has to pour out a kilowatt or two to lift the temperature of a whole room, a personal heat source uses a tenth of that or less to keep you comfortable. It will not dry the washing or stop the pipes freezing, and it does nothing for anyone the other side of the room, but for one person on a sofa for the evening it is hard to beat. Reach for a heater only when a throw plus a jumper really is not enough, or when more than one person needs warming across a larger space.
The electric heater options, ranked by running cost
When you do need to heat the air, the type of electric heater matters less for how much heat you get and more for how it is controlled. Every plug-in electric heater is close to 100 per cent efficient, so a 2kW heater of any design turns 2kW of electricity into 2kW of heat. What separates them is whether they have a decent thermostat, how quickly they warm a space, and whether the warmth lingers. A heater that runs flat out with no thermostat costs its full rated power every hour; one that cycles on a thermostat only draws power when it needs to, so its average cost is far lower.
| Heater type | Typical power | Cost per hour at full power | Best for |
|---|---|---|---|
| Halogen bar heater | 1.2 kW | ~31p | Instant spot warmth, one person, short bursts |
| Fan heater | 2 kW | ~52p | Warming a small room fast, then switching off |
| Oil-filled radiator | 1.5 kW (thermostatic) | ~39p, less once settled | Steady background warmth in a small room |
| Convector or panel heater | 1.5 to 2 kW (thermostatic) | ~39p to 52p, less once settled | A room you sit in for a while |
| Infrared panel | 0.6 to 1 kW | ~16p to 26p | Warming people and surfaces directly |
Illustrative costs at an example 26p per kWh at full power. A thermostatic heater rarely runs at full power for a whole hour once the room is warm, so the real hourly cost is usually well below these figures. Put your own wattage and rate into the running cost calculator for an exact number.
A few things fall out of that table. The halogen and fan heaters feel cheap because they are cheap to buy, but with no useful thermostat they tend to run at full whack, so a couple of hours a night adds up quickly. The oil-filled radiator is slow to warm up but keeps giving off heat after it switches off, and its thermostat means it idles rather than blazing once the room is comfortable, which makes its average cost lower than the headline suggests. An infrared panel is the odd one out: it warms objects and people in its line of sight rather than the air, so a lower wattage can feel like enough. For a room you settle into for the evening, a thermostatic oil-filled or panel heater usually gives the best comfort per penny.
Where the money really goes: the thermostat, not the badge
It is worth labouring this point because it decides your bill more than the heater you buy. Two 2kW heaters, one with a good thermostat and one without, can differ two or threefold in what they cost over an evening. Without a thermostat, the heater draws its full 2kW every minute it is on, so four hours is 8 kWh, about £2.08 at 26p. With a thermostat set to a sensible temperature, the heater blasts for the first twenty minutes to warm the room, then clicks on and off to hold it, perhaps averaging 0.8kW across the evening. That is a little over 3 kWh, or roughly 85p for the same four hours in the same room. Same heat in the room, less than half the cost, purely because the heater stopped when the job was done.
So the practical rule is to buy or use a heater with a proper thermostat, set it no higher than you need, and let it cycle. If your only heater is a basic fan or halogen model, switch it off yourself once the room is warm and give it short bursts rather than leaving it running. The thermostat setting that keeps you comfortable is almost always lower than the one you would reach for out of habit.
When the central heating still wins
Heating one room electrically is not automatically cheaper than the gas central heating, and the reason comes back to fuel price. A unit of gas costs roughly a quarter of a unit of electricity, so a gas radiator giving off the same heat as an electric heater costs far less to feed. The catch with central heating is that firing the boiler warms water that runs through pipes and often through radiators in rooms you are not using, so some of the gas you pay for ends up warming the hall and the spare bedroom. The heat one room or the whole house guide works through exactly when that trade-off tips.
The rough guide is this. If you can shut down the rest of the house with radiator valves and heat a single radiator, gas often beats an electric heater on cost because the fuel is so much cheaper, even allowing for a little waste in the pipes. If the room is large or you want several rooms warm, central heating is almost always cheaper than running two or three electric heaters. But for a small room, warmed for a short spell, in a house where firing the boiler would also heat pipework and rooms you do not care about, a single thermostatic electric heater can come out ahead. There is no universal winner; it depends on the room, the spell, and how much of the rest of the house the boiler drags along with it. For the underlying cost gap, see gas versus electric heating cost.
A worked example: one room for an evening
Picture a small living room, warmed from about six until ten, four hours, on a cold evening. Compare three ways of doing it, all figures illustrative at 26p per kWh of electricity and roughly 8p per useful kWh of gas heat.
| Method | Rough energy over 4 hours | Illustrative cost |
|---|---|---|
| Heated throw only, one person | ~0.4 kWh electricity | ~10p |
| Thermostatic 1.5kW panel heater | ~3.5 kWh electricity | ~90p |
| 2kW fan heater left running | ~8 kWh electricity | ~£2.08 |
| Single gas radiator, rest of house valved off | ~5 kWh gas heat | ~40p |
Rounded illustrative figures for one small room over four hours. Your own numbers depend on room size, how draughty it is, the temperature you hold, and your unit rates.
The spread is the whole story. The throw is nearly free but only warms the person under it. The single gas radiator is cheap to feed but relies on being able to shut the rest of the house down. The thermostatic panel heater sits in the middle and warms the room properly for one person or two. And the fan heater left running is the dear option, not because fan heaters are wasteful, but because nothing turned it off when the room was warm. If comfort for one is all you need, the throw plus a jumper wins outright; if you want the room itself warm, the choice is between a single gas radiator and a thermostatic electric heater, and which is cheaper depends on how much of the house the boiler would otherwise heat.
Make the room hold its warmth
Whatever you use to make the heat, a leaky room throws money away, because warmth escapes as fast as you make it and the heater or boiler runs longer to keep up. The cheap fixes here pay back faster than any change of heater. Close the curtains at dusk so the glass stops draining warmth into the night; heavy or lined curtains do most, and a thermal curtain more still. Shut the door to the room you are heating so you are not warming the whole house by accident. Block the obvious draughts around the door and window with a few pounds of draught-proofing strip and a door snake along the bottom. None of this costs much, and all of it means your chosen heater reaches a comfortable temperature sooner and switches off sooner, which is where the running cost actually falls.
Putting it together
The cheapest way to heat one room depends on what you are really trying to warm. If it is just you, a heated throw or blanket costs a few pence an hour and beats every heater going. If it is the room, choose a heater with a real thermostat, set it modestly, and let it cycle rather than run flat out, which is what turns a dear evening into a cheap one. Check whether your gas central heating could do the same job for less by heating a single radiator with the rest of the house valved off, since cheap gas often undercuts electric heat. And spend a little on curtains, a closed door and draught strip first, because a room that keeps its warmth makes every heating choice cheaper. For the running cost of any specific heater at your own rate, the appliance running cost calculator does the sum in seconds.
Common questions
What is the cheapest way to heat one room in the UK?
To warm yourself, a heated throw or electric blanket at roughly 3p an hour is the cheapest by far. To warm the room itself, a thermostatic oil-filled or panel heater is usually the best value electric option, and a single gas radiator with the rest of the house valved off is often cheaper still because gas costs about a quarter of electricity per unit.
Is it cheaper to use an electric heater or the central heating for one room?
It depends. Gas is much cheaper per unit, so a single gas radiator often beats an electric heater if you can shut the rest of the house down with radiator valves. But if firing the boiler also warms pipework and rooms you are not using, a thermostatic electric heater in a small room used briefly can work out cheaper.
Which electric heater is cheapest to run?
They are all close to 100 per cent efficient, so the cheapest to run is the one with the best thermostat, because it stops drawing power once the room is warm. A thermostatic oil-filled or panel heater usually costs less over an evening than a fan or halogen heater left running, even at the same wattage.
Do heated throws and blankets really save money?
Yes, when they replace a heater rather than add to it. A heated throw draws around 100 to 120 watts, roughly 3p an hour, against a heater's 1.5 to 2kW. Warming the person under it lets you keep the room cooler, which is where the saving comes from.