There are two types of central air conditioning systems available to purchase and install. The first central a/c systems is a split-system central air conditioner and the second central air-con system is packaged air conditioner unit. A split system air conditioner has two parts. The first air conditioner part is the outdoor unit which has the condenser and the second a/c part is the compressor and the indoor unit which has the evaporator. The packaged air conditioner on the other hand has everything (evaporator, condenser and compressor) located in one place usually on the roof or in the concrete slab next to the foundation.