Replies

1. 
   razzman | Feb 26, 2006 09:33pm | #1

   Greetings n,

   This post, in response to your question, will bump the thread through the 'recent discussion' listing again.

   Perhaps it will catch someones attention that can help you with advice.

   Cheers

   'Nemo me impune lacesset'
   No one will provoke me with impunity

1. 
   norsky | Feb 26, 2006 09:51pm | #2

   Many thanks, Razzman.

   Norsky

1. 
   razzman | Feb 26, 2006 09:55pm | #3

   yeah, well, we'll see. ROAR! :o)

    

     

    

   'Nemo me impune lacesset'No one will provoke me with impunity

2. 
   BillHartmann | Feb 26, 2006 10:48pm | #4

   I am not sure if what you want to do will work. If you both fans will need an flapper to get keep one one from back feeding into the other one.But I know that there are remote blower units that can be located to draw out of two different rooms.Fantec is one brand.

2. 
   sully13 | Feb 26, 2006 11:29pm | #5

   I agree with Bill that you would need some sort of a flap gate on each vent line before they intersect to prevent back flow.  I read recently that some local muni's are not allowing exhaust ducting to be tied together for some reason or another.  Maybe to prevent back flow. 

   I need to go back and read the article.  Of course it depends where you are located.  Are you able to run the two ducts through the wall in adjacent joist bays?  If yo are remodeling the basement bath now would be the time to accomodate the first floor exhaust fan.  That would be preferable to going north and punching through the roof.

   sully

3. 
   basswood | Feb 26, 2006 11:52pm | #6

   This company sells what you want...a single fan and vent penetration that serves multiple rooms.

   http://www.hvacquick.com/hqthconfig.php?fm=BPKG&ID=5ec0mqhio70mtb560uklroid40

   I have not used their products, but it sounds cool. Ad on page 168 of the 25th anniv. issue of FH

4. 
   user-86517 | Feb 27, 2006 08:11am | #7

   I think it would work to put two fans onto one duct. (But I've never done it). Bill is right, you do need a flap gate, an additional flap gate (fans come with them, they hook onto the fan box and then you attach the ducting). I think if you installed two additional gates as close to the intersecion of the two ducts as possible, you would still have plenty of suction, even if both fans were running at the same time.

   As a side note, I now use PVC pipe as the exhaust fan ducting rather than galvanized or aluminium. There are several reasons why:

   1) Workability (Unless your an HVAC guy accustomed to working with metal ducting and like small cuts, PVC is very simple and straitforward to use. The final product looks cleaner and better than metal).

   2) Sturdiness (This stuff is extremely solid, and solvent at the joints makes it air tight).

   3) Cost (It actually costs less than metal)!

   4) Noise (Because of it's thicker wall,smooth interior, and less seams, it is a lot more quiet than metal).

   5) Long Runs (No need to join a bunch of short sections, this stuff comes in 10 foot lengths. Also you can shove a long section through a cavity, to a corner of an attic, etc..., something just not possible with metal).

   6) Efficiency (Much better airflow because there is no possibility of denting it, less seams, and no chance of seperation or leakage over time).

   Now I don't know what the code is for this, but I actually don't care. I am that convinced of its superiority over metal ducting. (Of course if someone points a major danger to using PVC I will reconsider and humbly beg for forgiveness). It is basically bulletproof. You won't be sorry you used it.

   --Andy

1. 
   DanH | Feb 27, 2006 02:26pm | #9

   In commercial situations the flammability of PVC could be an issue, but not for home installs. And there is a listed nonflammable plastic duct available (though I don't know if it's available in smaller sized).
   If ignorance is bliss why aren't more people

   happy?

5. 
   xxPaulCPxx | Feb 27, 2006 09:54am | #8

   If the bathrooms are both small size, you can use one big fan to draw air though both outlets at the same time.  Instead of the fan being in the ceiling, it is located just after a Y connection that joins the exaust of bathrooms.  The fan switch is wired just like a 3 way light switch, so both rooms can turn it on and off.  If it is too quiet, you can add a small light to it so you know you have activated the fan.  I was able to get a fairly cheap axial bathroom fan at HD that connected easily to 8" HVAC duct.

   Be sure the ductwork is insulated, so that the moist air doesn't condense on the sides.

   Rebuilding my home in Cypress, CA

   Also a CRX fanatic!