What is a common cause of noise in HVAC systems?

Noise in HVAC systems can often originate from loose parts or component wear. Over time, the vibration and movement of various components can lead to screws, bolts, or other fasteners becoming loose. This results in rattling or banging sounds as the parts move against each other or as air flows through the system.

Additionally, components that are worn out, such as bearings in motors or fans, can create unusual sounds as they no longer operate smoothly. Such noises are indicative of the physical deterioration of parts, leading to operational inefficiencies and potentially more significant damage if not addressed.

In contrast, low refrigerant levels might affect the efficiency of the system but are not typically associated with noise. Similarly, while old designs may not perform as well, they don't inherently cause noise unless specific components are failing. Improper installation settings may lead to operational issues or inefficient performance but do not directly correlate with noise generation from the system.