NextAire’s multi-zone gas heat pump features a programmable thermostat that controls the operation of the indoor unit. Desired occupied and unoccupied heating and cooling set points are programmed via the thermostat. Fan operation is determined by the position of the “On-Auto” switch, as well as by the mode of occupancy. The NextAire VRF outdoor unit heating or cooling mode is determined by the needs of the individual zones. If more zones (indoor units) are in need of cooling rather than heating, the outdoor unit operates in a cooling mode and modulates refrigerant flow in order to deliver the appropriate amount of cooling to the indoor units. If more zones (indoor units) are in need of heating, the VRF outdoor unit operates in a heating mode and modulates the refrigerant flow in order to deliver the appropriate amount of heating to the indoor units.