Millions of households across the UK could cut their annual heating costs by up to £65 with a simple, seconds-long adjustment to their boiler, according to leading supplier Octopus Energy.
The Simple Switch to Lower Energy Bills
This practical advice comes at a critical time, as consumers face rising energy costs. The regulator Ofgem increased its price cap by 2% for the period from October to December 2025, followed by a further 0.2% rise in January 2026. Against this backdrop, any measure to improve efficiency is welcome.
Octopus Energy, referencing analysis from the innovation charity Nesta, suggests that the key lies in your boiler's 'flow temperature'. This is the temperature of the water as it leaves your boiler to heat your radiators, and it is a completely different setting from your room thermostat.
"Set your flow temperature to between 55 and 60 degrees on your combi boiler," the firm advises. "Take a look at Nesta's Money-Saving Boiler walkthrough to see how, depending on your boiler, you could save £65."
Understanding Your Boiler's Settings
Many homeowners are unaware of this setting. If you set your room thermostat to, for example, 19°C, your boiler will heat water to its preset flow temperature before circulating it until the room reaches the desired warmth. Research by consumer champion Which? indicates that a typical boiler's flow temperature is often set unnecessarily high, between 75°C and 80°C.
By reducing the flow temperature to the recommended 55-60°C range, your boiler can operate more efficiently, using less gas while still adequately heating your home. The exact savings will depend on factors like your home's insulation and size, but the potential for reduction is significant.
How to Adjust Your Boiler Correctly
The Energy Saving Trust offers clear guidance for different boiler types. For a conventional boiler with a hot water cylinder, there is usually just one dial to adjust for the heating flow temperature.
If you have a modern combi boiler without a cylinder, you will likely find two settings: one for hot water (often indicated by a tap icon) and one for radiators (a radiator icon). You need to adjust the radiator setting.
Important safety tip: Before making any changes, take a photo or note of the original settings so you can revert if necessary. The simplest approach is to lower the flow temperature gradually until you find the lowest comfortable level for your home and leave it there.
For personalised advice, Nesta, which runs the Money Saving Boiler Challenge, provides a quick online test on its website. This tool can help you determine the best action for your specific system in just a few minutes.
With energy prices remaining a major concern for family budgets, this straightforward adjustment represents a rare win: a no-cost, immediate action that can lead to tangible savings on your energy bills throughout the year.
