2 exhaust one vent

Discussion in 'Grow Room Design/Setup' started by barcodelxix, Aug 11, 2011.

  1. I want to know if you can run 2 exhaust fans from 2 diffrent boxes out one vent. The exhaust vent hole is 8 inch with a 8 inch duct to a box with a 8 inch inline fan inside it. The other box has a 6 inch inline fan with 6 inch duct. Is running the 6 inch into the 8 inch going to have air flow problems? Both fans will be on at the same time. Thanks.
  2. i dont see why not:confused:
  3. I thought there would be some kind of air flow restriction . Maby the 6 inch might have to work harder to blow into the 8 inch duct? I don't see why it wouldn't work. Guess Ill just have to rigg it up and see. Just tought someone might have done this before and could give me a heads-up if it works or not. Thanks

  4. 6inch to 8inch, shouldnt cause a problem. now if your were going from 8 to 6 that'd be a different story
  5. Both ducts have there own fan though?
  6. #6 thaSPACEkadet, Aug 12, 2011
    Last edited by a moderator: Aug 12, 2011

    I'm not any kind of engineer (except maybe a backyard engineer) but I think as long as both airflows are moivng the same direction you should be fine!!

    if your venting is like my ghetto diagram below (hope it doesnt come out all stupid) you shouldnt have problems

    8 => => => 8 => =>=> outside
  7. So the 6 inch duct will intersect with the 8 inch duct? Here's an idea of the CFM you can get through an 8" duct: Dr-Fix-It! Equivalent HVAC Duct Sizes By CFM

    Sum the CFM of both fans and see if 8" is enough for both fans to exhaust through.

    Some may disagree that you can only get 500 CFM through 8" ducting (as some 8" fans are rated up to 720 CFM) but I'd say this is a reasonable amount through 6' of duct with one 90 degree turn in it (not sure what length/turns are in your 8" duct.)
  8. #8 barcodelxix, Aug 12, 2011
    Last edited by a moderator: Aug 12, 2011
    Thank kadet. That's exactly like I want to set up. The 8 inch is 745 but I don't think Ill have it full blast, I have 2 controllers for the fan speed. I haven't got the 6 inch yet though.
  9. Simple answer. Yes

    Use a joiner or a a duct tap I think that's what its called

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