A system (102; 300) for determining an effective temperature set-point for one or more Variable Air Volume ("VAV") controllers in a heating, ventilation, and air conditioning (HVAC), the system comprising: a sensor interface module configured to receive one or more dynamically sensed parameters from a plurality of sensors (204, 206, 208) strategically placed within and outside of a building; a standard reference module configured to retrieve one or more static parameters corresponding to building configurations and temperature thresholds from a memory unit; a correlation engine coupled with the sensor interface module and the standard reference module, wherein the correlation engine is configured to dynamically determine the effective temperature set-point for each VAV controller associated with a particular pre-defined zone in the building by establishing a correlation between the one or more dynamically sensed parameters and static parameters corresponding to that zone; said one or more VAV controllers communicatively coupled with the correlation engine, wherein each VAV controller is configured to receive the respective effective temperature set-point value from the correlation engine via a VAV interface and to establish the temperature set point for associated zone based on the received value; the system being characterised in that: the one or more static parameters includes the total number of sub-zones in the pre-defined zone, the one or more dynamically sensed parameters includes the sum of occupied sub-zones in the pre-defined zone, and the correlation engine is configured to dynamically determine the effective temperature set-point based on the proportion of sub-zones in the pre-defined zone which are occupied. a sensor interface module configured to receive one or more dynamically sensed parameters from a plurality of sensors (204, 206, 208) strategically placed within and outside of a building; a standard reference module configured to retrieve one or more static parameters corresponding to building configurations and temperature thresholds from a memory unit; a correlation engine coupled with the sensor interface module and the standard reference module, wherein the correlation engine is configured to dynamically determine the effective temperature set-point for each VAV controller associated with a particular pre-defined zone in the building by establishing a correlation between the one or more dynamically sensed parameters and static parameters corresponding to that zone; said one or more VAV controllers communicatively coupled with the correlation engine, wherein each VAV controller is configured to receive the respective effective temperature set-point value from the correlation engine via a VAV interface and to establish the temperature set point for associated zone based on the received value; the system being characterised in that: the one or more static parameters includes the total number of sub-zones in the pre-defined zone, the one or more dynamically sensed parameters includes the sum of occupied sub-zones in the pre-defined zone, and the correlation engine is configured to dynamically determine the effective temperature set-point based on the proportion of sub-zones in the pre-defined zone which are occupied.