What is the term for a compartment or chamber connected to one or more ducts as part of the air distribution system?

The term that best describes a compartment or chamber connected to one or more ducts as part of the air distribution system is "plenum." A plenum serves as a central distribution point for air in heating, ventilation, and air conditioning (HVAC) systems. It allows for the mixing of air, ensuring that it is evenly distributed to various parts of the building. The design of the plenum can significantly influence the efficiency and performance of the HVAC system.

In contrast, a diffuser is a device that distributes air flow from a duct into a room or space but does not itself connect to multiple ducts. The return refers to the air flow back to the air handling unit or the central HVAC system for reconditioning, while the term chamber is more generic and does not specifically refer to the role of air distribution within HVAC systems. By understanding the role of a plenum, its significance in air distribution becomes clearer, as it plays a crucial part in maintaining indoor air quality and comfort.