How much does a heated blanket, 12 V cost to run?

About 0.59p an hour in the UK and 0.41¢ an hour in the US. A heated blanket, 12 V draws about 45 W for roughly 50% of the time it is switched on, so it averages 23 W. Runs off the car socket and avoids the inverter entirely — the efficient way to stay warm in a van.

What it costs, by how long it runs

Average draw at Ofgem price cap, Oct to Dec 2026 and EIA US residential average, June 2026
Running for	kWh	UK	US
10 minutes	0.004	0.1p	0.07¢
An hour	0.023	0.59p	0.41¢
An 8-hour night	0.18	4.7p	3.3¢
A full day (24 hours)	0.54	14p	9.9¢
A month at 8 hours a day	5.4	£1.42	99¢

UK prices use the Ofgem price cap for 1 October to 31 December 2026 (direct debit, average across England, Scotland and Wales, with no VAT on electricity this winter): 26.32p per kWh (Ofgem). The standing charge of 54.83p a day is paid whatever you run, so it is left out. US prices use the US average residential price for June 2026 from the Energy Information Administration: 18.34¢ per kWh (EIA). Your own tariff is on your bill; scale the figures by it.

Measure your own

These are typical figures for a typical unit. A plug-in energy monitor between the socket and the appliance shows the real watts and adds up the kWh, so after a day or a week you know exactly what it costs on your tariff.

Plug-in energy monitors

Amazon UK Amazon US

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Compared with similar appliances

Appliance	Average W	UK per hour	US per hour
LED camping lights	10	0.26p	0.18¢
Festoon / string lights	15	0.39p	0.28¢
12 V compressor cool box (Dometic CFX5, Alpicool)	18	0.47p	0.33¢
Car fridge (12 V, 40 L)	18	0.47p	0.33¢
Heated jacket battery	20	0.53p	0.37¢
Heated blanket, 12 V	23	0.59p	0.41¢
Thermoelectric cool box	48	1.3p	0.88¢
E-bike charger	150	3.9p	2.8¢

Running it in a power cut

See which power station will run a heated blanket, 12 V, and for how long.

Appliance draw modelled on web.archive.org. The US Department of Energy retired this page in 2025; the link is the Internet Archive's June 2024 capture. The figures remain typical ranges for a typical unit, not a specification.

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