In the winter, a mini split draws heat from the outside air and circulates it into your home. In the summer, it reverses the process and draws heat from your interior air and releases it outdoors. It also dehumidifies the indoor air as it cools. The mini split serves as an air conditioner by absorbing the heat from the indoor air and pumping it outdoors. The mini split contains an indoor coil which, in turn, contains a very cold liquid refrigerant. As indoor air passes over the indoor coil, the refrigerant-cooled coil absorbs heat from the air and so quickly cools that air.