An air-source heat pump, commonly referred to as a mini-split, is a heating & cooling system that has at least one outdoor and one indoor unit. The outdoor unit operates in variable speeds to maximize efficiency, using electricity to compress and expand refrigerant, making it either very hot or very cold. The hot or cold refrigerant is then pumped through copper piping to the indoor unit, where it fills up inside a coil. Inside air is then drawn through the coil, conditioning the air to be hot or cold that is then blown back into the space. The heat pump cycle will continue until the indoor unit sense that the set temperature has been met.