The type of digital control building system designed to serve multiple zones is the ________.

• A. variable air-volume system
• B. constant volume system
• C. zoning integrity system
• D. central air-handling system

Answer: (A)

This question highlights how digital controls manage multiple zones by varying airflow to each area. A variable air-volume system uses a single air-handling unit to deliver conditioned air, while each zone has a VAV box with a damper that is controlled digitally. When a zone needs cooling or heating, its thermostat signals the control system to open that zone’s damper, increasing airflow there and reducing it in other zones as needed. This per-zone modulation lets different spaces achieve their desired temperatures using the same central system, delivering comfort where it’s needed and saving energy where it isn’t. A constant-volume system would push the same amount of air to every space, which isn’t as flexible for multiple zones. A central air-handling system refers to the equipment itself, not how it serves multiple zones, and a zoning integrity system isn’t a standard term for this concept. Therefore, the best fit is the variable air-volume system.