Consumer expert Grace Forrell has warned that using a hot water bottle and an electric blanket at the same time is a "massive hazard" and should never be done. She also addressed whether it is cheaper to keep heating on low all day.
Warning on combining heat sources
Ms Forrell, a regular contributor on ITV's This Morning, took to Instagram to explain that some people may consider doubling up in bed with an electric blanket as the weather gets colder. She said people should "under no circumstances" do it.
She also looked at the long-running debate over whether it is cheaper to keep heating on low throughout the day rather than turning it up when you feel cold. Many households believe maintaining a steady temperature is more cost-effective, but Ms Forrell warned that people make "three mistakes" with their heating.
Three common heating mistakes
She explained: "Number one, keeping your heating on low all day rather than turning it on and off. Unless you have a heat pump, it's almost always cheaper to turn it off when you're not in and you don't need it. So, use your timers so you don't forget."
"Number two, cranking your thermostat up to a high temperature thinking it will heat a cold house more quickly. Your house won't get warmer any quicker by doing this, but it will push your heating costs up.
"And number three, using a hot water bottle and an electric blanket at the same time. This is a massive hazard, so don't ever use them together. Pick one or the other."
Energy bills and expert advice
The advice comes as households continue to grapple with soaring energy bills. The UK energy price cap rose by 3.6% (rounded to 4%) on 1 October 2026, pushing the average annual bill for a typical dual-fuel household paying by monthly Direct Debit to £1,723. Prices are further predicted to increase by more than 20% in January.
The Energy Saving Trust argues that keeping the heating on throughout the day is the less efficient choice. It advocates the most straightforward approach: heat your home only when necessary, meaning you pay solely for what you actually use.
It said: "Generally, you should put the heating on when you start to feel cold. This is especially important if anyone in your home is an older person or someone with a medical condition."
On the question of whether it's better to leave the heating on all day, the EST said: "If you have a boiler, then no. Keeping your heating on all the time will use more energy and cost you more money. It's more energy efficient and better for your bills to have your boiler come on when you need it. But if you have a heat pump, then you can save money by leaving the heating on all day."
Checks before winter
Appearing on This Morning this week, Ms Forrell told hosts Cat Deeley and Ben Shephard: "It's really up to you when you choose to turn your heating on. From a safety point of view, you don't really want to be sitting in a room that's colder than 18° during the day.
"And if you're elderly or you have certain medical conditions, you want that to be a few degrees warmer is the minimum as well. But you can pick up decent room thermometers for around £10. You can get them on the high street or online and they can help you track the temperature inside so you know when to switch it on."
She outlined three key things people need to check: check carbon monoxide detectors, test the alarm and see if there's an expiry date; bleed radiators and clean the insides; and service the boiler.
She explained: "Now is a really good time of year to do various checks. One is checking your boiler. Now, gas boilers should be serviced annually. So, if you haven't had yours serviced in a while, now is the time to do it because if you wait until winter and it packs in, you'll probably have to pay quite a high call out fee because demand will be high and you'll be without heating at the coldest time.
"So, getting your boiler checked, it will just ensure everything's working as it should be before you really start putting it through its paces. It costs around £100. Make sure you're using an engineer who's on the gas safe register. And if you rent, your landlord is responsible for the gas safety checks and for maintaining your boiler as well."
