Package Air Conditioners is a device which is used for the cooling and heating of a large commercial building such as shopping malls, offices, hospital etc. Its working principle is same as that of a domestic window air conditioner but it has a large size and higher cooling or heating capacity. The complete system is enclosed in a hard box type casing and the processed cool air flows through the metal ducts to different areas of the building. Package air conditioner is also used to provide heat by the use of electrical strip heating. It is a compact unit as all of the equipments are located in a single casing.