Indoor Air Quality (IAQ) Practice Exam 2025 – Comprehensive All-in-One Guide for Exam Success!

The distinction between natural and mechanical ventilation primarily revolves around the methods and mechanisms utilized to exchange air within an indoor environment. Natural ventilation relies on the movement of air created by natural forces, such as wind and temperature differences, and typically involves the use of open windows, doors, or vents to allow fresh air to enter while stale air exits. This method leverages passive airflow and generally requires no energy to operate, making it energy-efficient and cost-effective.

In contrast, mechanical ventilation depends on energy-driven systems, such as exhaust fans, air handling units, and HVAC systems, to regulate airflow. This approach allows for more controlled ventilation rates and can be tailored to specific indoor air quality needs, regardless of external environmental conditions.

While options regarding energy usage, maintenance, and the cooling purpose of ventilation systems present important points, they do not capture the core functional difference. Natural ventilation's reliance on open windows as its fundamental mechanism is the defining aspect that sets it apart from mechanical ventilation, which employs technology to facilitate air movement.