Is this venting correct?

Brandon Rowland
by Brandon Rowland

Found this tucked under the insulation in my attic. It goes into a T with one arm of the T going to the vent fan in my bathroom and the other arm going to other places... Is this right?

q is this venting correct
  4 answers
  • Should be vented to the outside, not into the attic. Where do the other places lead to? Cheryl provided an excellent link.

  • Bijous Bijous on Jan 13, 2019

    Hi. How many outside vents do you have for your bathrooms? If this bathroom backs up to another, it's possible the tubes hook to a common vent. If you're concerned the exhausts are not set up correctly, do have a plumber take a look.

    • See 1 previous
    • Bijous Bijous on Jan 14, 2019

      If this are connected to the exhaust vent and not the heating/cooling, a plumber is who does the exhaust work. An HVAC professional only does heating/cooling.

  • Seth Seth on Jan 14, 2019


    From what I see and what you described, something is not right. First, the duct you are holding for your exhaust fan should never be connected to a wet vent (the vent stack that serves your toilets, sinks, showers). And, most plumbing codes do not allow for multiple bathroom/kitchen exhausts fans to be connected together unless installed with a supplementary in-line fan. If you could post a couple more pictures of the T you mentioned it would be easier to see what the issue is. Basically, each exhaust fan should be vented directly through the roof, using rigid duct, not the stuff you are holding. It looks like you have 4 inch ducts that are not insulated. Your exhaust fan can probably be outfitted with either 4 or 6 inch ducts. The 6 inch will be more efficient and you should insulate all duct work in an attic space. That does not mean burying it in the loose fill insulation i see in the picture.