Adjusting a single boiler setting this July can help cool down your home and lower your energy bills, according to gas safe engineer Patrick Garner from Heatable. Many UK households with combi boilers are unknowingly using gas even with the heating switched off, contributing to indoor heat and higher costs.
Why Your House May Be Hot
If your home has a gas combi boiler, it may still be pumping heat into your property even with the heating off. The culprit is the hot water settings. Every time you take a shower, turn on a hot tap, or wash dishes, the boiler fires up. Although each burst is brief, the boiler releases heat through its casing, pipework, and flue, adding to the overall warmth inside your home. "Once the heating is off, hot water becomes the main thing still using gas," Patrick explained. "And in homes with several people showering every day, the cost soon adds up."
What You Need to Check
First, ensure your boiler is set to hot-water-only mode. Leaving both heating and hot water enabled could trigger the heating unexpectedly during a cold spell or due to a badly placed thermostat. Next, check the hot water temperature on the boiler itself. For combi boilers, around 45°C to 50°C is typically comfortable for taps and showers. "Importantly, this only applies to combi boilers. If your home has a hot water cylinder, do not reduce the stored water temperature below 60°C to avoid the risk of Legionella," Patrick warned.
Disable Pre-Heat Mode
Finally, check whether your boiler has pre-heat or comfort mode activated. This setting maintains a small quantity of water warm inside the boiler so hot water arrives at the tap faster, but it causes the boiler to fire repeatedly throughout the day, even when nobody is using hot water. "Pre-heat mode constantly adds heat to your home and inflates your bills," Patrick said.
Extra Tips to Cut Costs
Leaving washing up for one big wash at the end of the day can eliminate those brief bursts of heating that contribute significantly to your bills. Repair any dripping hot taps—this not only reduces your gas bill but also your water bill. Avoid unnecessary upgrades: solar diverters, for instance, only make sense if you already have solar panels, a hot water cylinder, and an immersion heater; they are of no use with a standard combi boiler.
Patrick concluded: "You pay a standing charge of around 30p a day for being connected to the gas network, so you'll never get your bill down to zero. But a few changes can make a big difference overall."
