Ventilation question...

Hi all. Old smoker, new grower, first-time poster. I built a DWC NGB-style cab several months ago from info on forums like this one. So thanks to all who contributed. And if you're reading this, you probably contributed.

Like most in cabs, my biggest concern has been heat buildup. I have a DIY cooltube that exhausts the veg compartment. Air is pulled from the bottom of the cab through an 8" darkroom louver. The cooltube exhaust is (over)powered by neg pressure from a squirrel cage fan (180 CFM) in the utility partition of the cab. As is, I can touch the tube without discomfort but the cab's temps have reached the low nineties on occasion.

My question is, finally, will drilling a hole directly between the veg chamber and utility area help vent some of that heat? That fan should be big enough to pull through the cooltube and straight from the cab also, right? Will that even make a difference since the cab's air is being pulled through the open end of the tube anyway? I just wanted to get some expert advice before I go drilling holes all willy-nilly like. Thanks!

anyone want a bump?

the fan should change air 2-3x/min curves long ducts and obstcles diminish venting,there must be hole big enough for free passive air intake. goin vertical or gettin reflector?

I would put a fan on the intake, no need to drill a hole yet, just get some pressure on the intake and it will make huge differences (assuming your intake air is cooler than the room) i try to keep my intake air 65-68 degrees. Also fans in the room help to get the heat out also, pretty hard to have too many. And i think that zem was refering to your cool tube that doesn't have a reflector, you should probably get/build one, or hang the light vertical.

the fan changes air more than 2-3x per min. there's enough suction through the cool tube with filter on fan to hold up a sheet of paper no problem. so, the extra hole may not help but it shouldn't hurt anything is what i'm thinking.

and i don't have a reflector yet. i put aluminum tape on the roof for now (mylar was a bitch for me to work with). the little 250 is more than adequate for the small space (2x2x3), so I'm not in a hurry to add one. sans the reflector also gives me more vert space.

and a vertical grow may be in the distant future...

thanks for the input zem

good point, Trueno...i actually went and got a portable air conditioner for the room it's in...that helped a lot...maybe i will hold off on the hole...the air flow seems good, so the hole probably won't help...and i'll add another of those zippi fans...

by the way, that is an awesome tree avatar...yours?

Yeah thats mine, one of the smaller ones last harvest, but my favorite plant. White Rhino, vegged 1 month flowered 8 weeks. Wasn't huge yielder, 3 ozs cured. I swear it started to flower the day i turned to 12/12.
Anyhow, it sounds like at this point you are using another room to intake and exhaust from/to? If so i would try to lower the temp in that room, or intake (or exhaust) from another room/area. I personally intake from another room and exhaust straight outside. This way i control (until the middle of summer) the intake temp, and get rid of all stale, hot air. Probably raises my heating bill but makes dialing everything in much easier.

very nice...
thanks for the input...unfortunately i'm renting right now, so intake/exhaust is same room...i think exhausting to outside would be ideal...i will try to rig a way to do that without breaking the lease agreement...thanks again

JimBro said:

very nice...
thanks for the input...unfortunately i'm renting right now, so intake/exhaust is same room...i think exhausting to outside would be ideal...i will try to rig a way to do that without breaking the lease agreement...thanks again

Click to expand...

I feel you bro i am renting and trying to get a setup going myself so it does suck. Esp if your trying to do hydro. So many variables.

JimBro said:

very nice...
thanks for the input...unfortunately i'm renting right now, so intake/exhaust is same room...i think exhausting to outside would be ideal...i will try to rig a way to do that without breaking the lease agreement...thanks again

Click to expand...

your basically circulating the same air. you need to exhaust out

sm0ker, where there's a will there's a way...I'm lucky in that the landlord has never come around in the years I have lived here...not sure of your situation, but i've rented apartments before where the management would come into the apartment and not even leave a note saying they had been there or what they had done, so you gotta be extra careful...lock your shit up and put a 'film developing - do not open' sign on the grow door or something...

you're right, zem...the room with the box is only 10x10 or so and I have to leave the door shut most the time...the portable ac i have has an exhaust only feature that exits through the window...i'll just run that and will, in a very roundabout way, achieve the same effect as exhausting directly outside from the box...