An air diffuser configured to be positioned in a raised floor, in which the air diffuser includes a sleeve having a first end and a second end with an air flow passage extending through the sleeve from the first end to the second end, a diffuser face disposed at the first end of the sleeve and configured to be exposed to an environment in an installed position within the raised floor, a damper disposed at the second end of the sleeve, and a plenum chamber defined within the sleeve between the damper and the diffuser face.