Systems and methodologies for alerting emergency responders

A method and system for alerting emergency responders. The method includes acquiring readings from one or more occupancy sensors of a building, determining an occupancy estimate based on the readings from the one or more occupancy sensors, storing the occupancy estimate in a server, determining whether an emergency event has occurred at the building based on one or more threat parameters received from one or more threat sensors. Further, the method includes outputting a notification to at least one external device of emergency responders and transmitting building information associated with the emergency event to the emergency responders when the emergency event has occurred. The building information includes the occupancy estimate.