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multiple bathroom exhaust fans into one vent??

22707 Views 9 Replies 2 Participants Last post by  JulesB
Back to working on my bathroom venting issues. Would like to run three seperate bathroom exhaust fans into one vent pipe exiting out an attic gable wall.

Longest run (50cfm) would be approx. 16' with one 90 and two 45's. Second (70 cfm) would be 13' with the two 45's and the closest (50cfm) would be 4' with one 90. (the 16 hooking into the 13 at approx. 12, both hooking into the 4 at 3, if that makes any sense)

Questions (numerous):

-can I even do this? possible restrictions? local code issues?
-size of pipe runs?
-how to T or Y into the run? special duct pieces?
-special backflow dampners?
-three seperate fans, or use one (variable speed?) near the exit?
-referals to companies who make such a setup?/special parts

I'd prefer just one fan at the exit, for several reasons. Quieter (hopefully). Easier to get centering location in each of the rooms, and can use custom vent covers. (I can build duct boxing myself).

Any and all help/references greatly appreciated.

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I would go with a single unit like that is used in commercial structures. One fan pulls for all spaces needing venting. Better than putting in multiple units, plus will be quieter.
It depends on how many baths or spaces that you are controlling. Broan, Panasonic, and a few others have them. Basically the motor unit sits in the attic, and pulls the air through the ducts from each space. As for turning the fan on, you could set it for when the light goes on (ie relay), or through a ir spot that would tell if someone enters or exits the space.
That would work for the zones. This is what you need to get They come in 2 to 5 room setups. I know that they are expensive, but when you factor in the costs for separate units, it justify spending that. I would go for it if I had two baths in my house, especially when you do not want to hear the fan running when someone uses it.
You would have to check out the spec's. Best thing is to get in touch with an environmental engineer that can take the blueprints of the home, or come in to get the numbers to do the calculations for the best option. It would be money worth spent, than trying to figure on your own and end up with the wrong equipment that is either undersized or oversized.
1 - 4 of 10 Posts
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