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Serving Northern California Since 1946

Serving Northern California Since 1946


DeHart Plumbing, Heating, and Air Inc. Blog

What Should Your Air Conditioner Sound Like When It’s Running Properly?


A pretty popular topic in regards to “AC repair” blogs is going to be the sounds you shouldn’t hear coming from your air conditioner–noises that typically indicate that something is wrong and might require repairs or at the very least some troubleshooting. Even in our own blog, we’ve had posts about these warning sounds.

What’s not discussed enough, however, is what your air conditioner should sound like when it’s running exactly as it is supposed to. There is no such thing as a completely silent air conditioner. While technology is making them quieter and quieter, there are some sounds you’ll still be able to hear, and in fact should hear when your air conditioner is operating as it should be. Read on to learn what these noises are.

“Humming” Coming from the Compressor

The most important sound you’ll ever hear from your air conditioning system that signals it’s operating exactly as it should is the hum of the compressor inside the condenser cabinet.

When you hear this sound, it means that the air conditioner has started a cooling cycle. The system has received a signal from the thermostat that the interior of your home requires cooling, and the compressor’s motor starts so it can put the liquid refrigerant under pressure and change it into a hot gas, so it will then circulate to carry out the heat exchange processor.

Once the compressor turns on, you’ll feel cool air coming from the vents in the various rooms of your home. If you hear the compressor running and don’t feel cool air coming through or notice that the air isn’t very powerful, you may have a problem with the blower fan.

“Spinning” of the Fan

This is the primary sound you’ll hear your air conditioning system make from the inside of your property. It’s the blower fan working to push air through the air conditioner and through the air ducts. It should be a gentle and steady noise–some people even enjoy the sound of this “brown noise.”

“Dripping” of Water

This is a noise you may here from the indoor components of your air conditioner. It isn’t constant. However, it is something that you may hear at periodic intervals. If you have ever watched a window AC operate from the outside, you may have noticed water dripping from it. This is the same condensate moisture you hear dripping in your central air conditioner.

And no, it’s not dripping into or onto your property. At least, it shouldn’t be. Instead, it’s dripping into the condensate drain pan and a condensate drain, where it makes its way out to a carefully placed drain so the water leaves your property.

“Rattling” of the Ductwork

This shouldn’t be a heavy or severe rattling, but rather more like a “crinkling” sound as the temperature of the air changes the temperature of the ductwork it’s traveling through, and the metal ducts expand and contract as a result. As long as this sound doesn’t change, nor do you notice performance issues in combination with this sound, this is a normal noise to hear during the cooling process.

DeHart Plumbing, Heating, and Air Inc. is your trusted local resource for quality AC repair in Tracy, CA. Contact us today!

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