A rightly sized central air conditioner is of prime importance because both an over-sized AC and an under-sized AC is a wastage of energy. Sizing of an air conditioner typically means the capacity of the air conditioner or to put it simply, the amount of heat the system can remove from an enclosed space. The amount of heat that needs to be removed depends on a number of factors like the size of the house, exposure to sun, quality of insulation, number of windows and a lot of other factors. However, only proper load calculation of an enclosed space will be able to determine the size of the air conditioner that is required. Hence, it is necessary to employ an HVAC technician who will do the accurate load calculation of a building.