5 Common Air Conditioner Noises & What They Mean

Air conditioning should be felt and not heard. Beyond some startup sounds and a low hum, you don’t want to hear much buzzing or clanking coming from an air conditioner.

Take these air conditioning noises as a sign that you need to take action before the equipment suffers more serious problems. A quick air conditioning tune-up now might save you from a sudden failure in the middle of summer.

1. Loud Humming or Buzzing

Extra vibrations from loose components can build up to a deafening racket of humming or buzzing. The vibrations may be coming from the electrical wiring or refrigerant line, or simply from some loose screws.

2. Hissing or Screaming

If you hear a screaming sound from the air conditioner — not just squealing, but a loud and high-pitched hiss — be safe and shut it down. Screaming sounds typically indicate a serious problem with the compressor or refrigerant. If you let it run, the air conditioner might suffer a significant and potentially dangerous breakdown.

3. Banging

Some equipment might make some banging sounds at startup, but if the air conditioner makes banging sounds while it’s running continuously you probably have some parts that need to be tightened or replaced. The compressor, blower, fan, or equipment housing is off-kilter and might be damaged.

4. Clicking or Rattling

Again, some startup noises like clicking or rattling can be normal and not indicative of a problem. Don’t ignore loud clicking, however, especially if the air conditioner only recently started to make the sound. You can try cleaning out the outdoor AC unit if possible. There might just be leaves or debris creating the rattling sound. If you can’t spot the problem, call an HVAC pro to inspect.

5. Dripping, Gurgling, Wet Noises

If you hear liquid sounds coming from an air conditioner, it’s related to either the refrigerant or condensate line. Refrigerant problems are very serious, but so are condensation issues. Condensate drain lines and drain pans getting knocked out of place and dripping or backing up, and that can lead to corrosion, freezing up, and other damage.

When to Call HVAC Repair for a Noisy Air Conditioner

Some air conditioner noises are symptoms of significant problems. You should turn off your air conditioner immediately if it’s also struggling to cool your home properly or if the noise seems especially loud or strange.

Some DIY air conditioning solutions for noise include removing debris from the outdoor unit, tightening screws on rattling parts, and making sure the filter and vents are clean and unobstructed.

Finding the source and cause of air conditioner noises can be very tough, and the solutions often require a licensed HVAC technician.

Can’t stand the noise anymore? Worried about your air conditioner’s performance? Contact Metro Heating & Cooling or call 314-845-5900 for air conditioner repair in Fenton, MO or anywhere in the St. Louis area.