What is the definition of a mini split voltage? Mini split voltage is an electrical system that uses smaller, multiple indoor units to cool or heat a space. This type of system is most commonly used in homes, apartments, or small commercial buildings. The indoor units are connected to a single outdoor unit, which is connected to the local power source. The outdoor unit contains a compressor and condenser, which is responsible for cooling or heating the air and circulating it throughout the home. The indoor units are connected to the outdoor unit with copper refrigerant lines that carry the cooled or heated air to each room. This type of system is more efficient than traditional HVAC systems due to the smaller size and the fact that each room can be cooled or heated independently. It is also more cost-effective since each room can be set to a different temperature, allowing for energy savings.