Strange AC Noises and What They Could Mean

If you’ve ever been in your house on a hot day and heard a strange noise coming from your AC unit, you’re not alone. Many homeowners experience this issue at some point. Many are not familiar with the inner workings of their AC unit, so strange and unfamiliar sounds can be cause for concern.

While the noises can perplex you, there’s usually a simple explanation for them. This post will go over some of the strangest AC noises you might hear and what they could mean.

Grinding or Squealing

When your air conditioning unit starts to make a grinding or squealing noise, this can signify something seriously wrong — this may be due to a pipe that has broken or become clogged, disrupting the flow of coolant and causing friction between moving parts.

In addition, this kind of noise may indicate that some component within the AC unit has worn down or broken loose, which can also lead to dangerously excessive temperatures and other problems.


A hissing noise coming from your air conditioner is most likely due to a leak in the system — this could result from a cracked pipe or faulty connection, which can allow coolant to escape. In addition, a hissing sound may indicate that too much pressure buildup has happened within the unit, which can also lead to leaks. Other causes of hissing noises include loose fan belts and damaged compressor valves.

Rattling or Chattering

If your air conditioner makes a rattling noise, this could be due to loose hardware or debris that has gotten caught in the unit — this can disrupt the normal operation of the AC unit and cause damage to the fan or other components. In some cases, a rattling noise may also be due to an imbalanced fan blade, which can cause the entire unit to vibrate.

Proper maintenance and regular cleaning can help to prevent rattling noises.


Banging noise coming from your air conditioner is usually indicative of a bigger problem. This noise is often a result of an issue with the compressor, such as a broken piston or connecting rod. Banging noises can also be due to objects caught in the fan blades, resulting in a jarring sound when they hit the housing.


A high-pitched screaming noise coming from your air conditioner is most likely due to restricted airflow — this can result from several different things, such as a dirty air filter, closed vents, or even a bent fan blade. Screaming noises can also arise from low refrigerant levels, which can cause the compressor to overheat.

In some cases, a screaming noise may also indicate that the AC unit is about to fail and needs replacement.


If you’ve ever been plagued by an annoying pulsating noise from your AC unit, you know how irritating it can be. While several different causes could create this problem, one of the most common culprits is a pipe that is not properly sealed.

If air leaks through gaps in the pipe, this will cause your system to circulate more air than normal, resulting in an irregular beating sound as the AC unit tries to regulate its internal pressure.

To fix the pulsating AC issue and restore peace and quiet to your home, simply seal any leaks or gaps around your pipe system using some caulk or other sealant material. With a little care and attention, you’ll be back to enjoying the cool relief of a working AC in no time.

Hopefully, this information will help you keep your home cool and comfortable throughout the year. Steele Bros Heating, Inc., is a leading HVAC company in Colorado, offering a wide range of services to meet all of your heating and cooling needs. If you need AC repair, don’t hesitate to give us a call today. We’ll be happy to help you get your AC unit up and running again.

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Steele Brothers Heating Inc