The central air conditioning system is not preferred by all as the maximum population live in apartments, condos and bungalow. Window air conditioners first developed in the late 19th century. The first developed systems were known as window bangers as they created a lot of noise. However, with advancement in technology these systems have been largely modified. The present systems are not at all noisy and more efficient. Moreover, the large demand for these systems is due to the fact that these systems are rather cheap as compared to split systems. Partial ventilation, compact size, no installation procedure, easy transportation and long durability are some of the many reasons which have made these systems much in demand.