Causes And Solutions Of Typical Air Conditioner Noises

June 19, 2020


Today’s high-efficiency air conditioners are quieter than ever – they contain sound-dampening technology and two-stage compressors to maintain noise levels below 55 decibels. However, if you hear any noise coming from your AC unit during routine operation, don’t take it lightly, as this could mean that your air conditioner requires an upgrade or repair.

Ignoring the unusual sounds coming out of your AC unit can turn minor issues into major problems. These mysterious noises could mean anything from requiring a simple AC tune-up to costly repairs, or in the worst case, replacing the entire unit. It’s best to contact a well-known air conditioning repair expert at the earliest to determine the causes of these noises and resolve such issues immediately.

Let’s discuss some of the everyday noises that could be coming from your air conditioner, along with their causes and solutions:


When you hear a hissing sound coming from your central air conditioning system, it may be due to a possible leak in your AC unit’s refrigerant line. Refrigerant is a substance that absorbs heat from the indoor air and carries it to the outdoor unit to dump it into the outside atmosphere.

If there’s a leak in your air conditioner’s refrigerant line, it can give a hissing noise. Other possible reasons for this strange sound may include the presence of ice on your refrigerant lines, warmer air coming out of your unit’s supply vents, and increased energy bills.

When you hear a hissing noise coming from your AC unit, reach out to a nearby HVAC contractor who can repair the leak and recharge your refrigerant.


A banging noise coming from your air conditioning system can be caused by different factors, including:

  • Loose Fan Mount: With time, mounts holding the blower wheel can become loose, causing your fan to hit your AC unit’s casing, resulting in a banging noise. In case of a loose fan mount, reach out to a nearby air conditioner maintenance professional to replace or repair this component immediately
  • Air Filter Issue: The air filter is usually placed in front of return ducts – these ducts, when placed on the ceiling, may suck the air filter up as well when pulling air inside. When these ducts stop pulling air in, the air filter falls back down, resulting in a banging noise. If your AC unit’s air filter gets sucked up against the top of the duct box, you may have a dirty air filter, that needs replacing
  • Loose Fan: The outdoor unit’s fan can also get loose, hit its casing, resulting in a banging noise. It’s best to contact a professional AC repair service to fix this issue as soon as possible
  • Loose Refrigerant Pump: When the springs that hold your AC unit’s refrigerant pump in place get damaged, the refrigerant pump may hit the side of the compressor, resulting in a banging noise. Contact an air conditioning expert for help in such cases


A clicking noise coming from your AC unit usually indicates that the system is trying to turn on, but it’s not able to do so for some reason. This issue generally arises due to a thermostat malfunction, faulty relay, wiring problem, dead capacitor, or broken contactor.

Reach out to an AC unit repair professional immediately for assistance when you hear a clicking noise coming out of your AC system.


A buzzing sound coming out of your air conditioning unit usually means that there’s some electrical issue with it. Some of the reasons for this include malfunctioning electrical connection, contactor, AC circuit breakers, and condenser fan motor.

Some non-electrical causes of buzzing noise may include damaged compressor isolation feet, frozen AC, and other loose parts. Any repairs or replacements necessary to overcome the buzzing sound will require the assistance of air conditioning professionals.


A frayed or misaligned fan belt can be a possible reason for squealing sounds coming from your AC unit. The fan belt connecting fan and motor can wear out, resulting in squealing or screeching noises. In other cases, the belt could also have got misaligned, giving rise to a squealing noise.

When you hear this type of noise coming from your air conditioner, contact an air conditioning mechanic who can realign or replace your AC unit’s fan belt.

Nor-Can Heating & Air is a professional HVAC contractor that provides the best quality air conditioner installation and maintenance services to its clients in Edmonton, Alberta. Visit our website to learn more about our expert services or contact us for customized care.


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