10 Different Types of AC Noise And What Causes Them

Learn about various types of AC noise and their causes. Trust Sandium for expert advice on minimizing HVAC noise and finding the best low-noise air conditioner.

Updated on Oct 23, 2023
5 min read
10 Different Types of AC Noise And What Causes Them

There is nothing more comfortable than having air conditioning in your Bay Area home, especially on a hot summers’ day. But, that noise coming from the AC unit can quickly turn your relaxation into stress. It is normal for a bit of humming to come from the motor. In fact, humming is quite normal in older systems. However, loud strange noises could signal that there is something seriously wrong with your air conditioner.

1. Buzzing

Loud buzzing noises coming from your air conditioner could signal trouble. It is almost always because of electrical problems. In most cases, the contactors or relays develop a problem. You should turn off the air conditioner unit and call your local HVAC professional ASAP to get the system fixed.

2. Humming

Air conditioner fans usually make a loud humming sound. Generally, all the fan needs is a good cleaning for the sound to fix itself. However, in some instances, the humming may be caused by worn out components, bent fan blades or a failing fan motor.

3. Banging

Banging can occur in an air conditioning unit for several reasons. The banging may be because of an off-balance indoor blower. If not that, a damaged or loose connecting rod, piston pin, or crankshaft may also cause the banging sound by clanking around within the compressor.

4. Clicking

Clicking sounds are normal when your air conditioner starts up or shuts down. However, it is a sign of trouble when the clicking sound continuously emanates from the ACs electrical parts. This can be because the thermostat needs replacement or the air conditioner has faulty controls.

5. Clanking

An unbalanced indoor blower or an outdoor fan could cause metallic clanking. The sound could also be because of an out of balance or loose compressor. You may require a new compressor in this instance.

6. Rattling

Rattling noises in an air conditioner are usually because of pebbles or twigs caught in the outside component. It could also be because of screws, bolts, and fan that have become loose over time.

7. Squealing

Worn out belt or blower fan motor bearings is usually the most common reason for high pitched squealing to come from your air conditioner’s indoor unit. Motor malfunction in your compressor or fan could be another reason.

8. Hissing

Hissing is a cause of concern if it starts when you switch on the air conditioner. This could be because of buildup of high pressure in the compressor and is very dangerous. You should turn off the air conditioner immediately and call a repair person.

9. Whistling

Try replacing or cleaning the air filters when the cooling system starts to produce a whistling sound. Clogged air filters can cause whistling noises. It is possible for your HVAC ducts to be at fault as well. The ducts may not be of a compatible size as the air conditioning system. Or, the ductwork has leaks and cracks.

10. Bubbling

Bubbling sounds from air conditioners sound a lot like gurgling liquid. In fact, bubbling is usually because of condensate gurgling while passing through the drain line. Bubbling may also be caused because of a refrigerant leak. You should have this checked by a professional technician as soon as possible.

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