The quantity of air moving through a fan system is expressed in _____?

The quantity of air moving through a fan system is expressed in CFM, which stands for Cubic Feet per Minute. This measurement indicates the volume of air that is moved by the fan within a minute and is crucial for understanding the capacity of ventilation and air distribution in a building or space. CFM is a key parameter in HVAC systems, as it helps to determine whether the system can adequately supply fresh air, maintain proper airflow, and ensure comfort conditions.

In contrast, RPM, or Revolutions Per Minute, measures the speed at which the fan blades are spinning but does not directly indicate the volume of air being moved. BTU, or British Thermal Unit, is a measurement of thermal energy and is used to describe heating and cooling capacity, but it does not relate to airflow. Wattage is a measure of electrical power consumed by a fan but does not provide information about the air movement itself. Thus, CFM is the most appropriate unit for expressing the quantity of air in a fan system.