Our range of centralized and commercial mechanical ventilation systems covers extraction fan boxes, roof extract fans, replacement motors and fan speed controllers to ventilate public-access buildings, apartment blocks, offices and commercial premises over the long term. Airflow rates from 250 to 4,600 m³/h across 74 available references, in single-phase 230 V or three-phase 380 V, EC or AC. Need a model compliant with the C4 smoke extraction standard? Head to our C4 400 1/2h motorised fan box.

Frequently asked questions

What is the difference between an extraction fan box and a roof extract fan for centralized mechanical ventilation?

The extraction fan box connects to a duct network and serves several rooms from a central point (loft space, false ceiling): it suits buildings with several premises to ventilate. The roof extract fan is fitted directly on the roof and extracts air over a long vertical network of several storeys: it suits extraction for tall buildings or large-volume warehouses.

What is a C4-certified fan box and when is it required?

The C4 standard requires a fan box or roof extract fan to keep operating under extreme temperature for a defined duration (for example 400°C for 30 minutes), a point often required in public-access buildings for smoke extraction in common areas. Several Nather and Cairox fan boxes and Saftair roof extract fans in the range carry this certification: always check the exact technical datasheet of the model before a project subject to regulations, as the standard never applies to the entire range generally.

How do I know if a replacement motor is compatible with my old mechanical ventilation fan box?

First compare the motor size (7/7, 7/9, 8/9, 9/7, 9/9 in our range), the number of speeds and the airflow indicated on your old motor. Double-inlet centrifugal motors, from S&P for example, cover airflows from 720 to 6,000 m³/h depending on the reference. If in doubt about a specific compatibility, it is best to contact us by email: contact@ventilsogood.com before ordering.

Do I need a single-phase or three-phase controller to control my mechanical ventilation system?

A 230 V single-phase motor is controlled with a voltage speed controller sized according to its current rating (A): the range offers models from 1.5 A to 5 A. A 380 V three-phase motor requires a variable frequency drive suited to this type of power supply, different from the single-phase voltage controller. Controlling the ventilation system is useful mainly for small installations, rarely for large ones which are often self-regulating or flow-regulated. Note that depending on how your ventilation system is used, varying the speed is sometimes not permitted.

What airflow (m³/h) should I choose for a centralized or commercial mechanical ventilation system?

Airflow depends on the number of rooms to serve and the type of premises, here are a few indicative examples: WC 15 m³/h, bathroom 30 m³/h, kitchen 100 m³/h, individual office of 10 m², minimum 25 m³/h, and a workshop of 30 m², minimum 300 m³/h. Our range covers 250 to 4,600 m³/h. The site's faceted navigation lets you filter by brackets (0 to 2,000, 2,000 to 4,000, 4,000 to 6,000 m³/h) to quickly isolate relevant models, bearing in mind that the duct network (length, elbows) always reduces the actual airflow available compared with the stated airflow.