So my grow tent is 48x24x60"- does anyone have any idea what kind of exhaust fan would be best for it to remove a little heat from the tent, right now I just have 2 fans in there but I need to get an exhaust fan to bring the temp down about 5 degrees.
It all depends on the lighting and heat. They make 6 and 8 inch Duct fans . You might also think about an exhaust filter to cut down on smell.
I’m running 425 watts with cfl lighting. The temp usually (tries) to stay about 80-85- which I have read of people who do just fine in that heat- although I would really prefer it to be around 60-75 degrees…
I have a regular fan and a 6in duct fan but I’m not sure how to use the duct fan lol… 
Is it suppose to blow air in or take air out?
They work either way. Put the in fan on the bottom and the out fan up top.
60 is to cold.
IN that small tent, a 4" vortex fan would do just fine.
1 Like
Ok thanks 
appreciate the help
In my experience go big. 8" Hyper-fan with speed control.
You can turn the fan down and it’s very quiet.
Make sure you have enough intake if your pulling from the entire tent as opposed to the light only.
The formula is for every 300 CFM of fan you need about 144 sq in of intake area.
I started too small with a 4" fan.
Go big because it’s good to have lots of ventilation with hot lights.
So I just noticed ofor the size of the tent wrong it’s actually 48x24x60 …
If that makes any difference lol
This is what I am using in my 48x48x80 inch tent:
6" 440 cfm extractor fan with variable speed control and carbon scrubber, venting out through a roof vent.
6" 240 cfm intake fan with variable speed controller, pulling from the front room for co2.
I went larger on the exhaust due to pulling through an air cooled light and carbon scrubber.
It moves a ton of air, thus the intake fan as well. Holds my temps at 78f degrees with ease no matter the indoor or outdoor temp. As has been stated, I highly recommend getting variable speed controllers with them! My exhaust is only running at 50% and intake about 40%. Even at these low settings it sure makes the tent material suck in!
I have the exact size tent and used one 4" fan at the top and it worked well. I use a LED that actually used 275 watts (rating was 432 watts) and I had a little problem with heat in flowering. I also had some smell problems so I got another 4" fan and filter. I placed one on the bottom for pushing in cooler air and one on the top for taking out the warmer air. My temps came down and the smell of the flowering went away. My neighbors walked right by my 10’ x 10’ room with the door open and did not smell anything at all. Kept my ladies cool and no smell! Hope that helps. Good Luck growing.
Jerry
There is a formula to measure you “cfm’s” needed for you grow space. let me know if want formula ?
I curious as to the exact formula! My rate or exchange is excellent right now but I love learning new things 
Yes that’d be great! Please share lol
I know shred put one up a little higher but I would like to learn what everyone uses
Awesome thanks for the info!
I just ordered a 4" attawood quiet blower from Amazon … I will most likely have to control smell, but so far I only have my one Northern Lights plant (5weeks old) until I get my seeds from The Single Seed Centre; so I will wait till flowering gets a bit closer to actually buy the filter.
The temps here in New Mexico are starting to drop a bit lower so now my temp should be going down especially with the new fan lol
Here’s some pics of my 5 week old
Okay glad I know now, that’s what I thought but I honestly didn’t know lol
Ok you got it. I just ordered: Amazon.com
Also, okay I won’t let it get to 60 lol
“(site)” “(site)” “(site)” - let me add that this site has good information also. The weed Farmer.com might be one to look at all so
Your air exchange should not longer than a few minutes meaning - out with the bad ait in with the good air. will get back to you with cfm formula today
Sweet thanks Steve!
Best regards
Kayla
“cfm” is the total cubic feet of air that should be exchanged every minute. cfm is located on fan box - at present looking for formula for, Size of your grow space?