Ducted heating systems use air ducts to distribute heated air throughout a building. The return air plenum via the ceiling in this video is responsible for circulating the cool or heated air back to the air conditioning system to be re-conditioned. The return air ducts must be airtight in the wall plenum to ensure the system operates efficiently and effectively. In this video, the return air duct was too short and needed to be extended in order to make it air-tight a little lower down inside the return cavity. Several negative consequences can occur if the return air ducts are not airtight. Firstly, air leaks can cause the system to lose efficiency and pressurize your home as heated air escapes from the ducts before it can be circulated throughout the building. This can result in poorer indoor air quality, increased energy consumption and higher utility bills. Secondly, leaks can allow unfiltered air from the roof space to enter the system. This can lead to a buildup of dust and allergens in the ducts, which can be circulated throughout the building and cause health problems for occupants sensitive to these particles, especially asthmatics. To avoid these and other problems associated with air leaks in ducted heating systems, the return air plenums in wall cavities and ducts must be appropriately sealed and airtight. This can be achieved using Air barrier tapes, XPS boards, caulk products and other sealing materials explicitly designed for ductwork mechanical systems.
Air Tightness products
Air Tightness testing