Bath Fan Vents Into Attic

We explain how to install bathroom exhaust fans or vents the vent ducting.

Bath fan vents into attic.

No you cannot vent the bathroom exhaust fan into the soffit vents. Bathroom code does address the issue of moving odor and moisture laden air from the bathroom to the outside. This setup requires an in line centrifugal fan mounted in the attic drawing air simultaneously from both bathrooms see photo. In all cases the ducting needs to conduct the exchaust to the building exterior and needs to terminate in an animal proof vent cover.

I see many questions about leaking bath exhaust vents. In fact i have seen numerous houses that haven t yet had signs of mold with the bath fan venting incorrectly. Most bath vents for homes are 3. Can you vent a bathroom exhaust fan into the soffit vents.

You d often blow air from one bathroom into the other and local building inspectors wouldn t approve it. Venting through a roof vent or exhausting them in the attic could cause moisture problems and rot. I would by lying if i told you that it will cause problems it may be totally fine. Now where the discharge point is is going to be up to you.

This article series explains why bathroom vent fans are needed and describes good bath vent fan choices necessary fan capacity and good bath vent fan and vent duct installation details. Surprisingly bathroom fans are not required by some building codes. Bathroom fan vent code requirements include no venting to attic areas to help reduce mold or structural problems. I recommend replacing the vent pipe with insulated vent pipe.

Bathroom ventilation codes require a bathroom exhaust fan to vent to the exterior not the attic for health and structural reasons. How to install a bathroom vent fan. That will take it from the bath exhaust fan to a discharge point. Bathroom ventilation fan duct routing routing a bath vent duct down out or up through an attic or roof out.

So what you want to do is you want to install a duct a vent duct and you can use flex duct for this. If you vent the bathroom exhaust fan to close to the soffit vents which are vented plates under your homes outer edge and roof your home the air can be sucked right back into the attic from the soffit. The lowdown on venting your bath fan into an attic is that it can be done but it should terminate on the outside. But while you can t have two fans with one vent you can make one fan and one vent serve two bathrooms.

The best exhaust fan venting is through smooth rigid ducts with taped joints and screwed to a special vent hood. Vent your bath and kitchen exhaust fans through the roof through a special roof hood. All municipalities have different requirements but some do not draw a hard line on requiring exhaust fans. Next make sure it is securely fastened on both ends of the pipe.