As colder weather settles in and households shut their windows to keep warm, condensation begins to creep back into homes across the UK. What starts as a thin layer of moisture on the inside of the glass can quickly turn into a bigger problem, damp sills, black mould, peeling paint and damage to wooden frames.
One homeowner took to Reddit desperate for solutions, asking what products actually work, as condensation gets trapped inside double-glazed windows causing it to get “drenched and mouldy.” They said: “How to stop this condensation? What products help with this? The black line between the sill and the glass is drenched and mouldy.”
Among the replies, one stood out, a comment from a painter who deals with the damage firsthand and says there is only one device that reliably solves the problem.
“I’m a painter who is regularly called to deal with mouldy windows from this issue. Dehumidifier is the answer,” they said.
According to the painter, homeowners shouldn’t be put off by the idea of constantly emptying water tanks. “You don’t need to empty buckets every day, just run it to your basement drain (if you have one) with a piece of tube or hose.”
They also urged people to remove excess moisture from the air before it has a chance to settle, adding that older ventilation systems often make the problem worse.
“Upgrade your bathroom fans if they are old, the more moisture you can get out of the house the better.”
If the air becomes uncomfortably dry in certain rooms, the painter suggested using a small bedside humidifier rather than allowing humidity to rise throughout the home.
They stressed that taking small daily steps helps, too: “Additionally, take the time to wipe up the condensation once in a while.”
While some homeowners turn to DIY plastic window film kits, the painter warned that they come with drawbacks. “You can plastic the windows but I’ve always found that tacky, no I mean literally.
« When you pull it off for summer the adhesive strip is usually left behind on the trim.”
As temperatures drop further in the coming weeks, moisture control is essential, and a dehumidifier remains the most effective tool for preventing winter condensation from turning into long-term damage.
