Exaust fan

Hey guys, I would appreciate some help with something. I'm trying to find an exaust fan for my box, dimensions are 4' tall, 3' wide, by 3'deep. I need a fan but don't know exactly which one to buy? I also was wondering what cfm would be good? Can someone plz tell me where and what to buy. I need this help like yesterday! Thnxs guys

You can go with just one 250cfm fan at the top of your box, should be ample.
In addition to oscillating fans within the box, this should keep your temps down.
You should be able to get one at home depot or off ebay/online.

Good luck man.

You want an inline fan... something in the 200CFM range. Here's a link for some common brands. Stay away from the booster fans. http://www.plantlightinghydroponics.com/ventilation-fans-c-76.html

Inline fan huh? I guess if I had unlimited funds that would definitly be the one I'd get. But I guess I'm wondering if I should get a pc fan or house bathroom fan? And if so which one? Since I'm new to this I guess I need more info than others do so I understand which is the best way to go for the money? Thanks for the help so far.

Unlimited funds? Its $80 bucks for a 400CFM Inline...

Your going to need something bigger than PC fans to exhaust a box that size. I use 80CFM PC fans for intake, and a 415CFM Inline for exhaust, and my cab is the same size as yours.

frozencpu has some nice 250cfm fans for 24 bucks and they work very good. So extremely easy to mount/hook up to ducting.

Ok, yea I didn't think they were that cheap. Thanks for the help.

purplehazin said:

Unlimited funds? Its $80 bucks for a 400CFM Inline...

Your going to need something bigger than PC fans to exhaust a box that size. I use 80CFM PC fans for intake, and a 415CFM Inline for exhaust, and my cab is the same size as yours.

Click to expand...

Sorry for jumping in on the thread but can I ask.. How many 80cfm pc fans you are using for intake?? Only one??

I have a 4' x 9' x 8'H grow room and I have been using one of those duct booster fans and It worked fine, ran duct work to a vent on the roof. The only problem was I needed another booster once the humidity started to rise with the size of my plants.I have a fan pushing and the other fan Is pulling at the vent In my roof.

IstTimer said:

Sorry for jumping in on the thread but can I ask.. How many 80cfm pc fans you are using for intake?? Only one??

Click to expand...

Hi, I use 4 total. 2 in veg room and 2 in flower; both get exhausted via the 415 inline.

purplehazin said:

Hi, I use 4 total. 2 in veg room and 2 in flower; both get exhausted via the 415 inline.

Click to expand...

Cool, thanks for that.

I plan on using PC fans but Im hoping to go a little bigger than 80cfm, but If I can't find anything bigger (my resources are limited) I will think about 2 or more 80cfm.

My veg room is 4.7' x 3' x 1.3', and flower a little taller at 4.7' x 3.7' x 1.3'

Im still in the planning stages of my first grow setup, you can see it here:
https://www.rollitup.org/grow-room-design-setup/340777-grow-closet-plans-2.html

Ignore the first set of plans, they suck!! Post no.12 has my 2nd attempt.

Peace

i have a stanley blower fan that i use. but you need to be inventive to hook it up to ducting. it has 3 speeds. it takes air from the room and exhausts out 6 inch duct. i do not use any fans on the intake. it is an 8 inch passive intake and creates a nice negative pressure.

Just to let everyone know those stanley and other blowers identical to it are not acually pushing the CFM numbers that are advertised, some say 1200 CFM others are 3100CFM but they are actually more around 300 and 400. I have not a clue why they list them like that or where they are getting the numbers from but the actually ones are much lower.

Because cfm is a joke of a rating. You could take a 400 cfm inline booster fan, and it would be nowhere as effective as a 300 cfm vortex or elicent. The reason is that there is a tremendous difference between cfms and static pressure. The vortex/elicent type fans blow so hard with static pressure they will practically blow your hand off if you cover the exhaust port. A 400cfm inline booster fan (aka cheap) will have no where near the pressure/overall airflow. Trust me, I tried the cheap route at first (pc fans and inline booster) and the 6" elicent is probably the best investment I made. Despite the $200 price tag! Hope this helps!

Thanks for the help guys. It's really amazing how this was supposed to be something little. Now i can't stop trying to make it the best grow room possible.lol

Same here man, I started out thinking I was going to build a little CFL cab for $150, now Ive spent $600+ on a huge cab, HPS, fans, odor, etc

It is not that cfm is a joke of a rating it is that the companies are a Joke for listing their fans as double the cfm of what they really are.
a booster fan is exactly what the name says its made to BOOST airflow not be the stand alone system for airflow

I've done a test on the Temp.

I bought a cheapo temp gauge to test the ambient temp in the room I plan on growing in. (Not the grow closet itself but the room the closet will be in)

I got these readings...... 83F/28C!!!!! Ouch!!! and this is without any lights!! Am I right in thinking 75F is the ideal temp??

If the temp outside/in the attic is higher, am I kidding myself thinking I'll be able to drop that with fans alone and no air-con??

Geeezzzzz, who said this indoor growing was easy lol

70-81 is about the range you want with lights on... if you have C02 your plants could be in the upper 80's

Sorry for the stupid question but when you say CO2... Do you mean CO2 in a canister or CO2 from a fresh air intake??

I plan on running a fresh air intake from an uninsulated attic. Should be plenty of fresh air up there!!

I will also run a 250w cooltube to keep temps down.