The answer to 'why is my air handler making loud noise' is that there are several common causes, including worn bearings, a loose fan, or a problem with the blower motor. Loud noises coming from the air handler can indicate a mechanical issue that requires attention.
Some of the most common symptoms of a noisy air handler include grinding, squealing, or rattling sounds. These noises can be caused by problems with the blower fan, motor bearings, or other moving components. If the noise is accompanied by reduced airflow or strange smells, it's a sign that the air handler needs professional inspection and repair.