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3 Strange Air Conditioner Noises

3 Strange Air Conditioner Noises

Hearing your air conditioner emit a strange noise is a cause for concern. Even if the problem is nothing serious, it’s still worth having an HVAC contractor inspect the unit for signs of potential damage. Different types of sounds indicate different issues, and your technician may be able to resolve them quite easily. 

Why Is Your Air Conditioner Making Strange Sounds?

1. Rattling

There are several problems that could cause the system to rattle. One of the simplest to fix is the presence of debris, like twigs, in the outdoor unit. If you suspect this is the case, turn the power to the unit off and gently extract the debris. Sometimes, the sound may seem more central, which may indicate a loose screw or fan. The more it rattles, the more likely the part will eventually disconnect and cause more substantial damage to the air conditioner.

2. Hissing

If you hear a hissing noise from the walls, then it’s likely due to leaking air ducts. This can occur if there’s a tear somewhere in the system or the ducts aren’t properly sealed. You may not hear the hissing noise before you notice other symptoms, such as elevated energy bills because the air conditioner is working harder than usual to meet your desired temperature or hot and cold areas throughout the house. Sometimes, lighter hissing is indicative of a poorly positioned air filter that isn’t sealed properly. This forces air to move through the surrounding gaps instead of directly through the filter; adjusting it should help.

3. Screeching

You might notice a screeching sound after turning on the air conditioner. That may be because the motor bearing or belt is in danger of failing. These parts tend to squeal or screech loudly if they’re in near states of disrepair. Your HVAC repair technician can replace the part before it causes more significant damage that prevents the unit from cooling your home effectively. In some cases, all you need is a little lubricant to moisten the belt or motor bearing, which is a quick fix.


Residential and commercial air conditioners are designed to run efficiently, but when something goes wrong, you can trust the team at Ron Hammes Refrigeration in La Crosse, WI, to help. These qualified HVAC technicians have extensive experience handling everything from basic maintenance to heating and cooling repairs. Visit them online to learn more about their services, or give them a call at (608) 788-3110 to schedule an appointment.

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