Extraction fan boxes for commercial ventilation

How to choose an extraction fan box

The choice of an extraction fan box mainly depends on the required airflow, duct diameter and system configuration. The size of the premises, number of air valves and use of the building should also be taken into account.

Duct length, bends and changes in diameter create pressure losses. It is therefore important not to choose a fan box based solely on its maximum airflow.

What airflow do you need for a ventilation fan box?

The required airflow should be matched to the size and use of the premises being ventilated. A small system with only a few air valves will not have the same requirements as a workshop, restaurant, office or larger commercial building.

The duct diameter must also be appropriate for the required airflow. Ductwork that is too small increases air velocity, noise and pressure losses and can reduce the actual performance of the system.

Extraction fan box or supply air fan box?

An extraction fan box removes stale air from the premises and discharges it outside. A supply air fan box works in the opposite direction and introduces air into the building.

Depending on the system design, extraction and air supply can be used separately or together to provide air renewal and maintain a balanced ventilation system.

Compact, low-profile or acoustic fan box?

The appropriate fan box format mainly depends on where it will be installed. A low-profile fan box makes installation easier where available height is limited, particularly above some suspended ceilings. An acoustic fan box may be preferable where noise levels are an important consideration.

Before choosing a model, also check the dimensions of the fan box, connection diameters, electrical supply and the access required for maintenance.

Ventilation fan boxes and commercial range hood extraction

Some fan boxes can be used for a commercial range hood, provided their specifications are suitable for the required airflow, air temperature and ductwork configuration. A commercial kitchen extraction system should therefore be sized according to the cooking equipment and extraction ductwork.

For installations requiring a dedicated smoke extraction solution, see our range of C4 ERP 400° fan boxes.

Need help choosing your ventilation fan box?

Send us the size or volume of the premises, number of air valves, required airflow, duct diameter and length, and the number of bends. We can then recommend the appropriate fan box and airflow for your installation.