NCIDQ IDFX Practice Exam

Which type of air system is characterized by having several ducts leading out from one box?

1. Constant volume system

2. Multizone system

3. VAV system

4. Single-zone system

The correct answer is: VAV system

The type of air system characterized by having several ducts leading out from one box is the Variable Air Volume (VAV) system. In a VAV system, a central air handling unit supplies air to various zones within a building, with variable volume dampers used to control the flow of air to each zone independently. This allows each space to maintain its own temperature, enhancing comfort and efficiency by adjusting the airflow based on real-time heating or cooling demand. The numerous ducts emanating from a single box—typically an air handling unit—enable the delivery of conditioned air to multiple areas, providing flexibility in temperature control and energy savings compared to systems that supply a constant volume of air. The VAV system is particularly advantageous in larger buildings where different spaces may have different occupancy levels and heating or cooling needs. In contrast, a constant volume system delivers a consistent volume of air regardless of the heating or cooling demand, thereby not utilizing multiple ducts effectively in the same way. A multizone system typically refers to a setup where several distinct areas can be controlled separately, but this can also involve various configurations beyond duct distribution from a single box. A single-zone system, on the other hand, manages the air supply for only one designated space, which does not involve multiple