The answer to 'why is my ductwork making loud noise' is that there are several common causes, including loose fittings, obstructed airflow, and duct vibration. Loud noises coming from your ductwork can indicate an underlying issue that requires attention.
Loose fittings or connections in the ductwork can allow air to escape, creating a whistling or rattling sound. Obstructions like debris or damage in the ducts can also restrict airflow and lead to noises. Additionally, duct vibration caused by high airflow velocities or poor installation can result in banging or rumbling sounds.