A ceiling diffuser is a supply air terminal mounted flush with or recessed into suspended ceilings, designed to distribute conditioned air into the room while providing architectural integration and adjustable airflow patterns. These are the most common diffuser type in commercial and residential applications, available in square, rectangular, and round configurations.
Design Characteristics
Ceiling diffusers typically range from 6 to 24 inches in size with effective areas of 80 to 500 square inches. Multiple deflector vanes or cones direct air in radial, linear, or adjustable patterns. Design throw distances extend 15 to 25 feet depending on blade angle and supply velocity. Standard models operate at noise criteria from 30 to 45, with pressure drops ranging from 0.05 to 0.25 inches of water column.
Installation and Selection
Mounting requires duct collar compatibility with ductwork sizing standards. Proper placement away from obstructions ensures uniform air distribution. Damper controls allow field adjustment of airflow direction and velocity. Selection requires matching diffuser CFM ratings to calculated supply requirements and verifying compatibility with suspended ceiling plenum construction and return air pathways.