I’ve been a fan of Kirstie Allsopp's mould hack for a long time - it’s easy, free and has reduced the damp and condensation in my home

Kirstie Allsopp has shared her top tips for banishing mould from your home - and the best thing is it’s completely free to try.

We may be in March, but after last week’s cold snap, the weather certainly doesn’t feel spring-like, and if you’ve been struggling to get rid of damp, mould and condensation, Kirstie’s easy hack could be just what you need.

The method, known as lüften, is a German practice whereby you open all your doors and windows in short bursts as a way of shock ventilation so the cold dry air removes moisture from your home. I use this method and have had great results, but don't take my word for it, the experts agree it's a great free fix.

What's the hack?

Back in January, Kirstie Allsopp took to X (formally Twitter) to praise a video shared by Which? Which celebrated the practice of 'Lüften' and ‘Stoßlüften’ to reduce mould in your homes. In her reply to the post, she stated that she wanted more people to be aware of simple solutions such as: ‘opening your windows daily’ to reduce dampness.

We’ve also known this method as burping your home, and it’s well known for its effectiveness. The method is also simple to follow, requiring no money and little time on your part—making it an easy solution we all can take part in.

‘Instead of leaving windows slightly open all day, which doesn’t do much to reduce humidity and can waste heat, this method involves opening all your windows wide for just a few minutes, then closing them again,’ explains Stephen Day, Heating Engineer at iHeat.

‘It works by quickly flushing out warm, damp air from your home and replacing it with drier air from outside. Since warm air holds more moisture, this simple trick helps to lower humidity levels fast, stopping condensation before it can settle on windows and walls.’

Should you use this hack?

‘Proper ventilation and humidity control play a key role in preventing and managing black mould,’ says Dr Jonathan Kirby, developmental chemist and mould expert at Dryzone. ‘It’s only natural to want to seal in the heat but to reduce humidity you also need to make sure your home is well-ventilated while heating it. This will allow old, damp air to circulate out of the home and replace it with fresh, dry air.’

I have been using this method to keep my home mould-free for a while now. First thing in the morning, I always blast my windows open for 10 minutes and I have seen a reduction in condensation and mould in my home - especially in my bedroom and around windowsills. Now, I am planning on investing in one of the best dehumidifiers, but the main draw of Kirstie’s method is that it is completely free, so I won't be saying goodbye to it anytime soon.

‘It’s a great free fix that can help prevent condensation and mould, and it’s widely used in places like Germany for a reason. That said, we know that people are mindful of energy use, and some might be worried about wasting energy,’ says Stephen.

‘The key is to keep the windows open for just five minutes - long enough to let the stale air out but not so long that your home loses too much warmth.’

If you have existing mould, while it is helpful to continue practising this tip, you should also deal with the source directly and clean the mould off. We’ve rounded up our top products for banishing existing mould.