Is it OK to close trickle vents?

Author: Magnus Marquardt  |  Last update: Tuesday, March 11, 2025

Trickle vents allow a small amount of air through the window at all times, and can be opened or closed manually, however, it is recommended that trickle vents remain open at all times to keep fresh, clean air flowing through the home.

Should you ever close trickle vents?

Trickle vents should be open all the time to provide passive ventilation. However like opening windows on a wet or foggy day you likely to experience import of moisture rather then export.

Should trickle vents be sealed?

The trickle vent is essentially a slit in the frame, staggered on the inside and outside, with a cover that can be opened and closed. Although the vent can be closed, they are designed to be left open all the time for continual ventilation.

Can I block up trickle vents?

They are your Trickle Vents and it's your home, so there is little stopping you from removing the inside cover, filling the holes with silicon, or any filler and replacing the cover. However, 5 Star do not advise blocking Trickle Vents, as simply closing them, takes any airflow to near zero.

Should trickle vents be open or closed in summer?

Use your trickle vents

By leaving your trickle vents open during the summer, air can travel freely throughout the home without letting in the hot and humid air as well as keeping out those pesky flying insects.

What are Trickle Vents? Do you need them?

Do trickle vents cause heat loss?

One question we are receiving a lot as a result of this update is whether trickle vents can cause heat loss in the home. The short answer is no*, but allow us to explain why you don't need to be concerned about heat loss through trickle vents.

Which vents should be closed in the summer?

(Hint: In the summer months, open the top vents and close the bottom ones to draw out air from a higher point in the room where it's hotter).

Can I refuse trickle vents?

New rules (after 15 June, 2022)

In line with the new rules, all windows and doors must be fitted with trickle vents, unless there is an alternative, dedicated ventilation system fitted.

What are the disadvantages of trickle vents?

The Disadvantages of Trickle Vents:

Trickle vents, particularly when open, can increase noise pollution in the home by creating an opening in the sealed window. Maintenance: All windows require regular maintenance throughout the year, particularly during Spring cleaning.

What is the advice for trickle vents?

When should I open trickle vents? Trickle vents should usually be left in the open position. If you're planning to use any background ventilators with an automatic system, they should also have a manual override.

Can I cover trickle vents?

Trickle Vent Canopy

The exterior side of a upvc window vent is just a simple canopy or cover that is there to finish the slot and provide resistance to ingress of water and insects (to some extent anyway).

Do trickle vents let water in?

Do trickle vents let water in? Trickle vents are designed to allow a small, controlled airflow, but they are specifically designed to prevent the entry of water. The opening of the trickle vent is small enough to prevent the ingress of rainwater, while still allowing air to flow in and out of the room.

What is the best alternative to trickle vents?

Passive Wall Ventilation

They do not need a power supply, so can be located anywhere in the room, generally at high level. Passive wall vents are generally far superior to using window trickle vents.

Is it better to keep vents open or closed?

We recommend keeping vents and interior doors open as much as possible for the best airflow. If comfort is an issue, try closing certain vents partially.

Can bugs get through trickle vents?

No. Trickle vents have insect screens that prevent bugs and dirt from getting through. Should trickle vents be installed in commercial buildings? Background ventilation like trickle vents are required in commercial spaces.

Should I close trickle vents at night?

Night-vent or night-latch positions – where the window is held slightly ajar by the handle – are a security risk. Windows should be fully closed when a house is unoccupied. Trickle vents are a secure form of ventilation and can be left open even when you are on holiday.

Do trickle vents make a room colder?

Without trickle vents, rooms would be liked a sealed box, with no natural ventilation coming through. The potential for trickle vents to cause heat loss is a common concern, but the amount of heat that trickle vents actually allow to pass through is very minimal, and doesn't enable a lot of heat to escape.

Will trickle vents stop mold?

Trickle vents are designed to allow a small amount of 'background' air circulation. This will assist in reducing condensation, damp and mould inside properties especially around windows as these are normally the coldest place in a room so therefore the first place that condensation will form.

Are closing vents bad?

Closing air supply vents increases the air pressure inside the air ducts, which backs up into the ductwork of the home and can cause leaks. It also forces a greater volume of heated air out through duct leaks into unconditioned zones of the house.

Do trickle vents contribute to heat loss?

They provide effective ventilation in the same sense that an open window would. Additionally, they provide increased ventilation in a secure way that does not require an open window. Therefore, it does not cause as much heat loss as an open window would, for example.

Do all windows now need trickle vents?

It is mandatory for windows and doors to have trickle vents, whether going into new openings or when replacing your old windows. The information around trickle vents is confusing; even some door and window installers may provide the wrong information.

Should you close vents in unused rooms in Summer?

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.

Can you have too much return air?

Can You Have Too Much Return Air? Too much return air coming through your system isn't much of an issue because the fans and ductwork working to get that air back into the system only pull with so much force to make the HVAC system work correctly.

Is it bad to cover a vent with furniture?

Avoid blocking air vents with pillows, furniture, plants, or pictures. When the air vents are blocked it means that heated or cooled air needs to squeeze by what is blocking it to reach the rest of the room.

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