Quick answer: in the UK listings we checked, electric underblankets are rated from about 40W (single) to 100W (super king), and heated throws from 100W to 300W. At the example rate of 26.32p per kWh, a 70W double blanket costs about 1.8p per hour, 14.7p for eight hours or £4.42 for 30 nights at eight hours a night, if it drew its full rated power the whole time. Pre-heating the bed for 30 minutes at 70W costs about 0.9p. Many blankets draw less than their rating once warm, so check the label on your own blanket and measure it if you can.
Electric blanket running-cost calculator
Enter your blanket’s rated power (from its label or controller), how long it is switched on each night and your unit rate. This estimates the extra electricity cost; it does not add the daily standing charge.
Unit rate is pre-filled with Ofgem’s average for 1 October to 31 December 2026 (checked 1 October 2026); replace it with the rate on your bill. Average power: 100% means full rated power the whole time, which is an upper estimate.
Estimated cost per hour: –
Estimated cost per night (8 hours): –
Estimated cost for 30 nights: –
Estimated electricity used for the period: –
Estimate assumes the blanket draws the percentage of its rated power you entered for every hour it is switched on. Many blankets draw less than their rating once warm, and real use depends on the heat setting and room. It is an estimate, not a forecast of your bill. Only leave a blanket on overnight if it is designed for it: follow the manufacturer’s instructions.
Last checked: 11 October 2026. The example unit rate is Ofgem’s average electricity unit rate for a standard variable tariff paid by Direct Debit in England, Scotland and Wales for 1 October to 31 December 2026: 26.32p per kWh. It excludes VAT, which the government has removed from domestic electricity until 31 March 2027. Ofgem’s next price cap announcement is due on 25 November 2026. Your own rate can differ by region, payment method and tariff, so use the one on your bill. See Ofgem’s price cap announcement and our Ofgem price cap explainer → .
How much electricity does an electric blanket use?
An electric blanket’s power is shown in watts (W) on its label, controller or box. Your bill is measured in kilowatt-hours (kWh), and one kWh is the energy used by a 1,000W (1kW) appliance running for one hour. A 70W blanket therefore uses 0.07kWh each hour, and would need about 14 hours to use 1kWh.
The type matters as much as the size:
- Underblankets fit under your bottom sheet, usually with straps.
- Overblankets/ Blankets sit on top of the bed and are the most common type in the listings we checked. Fire services advise never using an underblanket as an overblanket, or the other way round.
- Heated throws are made for sofas or laps and are often rated higher than underblankets.
- Heated pads and shawls are smaller. One UK energy supplier’s guide puts pads at around 100W and shawls at around 120W, so check the label rather than assuming they are lower.
Typical electric blanket wattages in the UK
These are examples from UK retailer listings checked on 11 October 2026. They are not averages.
| Type | Example rated power | Where the example comes from |
|---|---|---|
| Single underblanket | 40W | Silentnight Single Electric Underblanket at Argos |
| Small double blanket | 70W | Slumberdown Warm Hugs Electric Blanket at Argos |
| King blanket | 90W | Silentnight Winter Warmer King at Boots |
| Super king blanket | 100W | Silentnight Winter Warmer Super King at Silentnight |
| Heated throw | 105W | Silentnight Comfort Control heated throw at Silentnight |
| Large heated throw | 300W | Dreamland Intelliheat Faux Fur Warming Throw at Boots |
These are retailer or supplier statements, not readings from a rating label, and different models of the same size can differ. Even brand web copy is not always consistent with product listings: Silentnight’s own single-blanket category page says its electric blankets use 100W to 150W, while UK retailers list a Silentnight single at 40W. When figures conflict, the rating on your own blanket, controller or manual wins.
How to calculate an electric blanket’s running cost
Use this formula:
Cost (£) = watts ÷ 1,000 × hours used × unit rate (£/kWh)
Worked example for a 70W blanket switched on for eight hours at 26.32p per kWh (£0.2632):
70W = 0.07kW → 0.07 × 8 hours = 0.56kWh → 0.56 × £0.2632 = £0.147 (about 14.7p)
For 30 nights at the same eight hours, that is 0.56kWh × 30 = 16.8kWh, which costs about £4.42. This is an estimate, not a forecast of your bill.
Electric blanket cost per hour, night and month
The table assumes the blanket draws its full rated power for every hour shown, at 26.32p/kWh. It shows the extra electricity cost of the blanket, not your whole bill. “30 nights” means 30 nights in a row.
| Rated power | Per hour | 30-minute pre-heat | 8 hours | 30 nights, 30-minute pre-heat | 30 nights at 8 hours |
|---|---|---|---|---|---|
| 40W | 1.1p | 0.5p | 8.4p | 15.8p | £2.53 |
| 70W | 1.8p | 0.9p | 14.7p | 27.6p | £4.42 |
| 90W | 2.4p | 1.2p | 19.0p | 35.5p | £5.69 |
| 100W | 2.6p | 1.3p | 21.1p | 39.5p | £6.32 |
| 150W | 3.9p | 2.0p | 31.6p | 59.2p | £9.48 |
| 300W | 7.9p | 3.9p | 63.2p | £1.18 | £18.95 |
Use the rated power on your own blanket, not these examples. The full-power assumption is an upper estimate, because real use is often lower, as explained next.
Why your real cost may differ
Heat setting. The rating is normally the most the blanket should draw, usually on its highest setting. Supplier-advised figures relayed in Argos product Q&A for Silentnight Comfort Control blankets show how much the setting can matter:
| Heat setting | Single (rated 40W): draw | Single: 8-hour cost | Double (rated 70W): draw | Double: 8-hour cost |
|---|---|---|---|---|
| 1 (lowest) | 12W | 2.5p | 22W | 4.6p |
| 2 | 25W | 5.3p | 44W | 9.3p |
| 3 (highest) | 40W | 8.4p | 70W | 14.7p |
The supplier says the highest-setting figure includes the warm-up stage, and recommends turning down to setting 1 once the blanket has reached temperature. Other brands and models will differ, and we have not confirmed these figures on Silentnight’s own pages.
Measured use can be lower than the label. Expert Reviews measured a Silentnight Comfort Control double (rated 70W) at 52.5W on its highest setting while warming up, which would be about 11.1p over eight hours at 26.32p/kWh. It also measured a Slumberdown single at 47W on full power while heating up, using 0.02kWh in 30 minutes. Each is one test of one blanket, so treat them as examples, not averages.
“Costs as little as 1p” claims. Argos’s listing for the 70W Slumberdown Warm Hugs says all-night use averages 1p a night. At 26.32p/kWh, 1p is about 0.038kWh, so over eight hours that implies an average draw under 5W, and the listing does not say which setting, room temperature or unit rate it assumes. A one-hour pre-heat on the lowest setting does cost less than 1p on the supplier-advised figures above (about 0.3p for the single and 0.6p for the double), so shorter claims can be reasonable. We have not treated an all-night “1p” as a typical figure.
Other factors. The type of blanket, the room temperature, whether you use a timer or auto shut-off, whether a dual-control blanket is heating both sides and how thick your bedding is can all change run time and use.
Pre-heat the bed or leave the blanket on?
Pre-heating is the cheaper pattern to cost, and it matches fire service guidance to unplug the blanket before you get into bed unless it is designed for all-night use. At 70W, 30 minutes of pre-heating costs about 0.9p.
If your blanket is designed for all-night use, you can estimate a mixed night. Using the supplier-advised Silentnight double figures above, 30 minutes on setting 3 (70W) followed by 7.5 hours on setting 1 (22W):
(0.07kW × 0.5 hours) + (0.022kW × 7.5 hours) = 0.035kWh + 0.165kWh = 0.2kWh → 0.2 × £0.2632 = £0.053 (about 5.3p)
That is an upper estimate, because it assumes setting 1 draws its full 22W the whole time.
For illustration only, over 120 nights (an arbitrary stand-in for a winter, not a typical figure), a 70W blanket used for a 30-minute pre-heat would use 4.2kWh and cost about £1.11. The same blanket at full power for eight hours every night would use 67.2kWh and cost about £17.69. Your own pattern will differ.
Electric blanket vs portable electric heater
| Appliance | Rated power | Per hour | 8 hours |
|---|---|---|---|
| Double underblanket (example) | 70W | 1.8p | 14.7p |
| Heated throw (example) | 150W | 3.9p | 31.6p |
| Portable electric heater (typical maximum) | 2,000W | 52.6p | £4.21 |
Which? says most portable electric heaters have a maximum output of 2kW, so at full power a heater draws roughly 20 to 30 times as much as a 70W to 100W blanket. The comparison is not like for like. A blanket warms you in bed, a heater warms a room, and heaters usually cycle on and off with a thermostat. We cannot say what either would do to your bill, and a blanket does not deal with the cause of a cold or damp home.
How to measure your electric blanket’s real electricity use
For a result based on your own blanket, measure it rather than rely on the label.
- Read the blanket’s instructions. Some manufacturers do not allow adaptors, timers or extension leads, and a plug-in energy meter is an adaptor. If the instructions rule it out, rely on the label figure and the calculator instead.
- If it is allowed, plug a UK Type G plug-in energy meter directly into a dry wall socket and plug the blanket’s mains lead into the meter. Electric blankets draw far less than a typical meter’s rated load, but check the meter’s maximum load anyway.
- Reset the meter and use the blanket as you normally would for several nights.
- Record the total kWh and the number of nights.
- Multiply the kWh by the unit rate on your bill, then divide by the number of nights for an average.
Do not use an extension lead just to reach the meter, and keep leads, controllers and meters dry. A smart plug with energy monitoring can also record kWh (see our UK smart plug comparison → ), but we would not use one to switch a blanket on automatically or remotely unless the manufacturer’s instructions explicitly allow it. For the full method, see how to measure an appliance's electricity use → .
Electric blanket safety checks
Running cost is the smaller question with an electric blanket. UK fire and rescue services, including Manchester, Devon and Somerset and West Yorkshire, give consistent core advice:
- Check the age and the mark. Replace a blanket that is more than 10 years old, buy new rather than second-hand, and look for a UK safety mark such as UKCA or CE.
- Inspect before use, especially after storage. Look for scorch marks, frayed fabric, exposed wires or damaged cords. If in doubt, do not use it.
- Unplug before sleeping unless the blanket has a thermostat control designed for all-night use.
- Lay it flat. Never use it folded, creased or bunched, and store it flat or loosely rolled.
- Keep it dry. Never use a hot water bottle with it, never use a wet or damp blanket, and keep drinks away.
- Follow the instructions on washing, controllers and underblanket or overblanket use. Retailer product information and EDF’s guide also say not to use a blanket for infants, helpless persons or people who are insensitive to heat.
- Check suitability. Fire services advise against use with pressure-relieving devices or with incontinence, and to check with your GP or the device maker before use with a pacemaker or similar medical device. Ask the blanket and mattress manufacturers about adjustable beds and memory foam.
Some fire services also suggest having the blanket checked by a qualified technician every three years. Follow your manufacturer’s instructions, and see Electrical Safety First for UK electrical safety advice.
Ways to avoid unnecessary running
Blankets are usually a small part of a household’s electricity use, so these steps are about avoiding waste, not promising a saving. They may help you identify where your use goes.
- Use the lowest setting that keeps you comfortable, and follow the manufacturer’s advice on turning down once warm.
- Use a timer or auto shut-off if your blanket has one, and switch off and unplug it when you are not using it.
- If you have a dual-control blanket, check whether the instructions allow you to set an unused side to off.
- Measure it once. A real kWh figure is more useful than a label rating.
Use your unit rate, not the standing charge
Your bill has two separate electricity costs:
- Unit rate: the price per kWh of electricity used. This is the figure that changes when you use a blanket.
- Standing charge: a fixed daily charge you normally pay whether or not the blanket is on. For context, Ofgem’s average price-cap standing charge for the same period is 54.83p per day.
For more detail, see electricity unit rate vs standing charge → .
Frequently asked questions
How much electricity does an electric blanket use per hour?
It depends on the rated power. A 40W single blanket uses 0.04kWh per hour and a 70W double uses 0.07kWh, which cost about 1.1p and 1.8p at 26.32p/kWh if they draw their full rated power. A 100W blanket costs about 2.6p per hour. Many blankets draw less once warm, so measure yours for a real figure.How much does it cost to run an electric blanket all night?
At full rated power for eight hours, a 40W blanket costs about 8.4p, a 70W blanket about 14.7p and a 100W blanket about 21.1p at 26.32p/kWh. Using supplier-advised figures for one Silentnight double, eight hours on its lowest setting (22W) would cost about 4.6p. Only leave a blanket on overnight if it has a thermostat control and its instructions say it is designed for all-night use.Is it safe to leave an electric blanket on all night?
Only if the blanket is designed for it. UK fire and rescue services advise unplugging an electric blanket before you get into bed unless it has thermostatic controls designed for safe all-night use. Always follow the manufacturer’s instructions, never use the blanket folded or creased, never use it with a hot water bottle, and replace it once it is more than 10 years old.Is an electric blanket cheaper to run than a heater?
Per hour at full power, usually far cheaper: a 70W blanket costs about 1.8p and a 2kW portable heater about 52.6p at 26.32p/kWh. They do different jobs, though, because a blanket warms you in bed and a heater warms a room. We cannot say what either would do to your own bill, which depends on how long you use them and your tariff.Does a heated throw use more electricity than an underblanket?
Often, but check the label. In the UK listings we checked, underblankets were rated at 40W to 100W and heated throws at 100W, 150W and 300W. At 26.32p/kWh, a 150W throw costs about 3.9p per hour and a 300W throw about 7.9p per hour at full power.Does a lower heat setting use less electricity?
Generally yes. Supplier-advised figures relayed in Argos product Q&A for Silentnight Comfort Control blankets show a double drawing 22W, 44W and 70W on settings 1, 2 and 3, and a single drawing 12W, 25W and 40W. The supplier says its highest-setting figure includes the warm-up stage. Other brands and models differ, so check your manual.Do I include the standing charge when working out an electric blanket's cost?
No. The standing charge is a fixed daily cost you normally pay whether or not the blanket is on. Eight hours at 70W uses 0.56kWh and costs about 14.7p; adding the 54.83p daily standing charge would wrongly give about 70p. See unit rate vs standing charge.How can I measure my electric blanket's real electricity use?
Check the instructions first, because some manufacturers do not allow adaptors, timers or extension leads. If a plug-in energy meter is allowed, plug the meter into the wall socket, plug the blanket into the meter, use the blanket as you normally would and read the kWh after a few nights. Multiply the kWh by your unit rate. Keep the meter and leads dry and never use a damaged blanket.Related guides
- How to measure appliance electricity use →
- Electricity unit rate vs standing charge →
- Ofgem price cap explained →
- How much electricity does a fan use? →
- How much does a dehumidifier cost to run? →
- More appliance running-cost guides →
Sources (checked 11 October 2026): Ofgem: changes to the energy price cap, 1 October to 31 December 2026; Fire and Rescue Service advice from Manchester, Devon and Somerset, West Yorkshire, Essex and Staffordshire (via Lichfield District Council).
This guide is general information, not personalised energy, financial or electrical advice. Rates and product specifications change, so check your own bill and your blanket’s rating label and instructions. This page does not currently contain affiliate links, and we will say so clearly if that changes. See our affiliate disclosure.