Why Is My AC Making a Loud Buzzing Noise

April 14, 2016

You might hear many noises coming from your central air conditioning unit. One noise can be very distracting, even irritating. If your AC unit is making a humming noise that just seems to get louder and louder, it is a good sign that something isn’t right within the unit.

Buzzing or humming noises are usually caused by an electrical issue and will happen as your system gets older. If you hear the buzzing sound it is a good idea to call an HVAC expert straight away to schedule an air conditioner repair.

5 Reasons Your Air Conditioner Is Making a Buzzing Sound

Here are five reasons your air conditioner may be making that very distracting buzzing sound;

  1. The Contactor Relay Switch.  This is a low-voltage switch that is located in your outside unit. This switch is controlled by the inside thermostat. The good news is if the switch is the problem it could be a simple and not so costly fix.
  2. Circuit Breakers. If your circuit breakers are failing or malfunctioning they can cause the humming sound to come from your outside unit.
  3. Condenser Fan Motor. This is the huge fan located in your outside unit. Your inside blower may be working but the condenser fan may stop turning, this results in a buzzing or humming noise.
  4. Electrical Connections. If electrical connections are aging or they come loose this can cause electrical arcing which will then result in a humming noise. If you don’t get the electrical connections fixed the humming sound may turn into your AC shorting your power on a regular basis.
  5. Frozen Unit. If your AC unit is frozen or it continuously freezes up this can cause a humming or buzzing sound. Switch off the unit for a few hours and let it defrost. If the unit still doesn’t work call an expert.

What to Do if You Hear a Buzzing Sound

If you hear a buzzing sound you should turn off your air conditioner immediately. Continuing to run the system, even if the air feels cold, could cause more damage to your AC unit. It may also become a safety hazard, putting your home and those living inside at risk.

Once you have turned off your unit, call a professional. If your unit is frozen you can let it stand for a couple of hours first. If it continues to not work or if it continues to freeze up on a regular basis, you will need to call for repairs.

If your air conditioner is making a buzzing noise or you are in need of AC repair, contact the team at Rick’s Heating & Cooling today. For over three decades, we have been repairing air conditioners throughout the Morrow and Cincinnati metro areas in Ohio.