Ventilation Grille Exterior Gravity Louvre 485x485mm PVC Grey, Vents-Group

Quick Facts — Vents-Group Ventilation Grille GRM-485

• Outer dimensions 484 x 484 mm, mounting holes 420 x 420 mm
• Automatic gravity louvres in grey PVC
• Single, undivided louvre construction
• Grille frame in powder-coated metal, grey colour
• One-way airflow — prevents backdraft
• Weather- and impact-resistant, colour does not fade
• For mounting on vertical surfaces (walls) only

The GRM-485 ventilation grille terminates the extract duct and protects against weather and draughts by closing automatically when the fan is off. The grey PVC louvres are lifted open by the airflow during forced extraction and fall back to the closed position as soon as the fan stops.

In strong wind or with a large pressure difference between indoors and outdoors, the louvres may produce some noise when opening and closing — this is normal and does not affect function.

Key benefits of the GRM-485

The grille frame is made of metal coated with a weather-resistant and mechanically durable polymer coating, giving high resistance to weathering over time without the colour fading. The construction is single and undivided at this size, with the grille fixed via two mounting points at the rear for quick and stable installation. The lightweight PVC louvres open automatically under airflow, ensuring flow in one direction only with no moving parts requiring adjustment.

How do the automatic louvres work in operation?

When the fan is running, the louvres are opened by the airflow and let the air out freely. When the fan is switched off, the louvres fall back and close the duct, preventing cold outdoor air or draughts from entering the room through the extract duct. This function makes the grille suitable as a termination in ventilation, air conditioning and heat recovery systems.

Where is the ventilation grille best installed?

The GRM-485 is installed outdoors on vertical surfaces, i.e. walls, as the termination of an extract duct. The size suits homes, smaller commercial premises and standard ventilation systems well, while the grille also protects against debris and precipitation entering the building.

Model and dimension overview, GRM series

Suitable for: HVAC installers, property owners, builders and installers of standard ventilation systems in homes and smaller premises.

Industries: HVAC and ventilation, residential property, construction and renovation.

Frequently asked questions (FAQ)

Can the Vents-Group ventilation grille GRM-485 be mounted horizontally, for example on a ceiling?

No, the GRM-485 is intended for mounting on vertical surfaces only, i.e. walls. The gravity louvres rely on gravity to close correctly, which requires vertical installation for the function to work as intended.

Does the Vents-Group ventilation grille GRM-485 require any maintenance?

The PVC louvres should be checked periodically to ensure they move freely and are not stuck due to dirt or ice. No lubrication is needed, and the weather-resistant polymer coating on the frame requires no repainting under normal operation.

What sets a grille with a gravity louvre like the GRM-485 apart from a standard fixed ventilation grille?

A grille with a gravity louvre like the GRM-485 closes automatically when the fan is off, thereby preventing cold air and draughts from flowing back into the building, whereas a standard fixed grille has no moving parts and allows airflow in both directions at all times. The single, undivided construction at this size also makes installation quicker than on the larger dual-louvre models.