Define Demand Control Ventilation (DCV).

• A. A strategy to reduce outdoor air delivery based on occupancy or contaminant levels to save energy while maintaining IAQ.
• B. A method to maximize outdoor air at all times.
• C. A device that measures humidity.
• D. A schedule to exhaust air only.

Answer: (A)

Demand Control Ventilation is a strategy that modulates outdoor air delivery based on actual occupancy or contaminant levels, aiming to save energy while keeping indoor air quality acceptable. By using sensors such as CO2 (a common proxy for how many people are present) or other pollutant indicators, the system can lower ventilation when spaces are less occupied and raise it when occupancy or contaminant generation increases. This keeps IAQ within required limits without the energy penalty of always supplying maximum outdoor air.

The other options don’t fit because DCV is not about always maximizing outdoor air, nor is it simply a humidity-measuring device, and it’s not a fixed schedule for exhausting air.