How does increasing the CFM affect the static pressure in an HVAC system?

In an HVAC system, CFM, or cubic feet per minute, measures the airflow volume passing through the system. When CFM is increased, it typically leads to a rise in static pressure. This happens because as more air is moved through the ducts, the friction between the air and the walls of the ducts increases. Consequently, the system has to exert more pressure to push that additional air through, resulting in higher static pressure readings.

Static pressure is crucial for ensuring that air moves efficiently throughout the system, reaching all areas intended without significant losses. When a system is operating under higher static pressure, it can indicate that there may be restrictions or complications, such as duct sizing issues or obstacles within the system. Understanding this relationship helps HVAC professionals design systems that handle airflow efficiently while keeping static pressure within acceptable limits for optimal performance.