A single package vertical air conditioner consists of a separate encased or un-encased combination of cooling and optional heating components, factory assembled as a single package, and intended for exterior mounting on, adjacent interior to, or through, an outside wall. The major components of the unit are arranged vertically, and may contain separate indoor grille(s), outdoor louvers, various ventilation options, indoor free air discharge, ductwork, wall plenum or a sleeve. Heating components may include electrical resistance, steam, hot water, gas, or no heat, but may not include reverse cycle refrigeration as a heating means. This equipment either alone or in combination with a heating plant, provides air-circulation, air-cleaning, cooling with controlled temperature and dehumidification, and may optionally include the function of heating and possible humidifying and ventilation.
A packaged terminal heat pump consists of a separate, unencased refrigeration system installed in a cabinet of similar function and configuration to that of a packaged terminal air-conditioner. It utilizes reverse cycle refrigeration as its prime heat source and should have available other supplementary heating by hot water, steam, or electric resistance.