Sheesh! Some confusion going on here! Someone is quoting cfm(volume) & area in the same sentence. Here's the science!! To prevent heat build up, the room needs to have its air exchanged anywhere between 4x per min to every 4 mins. Most I know go for a min of once per min, I prefer a min of air exchange every 30 seconds, this removes heat but not humidity (essential). A carbon filter will reduce suction by 25% and as mentioned, bends can reduce suction by up to 15%. Since all fans are rated by cfm (cubic feet per min) or M3/H (cubic meters per hour) this is what you need to do. Calculate the volume of the room, length x height x width. A 600W light is good for roughly 1sqm or 16sq ft. Assuming the height of the room is 6'6" 2M, this will give a volume of 104cf (2m3) with no carbon filter or bends, exchanging the air once per min would need a 104cfm fan or a 120m3/h rated fan. Weather these are 4", 5" or 6" is irrelevant, it is the fan rating you need to know. Going solely by aperture diameter is like saying my dick is bigger than yours!!! and makes no sense at all. Fact not fiction. W
