How your Boiler Flow Temperature could be Costing You Money

If you’ve ever wondered, “What is boiler flow temperature?” you’re not alone – and you’re likely not the only one missing out on an opportunity to save money on energy bills.

Boiler flow temperature is a crucial yet often overlooked factor that directly impacts the efficiency of your home’s heating system.

It’s the temperature to which your boiler heats water before circulating it through your radiators, taps, or shower.

Despite its importance, many modern boilers come pre-set at around 80°C, a level that’s far too high, particularly for combi boilers.

Heating experts warn that running your boiler at this default setting could be causing you to overpay on your energy bills.

By lowering the boiler flow temperature to around 60°C, you can help your boiler work smarter, not harder.

This allows it to enter “condensing mode”, a state in which it recovers and reuses leftover heat, making your heating system more energy-efficient.

With energy costs continuing to rise, checking and adjusting your boiler flow temperature could be one of the simplest and most effective ways to cut back on unnecessary expenses.

What Should the Boiler Flow Temperature Be?

Most boilers are pre-set at 80°C. In actual fact, the temperature should be about 20-30°C lower.

You can find your boiler flow temperature on your boiler’s temperature controls and this can be adjusted using the buttons or dials.

But if you’re not sure where yours is, it is best to look at your boiler’s manual.

However, there are instances where you shouldn’t do this.

Nicholas Auckland, of Trade Radiators, explained:

“If you have a boiler with a hot water tank, then you shouldn’t touch your boiler’s flow temperature.

“This is because turning it down too low can make drinking water unsafe.”

In this instance, keep your hot water tank temperature between 60°C and 65°C, as this will be hot enough to kill off any bacteria.

Why Should you Reduce your Boiler Flow Temperature?

Reducing your boiler flow temperature is better for your boiler’s overall efficiency.

But that is not the only reason why you should do it.

It will lower energy bills

While there are ways to heat your home without switching on the heating, most people will need to use their boiler at some point.

By lowering your boiler flow temperature, you can reduce energy usage and, in turn, lower your heating bills.

Many boilers are set unnecessarily high, forcing them to work harder to heat water.

Adjusting the flow temperature to 60ºC could cut gas usage by 9%, while dropping it further to 55ºC could save up to 12%.

This simple change could save you as much as £65 a year.

It puts less strain on the boiler

Replacing a boiler can set you back thousands, so it’s well worth keeping yours in top condition.

Regular servicing is key, but so is making sure your boiler isn’t working harder than it needs to.

One simple way to protect your boiler and boost its efficiency is by lowering the boiler flow temperature.

This helps it operate at its ideal capacity rather than straining to reach unnecessarily high temperatures.

That said, it’s always smart to recognise the signs of when a replacement might be needed—just in case your boiler has reached the end of its road.

It won’t affect daily life

Unless your home is losing heat and desperately needs draught-proofing, lowering your boiler flow temperature slightly won’t have much impact on your daily comfort.

In fact, most experts agree you’ll hardly notice the difference.

That said, if someone in your household is vulnerable to the cold, it’s best to avoid setting the flow temperature below 60ºC, as it could slow down how quickly your home heats up.

For most households, keeping the boiler flow temperature between 50-60ºC is the sweet spot.

You’ll still enjoy warm, cosy rooms and hot showers—all while saving on energy bills. It’s a small adjustment with big benefits.