What is the definition of a multi split AC system? A multi split AC system is a type of air conditioning system that is made up of two or more indoor units that are connected to a single outdoor unit. This type of system offers a great deal of flexibility in terms of cooling and heating options, as it allows you to control the temperature in different rooms or areas of a building. It also allows you to manage the individual indoor units independently, meaning you can have different temperatures in different areas. The main advantage of a multi split system is that it is very energy efficient, as it does not require a lot of energy to operate. Additionally, multi split systems are very quiet, making them ideal for residential and commercial settings. They are also relatively easy to install, and require fewer external components than other AC systems. Ultimately, multi split AC systems are an efficient and cost-effective way to keep your home or business comfortable.