What is The Definition Of A Mininsplits? A Mini-split is a type of air conditioning system that is ideal for smaller areas or buildings. It is a ductless system that consists of two main parts, an outdoor condenser unit and an indoor air-handling unit. The condenser unit contains the compressor, condenser coil, and expansion valve, while the indoor unit contains an evaporator coil, fan and filter. The condenser unit is installed outside of the building and the indoor unit is mounted on the wall inside of the building. Mini-splits are often used as a supplement to existing central air conditioning, or as a replacement for window air conditioners. They are energy efficient and provide a flexible, individualized heating and cooling solution. The advantages of mini-split systems include the ability to provide cooling to a single room without wasting energy cooling other areas of the building, as well as providing zone comfort, which allows for customizing temperatures in multiple rooms.