If, with the sudden arrival of damp and colder weather you've seen claims 'this is the date you need to turn your heating on', the rising cost of energy bills means you could be hoping this date is still far in the future.
The truth is, saying there's a set date is actually a myth. Dates aren't that important. When it comes to when to turn your heating on, other factors are more influential, and we're here to explain what these are.
After all, getting it right isn't just for our own benefit – even though it's easy to think it is. The stark truth is that turning your heating on too late isn't just risky for your own well-being, but also the health of your home. So, when should you turn your heating on?
Why isn't there any truth in claims there's a specific date to turn the heating on?
It's unfortunately a case of don't believe everything you read when it comes to dates for switching your heating off and on. In the same way we look at when to turn off your heating in spring, there is one main factor determining when you should turn your heating on in the autumn – and it's not date related.
It's simply the temperature both inside and outside your home that tells you when it's time to turn up the dial – not the calendar.
Yes, you could argue that the first time the temperature hits the recommended number, is the date, but there's a second factor involved, and that's consistency.
One-off drops in temperature can normally be dealt with by adding a few layers of clothing, or adding a burst of heat by firing up your fireplace for the night, but when the temperature falls for a longer period of time, that's when you know you can no longer avoid the inevitable.
What temperature tells me I need to turn my heating on?
When we asked the experts what temperature it needs to be in order to turn on the heating, they all conclusively agreed the golden number is when the temp falls to 18°C or below, inside your home.
“We usually advise that once the temperature inside your home consistently drops below 18°C, it’s a good sign it’s time to think about turning the heating back on," confirms Ryan Willdig, sales director at Heatforce.
"That’s the level recommended by health experts for maintaining a safe and comfortable living environment, particularly for children, older people, and anyone with existing health conditions," he explains. It can also be referred to as the ambient temperature.
“It can vary for individuals, rooms and home set up," adds Adam Knight, Lead Engineer at BOXT, "however generally, when the inside temperature of your home reaches around 18 – 19°C or lower for most of the day, people start to feel the cold and turn their heating on. Vulnerable people may feel the cold sooner."
But what about the temperature outside?
"Outdoors, you’ll often notice that when the daytime temperature dips below 15°C, it becomes harder to keep that cosy feel without a little help from your heating," says Nick Duggan director at The Radiator Centre. So, if the weather forecast is predicting a longer cold spell, it's probably time to think about turning your heating on.
That said, there are also other signs you can take into account too.
"Another sign is if you’re seeing persistent condensation on windows in the morning. Use your home's response to temperature and a smart thermostat as your triggers, rather than a weather app,” suggests Adam Knight.
It's important to remember personal preference will play a part too, adds Nick Duggan. "The big indicator is comfort, if your home starts to feel chilly, that’s usually your cue," he advises." Other tell-tale signs are that you’re reaching for an extra jumper in the evening, or your hands feel cold when you wake up."
Ryan is the Sales Director and a heating and plumbing expert at Heatforce, one of the UK’s leading home energy installers, based in Cardiff and servicing the West Midlands, South-West and South-East of England. Specialising in heat pumps, solar PV, and hybrid systems, the company has supported thousands of homeowners in making the switch to low-carbon heating, saving customers hundreds of pounds and contributing towards a better planet.
Adam Knight is a Lead Engineer at heating and cooling experts, BOXT. Adam brings over 17 years of industry experience, including 14 years at British Gas specialising in auditing, gas qualifications, and incident investigations, and now leads BOXT’s Tech Survey Team with specialist training in air conditioning and heat pump systems.
Nick has over 20 years of experience in central heating, leading the team at one of the UK's largest independent suppliers of radiators.
What are the risks of not turning my heating on when the temperature falls?
Still determined to see it out for a few degrees more? It may not always be the best idea warn our experts, providing a host of reasons why it's not good for you, or your home.
“We wouldn’t recommend letting your home fall below 16°C, even if you’re trying to hold off turning the heating back on for as long as possible. Below this point, your living environment can quickly become uncomfortable," says Ryan Willdig.
"While it can be tempting to wait, running your heating at low, controlled levels to keep your home at or above this baseline will protect both your wellbeing and the condition of your property," he explains.
“Going below 18°C means you risk cold, damp and condensation," adds Adam Knight. "That’s not just uncomfortable – it can also encourage mould. Keeping a steady baseline helps maintain the building fabric and lets your system run efficiently.
"It’s also important during a cold snap to ensure your heating is on periodically, otherwise water pipes can freeze and burst," he adds. "This is most important for boilers located in outbuildings, lofts or garages.”
And, while you may feel like you're saving money by not turning the heating on, it's not usually the case, adds Nick Duggan. "You risk higher heating bills later because radiators need to work harder to bring the temperature back up. Maintaining a steady background warmth is far more efficient than letting your home get very cold and then trying to heat it quickly," he says.
Plus, there are key benefits to not leaving your system idle for too long. "If temperatures drop too low, your boiler and pipework have to work much harder when you finally switch the heating back on, this can put unnecessary strain on the system and lead to breakdowns at the worst possible time," says Ryan.
As well as your boiler and pipework, the emitters inside your home can also benefit from more regular use, adds Nick.
"Inactivity can cause pumps and valves to seize up and allow sludge to settle in radiators, reducing their ability to heat properly. If they sit idle for months, thermostatic radiator valves (TRVs) can also seize up, reducing performance," he warns.
"Turning the heating on at the right time keeps water moving, prevents these issues and ensures your radiators heat efficiently when winter really hits. Running your system occasionally, even before winter sets in, keeps everything circulating and in good working order."
How long should I leave the heating on for?
Although there isn't a magic formula for the most economical way to use central heating, our experts do agree that slow and steady wins the race.
“There isn’t a one-size-fits-all answer here, as much depends on your property’s size, insulation, and your own lifestyle," agrees Ryan Willdig. "Modern boilers and smart thermostats are designed to maintain steady temperatures more efficiently, so aiming for consistent warmth rather than peaks and troughs will not only keep you more comfortable but also save energy," he says. "It’s about working with your system rather than against it.”
“Programming your smart thermostat properly can help you heat your home efficiently," advises Adam Knight. "Set the thermostat to your target temperature and let it control the call for heat throughout the day, or night. A boiler may only need timed ‘on’ periods around when you’re home. Aim for steady conditions rather than big swings in temperature.”
“Keep it simple and steady," he says. "Set the thermostat to a realistic target – about 18-20°C for most homes during the day – with a small adjustment for nighttime – usually around 16–17°C – rather than switching off.
"If you have TRVs or smart valves, it’s also a good idea to control each room’s heating individually," says Adam. "Warm up rooms that are actually being used, and set unused rooms lower or on a pre-heat setting, ready for when you need them."
You'll also need to adjust this as the seasons change, says Nick Duggan. "In autumn, a couple of hours in the morning and evening usually does the trick. As the weather turns colder, many people prefer a low, steady heat throughout the day."
Personally, I'd certainly recommend using a smart heating system such as the ones offered by Hive. I find it's a great tool for keeping on top of my heating hours, making sure my home doesn't get too cold and being able to understand how much energy I'm using.
Our experts say it's also worth following these extra tips for getting the best from your heating once you've turned it back on:
- Regular servicing to keep your boiler running safely and efficiently, and your boiler’s warranty valid
- Use modern radiators and smart controls as they heat up quickly, hold warmth well and adjust to your schedule without wasting energy
- Adopt simple tricks like closing curtains at dusk and shutting internal doors to keep warmth in
- Make sure you bleed radiators and block draughts in windows and doors
FAQs
Is the advice for when to turn on the heating the same if I have a heat pump?
In general terms, the temperature ranges for inside and outside your home remain the same if you use a heat pump, but there's less work needed regarding when you decide to turn the heating on and off, says Samid Halimi, residential product manager at Daikin UK.
"It’s best not to let your home fall below 18°C," confirms Hamid. "Heat pumps work best when they keep a steady, comfortable indoor temperature rather than being turned on and off in bursts. If your home gets too cold, your heat pump has to work harder to warm it back up, which uses more energy," he warns.
"It’s far more efficient to keep your home gently topped up to the right level. Think of it like keeping water in a flask instead of boiling a kettle from cold every time. Steady warmth is always easier and more economical.
"Heat pumps are designed to run continuously, so there’s no real benefit in keeping them switched off once the weather turns colder," says Hamid. "One of the big advantages of a heat pump is that you can simply set it and forget it: the system will only run when the indoor temperature falls below your chosen level.
"The best approach is to set your thermostat between 20-21°C and let the heat pump do the rest. Don’t keep changing the temperature and keep doors and windows shut to avoid heat loss," he adds, "and if you want to fine-tune your schedule you can use the app to make small adjustments."
Hamid Salimi has a BSc and MSc in mechanical engineering and has worked with Daikin for over 13 years in various roles such as product applications, HVAC design and currently as a Product Manager leading a team of product specialists covering all aspects of residential renewable heating.
If my house temperature is above 18°C but it's colder outside, do I need to turn my heating on?
Of course, if your home is well insulated, you may find even though the temperature outside has dropped, inside you're still feeling pretty cosy. But, should you still be turning your heating on?
“No. Heat for the inside and your thermostat, not the forecast," says Adam Knight, Lead Engineer at BOXT. "If your indoor temperature is comfortable and stable, leave it. Just make sure frost protection is enabled on your boiler and run the system briefly now and then to ensure everything is still running smoothly."
Although he does share a word of caution. "If temperatures are freezing outside and you have an outdoor boiler condensate pipe, one thing to be aware of is that the water in the pipe may freeze and obstruct the flow through your system, stopping your boiler from working properly.”
You may also be wise to give your heating a burst every now and again, even if it doesn't feel that cold.
"It’s smart to run your heating for a short time every few weeks, even in a warm house," says Nick Duggan, director at The Radiator Centre. "It keeps the valves moving and the system in good shape. Think of it as giving your radiators a little workout to stay healthy and responsive."
What's the lowest temperature my house should be?
So how low is too low when it comes to inside temperture?
“For health and comfort, we recommend keeping living areas at about 18°C or above, though 20–21°C suits many older people and young children," says Adam Knight, Lead Engineer at BOXT. "If you’re away, keep the home at least 12–15°C to reduce dampness and protect pipework.”
Of course, while we all have the best intentions of being organised and planning ahead, it's easy to forget when the weather is warm that you'll need your heating at some point. If you're not quite on track and are suddenly worried your boiler may need more than just a service, check the signs it might be time to replace your boiler.
Or, if you're thinking of switching to a totally different system, weigh up the pros and cons of heat pumps vs gas boilers.
