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29 Dec 2021

Dogs, electric heaters and hot water bottles u2014 which will keep you the warmest this winter?

We look at three ways to keep the cold at bay without whacking up the central heating.
Person embracing a dog

If you just need a temporary heating top up, there are various ways to warm up without necessarily cranking up your central heating. Some of them are typical and some are a little novel.

Which? experts share their insights into three heating quick-fixes, from portable heaters to other living beings. Read on for their verdicts, as well as some key insights from our test lab.

Worried about meeting the costs of heating payments this winter? Head to our guide on getting help if you're struggling to pay your energy bills.

Three ways to keep cosy on cold days

Buy an electric heater

Person using an electric heater

We like: thermostatic control lets you pick a temperature and maintain it, heats a whole room, adjustable heat outputs.

We don't like: electricity costs can sky-rocket, quality varies depending what heater you buy.

Which? expert says: the best thing about portable electric heaters is that they're fitted with thermostats. You can raise the temperature of a medium-sized room by 10°C in around half an hour and then the heater can adjust its output down to maintain the same ambient temperature.

You can also set a timer and toggle the energy output to a lower setting yourself. Not all heaters offer a lot of control, but almost all of them have a lower-energy setting for gentler warming.

We've seen how capable the good ones are in our test lab where we stress-test heaters in difficult climatic environments, and, in terms of speed, coverage and control, they're an unbeatable quick-fix for a cold room.

Their Achilles' Hell is their energy costs. Now more than ever, they drain your money quickly. Unless you only need to heat one zone, a central heating system is superior.

Find the best electric heater for you by reading our electric heater reviews.

Electric heater in a home

Electric heaters are notoriously electricity-guzzling. However, minimum energy efficiency requirements are now imposed on manufacturers.

These requirements are a big help, but we still find that a lot of variance between bad heaters and good ones.

  • An electric heater, on average, will run at 2kW or 3kW outputs.
  • A good fan heater usually needs around 15-20 minutes to heat a medium-sized room sufficiently, but they tend to use more electricity at max settings.
  • Convector and radiator heaters take longer, usually around half an hour using 2kW outputs. In real terms, this means you're using 1kW to go from cold to comfortable.
  • After your room is warmed up, you need to task your heater with maintaining a stable temperature. We've found that only the best can do this. Bad heaters will misjudge the ambient temperature and spew out too much heat, or even under-supply heat to leave you cold again,

One of the pros of an electric heater is that, once it's done the work of heating up your room, it can use much less electricity to maintain the temperature. This makes an electric heater well-suited for longer running periods.

But don't let the costs run away from you. If you use a 2kW heater for an hour every morning and you pay 21p per kWh, then you'll be spending £2.94 a week on it.

We've rounded up 10 ways to save on energy bills to help you keep costs in check this winter.

Snuggle up to a dog or cat

Dog on a sofa

We like: Very snuggly

We don't like: Can be malodorous, you probably won't be able to get up again when you need to.

Which? expert says: My dog is small and fits perfectly on my lap, whether I'm sitting at my home desk or in front of the TV. He keeps me toasty warm and makes me feel loved (something no hot water bottle I've ever owned has managed to do).

He's also a complete love sponge so demands lots of strokes and fuss. This is sweet, but distracting when I'm trying to concentrate - particularly if he wants to lay in my arms like a baby when I'm trying to type.

Also, I can't choose when I get to be cosy. If I get up, he gets affronted and slinks off to his own warm bed. Any hint of a postal visit, a squirrel out the back or a car pulling up, and he's off'.

So does a four-legged friend make a good substitute for a hot water bottle? Only if you agree to its terms.

Cats and dogs are astonishingly good thermal sources: they're warm-blooded mammals that emanate body heat and they're coated in fur that keeps them warm even in bitterly cold conditions.

Of course, pets aren't remotely cheap. Between food, accomodations, vet bills, time, energy, repairs and toys, you will be out of pocket. But the benefits of mutual warmth do come free.

So whether your pet pooch or cuddly cat comes with large overheads, or if it's a perfectly reciprocal relationship, is a matter of perspective.

Remember to keep your pet warm in turn.

The Dogs Trust advice for looking after a dog in cold weather includes:

  • letting your dog's winter coat grow when the weather gets colder
  • getting a winter dog coat for your dog if it's a short-haired breed, puppy or older dog. The Dogs Trust has advice on coaxing a wary dog into wearing a coat
  • keeping your dog on a lead if it's snowing, in case the snow is covering anything unsafe
  • wiping your dog's legs, feet and stomach after a walk, so that grit and damp doesn't irritate their skin
  • never leaving your dog in a car (this applies to hot weather too)
  • keeping your dog active.

Similarly, according to Battersea Dogs and Cats Home, if you're a cat owner, you'll need to:

  • keep your cat warm and dry - particularly older cats or cats with reduced muscle weight
  • check your cats' paws for grit or signs of frostbite. Especially important for longhaired cats who are more vulnerable to snow compacting and forming ice balls between their toes
  • provide an outdoor place to shelter, if your cat wants to come and go
  • provide an indoor litter tray, so there's no obligation to go outside
  • provide lots of toys and stimulation indoors.

In both cases, you should make sure that your dog or cat's microchip is up to date, so that it can be located more easily if it wanders off.

Discover the best and the worst pet insurance.

Get a hot water bottle

Hot water bottle

We like: cheap to buy, highly flexible because you can carry it wherever

We don't like: Only heats up one person, lasts around three hours before it needs reheating

Which? expert says:You can take a hot water bottle anywhere and hold it to any part of your body, whether you're sitting at the desk, lying in bed or out on a walk in the crisp chill.

The problem with this low-tech solution is that hot water bottles have diminishing returns. Hot water bottles don't generate heat like heaters, dogs and other generative sources.

Our tests also showed that you can get about three hours of heat from your hot water bottle before it drops to your body temperature.

Steaming kettle

Remember not to put boiling water into a hot water bottle. Get the water piping hot, but leave it to cool for a short while so it doesn't damage the bottle.

The only energy cost of preparing a hot water bottle is the cost of boiling water. Kettles have wattages comparable to portable heaters (usually around 2kW) but you'll be boiling your kettle for a fraction of the time, so they work out much cheaper.

Our recent tests of hot water bottles bear good news: you don't need to spend more to get a better product.

Our expert who tested them said 'As we recorded the temperature drops over several hours, we found that all of the hot water bottles were within 2°C of each other on average when we ran our tests with the covers off.'

This makes the 'running costs' of a hot water bottle about equivalent to boiling a cup of tea every three hours.

Find out which hot water bottle we tested keeps you toasty the longest.

If fan heaters, fluffy water bottles or Fido aren't enough to keep you warm this winter, take a look at our heating and air treatment guides to find more serious advice on other solutions including boilers, smart thermostats, and home heating systems.