A Gas Safe Engineer has shared a simple boiler setting change that could help to cut your energy bills. He claims many households in the UK don’t even know it exists
Katie-Ann Gupwell Content Editor
10:06, 14 Dec 2025
The simple tweak could make a difference to your bills (stock image)(Image: Cunaplus_M.Faba via Getty Images)
For those seeking a cosier home and reduced bills this December, there’s a minor adjustment that could yield significant results. Patrick Garner, a Gas Safe Engineer at Heatable, suggests that most households remain unaware of this particular boiler setting, yet understanding it could prove beneficial for your wallet.
All boilers feature a flow temperature setting, which determines how hot the water becomes as it exits your boiler and travels through your radiators. Whilst this is crucial for efficient heating operation, one straightforward modification can work wonders for both your home’s warmth and energy costs, and it’s remarkably simple to carry out.
Patrick cautions that many people’s boilers are configured excessively high straight from the factory, typically ranging from 75°C to 80°C, which can lead to various issues. Nevertheless, utilising a straightforward adjustment can help you achieve substantial savings.
Why it’s important
When a contemporary combi boiler operates with a flow temperature of approximately 60°C, it functions at peak efficiency in condensing mode. This occurs because the boiler extracts more heat from the gas it consumes.
Additionally, you can reduce your gas consumption by as much as 9%, potentially saving roughly £100 annually on average. The brilliant aspect is that your home won’t feel any chillier.
Patrick elaborated: “The house will feel just as warm. Your radiators will heat up a little slower, but they stay warm for longer and keep the temperature steadier. You lose that intense ‘blast’ of heat that wastes gas, and most people won’t even notice it.”
What occurs if it’s set too high or low?
Setting your boiler temperature excessively high (generally beyond 75°C) risks squandering energy, causing radiators to overheat and forcing the boiler out of condensing mode. The rapid temperature shift can also result in a home that feels considerably less comfortable.
Set it too low (beneath 50°C), and you might find it challenging to heat your property during chilly weather. This can prove particularly problematic in older properties with inadequate insulation.
What temperature should you aim for?
Combi boilers ought to be configured at approximately 60°C for the flow temperature. Patrick recommends that system or traditional boilers work best when set at 65°C for heating and a minimum of 60°C for hot water, as this continues to provide protection against Legionella.
There’s more to consider, as Patrick also suggests three swift checks you can carry out this December. These comprise:
- Pressure – your boiler should sit around the 1 to 1.5 bar when cold. If it drops below this, it needs topping up.
- Heating schedule – timers can be used or smart thermostats to ensure you’re not heating up an empty home.
- Insulate exposed pipes – foam lagging for pipes and a jacket for hot water cylinders reduce heat loss. It also helps if you insulate the outdoor condensate pipe to avoid freezing and causing breakdowns in winter.
Patrick’s primary recommendation, however, is to make the straightforward boiler setting adjustment. He explained: “A tiny twist of the dial is all it takes to stay warm for less this December.”
