Knowing Why Your Residential Air Conditioning System Is Making A Buzzing Sound


If you rely on a modern air conditioner to cool your home during the hot summer months, you're probably familiar with its quiet operation. If the unit starts making unusual noises while it's running, this is an indication that something's wrong and immediate investigation must be initiated. 

One of the most common AC noises that you should keep an ear out for is a buzzing sound coming from your AC system. While this type of AC noise can be caused by many factors, take a look at some of the usual culprits below.

Frozen Evaporator Coils

If you hear a buzzing sound coming from your AC system's indoor unit, this is a signal that the evaporator coils are freezing over. This can happen due to a number of factors, including:

  • Dirty evaporator coils
  • Low refrigerant level
  • The AC thermostat being set too low
  • Ineffective air filters

To stop the noise and prevent your evaporator coils from freezing, you'll need to identify and address the specific factor or combination of factors that are causing the problem.

Faulty Condenser Fan Motor

If the buzzing noise is originating from your AC system's outdoor unit, the problem could be a malfunctioned fan motor. The fan motor is the electrical component that drives the outside fan, which blows cool air over the condenser coils.

If it's not working, the outside fan won't turn and may instead generate a loud buzzing sound. Some potential causes of fan motor failure include but aren't limited to the following:

  • Obstructed fan blades
  • Bad capacitor 
  • Unbalanced fan blades
  • Issues with the AC's circuit board

If your outdoor fan motor isn't working, the fan blades won't turn and this means your compressor could easily overheat and fail. You'll need to fix the problem to avoid a catastrophic equipment failure that may lead to costly repairs or premature replacement of the equipment.

Loose Components

Like other mechanical equipment, air conditioners contain many parts that may come off loose during normal operation. These include:

  • The screws that keep your equipment secured in place 
  • The wiring that provides power and directly connects to your equipment 
  • Loose internal components such as fan bearings and belts

The good news is that loose AC components typically require relatively easy fixes. All you need to do after you've identified the problematic component is to make sure it's reattached securely.

One of the surest ways to encounter AC failure is to ignore any signs of trouble with your home's cooling system. If you hear a buzzing noise or other strange noises coming from the system, don't hesitate to contact a local HVAC technician for diagnosis and air conditioning repair


18 August 2021

Cool off Your AC Bill

Every summer, I agonized over energy bills that would shoot into the stratosphere as a result of my efforts to keep cool in the heat. Every time I turned the temperature down, my bills increased. This summer, I decided to take some of the control over my energy bill back. I installed reflective film on my windows that reduced the amount of light and heat coming into the house. I started serving more cold meals or asking my husband to barbecue outside, so that my air conditioner didn't have to compete with the hot stove, and I started doing laundry at night to reduce appliance heat in the house at peak times. I also had ceiling fans installed. So far, the difference in my bill has been tremendous. This blog is a way for me to explore other ways to reduce energy drain during the summer months.