Insulation problems will lead to other problems like the fan not being able to extract any humidity from the bathroom at all.
Bathroom exhaust duct in attic.
It may also violate a shingle warranty.
When venting a bathroom exhaust fan make sure to vent the air to the outside rather than into your attic where it can cause mold and mildew to form.
T he result of the insulation problem around a bathroom exhaust fan is either water stains or mold near the vent of your bathroom.
See bathroom vent duct termination for details about how to terminate the bath exhaust vent duct.
Ceiling fans vent either into the attic or outside through the roof.
Exhaust air from toilet rooms and bathrooms shall not discharge into attic crawl space or other areas inside building.
It cannot move air to a crawlspace or attic.
This section notes that air exhausted from the bathroom must be sent outdoors not indoors to the same residence or indoors to any other dwelling unit.
Example model ventilation codes.
If you have a bathroom with a separate enclosed toilet you ll also need an additional fan for that space.
While this may seem obvious homeowners may out of convenience direct the vent into either of these locations.
No you cannot vent your bathroom exhaust fan into the attic.
Your attic is not a temperature controlled environment is never the same temperature as your living space and generally closer to the temperature outside.
Another consideration to think about is the placement of your fan.
Depending on the location of the bathroom it may be easy to vent the exhaust fan through the roof.
Bathroom exhaust fans perform an important function by removing excess moisture from your home.
It is because of this that many builders tend to advise against this method.
One attic mounted fan for two bathrooms one in line centrifugal fan can be mounted in the attic to exhaust the moisture from two bathrooms.
This involves running ductwork from the fan usually though an attic and out through the roof.
You should never exhaust the bathroom fan directly into the attic.
There are wall mount exhaust fans as well as ceiling exhaust fans.
In order to accomplish this the roof has to have a hole cut in it.