Ductless (also called a mini-split) is a type of HVAC system that doesn’t blow air through long expanses of ductwork. Instead, the climate-controlled air is generated by indoor air handling units attached to walls and/or ceilings — either in a single zone or multiple. The indoor units are connected to the outdoor condenser and compressor with hidden conduit. This setup offers a couple of important benefits. One, it’s easier to install, especially in space-challenged buildings. Two, it’s energy efficient.