So I’m finally dialed in but I’ve got a concern with my exhaust. I have a floor in the joists in the basement ceiling that is placed between two studs in the above room encompassed by drywall sheets on both sides. This runs up to the attic where it exhausts. I was not able to run a piece of ducting through this void space as there’s electrical wire that runs through and I couldn’t pass even a 4” round duct by it. Any thoughts. I’m concerned moist warm air will quickly wick into my drywall sheets and I’ll see damage in the rooms above. Thoughts?
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You’re right to be concerned, don’t do it.
Unless it’s a rental and you really don’t care at all, cause that’ll wreck your shut up. But yeah, don’t do it.
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upon thinking about it, is there room to run an equivalent to a 4" round duct by the wire? i used to be a carpenter and built a lot of houses and modified several grow areas. 4" round vent is 12.56 sq in, so a rectangular piece of duct that is 8in x 1 3/4in gives you 14 sq in. if you go 1in x 14in you get the same amount of air moving if you can’t get the 1 3/4in duct by the wire. you should be able to run the rectangular duct behind the wire and slide it up to the top plate of the wall but you’ll have to make a connector so you can hook the round vent to the rectangle vent. if you get a roll of thin flashing and some duct tape it isn’t that hard to make ducts but wear gloves because it’s like making little razor blades.
the problems you’ll run into are getting access to enough room to run everything without making too much of a mess and getting the vent through the top plate of the wall into the attic, otherwise you have just made a huge effort to move the moist air from the bottom of the wall to the top and it will still damage the drywall. if it’s your house and not a rental, you can run the round vent up the wall on the inside of the room and cut a vent hole in the drywall in the ceiling and run it that way much easier but it doesn’t look as good. if you do that, go up and make sure to cut the hole from the top down so you don’t cut anything you can’t see. poke a drill bit up in the spot you are going into so you can locate it from up top. if you go this route, come about two inches away from the wall to make the hole into the ceiling to get around the drywall nailer on the other side of the ceiling. if that won’t work, take some pics and post them. good luck with it.
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Mold. Guaranteed. Stop. Now.
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I work in the home repair industry. Doing this will create mold between your walls. Venting into your attic can also cause mold but this is less likely in the attic. Venting into your attic is still a bad idea though, unless you’re venting through an actual roof vent, if you live in an area that gets snow. Venting hot air into your attic will cause ice dams which will cause damage to your roof and interior water damage. 
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not to mention the melted snow while all the other houses are covered in it, makes it pretty obvious what you’re up to. the obvious fix for that is to run it into the plumbing vents which is fairly easy as well. that helps hide the smell, but you’ll still get wafts of it sometimes. a friend had a vent into his attic once with a ozone generator for the smell, but be careful with those as they can be bad news if you have them venting into the space you live in i’ve heard. it never did cause any issues with ice dams, but those are also easily preventable with little attachments you can put above the eaves of your house.
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Oh yes, this is exactly what happed to me, when I exhausted into our attic. It was the best extracting system I ever built.
Found a sweet spot, from basement, up into a bedroom closet corner, then right into attic.
I used a plenum kits for Lowes, installed a Vortex fan, insulated it, and quickly forgot about it as it worked a treat!!
Winter comes along, a big snow fell, I go out to shovel my driveway. It takes like a hour and half, and out by the driveway, as I’m clearing out the mail box area, when I see a car driver, looking past me, and up a bit, like a bird watcher would.
I take a few scoops, and just as I’m done, another car, with the driver looking past me?
WTF is going on…well as I turn around, there is a hole, melted down to the BLACK SHINGLED roof, about 3 feet around, right smack in the middle of the roof sloping towards us!
Blind panic, and that thick metal taste, oh fuck I’ve done it now!
I run down, shut it down, and open the attic door to flood heat upstairs, in a few hours, the hole was gone…so was the cool through the floor exhaust system.
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Other option is venting from my room the tents are in (not sealed just a basement spare room) and venting it across the basement 40 feet to another room……?
One of you mentioned plumbing? Like my hot water tank exhaust? My hvac exhaust? I hate to do those as they are off the house by a sidewalk.
The attic is a huge space, the venting just went thru the floor and half way between roof and floor . We do get so here. However I figured 70-80* air being vented into a 30* attic with 2500sqft of void space would dissipate enough to not melt a hole directly above it
I was going to ask if they could safely drill a hole and sawsall a hole large enough without hitting wirers. even smaller on each side if wire is in the middle…
Confused, my wires are half way up the wall. I have an entrance to the wall void and an exit in the attic. I’m leaning against this though as I get snow. What about the idea of just exhausting into another room about 30 feet away from where my tents are in? Will that push that hot humid air far enough out? I figure if I scrub it, it’s just dumping clean air back into the house on the other side?
i would use a hand saw, they make a drywall saw that looks like a big bowie knife. and do it from the top so you can see what you don’t want to cut.
yeah, @Animosity the pvc exhaust vents. they go up through the attic and are for sewer gas venting and letting the air not build up a vacuum and the plumbing stops working. you can splice into them with a ‘t’. just make sure you glue it good when you put it back or you get sewer gas leaking into the attic. shouldn’t hurt anything but it is heavier than o2 and can sink into the living area and smell bad. dumpiing air into the living area is also acceptable, it doesn’t hurt anything at all, you just have to watch the humidity in the environment as a whole. i made a carbon filter out of a couple of pieces of pvc, some window screen, and an air filter. it worked pretty well. if you’re ok with that it’s a lot easier than going through the attic.
I don’t have a bathroom in the basement with one of those pipes to tie into. The only pvc in the basement is the drain from the toilets above. I’ll vent it across the basement instead. My thought is that the humidity will dump into the empty 15x15 room with workout equipment and just dissipate out. Worse case I end up dropping a dehumidifier in that room. I’d assume if my scrubber is effectively working then I should have nothing to worry about as far as smell. It shouldn’t be much different then if I vented the scrubber through the attic I presume? Would I be better to run a scrubber in both the veg tent / flower and the grow room itself as a whole or is that overkill?
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As previously mentioned, a REALLY bad idea to exhaust (any where) within your house.
What’s the point of the venting? If it’s not heat related, better to just run a dehumidifier then exhaust into another room.
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My space has no access to outside without doing major construction. Its basically underground, basement like.
Its far from ideal and will likely drive up your operating costs, but I make it work by exhausting into the lung room for my tent. The room is about 10x20. That room just has passive air exchange with the rest of the basement/house.
I’ll also go out on a limb and suggest the majority of home growers are probably exhausting within their lung room. If it’s a small tent and you aren’t exhausting into a confined small place with temp extremes, there’s not a lot of mold danger
Heat/humidity are obviously going to be your potential issues, but they can be managed if you must. Good luck
Heat was a concern. Two 600w Photontek. One in a 5x5 and one 4x4 in a 14x 9 foot area. Rather than dump the scrubbed air back into the lung room the tents are in I figured why not take the little effort and move it 40 feet to another room to help w temp as well….
Your still scrubbing that air that your dumping back in right?
A real good carbon filter, yeah.
Yeah, that’s a fair amount of plant density in a smaller lung room.
Hopefully you have lower ambient temps in the lung room so primarily a humidity issue. But if not, with that plant count, it may be hard to control without venting outside.
going through the wall into another room is a fix. i don’t think it would hurt just going across the room though. i’d do the one with the least amount of work and test it, then be prepared to do it again if the next one doesn’t work.
Outside house or to another room 40ft away?