Closet ventilation HELP!?

Yo! I've got a ventilation problem and would be very grateful if someone could please help me find a solution.
I'll post some pics of the closet below so you can see how its setup. got 2 300w duel spec CFLs, carbon filter>fan>ducting>out the door
it shoots up to 30 degrees C in there with both CFLs, the 4" fan and the household fan all on.
please help!

I would try to move the table fan lower to get cold air, You could take the filter off and try to use the duct fan to pull cooler air in.

Hey bud, moving the small fan to blow more up and threw the canopy. Or you could get a smaller fan in the to blow over your lamps to move that heat pocket around to get the inline fan to pull it out.

I agree with above reply, ideally u wanna be getting cooler air in too - I'd say if ur able to/allowed to, etc then best thing is to cut 2 small circular holes near bottom corners, or 1 long, thin horizontal hole at bottom of that cupboard door & fit a simple plastic louvred vent into it. (like what u'd use on an airing/drying cupboard door - probably cheap as shit in hardware shop)

That would allow abit more of the cooler air at floor level to creep in & u can always put pair of tights over back of vents (on inside of door) to stop insects getting thru the vent slats. Also, if ur CF & extract fan are working well enough, then u shouldn't really have to worry about smell creeping out these little holes at bottom either.

Also, as a side note, i'd say if ur only just hitting literally 30 degrees then that should probably be ok - most plants of sturdy stock should be fine with a slightly high temp. May just have to water them a little more & be careful of related humidity rises. But if its regularly going over 30, and anywhere near mid/late 30's then it could put a dampener on their growth rate.

U didn't state if the temps are causing growth problems already but unless they are then i'd say don't worry too much.

Tho as last poster just said, another quicker & cheaper thing u can do is just make sure the oscillating fan is hitting them direct, as the surrounding cupboard temp doesn't matter too much if they're in a cooler breeze all day.

Good post ^^^^

How strong should the airflow out the end of the ducting be? i have a feeling my fan may not be up to the job. i only get very mild airflow coming out the vent in the door...

it stays at a nice 25-26 degrees C in there with the door left open slightly and no outlet fan on but as soon as the door gets shut it shoots up to 30 degrees C. I've never left it long enough to see if it goes above 30 i normally panic and leave the door open a crack.


do you think a couple of vents in the bottom of the door would be enough, its not just going to heat up the room that the closet is in so hot air just gets blown out then sucked back in again is it?

very helpful posts, thanks!

Those brightwings can get pretty hot in that little of an area. Usually any unexposed metal (usually for support) on them gets really hot. As others have said, try aiming a fan upwards shooting past the lights and up towards your exhaust.

blacksun said:

Those brightwings can get pretty hot in that little of an area. Usually any unexposed metal (usually for support) on them gets really hot. As others have said, try aiming a fan upwards shooting past the lights and up towards your exhaust.

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I've lowered the table fan so that it blows under the reflective shades and that sure keeps the bulbs a lot cooler but the fan has to be at the back below the filter due to lack of space

still though, if i close the door it shoots back up to 30 degrees C within 5 mins.

You need a stronger exhaust fan,vent holes at the bottom and a smaller interior fan to blow straight up on the bulbs.GL.peace

Lol! it is easy to panic about them but they are pretty hardy - tho certainly its good u are cautious & monitoring them as its the best way to keep them continously running well.

Firstly, i dunno about airflow speeds u need as depends on fan speed & dimensions of cupboard - one of the threads about vents on here or on google will have the equation for working out how much air u need to shift for that space. Tho Bi66er's probably right - if ur fan's only 4" then it'd need to be some top quality German, industrial spec one as that cupboard is quite big!

But i'd say try giving it an extra 45 - 60 mins extra after u close door to see how much it does go up. From what u describe, i must admit i suspect it will keep rising up still but if it stays round 30, then just see how ur plants get on with for a few days & if theyre cool, it shouldnt be a problem. Just try it & see - as long as it dont go stupid high,like 40+, then the plants won't be damaged by an hours exposure to it.

And little vents at bottom should help abit, tho obviously only if the outer room is cooler than the cupboard to begin with. And dont worry bout the air u extract from top - it won't settle down & get sucked back in cause of warm air rising effect.

As far as how much air flow you need.. A good rule of thumb is to have a inline fan that can move the amount of air space in 5 mins. IE 3000 cubic unit room should have a 600 cubic unit fan.

But I would say to get more air in with the vents at the bottom. I would filter the air some how. I just went to the fish store and got some make your own filter for a water pump. Then I just put it on the inside of the room to scrub the air before it enters the room.

my 4" fan can move the air out of that closet in 25 mins, witch obviously aint enough. but until i get a bigger fan, i've taken 1 light out & adjusted the duct work to allow for smoother airflow & it stays at 26 degrees C in there.

a better fan and some intake vents are certainly on the cards after xmas though.

cheers for the help peeps!

Sensi123 said:

my 4" fan can move the air out of that closet in 25 mins, witch obviously aint enough. but until i get a bigger fan, i've taken 1 light out & adjusted the duct work to allow for smoother airflow & it stays at 26 degrees C in there. a better fan and some intake vents are certainly on the cards after xmas though.

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Sounds like a plan!
One air exchange every 25 mins is too low.
The temperature rising with the door closed is a good clue you need more air coming in.

I also like your ductwork improvements. You may also want to revisit your filter support; you could be blocking ~10% of your intake with your bungee cords. I got mine supported just on the edges so as not to block the carbon intake area. Another idea for minor improvement - you could consider a short run of solid ductwork prior to the flexible duct for the door opening. You add a lot of resistance with flexible duct. I know you need some for your door opening, but a little less flex duct might help your air flow a bit.