Is it cheaper to leave your heating on all day? The official answer plus the exceptions you need to know about

The cold always seems to hit hardest in January, and with ice and snow weather warnings out for most of the UK 2025 looks set to be no different. This is also the time of year when the debate over whether it's cheaper to leave your heating on all day starts to do the rounds.

You'll note the use of the word debate. If you've been wondering if it is cheaper to leave your heating on all day, even at a low temperature there are many arguments for and against whether it really is the most efficient way to heat a house. Because houses vary so much, from the heating system to the insulation, there are so many exceptions to the rule. So many in fact that a lot of the energy suppliers we contacted for a comment refused to answer as heating is so subjective.

However, the official line (for a typical home with a boiler) is that it is not cheaper to leave your heating on low all day. 'It’s a common misconception that leaving the heating on all day at a low temperature is cheaper than switching it on only when needed,' explains Dinesh Kumar, a British Gas service and repair engineer. 'In reality, this uses more energy because homes lose heat throughout the day, especially those with poor insulation. '

Why is it not cheaper?

This line is backed by the Energy Saving Trust, the main UK public body for reducing energy use and carbon emissions, which states on its website: 'If you have a boiler....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.'

Heating expert Matthew Jenkins from MyJobQuote.co.uk. agrees saying: 'Your home is constantly losing heat through the walls, windows, and other gaps. Even if your heating is on low, it will still be working hard to replace lost heat. This leads to higher energy consumption.'

He also points out that 'your boiler is designed to work in cycles, turning on and off to maintain a set temperature. When you leave it on all day, it is constantly running. This can be much less efficient and puts more strain on the system.'

When is it cheaper to leave heating on all day?

As we mentioned above there are exceptions depending on your heating system. If your home is heated by a heat pump or a modern condensing boiler that can recover wasted heat, both of these are better suited to leaving on all the time at a low temperature and will result in cheaper bills.

It is also worth noting that if your home uses underfloor heating rather than radiators then it is more economical to leave this on all day when it's particularly cold. In contrast, radiators are better suited to being turned on and off.

The other exceptions to consider are what your home is made out of and how well-insulated your home is. If your home is made from brick, whilst the walls will take a while to heat up, once they have they are very good at retaining and releasing heat back into the house, making them the perfect candidate for low and slow heating. Finally, good insulation including cavity walls and loft insulation will help to keep the heat so leaving the heating on low for longer could be more effective.

What is the most economical way to run your central heating

Working out whether your house is best suited to leaving the heating on all day will most likely come down to trial and error. However, if you live in a house with a boiler and regular radiators here are a few tricks the experts recommend to save energy and money.

1. Set your thermostat between 18°C and 21°C

'As temperatures continue to drop, I recommend setting your thermostat somewhere between 18°C and 21°C to stay comfortable and warm,' says Dinesh Kumar from British Gas.

'Even just a small reduction in your thermostat setting can make a significant difference,' agrees heating expert Matthew Jenkins. 'Aim for a comfortable temperature of around 18 – 20°C during the day and then opt for lower temperatures at night.'

2. Install a smart thermostat

Both Matthew and Dinesh agree that a smart heating system can go a long way towards helping you lower your energy bills.

'The most effective way to heat your home while saving on energy bills is by using smart home heating technology, such as the Hive Thermostat. This allows you to control your heating remotely from your smartphone or tablet and makes sure you're only heating your home when you need to,' says Dinesh.

Matthew adds that with this technology in place, you can schedule your heating for specific times when you need it the most and set lower temperatures when you are asleep or out of the house.

3. Draught-proof windows and doors

'Proper insulation can help to significantly reduce heat loss and can improve the efficiency of your heating system,' explains Matthew. 'Consider insulating your walls, loft, and floors to keep your home warmer for longer.'

However, it's also important to draught-proof windows and doors. This will keep the cold out and the heat in. Go around doors and windows to check for any weak points and consider installing insulation tape. A good old-fashioned draught excluder along the bottom of a door can also help out.

We're sorry that we couldn't give you a clear-cut answer for whether it is cheaper to leave your heating on all day. But if you follow these tips and keep an eye on your energy usage each month you'll soon find what works best for your home.