Why not having trickle vents could be more serious than you think

Although you may know the answer to what are trickle vents, you may still wonder if that little flow of air really makes a difference to your home ventilation. Or, perhaps you feel it's a bit of an inconvenient eyesore that lets your heating flows out and an annoying draught come in.

But the reality is we do need them – albeit not in all homes – and in some cases there are potentially serious consequences if you don't have them.

So just what powers do these little strips of slatted plastic have, why doesn't every home in the UK need them and what happens if you should have them but you don't?

What are trickle vents?

In terms of their practical appearance, trickle vents are usually found at the top of your window or door frame.

“They are small openings built into window or door frames that allow a continuous flow of fresh air into a building, even when the windows are securely closed," explains Anthony Threlfall, head of marketing at Everest.

That said, while the most common version is found in the frame and has a plastic cover that can be opened or closed, there are in fact three types of trickle vents says Anthony:

• Through-frame or through-sash vents: The most common type, integrated directly into the window frame or sash
• Over-frame vents: Fitted above the window frame, often used when through-frame vents aren't possible
• Glazed-in vents: Positioned in the glazed area of the window, though this type may detract from aesthetics and is less commonly chosen

Why do we need trickle vents?

Anyone who's ever found a mould hotspot in their home, or become frustrated with a sweating toilet will understand the importance of home ventilation.

"Home ventilation is the exchange of air between what is inside the property and the fresh air outside. Inside, the air is typically warm, moist and often stale as we generate a lot of moisture as part of our daily routine through bathing, cooking, drying clothes, and even breathing. This, combined with cooking fumes, cleaning products and other indoor pollutants, creates the stale air in our homes," explains Gregory Smith, property expert at PriceYourJob.

"As a result of the warm, moist air, the humidity levels inside the property will rise. When this moisture meets a cold surface, it will form condensation and small water droplets, which, if not removed, can cause mould and mildew to grow on the surface.

"It’s important to ensure there is a regular exchange of air to prevent this buildup of condensation and its associated problems, which is where home ventilation comes in. Without it, there is nowhere for the stale, warm air to go, and it will remain trapped in your home," warns Gregory. "Even though we are focused on energy conservation and reducing our heating bills, fresh air is fundamentally important not only to your health but to the condition of your property."

And while measures such as house burping can allow bursts of fresh air in, they are reliant on you remembering to do so, which is where the benefits of trickle vents start to reveal themself.

“Trickle vents help improve ventilation by allowing a “trickle” of air to circulate, preventing indoor air from becoming stagnant while reducing moisture build-up from the air that can cause mould," says Anthony Threlfall.

And while it's common to associate damp and mould with older properties, "they are just as important in modern houses which are designed to be more airtight,” confirms Anthony.

Gregory Smith

Gregory Smith has worked in the property and construction industry for over 20 years. He currently continues to work on domestic building projects while also providing expert comments in the property and construction field for PriceYourJob.

Trickle vents and building regulations

Of course, as well as their ability to improve air flow around the home, there's also bigger problem if you don't have trickle vents. They are part of the building regulations standards covering ventilation, meaning if you don't have them in your home, you could be breaking the rules.

“As of 15 June 2022, Building Regulations in England and Wales mandate that trickle ventilation must be fitted on all replacement windows and doors in habitable rooms," warns Anthony Threlfall.

"This includes bedrooms, living rooms, kitchens, and bathrooms - but excludes hallways and stairwells. Scotland already had similar requirements in place prior to this."

So, while trickle vents may only be providing background ventilation, it's considered an integral part of the rules when building a house. Although, as we'll cover next, not all homes are required to have them.

Do all homes need them?

Despite their obvious value, there are some situations when trickle vents may not be needed, and those where they should be installed – but they aren't.

“Certain scenarios may make trickle vents unnecessary or undesirable. Homes with mechanical heat recovery systems or continuous extract ventilation systems, for instance, typically do not require them to meet Building Regulations.

“On top of this, listed or historic buildings may be exempt from having trickle vents to preserve the property’s aesthetic. However, other forms of background ventilation would need to be provided to meet regulations," explains Anthony Threlfall.

Other scenarios when you may not spot trickle vents in place include:

• Older window installations: Windows and doors fitted before the 2022 regulation change may not include them
• Installer oversight or miscommunication: Some installers may not inform customers about the requirement - but, this is a legal requirement and can impact the sale of your property if you do not comply

Pros and cons of having trickle vents

When it comes to the pros and cons of having trickle vents, it's important not to underestimate just how powerful these little strips are. While they may only be a small cog in the big wheel of home ventilation, the consequences of poor air flow are big.

Issues with damp and mould may only seem like surface problems, but in fact run deeper, says Gregory Smith.

"Mould spores are bad for babies and young children, the elderly, people with respiratory problems, or those suffering from chronic conditions. More than anything else, safeguarding the health of your family or other occupants of the property should be a priority," he explains..

Add to this the fact damp caused by condensation due to poor ventilation, can cause structural issues in the house if left untreated and it becomes clear to see why the small steps can make a difference.

"Roof timbers can rot as a result of persistent dampness in the loft and may weaken the supports of your roof," warns Gregory. "Other areas, such as the kitchen and bathroom, can also suffer damage to wooden structures when there is a lack of ventilation."

And, one positive to trickle vents you may not have considered is how they can help with your home security costs, says Anthony Threlfall.

"Trickle vents allow for ventilation without compromising the security of your home. Some windows do have night latches, but these are not secure – they are an open window and would potentially not be accepted by insurance companies if you left your windows on the latch and were broken into."

Are there any downsides to having trickle vents?

That said, there are always two sides to every story and some of the potential downsides of trickle vents, according to Anthony Threlfall, could be considered as:

• Noise intrusion: It's worth noting that adding trickle vents to windows can impact any noise reduction measures you have on your windows. Since they create small openings, external noise can enter more easily
• Potential draughts: If left open during cold weather, trickle vents can create draughts in the room, but as mentioned, you can close them during the colder months
• Cleaning: The vents can accumulate dirt, so it’s important to keep them clean

Using trickle vents

“Although the vent itself can also be closed, they are designed to be left open all the time for continual ventilation, ensuring a gentle, uninterrupted flow of fresh air," advises Anthony Threlfall.

"This discreet, yet effective, ventilation helps expel moisture and airborne pollutants, preserving the purity and comfort of your home," he says, all while you carry on with your life.

"However, for optimal use, consider combining trickle vents with other forms of ventilation, such as the best extractor fans for bathrooms, and making sure your kitchen ventilation system is fully comprehensive," he advises.

FAQs

Should trickle vents be closed in winter?

“While trickle vents can technically be closed, it’s advisable to keep trickle vents open in winter to prevent damp and condensation," says Anthony Threlfall. "If you do close them due to cold draughts, ensure regular ventilation by opening windows for short intervals to maintain healthy air circulation.”

Do they affect the type of window covering you can have?

“Generally, trickle vents shouldn’t interfere with most window coverings like blinds or curtains. However, bulky or close-fitting fittings may partially obstruct the airflow and reduce their effectiveness," warns Anthony Threlfall.

"For instance, as they are typically located at the top of the window frame, coverings that sit flush against, or over this area, like certain roman blinds, perfect fit blinds, or full-height shutters, might restrict airflow if not positioned carefully.”

Do trickle vent stop condensation completely?

“Trickle vents help reduce the likelihood of condensation by allowing moist air to escape and fresh air to circulate. However, in homes with excessive moisture production (for example from cooking, showers, or drying clothes indoors), additional ventilation measures may be required to fully prevent condensation," advises Anthony Threlfall.

Are there any alternatives to trickle vents?

Alternatives to trickle vents include mechanical ventilation with heat recovery systems for continuous airflow while saving energy, continuous extraction systems, particularly in kitchens and bathrooms, and ventilation fans for more targeted airflow.

"However, while these systems provide effective ventilation, they are typically more expensive and require additional installation considerations compared to trickle vents,” says Anthony Threlfall.

You may also want to consider roof vent tiles, suggests Gregory Smith, particularly if you are undertaking a loft conversion.

"In a property with an undeveloped loft space, the area acts as a vent for the rest of the house. However, once the loft is converted into living space, the added insulation, plasterboard, flooring, and wall coverings reduce the amount of air that can pass through, to and from the outside," he explains.

"This can lead to a buildup of moisture in the new conversion, particularly if an ensuite loft conversion bathroom has been added. However, even without this addition, there can be issues. Fitting roof vent tiles as well as trickle vents will provide a means for air to circulate in the loft and reduce moisture buildup."

Can you retrofit trickle vents?

“Yes, trickle vents can be retrofitted into existing window frames," says Anthony Threlfall, "but the process can be complex. It involves drilling holes into the frame, which requires precision to avoid damaging the structure.

"At Everest, we recommend installing new windows with integrated trickle vents for optimal performance and a seamless finish," he says.

Gregory Smith's final advice? Not to underestimate the importance of getting the ambient temperature in your home right, something that trickle vents can play a part in, by letting fresh air in – but in limited amounts.

"If warm air meets a warm surface, condensation doesn't happen," says Gregory, "therefore, maintaining a good level of heating in your home is important. The key is to get the right balance between having a warm, but well-ventilated environment inside the home so that there are fewer cold surfaces for moist air to condense on."

Keen to explore more ways of ventilating your home? Make sure you have the right natural ventilation in place, or discover find out the answer to 'can you retrofit MVHR into an existing home?'