What is the definition of a mini-split HVAC system? This type of system is essentially an indoor and outdoor unit that are connected via a conduit. The indoor unit is installed inside the home and the outdoor unit is installed outside. The two units are connected with a conduit that contains the power and communication cables. The indoor unit houses the evaporator coil, blower motor, and other components necessary for air control. The outdoor unit houses the compressor, condenser fan, and condenser coil. The function of the system is to condition the air inside a building. It does this by taking in the outside air, cooling it down, and then circulating it through the home. The system can also be used to heat a building if it is equipped with a heat pump. In either case, the mini-split HVAC system is an energy-efficient way to keep your home comfortable all year round.