Insulated flexible duct provides a practical air-distribution solution where rigid ductwork is difficult to route. A reinforced flexible inner core is surrounded by thermal insulation and a durable outer jacket, helping reduce heat transfer, condensation and breakout noise in supply and extract systems. The duct can be formed around obstructions while maintaining a continuous airflow path, making it suitable for residential and commercial ceiling spaces. The range is available in multiple diameters and insulation ratings.