Air Scrubbing

I am in the process of building a stealthy grow room. It contains a 4'x5'x8' cloning chamber room, and a flowering 7'x7'x8' room with a vertical grow I am building in very similar to Heath's flooded tube. I am a pretty adept Carpenter and electrician and plumber, having done a lot of my own renovations myself in my houses I have had. No issues there. My question is I was thinking of running ducting from my exhaust fans into the chimney. I have a 30' tall chimney with a fireplace on the first floor (that I love during the winter), and in the basement a wood stove used to be there with a separate pipe going up the chimney. I was going to utilize this pipe to exhaust my room out. My question is with over 3 decades of built up carbon and charcoal in the pipe, will I really need to do any kind of other air scrubbing (plus it will be exhausting 30' in the air). Any thoughts?

Does it smell like fire or smoke when you have a fire going? If so, then it's going to smell like pot.

It may go up 30 feet but air currents will blow the scent somewhere. On nice calm mornings, that scent is going to settle down all around your house. Carbon Filters work. People concerned with smell should use them.

Yes, you will still smell it. I recommend a phresh filter, they've outlasted my expensive can filters and are half the price and weight.

not only will your neighborhood stink, your whole house will stink as well.

Well I can understand the smell may filter out through the air. I don't understand how the whole house would stink since every bit of it would be vented from an environment controlled and isolated room up through a sealed 30 ft pipe out of the top of the house, I am not concerned at all about the house smelling, I know it won't smell as all of the smell will be vented outside with no chance for escape inside. I was just thinking of all the natural cleaning that would occur by running through that 30 ft pipe full of carbon and charcoal. I'm not talking about running it straight into a fireplace...
I was just saying since it is running directly through a line (about 40 feet total) and about 30 feet of that pipe is chimney pipe I was wondering if it would smell terribly coming out. It would seem from the answers it would.

Regardless of placing a carbon filter in the line, which I will likely do, given some of the quick responses and it isn't that expensive, I will still be venting up through the chimney. Which is a pipe inside the chimney running all the way up, not some big chimney where it just hangs there open in my house.

Thank you for some of your quick responses.

ya know, I thought the same thing when I first started growing. I had 3000 watts and 12 plants in a completely sealed room and a carbon scrubber running full time. Then I left for a week and came back home. When I opened the front door...JESUS my house smelled like weed!

MJ oils are classified as volitile organic compounds. So much like the smell of paint or gas gets everywhere..so does the wonderful smell of good bud.

Never really been a concern until now, unfortunately. Where I used to live was much more reclusive and receptive I suppose. The room will be approximately 85 square feet, do any of you have any recommendations as to exhaust needs through that much pipe and a carbon filter. My original thought was to use 4 silent 120 mm 90 cfm fans I have already.

first thoughts are try it and report back worst case scenario add carbon filter after the fact. Typically people add the fans to the overall room before any air is pumped out

i dunno about those 90cfm fans unless your simply going to use them to ensure no backflow through the fireplace/stove

Well that's the main thought, is that it is a long pipe, and I don't want all the charcoal and such backflowing. They will have adjustable speed. I was going to use some of the same fans, because I have quite a few with a control board for intake as well, movement and flow. They are easy to place and direct and like I said, trying to use things I have. There is a sticky here about making a carbon filter I found helpful.

https://docs.google.com/leaf?id=0BzQ0JKbbMVY1YzI3ZGIwM2QtODg2Zi00OTdjLWFmYTMtMGE3OWRmNjc0NTU4&hl=en_US

diy filters are ok for small grows but i would just buy a 6-8 inch phresh filter it will last atleast 12 month and wont leave your house stinking, those fans wont be enough for your exhaust either, buy a 6 inch inline to go with your filter.

dbgrow said:

Never really been a concern until now, unfortunately. Where I used to live was much more reclusive and receptive I suppose. The room will be approximately 85 square feet, do any of you have any recommendations as to exhaust needs through that much pipe and a carbon filter. My original thought was to use 4 silent 120 mm 90 cfm fans I have already.

Click to expand...

Your kidding right? 4 120mm computer case fans? That is some funny shit. The only thing I would ever use a case fan in my grow room for is to maybe attach it to the brim of my hat to blow a cool breeze on my face.

Your going to combating a good deal of static pressure as you have to pull air through the carbon filter. And a quality, store bought filter, not something you cobbled together at home. You want to scrub all the air in the room every 2-3 minutes I believe is the standard guideline. With your room dimensions, you have 680 cubic feet of air. So your looking at around a 400 cfm fan..and that is 400 cfm WHILE pulling air through the filter.

Given your room size and distance, I would say a quality 6" fan would do the trick, combined with a suitable sized can or pfhresh filter. You talking $250 bucks or something. It sounds to me that your not growing in a medical state. If that is the case you need to step back and think some of these things through. A cheap, improvised system will work great until one day, someone smells weed, then the police (who are not stupid) , will be walking around your neighborhood at 4am, looking for that same smell..or using an infrared camera that you can buy at home depot now and start to wonder why you have a fire in your fireplace in the middle of the summer.

They will leave the scene, but they will be back. And when they knock on your door and inform you that the have a warrant to search the premises for a suspected narcotics production facility...well, lets just say that you will have plenty of time to wonder why you didn't spend that $250.

Well I was referencing using them without the filter. Originally I was asking the question about whether it would be needed since it will be vented through a dirty sooty chimney stack. Previously where I used to live it wasn't a concern, so I am not accustomed to the idea of covering smell.

That is why I was asking, so knowing that won't be sufficient I will invest in a better fan and a good filter. I'm just going to be running one 600 w hps and some t5s. On the other side of each wall is the furnace...solid ground a refrigerator, and on the floor above I have servers, I would wager my heat signature would be difficult to ascertain. I don't want to find out or get to that point regardless so that is why I asked the question. Thank you for the answers.

Right on. Sounds like you have it covered. I looked at your design again, still not certain about the case fans but heat and what not shouldnt be an issue with only 1 600. In the winter, I would probably just exhaust it into the basement and safe yourself some cash on heat. Happy growing.