How do I fix the heat in this room? (Diagram included)

Sorry about the artwork, it's the best I could do. The 3'x3' may me a little bit of an overestimate too. This is my first grow after extensive research. Everything is set up minus a few finishing touches with wiring to make everything look nice and neat. In the diagram, the ducting is running out the top of the enclosure to the fan and CF which is actually right above the grow, I just didn't draw it that way. I am running a 600w HPS. I have 6" ducting which is just dangling down and facing the light. I would get a cooltube or a cooled hood of some sort, but I can't fit it in. Everything is fitting perfectly at the moment. The ducting runs up through the ceiling to a 250 cfm canfan then out through a CF. I would hang the CF in the enclosure and pull air through it and out, but I don't have the room and not sure if it makes a difference. Either way, I can't seem to the the temperature to drop below 90˚. I have no passive intake yet, because I am debating where to drill it, but that can't be the problem, because the temp still won't drop below 90˚ while I have the door cracked open pretty wide. Any ideas or suggestions?

you want the ducting to be above the light not below it....heat rises....especially the heat from the lamp.....you need to pull out more heat than air coming in....by placing the exaust end below the light your taking out good air and letting the heat rise and collect.also you need to put in a passive intake...just pick a spot and drill....just make sure its not easily exposed to light....and at the base of the cab.......also.you want the passive intake bigger than the exauhst....if you cant go bigger...2 smaller will work...so long as you have more air flow in than out.......a little 5 dollar desk fan or cpu fan placed to blow and cirrculate air between the plants and light will do wonders.....

my box is the same 3x3 and 5 tall. put a intake on the bottom towards the front and a outake at the top when closeed it will make a cyclone like wind in the box and out the top exhaust mine stays drom 75 to 80 F

D port Growth said:

my box is the same 3x3 and 5 tall. put a intake on the bottom towards the front and a outake at the top when closeed it will make a cyclone like wind in the box and out the top exhaust mine stays drom 75 to 80 F

Click to expand...

What sort of lighting are you using?
Also, how far are your plants from your lighting at any given time?

250 watt MH

After some tweaking I was able to get the temp around 80-83 still with the door open. With the door closed it spikes pretty high, but that's because I still haven't drilled the passive intake. I figure I'd wait until I'm able to reach a reasonable temp with the door open. The enclosure is more like 2'x2'x5' though--the reflector just fits in there. There might be a problem with that. I'm going to post some real digital camera pics soon so it will be easier to identify the problem.

This makes me thankful I went with the air cooled 400 watt....I can put my hand 3" away from the light and it's very comfortable

I would consider putting the carbon filter in the enclosure and pulling through it. Better on your fan for sure. Even if your space is small ypu could mount it horizontally in one of the top corners of your cab, air cooled hood might be to big but a DIY cooltube could fit with room to spare, you can make one cheap, check the grow FAQ. then run duct from the filter through the cooltube and then out to your exhaust fan.
Good Luck

Alright, well here are some digital camera pictures. The last two posts have got me looking into a DIY cooltube. Tell me if you still think that's my best bet after you look at the pictures. The reason I have the ducting run behind the light and under is because the reflector is so big, if I put the ducting above, the heat doesn't really even reach it.

you should have that ehaust duct above the light.....heat rises fast and it will stay stagnate up in that corner unless you have something to pull it out......the fans you have pointed up will help with the light heat on your plant..but its the heat in the top of the box sitting there that is making it so hot....and you probably have high humidity....and yes....i agree with the last posters......a makeshift cooltube will keep the heat confined and provide good exauhst....