Exhausting into existing a/c?

Discussion in 'Grow Room Design/Setup' started by hountzz, Nov 15, 2014.

  1. Looking to put an exhaust fan and carbon filter in my room....
    Can I tie my exhaust directly into the central a/c unit?  Don't want to drill exhaust out of the house...

  2. As long as it's the outlet, why not? Sounds like a good solution to me, a vent is a stealthy way of getting air out of the room. Far better than sticking a hose out of the window. I do something similar but it's a passive vent not a/c...
    IMG_9178 (640x427).jpg
  3. I agree.  As long as you are using the exhaust ventilation, and properly insert a port;  You should be good.
    The reason this was an easy answer is because you have the fan, and the "carbon filter"!
  4. #4 hountzz, Nov 16, 2014
    Last edited by a moderator: Nov 16, 2014
    thank you both!
    here is the exisiting a/c duct that I'm thinking of tying into.
    Where it goes into the ceiling, is actually where the vent goes into my bedroom, so I don't think its a return air duct....

    Attached Files:

  5. Should work, just get a t piece...
  6. hountzz...good thinking (coming from someone formerly licensed in HVAC).

    Only thing you need to remember is to set it up so there's no backpressure...fans for grows are MUCH higher CFM than your home heating/AC system, so it's FAR too easy to create overpressure that blows back through the system, which will damage the AC and furnace units AND prevent them from keeping the house comfortable AND make the whole house get coated in the carbon dust inevitably drawn out of the filter (not to mention that dust hits the furnace, or gets near a spark, it can burn explosively...kind of like lighting a match in an empty grain silo, or dropping a bag of flour near a lit stove...the fine particulate WILL go BOOM). So on top of the T joint, I'd consider adding a backflow prevention unit...unless you want to join them right next to the outlet itself, so it's too close to the "exit" to create overpressure all the way back through the system.

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