Abstract: The specification discloses a low-cost, simple, and efficient duct system for conveying heated and/or cooled air throughout a building. The system includes duct assemblies and transition components for interconnecting the duct assemblies. Each duct assembly includes an insulated duct having a rigid sleeve within at least one end. Each sleeve includes an abutment ring and orifices in the ring for permitting air to flow into the insulated layer to balloon the layer and improve its insulative effect. Each transition component includes a rigid external skeleton and a plurality of duct board panels fitted therein. After the sleeves are fitted within openings in the duct board panels, the tabs are deformed to retain the abutment rings in engagement with the panels.

Abstract: The specification discloses a low-cost, simple, and efficient duct system for conveying heated and/or cooled air throughout a building. The system includes duct assemblies and transition components for interconnecting the duct assemblies. Each duct assembly includes an insulated duct having a rigid sleeve within at least one end. Each sleeve includes an abutment ring and orifices in the ring for permitting air to flow into the insulated layer to balloon the layer and improve its insulative effect. Each transition component includes a rigid external skeleton and a plurality of duct board panels fitted therein. After the sleeves are fitted within openings in the duct board panels, the tabs are deformed to retain the abutment rings in engagement with the panels.