8 Common HVAC Noises Explained And When To Call An Air Conditioning Service | Earlville, IL

8 Common HVAC Noises Explained And When To Call An Air Conditioning Service | Earlville, IL

Modern air conditioners are quieter than ever, thanks to technological innovations that have made it possible to minimize operation noises that would inconvenience Earlville, IL homeowners. However, your HVAC may produce more than the quiet background hum as it ages. The unwelcome sounds often signify that it’s time for a repair. Admittedly, keeping up with air conditioning service is an excellent way to avoid system breakdowns and unsettling sounds. This post outlines common HVAC noises, potential causes, and a few tips for putting them to rest.


A loud banging noise from your HVAC can result from different problems. If it comes from the furnace, it can signal ignition issues causing a gas buildup in the chamber. It could also be related to the furnace blower or motor, signaling a loose or broken component.

Loud banging noise from the outdoor unit could indicate a compressor problem, such as a loose piston, old or broken dampers, and expanding ducts.

The best thing you can do after hearing banging noises from your HVAC is to contact an air conditioning service immediately. Some of the solutions our technicians will implement include cleaning fan blades, motor lubrication, cleaning condenser fins, and tightening loose components, depending on the findings of our diagnostics inspection.


A buzzing sound from the HVAC is usually a sign of electrical problems due to wear and tear. Some electrical components that cause this sound include the contact relay switch, circuit breakers, condenser fan motor, and electrical connections at any component. Buzzing can also result from a frozen AC unit, condenser motor issue, isolation foot damage, compressor malfunction, and loose AC parts.

Whatever the underlying cause, a buzzing HVAC is not something to take for granted. Hiring an air conditioning service is the best way to restore your system’s function and improve overall performance, efficiency, and longevity. As you wait for our team to arrive, turn off the HVAC to prevent further damage.

Squealing and Screeching

A squealing or screeching sound from the air conditioner can indicate the wear and tear of moving components. For instance, the motor bearings may be damaged and cause the motor to be off-center. The belt may also need replacing. Another reason for squealing and screeching noises from your HVAC is the motor needs lubrication.

Regular maintenance where an air conditioning service repairs and replaces the motor bearings and belt before they stop working can prevent system breakdown. Our technicians can also lubricate the compressor motor to prevent screeching noises.

Frequent Clicking

Clicking is a welcome sound when the weather turns cold and you turn on the heat because it means your system is powering up. However, constant clicking is a sign that something might be wrong. HVAC clicking noises can suggest system relay disruption. It can also mean that one of the AC fan blades is bent, broken, or damaged.

If the HVAC clicks but won’t power up, there could be a problem with the controls – specifically the thermostat, control board, or capacitor. If the clicking continues until you manually turn off the unit, some other part may not be doing its job.

Whatever the issue, it’ll only get worse without proper mitigation. Contact an air conditioning service immediately for professional troubleshooting and repair.


Hissing HVAC sounds are rare but incredibly concerning when they occur. The most likely reason for hissing sounds from the HVAC is the ductwork leaking air.

This can lead to a steep increase in energy costs as your system works overtime to compensate for the air loss, which can cause more HVAC issues. Leaking ductwork can cause the air filter to clog faster, create hot and cold spots in the house, and compromise indoor air quality.

The hissing sound from the compressor could signify a refrigerant leak or dangerously high internal pressure. If the sound is coming from the furnace, it could be due to a leak.

All these issues are severe and should be handled by a professional. Disconnect your AC immediately if you hear hissing sounds and call an air conditioning service for proper diagnosis and repair.


Knocking sounds from the outdoor condenser unit indicate a loose or broken piston pin, crankshaft, support springs, or screws. Depending on the severity of the situation, mitigation may be as simple as fastening the loose components or as complex as compressor replacement.

A clogged filter strains the blower motor, causing knocking sounds. Cleaning or replacing the air filter eliminates the sounds and optimizes energy efficiency.

Other reasons for knocking sounds include trapped debris in the outdoor unit, fan problems, an unbalanced motor blower, improper system installation, a failing compressor, and undersized ductwork.

Contact an air conditioning service in Earlville, IL, immediately to get your system professionally diagnosed and prevent minor issues from becoming major emergency problems.


There are a variety of issues associated with popping HVAC sounds. In many cases, the popping sounds occur because ice forms in the unit. Ice forms when the temperature is too low or the system doesn’t drain condensate properly.

Popping sounds can occur after heavy rains because water floods the unit or due to mechanical or electrical problems. Loose bolts, screws, or joints can also cause these sounds. When you hear popping sounds, the best cause of action is to shut down the HVAC and call an air conditioning service for proper diagnostics and repair.

Say Goodbye to HVAC Noises

The HVAC system plays a vital role in the comfort of your Earlville, IL home, especially when the temperatures are extreme. But it consists of dozens of components that wear and tear with time, resulting in weird noises. Regular maintenance is essential to keeping those noises at bay while optimizing performance.

If you haven’t had your annual HVAC checkup, contact the Just In Time air conditioning service for an inspection and tune-up.

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