How to get more efficiency from your combi boiler

Lower the flow temperature: most combi boilers are set to 80°C from the factory. Dropping this to 60–65°C increases efficiency with minimal impact on comfort in well-insulated homes, and can trigger "condensing mode" more often, which extracts extra heat from flue gases.

Balance your radiators: if some rooms are much hotter than others, your system is working harder than necessary. Balancing adjusts the lockshield valves on each radiator so heat is distributed evenly.

Fit a room thermostat and TRVs if you don't have them — heating only the rooms you're using can cut bills by 10–15%. Smart thermostats like Hive or Nest add further savings through learning schedules.

Insulate your pipework: lagging exposed hot water pipes (especially in the loft or garage) retains heat and reduces the time it takes to get hot water at the tap.

Bleed all radiators annually and check for cold spots — a system full of air or sludge runs much less efficiently and the boiler works harder to compensate.

Get the boiler serviced annually: a poorly combusting boiler can be 10–20% less efficient than one that's been properly set up. An engineer can check and adjust gas pressure and combustion settings.

Check your boiler's ErP rating label if it was installed recently — if it's below A-rated and the boiler is over 10 years old, a new A-rated condensing boiler could save £200–£350/year in gas bills.