What is the definition of a mini-split? A mini-split is an air conditioning system that uses individual units for each room or area in a home or building. This type of system is very efficient because it can be controlled independently, allowing for different temperatures in different rooms. Mini-splits are also known as ductless systems because they don’t require ducts to be installed. They are a great way to cool or heat areas of the home that may not be located near the main air conditioning or heating unit. Mini-splits are usually wall mounted or ceiling mounted and use a single outdoor unit that supplies air through an indoor unit. The indoor units may have different settings, such as cooling and heating, fan-only, and dehumidification. They are also very energy efficient, since they do not require forced air to circulate through the entire home. Mini-splits are a great solution for homes or buildings that do not have the space or need for a central air