HookdOnChron
New Member
I have a 1200 watt led in my 4 X 4 X 7 grow tent. How many cfms should my exhaust fan have? plus, how many minutes should i have between it turning on or should I leave it on constantly?
CFM's needed for 1200 watt
- Thread starter HookdOnChron
- Start date
Hi and welcome to 
Your space works out at approximately 112sqft. A fan that moves 250cfm should work ok in your space Imo. I would leave it on constantly. If cold temps are an issue at lights out you could shut it off for say an hour then on an hour and so on
Hope this helps
Your space works out at approximately 112sqft. A fan that moves 250cfm should work ok in your space Imo. I would leave it on constantly. If cold temps are an issue at lights out you could shut it off for say an hour then on an hour and so on
Hope this helps
JuanCarlos
Well-Known Member
The general rule of thumb is that you want to exchange the total volume of air in your room once every 2-5 minutes depending on where you look. Most growers run fans that move a bit more air than that. On the low side you would want a fan that moves at least 60CFM of air which most fans will do. For your lighting I think Mr. Am4zin has made a great suggestion. Also remember that you can always use a speed controller to throttle down a bigger fan, but if you buy a fan that's too small there isn't much you can do.
KbCobra
New Member
I leave all my fans on constantly. Breeze doesn't stop in nature at night, plus it continues to keep smell down. I have two fans in my 4x8 tent. One as an exhaust with a scrubber and the other just moving the plants
