View Full Version : bath fan vents - combine with Y to one large roof jack?

01-25-2012, 08:22 PM
I have two bathrooms that share a common wall. I installed a Broan combination 110 CFM fan/light/heater (http://www.broan.com/display/router.asp?ProductID=100668) in one with 6" sheetmetal outlet to an AirKing PRC6R (http://www.airkinglimited.com/pages/exhaust/roofcaps1.html) roof cap. It works great, vents the bathroom very quickly and quietly, and the wife loves the heater.

I want to add a Broan fan (http://www.broan.com/display/router.asp?ProductID=100412) with a 6" outlet to the other bathroom. It is 110 CFM.

I don't really want to punch another hole in the roof unnecessarily. I think the 6" sheetmetal ducting should be more than enough, even in the unlikely event both fans are running simultaneously. And when only one is on, the other should prevent backflow with the integrated damper, right? And the Y junction should help at least direct the flow in the right direction.

Or is my thinking totally wrong?