Dual bath fans for shower/commode area?

ontariomomJanuary 13, 2013

Hi all and thanks in advance for any thoughts. I have cross posted this in the bathroom forum as I was unsure what was the best forum for these questions.


I have read about dual fans that allow you to have a fan positioned in two parts of your bathroom, but the two fans vent out one opening in the roof (or wall). We wondered about this kind of set-up in our ensuite with one fan located near the shower, and the other in the toilet room. However the HVAC contractor discouraged us as he felt the makers of these dual fans offered much noisier fans than going with say separate Panasonic Whisper fans with one in each part of the bathroom. His solution would of course lead to two openings in the house.


1)Can anyone recommend a quiet, effective dual fan bath fan that combines fans in two areas into one opening? Is the dual fan by Fantech any good (I see that other posters on the bathroom forum have recommended Fantech brand for their single fans)?

2)If you do recommend these dual fans, can I also effectively combine a dual fan for two adjacent baths in our down stairs (back to back baths).

3)What do you think of the Panasonic Whisper Value fan (model FV-08VS1)? These are the Panasonic fans that the HVAC contractor installs in new homes, but I wondered if I should be looking more closely at the higher end Panasonic fans, which the contractor can certainly order in for us. For what it is worth we will also have an HRV running to each bath, so the fans are simply to do a quick job of removing moisture in the bath, defogging the mirror. The fans are not the only method of ventilating the baths.

4)Also, what do you think is a reasonable cost to buy and install each bath fan? We have been quoted $250 per fan (based on the basic value Panasonic fan around $79.00 retail from Amazon). Some of the fans we need will vent out the roof, others out walls (a few with rather long runs to an outside wall).

Any thoughts on any of these questions would be very appreciated!


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Why can't you hook up ANY two fans to a single vent? Why does it have to be what you call a "dual fan"?
All of our vents were installed in the soffit... nothing pokes through the roof.

    Bookmark   January 15, 2013 at 7:54AM
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"Why can't you hook up ANY two fans to a single vent?"

One potential problem might exist when only one of the fans is operating with back flow through the idle fan.

Additionally, I would assume that the duct size would have to accommodate both fans operating simultaneously.

    Bookmark   January 15, 2013 at 8:21AM
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I have Panasonic bathroom fans. I am not familiar with the Fantech models.

I have attached a link to the dual Fantech fan. It is one fan connected to two input grilles. This set up should be quiet since the fan motor is installed in the attic. You could set this up with two adjacent bathrooms.

The Panasonic fans are supposed to be the quietest. Panasonic does not offer a dual fan set up. You would need to have two fans and two separate exhausts.

The installation price you were quoted seems reasonable.

I would recommend separate Panasonic fans controlled by electronic timers. The exhaust vent in the attic should be insulated in order to prevent condensation.

Here is a link that might be useful: Fantech dual fan

    Bookmark   January 15, 2013 at 9:44AM
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Thank you everyone for your replies and helpful tips. I am going to see if I can find an HVAC company that has installed these dual fans. If just seems to make sense to reduce the number of openings through walls or roof that we will need.

Ncrealestateguy, we already have bathroom roof vents installed for these future fans. This was done at the roofing stage, so too late to re-route the vents out the side walls for two of our baths. I hope this is not going to be a problem.

Mike, you mentioned you have Panasonic fans. Do you recall which model you have? Given you recommended electronic timers, I am assuming your fan is not the Panasonic Whisper Value model the HVAC company was suggesting.

Thanks again.


    Bookmark   January 17, 2013 at 11:20PM
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I put in a Fantech with a single line last year. It's very quiet because the motor is at some distance from the opening, exactly as mike describes. The sound is mostly of air movement like a soft whoosh, there's almost no motor noise at all.

When installing a dual connection, the two branches of the V need to be the same length to have the same draw. That doesn't mean the motor needs to be equidistant from the two ceiling grills, you just make the two legs the same length. Also, it's recommended for any brand of a humid air exhaust system to use a timer to allow additional run time to clear moisture. When using two runs to different bathrooms, it can easily be wired so that a timer in either bathroom turns the fan on.

The Panasonics could be equally quiet, I'm not familiar with them.

I scratch my head when I hear of a contractor giving a baloney answer. I can't guess which of the possibilities fit the situation (he had extra Panasonics on hand, or he gets a better margin on Panasonic, or he doesn't carry Fantech, or he'd never done it before, or ?) but I try to avoid people like that.

More info on the Fantech site. I found their call-in tech support excellent, they answered all my questions and then directed me to an internet seller they said they had the best reports from. It arrived in a few days and my HVAC contractor was more than happy to simply install what I'd bought.

Here is a link that might be useful: From Fantech site

    Bookmark   January 18, 2013 at 1:22AM
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I think my Panasonic fans are one model generation older than what is currently available. I have the equivalent of the FV-15Q5 and the FV-15QL5. The latter model has a built in light.

The electronic timer replaces the wall switch. It does not come as part of the fan. I like the electronic version rather the the rotary mechanical type. Either one would work. You can use the timer on any fan.

    Bookmark   January 18, 2013 at 7:39AM
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This is sooo easy - those fans in the ceiling with lights are just crap.

Google Soler & Palau for some good in-line fans.

Basically, you mount the fan in the attic (or ceiling) and attach both ducts to the inlet of the fan. They have inexpensive plastic dampers so the air only goes one way.

Your contractor appears to be a know-nothing.

    Bookmark   January 18, 2013 at 10:58AM
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Hi Snidely, Mike and Doug,

Your collective wisdom and info is very helpful, and I am grateful for your responses. I assume the HVAC contractor has not used the Fantech fans before, and may have a bad experience with another sort of dual fan (or else he had some Value Panasonics in stock LOL as suggested by Snidely).


    Bookmark   January 18, 2013 at 10:46PM
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What is so bad about the cieling fans with lights? Besides that since the motor is inside the bathroom, are loud.

    Bookmark   January 19, 2013 at 7:55PM
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Panasonic bath fans are very quiet. I have installed at least 4 of them in houses I have owned or own.
Venting bath fans out the soffitt is not the best thing for your attic. The purpose of attic ventilation is to get the moist air out. Venting a bath fan out a soffitt just sends the air right up into the attic. Lots of general contractors do it but not smart ones.
I know of a house where 2 baths were vented with one fan and apparently every noise from one bath was heard in the other. Can't verify that but a trades person told me about it.

    Bookmark   January 20, 2013 at 11:25AM
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The exhaust fans I have seen vented out the soffit have been solid ducted from the bathroom ceiling to the exhaust duct outlet on the underside of the soffit - no air exhausted into the attic.

When I redid my Master Bath last year I opted for a slightly longer duct run to exit at the vertical gable end.

    Bookmark   January 20, 2013 at 12:06PM
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Yes, that is correct. My soffit vented fans are piped from the fan all the way to the soffits to the outside. No air goes into he attic.

    Bookmark   January 21, 2013 at 8:15AM
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One question about the Panasonics, can you get replacement parts easily? Broan/Nutone offer replacement motors/bases that you can get just about anywhere.

I'm not sure whether the two fan/one vent thing would be worth the hassle, if it wasn't done right you could have problems.

As for soffit vents, OP is in Canada. Soffit vents for bathroom fans haven't been permitted in British Columbia for years, and Canada's working towards a unified code so I doubt they're allowed in Ontario, either.

    Bookmark   January 23, 2013 at 2:11AM
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Thanks for the heads up, Alan on the code regarding soffit vents. Once we are done our addition we will have two small baths on the main floor which the contractor had talked about venting out the side of the house through the gable. I will check to make sure Ontario allows side of home venting for a bath fan. If we do go for the Fantech dual fans I will ensure the contractor has installed this product before, and is not learning on our job. I appreciate your input.


    Bookmark   January 23, 2013 at 6:50PM
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Nutone has an entry level/builders' grade reputation. Panasonic and Fantech (to a greater extent) seem to be considered as having better quality.

Does that matter? Yes to some, no to others. Replacement parts are easily available for any major brand and, don't forget, are unlikely to be needed anytime soon.

    Bookmark   January 23, 2013 at 8:06PM
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