UK homeowners could lower their heating bills by adjusting the flow temperature on their condensing boiler, a simple and free modification. Experts say that many boilers are set too high by installers, often at 70-75°C, which is higher than most homes need.
Condensing boilers operate most efficiently at lower flow temperatures. Ian McLaren, co-founder of Dwellow, a renewable heating provider, explained: "Condensing boilers stop condensing above 70°C, which can reduce efficiency by around 10%. Simply lowering the flow temperature to the lowest comfortable level, often around 50°C, helps the boiler operate more efficiently, uses less gas, and reduces running costs."
For traditional boilers, adjustments can also be made, but temperatures must not drop below 65°C to ensure safety and prevent risks such as legionella. The Energy Saving Trust estimates that households could cut bills by nearly 9% by tweaking the flow temperature, though savings vary based on individual settings.
Additional advice for optimising home heating includes using on/off cycles for well-insulated homes with traditional boilers, while air-source heat pumps perform best with steady, low-level temperatures. Smart thermostats can tailor heating by room and time to maximise efficiency.
The UK government is promoting heat pumps as a key technology for decarbonising heating, aiming for 600,000 installations per year by 2028. Heat pumps can be three times more energy-efficient than gas boilers, helping reduce carbon footprints and save on bills.
