Air Conditioning Sound FAQs: Which Ones Should You Not Ignore?

Over 87% of US homes have some kind of air-conditioning, and it's a good idea to listen to your air conditioning sounds so you can notice when it makes a noise that's unique or different.

Air conditioning keeps us cool and comfortable. In fact, it is even known to have health benefits such as reduced asthma attacks and a lower risk of dehydration.

As much as they improve our lifestyle, air conditioning systems have their limitations. In fact, even the best air-conditioning units only last 15-20 years. You may find that odd squeaks, unique whistles, and faint hums are all part of your experience after you’ve owned your unit for a while.

Which air conditioning sounds require immediate attention? Let’s take a look.

1. Air Conditioning Screams Loudly

This critical air conditioner sound should not be ignored. If your air-conditioner makes a noise similar to a high-pitched screaming sound, you need to turn the machine off and call a professional immediately.

This sound is likely the result of a refrigeration leak, which can cause permanent damage to your air conditioner. It can also damage your family’s health.

Sudden doses of freon may cause heart palpitations in those disposed to them. It can also cause skin irritations. Your sensor may turn the air conditioner off for you, preventing a potentially hazardous situation.

2. Squealing Sound in Air Conditioning

Sometimes, blower and fan noises cause squeaks to get emitted through your air conditioning system. Your blower wheel may also emit squealing sounds while it is starting up. You will need to use a little discretion to determine if the noise is a normal part of a startup, or something new.

3. Air Conditioning Makes Loud Clicks

Your air conditioner may click during start-up. This may just be your thermostat communicating with your unit. Constant clicking, however, could signal an electrical problem.

There could also be something damaging your blower fan. In a central air conditioning system, the blower motor pushes air through the system at varying speeds. A properly functioning blower is critical for maintaining comfortable temperatures throughout your home.

Blower motors can get damaged from being worn out, or from fan cage obstruction. Routine maintenance can prevent problems before they start.

4. Banging Noise inside A/C Unit

A banging noise may indicate that something got loose inside your air conditioning system. Often, it is the crankshaft connecting to the rod inside your compressor.

In a typical air-conditioning system, the compressor’s job is to circulate the refrigerant necessary to exchange heat between the indoor and outdoor units. It also applies energy to the refrigerant.

A motor powers the compressor with a cylinder and piston. It raises the refrigerant’s temperature so that it turns into a high-pressure gas.

The crankshaft is the main shaft inside the compressor. It connects to the rod, which in turn connects to the compressor at the other end. The connecting rod is usually made up of carbon steel forging. When it is loose, you will hear it.

The compressor is a major part of the air conditioning unit. The compressor gets subject to grime and dust contamination, as well as wear and tear. Any coolant leak can cause damage to the compressor, but if your unit is still under warranty, you will only have to pay for labor.

Banging can also indicate that your outdoor unit is hitting something. It may be close to an obstruction that shouldn’t be there.

Your air conditioner fan control’s your unit’s blower. It helps distribute air throughout your home. You may also hear banging when your air conditioner’s fan comes loose from its mounts. It could wobble and hit your compressor’s protective cage.

You may need to replace your compressor entirely. It is critical, however, to call a professional if you hear banging.

5. Air Conditioning Hums When Running

While light humming may simply indicate that your unit is “humming along,” loud humming indicates that there may be parts loose within your unit.

Loose parts combined with refrigerant piping can cause vibration.

The refrigerant piping creates a pressure drop that reduces the pressure of the refrigerant to that of the air conditioner. At this low pressure, the liquid refrigerant can get cooled to the desired temperature.

If the refrigerant piping continues to get irritated, serious issues could develop later on. You need to contact a professional right away.

If your compressor hums and won’t start, you may have a problem with your motor or loose wiring. Your motor removes warm air from the air conditioner’s interior and blows cold air through the vents. Any motor issues that are not immediately serviced can lead to your system’s inability to function.

If your air conditioner gets worn down, wires can get dislodged and lose contact with the major power source. This can disrupt airflow and cause malfunctioning. Exposed wires can also become fire hazards.

Any loud humming needs to get immediately checked out by a professional.

6. Air Conditioning Sounds Like It's Buzzing

Can you hear buzzing as a new air conditioning sound? If it's coming from inside your A/C, it could indicate loose parts or debris inside or outside of your unit. It may also tell you that your fan blades are out of balance.

The blades on your fan are metal and can bend and break, especially if you have an outdoor unit. If a blade gets loose, it can hit other air conditioner components as it spins.

Loose fan blades can be hazardous to your entire air conditioner system, and they should get replaced as soon as they get discovered.

A buzzing sound could also indicate loose copper lines outside or inside your unit. Copper refrigerant lines carry refrigerant between the condensing unit and the evaporator coil.

Your condenser coil could also need cleaning. The condenser coil is located outdoors, where the heat is removed from the refrigerant.

Buzzing could indicate that your blower got out of balance. You could also have refrigerant leaks, resulting in a freeze-up.

Your air filter may also need to be changed. The filter prevents dirt and grime from building up on your air conditioning coils. It also improves indoor air quality.

Buzzing might also mean loose wires, a failing motor, or a broken capacitator.

The capacitors are small cylindrical units that store energy. They send jolts to keep the motor running. If a capacitator gets chipped, it may begin buzzing when you start up your unit.

7. High-Pitched Whistles from A/C System

If your air conditioner emits a high-pitched whistle, turn it off right away.

A whistling air conditioner tells you that your return vent is starved for air. This usually results from some type of blockage, which produces higher pressure and air velocity inside the vent.

One common cause for this blockage is a dirty air filter. It could also get caused by closed or blocked supply vents. If you know where these vents are, you can open them yourself.

Whistling also gets caused by shut or closed dampers. These are metal valves that close to prevent air from flowing into other parts of your home. If you can, open them to make sure they get in line with the ductwork.

You could also have debris or other objects lodged in your ducts. If you feel comfortable, try to dislodge them. If you don’t, call a professional right away.

Too many closed doors in your home could also be the culprit. These block the path for air to go back to the return vent. The restricted airflow forces the blower to work harder, leading to the whistling sound.

Keep more doors in your home open for a better, less restricted airflow.

8. Air Conditioning Gurgles When On

A gurgling noise means that your drain line is clogged or cracked. The drain line is the exit unit for air collected by the evaporator coil as air passes over it. It removes humidity from the air and converts it into water.

If you feel comfortable, turn off the unit and inspect the drain line. Otherwise, contact a professional.

9. Chattering or Rattling Sounds inside A/C

Rattling could indicate that your unit is starting to deteriorate. Parts could be loosening inside your systems, such as a fan blade, cover plate, or screw.

You could also have debris, such as twigs and leaves, in your system. Before calling a professional, try checking for loose screws, cleaning the condenser coils, and changing the indoor filter.

10. Air Conditioning Hisses Quietly

A hissing noise indicates a refrigeration leak in either your line or coil. This can cause inefficient cooling. A leak can be dangerous to your system and the health of those in your home.

A hissing noise should get inspected immediately by a technician.

Air Conditioning Noise

Even the newest systems emit musical air conditioning sounds occasionally. If, however, you hear unusual screaming, buzzing, or banging coming from your air conditioner, it is time to call a qualified professional. They can help you eliminate the problem and restore your home to comfort.

For more information, contact us today.