The variable air volume (VAV) systems that use variable speed fans and the more recently developed control methods like the duct static pressure reset (DSPR) control are widely used in Hong Kong. The performance of the DSPR control and constant duct static pressure control method in an existing office building in Hong Kong was tested. The successful application of the control method requires proper matching between zone cooling loads and flow capacities of the supply fan and the VAV boxes

and adequate ductwork design.