Any free way to drop temps in a grow room?

Ok so my temp hit 100 today,i have a pretty decetn sized closet with a 400 Watt HPS and a fan in there.Buying homemade carbon filter equipment tomorrow for making one.got afan for that.Have no way to cut holes in any of the walls because theres no way of knowing where the electrical wires are.
Any good way to cool down a room?I heard something aboitu frozen water bottles,anything?I just want it to get to 90 not 100

u need to get the hot air out, so an inline duct fan. theres no free way, unless u pump free cold air inside

what if i cut a hole in the wall towards the hallway and put a window fan in it would that work?

okay, r u always keeping the closet closed? I also grow in a closet with a 400 system, with a fan on the wall, no fancy or other ventilation and a box fan blowing on the plants from the outside of the closet a few hours a day and the closet open the entire time. Only for that reason does it never go over 92, although with the lights on most of the time it is about 82. Lights out much lower about 72. U might just need to keep the closet open for better ventilation. Now when I was on 18/6 my closet was closed during some of the lights on period, but even then never has it gotten about 92. Hope u get some good advice to control ur temps

yea im gonna make an exhaust kinda and also keep the closet open more!!

open that door up!

im gonna exhaust the heat into the hollow space in my walls!!!

does the closet have a light fixture mounted in it? If so, I'd turn off the light switch in order to not shock myself, unscrew the light fixture and see if you can use a pocket mirror and flashlight to find a spot where there are no wires in the ceiling, then buy a decent CFM fan 300+ and exhaust through the ceiling. Of course when you move out or convert it back to something other than a grow space you'll have to patch it up. But it's better than killing a sweet crop because your temps are too high. Also, Co2 is an option when dealing with higher temps so I've read, but must admit I've never used it so cannot offer an authoritative viewpoint. Hope this helps!

the closet does have a light but theres no light switch.and that would work but i dont got a fan besides whatever i can buy tomorrow at home depot or menards.whatever they ahve that is decednt.

Man cmon now use you brain. Make a hole in the drywall and look cut a small hole with a hand saw its easy you don't need any power tools., I also doubt there are any electrical lines at all that you could hit in your closet.

yea well on one wall on the opposite side of the closet theres a outlet,and theres also the fuse box on one wall

gobears4eva said:

im gonna exhaust the heat into the hollow space in my walls!!!

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IMHO, BAD idea!
First that wall is basicly a sealed box. 2X4 each side for fame from top to bottom, and goes all the way from ceiling to floor. Probably has a fire stop in there somewheres by code from the builder.
you'll be inducing "warm / dark / and moist. That is prime conditions for mold and rot. Left long enough the sheetrock will disolve.

And even if it did work,, what about the smell in flower?? The whole place will smell like a Hemp Fest and would take a very long time to get rid of it.

yea,i decided not to do it,and just to keep the closet door open during lights on cycle.

theres no windows in my closet or i would open one