Households urged to make one simple boiler to 60°C setting change to cut energy bills this December

UK households are being encouraged to check a little known boiler setting that could help reduce energy bills this winter, without making homes feel colder.

A Gas Safe registered engineer has said many boilers are set too high by default, meaning households may be wasting gas without realising it. A small adjustment, he says, could lead to noticeable savings during the coldest months of the year.

Patrick Garner, a Gas Safe Engineer at heating firm Heatable, explained that most boilers have a flow temperature setting that controls how hot water is as it leaves the boiler and circulates through radiators.

While the setting plays a key role in how a home is heated, he said many people are unaware it exists or do not realise it can be adjusted.

Households urged boiler flow temperature matters

According to Mr Garner, many boilers are factory set between 75C and 80C. While this ensures fast heating, it is often far higher than needed and can significantly reduce efficiency.

Modern combi boilers work most efficiently when the flow temperature is set to around 60C. At this level, the boiler operates in what is known as condensing mode, allowing it to recover more heat from the gas it burns.

Running at this lower temperature can reduce gas use by up to 9 percent, saving the average household around £100 a year, without sacrificing comfort.

“The house will feel just as warm,” Mr Garner said. “Radiators may take slightly longer to heat up, but they stay warm for longer and keep temperatures steadier. You lose that intense blast of heat that wastes gas, and most people won’t even notice the difference.”

What happens if the setting is too high or too low?

If the flow temperature is set too high, typically above 75C, radiators can overheat and the boiler may stop condensing properly. This leads to wasted energy and can make indoor temperatures feel less comfortable due to rapid heat spikes.

On the other hand, setting the temperature too low, below around 50C, can make it harder to heat a home during colder weather. This is particularly an issue in older or poorly insulated properties.

Recommended boiler settings

For most homes with a combi boiler, engineers recommend setting the flow temperature to around 60C.

For system or conventional boilers, Mr Garner advises setting the heating flow temperature to about 65C, while keeping hot water at a minimum of 60C. This ensures good efficiency while maintaining protection against Legionella bacteria.

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Three quick winter boiler checks

Alongside adjusting the flow temperature, Mr Garner recommends carrying out a few simple checks during December:

• Boiler pressure should be between 1 and 1.5 bar when the system is cold. If it drops below this, the boiler may need topping up.
• Heating schedules should be reviewed to avoid heating an empty home. Timers or smart thermostats can help control this.
• Pipe insulation can reduce heat loss. Foam lagging on pipes and jackets on hot water cylinders help retain warmth. Insulating outdoor condensate pipes can also prevent freezing and winter breakdowns.

Despite these extra steps, Mr Garner said the biggest impact comes from adjusting the boiler’s flow temperature.

“A tiny twist of the dial is all it takes,” he said. “It is one of the easiest ways to stay warm for less this December.”