Which component is primarily responsible for delivering conditioned air to individual zones in a VAV system?

• A. Return grille
• B. AHU coil
• C. Economizer damper
• D. VAV box

Answer: (D)

In a VAV system, each zone gets its conditioned air through a VAV box. The central AHU conditions the air and sends it through the building, but it’s the VAV box in each zone that modulates how much of that air actually enters the space. The box uses a damper (and sometimes a small reheating element) to adjust airflow to meet the zone’s thermostat setpoint, delivering the right amount of conditioned air to that specific area.

The other components don’t handle zone-by-zone delivery: the return grille simply collects air returning to the AHU; the economizer damper controls outdoor air at the system level for energy savings; and the AHU coil conditions the air for the whole system, not per zone. Therefore, the VAV box is the element responsible for delivering conditioned air to individual zones.