Now where the discharge point is is going to be up to you.
Bathroom vent discharge into attic.
Exhaust air from toilet rooms and bathrooms shall not discharge into attic crawl space or other areas inside building.
The exhaust needs to vent outdoors.
M1507 2 exhaust air from bathrooms and toilet rooms shall not discharge into an attic crawl space or other areas inside the building.
M1501 1 air shall not be exhausted into an attic soffit ridge vent or crawl space.
You should never exhaust the bathroom fan directly into the attic.
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.
In order to accomplish this the roof has to have a hole cut in it.
It is because of this that many builders tend to advise against this method.
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.
No you cannot vent your bathroom exhaust fan into the attic.
Each bathroom has its own exhaust fan.
It may also violate a shingle warranty.
Health and structural issues when a bathroom is not vented properly.
Leaking and damaged vents as well as improperly installed ones also can cause problems.
If you re simply replacing the fan the ducts should already be set up for you.
Dumping bathroom exhaust into an attic or under roof space invites costly mold contamination frost under the roof in freezing climates moisture damage to roof sheathing possibly even plywood delamination or rot roof failures and shorter roof shingle life.
So what you want to do is you want to install a duct a vent duct and you can use flex duct for this.
Through the roof or an exterior gable wall.
A lot of options.
Exhausting of the bath vent fan must indeed be to the building exterior.
The next thing you need to do is make sure the exhaust is successfully making its way out of your home.
Rusted fixtures condensation from moisture laden air can cause health and structural problems as well especially when the bathroom vents discharge moist air into attics or crawl spaces.
Allowing the exhaust to vent into your attic can potentially cause several moisture problems.
That will take it from the bath exhaust fan to a discharge point.
Each fan vents separately out the roof.
The bath should be vented by either a 20 cfm continuous vent fan or a 50 cfm vent fan that is intermittent or switched.
Your attic is not a temperature controlled environment is never the same temperature as your living space and generally closer to the temperature outside.
Sizing a bathroom fan can be somewhat tricky as the information out there is all over the place.
