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What Does That Weird AC Noise Mean?

woman-covering-her-earsWith the way technology is advancing, there may be a time in the not too far off future that air conditioners will have some component that allows them to self-diagnose when something is wrong, and alert us via an app on our own. It’s really not too far-fetched of an idea when you think about it. But alas, it’s simply not a reality yet.

In the meantime, we have to rely on our senses to detect when something is amiss with our cooling systems. If you feel a drop in cooling power, or see an unexplained spike in your energy bills, this can indicate a problem. Or you may see that your circuit breakers for the system’s indoor and outdoor units are constantly tripping.

Another very common indicator that something is wrong with an air conditioner is the presence of strange noises. And by strange noises, we mean anything out of the ordinary humming or faint clicking you hear as your cooling system operates. So, what sort of noises should you listen for, and what do they mean?

Hissing or Bubbling

Depending on if it’s in gas form or liquid form, you may hear a hissing or bubbling noise if you have a refrigerant leak.

Refrigerant, which you may have heard referred to as Freon at some point, is the fluid that enables the entire cooling process for your air conditioner. Without enough refrigerant, your AC system will begin experiencing a host of problems, not excluding full system breakdown.

There’s a fairly common misconception among many homeowners that refrigerant is something that “runs out” naturally, like gasoline from a car. But this isn’t the case. Ideally, refrigerant is recycled through the system throughout the entire lifespan of that system. So if you hear hissing or bubbling, or notice a drop in cooling power or ice development on the coils, it could definitely be the sign of a refrigerant leak—and it’s time to give us a call.


We’re going to start this one off by saying that some clicking is normal. When your system starts up and cycles down, faint clicking indicates that the system is doing its job. However, if you hear clicking the whole time the compressor is running, you might be facing a serious AC issue.

On that note, if you notice your air conditioner is “hard-starting,” or rather, it’s struggling to come on and then booming once it does, it’s a sign that the system is having a hard time powering the compressor and requires a professional inspection.


This is perhaps one of the most alarming sounds a person can hear coming from their air conditioner, and certainly should never be ignored. Fortunately, it doesn’t usually indicate a major problem, but one that should be remedied right away.

Clanging usually means you have a loose fan belt or a bent air handler fan blade. This is most likely to occur in an aging air conditioner. However, whether you hear it in an aging system or a brand new one you should give our pros a call!

These are just a few sounds you might hear coming from your air conditioner that signal a problem. Generally speaking, anything outside the normal operational sounds you typically hear is cause for concern.

Contact Comfort Flow Heating today for your air conditioning service in Salem, OR.

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