Why Your Air Conditioner Makes Strange Noises

Your air conditioner should have a steady-flowing sound at a reasonable level. Most units are designed to keep noise levels at a minimum. When you notice a change in the type or volume of sound, you may have a problem. Unusual noises are a good sign that something might be wrong with your unit. Here are some sounds your air conditioner shouldn't make unless you need repairs.


Rattling and banging are signs that something is loose inside the unit. The loose object could be a broken part or a foreign object. Check the outside of your unit to see if any plants or debris made their way into the casing. The fans inside your unit are also a common cause of many rattling sounds. Often, their bearings wear down, and they can become loose, move out of place, and slap against other parts.


Screeching from an outdoor central air unit is a classic sign of a bad or loose fan. Screeching in an indoor unit is often due to a worn blower motor bearing. In some cases, a technician can lubricate the blower motor bearing, and it will be OK. You may also have a bad compressor, especially if the screeching goes away after the unit has been on for a while. With that last item, you may also experience warm air coming from the vents.


Some popping signs are normal, especially in central systems with air ducts. You may hear some popping noises after running the unit for a long period. It is not a problem unless it's very loud or continues long after you shut off or turn on the unit. However, consider having your ducts checked out. You could have broken joints that will leak out the cold air.


Buzzing may indicate potentially serious electrical problems. When you turn on the unit, nothing may happen except for a loud buzz. It could indicate a bad breaker or a loose wire. Sometimes, a mechanical issue like a stuck or frozen fan can cause a buzzing sound. Either way, don't try to use your unit until a professional takes a look at it.

Other Possible Reasons

Sometimes, air conditioners can make noise if they don't have any sound dampening around the unit. This problem is easily rectified. You can even get a sound dampening blanket for your outdoor unit. If your air conditioning unit sounds unusually loud, contact a technician for help. They can determine whether you need repairs, replacement, or a simple fix.

Reach out to a professional if you need AC repair services.