Why Is My AC Making Weird Noises?

Nothing says “summertime” like the calm, steady hum of an air conditioning unit. And nothing ruins the peace like bizarre air conditioner noises sounding like there’s an angry cat trapped inside of it.

Modern A/C units are designed to avoid making noise, so if you hear hissing, rattling, banging, or other loud noises—it might be time to get yours professionally inspected and serviced.

To help diagnose the problem with your noisy air conditioning unit, we’ve assembled this guide to common issues resulting from wear and tear or malfunction.

Common Air Conditioner Noises and the Problems Causing Them

Banging sounds coming from your air conditioner noises may be a result of a condenser issue, but can be any of the following problems as well:

• Dirt, leaves, or sticks caught in the condenser

• Loose screws

• Broken compressor or fan motor

If your unit is near shrubbery, then foliage may have entered the unit causing the unwanted sounds. However, in some instances (such as when the noise begins right when the AC is turned on), the banging results from a broken compressor. In this case, contact an HVAC professional to have your unit serviced.

Rattling Noise

Like a banging noise, rattling noises may be caused by loose screws and sticks. In the worst-case scenario, it may be a broken electrical contractor in your air conditioner. Have it fixed as soon as possible to prevent further damage to the system.

Pulsating Noise

A pulsating noise may be nothing to worry about—some air conditioners make that sound while operating normally. However, if the pulsating has changed or you believe it sounds out of the ordinary, it may be due to a malfunction. Common causes are loose fan blades, loose plastic bases, or refrigerant lines contacting the wall of the air conditioner.

Hissing Noise

If your air conditioner sounds like a snake is trapped inside, it may be due to a moderate or severe air duct leak. It could also be a leaky refrigerant line, a compressor valve leak, or excess compressor pressure. In any case, don’t try to fix it yourself—contact an HVAC maintenance professional.

Clicking Noise

Clicking when turning on the air conditioner is normal, but electrical problems may cause clicking that doesn’t go away. Your capacitor may lose its charge, or the AC unit’s electrical signals may be faulty. If you see sparks accompanying the clicking, turn the unit off immediately.

Buzzing Noise or Humming Noise

Buzzing sounds can indicate a serious problem with the air conditioner. Some culprits include:

• Dirty condenser coils

• Loose fan blades

• Obstruction near copper lines

• Electrical issues

Squealing or screeching is the most common irregular air conditioner noise (perhaps the most irritating!). It is typically due to an issue with the fan motor and its motor bearings, although a broken motor in the compressor or condenser might also be the problem.

Whistling Noise

If your air conditioner is whistling, congratulations, you’re in luck! Whistling is usually one of the least serious types of air conditioning noises. Your AC duct may leak, or there could be a blockage in the air conditioner airflow. While these problems are not critical, you should still turn to a professional to fix them.

Other Air Conditioner Noises

Sounds not mentioned that you may be hearing from your air conditioner include clicking sounds, grinding noises, popping noises, dripping, or bubbling. These can be hard to diagnose without professional inspection—so a general rule of thumb is to have any AC noises checked out sooner rather than later to avoid further damage.

What to Do About Air Conditioner Noises

Although some air conditioner problems might seem like an easy fix, it’s best to get a professional on the job. Air conditioning units are complex, and quality air conditioner repair can save you money in the long run.

Don’t Wait for a Problem – Schedule an Inspection Today!

Stack Heating, Cooling, Plumbing & Electric has been helping Cleveland homeowners for over 45 years. Our technicians are experienced in HVAC inspections, repairs, and maintenance, so you can trust us to keep your system running smoothly. Call us today at (440) 937-9314!