What is a mini-split? A mini-split is a ductless heating, ventilation, and air conditioning (HVAC) system that heats and cools individual rooms or zones efficiently, without needing extensive ductwork, by connecting an outdoor compressor to one or more indoor air-handling units via a smalll conduit. This is a significant energy saver over central a/c systems as there are no duct energy losses making it ideal for older homes, additions or spaces without existing ducts, offering precise temperature control.