Bathroom Exhaust Fant

7 Replies

Hello DIY-er's,

The exhaust fan in my townhouse is out of order. So I purchased a Panasonic Whisper Ceiling Fan and a roof vent to install and replace the old exhaust. After removing the old fan, I realized the old Nutone fan was venting the air into the attic... Our inspector didn't find any signs of mold. So is it common to have exhaust fans to vent to the attic in the northwest coast Florida? The weather up here is not as hot as south Florida and the weather here does can get in the low 40s. I am concerned about make a hole in our roof to vent the fan on my own because I don't want any leaks. Should I just exhaust into the attic? Or should I contract someone to install the new ceiling fan and cut a hole in my roof to vent the air? 

Any thoughts from the experienced DIYers?? The attic is unfinished and there is loose-fill insulation. My concern is trying to make the hole bigger and to fit the panasonic exhaust fan, when there is fiberglass insulation hanging out above me. Although I think it would be so fun to do it on my own! But I also want a functional and nice bathroom. I will post a photo below.

Here are some pix. The vent was extremely small. 

I don't know about Florida. Best practice is to take it outside.  If possible I usually vent them out a side wall. 

They should be exhausted to the outside, other wise whats the point, vent one room to only allow the air back into another. You can vent them to the outside wall if the bathroom has an exterior wall, or through the roof

I was helping out my father in law and found his master bath fan had been venting into the subfloor between the basement and main level for some 40 years. I saw no signs of mold but had no idea how often it was used. Funny thing was there was an exhaust port on the exterior but the venting line was never connected to it. I pulled out more drywall and connected it properly and then repaired the drywall. My understanding of our codes here is that bathroom fans need to vent outside rather than an attic even if the attic is vented. If this is a DIY it's only a little more effort to do it right (assuming your codes are similar) plus it's one less thing for the inspector to call out when you sell.

@Michael Gessner It's a town home and there aren't any windows in the bathroom. And I am trying to figure out if it is common to exhaust to the attic in Florida.

Its common in alot of places, not because its right but instead because its easier for lazy contractors or diy people.  Without exterior vent, your pulling warm moist air and dumping it into unconditioned space.  A properly installed roof vent is the way to do it. 

Exhaust fans should do just that, exhaust foul or humid air outside of a space. Not displace it, exhaust it in to the atmosphere. Venting outside is International Building Code.

Buy a roof vent with a flashing shroud, backdraft damper, and flexible duct. Cut a hole in the roof, and lap the shingles over the upslope side of the roof vent flashing shroud. Use a roofing mastic to seal the edge of the roof vent flashing shroud to the roof sheathing under the shingles.

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