This document provides guidelines for proper duct installation and sealing. It discusses different types of duct materials like sheet metal, flex duct, and duct board. Key points of duct design include getting ducts inside the building envelope, using sheet metal elbows for tight turns, proper take-off spacing, and sizing return grilles and ducts adequately. Duct sealing is critical using products like mastic, UL181-rated foil tape, or butt tape applied correctly. Pressure balancing between zones can be achieved using transfer grilles or jumper ducts. Following these guidelines helps ensure efficient duct performance and reduced energy costs.