Electric underblankets: what to know before you buy
The UK's go-to way to warm a cold bed for pennies a night
As an Amazon Associate we earn from qualifying purchases. It costs you nothing extra. We haven't tested this product ourselves; this page pulls together what's publicly known.
With the energy price cap rising again this winter, more UK households are looking for cheap ways to stay warm without turning the heating up. An electric underblanket is one of the simplest options: it sits under your sheet and warms the bed before you get in, so you can turn the thermostat down a notch and still climb into a cosy bed.
This guide explains why electric blankets have become so popular again, who they genuinely suit, and what to check before you buy one — without any invented ratings or made-up specs.
Why everyone's buying it
Interest in electric blankets tends to spike whenever energy bills rise, and this winter is no exception. Ofgem confirmed a 4% increase to the energy price cap for October to December 2026, pushing the typical dual-fuel bill from £1,663 to £1,723 a year. Warming just the bed, rather than a whole room or house, for an hour or so before sleep is a much smaller cost than running central heating for longer. That's reflected in sustained demand on Amazon UK: the Silentnight Comfort Control Electric Blanket (Double) has built up tens of thousands of customer reviews and continues to rank among the top-selling items in Amazon's home category, which suggests it's a product people keep coming back to buy each winter rather than a one-off fad.
- Ofgem confirmed a 4% rise in the energy price cap for 1 October to 31 December 2026, taking the typical dual-fuel bill from £1,663 to £1,723 (source, checked 2026-09-29)
- The Silentnight Comfort Control Electric Blanket (Double) has amassed 36,859 customer reviews at 4.4 out of 5 stars (source, checked 2026-09-29)
- With an overall rating of 4.4 stars, the Silentnight Comfort Control Electric Blanket has over 30,000 five-star ratings and remains in the top three trending items across all of Amazon UK's home range (source, checked 2026-09-29)
- Pre-heating your bed for one hour on a low heat setting costs from as little as 1p (source, checked 2026-09-29)
Good for
- Anyone on a standard or default energy tariff trying to cut heating costs without giving up a warm bed
- People who feel the cold at night but don't want to heat rooms they're not using
- Households with a spare hour before bed to let the blanket pre-heat the mattress
- Anyone whose current heating set-up leaves bedrooms noticeably colder than living areas
Skip it if
- You need something to stay warm all night rather than just at bedtime — most underblankets are designed to pre-heat, not run continuously while you sleep, and manufacturer guidance usually advises against sleeping with them switched on
- You share a bed with someone who prefers a different temperature, since a single underblanket without dual controls will heat the whole bed evenly
- You have a health condition, mobility issue, or are pregnant — check manufacturer guidance and, if in doubt, ask a GP or pharmacist before using any electric heating product in bed
- You're not able to check on the blanket's condition regularly, as any electric blanket needs periodic inspection for wear, especially after several winters of use
Check before you buy
- Bed size — underblankets are sold by size (single, double, king etc.) and need to match your mattress
- Single or dual control — some blankets let two people on a double or king bed set their own side's temperature; others only have one control for the whole blanket
- Number of heat settings and whether there's a timer or auto-shut-off, so you don't have to remember to switch it off
- Whether it's machine washable, since bedding needs washing regularly and not all electric blankets are
- Current price and any seller information on Amazon, as prices and stock can change
- How the blanket fastens to the mattress — elastic corner straps are common but check they'll suit the depth of your mattress
Alternatives worth a look
Sits on top of you on the sofa rather than under a fitted sheet, useful for evenings in the living room rather than warming the bed itself
See options on AmazonA low-tech, no-electricity option for warming a small area of the bed or for cuddling while reading, with no wiring to check over time
See options on AmazonReusable, cordless warmth you heat in the microwave — handy for a quick warm-up spot in bed without leaving anything plugged in overnight
See options on AmazonAdds warmth passively with no running cost at all, and pairs well with an underblanket if you want extra insulation without turning the heat up
See options on AmazonKeeps you warm in bed all night long, which an electric underblanket typically isn't designed to do once you're asleep
See options on AmazonQuestions
Most manufacturers advise pre-heating the bed before you get in and then switching the blanket off, rather than leaving it running while you sleep. Always follow the specific guidance that comes with the blanket you buy.
It can, if you use it to justify turning your room heating down rather than running both. The exact saving depends on your energy tariff, how long you run the blanket, and what heating habit it replaces, so it's worth comparing against your own bills rather than relying on a general figure.
Some are machine washable and some aren't — this varies by product, so check the specific care instructions before you buy rather than assuming.
If you share a double or king bed and want different temperatures on each side, look for a blanket with dual (his-and-hers) controls. If one person sleeps alone or you're both happy with the same setting, a single control is simpler and usually cheaper.