As households across the UK prepare for colder months, financial adviser Martin Lewis is once again drawing attention with simple, data-backed guidance on how to cut back on heating bills. Amid persistent concerns over the cost of living and rising energy prices, even small adjustments to home heating systems could lead to real savings, particularly for homes equipped with combi boilers or traditional hot water cylinders.
Small Temperature Changes Could Yield Noticeable Savings
Martin Lewis, founder of the Money Saving Expert website, is known for delivering practical financial advice rooted in everyday life. This season, he has turned his attention to thermostat settings. Drawing on figures from the Energy Saving Trust, he explains that lowering your thermostat by just one degree can lead to a saving of around £90 per year for a typical household.
Many homes in the UK set their thermostats in the low 20s by default. However, adjusting from 21°C to 20°C could deliver significant benefits without a major loss of comfort for healthy adults. In fact, the World Health Organization recommends a standard indoor temperature of 18°C, with slightly higher temperatures advised only for elderly people or young children.
This small behavioural shift reflects the kind of low-cost, high-return decision-making that Lewis consistently promotes. In a context where energy prices remain unstable and bills continue to eat into household incomes, such practical tips are more relevant than ever.
Tweaking Boiler Settings: The Case for Flow Temperature Control
While lowering the thermostat is a well-known energy-saving technique, Lewis highlights another overlooked opportunity: adjusting your boiler’s flow temperature. This refers to the temperature of the water your boiler sends to your radiators. For homes with a combi boiler—the most common type in the UK—this setting is often too high by default.
According to the Express, the Money Saving Expert team states:
“Combi boilers work best when they heat radiators to 60°C or below. But this flow temperature is often set much too high, often between 70°C and 80°C.”
This setting can be manually lowered, and doing so could reduce your gas bill by up to £65 a year, according to Lewis. The benefit comes from improving the boiler’s efficiency—operating at a slightly lower flow temperature allows the system to work more steadily and less aggressively, using less fuel over time.
For those without combi boilers—such as homes with a hot water cylinder—the advice changes slightly. These systems must keep water at 60°C or higher to avoid the risk of legionella bacteria, according to guidance from the Health and Safety Executive. In such cases, experts recommend setting the cylinder temperature to 70°C to account for heat loss between the boiler and the tank. Adjustments to these systems should always be made with the help of a Gas Safe-registered engineer.
Adapting Heating Habits Without Compromising Comfort
One of the reasons this advice resonates is because it challenges a common perception: that warmth equals speed and intensity. Many people turn their heating on full blast expecting fast results, but Martin Lewis suggests a smarter route—gradual and consistent heating at lower temperatures.
This approach not only reduces fuel use but also puts less stress on heating systems, potentially extending their lifespan. And for many households, these adjustments require no investment in new equipment—just a better understanding of the settings already available.
Most homes operate with boiler presets left unchanged since installation. These defaults are often too aggressive, aimed at maximum output rather than energy efficiency. Lewis’s advice encourages homeowners to take more control over their own systems, reducing reliance on high-energy defaults and creating a more cost-conscious heating routine.
In a time when energy bills are rising disproportionately for low and middle-income families, these behavioural adjustments can have a strong financial impact without sacrificing comfort.
