Is it OK to Vent a Bath Fan Out Through a Soffit?

Find out why it's OK to vent a bath fan out through a soffit as long as you actually cut a hole in the soffit and bring it out. Otherwise, you'll have problems with moisture.

LESLIE: Burt in Delaware is on the line and needs some help with a bathroom vent. What can we do for you?

BURT: So our house was built 21 years ago and I’m working on remodeling an upstairs bathroom. And I’m putting a – it’s a small, Jack-and-Jill bathroom with a commode and the shower in a separate area but it’s very small. So I’m putting a fan directly over the shower that’s on a GFI. And when they vented the old fan, they just stuck it out at the top on the – out by a soffit. And I’m just wondering – that might not be the best way but it’s still – is that still – does it still work, I guess, is what I’m asking?

TOM: Yeah, it’ll work. The thing is you want to make sure it actually comes through the soffit. I’ve seen bathroom-vent fans be dumped like in the soffit, expecting the warm, moist air to come through the perforation of the soffit.

BURT: Right.

TOM: But if it actually turns and vents straight out through the soffit, that’s fine. It’s probably a fairly short run, which means you’re not going to have any loss as you move that air along the duct and then bring it out.

BURT: OK. But you’re saying cut a hole in the soffit.

TOM: Absolutely. You don’t just want to dump it inside the soffit; you want to cut a hole and bring it out. Otherwise, you’re going to – ask for problems with moisture, as well as a fire hazard because all of that dust will collect up in that one space and that’s just not a good idea.

BURT: OK. Well, that’s what I need to know. Thank you very much.

TOM: You’re very welcome. Good luck with that project. Thanks so much for calling us at 888-MONEY-PIT.