Computer fan mounting for ventilation ...??

Im installing 2 computer fans for ventilation because my box is getting to hot.. im growing with cfl's. so i want to install one of my computer fans mounted on the right side lower right panel , cooling fan will go there and my heat exhaust will go back panel upper left region is where ill mount my vent fan.....

my question is which way will the fan have to turn to be sucking heat out not blowing it in.?? should i make 2 vent holes one top and one on bottom other side ??? if my temps are like 76-88 F range.. or will one computer fan pull most of the heat out if im using cfl's which arent that hot in the first place??

First of all don't kid yourself, CFL get plenty hot, the bulb doesn't but the ballast (Base) does. If I were you I wouldn't use a fan for the intake, i would just fashion some light proof vent holes and use both fans as exhaust. makes it all simpler. if the fan is blowing and not sucking flip the whole bugger around.

thats what i did in the first place mate but that seems not to work so i went with something i heard was ok just wanted to know alittle more about it before i go through with the whole mounting issue.

my question is still which way does the computer fan face for ventilation purposes? not cooling. thats easy. lol.

NoDrama said:

First of all don't kid yourself, CFL get plenty hot, the bulb doesn't but the ballast (Base) does. If I were you I wouldn't use a fan for the intake, i would just fashion some light proof vent holes and use both fans as exhaust. makes it all simpler. if the fan is blowing and not sucking flip the whole bugger around.

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So having 2 exhaust is better than having 1 intake and 1 exhaust?

no u always need cool air bringing in fresh O2 for you ladies.... just wanted to know if it was good having an extra vent??or is it unbeneficial.

I'll be waiting to see what you do and the results. I have 7 cfls in a small box and temps are up in the 80'.s

you need both intake and exaust if you use both fans for exaust cut two equal or larger holes for passive intake

hey why want you get another fan an have two exaust and one intake.

I have 3 comp fans total yay! having cannabis in a hot environment isnt good and shouldnt be ignored, i ignored it once and lost 38 day flowering huge massive "bigbud" strain. IT SUCKEd biG time ! so when i heard comp fans were ...i say aloud only to cut the aggrivation to a minimum lol, i was excited because i have them lying around and it was just what i needed! low sound, and it does its job. ne ways im going to mount one up high in left top corner of the box, and then ill have the cooling fan on another wall mounted towards the doors but kinda like in the middle so you get "cross-breeze" .

where should i put the second exhaust fan.?? lower /// higher ??

on the bottom of the other exhaust fan?? same wall ...be specific this is a very important aspect of your grow setup.

lower one sucking in upper one pushing out heat rises

1 fan is bigger and will be used for exhaust, the other small 2 are about the same size, if i use one of them to ventilate as well as the big one will it make my heat go down? and why would i mount it like that padishah, it would just make a circle of hot air?......

the lower one will suck in cooler air while the upper one will suck out the hot air cooler air is generally closer to the floor

depending on your area you want equal intake and exaust so you dont create a vacume you can also use passive intake where you just have some lower holes to allow the air to be sucked in

I have a similiar situation I got a 2x2 box what I did Is i mounted to small computer fans at bottom for intake side by side inside the box on the ountside of the box i went to home depot got metal ducting. Its like a connector piec that one end is rectangular you can mount that on the box it has a small angle mount your 6" flexible duct to that. Takes care of intake (make sure it is sucking in) For exhaust mount bigger fan inside the box blowing air out (put it has high up as you can) use the same type flashing on outside box hook your 6" flex duct and your good. I didnt do no vent holes I am using a 250hps and 2 2foot fluro temps stay round 72-76 If you still having issues increase fan size or add a small circulting fan inside box blowing towards light

dont forget to seal use sealant round ducting on outside box Sorry bout spelling

You ALWAYS want more air being EXHAUSTED than being brought IN!!! Thats the reason for a PASSIVE intake. If you remove air from a box it has to replace itself. If replacement air can't get inside the box it'll create a vaccum and the box would implode (more likely the fan would burn out from working too hard, and some air would be forced back in around the exhaust fan blades. This would likely sound like a huge fart!). Cut a couple holes at the bottom, now new air can get in to replace the exhausted air. If you don't have large enough passive intakes your negative pressure may be too great, and the air will be heated too much before it exits the box. It's better to have more open area for passive intake and a small fan INSIDE the box that blows the air in the box around gently, mixing it up and keeping the cooler air at the bottom blowing upward. If you dont have the room to cut larger or more intakes, you can use an intake fan, but it MUST move less CFM than the exhaust. the air in your box is being heated by your lights, you definately want to move that air out faster than you are bringing new air in.

pacman is right but the fans i used, the two small ones together(intake) still equaled less cfm than the larger one for outtake just make sure if you mount the two together the cfm rating is lower like pacman said

use all three for exaust.

Chumlie said:

use all three for exaust.

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if i use all three then there will be no cool air coming in! the plants need oxygen to survive i cant just bake them in an oven and expect them to come out lookin like mrs.fields was there. so i will use one for exhaust for now and one for cooling on the opposite side blowing a breeze cross the whole box and across the lights as well.

i added an oscilating fan just for better stem support, and to exaggerate artificial wind a bit..............................................................



ok i just mounted the exhaust fan and its working pretty good i guess , connected to a 12V DC 1.5 Amp . havent noticed any real drop in temp yet...will check again in the morning, on another note i want to hook up the other computer fan to the same 12v connection , all i need to do is grab an old cell charger just for wire to extend the wires to reach the 12v ...is this ok or do i need specific wire...????

Greengoof said:

if i use all three then there will be no cool air coming in! the plants need oxygen to survive

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They need CO2 to survive, and just use a passive intake and you will have more than enough air coming in and out...with 2 fans you should be very fine if it's in an air conditioned room