I hear that if you multiply the dimensions, that will give you the CFM's needed.
So 4 x 4 = 16
16 x 7 = 112 Cubic Feet
So maybe we'd need at least 112 CFM to replace the air in that size tent/cab every minute...I'd imagine? Maybe even double, or 200+ CFM with a carbon filter attached (depending on the light/heat..probably more).
this area calculation was supposed to give the fan size that was needed to remove all the air in the space
in 10-15 mins or like at least 4-5 air changes per hour, this is grow book talk
this is to bring fresh air into the space not so much for removing heat from the light
so from the old grow book formula you want a fan that can remove 112 cubic feet in 15 mins or less
it works out that most 6 and 8 inch fans can remove the air much quicker than whats recommended
with air changes more likely every 5 mins or less, the faster the better
peace
