Window AC
Split AC

Split AC


A split-system air conditioner splits the hot side from the cold side of the system, as shown in the picture below

Inside a Split Air-conditioner

The cold side, consisting of the expansion valve and the cold coil, is generally placed into a furnace or some other air handler . The air handler blows air through the coil and routes the air throughout the building using a series of ducts. The hot side, known as the condensing unit , lives outside the building. In most home installations, the unit looks something like something in the picture beside:

The unit consists of a long, spiral coil shaped like a cylinder. Inside the coil is a fan , to blow air through the coil, along with a weather-resistant compressor and some control logic . This approach has evolved over the years because it is low-cost, and also because it normally results in reduced noise inside the house (at the expense of increased noise outside the house). Besides the fact that the hot and cold sides are split apart and the capacity is higher (making the coils and compressor larger), there is no difference between a split-system and a window air conditioner.

In warehouses, businesses, malls, large department stores and the like, the condensing unit normally lives on the roof and can be quite massive. Alternatively, there may be many smaller units on the roof, each attached inside to a small air handler that cools a specific zone in the building.

In larger buildings and particularly in multi-story buildings, the split-system approach begins to run into problems. Either running the pipe between the condenser and the air handler exceeds distance limitations (runs that are too long start to cause lubrication difficulties in the compressor), or the amount of duct work and the length of ducts becomes unmanageable. At this point, it is time to think about a chilled-water system.