Replies

1. 
   calvin | Aug 14, 2012 07:42am | #1

   user.....

   Depends on a couple things-your climate, ease of run, maybe-power of fan.

   Here we can get quick condensation on an uninsulated pipe that will drain down or lay in a pipe if there's no fall (to the gable locations) for it to maybe drain out.

   You can run up to a roof vent if you provide a flat for the water to come back down and not drain into the fan/ceiling area.

   But, the key in a moderate condensing situation is to keep the fan running after "clearing" the room of steam and moisture.  For  this, use a timer switch.  I like the button pushing type from Lutron-you can get 5,10,15 min or even better-the 15, 30, .........

1. 
   davidmeiland | Aug 16, 2012 12:30am | #2

   110 cfm

   is a pretty big fan. How big is the room? Maybe you can afford to lose some airflow and avoid going through the roof.

   I like venting out horizontally because I can use a nice Seiho wall cap that has a great damper in it. Choices for roof caps are a lot slimmer.

1. 
   user-1035959 | Aug 16, 2012 03:48am | #3

   I've decided that I'm going to vent it through the roof. I read as much as I could about the pros and cons and I think the performance of the fan will be much better with a short run. There will be a backdraft damper to help prevent unwanted outside air from leaking in. I will also have the flex tubing insulated to help prevent condensation.

   A lot of the cons against going through the roof involve worries about a leak. I don't think the worrying is justified if the hole is properly flashed and sealed. I've already got a few holes in the roof -- vents, chimney, skylight -- and I've yet to have any problems with those.

   Thanks to you guys for chiming in.

1. 
   davidmeiland | Aug 17, 2012 07:54pm | #4

   Makes sense

   I ran my range hood out the roof in 8" to avoid putting an elbow in the duct. It is very easy to install a roof cap in most roofs.

   Bear in mind that the backdraft damper in the fan might be pretty leaky. Take a good look at it before closing it in.

2. 
   JohnWalker | Aug 25, 2012 01:29am | #5

   choice of roof vent cap?

   I don't want to hijack your thread but it is very timely for me too. We are about to put a roof on our new place and i am planning on preinstalling plumbing and bathroom vents/boots so they get shingled etc properly.

   My question is have you found any bathroom vents that look decent? Some of the sheet metal gooseneck ones look like they belong on a greasy spoon restaurant!

   Thanks

   John

2. 
   Geoffrey | Sep 02, 2012 01:31am | #6

   The right way is out the gable , pitch the vent line toward the gable, use hard pipe(6" is better) orient the seam on the pipe upward, and insulate as much of the pipe as you can. Use a sweep style elbow  or 2  45 deg. elbows to ruduce the  friction loss then run to the gable, pitching toward the gable.

   Install a timer and run the fan when you enter the bath and allow it to run for 15-20 mins. after you have left the bath to be assured of eliminating all the moisture ( 45 mins. total run approx. ).

   Through the roof : potential for leaks at roof penetration, back-draft damper in a vertical pipe requires more "push" from the fan to have it work effectively

   Good Luck

   Geoff