VAV systems are commonly used in a wide variety of commercial and institutional buildings, including hotels, hospitals, office buildings, and retail applications. These systems are usually seen as being beneficial to building owners and occupants, in that they both save energy and can provide a high level of comfort.
VAV systems are different from constant volume systems in that they adjust the airflow to the occupied space based on the building's heating and cooling requirements. When less heating or cooling is needed, the fan system reduces the amount of air that is supplied to the space.