What is a key disadvantage of a Variable Air Volume (VAV) system in terms of indoor air quality?

Prepare for the Certified Indoor Environmentalist (CIE) Exam. Study effectively with flashcards and multiple choice questions. Each question includes hints and explanations to enhance understanding. Ace your exam with confidence!

Variable air volume systems deliver just enough supply air to each zone to meet its temperature needs, trimming the airflow as the load drops. This energy-saving approach can unintentionally reduce the amount of outdoor air reaching certain zones. Fresh outdoor air is what dilutes indoor contaminants and prevents buildup of CO2 and odors. When a zone’s airflow is minimized and outdoor air delivery isn’t increased to compensate, that zone can experience stagnation—air becomes aged, stale, and stuffy. So, while VAV can be energy-efficient and quiet, its drawback for indoor air quality is the potential for insufficient ventilation in some zones, leading to stuffy conditions.