Sheet Metal Ducts: Made from galvanized steel or aluminum, these are a common and durable choice. They are rigid, non-porous, and resist mold growth. They are often round or rectangular and require insulation for temperature control.
Flexible Ducts: Often called "flex ducts," these consist of a metal wire coil covered in a flexible plastic or polymer layer with an outer insulation layer. They are a cost-effective and easy-to-install option for connecting rigid duct sections or navigating tight spaces, but are more susceptible to damage and airflow restrictions