Strange AC Noises and What They Mean

When your air conditioner is on, the last thing you want to hear is the system itself. AC systems have become increasingly quieter over the years, so it's concerning when you hear strange noises coming from your AC unit. Certain noises are normal, even expected. When you turn on your air conditioner for the first time after a season of dormancy, it's normal to hear some rattling as the system warms up; what's not normal is if those noises last. 

We're sharing strange AC noises and what they mean for the care and maintenance of your HVAC system.

Banging

If you hear a banging sound coming from your air conditioning system, it is likely that something is broken. Banging sounds can be produced by a connecting rod, piston pin, or crankshaft that is broken or completely loose. Another reason you may hear banging from your AC unit is if a stick or other debris has become lodged in the condenser. When you hear banging, it's best to turn off the air conditioner. Contact an HVAC professional to diagnose and repair the problem.Screaming or Screeching


We've all heard it: a mechanical wailing from your HVAC system. It is not a pleasant AC noise and should be investigated as soon as possible. When you hear a screaming noise coming from your air conditioner, it could mean one of several things. It could indicate that you have a refrigerant leak in your system. If this is the case, turn off your air conditioner immediately because a leak will cause damage to your AC system and may endanger you or your family members. Another cause of a screaming AC could be a buildup of pressure in the system. The compressor may make a screaming or screeching noise as a result of this buildup. If you hear this, immediately turn off the system and contact an HVAC professional.

Clicking

If you hear a clicking sound, it could mean one of several things. Loose debris in your compressor is the easiest to deal with. If you suspect something is interfering with your condenser's fan, turn it off and see if you can remove it yourself. If not, hire an HVAC technician to tune-up and clean the unit. The more difficult problem could be electric. If the electric is old or frayed, it can make a clicking noise.

Humming or Buzzing

Humming or buzzing noises are among the most irritating AC sounds, but they should never be ignored. Buzzing can indicate a variety of issues, ranging from a failing compressor to damaged condenser feet. If you hear a buzzing, it could mean that your air conditioner has frozen over, or that there are some loose parts rattling around. While you can keep your air conditioner running with some buzzing, you should contact an HVAC technician to diagnose and repair the problem.

Squealing

Squealing is an unpleasant sound. It can even cause ear pain. We all know that cars can squeal, but what about your air conditioner? Yes, your air conditioner can make a loud squealing noise, and if you hear it, don't ignore it or push it aside. Squeals are frequently indicative of a loose belt that needs to be replaced or readjusted. Furthermore, belts can expand and contract in response to outside temperature, potentially exacerbating the already obnoxious AC noise.