I built my grow area in the dead space above the rear stairs at my house - it measures 3\' x 4.5\' x 5\' (67.5 cu. ft.) and is accessible with a set of fold down steps. I cut a 14quot;x6quot; (84 sq. in.) intake vent coming from inside the house and a 10quot;x10quot; (100 sq. in.) exhaust to the attic with an array of four computer fans pushing a total of 156 cfm. This fan setup replaces the air 2.3 times a minute with additional cool air coming in from a splice off an a/c duct (the 6quot; tube coming from the ceiling).