DCV primarily saves energy by which approach?

• A. Increasing outdoor air during peak occupancy
• B. Reducing outdoor air delivery based on occupancy or contaminant levels while maintaining IAQ
• C. Eliminating filtration to reduce energy
• D. Heating the supply air more

Answer: (B)

Demand-Controlled Ventilation matches outdoor air delivery to how many people are actually present and to contaminant levels, rather than ventilating at a fixed rate. Sensors such as CO2 and occupancy detectors monitor the space and adjust ventilation so you provide enough fresh air to maintain IAQ, but not more than needed. When spaces are lightly occupied, outdoor air is reduced, which lowers the energy required to heat, cool, and dehumidify that air, and can also reduce fan energy due to lower overall air volume. When occupancy or contaminant levels rise, outdoor air is increased to preserve IAQ, still within the standards.

Raising outdoor air during peak occupancy would increase energy use unnecessarily. Removing filtration would degrade IAQ and isn’t a valid energy-saving strategy. Heating the supply air more just wastes energy and doesn’t address ventilation needs.