The boiler tweak that can save on heating for families with small children

Mike Fell
3 min readDec 8, 2021


Turn off the lights? Do the washing at 30°C? There are lots of common ways we save energy. But there’s a less well-known approach that is getting attention right now, and it could be particularly helpful for families with small children.

This winter, many people have started checking the “flow temperature” on their boilers. This is different from the temperature you set on the thermostat. Instead, it means the temperature which the boiler sends water out to your radiators.

Incredibly, many boilers heat radiators up much too hot. This not only makes them waste energy, but the radiators and pipes pose a risk of burns to little hands and feet. You’re also more likely to end up with overheating at times, which can make it hard for children and adults to sleep.

Turning down the flow temperature on your boiler can help it catch more of the energy from the burning gas, meaning you need less gas to heat your home. In fact, this simple tweak could save as much as 8% on your gas use — and therefore save money and carbon emissions too.

The important thing is that your actual room temperature doesn’t change. Your central heating still heats your home to 21°C or whatever you set it to — although it will take a bit longer. This last bit is why it is especially good for families with children.

No longer burning, but still warm — and more efficient. Credit: Becky Stern

Homes with children are more likely to be heated constantly during the day. This means your home only has to heat up once, then your heating can tick over all day with its new more efficient way of running.

Not only that, but because your radiators are no longer scalding hot, there’s less of a chance for children to get burned.

So how do you turn down your flow temperature? It varies from boiler to boiler. Luckily, the organisation Nesta have put together a simple tool to help you. It will talk you through the process and, importantly, let you know if you boiler is suitable (not all are).

Remember, when you have turned down he flow temperature your heating will probably take longer than usual to heat up, so you may need to put it on a bit earlier. Give it a try and see how it works out. If it just isn’t reaching the temperature you want it to you may need to turn the flow temperature back up a bit. And be sure to monitor closely if anyone in the home has health conditions that make it important they stay warm.

Good luck and stay warm!

To write this article I drew on detailed guidance is available from The Heating Hub — check it out! [I updated this article 25 Aug 2022 to add reference to the new Nesta tool!]



Mike Fell

Researcher on energy flexibility at @UCL_Energy by day. Also interested in art and open science.