Running cost barely separates these two electric underblankets. Warming the bed for half an hour on full heat costs 1.6p with both sides of the Silentnight Dual Control on and 0.9p with the Carmen Double, at the October 2026 price cap of 26.32p per kWh. Over a 150-night winter of half-hour pre-heats that is £2.37 against £1.38. What you are really choosing between is £20 of price and how much of the bed gets warm: on 8 November 2026 the Silentnight cost £40.00 on its maker's shop and the Carmen £19.99 on its maker's shop.
Neither maker gives you a running cost you can rely on. Carmen's own shop says its blanket costs "just 1p per night to run". Its Amazon listing, and retailers such as Dunelm, say 14p a night. Silentnight's own page publishes no wattage at all, while its Amazon listing claims "from just 1p per hour".
The verdict, 8 November 2026
- An hour on full heat at 26.32p per kWh: Silentnight 3.2p with both sides on (2 × 60W), 1.6p with one side; Carmen 1.8p (70W).
- Heated area: Silentnight 137 × 150cm, about 80% of a standard double; Carmen 120 × 107cm, about half.
- Price on each maker's shop: Silentnight £40.00, Carmen £19.99. Both carry three years of cover, Carmen's only if you register it.
- Buy the Silentnight for a shared bed where one of you runs warmer. Buy the Carmen if you sleep alone, or only want to take the chill off the middle of the bed.
| Silentnight Dual Control, double | Carmen Double Heated Under Blanket (C81193) | |
|---|---|---|
| Power | 2 × 60W (High Street TV listing; Silentnight's own page gives none) | 70W on the title and listings; 60W in the spec table on Carmen's own shop |
| An hour on full heat | 3.2p both sides, 1.6p one side | 1.8p at 70W |
| Half-hour pre-heat, full | 1.6p | 0.9p |
| Heated size | 137 × 150cm | 120 × 107cm |
| Share of a 135 × 190cm double | About 80% | About 50% |
| Controls | Two, one each side, 3 settings each | One, 3 settings |
| Price on the maker's shop | £40.00 | £19.99 |
| Guarantee | 3 years (Silentnight's page) | 1 year, plus 2 more if registered online |
| Running cost the maker states | None on its own page; "from just 1p per hour" on Amazon | "1p per night" on its own shop; "14p per night" on Amazon |
Prices and specs last checked by Look Into on 8 November 2026 · next check 1 January 2027 · how we picked
What an hour, a night and a winter cost
An hour costs watts times hours times the unit rate. For the Silentnight with both controllers on full: 0.12 kW × 26.32p = 3.2p. For the Carmen on full: 0.07 kW × 26.32p = 1.8p. These are ceilings. Both blankets cycle their heat once the bed is warm, and lower settings draw less.
| How you use it | Silentnight, both sides | Carmen |
|---|---|---|
| Half-hour pre-heat, then off | 1.6p a night, £2.37 a winter | 0.9p a night, £1.38 a winter |
| Eight hours on all night | 25.3p a night, £37.90 a winter | 14.7p a night, £22.11 a winter |
Used the way Silentnight's own page advises, which is to switch off before you fall asleep, the difference over a whole winter is under a pound. Only all-night use makes the running cost worth weighing, and even then the Silentnight is heating a much bigger area. Per square metre of heated blanket an hour on full costs about the same on both: 1.5p for the Silentnight and 1.4p for the Carmen.
1p a night, or 14p?
Carmen's own shop, under the C81193 code, says the blanket costs "just 1p per night to run", with an asterisk and no footnote. Its Amazon listing says "just 14p per night". Both cannot describe the same use.
At 70W and 26.32p a unit, 14p buys about 7.6 hours on full, which fits a whole night. 1p buys about 33 minutes, which fits a pre-heat. Each figure could be true for one way of using the blanket. Neither page says which way, or what rate it assumes, so you cannot use either to compare.
The same shop page cannot settle the blanket's power either. Its heading and feature list say "a powerful 70W output". Its specification table says "60W output". At 60W an hour on full would be 1.6p instead of 1.8p. We have used 70W, the figure in the product title.
The listing that disagrees with itself three times
Silentnight's Amazon listing for the double dual control blanket, read on 8 November 2026, says 137 × 150cm in its title but "160 cm x 200 cm" in a bullet point. It says "4 heat settings" where Silentnight's own page says three on each controller. It offers a "3-year manufacturers guarantee" in one bullet and a "Two-year warranty" in its product details. Silentnight's own page settles all three, so we have used its figures.
What Silentnight's own page does not give is a wattage. The 2 × 60W in our sums comes from High Street TV's listing, which pairs it with the double's 137 × 150cm size. If you want the figure from the source, it should be printed on the controller.
How much of the bed gets warm
A standard UK double mattress is 135 × 190cm. The Silentnight's 137 × 150cm covers about 80% of it, leaving the foot end cool. The Carmen's 120 × 107cm covers about half, so on most doubles it warms the middle of the bed and neither person's feet. That is fine for one sleeper, and the reason most of the £20 is worth paying for two.
Which one to buy
Buy the Silentnight Dual Control if you share the bed. Two controllers means each half heats to its own setting, and it covers far more of the mattress. It costs £20 more and a penny or two more a night, which is the whole of the difference.
Buy the Carmen if you sleep alone, or if all you want is a warm patch before you get in. At £19.99 it is half the price, and on a half-hour pre-heat it costs less than a penny a night. Register it online, or you only get one year of guarantee.
How we worked it out
| Item | What we did |
|---|---|
| Electricity rate | 26.32p per kWh, the Ofgem cap for 1 October to 31 December 2026, direct debit, Great Britain average, no VAT on electricity this quarter. |
| Power | Silentnight 2 × 60W from High Street TV's listing, since Silentnight's own page states none. Carmen 70W from its product title, shop heading and Amazon listing; its shop's spec table says 60W. |
| Costs | Rated power for the whole period, the most it could cost. Real use is lower once the thermostat cuts in, and on lower settings. |
| Winter | 150 nights, an assumption, not a measured season. |
| Prices | Each maker's own shop: Silentnight £40.00, Carmen (Swan shop, SKU C81193) £19.99. Amazon had the Silentnight at £39.99, sold by Amazon, and no buy box for the Carmen. |
| Bed size | 135 × 190cm, the standard UK double. |
What this comparison could not check
- We have not used either blanket, and we did not meter them. Every cost is rated power, the ceiling.
- The Silentnight's wattage from Silentnight itself. Its own page gives none.
- Which of Carmen's two wattages, or its two running costs, is current.
- Whether either is designed for all-night use. Silentnight's page advises switching off before sleep; Carmen's markets warmth "all night long".
Today's Amazon prices
These boxes pull Amazon's live price when you load the page, so they can differ from the figures above, which were read on 8 November 2026. Look Into earns a commission if you buy through them; it does not change the verdict.
As an Amazon Associate, Look Into earns from qualifying purchases. Product prices and availability are accurate as of 11 September 2026 7:04 am and are subject to change.
As an Amazon Associate, Look Into earns from qualifying purchases. Product prices and availability are accurate as of 8 November 2026 2:07 pm and are subject to change.
The two blankets
Silentnight Dual Control Electric Blanket, double
At most 3.2p an hour with both sides on full at the October 2026 cap. Two controllers with three settings each, over 137 × 150cm of heated area. Silentnight's own page gives a three-year guarantee.
The catch: Silentnight does not publish its wattage, and its Amazon listing gives two sizes and two guarantee lengths.
Carmen Double Heated Under Blanket (C81193)
At most 1.8p an hour on full at the October 2026 cap, on its 70W rating. Three heat settings, and a controller that detaches so the blanket can go in the wash.
The catch: at 120 × 107cm it warms about half a double, and the third year of guarantee needs online registration.
Look Into earns a commission on qualifying purchases made through the Amazon links above, at no extra cost to you. It never changes the arithmetic.
Common questions
Is the Carmen cheaper to run than the Silentnight Dual Control?
Yes, slightly. On full heat at 26.32p per kWh an hour costs 1.8p for the 70W Carmen and 3.2p for the Silentnight with both 60W sides on. On a half-hour pre-heat the difference over a 150-night winter is under a pound.
Does the Carmen electric blanket cost 1p or 14p a night?
Carmen's own shop says 1p and its Amazon listing says 14p, and neither says how long or at what rate. At 70W and 26.32p per kWh, 1p is about 33 minutes on full and 14p is about 7.6 hours.
What size is the Silentnight Dual Control double electric blanket?
137 × 150cm on Silentnight's own page and in the Amazon title. A bullet on the Amazon listing says 160 × 200cm, which does not match.
Will the Carmen double cover my whole bed?
No. At 120 × 107cm it covers about half of a 135 × 190cm double, so it warms the middle of the bed.
Compare more
- All our running-cost head-to-heads
- Best electric blankets and heated throws UK
- Electric blanket vs heater
- Electric blanket vs hot water bottle
Sources
- Ofgem, changes to the energy price cap between 1 October and 31 December 2026
- Silentnight, Yours & Mine Dual Control Electric Blanket (£40.00, 137 × 150cm, 3 settings each side, 3-year warranty)
- High Street TV, Silentnight Yours & Mine Dual Control (2 × 60W)
- Swan shop, Carmen Double Heated Under Blanket C81193 (£19.99, 70W and 60W, "1p per night")
- Amazon UK listings for the Silentnight Dual Control double (B0777K6KK7) and the Carmen C81193 (B0CHS28R48), read 8 November 2026
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