Options for venting a bathroom exhaust fan include best to worst.
Bathroom ventilation fan into attic.
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.
This setup requires an in line centrifugal fan mounted in the attic drawing air simultaneously from both bathrooms see photo.
How do i properly vent a bathroom fan into an attic.
No you cannot vent your bathroom exhaust fan into the attic.
Never allow the duct to simply blow into an attic crawlspace or other enclosed area.
The correct way to vent a bathroom fan through an attic is to terminate the vent either to the roof or to the gable wall.
In those areas ventilation in bathrooms is required but it can be from a window or fan your choice.
All municipalities have different requirements but some do not draw a hard line on requiring exhaust fans.
Bathroom ventilation fan duct routing routing a bath vent duct down out or up through an attic or roof out.
Note that the bathroom vent fan must always exhaust to the outdoors.
How to install a bathroom vent fan.
Also the installation of the bathroom exhaust fan will go much quicker if you ask a spouse or friend to help be in the attic while you work from below or to hand you tools while you re on.
Bathroom fan vent code requirements include no venting to attic areas to help reduce mold or structural problems.
The vent hood will have a little flap that opens when air is blowing.
We explain how to install bathroom exhaust fans or vents the vent ducting.
Second during cold winters you ll be blowing warm moist air onto a cold surface the roof vent and roof plywood.
First you ll partially block your roof vent with the piping reducing the flow of cooling air through your attic.
If you re tempted to vent your exhaust fan through an existing roof vent or even vent it into the attic don t do it.
But while you can t have two fans with one vent you can make one fan and one vent serve two bathrooms.
Bathroom exhaust fans perform an important function by removing excess moisture from your home.
You should never exhaust the bathroom fan directly into the attic.
In all cases the ducting needs to conduct the exchaust to the building exterior and needs to terminate in an animal proof vent cover.
Either way the vent will have to go directly to the outside and installed with a vent hood cover.
Bathroom ventilation codes require a bathroom exhaust fan to vent to the exterior not the attic for health and structural reasons.
Surprisingly bathroom fans are not required by some building codes.
Your attic is not a temperature controlled environment is never the same temperature as your living space and generally closer to the temperature outside.
This article describes routing bath exhaust fan duct upwards through an attic or roof space or downwards through a floor or crawl space.
