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A well-run air conditioning system operates with minimal noise that eventually fades into the background. After you turn on the system, you initially hear the startup of the motor and the buzz of the air compressor; however, it gradually disappears from your mind, and the sound doesn’t affect you. When there are unusual AC noises, the system is communicating that there is something seriously awry.

When you hear sounds that aren’t normal coming from your air conditioner, it doesn’t necessarily result in the system shutting down or failing to operate. However, ignoring the noise could mean more significant damage in the future. HVAC contractors advise always to address elements that seem off. You could experience various sounds with each of them, resulting in a different issue. These are some of the noises that signal there could be something wrong with your air conditioning.


Buzzing Sound

When your system gives off a loud, buzzing sound, there could be several issues. There may be loose or broken parts, a damaged compressor, refrigerant leak or a missing part from the isolation feet. An air conditioning system comprises multiple components, big and small, all working together efficiently. A primary cause of the buzzing sound is often one of the isolation feet that may have broken after years of service, causing the compressor to become imbalanced to produce the offending sound. You simply replace the isolation feet or adjust the compressor to a stable position which should eliminate the noise.

The compressor can also be the source of the noise when the electric voltage is either too low or too high. Since it is a central part of the system, it’s critical that you enlist the services of a professional to fix your AC.

A refrigerant leak could be responsible for the buzzing sound. However, that points to a deeper problem, and you should address it immediately. If you leave this problem unattended, you will find yourself with a completely broken air conditioner.


Drip Drop

If you hear the sound of water drops, there’s no immediate cause for concern. Air conditioners create condensation, especially when they’re operating at maximum capacity. As a result, the water droplets that the system captures from the air have to escape and wind up on a drip pan. It’s perfectly normal to hear this sound, but if it’s too much to handle, you’d have to open the system and empty the drip pan.

However, if you hear the sound of water running or splashing, there could be an issue. The condensation may be excessive and not draining efficiently. Furthermore, your drip pan could be overflowing with water. Apart from this, these are the other reasons you may hear the sound of water running and dripping inside your air conditioning unit.


  • There is a blockage in the drain line
  • There is a crack in the drain pan
  • The contractor didn’t install the unit itself correctly or the size is wrong
  • The condensate pump isn’t functioning
  • The air filters may be dirty
  • The system may be out of refrigerant


If you experience any of these issues, you can expect your unit to bow out soon. Depending on how severe the faults are, you may require an AC repair in Santa Rosa.



Rattling is a typical sound, especially on the outdoors part of the unit. A side panel may have loosened, causing it to vibrate back and forth when the compressor is in operation. Additionally, any twigs, leaves, branches or outside elements could get stuck around the system resulting in the rattle when it’s running. If you find the rattle from the inside, then there is a mechanical problem such as the fan blower motor which requires the skill of a professional contractor.



If there’s nobody around yet you hear a whistle; your system is communicating that there is a blockage where the air is supposed to enter. The most common problem for this sound is a blocked or dirty filter. You will experience this sound if something is blocking the vents as a result of the closure of the register vents.



A common occurrence is a door or side panel that is loose, resulting in a clicking sound. Elsewhere, something may be hindering the fan blade from its function or it’s been bent and out of balance. If you find that you can’t isolate the sound and identify the problem, rather call in a qualified contractor before the issue becomes greater.



Similar to a tire that’s losing air, you may hear your system hissing. This sound is evidence that there is a leak somewhere in the air conditioner. It’s highly likely that there is a refrigerant gas leak. The air conditioner reduces its performance until a contractor resolves the issue.



While there are some sounds that you can troubleshoot on your own, you should call in a professional for any assistance. At Valley Comfort Heating and Air, we have skilled technicians who possess the knowledge to get your air conditioning operating efficiently again.