An interactive system for controlling the operation of an HVAC system is provided that comprises a thermostat for initiating the operation of the HVAC system in either a full capacity mode of operation or at least one reduced capacity mode of operation, and a controller for an outside condenser unit having a condenser fan motor and a compressor motor, the controller being capable of operating the compressor in a full capacity mode and at least one reduced capacity mode. The system also comprises a controller for an indoor blower unit having a blower fan motor, the controller being capable of operating the blower fan motor in a full capacity mode and at least one reduced capacity mode. The system further includes a communication means for transmitting information between the outside condenser unit controller and at least the indoor blower controller, where the information relates to the operation of the indoor blower and the outdoor condenser unit. The indoor blower controller responsively controls the operation of the blower fan motor in a full capacity mode or a reduced capacity mode based on the information received from the outdoor unit controller, and the outdoor unit controller responsively controls the operation of the compressor in a full capacity mode or a reduced capacity mode based on the information received from the indoor blower controller.