how big of a fan would i need to exhaust a grow room thats about 3'wX2.5'dX7'h. my temps are ranging from mid 80's to low 90's. i just want to get a good fan the first time and not waste any money. Also, i would like this fan to be able to cool a homemade 4'X4'' box using a 400 watt mh/hps....Thanks guys. jut want a fan that will work with my closet grow now, and one so i dont have to get another one when i build my grow box in the next few months.
Check the first page of the grow journal in my sig. There is a pic of my exhaust fan setup for a similar size closet with a 400w HPS. I use a 4" Brinkmann "Windy" fan that I got at Plantit Earth for $30. I use one up near the top of the space for exhaust and on near the bottom for intake. I was worried that it wouldn't be enough airflow but those little guys move some air and both work perfectly for my setup. I do have 2 other fans for circulation in there but my temps stay right at 78 all day. Pretty quiet too.
I should add the disclaimer that ventilation is extremely important andsome people may tell you that more is necessary...all I know is that this setup has worked perfectly for me. Something you need to take into consideration is how far you need to move the air through ducting. In my setup the exhaust fan is only pushing air through about 6" of ducting into the next room. my 2 cents...hope it helps.
Thanks bro, thats does help. any idea what CFM your fan is? i may also try to find a cabinet instead of building my own, just have to find one that will hold my 400 watt light, and not get too hot. if all else fails, i'll build my own.
No worries man, glad to help. Sorry but I have no idea on the CFM of those little guys It's probably not alot. One other thing to take into consideration is the climate that you are in. I am pretty fortunate that I live in a coastal climate and it pretty much stays 55-65 year round. I actually wish it were a little warmer but my plants dig it
I live in Reno, where its cold as hell during the winter, and gets pretty hot during the summer. And there is little to no humidity during the summer. So during the day lately the temps have been in the 90's, and my grow room doesnt seem to go over 92 at very most, which i know is too hot, but i cant seem to cool it much more. its been staying today around 85-89, and yesterday it was a lil cooler and was around 84. During the winter heat wouldnt be much of an issue i dont think, but this summer is going to be a bitch.
Oh, and about the fan, no worries bro about not knowing the cfm. Im planning on slowly getting all the supplies i need to run a good grow room ie: an inline fan or blower for an exhaust, and ducting and all the needed ventilation and temp control things.
Sounds like you have the right idea and plan on doing things right. I posted some pics in your journal to give you some ideas. Your climate is quite a bit warmer than mine so you will probably need an inline fan or blower, but the idea is the same. Good luck and I will see ya in your journal!