Abstract: The present invention provides heating and cooling conditioning control in a multiple zone HVAC system to achieve enhanced user comfort and energy efficiency. In particular, the present invention provides a multiple zone HVAC control apparatus that senses and responds to changes in duct air pressure in order to prevent undesirable zone conditioning, energy loss, and register noise. The present invention offers particular benefit in high and medium velocity HVAC environments which typically suffer from pronounced deficiencies when zone demands diverge. Due to its ability to respond to changes in duct pressure, the present invention permits the conditioning of an increased number of zones without degradation in performance or user comfort. Additionally, the present invention provides a means to control elements within a multiple zone HVAC system including but not limited to heating and cooling sources, air circulator fans, zone dampers, and circulating pumps to achieve desired zone conditioning.