What size of extraction fan and carbon filter do i need for my tent?

Extraction fans are rated in m3/hour

Heres the simple answer for some of the most common tent sizes.

0.6m x 1.2m x 2m = 115m3/hour

1m x 1m x 2m =160m3/hour

1.2m x 1.2m x 2m = 230m3/hour

1.5m x 1.5m x 2m = 360m3/hour

1.2m x 2.4m x 2m = 460m3/hour

2m x 2m x 2m = 640m3/hour

2.4m x 2.4m x 2m = 920m3/hour

So find a fan that meets the airflow needed for your area if it takes a 125mm/5inch fan then you need the same size of carbon filter and ducting.

If you want to learn how to work this out for yourself in any size of tent or grow room keep reading.

Firstly work out the volume of your grow space (length x width x height) then multiply this number by 60. This gives you the maximum amount of air you need to exchange each hour.

So for example a 1.2 x 1.2 x 2m tent gives you a volume of 2.88m3, multiply this by 60 and you have 172.8m3/hour.

At the moment, a 100mm (4”) RVK100A1 fan seems suitable for this scenario with an air moving capacity of 175m3/hour. However, it does not consider the impact of attaching a carbon filter and ducting…

To factor in the expected fan speed reduction of around 25%, multiply the original calculation by 1.33.

So 172.8m3/hour x 1.33 = 230m3/hour.

Other factors to consider.

- Add 20% for a warm attic

- Minus 15% for a cool basement

- South facing rooms will tend to be hotter than north facing rooms – increase the size of fan and use a fan controller for exposed areas

- Add 20% for long ducting runs and/or multiple bends

- If incoming air is 25oC or above then the room will become hot irrespective of the ventilation – an OptiClimate System or Air Conditioning Unit is the only solution

- Minus 25-30% for air cooled lighting