In HVAC calculations, what unit represents the efficiency and speed of air movement through a system?

In HVAC calculations, the unit that represents the efficiency and speed of air movement through a system is CFM, which stands for Cubic Feet per Minute. This measurement is crucial because it quantifies the volume of air being moved by the HVAC system within a specified timeframe.

When designing or assessing an HVAC system, understanding the air flow in CFM helps ensure that the system can effectively heat or cool a space. Proper airflow is essential for achieving the desired temperature and maintaining comfort in a building. Additionally, CFM is a key factor in determining whether equipment is adequately sized, which in turn affects energy efficiency and overall performance.

The other options pertain to different aspects of HVAC calculations. BTU (British Thermal Unit) measures heating or cooling capacity but not airflow. FPM (Feet per Minute) is a unit that indicates the velocity of air movement, which is related but not the measure of total air volume like CFM is. HP (Horsepower) is a unit of power used to indicate the capability of motors and compressors within HVAC systems rather than airflow efficiency. Therefore, CFM is the most accurate unit for discussing the efficiency and speed of air movement in HVAC contexts.