Why is My AC Making Noise?

Help! My AC is Making Noise

 Don’t panic, an AC making noise might not be as disastrous, or costly, as you might think. The first step will be to identify whether you’re hearing the noise from inside your home or outside while next to your unit. There are common component malfunctions that have an easy and quick solution, either from an ambitious DIYer or from a licensed professional. Here are some of the noises your air conditioning can make, and how to interpret these sounds.

  1. AC Makes a Banging Noise

There can be several culprits behind the banging noise you hear when your AC shuts off. One of the most common can actually be caused by your air filter. When your air filter clogs, or if it’s too restrictive, it causes your unit to work overtime. This means your air conditioning unit is working hard to pull in air, and it might be pulling your air filter tight against its frame, so when the unit shuts off, it releases the air filter, which slams against the grille. This problem has an easy solution, simply replace your air filter with a lower MERV rating if it’s too restrictive, or with a clean new filter if it’s dirty.

Other reasons you may hear a slamming sound include:

  • Expanding and contracting ductwork
  • Closing dampers to regulate the amount of airflow moving through different areas of your home
  • The fan in your outdoor unit might have loose components
  • The AC compressor’s support springs have become unbalanced or need replacement
  1. AC Is Making a Buzzing Noise

If you hear a buzzing noise coming from your AC, it’s often related to a malfunctioning compressor. The compressor works to pressurize and cool the refrigerant that cools your air. If this is buzzing, you’ll need a professional to inspect the unit. Before calling someone out, you may want to check if the compressor’s rubber feet are disintegrated, this can also cause a buzzing sound. On the other hand, an electrical buzzing noise could mean that your unit is not getting the right amperage.

  1. AC Is Making a Hissing Noise

If you have noticed a drop in temperature in your home and it feels like the air pushing through your vents has dropped in pressure, it might be due to broken or leaking air ducts. Consider calling a professional to check your ductwork.

  1. AC Is Rattling or Humming

If your AC unit is rattling, it could be a sign that parts are coming loose. Something as simple as a loose bolt, loose wiring, or a twig stuck in the unit could cause humming and rattling. If you’re familiar with your HVAC unit, turn it off and make sure that it doesn’t have any debris caught inside and that all the components seem tidy and tightly installed.

  1. AC Sounds Like Screaming

If your AC is making a loud screaming noise, it’s important to shut it off immediately and call an HVAC professional. This noise typically signals that you have a hazardous refrigerant leak which can break your unit.

Now that you’re familiar with the potential causes of a noisy AC unit, you’ll be better equipped to troubleshoot the problem or give your HVAC repair professional a knowledgeable guess of the issue you’ve witnessed. Regular AC maintenance and properly fitted air filters can go a long way in stopping problems before they happen.

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