AC Noises: What They Might Mean and How to Fix Them

Woman covering her ears with pillow from loud HVAC air conditioning system noises

Summer is in full swing, which means one thing for many people: using the air conditioner (AC) to keep cool. However, it's time to investigate what's happening if you've heard strange noises from your AC unit.

According to the Environmental Protection Noise Policy 2007, you may be penalized for creating "unreasonable noise" from household appliances.

The air conditioner decibel levels specified are 50 dBA for window units and 60 dBA for central air conditioners. If your AC is older, it may be louder.

It includes air conditioners, so it's essential to figure out what's causing the noise and take steps to fix it.

1. Humming Noise

The AC compressor is responsible for circulating the refrigerant through your AC unit. If you hear a humming noise, it’s likely coming from the compressor. It is usually nothing to worry about and can be fixed by simply tightening any loose bolts.

If you hear a louder humming noise, it could signify that the compressor is failing and will need to be replaced.

Common reasons for a compressor failure include:

  • Lack of maintenance
  • Improper installation
  • Faulty electrical connection

2. Rattling Noise

AC components like the fan blades and blower wheel can become loose over time and start to rattle. You might be able to hear this noise coming from inside or outside your home.

If the rattling noise is coming from inside your home, check to see if any of the AC components are loose.

Contact the manufacturer for repair or replacement if your AC is under warranty. They may offer to replace the fan blades or blower wheel for free.

Read more: How Long Are AC Units Under Warranty?

3. Buzzing Noise

The AC transformer is the most likely cause of a buzzing noise. The transformer increases or decreases your home's electricity voltage to make it compatible with your AC unit. If the transformer is going bad, it can cause a buzzing noise.

Another issue could be a faulty capacitor. The capacitor is what helps the compressor in your AC unit start-up. If the capacitor goes bad, it can also cause a buzzing noise.

Expert HVAC technicians can quickly diagnose whether your transformer or capacitor is the issue and replace it if necessary.

4. Clanking Noise

The valves and motor mounts inside your AC unit can loosen over time and cause a clanking noise when the unit turns on. One way to fix this is to tighten any loose screws or bolts. If the noise persists, it could be a sign of a more serious issue like a cracked heat exchanger, which will need to be replaced by a professional.

Moncrief offers expert AC repair in Atlanta. Our HVAC team can help you with strange noises from your air conditioner and any other maintenance or repair needs. Our services are guaranteed, and our team is highly skilled, so you can be confident that your AC is in good hands.