Lighting, Light Fixtures, Ceiling and Exhaust Fans - Can I use one roof vent for two extractor fans?
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lisarobb
11-01-07, 09:36 AM
We have two bathrooms, back-to-back. One has a ceiling-vented extractor fan, one has a tiny window. Mold keeps appearing in the second bathroom. I would like to install an extractor fan in the second bathroom, but I'm trying to avoid having to cut a second hole in the roof. Since the ductwork for the existing extractor fan is quite close to where I will be installing the second fan, would it be okay to attach the new duct into the existing duct and let them share the same roof vent?
cwbuff
11-01-07, 11:06 AM
I think you would have to come up with a way to isolate the two vent paths. Otherwise you might just vent from one bath to the other depending on how the ducting is configured.
John Nelson
11-01-07, 01:50 PM
You might be able to control the air flow with one-way baffles. But you still might have a noise problem in that the pipe will serve as an audio conduit between the two bathrooms.
I'm guessing that you've never cut a hole in your roof before. It's really scary the first time you do it, but after that, you realize that it's no big deal. In fact, it's pretty trivial.
Or maybe you could route the vent out the eaves.
They do make multiple-bath vents, with one fan in the attic. These units probably already have all the air-flow controls, and maybe some noise baffles. Some rewiring would be required to use this setup, however, since you want the fan controlled from both rooms.
I'm guessing that you've never cut a hole in your roof before. It's really scary the first time you do it, but after that, you realize that it's no big deal. In fact, it's pretty trivial.
Or maybe you could route the vent out the eaves.
They do make multiple-bath vents, with one fan in the attic. These units probably already have all the air-flow controls, and maybe some noise baffles. Some rewiring would be required to use this setup, however, since you want the fan controlled from both rooms.
lisarobb
03-10-09, 10:40 AM
End result: We chickened out and just put in a second conventional extractor fan in the second bathroom. We paid an electrician to do the wiring ($130 -- does that sound reasonable?) and put in the fan ourselves. Rather than cute a second hold in the roof to vent the second fan, we used flexible tubing and angled it over to go out the same hole as the existing fan. The existing fan in the main bathroom vents straight up to a hole in the roof covered by a metal vent cover. The vent cover was quite a bit bigger than the vent pipe, so we widened the hole in the roof enough to fit vent tubing for the second fan.
It is all working nicely. We liked the quietness of the next fan so much that we swapped out the old, rattley fan with a new one too.
It is all working nicely. We liked the quietness of the next fan so much that we swapped out the old, rattley fan with a new one too.
Gunguy45
03-10-09, 11:22 AM
The charge sounds pretty reasonable. And your venting should work fine.
When I moved in here they had 2 bath fans and the dryer all vented to one big (like 8") T-shaped vent on the roof. The ducting was all flex aluminum and beat up, so I redid all of them to individual vents, but it had been that way for years and worked fine. The HVAC place said thats how most were done around here in the '90's.
When I moved in here they had 2 bath fans and the dryer all vented to one big (like 8") T-shaped vent on the roof. The ducting was all flex aluminum and beat up, so I redid all of them to individual vents, but it had been that way for years and worked fine. The HVAC place said thats how most were done around here in the '90's.