Is your boiler flue steaming? It could be a sign you're wasting money on energy, expert warns

Watch out for this warning sign as it could save you a lot of money this winter season

A boiler flue
(Image credit: Getty Images/Christopher Furlong)

A steaming boiler flue is normal, right? We're sorry to say if you own a combi boiler and your boiler flue is steaming excessively, then you might just be wasting a lot of money on energy as experts issue a boiler flue steaming warning.

This is worth addressing as we head into the new year with higher energy prices since the energy price cap is set to rise by 5% from 1st January 2024.

But fear not, as there is an easy fix to save energy at home you can perform to stop your flue from steaming and using up unnecessary heat and gas in the process.

A kitchen with a boiler cupboard and bookshelves

(Image credit: Future PLC/Colin Poole)

Boiler flue steaming warning

Firstly, it’s worth pointing out that just a little bit of steam coming out of your combi boiler flue is normal during the winter.

‘An occasional wisp of steam from a combi boiler isn’t anything to worry about,’ says Jon Bonnar, managing director at Cotswold Energy. ‘Steam is also more common in cold weather because when warm air (from your boiler) meets cold air (outside), the moisture condenses – similar to your breath on a cold morning outside.’

But if there are thick clouds of steam being released from your flue, then that could be a warning sign.

A boiler flue

(Image credit: Getty Images/Alan Morris)

‘If your combi boiler is suddenly emitting excessive amounts of steam, it could be a sign that something is wrong. Large plumes of steam could also mean that you’re wasting money, as you’re essentially heating water that, rather than warming up your home, is being released outside,’ Jon continues.

And while there could be a few different reasons for this such as limescale build-up or a faulty pressure relief valve, the most common is the wrong temperature setting on your boiler. And this combi boiler setting change could save you a lot of money. The optimal sweet spot is said to be 60 degrees.

Hallway with geometric black and white floor tiles, large metal radiator, stairway and original cornice

(Image credit: Future PLC/James Merrell)

‘Depending on the combi boiler model, you can usually adjust the boilers flow temperature by opening the flap to reveal the digital display,’ says Danielle Robinson, central heating category manager at Toolstation. ‘Once you’ve done this, you’ll likely see two dials or settings – one which controls the hot water from your taps and the other controls the radiators in your home. You’ll just need to adjust the temperature for the radiators and can usually adjust the temperature slightly – without noticing too much of a difference.’

And just like that you could be saving money on energy, instead of heating the air outside.

News Writer

Sara Hesikova has been Ideal Home’s News Writer since July 2023, bringing the Ideal Home’s readership breaking news stories from the world of home decor and interiors, as well as trend-led pieces, shopping round-ups and more. Graduating from London College of Fashion with a bachelor’s degree in fashion journalism in 2016, she got her start in niche fashion and lifestyle magazines like Glass and Alvar as a writer and editor before making the leap into interiors, working with the likes of 91 Magazine and copywriting for luxury bed linen brand Yves Delorme among others. She feels that fashion and interiors are intrinsically connected – if someone puts an effort into what they wear, they most likely also care about what they surround themselves with.