Why do new windows have vents?

Author: Dr. Edwardo Heidenreich DDS  |  Last update: Tuesday, January 27, 2026

Permitting a small amount of air to flow from one side of the window to the other, trickle vents allow you to benefit from fresh air without opening your windows or doors, reducing the harbouring of germs and bacteria throughout the property.

Do new windows have to have vents?

In most cases, trickle vents are required to be fitted in new windows. Where should trickle vents be fitted? Trickle vents should be fitted at a minimum of 1.7m from the floor to avoid draughts. Vents are integrated into the head of the window frame.

What are the little vents on windows for?

Window trickle vents are small vents that are installed in the frame of a double glazed window. They allow air to flow in and out of the window, which helps to regulate the temperature and humidity inside your home and importantly reduce condensation.

What is the point of window vents?

Your window vents flush your home with fresh outdoor air to improve your indoor air quality. They do so in a highly energy-efficient way, as this natural supply of air does not use any electrically powered elements.

Why do they put vents under windows?

Efficiency and Air Flow

Further, adding the vents here prevents your home from having a convection current that draws cold air in. It instead buffers the cold air from outside and prevents cross drafts which could make you less comfortable in your home during the winter.

What are Trickle Vents? Do you need them?

Should I close the vents on my windows?

Our advice is to leave them fully open at all times. What happens if I don't use my tickle vents? These vents help prevent or minimise problems associated with poor ventilation, such as condensation and reduce the risk of mould growing in unwanted places and dampness in the house.

Should I open the vents under my house?

However, after much research and analysis, the consensus nowadays is that crawl space vents should be closed. While it may seem reasonable to keep them open for ventilation, it's quite the opposite. Open vents can lead to various issues, including moisture buildup and insect infestations.

Do window vents need to be open?

Home > Is your Trickle Vent open? As properties grow evermore air tight in the quest for energy efficiency, it is essential to maintain a comfortable and healthy indoor environment by opening your window trickle vents.

Are window vents any good?

By installing vents into your windows, you can remove stale air and unwanted smells, resulting in a fresh and well-ventilated home. Condensation, carbon monoxide, and carbon dioxide are background air pollutants that can cause health problems, mould growth, and damage to internal surfaces.

Why do double glazed windows have vents?

Trickle Vents are particularly useful in air tight double glazed replacement windows and doors, enabling fresh air to flow continuously even when the windows are closed. This feature ensures a consistent airflow without significantly compromising security, energy efficiency, or the overall aesthetic of your windows.

Do window vents make a room cold?

If your windows are well insulated with double glazing or triple glazing, they will be able to retain enough heat to keep the house warm, even with trickle vents still open. If your house is losing heat from its windows, it's recommended to replace your glazing and invest in good draught-proofing.

Why did they get rid of vent windows?

A: There are probably several reasons why the vent window was eliminated. Cost may have been one. Reduced aerodynamics may have been another. And they outgrew their usefulness when air conditioning became nearly universal.

How do you block air vents in windows?

Take the vent covers off and apply clear gorilla tape over the holes. I would suggest masking off the outside area of the covers prior to taping as that the tape sticks. You can then trim back after refitting covers. That should resolve your issue.

Should all new windows have trickle vents?

From 15th June 2022, any newly installed windows and doors must be fitted with trickle vents. This is to do with Part F of the Building Regulations. Meeting Part F of the Building Regulations is not new – it's actually been a requirement since 2010 and had the last update on the 15th June 2022.

Would you like to buy a house having windows but no ventilation?

No, a house which has no ventilators is not a safe or healthy house to live in. The air circulation is not there is such a house. So, it has no fresh air. Because warm air rises up and goes out through ventilators and fresh air comes in through windows.

Do new windows keep cold air out?

Energy-efficient windows are designed to prevent heat transfer between the inside and outside of your home. They act as a barrier to keep the cold air out during the winter and hot air out during the summer. Double-pane windows with low-E glass is one of the best choices available.

Are windows supposed to have vents?

If a window is not well ventilated then it can lead to condensation build up which, if left, can lead to the proliferation of potentially harmful mold spores.

What are window vents used for?

These vents are designed to help prevent or minimise problems associated with poor ventilation, such as condensation and mould growth. Additionally, they help remove stale air from the property, which is very helpful if there are any odours lingering in your home.

Can spiders get in through trickle vents?

Spiders don't wait for you to come home from work or the school pick-up and then stroll through the front door, hoping you won't see them. They're a little more ambitious. They'll come through open windows, trickle vents (the narrow plastic openings above windows used to control air flow) and exterior air bricks.

Should I close the vents on my windows in winter?

Trickle vents prevent mould and condensation build up by allowing a controlled amount of air to escape the window, so we do recommend keeping them open throughout winter. The calling of the internal temperature in winter from a trickle vent is quite marginal.

What is the alternative to trickle vents in windows?

Mechanical ventilation with heat recovery (MVHR) is a suitable alternative to getting trickle vents. It uses heat from outgoing air to warm up any incoming fresh air without compromising the quality.

Why are vents always under windows?

Additionally, having a vent under a window helps promote air circulation in the room by creating convection currents that move hot or cold air around more efficiently.

Is it OK to cover air vents in house?

It will certainly continue to release air to those vents, and also if they're closed, you might cause a buildup of atmospheric pressure and not enough air movement which can damage your system.

Why should you not close vents in unused rooms?

Lost Efficiency

Closing the vents doesn't do it any favors. In fact, instead of helping the air conditioner cool less, closed registers force the same amount of air through other ducts. This builds pressure in the system and makes your HVAC system work harder to distribute the air where you need it.

Why do old houses have air vents?

It's important to remember that static vents serve a purpose, especially in older homes. They provide ventilation to indoor spaces, help regulate indoor temperatures and prevent the build-up of excess moisture in wall cavities and rooms which can lead to mould outbreaks and damage to building materials.

Previous article
Can I use dish soap to wash walls before painting?
Next article
What's the best anchor for brick?