A factory-installed option for Energence® 7.5- to 25-ton rooftop units, the MSAV® (multistage air volume) supply fan technology helps systems to reduce energy use while still meeting comfort requirements. By using a variable-frequency drive and patent-pending control algorithms, the option allows the unit to lower airflow for a dramatic reduction of energy use in multiple modes of operation — including part-load cooling, heating, ventilation, and free-cooling operation — resulting in year-round utility savings. The supply fan technology allows quick and easy start-up of the unit, while also offering users the flexibility to customize airflow settings by making simple changes in the unit’s control system. According to the manufacturer, it also offers occupied and unoccupied supply fan operational energy savings; improved system reliability with soft starts, reducing (torque) wear and tear on major components such as fan motors, belts, and bearings; part-load (IEER) energy savings, with efficiency improvements up to 27 percent; and improved dehumidification performance. The unit is code compliant to ASHRAE 90.1-2010 and California Title 24 requirements for single-zone VAV systems.