How to Choose an Extraction Fan and Carbon Filter for Your Grow Tent
Good extraction keeps your grow room's temperature and humidity under control and keeps odour in check. The three parts of the system are the fan, the carbon filter and the ducting, and they work best when they are matched to each other and to the size of your space.
Step 1: Start with your space and lighting
A common rule of thumb is to size your fan so it can change the air in your tent or room roughly once a minute. Fans are normally rated with nothing attached, so allow extra airflow for the resistance of a carbon filter and ducting. Heat from your lights matters too: more lighting means more air needs to move.
Step 2: Match the diameters
Fans, filters and ducting come in standard diameters (100mm, 125mm, 150mm, 200mm, 250mm and 315mm). Keep the same diameter all the way through the system. Stepping down with a reducer can restrict airflow.
Step 3: Choose a fan size
Our complete extraction kits are listed for these lighting set-ups. They are a useful guide when choosing a fan size:
- 150mm kits: 1 x 600W HPS set-up (RadAir 500m3/h and Phresh Hyperfan Stealth V2 options)
- 200mm kits: up to 2 to 3 x 600W HPS, depending on the fan (RadAir 850m3/h, Can Iso-Max 870m3/h and Phresh Stealth options)
- 250mm kits: 4 to 6 x 600W HPS, depending on the fan (RadAir 1500m3/h, Can Iso-Max 1480m3/h and 2310m3/h, Phresh Stealth and AirFan Thermo options)
- 315mm kits: 6 to 10 x 600W HPS, depending on the fan (RadAir 2300m3/h, Can Iso-Max 3260m3/h, Phresh Stealth 3100m3/h and AirFan Thermo 4250m3/h options)
Step 4: Add a carbon filter
A carbon filter removes odours from the air you extract. Choose one that matches your fan diameter and airflow. Filters such as the Can-Lite list a recommended lifespan of around 18 months, after which the carbon should be replaced.
Step 5: Keep the ducting simple
Keep duct runs short and avoid sharp bends. Flexible ducting restricts airflow on tight turns, so use a rigid bend where you need to turn. Secure every joint with clips or clamps.
Step 6: Control your fan
A fan speed or climate controller lets you slow the fan down when the room is cool and speed it up when it warms, keeping conditions steady and reducing noise.
Shop the range
Not sure what size you need? Visit us in Rainford or get in touch and we will help you choose.