Flexible duct (or "flex duct") is a bendable, tube-shaped conduit used in HVAC systems to distribute air from main metal trunk lines to individual room vents. It consists of a flexible wire helix encased in a durable plastic liner, surrounded by fiberglass insulation, and wrapped in an outer vapor barrier jacket.
Key Types of Flexible Ducting
Insulated Flex Duct: Standard for residential HVAC heating and cooling to prevent energy loss and condensation.
Non-Insulated Flex Duct: Best for exhaust-only applications like bathroom fans, kitchen hoods, or clothes dryers.
Heavy-Duty Aluminum Flex Duct: Semi-rigid all-metal piping often required by local building codes for transition dryer vents due to fire safety.