Differential pressure is the difference in pressure between two points in a system. It is typically measured in units of pounds per square inch (psi) or inches of water column (inWC). Differential pressure is an important concept in fluid dynamics and is used to measure the flow rate of a fluid. It is also used to measure the pressure drop across a filter, a valve, or other components in a system. Differential pressure is used in many industries, including HVAC, medical, automotive, and aerospace. Differential pressure is a key indicator of system performance and can be used to detect changes in system conditions, such as a clogged filter or a malfunctioning valve. Differential pressure can also be used to monitor the performance of pumps, compressors, and other equipment. By monitoring differential pressure, engineers can detect problems before they become serious and take corrective action.