Strange Noises Your AC Unit Makes and When You Should Be Concerned

During the summer, you probably rely on your air conditioner to keep your home cool and comfortable. Most of the time, it hums along in the background, providing you with cool air without giving you much trouble. If it starts making unusual noises, however, it can be very off-putting. How do you know if a noise is normal, or if it’s something that requires professional attention?

Air conditioners often make some strange sounds. The important thing is to make note of the type of sounds you’re hearing because different noises mean different issues. Do any of the following descriptors seem familiar?

  • Squealing: Typically, if your HVAC unit is making a high-pitched squealing noise, it’s either the belt connecting the motor to the blower or the bearings on the motor of your condenser fan. Newer units don’t usually have a belt, but if your unit is older and you’re hearing the sound both inside and outside your home, the belt is probably the problem. It may need to be replaced, or it may just need lubricant. Even if it’s as simple as a lubricant, it’s not a bad idea to go ahead and replace it, because when the belt breaks, the air conditioner stops blowing. With a newer unit, squealing is probably caused by the condenser fan motor’s bearings. Direct-drive motors don’t use a belt, but bad bearings can cause squealing and grinding from the outdoor unit. When this happens, the motor probably needs to be replaced. Note: if your air conditioner always makes a squealing sound when it first starts up, but the sound stops after a little while, it’s probably not actually a problem.
  • Buzzing: Loud buzzing noises coming from the air conditioner are usually bad news. The issue may be loose parts, missing or broken isolation feet, leaking refrigerant, or a compressor that’s malfunctioning, but whatever it is, it indicates a need for repair. If one part goes bad, it can put stress on the rest of the system, so it’s important to have repairs made as soon as you know something is wrong. Buzzing may mean that the rubber feet at the base of your air conditioner have begun to disintegrate or crack, causing the compressor to become out of balance, which creates the buzzing sound. It may also mean that the refrigerant has begun to leak, which can cause your AC to actually freeze up and stop working. On the other hand, the buzzing may be the result of an electrical problem or a malfunctioning compressor. It could also be due to debris in the unit, either indoors or outdoors, loose parts, copper lines rubbing against something, an air filter in need of changing, or a condenser coil that needs cleaning.
  • Chattering: Whether or not this is serious can’t really be determined just by listening. It could mean that your HVAC is on the way out, and the parts are starting to loosen. On the other hand, it could just mean that twigs or leaves have clogged your system. The first thing to do if you hear a rattling, chattering sound is to check for loose screws in the casing of your unit, then clean the condenser coils and change the air filter.
  • Whacking: This sound is often more annoying than it is serious. It probably means that there’s debris lodged in your motor blades, and it’s time to clean it out before it leads to bigger issues.
  • Clicking: It’s normal to hear clicking at start-up or shutdown of your system, but if the clicking keeps going, it could be a sign of a defective control or a thermostat that’s about to go bad. As with any electrical issue, it’s important to deal with It as soon as possible.
  • Humming: When your air conditioner is humming, you should probably have your unit checked out by a professional. It may not be a serious problem, but it could indicate loose parts that can lead to a more serious issue, or it could indicate electrical problems.
    Clanking or Rattling: This probably means that a part inside your air conditioner is loose, out of balance, or misaligned. Do not ignore this kind of sound, because there’s a significant chance that these out-of-whack parts can lead to bigger problems.
  • Thumping or Banging: When the noise in your air conditioning unit moves beyond rattling and clanking and on to thumping or banging, it means that something serious is amiss. Most likely, a broken part has come loose and is being thrown around your unit. If that’s the case, it must be repaired quickly, before the loose part causes damage to the rest of your system. Thumping and banging can also mean your compressor needs to be replaced.
  • Screaming: If your air conditioner starts screaming, turn it off immediately and call in a professional. A screaming sound can mean a refrigerant leak, which may be harmful to your family’s health, or high pressure inside your compressor, which is an extremely dangerous situation. In fact, your compressor may turn off on its own as a safety measure.

It’s important to know who to call for repair, and it’s also smart to have annual maintenance, to prevent these repairs from becoming necessary in the first place. If you need to find a professional to check your HVAC, or you’re in the market for air duct cleaning, repair, and replacement services in Tampa, St. Petersburg and the surrounding area, please feel free to call Air Rescue at (813) 375-9982. Since 1946, our family-owned business has been providing superior service at unbeatable prices, offering heat and air conditioning repair services, new HVAC system installations, and more for homes and businesses. The service team at Air Rescue Air Conditioning consists of 75 expertly trained and licensed technicians, who work quickly and efficiently. Our service and pricing guarantee ensures that we always arrive on time, offer you the lowest price in the industry, and leave you 100% satisfied. Schedule your service visit today, and we’re confident that you’ll make us our HVAC company for life.

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