Electric blanket or heater: which is right for you and which costs less to run
If you feel the cold on the sofa or in bed, an electric blanket warms the part that matters for about a twentieth of the electricity a heater uses. If you need the whole room warm, a blanket is not enough.
Quick verdict
- Buy a heated throw if… you get cold sitting on the sofa, working from home or reading in the evening, and want to spend as little as possible. It heats you, not the air: about 3 to 4p an hour.
- Go for an electric underblanket if… what you hate is getting into a freezing bed. It sits under the sheet, warms the bed before you get in and switches off when you go to sleep.
- Stick with a heater if… you need the room warm for several people, for getting dressed or for a bathroom. It warms up fast, but costs around 50p an hour at full power.
Heated throw, electric underblanket and heater at a glance
| Heated throw (sofa) | Electric underblanket | Ceramic fan heater | Oil-filled radiator | |
|---|---|---|---|---|
| Typical power | 100–160 W | 60–120 W | 1,500–2,000 W | 1,500–2,500 W |
| Cost per hour (≈ 25p/kWh) | 2.5–4p | 1.5–3p | 38–50p | 25–50p (with thermostat) |
| What it warms | You | The bed | The room | The room |
| Time to feel warm | 5–10 min | 15–30 min before bed | 1–2 min | 20–30 min |
| Price to buy | £30–£70 | £25–£70 | £25–£60 | £45–£110 |
| Washable | Yes, with the control removed | Yes, with the control removed | n/a | n/a |
| Safe to leave on overnight | No (only with auto shut-off) | No: switch off when you get in | Not advised | On a low thermostat |
Indicative UK prices as of November 2026. Running costs use about 25p/kWh, close to the Ofgem price cap; check your own tariff.
What each one really costs to run
Running cost is power times time. A 120 W heated throw left on for an hour uses 0.12 kWh: at 25p/kWh, 3p. A 2,000 W heater uses 2 kWh in that same hour: about 50p.
Three hours on the sofa every evening for a month comes to around £2.70 with the throw and around £45 with the heater flat out. Even if the heater's thermostat halves that, the gap is still tenfold.
Blankets have several heat settings, and hardly anyone needs the top one after the first few minutes. On a middle setting they use even less than the label says.
How warm they keep you, and who
A blanket warms by contact: you feel it straight away, but only where it covers you. Stand up and the room is still cold. That is why it works so well for one person sitting down and so badly for a family coming and going.
A heater warms the air. In a small, closed room you notice it in a couple of minutes; in a large living room or one with draughty windows it takes longer, and the heat leaves as soon as you switch it off.
Using both works well: the heater for ten minutes to take the chill off the room, then the throw to stay cosy for the rest of the evening.
Heated throw, underblanket or overblanket
- Heated throw: goes on top of you, usually fleece or sherpa, and works on the sofa or over the duvet.
- Electric underblanket: a thin cover that goes between the mattress and the fitted sheet. Switch it on before bed, off when you get in.
- Dual-control double or king-size underblankets: one control per side, so each person picks their own setting.
- Heated pads: small, for the back or neck. Good for aches, not a replacement for a blanket.
Safety: what really matters
Modern electric blankets have overheat protection and automatic shut-off. The basic rules still apply:
- Never fold or bunch it up while it is on: the heat builds up in the folds.
- Check the flex and the fabric when you get it out each winter. Scorch marks, exposed wires or hot spots mean it goes in the bin. UK safety advice is to replace a blanket after about ten years.
- Wash it as the label says (usually 30–40 °C, control removed) and make sure it is completely dry before plugging it in.
- Do not use it with babies, or with anyone who cannot switch it off or does not feel heat well (for example, with diabetic neuropathy).
- Keep heaters away from curtains and clothes, plug them straight into the wall and never cover them.
For sleeping, an underblanket switched on a while before bed and off when you get in is both the safest option and the cheapest.
What to look for in an electric blanket
- Auto shut-off: 1 to 3 hours on throws; essential if you might fall asleep.
- Heat settings: between 3 and 9. More is not better, but it lets you fine-tune the running cost.
- Size: 130 × 180 cm covers one person on the sofa; for beds, buy the size of your mattress (single, double, king).
- Fabric: fleece (light and thin) or sherpa (thicker and softer). Sherpa keeps you warm even when it is off.
- Detachable control and machine-washable: if you cannot wash it, it is not worth it.
- A UK plug and a brand with UK support: Dreamland, Silentnight, Beurer or Russell Hobbs.
Where to buy
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Dreamland Intelliheat heated throw
A long-standing UK brand: soft throw with several heat settings and automatic shut-off. Machine-washable.
Beurer HD 75 Cosy heated throw
From a German health brand: 6 settings, switches off after 3 hours, very soft fabric.
Silentnight Comfort Control electric blanket
Popular underblanket with several heat settings and dual controls on the double and king sizes.
Dreamland Intelliheat electric underblanket
Underblanket with sensors that adjust the heat by themselves, in single, double and king.
Ceramic fan heater 2000W with thermostat
To take the chill off a room in minutes. Look for a thermostat and a tip-over switch.
Frequently asked questions
How much does an electric blanket cost to run per month?
Very little. A 120 W blanket used three hours a day uses about 11 kWh a month: roughly £2.70 at 25p/kWh. A 2,000 W heater used the same way can cost over £40.
Can you sleep with an electric blanket on?
It is not advised. Use an underblanket to warm the bed before you get in and switch it off when you do. If you use a throw in bed, make sure it has automatic shut-off.
Are electric blankets dangerous?
A modern blanket in good condition, used flat, is safe: it has overheat protection. The risk is in old, damaged or damp blankets. Check it every winter and replace it if it shows wear, or after about ten years.
Which is warmer, an electric blanket or a heater?
It depends on what you want to warm. A blanket warms you faster and with far less electricity; a heater warms the whole room. For one person on the sofa, the blanket wins.
Can you wash an electric blanket?
Most can be machine-washed at 30–40 °C with the control removed. Check the label and let it dry completely before you plug it back in.