Around 7.5 million UK households could save £57 a year on their gas bills by changing one setting on their combi boiler, new research suggests.
Research foundation Nesta says some boilers heat water for radiators to a higher temperature than needed. Lowering it could reduce wasted energy. It costs nothing to check.
But the saving is not guaranteed. The advice is not right for every boiler.
Nesta also estimates that six free changes to home heating could save around £220 a year in total.
Ofgem’s energy price cap increased by 4% on 1 October 2026.
For a typical household paying by Direct Debit on a standard variable tariff in England, Scotland or Wales, that works out at £1,723 a year if the rates stayed the same for 12 months.
The £57 estimated boiler saving is almost as much as the £60 annual increase. But neither figure tells you exactly how much your own bill will change.
Our October energy price cap guide explains the changes in more detail.
Who could save £57?
Many condensing combi boilers are set to send water to radiators at 75°C or 80°C. This is called the central heating flow temperature.
Nesta estimates that lowering a suitable boiler from 75°C to 60°C could cut a household’s overall gas use by around 7%.
At a lower setting, the boiler can use more of the heat it produces. But the saving is not all down to better efficiency.
The Energy Saving Trust says some of the reduction in gas use may come from rooms taking longer to warm up. They might not get quite as warm, either.
The £57 estimate comes from a 2022 experiment at the University of Salford’s Energy House. Nesta recalculated the results using 2026 gas prices and average household gas use.
£57 a year works out at about £4.75 a month. But that does not mean your Direct Debit will fall by £4.75 every month. Most savings would happen when you use the heating.
Your saving will depend on your boiler, its current setting and how much gas you use. If it is already set to around 60°C, you might not save anything extra.
Check your boiler type first
A combi boiler normally heats your radiators and provides hot water to your taps. It does not have a separate hot water cylinder.
On our Ideal boiler, the dial with the radiator symbol controls the central heating water temperature. The dial beside it selects the boiler’s operating mode.
Boiler controls vary between models, so don’t copy the dial positions shown in our photograph. Check the instructions for your own boiler before making any changes.
Nesta is talking about the radiator setting. Do not change the tap-water setting by mistake.
If you have a separate hot water cylinder, do not follow the 60°C combi boiler advice.
The Energy Saving Trust says conventional boilers with hot water cylinders should have a flow temperature of at least 65°C. This helps the stored water reach a safe temperature and reduces the risk of harmful bacteria.
If you are unsure which boiler you have, check the manual. You can also ask a Gas Safe registered heating engineer before changing anything.
How to check the setting on a combi boiler
- Read the instructions for your boiler’s make and model. Check that the flow temperature can be adjusted by hand.
- Find the radiator control. It could be a dial or an option on a digital screen.
- Take a photograph of the current setting. That way, you can change it back if needed.
- If your instructions allow it, lower the flow temperature gradually towards 60°C.
- Check that your home still gets warm enough. Raise the setting if rooms take too long to heat up or stay too cold.
Some heating systems adjust the flow temperature automatically. If you cannot identify the right control, do not guess.
You may need to increase the setting again during colder weather, even if 60°C works well at other times.
What about the £220 saving?
Nesta says households could save around £220 a year by combining six free changes. These are:
- Lower the combi boiler flow temperature towards 60°C, if suitable.
- Turn off hot water pre-heat on a combi boiler that has this feature. You may have to wait longer for hot water.
- Turn down radiator valves in rooms that can be kept cooler. Check the instructions, as valve numbers differ.
- Lower the room thermostat from 20°C to 19°C, if the home stays warm enough.
- Close curtains at night to reduce heat loss through windows.
- Use the heating for a shorter season when the weather is mild enough. Do not rely on a fixed switch-off date.
The £220 estimate includes the £57 boiler saving. It is not another £220 on top.
These are estimates, not promises. You may save less if you already use some of these measures.
Skint Dad says:
With energy bills rising again, it’s encouraging to see a way some households could save money without having to spend anything first.
But the £57 saving isn’t guaranteed, and it won’t apply to everyone.
Small changes like this can help families keep their bills down. However, they don’t change the bigger problem that heating our homes remains expensive.
Do not let your home get too cold
The NHS advises keeping rooms you use regularly at a comfortable temperature. Ideally, they should be at least 18°C where possible.
Some people need a warmer home, particularly if they have health conditions.
If a lower setting leaves you cold, turn it back up. Cutting your heating at the expense of your health is not a saving worth making.
If you cannot afford to heat your home, our guide to free winter warmth help explains where to find support.
Where to get help checking your boiler
Nesta’s free Money Saving Boiler Challenge explains how to check whether lowering your combi boiler’s flow temperature could help you save money.
Before changing anything, check your boiler’s make and model and follow the manufacturer’s instructions. If you’re unsure, leave the setting alone.
