Abstract: A retrofittable heating and air conditioning system for a single family dwelling including a heater and air conditioning furnace system connected to individual zones of a building by a series of output ducts. Each opening of a duct to an individual zone may have a unique, fully sealing, controllable output register assembly. Also, in each zone is a thermostat for sensing the zone temperature and for providing a means for the user to control the temperature of that zone. The system further includes a master controller with such temperature controlling features as a universal zone controller, individual zone controllers, and a timer. Finally, the system includes a central controller for controlling the register assemblies and the air conditioning, heating, and fan with respect to instructions set by the individual zone registers and the master controller.