A Guide to Trickle Vents

Trickle Vents

Trickle vents, head vents, night vents… slot vents… call them what you will, they are often the Marmite of the double glazing world. People either love them or hate them. Whatever your feelings they serve a purpose though. At Starglaze, we’ve put together a brief guide to save you losing your head over them.

What is A Trickle Vent?

In basic terms, when a window is manufactured, a slot is drilled into the plastic frame, and a cover is placed over it. The cover has a control on it which allows you to open and close the slot at will to let air gradually trickle into your home without the need to open your window entirely.

Types of Trickle Vents

• Through Frame Design: This is where the trickle vents are often positioned through the head of the frame.

• Over-Frame Design: When the trickle vent cannot fit through the frame, ventilation is routed over the frame or head of the window.

• Glazed In: The trickle vent is fitted into the glazed area along the top of the sealed glass unit.

• Framing Materials: Trickle vents can be fitted in all types of framing materials, such as UPVC, timber, steel and aluminium.

The Mechanics of Airflow and Control

While the concept of a “hole in the window” might sound counterintuitive to energy efficiency, trickle vents are engineered to be highly controllable. Most modern vents feature a manual “hit-and-miss” slider or a tilt-action flap on the internal side, allowing you to regulate the airflow depending on the weather. On particularly windy days or during extreme cold snaps, you can close the vent entirely to prevent whistling or heat loss. However, for the majority of the year, leaving them in the ‘open’ position allows for a constant “path of least resistance” for moist, stale air to exit the home. This creates a natural pressure balance that prevents the “stagnant air” feeling often associated with modern, highly-insulated properties.

Professional Installation vs. Retrofitting

When it comes to installation, there is a significant difference between factory-fitted vents and retrofitted ones. When you order new windows, the trickle vent slots are precision-routed using CNC machinery during the manufacturing process, ensuring the structural integrity of the frame remains intact. For those looking at trickle vent installation for existing windows, the process involves carefully drilling a series of holes or a continuous slot through the window sash or frame, which is then capped with an internal regulator and an external “hood” (to prevent rain and insects from entering). While retrofitting is a viable solution for homes suffering from severe condensation, it requires high precision to avoid damaging the internal steel reinforcements or the glass units within the frame.

Window Replacement For Effective Ventilation

If you are replacing your windows and your old windows have trickle vents installed, you will have to have replacement windows with trickle vents to comply with Building Regulations. Trickle vents help combat damp and moisture problems in your property, ensuring your home is extremely well ventilated.

Why Do We Need Trickle Vents?

In recent years, the drive has been more focused on increasing the energy efficiency of our homes. But while we have been busy making sure our homes don’t leak too much energy, we have also made them more airtight, which can have a bad effect on the air quality inside your home and contribute to problems with condensation.

Although we want to keep our homes warm and avoid draughts, we actually need a certain level of ventilation 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.

There are three main kinds of ventilation that can be suited to your home’s needs and your personal preference:

• Purge: When we want to circulate the air within our home rapidly, this is when we open a window.

• Extraction: If you have a room where occasionally it is exposed to air pollutants, and you want to control it when it is ventilated. For example, when you turn on your extractor fan in a kitchen or bathroom.

• Background: This is a small ventilation opening that allows the air to circulate slowly, and it is your trickle vent.

The main purpose of ventilation is to remove polluted air from your home and replace it with fresh air from the outside. Ventilation of your home is necessary to provide a healthy and comfortable environment.

Trickle Vents & Window Security

An open window can leave your home vulnerable to a break in, providing an easy point of entry. Window trickle vents provide a consistent supply of ventilation without compromising your home security. You can benefit from fresh air while leaving your window locked in a closed position.

Reduce Condensation With Trickle Vents

If your windows do not have trickle vents and you are replacing them then you don’t have to have trickle vents installed. However, you might like to consider them if you:

• Find your home stuffy and feel that it lacks fresh air.
• Have problems with condensation.
• Or would like to increase ventilation within, for example, a bathroom or kitchen. Cooking and showering are the primary cause of increased humidity levels within a home, therefore a carefully placed trickle vent can make a significant difference to a comfortable and well ventilated home.

All new houses and extensions must now have trickle vents fitted as standard to comply with building regulations. So, if you are buying new windows for this purpose, you will need to bear this in mind.

uPVC Trickle Vents

Lastly, it is sometimes possible to retrospectively fit trickle vents to existing plastic windows. So, if you are experiencing a problem with condensation and do not have a form of background ventilation, you could consider fitting trickle vents to your existing uPVC windows. It can be a time-consuming and tricky job, but it might be worth it if it could alleviate your problems.

Get In Touch For Window or Trickle Vent Installation

Starglaze offers a full window installation service, including the fitting of trickle vents with our double-glazed windows. For more information, please use our online enquiry form or call us on 01522 512020.