Your HVAC system shouldn’t be causing any of the noises you hear in your home.
You shouldn’t hear HVAC systems or air ducts.
So, if you suddenly hear a noise that wasn’t there before, it’s not something to ignore. Your air vents may be whistling due to blocked airflow. Check that your vents are open and nothing is blocking them. Take immediate action if you hear dripping water from your air conditioner. The system should be turned off immediately and inspected by an HVAC technician. It may be that something is loose in your air conditioner if you hear rattling. Make sure there is no loose debris hitting the condenser fan on the outdoor unit. There could be a loose piece in the system or a faulty compressor if no debris is visible. Noises from inside could be coming from the air handler. A loose screw or wobbly supply air fan is likely to cause this. A professional HVAC technician should address these problems immediately to prevent further damage. It could be a loose fan belt or worn bearing, or it could be the more serious sound of a dying compressor. The most common cause of squeaking is a belt or bearing. Your comfort system may be low on refrigerant if it makes gurgling or bubbling noises. Your comfort system will likely struggle to cool your home if it’s low on refrigerant, as well as making loud noises. Leaking refrigerant is bad for the environment and for your health. Call an HVAC contractor right away.