Trickle Vents and Window Ventilation: Do You Need Them?
4 September 2025 · 4 min read
Those little slot vents on windows aren't just an afterthought — they tackle condensation and damp. Here's the deal.
What trickle vents do
Trickle vents are small, controllable slots — usually in the top of a window frame — that allow a little background air in even when the window is closed. That gentle airflow carries away moisture, reducing condensation, mould and stuffiness, especially in well-sealed modern homes.
They can be opened or closed to suit the weather and the room.
Are they required?
Building Regulations increasingly call for adequate background ventilation when windows are replaced, so new windows often include trickle vents. They are particularly valuable in bedrooms, kitchens and bathrooms where moisture builds up.
Modern airtight homes need this ventilation more than draughty old ones did.
Adding ventilation
If you suffer from condensation, improving ventilation — including trickle vents — is often part of the solution alongside fixing any failed glazing. We can advise on whether your replacement windows should include vents and fit them as part of the work.
Ask us about ventilation when you get a quote for new windows or units.
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