What are Trickle Vents?
What are Trickle Vents?

Ventilation plays a huge role in keeping a home healthy and comfortable, but it’s something many people only think about when problems like condensation or stuffy rooms appear. One small, often overlooked feature that can make a big difference is the trickle vent.
So, what exactly are trickle vents?
Trickle vents are small openings built into the frames of windows that allow a controlled amount of fresh air to circulate indoors, even when the window is closed.
They’re usually found at the top of modern windows and can be opened or closed manually with a simple slider.
Why do homes need trickle vents?
Moisture, indoor pollutants, and stale air build up in every home through everyday activities such as cooking, showering, drying clothes, or simply breathing. If this moisture has nowhere to escape, it can lead to condensation, damp patches and peeling paint, black mould, poor air quality and musty smells.
Trickle vents provide continuous background ventilation, helping prevent these issues by allowing moisture-laden air to escape and fresh air to enter.
Are trickle vents a requirement?
In the UK, building regulations now (since 2022) require the use of trickle vents in most replacement and new-build windows to maintain healthy airflow. They help ensure a minimum level of ventilation without relying on windows being open all day long.
Do trickle vents make your home colder?
This is a common concern, but they don’t have a significant impact on the temperature of your home.
Trickle vents allow only a small, controlled flow of air. They don’t create large drafts, and they shouldn’t noticeably reduce the warmth of your home. In fact, by reducing dampness and improving air quality, they often make a home feel more comfortable.
Should you keep trickle vents open?
For the best results, yes, especially in winter when condensation is most likely. You can close them if needed (for example, during high winds), but keeping them open ensures a steady flow of fresh air and keeps humidity under control.
Trickle vents may be small, but they play a big role in maintaining a healthy indoor environment. They’re a simple, cost-effective way to reduce condensation, prevent mould, and improve overall air quality — all without opening your windows or compromising security.










