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Community and Q&A

Air return: bathrooms and walk-in closets

BJHuffine | Posted in General Questions on

As is evident from a previous question, I’m working through the details of our upcoming plans to prepare for new construction and I’m hoping to do this right.  This question arose due to my curiosity.  I read a Lstiburek article on placing air handlers that are in the garage in closets with ventilation (jump ducts or transfer grilles) and a return.  In his article, he mentioned closets in general need jump ducts to equalize pressure.  Hmmm… so I started looking for more information on GBA and finding two really good articles on bedrooms needing the additional returns with jump ducts (or transfer grilles) to the hallway.  This is a little different use from the “mechanical room” idea (since it only involves duct/grille for return and not supply and return), but makes total sense and something I think most people experience.

1.)  However, these articles address that first level room.  What about second level rooms like a master bathroom and walk-in closet?  I would suppose one wouldn’t want to clutter the hallway ceiling with dedicated returns to each of those?  I’m sure also that there would be some creativity with the HVAC contractor, like putting a return in the master bedroom, but if we negate that (especially if space doesn’t allow or folks are in an existing house), then how would that be handled?  Would the hall grille be connected in the attic with a Y-connector of some kind?  Would the secondary returns be connected to the bedroom return in some similar way with a single trunk line back to the hallway?  Or “chained” in the sense that the secondary room is “jumped” to the bedroom and then the bedroom “jumped” to the hallway with a larger duct to accommodate both rooms?

2.)  And in thinking about master bathrooms, I got to thinking of bathrooms in general.  How should they be returning air?  Same way I assume, or would there be a concern that moisture would enter the system and if it did, is that a bad thing?

3.)  And in thinking about bathrooms (yes I have ADD and this was a squirrel moment), I got to wondering how you should exhaust bathroom moisture to begin with?  My current home’s vent duct goes through the attic to the soffit.  But that puts another dreaded hole in the ceiling and in the bathroom of all places.  Is that a problem?  Would there, or should there, be a better way?  Or is there a way to seal over the bathroom vent to prevent moisture from accumulating in all the wrong places?

I can separate questions in different posts if necessary, just let me know.

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  1. GBA Editor
    Martin Holladay | | #1

    Whether or not a bathroom or a walk-in closet needs a supply register depends on whether the room has an exterior wall. If the room has an exterior wall, a supply register makes sense. For these rooms, the return is usually handled by undercutting the door.

    1. BJHuffine | | #2

      Thanks for your responsiveness Martin. I guess I was over thinking this a bit then. Yes, in my new home the master bath (16x10) does have exterior walls and will likely have a supply. The walk-in closet (9x10 and accessible through the master bath) will not. So then I assume I would size the jump duct for all three from the master bedroom to the hallway.

      What are your thoughts on the best approach to venting bathrooms?

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