Trickle Vents for Windows [Preventing Condensation]

what are trickle vents

Over recent years, huge Improvements have been developed for draught proofing and anti condensation technology. Modern windows are designed to be airtight, to achieve greater energy efficiency and heat retention, this is fantastic for draught prevention, keeping homes toasty warm.

An entirely sealed property can cause moisture build up and reduce air quality. Maintaining a healthy and comfortable interior environment requires your home to be well ventilated. This is the reason window manufacturers (usually) fit trickle vents to window installations. Let’s take a look at some of the best air tight vents for windows, to help stave off unwanted condensation and damp build up.

Best Trickle Vents for WindowsBest Trickle Vents for WindowsMerriway

Trickle ventilators (or trickle vents) provide this effective background ventilation for a home, contributing to a healthy living environment by enabling unobtrusive and controllable in.... Read more.

Trickle Vents for Wooden WindowsTrickle Vents for Wooden WindowsMerriway

A property or building that does not have sufficient ventilation is a building waiting for condensation problems to occur. The most obvious sign of condensation problems due to no... Read more.

Trickle Vents for UPVC WindowsTrickle Vents for UPVC WindowsRW Simon Ltd

Our selection of trickle vents are an ideal solution to fit to your UPVC windows and/or patio doors. By installing trickle vents, this increased air circulation and improve air quality within... Read more.

Trickle Vents for Sash WindowsTrickle Vents for Sash WindowsTiton

A trickle vent can either be, always open, or closable with a flap. It allows air to constantly circulate around a building; preventing condensation and future damp problems without having a.... Read more.

Small Trickle Vent for Patio DoorsSmall Trickle Vent for Patio DoorsFrom the Anvil

Trickle vents for the replacement of existing, tired, missing or broken slot vents found on double glazed patio doors. They will help avoid problems associated with poor ventilation, such as... Read more.

Trickle Vents for Aluminum WindowsTrickle Vents for Aluminum WindowsBROOK

A window trickle vent is often used in double glazing to increase ventilation. ... of framing materials such as UPVC, timber, steel and aluminium. They allow a small amount... Read more.

Trickle Vents That Meet Building RegulationsTrickle Vents That Meet Building RegulationsFV

Trickle Vents are a requirement under building regulations. The Building Regulations Requirement F1 – Means of ventilation require that 'there shall be adequate means for ventilation... Read more.

Trickle Vent to Help Prevent CondensationTrickle Vent to Help Prevent CondensationSimon

Trickle vents are fitted to the tops of window frames and can help create ventilation and reduce condensation. The small opening allows small amounts of ventilation in to help reduce... Read more.

Trickle Vent for Large Double Glazed WindowsTrickle Vent for Large Double Glazed WindowsBROOKVENT

Trickle vents in double and triple glazed windows, why do we have them? Modern houses have become better insulated, so trickle vents may be a great way to preserve air circulation in... Read More.

Easy Fitting Trickle Vent KitEasy Fitting Trickle Vent KitSavorsUK

Fitting trickle vents to your windows and doors can help to prevent condensation that contributes to mould growth that could be harmful to you and your families health. The best... Read more.

air vents for glass windows

What are trickle vents

Installing or fitting trickle vents in your doors and windows is an easy and safe way of dealing with condensation problems. The hot air gathers inside your home and gravitates towards the cooler surfaces. These are often windows and doors. The windows and doors are usually in a recesses so the warm air is trapped. It rises to the head of the window or door where (if there is an open trickle vent) it can escape.

Do trickle vents help stop condensation?

Although double or triple glazing hugely reduces condensation by insulating rooms from the cold outside, it can occasionally be part of the problem. That’s why the the most effective way to combat condensation is to ventilate any affected rooms by partially opening the window or opening up the trickle vents in the top of your window frame, if you have them. (It may feel like you’re letting all the heat escape but actually, you’re replacing warm, moist air with cool, dry air that’s cheaper to heat in the long run.)

If that doesn’t get rid of the problem, there are other steps you can take, depending on what kind of condensation you have and what’s causing it. Use our easy checklist to assess the nature of your condensation problem and the best way to tackle it.

What are trickle vent building regulations?

The Building Regulations in England and Wales require ‘that there shall be adequate means for ventilation provided for people in the building. It however now differentiates between windows for residential installation in either a Replacement or New build application.

If the window being removed has trickle vents fitted, then the replacement window should also have them – to the same level of performance.

The ventilators fitted to the replacement window should therefore offer at least the same capacity as the ventilators fitted to the removed window.

Best alternative to trickle vents?

There’s a very simple alternative to Trickle Vents – opening a window. It’s a good idea to open all the windows in the house for a few minutes every day (yes – even in winter!) to allow moist air to escape, and dry air to replace it. This is especially important in the bathroom and kitchen.

You could also consider air bricks, but require professional fitting.

There are different types of air brick. The traditional type is the clay air brick, heritage air bricks tended to be cast iron – which are sometimes very ornate – and the modern air bricks are plastic. In our opinion, the clay air brick is more in keeping with the look of most properties and consequently is the one we tend to use, although this is a little more expensive than the plastic type.

They are situated in the outside wall, above ground level, but at a height so they are underneath the internal timber floor. They should never be partially submerged in the ground.

The holes in the brick allow air to flow through into the underside of your floor reducing the humidity, clearing the stagnant air and keeping the area cool.

how to open trickle vents

How to fit trickle vents

Adding a trickle vent is as simple as drilling a new ventilation hole through the frame. You will need a drill bit that’s designed for uPVC, as you will be drilling through layers of plastic and metal at the same time.

Measure and mark where the vent will go, and do the same for the opening you need to create. Drill the new vent hole from outside inwards, then repeat the drilling from the inside out, keeping the drill absolutely straight for a perfect vent opening.

Once the horizontal vent holes have been drilled, you will need to fix the actual trickle vent over the top. The vent may have a grille to prevent flies and insects from getting through; make sure the grille is always on the outside. Simply screw the vent in place over the hole you created.

It’s very difficult to fix a window frame if a DIY job goes wrong, so proceed with caution and take your time. In particular, take care to get the vent absolutely central. If it’s off to one side, it’ll look strange and could ruin the whole appearance of your home.

Trickle vent installation cost?

It’s a simple enough job to retro fit trickle vents to window heads,
window manufacturers will stock them in colour to suit. Basically drilling holes in head of frame couple of screws to fix is all that’s needed, but if you require a handy man to do the job it wouldn’t cost much as long as you’ve already purchased a trickle vent from a shop like amazon, wickes, screwfix or eBay.

How to open trickle vents?

This fantastic video explains how to install a trickle vent and also shows you how to open and close them.


Although we want to keep our homes warm and avoid draughts, we actually need a certain level of ventilation. In order to provide a healthy and comfortable internal environment. So before when we had draughty old windows that would let in a breeze, we didn’t need to have trickle vents. Now that we have new windows with better seals against the elements, we need to find a way to allow a change of air within our homes and trickle vents are perfect for the job.

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