Packaged Terminal Air Conditioning System

A method of operating an air conditioning unit, the method comprising:

• receiving, via an internal inlet, internal air from an internal area;
• receiving, via an external inlet, external air from an external area;
• receiving, via a heat exchanger, the internal air from the internal inlet;
• receiving, via the heat exchanger, the external air from the external inlet;
• generating, via the heat exchanger, a conditioned mix of the internal air and the external air;
• and
• outputting, via an internal outlet, the conditioned mix of the internal air and the external air into the internal area.

A packaged terminal air conditioning (PTAC) unit for use in a wall sleeve in a wall having an external side and an internal side, the external side facing an external area, the internal side facing an internal area, the internal area being separated from the external area by the wall, the PTAC unit comprising:

• an internal inlet configured to receive internal air from the internal area;
• an external inlet configured to receive external air from the external area;
• a heat exchanger arranged to receive the internal air from the internal inlet and to receive the external air from the external inlet and configured to generate a conditioned mix of the internal air and the external air;
• and
• an internal outlet configured to output the conditioned mix of the internal air and the external air into the internal area.