I put a 445 cfm on a clone tent and it sucked the sides in quite a bit..

I'd go with 2 fans.. one for your light with it's own intake and exhaust, running when the light is on. A second fan to vent the tent with a temp controller. This would let you use a smaller fan for the tent itself. A 245 cfm can fan would do that nicely completely cycling the air in the tent just less than once per minute.

Last.. don't think heat isn't an issue, with a 1000 watt HID light in a tent you can cook some plants.

Peace, Farmer Rich
Farmer Rich Reviewed by Farmer Rich on . Exhaust??? I am about to purchase a 224 cubic feet tent. I am going to be cooltubing a 1000w hps light so heat is not a big issue. I am, however, curious about keeping the air inside the tent from getting stale. I will using an inline exhaust fan that has a rating of 424cfm. My tent is in a 22x22 room and I was wondering should I bring in air from the outside my house via ducting or will the air from inside my house be ok? Also, should I leave the exhaust fan on continously or should it go on and off in Rating: 5