Which measurement system is primarily used in HVAC for pressures?

The Imperial system is primarily used in HVAC for measuring pressure, specifically in inches of water column (in. wc) or pounds per square inch (psi). This choice is significant because many HVAC applications and equipment specifications are designed around these units, making it essential for technicians and engineers in the field to be familiar with them. The Imperial system's units are prevalent in the United States, where most residential and light commercial HVAC systems operate, further solidifying its relevance in practice.

While the Metric system and SI units are valued in many scientific and international applications, they do not dominate the HVAC industry in the same way. The decimal system, while useful for numerical representation in various calculations, is not a measurement system for pressure itself. Understanding the use of the Imperial system in HVAC contexts allows professionals to effectively communicate, design, and service systems accurately.