Published 14th October 2026
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A heated throw or electric blanket warms you rather than the room, which is why it costs a fraction of what a heater does. This article works out what one costs to run at the current price cap, compares it with heating the room, and covers what to look for when buying and using one.
The price used in the sums
Under the Ofgem price cap for 1 October to 31 December 2026, electricity on a standard variable tariff paid by direct debit averages 26.32p per kWh across Great Britain. The standing charge is 54.83p a day. Ofgem states that these electricity figures do not include VAT, because the government has removed VAT from electricity bills from 1 October 2026 to 31 March 2027.
Your own rate may differ. Fixed deals sit outside the cap, and rates vary by region, payment method and tariff type, including Economy 7 and prepayment. Check your bill, then put your own figure into the calculator, which will redo every sum below for you.
The formula
Running cost is wattage divided by 1,000, multiplied by the hours used, multiplied by the unit rate. The wattage is printed on the label or in the instructions. Throws and blankets vary, and the figure on the label is the maximum draw, usually on the highest heat setting.
Here are three examples, all at 26.32p per kWh. They are worked examples using round wattages, not measurements of any particular product.
- A 100W heated throw on the sofa for 4 hours. 100W is 0.1 kW, so 4 hours uses 0.4 kWh. At 26.32p that is about 10.5p for the evening.
- A 60W electric blanket on for 8 hours. 0.06 kW over 8 hours is 0.48 kWh, which comes to about 12.6p.
- A 2,000W fan or oil-filled heater for the same 4 hours. 2 kW over 4 hours is 8 kWh, or about £2.11.
The heater costs about 20 times as much per hour as the 100W throw. That is the whole argument for a throw: if you are sitting still in one place, warming yourself is cheaper than warming the room. The heater figure assumes it runs flat out, and a thermostat will cut that, but the gap stays wide.
What a winter adds up to
Say you use a 100W throw for 4 hours on each of 120 evenings. That is 48 kWh, or about £12.63 across the winter at today's rate. The same hours on a 2,000W heater would be 960 kWh, about £252.67.
Those numbers are upper limits. Many throws and blankets have thermostats or timers that cycle the element, so the real draw is often lower than the label wattage. They also ignore the standing charge, which is 54.83p a day whether or not anything is switched on, so using a throw does not reduce it.
A throw does not heat the house. It works when you are in one place for a while, such as reading, watching television or working at a desk. If the room is cold because of draughts or poor insulation, that is a separate problem, and the electric heater page shows what the alternative costs.
What to look for when buying
A throw is usually sized for one person on a sofa. An underblanket or overblanket is sized to a bed. Pick by use, because the bigger item draws more.
- Controls. Look for a controller with several heat settings and an automatic switch-off timer. A timer stops a throw being left on for hours by accident.
- Washability. Check the instructions on washing, and whether the controller detaches first.
- Wattage on the listing. Retail listings usually state it. Use it in the formula above before you buy, so that the running cost does not come as a surprise.
- Instructions. Read the manufacturer's guidance on age limits, storage and the fuse in the plug before first use.
If you want a heated throw to use on the sofa, Ad a heated throw with timer is a reasonable search to start with. For a bed, Ad an electric underblanket with thermostat covers the overnight case, which is where the next section matters.
Using one safely
Hereford and Worcester Fire and Rescue Service gives the following advice for electric blankets.
- Replace at least every 10 years. Age is a reason to replace one even if it looks fine.
- Test every two years. The service advises regular testing.
- Overnight use. Leave a blanket on all night only if it has thermostatic controls designed for that. Otherwise switch it off and unplug it before getting into bed.
- Check before use. Look for fraying fabric, scorch marks, exposed elements, creasing or folding, soiling, damp patches, damaged or missing tie tapes, worn flex and loose connections. If you are unsure about the condition of a blanket, the advice is to replace it.
- Store it properly. Keep it somewhere dry, flat or loosely rolled so the wires are not damaged, and not under other items.
That page covers electric blankets and does not mention heated throws, so for a throw follow the manufacturer's instructions for age limits and storage, and treat the same checks as a sensible baseline.
Storing a blanket flat or loosely rolled is easier with Ad a large under-bed storage bag, which keeps it clean and away from other items over the summer.
Cheaper ways to use the same idea
The principle is to heat the person rather than the space, so a few other things work the same way.
- A hot water bottle needs a kettle's worth of hot water and no electricity once filled. Ad A hot water bottle with a fleece cover is the usual way to buy one.
- A thick blanket or Ad a fleece blanket for the sofa costs nothing to run at all.
- If you do want to know what a particular throw really draws, Ad a plug-in energy monitor reads the watts directly.
The calculator on this site will work out the running cost of any of these. Enter the wattage, the hours and your own unit rate, and it gives you the monthly and annual figure.