Is It Possible for an AC Compressor To Make a Knocking Noise?

Depending on the type of air conditioner, modern HVAC units use sound-dampening technology to keep the sound level between 25 and 55 decibels. The sound of a whisper is 25 decibels, while a normal mid-level conversation is 55 decibels. According to experts of AC installation in Nogales, AZ any air conditioner that makes loud and unusual noises is most likely malfunctioning or needs special attention.

Common Causes of a Loud Knocking or Banging Sound:

A Faulty Component in the AC Compressor

This is the part of the outdoor unit that is housed. It could be the piston pin, connecting rod, or crankshaft. The fan’s blades may collide with other parts of the compressor, resulting in a loud knocking noise. In many cases, a compressor replacement is required; in others, the loose part must be tightened or replaced. If you keep using it, it will need AC replacement in Nogales, AZ, sooner than expected.

An Unbalanced Blower

The “fan” unit is the blower, usually found indoors. As the fan spins, it will make a banging or knocking noise if unbalanced. If your air conditioner produces a loud noise from inside the unit, the bangs could be caused by a broken fan motor or an imbalanced motor. It will be costly to replace the motor, so speak with a professional performing AC replacement in Nogales, AZ l to understand the situation better.

The Compressor has Something Stuck Inside it.

Because your AC compressor unit is outside, small objects such as twigs and acorns may fall inside. If this occurs and an object gets in the way of the fan, the fan will strike the thing. This could result in a knocking or banging noise depending on the object’s material.

Other Unbalanced or Loose Components

If the sound is more like clanking, it could indicate that the compressor is loose or that parts inside the blower unit collide. A professional must address these issues as soon as possible, or they will worsen.

Ways to Reduce the Noise from the Air Conditioner

  • You have options for removing AC noise if a service professional finds nothing wrong with your air conditioner or if you’re looking for ways to muffle the sound of a newly installed unit.
  • A sound blanket is one such option. You can take the top off your AC outdoor unit and place a sound blanket on the compressor.
  • Place some large houseplants in front of the windows on the side of the house facing the AC to block out noise. You can also put some shrubs around the AC, but you’ll have to keep them pruned back carefully.

Reasons to Pay Attention to AC Noises

  • When your air conditioner behaves strangely, it’s trying to alert you to a problem. Ignoring unusual sounds from your HVAC system can turn a minor problem into something potentially harmful to your health in the long run.
  • If a refrigerant leak is the noise source, it can be dangerous. The sooner you can identify and resolve the noise source, the better your unit’s overall performance.
  • It’s best to figure out what’s causing strange sounds from your air conditioner as soon as possible to avoid costly repairs down the road.


If you are looking for a budget-friendly and trustworthy AC installation in Nogales, AZ, Santa Cruz Heating & Cooling can help. Call us at 520-313-1424 or drop us a mail here to know more about our services.