What is a Split System?
A split system is an air conditioner which has two parts. The indoor unit (the evaporator) and the outdoor unit (the condenser). The evaporator is mounted inside the room, and is connected by refrigeration piping to the condenser, which is mounted outside.
Split system air conditioners operate on a vapour compression refrigeration cycle. This is a thermodynamic process of refrigerant changing state (from a vapour to a liquid to a vapour again) which enables air conditioners to heat or cool.