Caulk foam seal all penetrations into the attic space ie duct chases plumbing chases wiring electrical boxes from lights down below.
Bathroom fan insulation attic.
Bathroom vent fan ductwork insulation.
While insulating you can make some mistakes.
Options for venting a bathroom exhaust fan include best to worst.
If bath fan ducting isn t properly insulated the moist air from your house will condense inside the duct.
In un conditioned space such as an attic where otherwise your fan duct will be exposed to cold attic air in winter use insulated solid metal ducting or insulated flex duct.
If you see that your duct isn t insulated at all pick up duct insulation at the home center.
This is much easier to do if you have attic access because if you don t you usually have to remove some ceiling drywall and run the ducts along a joist.
Bathroom exhaust fans perform an important function by removing excess moisture from your home.
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.
The first step is to head to the attic.
Insulate the bathroom exhaust vent fan ducts.
Before you rush to the attic or go the roof to check for any leaks make sure the exhaust fan duct is properly insulated and run the fan more frequently for a prolonged period.
The building code requires a bathroom exhaust fan to vent outside the building so installation of a new bathroom fan necessarily involves installation of ductwork.
To avoid mistakes not running it at all consider installing switches with built in timers.