Quantcast

Questions on venting bath exhaust fan

Help Support House Repair Talk:

terry47

Member
Joined
Jul 16, 2011
Messages
8
Reaction score
2
We are replacing an exhaust fan and want to replace the venting. We have been reading about many methods and are getting more confused. There doesn't seem to be one "right" way. So I thought I would ask for your experiences.
The flex hose seems to be the most common material. The only drawback I see is dust accumulation in the accordion folds especially in the curves. and the moist air causing it to stick.
Broan recommends using rigid ducting that is insulated so in cold weather the moist air will not condense into liquid. But that doesn't seem possible because the open end of the ductwork will come in contact with the cold weather when it reaches the edge of the house and the metal will still get cold. (we live in the north)
Has anyone used pvc pipe?
 

Snoonyb

Well-Known Member
Joined
Sep 30, 2006
Messages
4,046
Reaction score
782
What ever material you use will assume the ambient temperature, and while the amount of condensation may vary lightly from material to material, it will still occur.
 

ctviggen

Member
Joined
Jun 19, 2020
Messages
15
Reaction score
0
Location
Connecticut
I've used rigid duct then insulated it somehow (and supported the duct if necessary). I tape the seams. I've used that bubble wrap stuff (two sheets of metallic material with bubble wrap inbetween and also insulation wrap. Ideally, you also bring the duct high, then have a downward tilt toward the outside. This lets any condensation run outside.
 

Jeff Handy

Well-Known Member
Joined
Nov 20, 2019
Messages
694
Reaction score
200
Location
Chicago suburbs
Rigid metal four inch is best, but heavy spiral foil like for a dryer duct is also fine.

The plastic or foil vents with a Slinky type of wire coil support are worthless, too saggy and flimsy.

You can buy 4 inch flex duct insulation to cover these, which will minimize the condensation that otherwise might drip back out of the bath fan.

A roof vent with a gravity damper is a preferred exit point.

You can hang the vent line somewhat like a dishwasher high loop, so that a portion of the vent near the end is higher, to prevent condensation running back to the fan.
 

Latest posts

Top