Extraction fan box for commercial kitchen hoods: the remote motor that quietens the kitchen

An extraction unit is a housing containing the hood's ventilation motor, installed remotely (in the ceiling void, loft space or outdoors) rather than directly inside the hood. Air carrying smoke, grease and odours passes through the hood filters and travels via the duct to the fan box, where it is extracted and discharged outside. The practical result: motor noise leaves the cooking zone, which genuinely changes the atmosphere during service. This solution suits restaurants, snack bars, food trucks and catering kitchens that want a quieter kitchen without sacrificing extraction performance.

How to choose your extraction unit

Three criteria guide the choice within our range of extraction units:

• Airflow (m³/h): our motorised units cover ranges from 720 m³/h (small compact unit for mechanical ventilation or snack bar hoods) up to over 22,000 m³/h (three-phase SAFTAIR range for large kitchens). In between, the 7/7, 9/9, 10/10 and 12/12 formats cover intermediate airflows.
• Power supply: most of our units run on single-phase 230V, convenient for a standard connection. The higher-airflow SAFTAIR 400° series require three-phase 380V, which your electrician will need to confirm is available on site.
• Noise level required: if the kitchen is small or close to the dining area, choose a sound-attenuated unit (7/7, 9/9, 10/10, 12/12 attenuated references in our range) rather than a standard unit.

The right choice also depends on the length of your hood, the type of cooking (frying, griddle, wok) and the diameter and length of the ductwork: the longer or more bent the ductwork, the more pressure losses reduce the airflow actually available compared with the rated output.

Motorised fan box or unmotorised fan box

Two options sit side by side in the range: the motorised fan box, ready to connect, and the unmotorised fan box (or plenum box), an empty casing into which you fit the motor of your choice. This is a useful solution if you are reusing an existing double-inlet centrifugal fan or want to choose the motor independently of the box. For example, we offer the unmotorised fan box for 7/7, 7/9, 8/9 motors, the fan box for 9/9, 10/10 motors or the small unmotorised fan box / plenum 350x350x380.

F400/120 extraction unit for smoke extraction

Some units in the range carry the C4 smoke extraction rating and are stated to operate at 400°C, such as the compact 3600 m³/h unit, 400°/2h rated, the Tecnifan 9/9 F400/120 and 10/10 F400/120 units, as well as the three-phase SAFTAIR 400° series (from 2500/4500 m³/h to 6000/22000 m³/h). These units meet smoke extraction requirements specific to certain types of premises: always check the exact regulations applicable to your project before considering a model compliant, and do not confuse the C4 rating (400°C for 30 minutes) with the F400/120 classification (400°C for 120 minutes), the two are not interchangeable.

Supply air units and accessories

Beyond extraction, the range includes supply air units with G4 filtration, from 2000 to 4000 m³/h, useful for compensating extracted air with controlled fresh air intake. Complete the installation with a G3 filter box for pre-filtration, a flexible connecting sleeve to isolate the unit from the ductwork, or self-adhesive acoustic insulation to further quieten the unit.

Points to check before ordering

• Duct diameter and length: long ductwork or several elbows increases pressure losses, so the airflow actually available at the end of the line is lower than the unit's rated output.
• Air intake: efficient extraction needs sufficient fresh air intake, otherwise the real airflow drops and the resulting negative pressure causes noise.
• Power supply available on site: 230V single-phase for most units, 380V three-phase for the higher-power SAFTAIR models, to be confirmed with your electrical installer.
• Weight of the unit: some models exceed 80 to 100 kg, so plan suitable fixings (brackets, heavy-load support consoles) and access for handling.
• If a thermal cut-out trips after 10 to 15 minutes of operation, check the ductwork for excess pressure, the air intake and the power supply before suspecting the motor.

Complete your order with

Consider the accessories that make installation and durability easier: installation kit with threaded rods and fixings, heavy-load support bracket, CR1 fire-resistant cable for installations subject to the C4 smoke extraction rating, and inlet/outlet adaptor parts to adapt the connection of your unit. You will also find our commercial hood motors if you are looking for a double-inlet centrifugal fan rather than a remote extraction unit. VentilSoGood supplies this equipment but does not carry out installation: fitting must be carried out by a qualified professional.