A cracking or popping noise in your HVAC system is because of humidity buildup that can result in icing. This buildup and ice cracking sound in AC are a problem that results in your AC not performing to the fullest.

Before we start, please note:

If your AC has a popping sound or issues working correctly, it’s best to turn it off and switch the main power off. Try closing the main power to the unit (via the circuit breaker) and wait for an HVAC professional to inspect it.

Rare or sporadic noises might not be a big deal.

The first question you should ask is about the frequency of the noise. Usually, the noises occur from time to time which isn’t as big an issue as you might think.

For example, hearing a popping sound shortly after the AC kicks on is normal. It could be as simple as the duct expanding due to temperature. This is especially true if the noise is metallic and echoey as if someone were tapping on a large sheet of metal.

Most ducts consist of thin, flexible metal. Turning off the HVAC system can cause warm air to make its way into ducts, slightly expanding them.

The metal then rapidly cools and contracts as cold air from the air conditioner passes through. According to Air Duct Sanitizing Lawrenceville services, there will be a brief series of creaking or cracking noises followed by a loud pop.

This thermal expansion type is generally harmless even if the noises are infrequent; no need to worry. Especially if the AC performance remains satisfactory, you should inform your AC technician the next time they come for a regular inspection visit. They can inspect your unit to ensure there isn’t a more severe issue.

If this happens throughout the season, it could mean that your ducts are leaking air or not correctly configured. If this is the case, having them repaired may stop not only the noise but also reduce your energy bills.

Continuous cracking or popping noises can be dangerous.

Unfortunately, a cracking or popping noise can cause a more severe problem that requires your attention. There are usually one of two reasons for noise regularly:

The unit is starting to ice up.

Forming of ice may result in cracking and popping noises from inside the unit. This can occur if the temperature is set too low or if the drain is not properly functioning. AC units have a sensor that detects ice formation and turns it off to thaw it out. Set your thermostat to a higher temperature to see if this noise happens again. If the noises stop, you may be fine. However, if they return after a short period of time, it means a problem with the unit itself. You may call a local Mold Air Duct Cleaning Lawrenceville for inspection as they’re professionals who know the unit better.


You can also check to see if it’s draining correctly on some units. Simply remove the removable drain pan to inspect the drain. If the pan is full of water and a clogged drain, clean it out so that the water flows out normally. This will prevent a buildup of cold water, which could cause the unit to freeze. Always refer to your owner’s manual for instructions, and never attempt to open the compressor unit on your own.

There is water in the unit.

If water gets into the sensitive parts of your air conditioner, it can cause serious performance problems. Not only that, it can damage your unit as well, which is bad. If your nose began shortly after a heavy rainstorm, this is the most likely cause.


Air Duct Sanitizingservices normally start by turning off the unit and main power line before proceeding. You can do the same, and once it’s off, visually inspects the outdoor unit for signs of debris or anything else. It could be something that could be blocking the unit and preventing water from draining. Again, if there is a drain pan nearby, check to see if it is draining properly. Also, clean any debris from the unit’s exterior. Try to let professionals handle it and do not open the unit itself.

Unless there’s water in the HVAC unit, it can reach more sensitive components. Although they’re usually sealed from rain, water damage can still occur.

Other Noises from HVAC Unit

Sometimes, the ice-cracking sound in AC can cause the same type of noise. So it’s essential to know what the various noises of an HVAC unit might mean. Here are some other noises and their likely reason why it happens:

AC Making a Banging or Rattling Noise

In most cases, aggressive banging is most likely a condenser problem, but this is not always. To remove the stuck items, remove the condenser cover. Consider hiring a professional if you are having difficulty operating your HVAC unit.

• Tightening Screws

• Faulty Fan Motor or Compressor

AC Noises Screeching and Squealing

Is your air conditioner making a high-pitched screeching or squealing sound? It could be because of:

• Defective Fan Motor Bearings

• A worn out or a broken belt

• Excessive pressure in the compressor unit

AC Creating a Pulsating Sound

If your air conditioner is making slow pulsating noises, you may not need to worry. If the noise is loud and rhythmic, it indicates a problem.

• Loose Fan Blade or Coil

• Pulsating AC Plastic Base

• Refrigerant Lines Making Contact with the AC Walls

AC Producing a Hissing Sound

Have you ever had the impression that a snake has made a home inside your air conditioner because you keep hearing loud hissing noises? According to Mold cleaning services, here are some of the potential causes and what you can do about them:

• Refrigerant Leak

• Compressor Valve Leak

• High Compressor Pressure

Your HVAC Unit Is Making Clicking Noises

A clicking sound at the beginning and end of a cooling cycle is acceptable. What isn’t normal is a constant clicking sound. It’s not the Predator, but here are some common culprits of the clicking noises:

• AC Fan Obstruction

• Capacitor Loss of Charge

• Electrical Signal Fault

• Loose AC Fan

• Malfunctioning Thermostat

The AC is making a whistling sound.

Is your air conditioner making a whistle-like noise? This noise may not be as loud as the others, but it does indicate that something is wrong with the air conditioner. Here are some possible explanations:

• AC Duct Leak

• AC AirFlow Obstruction

Humming Noise from the Air Conditioner

Usually, your AC motor humming isn’t unusual. However, it becomes concerning if its volume increases. If it’s not your roommate humming, your AC may have one of the following issues:

• The lubricant level is too low

• If the contactor fails

• The fin coils are bent

Obnoxious Buzzing Noise from an Air Conditioner

Is your air conditioner making obnoxious buzzing sounds? Not that there isn’t a bee stuck there, it’s more likely one of these issues:

• Inadequate Compressor Performance

• Loose Parts

• Capacitor Failure

• Faulty Motor

• Failed Contactor

• Loose wires

• Freezing of AC components

AC Unit Making a Grinding Noise

A grinding noise coming from your air conditioner could be caused by a compressor or motor problem. Air Duct Sanitizingstates that it’s because of:

• Compressor failure

• Motor failure

AC that is gurgling and bubbling Noise

Bubbling and gurgling sounds are easily confused and could indicate the same issue. Here’s why they might be happening:

• Inadequate Refrigerant Line Sealing

• Excess Moisture in Your AC

Your AC is making a dripping sound.

An air conditioner that makes a dripping sound is cause for concern. Do not panic; it could be due to excess moisture falling into the drip pan. This is completely normal. However, if the dripping sound is caused by excessive condensation, it may be a cause for concern.

• Excessive Condensation

• AC Coils Freezing


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