How to Lower Your Heating Bills Without Feeling the Chill: Try Adjusting Your Boiler Flow Temperature

If you’re looking for a low-cost way to cut your heating bills without sacrificing comfort, tweaking one setting on your boiler could be the answer. It’s a change many people don’t realise they can make, but it can lead to noticeable energy savings, especially if you have a modern condensing combi boiler.

If you’re based in Lancashire and have a combi boiler, read on to learn how a simple tweak could reduce your gas bill by up to 8% – without compromising on comfort.

What is Boiler Flow Temperature?

Boiler flow temperature refers to the temperature of the water that your boiler heats up before it sends it through your radiators. This is not the same as your room thermostat setting.

• For example, you might set your thermostat to 19°C – that’s the air temperature you want inside.
  
• But to get your rooms to 19°C, your boiler might be heating water to 75-80°C by default.
  
• That hot water flows through the radiators, warming the room. When the air reaches the set temperature, the thermostat switches off the heating.
  

This means your boiler is working harder than it needs to – especially if you live in a well-insulated home. Reducing the boiler’s flow temperature means it uses less gas to maintain a comfortable home.

Why Lowering Flow Temperature Saves Energy

Most modern combi boilers are condensing boilers, which means they can recover heat from their own exhaust gases. But here’s the catch – they can only do this efficiently if the return temperature (water going back to the boiler from the radiators) is below about 55°C.

If your flow temperature is too high (e.g., 80°C), the return temperature stays high too – and your boiler can’t condense effectively. Lowering the flow temperature to around 60-65°C makes it much more efficient.

Potential Savings:

• 6-8% reduction in gas bills
  
• Up to 5-10% extra savings if you turn off your combi boiler’s pre-heat mode
  
• Less strain on your boiler – helping it last longer
  
• Lower carbon emissions – better for the planet!

Is My Boiler Suitable?

This works best if you have a combi boiler, which heats water on demand and doesn’t use a hot water tank. These boilers:

• Let you set separate temperatures for radiators and tap water
  
• Are common in homes built or updated after 2000
  
• Allow easy adjustments via a digital display or dial
  

For homes with a system or regular boiler (which use a hot water cylinder), it’s a bit different. You’ll want to keep the flow temperature at least 65°C to avoid the risk of Legionella bacteria in your stored water. Always check with a heating engineer before making changes.

If you have a combi boiler, here’s how you can give this a try:

1. Locate your boiler controls – Look for two temperature dials or digital settings:
   
   • One for radiators (often shown as a radiator icon)
     
   • One for hot water (tap icon)
     
2. Lower the radiator setting to 60-65°C.
   
3. Monitor your home over a few days. If it still feels warm, great! You might even try reducing it a little further.
   
4. If it feels chilly, increase slightly – the goal is to find the lowest comfortable setting.

Top Tips:

• Take a photo of your original settings in case you need to revert.
  
• Only adjust the radiator temperature – not the hot water temperature unless you know it’s safe to do so.
  
• If you’re unsure about your settings, ask your installer or check your boiler manual.

Adjusting Flow Temperature With the Seasons

For even more savings, you can vary your flow temperature based on outdoor weather:

• Mild weather: Try 50-55°C
  
• Cold snaps: Increase to 60-65°C
  
• Very cold weather: Go higher if needed to maintain comfort
  

Some modern boilers come with weather compensation controls that do this for you automatically. 

Other Upgrades That Work Well With Flow Temperature Reduction

Lowering your flow temperature works even better when paired with smart heating controls and insulation. Consider:

• Thermostatic Radiator Valves (TRVs) – control the temperature of individual rooms
  
• Smart thermostats – learn your habits and optimise heating automatically
  
• Insulation – keeps the heat in so you don’t need to run the boiler as long or as hot

Small Tweak, Big Difference

Lowering your boiler flow temperature could be one of the simplest and most cost-effective steps you take toward a warmer, more energy-efficient home.

Give it a go this week – and see if you notice the difference in your comfort and your next energy bill.

Not Sure Where to Start? We’re Here to Help.

At Greener Homes in Lancashire, we offer free and impartial advice to help you heat your home more efficiently. If you’re not sure:

• What type of boiler you have
  
• Whether your home is suitable for flow temperature adjustments
  
• How to safely make changes
  

…we’re just a call or message away.

Book a free 1-to-1 chat with one of our advisors and we’ll walk you through it step-by-step.

Not Sure Where to Start? We’re Here to Help.