Strange Sounds: Warnings Signs You Need an AC Tune Up


You might be surprised to learn that Americans are spending $6,000 on average to tackle home maintenance issues. That kind of spending can be tough on a household’s efforts to save or stay afloat. That’s why regular preventative maintenance is so crucial to extend the lifespan of your home’s operating systems. 

Is your HVAC system making strange noises? Read on to learn about the warning signs you need an AC tune up!


Hissing noises usually suggest that air is escaping from your air ducts. When a hissing noise is present as the fan runs, an air duct leak typically is the problem. And the source could be anything from a significant gash to a small hole. 

An air conditioning cleaning service can assess your ducts and filters to determine the source of the issue. If you have an unfinished basement, it may be easier to spot the problem. But in other cases, the leak could be hidden behind your walls. 

Hissing also could point to a refrigerant leak. Since refrigerant helps cool the air in your home, you may notice reduced effectiveness in your AC unit’s cooling power during the hottest months if the air refrigerant is the issue.

Too much compressor pressure or problematic heat pump valves also can lead to hissing. With so many potential causes, contact professional HVAC technicians for a proper assessment. 


Bubbling noises often are linked to excess moisture. For example, you could have water leaking or a blocked condensate drain. You’ll hear a bubbling noise with a blocked drain as water slowly works its way through the drain’s limited openings. 

You also could be dealing with a refrigerant leak when you hear a bubbling noise. Ultimately, a leak can lead to a less efficient system. And it can cause your utility bills to soar. 

Keep in mind that refrigerant leaks pose a health threat, too. If exposed to leaking refrigerant, you could endure respiratory problems. It’s best to address this issue right away.


Loose wires or overloaded circuit breakers are among the common causes of a humming noise. If wires aren’t connected properly or your breaker can’t trip, you’ll hear this distinctive sound. You’ll also run the risk of an electrical fire. 

Otherwise, the source of the humming may be the condenser fan motor. If this motor isn’t working well, your entire system could stop. With a routine AC inspection, you can help prevent humming from snowballing into a larger problem. 


When was the last time you checked your outdoor condenser unit for debris? If you’re hearing a rattling noise, it could be because sticks are interfering with the unit. If they’re stuck inside, they’ll create this unpleasant noise. 

Another simple culprit could be loose screws. Even if you try to remove debris or tighten the screws, you may still hear the noise. In that situation, you may have a more severe issue on your hands.

You could have loose components in your AC’s motor. You might have fan blades that aren’t attached properly. Or you might have an electrical contractor that requires repair. 


What sounds like a whirring noise could mean you have fan motor issues. These could be traced to the outdoor unit, but they also might be part of the blower indoors.

Bad wiring connections could cause the fan blades to move more slowly. As a result, you’ll hear the noise and notice reduced effectiveness when you’re trying to stay cool. 

Sometimes whirring can be linked to less severe issues, too. For instance, dead leaves or sticks could be stuck in the fan. Fixing this problem is as simple as cleaning out any debris that’s in the way. 


Buzzing noises can indicate you have problems with your fan. For instance, the blades could be loose or the fan’s motor could be having problems. Or there may be other loose parts within your unit that need to be tightened or replaced.

Buzzing may also indicate a refrigerant leak. Left unaddressed, this problem could cause your unit to stop working entirely.

Buzzing could also suggest compressor problems. In this case, your AC might buzz more loudly when it starts and stops a cycle. 

And finally, buzzing could mean you have electrical problems. Without proper maintenance, you could be risking an electrical fire. You’ll need to have a qualified technician make the correct diagnosis. 


Common AC sounds also include clicking noises. It’s not unusual to hear a clicking noise when your unit turns on and off for a cycle. But when you hear an ongoing clicking noise as your AC cools the air, you’ll want to contact an HVAC technician

You could have a faulty thermostat if your thermostat is older. It might not communicate well with the rest of the unit due to electrical issues. As a result, your unit may turn off and on a lot. 

Other potential causes include aging parts within the AC unit. Old belts or valves may make clicking noises when they start to break down. 

Louder Noises

Be on the lookout for abnormally loud AC sounds. While an air conditioning unit can sound like it’s ready to take flight when it starts up, extra noise can mean there is a problem. 

Shrieking noises that are difficult to tolerate often indicate fan or compressor motor problems. If you start noticing the decibel level increasing, it’s best to take action quickly. Without a functioning compressor, you won’t be able to get cool air in your home. 

Worse yet, your AC unit may be working too hard. You’ll hear a pronounced groaning noise when this is the case. Call your local technicians before things get worse.

Get an AC Tune Up

An AC tune up can help keep your unit running smoothly when you need it most. Listen for hissing, buzzing, or rattling noises that might suggest motor problems or loose connections. And pay attention to hissing or bubbling noises that could indicate leaks. 

When in doubt, seek a professional technician to help keep your system healthy and safe. Contact Advanced Mechanical, Inc. for the most reliable AC repair!

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