It is very important to verify proper manual and automatic control of an HVAC air system. A balanced supply and exhaust will help ensure sufficient ventilation by meeting minimum air exchange rates, removing airborne contaminants which can affect air quality, and reducing operating costs. The supply flow for an area may also affect the room pressurization in relation to an adjacent room or hallway, which can cause drafts or difficulty opening and closing doors.
Capture hoods, rotating vanes, and thermal anemometers are the most common choices used to verify proper minimum flow rates; confirm proper operation of dampers, controls, and fans; and ensure the efficient use of energy.