In-Line Fan (4") to serve multiple bathrooms?

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sw_ross

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Is it possible to use an in-line exhaust fan to serve multiple (3) intakes (if that's a proper term?)?

I have a challenging situation with log walls and open truss vaulted ceiling area with limited ability to vent out the bathrooms.

This is a remodel. The master bath needs 2 exhaust locations (commode and main area/shower) and another for a half bath.

There is already a 4" hole from the previous bathroom venting. The GC (and myself) are wondering if we can use the one existing hole to vent the 3 locations?

I was thinking about putting an in-line exhaust fan near the port through the log and the have 4" duct going to each location (maybe using wye's).

I've used the in-line fans for only one location, not more.

Thanks
 
I think as long as the fan is rated for multiple connections or has the ability to move the total CFMs of the combined areas, it would work.
 
I agree with Bill there are fans designed for this. A good thing about them is that since they're remote from the bathroom there almost completely silent.
 
infinity said:
I agree with Bill there are fans designed for this. A good thing about them is that since they're remote from the bathroom there almost completely silent.
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Aesthetically, that would be my biggest concern. Operationally, finding a fan with enough oomph is the top thing, and then there is the mechanical code to consider; does it allow multiple spaces to be exhausted by one fan? Last thing, you'll need balancing dampers to control the flow, otherwise the farthest inlet may get very little flow. And balancing dampers can cause noise.
 
The Panasonic fans use adjustable grills to balance the air flow. A common complaint about these fans is that they're so quiet you don't know if it's actually running.

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I have one of these Panasonic fans, and they are very quiet. Well, as long as it's sized correctly. They can move a lot of air, which can give you wind noise at the grate if you're not careful.
 
infinity said:
The Panasonic fans use adjustable grills to balance the air flow. A common complaint about these fans is that they're so quiet you don't know if it's actually running.

na.panasonic.com

Create Today, Enrich Tomorrow

At Panasonic, we’re working to change the way we power our homes, our travel, our businesses - and our lives.
na.panasonic.com na.panasonic.com
silver-panasonic-bath-fans-fv-40nlf1-64_1000.jpg
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Oh, don’t worry about the noise. Bucking it down to 4” round will take care of that ;)

By the time you move enough air to exhaust three bathrooms through a 4” anything you will sound like a jet engine ready to takeoff, you won’t have sufficient capability in the fan to overcome the static pressure required to move its design CFM so you will only be getting a fraction of the air movement that you think you are at that increased noise level

Time to call the sheet metal guy to size the run properly and to tell you how much CFM you need for each room. You should cut a new hole to outside. The person that has to live with it will thank you later for not sticking them with a garbage install.


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I agree that there is no hope of properly venting three bathrooms through an existing 4" hole.
 
Thanks for the info!
I'll email the HVAC guy and ask him about doing the install, then I just have to wire it up!

The HO is already wanting the spiral ducts for supplies since it'll be exposed.
 
sw_ross said:
I'll email the HVAC guy and ask him about doing the install, then I just have to wire it up!

The HO is already wanting the spiral ducts for supplies since it'll be exposed.
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That's what I'd do, too. The same materials and workmanship should be used for all visible ducting.
 
LarryFine said:
That's what I'd do, too. The same materials and workmanship should be used for all visible ducting.
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Wow, that's going to drive up the sone rating a tad. Add a couple more outlets and tell the customer he's getting a pipe organ. Exposed metal ductwork connected to vibrating equipment. You'll wake up the whole state if you take late night showers.
 
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