What type of system typically does not use ducts to distribute air?

The mini-split system is known for its ductless design, which is a key characteristic that distinguishes it from other HVAC systems. Instead of relying on a network of ducts to distribute conditioned air throughout a space, a mini-split system consists of an outdoor compressor unit and one or more indoor air-handling units. These indoor units can be mounted on walls or ceilings, allowing them to directly blow air into the room without the need for ductwork.

This design not only simplifies installation in certain scenarios, such as in homes without existing ductwork, but it also enhances energy efficiency by minimizing the energy losses associated with ducted systems. Ducts can lose a significant amount of energy due to leaks or poor insulation, but with a ductless mini-split system, these concerns are greatly reduced.

Other options mentioned typically rely on ductwork to distribute air: forced air systems use ducts to deliver heated or cooled air; rooftop units usually involve extensive duct systems for air distribution; and ventilation-only systems often require ducting to bring fresh air into a building or space. Thus, understanding the features of mini-split systems highlights their unique position in the HVAC landscape.