Static pressure is a measure of the force exerted by a fluid (such as air) when it is at rest. In the context of heating, ventilation, and air conditioning (HVAC) systems, static pressure is used to describe the pressure of the air within the ductwork and other components of the system. Static pressure is typically measured in units of inches of water column (in. w.c.) or pascals (Pa).

Static pressure is an important factor in the design and operation of HVAC systems, as it can affect the performance and efficiency of the system. High static pressure can indicate that there is a restriction or blockage in the ductwork or other components of the system, which can reduce the flow of air and affect the performance of the system. Low static pressure can indicate that there is a leak or other issue with the system, which can also impact performance.

Static pressure is typically measured using a pressure gauge or a manometer, and it can be affected by a number of factors, including the size and layout of the ductwork, the type and thickness of the material from which the ductwork is made, and the flow rate of the air through the system. Properly balancing the static pressure in an HVAC system can help to ensure that it operates efficiently and effectively, and it can also help to improve indoor air quality.