I have 2 identical tents 76"x76"x76". Since the fall, each has had 4-600w lumatek dimmables. I was running a 6" 424cfm fan as the exhaust in each (carbon scrubber>lights>out of the tent). That worked fine until the winter cold broke. Since then, I have dedicated the 6" fans to the lights only. Air from the room that the tent is in is drawn in and through the lights and exhausted out the other side. I added an 8" 742cfm fan as a general exhaust in each tent (drawn through the scrubber and out of the tent). This has helped A LOT! I recently upgraded the room's exhaust to a 12" 1060cfm fan from an 8" 590cfm so I think that will help a lot cooling the ambient temperature of the room, so my fans have a cooler air intake. With these upgrades, I am sure that until the heat of the summer really hits, this will work fine. I am just wondering though, what formulas are out there that factor in having a dual exhaust set-up like mine. I'm sure that come mid-summer, my 600's will have to be dialed down to 400 each. I just want to be sure that these modifications will get me through the summer. The overall growing area is the entire basement of the home. The basement is separated into three rooms. The two smaller rooms are each about half the size of the larger. The flow of air is into the first small room via a window > larger room via an 8" 745 cfm fan. An active 6" intake into the other smaller room > larger room via an 8" exhaust (just for the lights-3 1000w) and another 8" exhaust for the room. Large room has another window for an intake, and is exhausted via the new 12" fan. I hope this makes sense. I figured it would be wise to include the general layout. The total wattage, if everything is running at the same time, is about 11K watts.
I struggle in the summer big time, i have 2 6oo lumateks. I think you got do what you think is best until you find the right setup for summer months, trial and error. I use bigger fans then i actually need and then plug them into dimmers so i can turn them up and down when needed.