Funny AC Noises – What Should You Do When Your Air Conditioner Doesn’t Sound Right?

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Does your air conditioner wake you up in the middle of the night with loud clanking noises? Do you hear strange clicking sounds when you adjust the temperature on your thermostat? Here in Phoenix, as we move into the hottest part of summer, your air conditioner is starting to work overtime and may be trying to communicate with you in a secret language understood only by AC service technicians and air conditioner whisperers. Ka-chunking means one thing, while whirring and whining means something else. Clicking, hissing, screeching, humming and other sounds can be indicators of specific problems with your air conditioning unit. Here’s a list of some of the more common AC noises and what they generally mean:

  • Loud Ka-Chunk or Banging Upon Startup

    Loud banging noises at startup from your outside compressor are often noticed at night when everything else is quiet. This might indicate there’s a loose part or a significant problem with your compressor. Many times, homeowners hear the noise, shrug their shoulders and go back to sleep. However, if the noise continues to get worse, it means your compressor may need service. It’s better to have your compressor checked before it fails completely.

  • Ear Splitting Screeching

    This is one of the most cringe-worthy sounds your AC unit can produce. Loud, metal on metal screeching will most likely be your fan motor bearings crying out to be replaced immediately.

  • Clicking Noises

    It’s normal to hear a single click after you adjust the thermostat and just before your AC unit kicks in. However, if you hear recurring clicking noises and your unit does not startup, it could be trouble. Repeated clicks generally indicate an electrical issue, such as a burned-out capacitor or a possible compressor problem. As with all electrical issues, it’s best to call us for service right away.

  • Rhythmic Clicking

    A constant tick, tick, tick clicking usually turns out to be a branch, or some other kind of obstruction hitting the edge of the fan blade as it rotates. These wind-blown branches are easy to remove.

  • Gurgling

    The sound of gurgling water lets you know your condensate drain line might possibly be backing up or require some attention. Your air conditioner’s evaporator coil produces condensation, so water is constantly draining. However, clogged drain lines are a common occurrence and easily remedied.

  • Humming or Buzzing

    When electric motors fail, they often hum or make a buzzing sound. If you notice your unit is not starting up, you hear a loud hum and you see smoke or notice an electric burning smell, turn off your unit immediately and call for service. Please remember, AC units are loaded with wiring and electrical components which can cause fires.

  • Faint Hissing

    Hard to hear if there are any other sounds around. However, a faint hissing is heard when refrigerant is escaping though a pinhole in your pressurized lines. It can also indicate a leaky compressor valve. Losing refrigerant adversely affects the overall performance of your air conditioner and should be serviced immediately. Refrigerant is a colorless, toxic gas and when leaking, requires immediate attention.

  • Whining

    No one likes a whiner. Similar to an automobile, when your air conditioner starts in with a high-pitched whining it usually means the fan belts need to be replaced.

Is Your Air Conditioner a Symphony of Cacophony?

The only noise you really want to hear from your air conditioner is the quiet whoosh of the fan blowing cool relief into your home. Other than that, the unpleasant cacophonies described above are your air conditioner’s desperate cries for help. Has it been awhile since your last AC checkup? With August and September just ahead, now is a great time to schedule an HVAC inspection to make sure you’re all set for the hottest months of summer.