What is a carbon filter box for a commercial kitchen hood?

A carbon filter box (Coal bin) is a filtration system installed on the extraction ductwork of a commercial kitchen hood. It removes or greatly reduces cooking odours before the air is discharged outside, which is particularly useful when the discharge point is close to housing, shops or neighbours sensitive to cooking smells.

The unit combines grease pre-filtration with activated carbon cartridges, the heart of the system. Please note: activated carbon treats odours and some organic matter, but it is not designed to remove smoke from wood fires or barbecues.

How does an activated carbon filter box work?

Air drawn in by the hood first passes through a grease filter, which protects the activated carbon stage downstream. It then passes through the carbon granule cartridges, which trap a large proportion of the molecules responsible for cooking odours.

Actual effectiveness depends on airflow rate, type of cooking, the quantity of activated carbon and its level of wear. There is no permanent miracle solution: the carbon needs to be replaced regularly to maintain effective filtration.

Types of carbon filter box in the range

Our range of standalone carbon filter boxes runs from the base 5-cartridge unit (CH5 model) up to the heavy-duty 48-cartridge installation (CH48 model, 14,400 m³/h), with intermediate steps at 6, 9, 12, 18, 24 and 32 cartridges. The more smoke and odours your kitchen produces, the more cartridges you need.

For smaller setups, the mini activated carbon filter box with double G3 filter is suitable for occasional use or for filtering odours from room ventilation (gyms, shisha lounges, etc.). Conversely, for heavy loads (fryers, griddle plates, woks), it is best to go for a higher-capacity range: a mini box with a simple G3 pre-filter is not designed for this type of use.

In terms of fan arrangement, some units have the fan built in (6-cartridge box with integrated fan), which simplifies installation by combining filtration and extraction in one unit. Others operate as a package with a dedicated double-inlet centrifugal fan, for example in 9/9, 10/10 or 12/12 configurations, all powered by 230 V single-phase. A carbon filter box without a fan remains an option if you already have a suitable fan on your ductwork.

Carbon filter box comparison table (standalone units)

How do you install a carbon filter box?

The odour control filter box is installed on the ventilation ductwork between the hood and the outside discharge point. Depending on the configuration, the fan can be fitted inside the hood, built into the filter box, or installed in a separate fan housing: moving it away from the kitchen generally reduces perceived noise.

The filter box must remain easily accessible so the grease filter can be checked and the activated carbon replaced. VentilSoGood supplies the equipment but does not carry out installation: most of our customers fit their own filter box using our video tutorials. The only requirement for the warranty is that electrical connections must be carried out by a qualified electrician.

Points to check before ordering

• Number of cartridges required: this depends on the length of your hood, the number of grease filters and the type of cooking (fryers, griddle plates and woks produce more grease and smoke than a standard hob).
• Extraction airflow: this should be checked against the actual airflow of your fan or package, taking the ductwork into account (length, elbows, pressure losses), not just the catalogue figure.
• With or without fan: if your ductwork already has a suitable fan, a standalone carbon filter box is enough; otherwise, a package with an integrated fan box (9/9, 10/10, 12/12) simplifies installation.
• Planned maintenance: activated carbon loses effectiveness over time and must be renewed regularly; make sure the filter box remains accessible for this.
• Type of cooking: activated carbon does not treat white smoke or barbecue-type cooking fumes, and should be reserved for typical kitchen cooking odours.

Maintaining the filter box and replacing the activated carbon

The grease filter protects the cartridges and should be checked regularly. The activated carbon should be renewed as soon as its effectiveness against odours decreases, since it does all the work.

You will find all the consumables you need on our site: the grease filter, replacement activated carbon cartridges and activated carbon in 25 kg bags to refill 6 cartridges.

Need help choosing your carbon filter box?

To determine the right model, let us know the dimensions of your hood, the number of filters, your cooking equipment, the airflow of your fan, and the diameter and configuration of your ductwork. This information allows us to recommend the odour control carbon filter box best suited to your installation.