I'm planning on installing a Bathroom exhaust fan (Just a note, the port is 4") and am curious as to what kind of duct should be used.
I've heard that the duct should be insulated to prevent water backflow from condensation during the colder months as my attic is not environmentally controlled. The New York winters can also be rather cold sometimes, so this is especially a concern. I heard that code requires a rigid tube similar to aluminium.
What kind of duct is typically used for these installations? (Home Depot recommendations would be most appreciated because that's where I plan on purchasing the other components)