A supply air diffuser is a terminal outlet device that distributes conditioned air from the ductwork into occupied spaces while providing mixing, velocity control, and aesthetic appearance. Diffusers are available in multiple configurations including ceiling-mounted, wall-mounted, and floor-mounted styles, each designed to throw air patterns 8 to 15 feet into the room. Modern diffusers incorporate adjustable dampers to balance airflow and optimize thermal comfort.
Design and Performance
Supply diffusers are rated by throw distance, spread pattern, and noise generation. Standard ceiling diffusers handle 50 to 400 CFM (cubic feet per minute) while maintaining noise levels below 35 decibels. The four-way or radial throw pattern distributes air evenly to all room areas while minimizing drafts and stratification.
Practical Applications
Diffusers must be sized appropriately to deliver specified airflow without exceeding 0.5 to 1.0 feet per second at occupied zones. Proper mounting height, typically 8 to 10 feet above floor level, ensures adequate mixing before air reaches occupants. Diffuser selection significantly impacts both thermal comfort and acoustic performance within the conditioned space.