What could cause unusual noises in an HVAC system?

Unusual noises in an HVAC system can often be attributed to loose components or airflow issues. When parts of the system, such as ducts, screws, or panels, become loose, they can vibrate or rattle during operation, leading to disruptive sounds. Additionally, if there are airflow restrictions due to blockages or improper duct sizing, the system may struggle to operate effectively, resulting in noises such as whistling or banging.

In contrast, faulty insulation materials do not typically generate noise themselves; rather, they might lead to inefficiencies or temperature fluctuations. A properly functioning compressor is designed to operate quietly during normal conditions, so it would typically not be a source of unusual sounds. Finally, while a recent cleaning of the ducts generally helps maintain system efficiency, it is unlikely to be the source of unusual noises unless some component was accidentally disturbed or left loose during the cleaning process.