Carbon Air Filters

A quality carbon filter is an essential component of any grow room extraction system. Activated carbon is one of the most effective odour-elimination materials known — its vast porous surface area (up to 1,500 m² per gram) physically adsorbs odour molecules from the air passing through it, removing them from the extract before it leaves the building. Without a carbon filter, the characteristic aromas of an indoor grow are carried directly out of your extraction system into the surrounding environment.
How Carbon Filters Work
Carbon filters use activated carbon — typically derived from coconut shells or coal — that has been processed to create an enormous network of microscopic pores. As humid, odour-laden air passes through the carbon bed, aromatic molecules are physically trapped within these pores through van der Waals forces. The carbon does not chemically destroy the molecules — it simply holds them permanently, which is why carbon filters must be replaced periodically once their adsorption capacity is saturated.
Quality matters significantly with carbon filters. The density and grade of carbon, the depth of the carbon bed and the quality of the outer mesh all determine how effectively the filter eliminates odours and how long it lasts. We stock only carbon filters with verified high-grade activated carbon and adequate bed depth for their rated flow rate.
Sizing and Matching Your Carbon Filter
Match your carbon filter diameter and flow rate rating to your extraction fan. A 4-inch filter pairs with a 4-inch fan, a 5-inch with a 5-inch, and so on. The filter’s m³/hr rating should meet or exceed your fan’s maximum output. Pre-filter sleeves protect the carbon bed from dust and moisture ingress, significantly extending filter life — replace the pre-filter every 3–4 months and the main filter every 12–18 months of continuous use.
We have been helping UK growers select the right carbon filtration for their extraction system since 2017. Browse our full carbon filter range below.