Air Conditioner Noises That Signal the Need for Professional Repair

You probably don’t think much about your air conditioning system as long as it is providing consistent cooling. It will normally make a quiet hum as it runs, but do you hear it making a different kind of noise? This could indicate a problem with your unit that should be addressed by a professional technician as soon as possible.

Schmitt Heating & Air Conditioning explains some of the unusual HVAC noises and what they mean.


If you hear a squealing noise while your unit is running, it might be because of high internal pressure from its compressor. Normally, this component increases pressure as it compresses the refrigerant into hot gas, and if the pressure gets too high, the built-in sensors turn off the system automatically. But this may not always be the case, which leads to an unusual squealing sound while it’s turned on. It can also be due to a loose fan belt. Either way, the unit should be turned off and checked by a trusted technician to prevent further damage.


A banging noise that’s coming from your heating and cooling unit is often a clear sign of a loose or broken component inside the compressor, which usually requires a replacement. It may also be due to an unbalanced indoor blower. Make sure to get in touch with your technician as soon as possible to determine the cause of the banging noise.


This type of noise is normal if you hear it while starting up or shutting down the unit. But if you notice the noise getting more constant and faster while it’s running, it may be time to get it checked by a professional. If the clicking noise is coming from the outdoor unit, see if it gets faster as it’s running. There could be an obstruction in the unit’s fan. If it won’t start at all and you hear steady clicking noises, it’s more likely an electrical issue.

If you need an HVAC service technician to take a closer look at your unit, don’t hesitate to call Schmitt Heating & Air Conditioning! You can reach us at (415) 522-0966 or fill out our contact form to schedule a consultation. We serve homeowners in San Francisco and the neighboring areas.

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