Households warned wrong boiler setting could be costing you £100s

Households across the UK are being urged to check a simple setting on their combi boiler, after experts warned many could be spending far more than necessary to heat their homes this winter. As temperatures drop and energy bills are expected to rise again in the new year, a common mistake with boiler flow temperature settings could be quietly driving up costs for thousands of families.

Most modern homes have a condensing combi boiler, which is designed to run efficiently at lower flow temperatures. However, many are still set at default levels of 70°C to 80°C, far higher than needed. Gordon Wallis, energy expert at Your NRG, explained that adjusting the boiler’s flow temperature can reduce gas usage without turning down the thermostat.

“If your boiler’s flow temperature is set too high, your system will burn more gas than it needs to heat your radiators,” Wallis said.

“By lowering the radiator flow temperature to around 55°C or 60°C, you can often heat your home just as effectively while using less energy.”

The flow temperature controls how hot the water leaving the boiler is before circulating around radiators. Crucially, this is not the same as lowering your thermostat: radiators may take slightly longer to warm up, but the home will still feel just as comfortable.

Advice on social media has recently highlighted the issue, with many energy suppliers recommending lower flow temperatures for better efficiency.

However, Wallis cautions that this adjustment is most effective for homes with combi boilers and reasonable insulation.

He said: “If you have a hot water tank system or an older boiler, check with a qualified engineer first. But for most modern combi boilers, this is a very simple and effective adjustment that households can make themselves.”

While this might be a small change, the cost adds up and could save you £100s in the long run.

Households are also encouraged to check their hot water temperature settings, as many are unnecessarily high.

“If your tap water is so hot you have to add cold water to use it, you’re paying for heat you don’t need,” Wallis added.

With energy costs still a major concern this winter, these simple boiler efficiency steps could help households cut bills without sacrificing warmth.