Egg crate grilles are lightweight aluminium ventilation grilles with a distinctive open lattice pattern that provides approximately 90% free area — the highest of any standard grille type. That makes them the go-to choice for extract and return air applications where you need to move high volumes of air with minimal noise and pressure drop. We stock them in 9 sizes for ceiling or wall mounting, all in a white powder-coated finish, with an optional opposed-blade damper for airflow balancing. Every size is in stock with next-day delivery available.
An egg crate grille is a ventilation terminal used primarily for extract and return air — it covers the opening where stale air is drawn out of a room and back into the ductwork. The open lattice design gives approximately 90% free area, meaning almost no resistance to airflow. That's significantly higher than a double deflection grille (typically 60–80% free area), so egg crate grilles are specified wherever you need to shift large air volumes without creating noise or excessive pressure drop. Common applications include office ceilings, server rooms, commercial kitchens, plant rooms and above suspended ceiling voids.
What sizes are available?
We stock egg crate grilles in 9 standard sizes. The stated sizes are the nominal duct or aperture size — the overall dimension including the mounting flange is slightly larger. The 550×550mm size is the standard tile replacement for 600×600mm suspended ceiling grids and drops in without screw fixings. Smaller sizes from 150×150mm up to 450×450mm are screw-fixed to ceilings, walls or bulkheads. If you need a non-standard size or rectangular format, get in touch — we can source made-to-order grilles.
Can I use an egg crate grille for supply air?
Technically yes, but they're not ideal for it. Egg crate grilles have no adjustable louvres, so you can't control the direction or throw of the air. For supply applications you'll get better comfort from a 4-way ceiling diffuser or a double deflection grille with adjustable blades that let you direct the airflow and avoid cold draughts at occupied level. Egg crate grilles work best for extract, return air and air transfer where direction control doesn't matter — you just need the air to get through with minimal resistance.
Do egg crate grilles come with a damper?
Our egg crate grilles are available with an optional opposed-blade damper. The damper sits behind the grille face and lets you restrict or open airflow for system balancing during commissioning. If you're installing multiple extract points across a building, dampers are essential to ensure each zone gets the correct air volume. Without a damper, the grille is fully open and flow is controlled only by the duct sizing and fan capacity upstream. Select the damper option when ordering if you need it — it's pre-fitted to the grille frame.
What is the difference between an egg crate grille and a return air grille?
An egg crate grille is a type of return air grille — the terms overlap. The difference is in the blade pattern. Egg crate grilles use a square lattice (intersecting horizontal and vertical blades) which gives the highest free area and lowest resistance. Standard return air grilles use parallel fixed blades, which offer a cleaner visual line but slightly less free area. For most commercial extract and return applications, egg crate grilles are the default specification because they combine high performance with low cost. If aesthetics matter more — for example in a reception area or retail space — a double deflection grille may look better, but it will have more pressure drop.
Can egg crate grilles be used as non-vision transfer grilles?
Yes, this is one of their common uses. Fitting an egg crate grille into an internal wall or door allows air to transfer between rooms while maintaining a degree of visual privacy — the lattice pattern breaks up the line of sight. This is useful in commercial buildings where ventilation air needs to pass from corridors into offices or from open areas into enclosed rooms. For fire-rated walls, always check whether a fire damper is required behind the grille — see our fire dampers collection or call us on 0161 818 2050 for advice on Part B compliance.
How to choose the correct size egg crate grille
The correct grille size should match the ceiling tile opening, duct neck, or return air aperture, while also allowing the required airflow to pass at low face velocity.
Larger grilles are typically preferred in high-volume systems to reduce pressure drop and maintain quieter airflow performance. When calculating grille size, consider both the duct connection and the room’s air change requirements to ensure the HVAC system meets design specifications.
Oversized or undersized grilles can lead to turbulence, noise, or inefficient system performance.
Do egg crate grilles affect noise levels in a ventilation system?
Yes. With a high free area and low airflow resistance, correctly sized egg crate grilles help minimise turbulence and noise in return or extract systems. Incorrect sizing can cause whistling or uneven airflow, so proper specification is key for quiet, efficient performance.
Are egg crate grilles easy to maintain?
Yes. Egg crate grilles are simple to remove and clean, giving easy access to ceiling voids or ductwork for inspections. Regular cleaning prevents dust buildup, maintaining airflow efficiency and reducing energy costs. In high-traffic commercial spaces, quick-maintenance designs help limit system downtime.
How do egg crate grilles impact HVAC system efficiency?
They support efficient airflow with minimal pressure drop, reducing fan energy use and maintaining balanced air movement across the system. Their open design helps keep return and extract performance consistent without compromising comfort levels.
Can egg crate grilles be used in high humidity or industrial environments?
Yes. Aluminium or powder-coated steel versions offer excellent corrosion resistance, making them suitable for damp, industrial, or coastal applications. Choosing the right material extends service life and sustains long-term system efficiency.
How do I integrate egg crate grilles with existing duct systems?
Egg crate grilles are installed over return openings or duct ends. Match grille size to duct dimensions and position carefully to avoid air turbulence. They can also be paired with diffusers or deflection grilles for enhanced airflow control in mixed systems.
