Improving Air Quality and Comfort with Joinery-Integrated Trickle Vents

Sashvent - Altherm Window Systems

As buildings become better sealed and more energy efficient, the challenge of getting fresh air indoors, without compromising thermal performance or security, has become more pressing. The best time to address this issue is at the design stage.

Today, we’re focusing on one effective and often underappreciated solution: integrating joinery with built-in vents (commonly known as trickle vents or T-vents) as a passive way to bring in fresh air, without having to open a window or rely on someone remembering to do so. These small, often overlooked features can play a big role in improving air quality, comfort, and wellbeing, especially during colder months when opening windows simply isn’t practical.

The Problem with Sealing Buildings Too Well

Modern homes and schools are increasingly airtight, which is great for thermal performance, but it can also trap stale air, excess moisture, and CO₂ inside. Without proper ventilation, this leads to condensation, discomfort, and in the long term, mould and respiratory issues.
In winter, the problem intensifies. Windows are kept closed to retain heat, but this also means no fresh air is entering the building. In schools, this often results in classrooms with poor air quality that can impact student focus and learning. In homes, it’s a common cause of damp rooms and poor sleep quality.

How Joinery Vents Work

Joinery-integrated vents are built discreetly into the frames of windows or doors. They allow a small but steady stream of fresh air to flow into the building — without any manual input required and without compromising security or thermal performance.

Benefits include:

• Passive, consistent airflow throughout the day and night
• Reduced condensation and humidity, particularly in colder seasons
• Improved indoor air quality, supporting health, comfort, and cognitive performance
• Maintained insulation and energy efficiency, unlike open windows
• Enhanced security and noise control, as windows can stay shut

Depending on the system, vents may be manually adjustable or operate automatically using pressure or humidity-sensitive mechanisms — all with minimal visual impact.

How We Integrate Them

At Nala Studio, we plan for passive ventilation early in the design process. We work with consultants to identify where joinery vents can be most effective — in bedrooms, bathrooms, living spaces, or high-occupancy environments like classrooms.

This is particularly important in schools, where we’re seeing increased awareness of indoor air quality thanks to research initiatives like Massey University’s Healthy Schools project. These studies show how quickly air quality can deteriorate in closed classrooms, and how even simple ventilation strategies, like passive vents, can make a measurable difference in student health and learning outcomes.

In homes, joinery vents offer a low-maintenance way to maintain healthy airflow year-round — particularly valuable in compact or well-insulated dwellings where natural cross-ventilation is limited.

Small Detail, Big Impact

Trickle vents may not draw attention, but they address a growing need: keeping indoor spaces healthy and liveable, even as buildings become more airtight and efficient. They’re a passive, energy-free way to support ventilation, often more efficient and sustainable than relying solely on mechanical ventilation systems which require electricity to operate.

As one of many passive strategies we use, trickle vents help design environments that are comfortable, resilient, and user-friendly, year-round.

At Nala Studio, it’s just one more way we ensure the buildings we design don’t just meet performance standards — they improve daily life.

Bonus Tips: Getting the Most Out of Joinery Vents

If you're considering T-vents in your next project, here are a few design and product considerations to maximise their effectiveness and occupant comfort:

• Focus on naturally automated trickle ventilators - These systems respond passively to changes in indoor air pressure, temperature, or humidity — opening and closing without any electrical components or user input. They offer a low-maintenance, energy-free way to ensure consistent ventilation.
• Avoid horizontal draughts - Select vents with angled internal profiles that direct air upward or diagonally. This prevents cold horizontal airflow that can feel like a draught, particularly in living or learning spaces.
• Support air movement with door undercuts - In both homes and schools, consider including a small undercut at the base of internal doors. This encourages cross-room airflow, helping fresh air circulate more effectively and reducing stagnation in closed rooms.

Author
Deni Star (Nala Studio Architects)