As energy prices rise across the UK, many households are asking the same question: “Is it cheaper to leave the heating on all day at a low temperature, or switch it on and off when I need it?”

There is a lot of conflicting advice online, but the answer is actually quite clear for most UK homes: in general, it is not cheaper to leave your heating on all day. You normally save more by only heating your home when you need it, and by using your controls properly.

Below we explain why, how this applies to typical UK properties, and share easy practical steps to keep your home warm and your bills down.

Why leaving the heating on all day usually costs more

Every building constantly loses heat through the walls, roof, windows, floors and draughts. The higher the difference between your indoor and outdoor temperature, the faster that heat loss happens.

If you leave your heating on all day, even at a low setting, your boiler or heat source is working to replace heat that escapes all the time. Over many hours, this almost always uses more energy than turning the heating off when you don’t need it, especially overnight or when you are out.

When you switch the heating on later, your system may work harder for a short time, but the total energy used over 24 hours is normally lower than keeping the house warm continuously.

UK energy experts: what do they say?

Organisations such as the Energy Saving Trust and most independent heating engineers agree on this point: it’s generally more efficient and cheaper to use your heating only when you need it.

Their advice is to combine good insulation with a room thermostat, thermostatic radiator valves (TRVs) and a programmer or smart heating control, so you keep comfortable without wasting energy.

When could leaving the heating on be an exception?

There are a few limited situations in UK homes where leaving heating on for longer periods may make sense:

• Highly insulated, airtight homes – for example, modern eco-homes or properties built to Passivhaus standards. Heat loss is so low that running heating at a very low background level may be similar in cost to short bursts.
• Electric storage heaters – many older flats with storage heaters use Economy 7 or time-of-use tariffs. In these cases, heaters charge up at night on cheaper rates, then release heat slowly during the day. Here, the question isn’t about leaving heating on all day, but about using off-peak electricity correctly.
• Vulnerable occupants – for very young babies, elderly residents or those with health conditions, maintaining a more consistent indoor temperature can be more important than maximising savings. Even then, insulation and efficient controls still help reduce bills.

For the vast majority of typical UK homes with gas combi boilers or conventional wet heating systems, however, leaving the heating on all day is not the cheapest way to run it.

How to run your heating efficiently in the UK

Instead of leaving your heating on constantly, focus on smart control and basic home improvements. Here are the key areas that make the biggest difference.

1. Use a programmer or timer

Almost all modern boilers have a built-in timer or are connected to a wall programmer. Use it to schedule heating around your routine:

• Morning – set the heating to come on 30–45 minutes before you wake up.
• Daytime – turn it off or down if the house is empty.
• Evening – bring the temperature back up for when everyone is at home.
• Night – switch it off or reduce the set temperature while you’re in bed.

This approach minimises wasted heating while still keeping your home comfortable when you actually need it.

2. Set your room thermostat correctly

A common myth is that setting your thermostat higher will heat your home faster. It won’t – it just tells your boiler to keep running until your rooms reach a higher final temperature, using more gas or electricity.

In most UK homes, a thermostat setting of around 18–21°C is comfortable and efficient. Try starting at 20°C and adjusting slightly downwards to see the lowest temperature you are still comfortable with.

3. Take control of individual rooms with TRVs

Thermostatic Radiator Valves (TRVs) let you set different temperatures in different rooms. This is ideal if you:

• Don’t use certain rooms every day
• Prefer bedrooms cooler than living spaces
• Work from home in just one or two rooms

Turn TRVs down but not fully off in rarely used rooms to reduce energy use while preventing damp or mould.

4. Improve insulation and reduce draughts

The better your home is insulated, the slower it loses heat, meaning your heating system can run for shorter periods and still maintain comfort.

Priority areas for most UK homes include:

• Loft insulation – topping up to around 270mm can significantly cut heat loss.
• Cavity wall insulation – common in houses built after the 1920s.
• Draught-proofing – sealing gaps around doors, windows, floorboards and chimneys.
• Double or triple glazing – or at least good quality secondary glazing.

These improvements not only reduce bills now but also make your home more comfortable in winter and summer alike.

5. Consider smart heating controls

Smart thermostats and smart TRVs can make it easier to heat only the rooms you use, only when you use them. Many systems allow you to:

• Control heating from your smartphone
• Use geofencing to turn heating down when you’re out
• Schedule heating for different days of the week
• Monitor your energy use in real time

While smart controls don’t magically cut bills on their own, they make it much easier to avoid waste, especially in busy households with changing routines.

Running costs: all day vs timed heating

Every property is different, but the principles are the same. Below is a simplified comparison to illustrate why constant heating usually costs more.

Remember: leaving heating on all day only becomes competitive if your home is so well insulated that heat loss is extremely low – something that doesn’t apply to the majority of UK housing stock.

Balancing comfort and savings

The goal isn’t to live in a freezing house. It’s to use energy where it actually benefits you. A good approach in the UK climate is to:

• Heat the rooms you use, when you use them.
• Keep a comfortable but not excessive thermostat setting.
• Improve insulation and draught-proofing over time.
• Upgrade to efficient heating controls when you can.

This balances day-to-day comfort with meaningful long-term savings.

Common myths about home heating in the UK

“My boiler uses more gas when it starts up, so it’s cheaper to leave it on”

Modern condensing boilers are designed to modulate – they automatically adjust how hard they work. Any small extra burst of energy at start-up is tiny compared with the energy lost by keeping your home warm all day when you’re not there.

“Turning the heating off causes damp and mould”

Damp and mould are mostly caused by excess moisture and poor ventilation, not simply by turning the heating off. Keeping your home reasonably warm does help, but so does:

• Using extractor fans in kitchens and bathrooms
• Drying clothes outside or in a ventilated space where possible
• Fixing leaks and improving insulation

You do not usually need constant heating to prevent damp; you need a balanced approach to warmth, ventilation and humidity.

“Electric heaters are always cheaper than the gas central heating”

In the UK, gas is normally much cheaper per kWh than standard-rate electricity. Portable electric heaters can be useful for a single room, but running several of them for hours can be more expensive than using an efficient gas boiler with properly controlled radiators.

Simple, low-cost tips to cut your heating bills

Alongside better control of when your heating is on, these small changes can add up:

• Bleed your radiators so they heat up evenly.
• Use radiator reflector panels on external walls to reflect more heat into the room.
• Keep radiators clear – avoid blocking with sofas or heavy curtains.
• Shut doors to keep heat in occupied rooms.
• Close curtains at dusk to reduce heat lost through windows.
• Use draught excluders on doors and letterboxes.

Thinking about upgrading your heating system?

If your boiler is old or your controls are basic, upgrading can make your home more efficient, more comfortable, and cheaper to run.

Small changes to how you use your existing system often deliver immediate savings, while larger upgrades can lock in benefits for years to come.

Summary: should you leave your heating on all day?

For typical UK homes with standard insulation and gas central heating, the answer is no – it’s usually not cheaper to leave your heating on all day. You’ll almost always save more by heating your home only when you need it and by using your controls wisely.

Focus on timers, thermostats, TRVs, insulation and smart controls to stay warm without wasting energy. Over the heating season, these changes can make a noticeable difference to your bills.