Electric blanket versus hot water bottle - which is the cheapest to use?

These alternatives to central heating can save you a considerable sum of money, but which is the cheapest of the two?

Electric blanket versus hot water bottle spliced image
(Image credit: Future)

Staying warm at home while keeping energy bills down will be a challenge for millions of households this winter. With many families still worried about how much their energy bills will cost (opens in new tab) and choosing to keep the heating off as much as possible, it’s no wonder that we're looking for cheap ways to keep warm (opens in new tab) and have seen demand for both electric blankets and hot water bottles reportedly rise in recent months. But which is cheapest to use - a hot water bottle or an electric blanket?

Founder of HUGO Energy App, Ben Dhesi (opens in new tab), told us: “Electric blankets and hot water bottles are two of Britain's favourite ways of staying cosy and warm, but it's important to know which one is cheapest to use so we can use energy responsibly this winter. With the rising cost of energy, it's important to find ways to keep warm this winter without breaking the bank.”

Thanks to the introduction of the Energy Price Guarantee (opens in new tab), energy bills won’t rise as much as originally feared this winter. All households who pay for their energy will also receive a £400 energy rebate (opens in new tab) between October 2022 and March 2023. But despite this financial support, energy bills are still far higher than they were a year ago and many families will struggle to make ends meet.

Electric blanket versus hot water bottle - which is cheaper to use? 

A hot water bottle is cheaper to use than an electric blanket, according to our calculations. 

A typical 150W electric blanket costs about 5.1p an hour to run, based on the Energy Price Guarantee’s electricity unit price of 34p per kWh. If you were to use it for eight hours a day, this would cost you 40.8p. (You can see a full breakdown of how much it costs to run an electric blanket (opens in new tab) in our handy guide).

In comparison, to fill an average hot water bottle of two litres, you’ll need to boil a full kettle of water. When it comes to how much it costs to boil a kettle (opens in new tab), you can expect to pay around 6.8p a time.

A hot water bottle should stay warm for around three hours, especially if it has a cover. If you were to fill your hot water bottle three times a day, that would cost you 20.4p a day, half of what it would cost you to run an electric blanket. 

The table below shows the costs per day, month and year:

Swipe to scroll horizontally
Header Cell - Column 0 Cost per dayCost per monthCost per year (if used between October and March)
Electric blanket40.8p£12.40£74.40
Hot water bottle20.4p£6.20£37.20

graphic showing electric blanket versus hot water bottle

(Image credit: Future)

But which is more effective at keeping you warm - an electric blanket or hot water bottle?  

Overall, electric blankets are likely to be more effective at keeping you warm as they can heat up a whole bed or cover your entire body and won’t cool down like a hot water bottle will. 

Founder and CEO of Eco Energy Geek, Adam Smith (opens in new tab), says: “Electric blankets are very convenient and easy to use. They can be used to preheat a bed before getting in or to keep a person warm while sleeping or working. They can also be used to provide extra warmth for people who are cold-sensitive or have circulation problems.”

However, some people find hot water bottles more comforting and they have the advantage of being cheaper to buy. You can pick up a hot water bottle for as little as £6, compared to around £30-£70 for an electric blanket. 

Can you use a hot water bottle with an electric blanket?

No, using a hot water bottle with an electric blanket is not recommended as you are at risk of being electrocuted if the bottle leaks.

It’s also important to take care if you are using these heat sources for children. Electric blankets should not be used for children under five, and if you are using them at night, your child must be fully toilet trained. As standard, most electric blankets now have built-in safety features to stop them from overheating, but check that it has the UK safety standard mark (the kite mark) before purchasing or using. 

Hayley Thistleton (opens in new tab) from bedding manufacturers Sleepseeker (opens in new tab), says: “It is much safer to use layers of clothing and blankets to keep your child safely warm. However, if you must use an electric blanket to warm your child’s bed, ensure you’re only doing so to warm the bed before your child sleeps in the bed.”

Hot water bottles should not be given to children younger than four, and it is safest not to let young children have them in bed. Regularly check the hot water bottle for wear and tear and replace it every one to two years. The hot water bottle should always have a cover and the stopper should be secured tightly.

Note that you should only ever fill your hot water bottle to a maximum of two-thirds capacity and it’s best not to use boiling water as this can cause the rubber to corrode, leading to leaks. Instead, once the kettle has boiled, leave it to cool for around five minutes before filling your hot water bottle. 

  • Never use a hot water bottle with an electric blanket
  • Electric blankets are only suitable for children aged 5 and up
  • Hot water bottles are only suitable for children aged 4 and up
  • Hot water bottles should only be filled two-thirds full
  • Only use hot, rather than boiling, water in a hot water bottle.

Is it cheaper to turn up the heating or use an electric blanket? 

It’s generally much cheaper to use an electric blanket than turn up the heating in your home. 

Forbes Advisor’s Kevin Pratt (opens in new tab) told us: “Gas central heating can be a costly way to heat a whole house when you are only occupying one room, on average heating a house is currently £23.10 a week. Instead of heating the whole home, electric blankets can be used to heat one specific spot such as the sofa you're sitting on in the evening, the bed you're about to sleep in or your work-from-home station. Electric blankets are also great if you are in a single person occupancy and multiple rooms aren’t being used at once.” 

How can you make a hot water bottle more effective? 

There are a number of ways you can make your hot water bottle more effective. Ben Dhesi, founder of HUGO Energy App (opens in new tab) explains: “Wrap the bottle in a towel or blanket. This will help to keep the heat in for longer, and ensure it's not too hot to touch.” 

If using it at night, place the bottle near your feet or stomach. “This will help to heat up your body core and keep you warm all night long,” Ben adds. 

Sleeping (or sitting) in a sleeping bag with a hot water bottle will also help your hot water bottle to stay warm for longer.

Rachel is a freelance personal finance journalist who has been writing about everything from mortgages to car insurance for over a decade. Having previously worked at Shares Magazine, where she specialised in small-cap stocks, Rachel developed a passion for consumer finance and saving money when she moved to lovemoney.com (opens in new tab). She later spent more than 8 years as an editor at price comparison site MoneySuperMarket where she helped support the CRM programme, as well as the SEO and PR teams, often acting as spokesperson. Rachel went freelance in 2020, just as the pandemic hit, and has since written for numerous websites and national newspapers, including The Mail on Sunday, The Observer, The Sun and Forbes. She is passionate about helping consumers become more confident with their finances, giving them the tools they need to take control of their money and make savings. In her spare time, Rachel is a keen traveller and baker.