A packaged terminal air conditioner (often abbreviated PTAC) is a type of self-contained heating and air conditioning system commonly found in hotels and apartment buildings. Many are designed to go through a wall, having vents and heat sinks both inside and outside. Different standard dimensions are found in the market including 42×16 inches (1067 x 406 mm), 36x15 inches, and 40x15 inches. Although PTACs are used mostly to heat or cool a single living space using only electricity (with resistive and/or heat pump heating), you can find cooling only PTACS with external heating through a hydronic heating coil or natural gas heating.. Typical PTAC heating and cooling capacity values range from 2 kilowatts (7000 BTU/Hr) to 5.5 kilowatts (19000 BTU/Hr) nominal. One characteristic of PTACs is that drain piping is not required because the condensate water extracted from the air by the evaporator coil is drawn by the condenser fan onto the condenser coil surface where it evaporates.

PTACs are commonly installed in window walls and masonry walls. Their installation typically requires the following: 1) Louver 2) Metal sleeve 3) Heating Coil 4) The PTAC 5) Room Enclosure