A split duct AC is an air conditioning system that uses two separate components, an outdoor unit and an indoor unit, to cool a home or business. The outdoor unit contains the compressor, condenser, and fan, while the indoor unit contains the evaporator coil and blower. The two units are connected by copper refrigerant lines, which carry the refrigerant between the two units. The outdoor unit is typically located outside the building, while the indoor unit is located inside. The two units work together to cool the air in the building, with the outdoor unit drawing in outside air and cooling it, while the indoor unit circulates the cooled air throughout the building. Split duct AC systems are popular because they are energy efficient and can be installed in a variety of configurations. They are also relatively quiet, making them ideal for use in residential and commercial buildings.