Quick answer

The blanket off your spare bed is the wrong one: domestic mains blankets are marked for indoor, dry use only and must not go on an inflatable bed, and a tent is none of those things. The closest mains option is a low-wattage blanket sold for caravan and campervan hook-up, on a hook-up pitch, through a proper tent mains unit with an RCD, once the nights are colder than your sleeping bag handles. Without hook-up, look at a 12V camping blanket instead. Treat it as a bed warmer, not a heater. No leaflet? Look up the manual for your model. If you cannot establish what it permits, the answer is no.

Table of contents

Four checks that take about ninety seconds

The calendar is the weakest input here. Four things settle it, and you can run all four while the kettle is on.

One: the pitch, the bollard and what else is drawing off it

UK hook-up pitches are generally rated at 6A, 10A or 16A. The Camping and Caravanning Club says most of its own sites supply 16A but some are limited to 10A, and it warns Certificated Sites can go as low as 5A. It puts the arithmetic on the page: 230V at 10A gives 2,300W, rising to 3.68kW at a 16A site.

The blanket is not what eats that. A Dreamland Intelliheat heated underblanket is rated 150W, and a purpose-made low-wattage camping blanket such as the Kingavon is sold at 35W for caravan and campervan hook-up. The Club's own appliance table puts a domestic kettle at 2,000W and 8.7A, and a high-speed kettle at 3,000W and 13A. It is not the blanket that trips a bollard. It is a high-wattage kettle.

Check the bollard for protection too. Club bollards are individually protected by a miniature circuit breaker and an RCD, and BS 7671 requires that of every UK pitch socket-outlet, but the regulations are not retrospective and an RCD you have not tested is not protection, which is why your own socket unit has to carry one regardless. Sites can also cap what you run: Tyn-Y-Mur in Gwynedd states its hook-up is a 10 amp supply intended for camping-type appliances and should not be overloaded with high-powered electric heaters.

No hook-up? A battery does not change what a mains blanket's instructions say, and the routes that are left are in the next two checks. Our review of the GRECELL T-500 portable power station has the numbers.

Two: what your own leaflet permits

This is the check almost nobody runs, and it decides it for most readers. The Silentnight electric blanket booklet says to ensure the product is only used indoors and in the way it is intended, to only use when dry, and that it must not be used on a sofa bed or inflatable air bed. A separate manual for the same range repeats it: for indoor use only, and do not use with sofa beds or inflatable beds.

Read that against a UK tent pitch. You are outdoors, the air is damp by morning, and a lot of campers sleep on an air bed. If your blanket came off a bed at home, check two is where it stops.

That leaves one class of mains blanket that is at least sold for hook-up use: the low-wattage ones aimed at caravans and campervans, like the 35W Kingavon above. Its listing says home, caravan or campervan and never says tent, and we could not find a published leaflet for it, so the gate above still applies: get the instructions in the box, and if they say indoor and dry use only, the answer is no. If they clear it, use it only on a hook-up pitch through a proper tent mains unit. With no hook-up, read the next check. The air bed is a separate problem and the fix goes under the bed rather than on top: our guide on how to stop an air bed going cold at night covers the layer that works there.

Three: underblanket, overblanket, heated throw or 12V

The type changes the answer, so establish which one is in the boot. A mains underblanket goes on top of the mattress, under the occupant, secured flat with its ties. The manuals are blunt that the two are not interchangeable: Silentnight's underblanket booklet says it must only be used as an underblanket, Dreamland says to place it on top of the mattress and not use it as an overblanket, and Silentnight's throw says to use it as an over blanket only.

A heated throw is a different appliance again. The Silentnight throw booklet says to use it as an over blanket only, that it is intended for household, indoor and dry use only, and, in as many words, do not fall asleep with this device on. That model shuts off after two hours. It is a sofa product, not something to sleep under.

The 12V type is a different proposition. It runs at extra low voltage off a leisure battery or a power station, so there is no mains in the tent and no hook-up to find, and UK sellers do list them for tent camping: BougeRV's UK store names camping in a tent as the first use case, and rates that blanket at 0 to 48W. Treat 12V as the route worth investigating if you have no hook-up, and size your battery against the blanket's published wattage before you buy.

Four: is everything dry, right now

Water is the whole risk, and the Club is direct: tents, and particularly the floors of tents, can be damp, and moisture and electricity do not mix. It tells you not to use electrical equipment on the tent floor, and to be prepared to stop using electricity altogether when conditions in the tent are damp.

That is why the RCD matters more than the amperage. The Club describes it as cutting the supply immediately if current leaks to earth, which can happen when someone touches a damp appliance while standing on damp ground. Every manual says the same thing: only use it when dry, and do not use it if it is wet. Add one rule of our own on top: a blanket that gets wet goes home unused, because switching it on is not a way to dry it.

September to January, month by month

These are Met Office 1991 to 2020 climate district averages for mean overnight minimum temperature, southern lowland England against eastern Scotland. They are averages, so a good number of nights in each month run colder. Use them to know which month you are in; the call column assumes you have already passed the four checks.

MonthEngland SE and central S (C)Scotland E (C)The call
September10.27.6Leave it at home. If you are cold, it is the ground and the bag, not the air.
October7.64.7Pack it only if your blanket passed checks two and three. Mains needs hook-up, 12V does not.
November4.51.9The month it earns its space, if your blanket passed checks two and three. Preheat the bed, then switch off.
December2.3-0.3Same call, plus a mat that can take a frozen pitch. If the tent is damp in the morning, that morning is a no.
January1.9-0.3Same again, and the damp rule bites most this month. Stop and ask whether the bag is the real problem.

Adjust for where you actually are rather than hunting a national date. Eastern Scotland in October averages 4.7C, close to what southern lowland England averages in November. Inland and upland pitches run colder than any district average, so check the forecast for your own pitch rather than the region. Altitude costs roughly half a degree per 100 metres by the Met Office's reckoning, though that figure is quoted for mean annual temperature rather than for nights. Valley floors are colder again because cold air drains into them, and coastal pitches run mildest because the sea holds the frost season off.

September and October: run the checks, not the calendar

Reaching for a mains appliance is the wrong first move in September. Ground insulation and a bag that matches the night do more, for less risk: start with our six steps for staying warm in a tent. October is where the decision becomes real, and the trigger is not a temperature but your own bag's comfort rating against the forecast low for your pitch.

November to January: the season this page is for

By November a southern pitch averages 4.5C overnight and an eastern Scottish one is close to freezing. If your bag's comfort rating sits above the forecast, something has to change, and a blanket is one answer rather than the obvious one. Often the fault is the bag: our review of the SWTMERRY 3-4 season bag is a leave-it verdict on a broken-zip rate we could not get past, and on a spec sheet where the label says winter while the small print gives a comfort range of 10 to 20C. Through December and January, add a mat that copes with frozen ground before you add electricity, which our guide to choosing a sleeping pad for winter camping covers. If your bag does not publish a comfort rating, assume it is a summer bag: the SWTMERRY above is sold as 3-4 season and its own small print puts the comfort range at 10 to 20C and only the survival end at 5C.

Setting one up on the pitch, in order

Steps 2 to 4 are the mains route, on a hook-up pitch. If you are running a 12V blanket there is no mains lead and no socket unit, so skip them and follow that blanket's own instructions, but steps 1, 5 and 6 still apply.

1. Inspect the blanket before it leaves the house. Hold it up to the light and check no wire is visible through the surface and none has looped or twisted back, which is the inspection Silentnight and Dreamland both print in their booklets. Check the flex, plug and connector for cuts, scorch marks or discolouration. If it is over ten years old, Electrical Safety First and the London Fire Brigade both say to replace it.

2. Connect through a tent mains unit, not an extension lead. The Club says it is essential to use a proprietary electric hook-up device made specifically for tent hook-ups, with a control box carrying MCBs and an RCD, and never to substitute a household extension cable. Look for IP44 or better, and press the RCD's test button before you plug anything into it: the switch should drop out. Reset it and you are good.

3. Run the lead, fully uncoiled. The Club recommends a 25m cable so it reaches the bollard at most UK sites, and specifies three-core PVC/PVC at 2.5mm² per core for a caravan's 16A demand. For tents it says something different and more useful: the lead on a proprietary tent unit will likely be the lighter 1.5mm² grade and only 15m long, so pitch within reach of the bollard and keep your total load modest. That lighter grade is what our review of a 25m caravan mains hook-up cable is about: a lead sold as heavy duty on 1.5mm² conductors, fine for a blanket, lights and a fridge, not for sitting near the full 16A. At a blanket's load that is not a problem, and 25m buys the reach a 15m tent lead does not: the 25m hook-up lead we reviewed. Plug into your unit first and the bollard second so you never carry a live lead across the grass, and lay the run along the edge of the pitch, clear of the walking line and of where you are driving pegs.

4. Hang the socket unit up. Off the ground, clipped or hooked to the tent frame, away from fabric where condensation collects.

5. Lay the blanket flat on a proper mattress its straps can grip. Not an air bed and not an inflatable sleeping mat: the leaflets bar inflatable beds as a class, and the Club says not to put electrical equipment on the tent floor at all. A camp bed with a solid mattress is the surface this works on. If your sleeping surface is anything else, a mains blanket stops here. Open it out fully, smooth every packing fold, secure it with its ties so it cannot ruck, and put the controller on top of the bedding rather than under a pillow. Cover the blanket with your sheet and bag, because an underblanket needs covering to work, but keep the mains lead itself at the pillow end and uncovered, which both Silentnight manuals instruct and one of them prints in capitals.

6. Preheat while you are still up, then switch off. A few minutes if the blanket has a preheat setting, longer if the night is cold or your bedding is thin, then get into a warm bed and switch it off and unplug it before you sleep. Leave it on overnight only if that blanket's own leaflet states all-night use, and then only at the setting the leaflet names for it: both Silentnight manuals say low heat setting 1, and Dreamland's all-night setting is 3 of 6.

Where this goes wrong

The controller ends up in the wet. Condensation runs down the inner wall and pools on the groundsheet overnight, and a controller left on the floor is in the one place the Club tells you not to put electrical kit. Keep it on the bedding. If you wake to a damp blanket, unplug and leave it off.

It goes on a child's bed. Silentnight and Dreamland both bar under-threes outright, and Silentnight requires supervision plus the lowest setting from three to eight. Electrical Safety First says the same about infants and anyone whose condition makes them insensitive to heat, and Dreamland tells pacemaker users not to run one all night. In a family tent this is the rule most likely to get broken.

Creases are what the manuals actually warn about. A bed at home holds an underblanket flat with mattress straps. A camp bed gives it much less to grip, so it creases, and every manual on the subject says the same thing: do not use it folded or creased. Silentnight notes that using one folded trips the overheat sensor in the controller, which is the good outcome.

Somebody boils a kettle. The blanket is not the load that decides this: 150W is under an amp, and a domestic kettle at 8.7A plus the blanket still fits inside a 10A pitch. A 3,000W high-speed kettle is 13A, which is over a 10A pitch on its own, blanket or no blanket. Take a camping kettle at 750W, or boil on gas.

The lead stays on its drum. The Club is explicit that you uncoil the supply cable fully to avoid it overheating on a cable reel. A tidy half-wound drum by the bollard is the classic version of this.

Age is the fault you cannot see. When East Sussex Fire and Rescue Service ran a public testing campaign, 200 of 558 blankets failed and were taken out of use. Damage is often not visible from the outside.

A hot water bottle joins in. The London Fire Brigade says never to use a hot water bottle at the same time as an electric blanket. That matters here because a hot water bottle is standard cold-weather camping kit and the two get packed together. If you are choosing between them, our guide on when to start using a hot water bottle camping makes the case for the bottle. Pick one, not both.

It goes home damp. Let it cool and dry fully, then roll it or fold it loosely with no sharp creases.

Frequently asked questions

Can you leave an electric blanket on all night in a tent?

Leave it on overnight only if that blanket's own leaflet states all-night use, and then only at the setting the leaflet names for it: both Silentnight manuals say low heat setting 1, and Dreamland's all-night setting is 3 of 6. Electrical Safety First says to unplug the blanket when you get into bed, and that anything left on overnight needs adjustable temperature control plus automatic shut-off and overheat protection. The London Fire Brigade says to unplug before you get in unless it has a thermostat control for safe all-night use. For tents the Club adds a rule of its own: switch off and unplug whenever nobody is in the tent. Treat it as a bed warmer, not a heater.

Can you put an electric blanket on an air bed?

No, not a mains underblanket. The Silentnight booklet says the blanket must not be used on a sofa bed or inflatable air bed, and a second manual for the same range repeats it. Insulate under the bed instead.

Can you run one off a portable power station instead of hook-up?

A power station supplies the watts but does not change what a mains blanket's own instructions say. The GRECELL T-500 we cover has a 500W ceiling, comfortably above a 150W underblanket, but only 519Wh of capacity, which is about three and a half hours at that draw and not a night. Off hook-up, look at the 12V route in check three instead.

Is the electric blanket off the spare bed safe to take camping?

No. Domestic mains blankets are marked for indoor, dry use only and must not go on an inflatable bed, and a tent is none of those things. Two other routes are open: a low-wattage mains blanket sold for caravan and campervan hook-up, used only on a hook-up pitch through a proper tent mains unit, or a 12V camping blanket off a leisure battery when there is no hook-up.