Ventilation Issues

ok so i have a small grow box, 21" by 23" by 24" i was running 12 cfls ( no plants yet ) but this got hot around 93F ok so i take 6 out and my temps crawled to about 91F being in the middle region and 88.7 on the floor.

my box has 2 80mm fans for ventilation not the best but all i could do. one works as an intake the other pushing out. i have one fan at the top front panel of the box and the other at the bottom back panel. then i have a 120mm fan pointing at the lights. temps are at 91 and most likely climbing slowly. so what should i do? i was reading that i should have an intake but rather both fans acting as an exhaust and the having passive intake. would this be a better option?

never realized cfls got this hot

If theres a way to place your fans where one of them pushes the air straight towards the 2 other exaust, that would help.

currently i only have one fan at the bottom back panel and one at the top front panel then a 120mm blowing at the lights

remove the fan from the intake and just have it a passive intake. try running just 1 fan as an exhaust and check your temps. you may need to use both fans as an ehaust, which would means another exhaust hole for the 2nd fan.

usually your passive intake hole is slightly larger than your exhaust, so a 6" exhaust would require a 7 or 8" intake hole depending on how strong the fan is. by sucking the air out will create a negative pressure bringing air in through the passive intake and should help remove the heat better.

you may need bigger exhaust fan. whats the cfm's of those fans?


oh and 12 cfl's in that box. lol sweet i hope you can get your temps down.

try turning the fan so it isnt blowing at the lights and see what happens. its blowing the heat around in the box instead of letting the heat rise to the exhaust.

thanks S&C yea ive only got 6 lights in there now and them temp reached 93 again. so ill take out the intake with out cutting another hole for now. if this doesn't work ill just add another exhaust hole and cut more intakes.

ok also turned off the circulating fan

temps are at 95 and rising now.

i think the light trap i had was cutting off a lot of the ventilation so i removed it. i hope this is the solution

so temps hover at 91 max with lights on a 66 with lights off.. big difference so its not like the box is in a warm area. to see the set up click here maybe this will help you guys figure out a solution

so to add more information

the 80mm pc fans push 31.65 cfm each, im guessing theres just not enough air flow or my setup just isnt right.

i found out that i have 5.59cu feet total. thats not really that much space. so whats stopping my fans from ventilating properly

do you have them configured where fans are pulling hot air from lights?

no im going to use pvc pipe to get the exhaust right next to the lights so it pretty much pulls the air out by the lights first. does that sound good?

cut another hole and run 2 exhausts at the top. passive intake

I think try the pvc by the light and if that doesn't cool it enough then your gonna have to cut some holes.

Get a bigger box. 2ft tall isn't gonna leave any plant room. With lights taking a min. Of 6" and pots another 6" . if you leave a gap of 3" you now have a whopping 9" to grow in.

420forme said:

Get a bigger box. 2ft tall isn't gonna leave any plant room. With lights taking a min. Of 6" and pots another 6" . if you leave a gap of 3" you now have a whopping 9" to grow in.

Click to expand...

Seen people get couple oz from pc cases which are smaller

Make sure yo don't have any tight 90 degree elbows and last options just get higher cfm fan