Is Your Air Conditioner Making a Humming Noise? - Day & Night Air Conditioning, Furnace, & Plumbing

It’s just a little hum; how bad could it be? We regularly hear from homeowners in the Phoenix, AZ area, who ignored signs of common air conditioner problems because they didn’t want to spend the time and effort required to get A/C repair. Unfortunately, the personal anecdotes we hear from people who ignored the air conditioner making noises normally turn into horror stories. There is a reason that hiring a professional technician is important to the overall safety and longevity of your A/C unit.

A humming sound isn’t always especially serious compared to other noises your air conditioner might make, but that isn’t a reason to ignore it. In fact, it’s a reason to address the problem right away before it does get serious. Air conditioner problems don’t just go away on their own, and they normally get worse over time. The best way to save yourself time and money when you hear your air conditioner humming is to take immediate action.

Air Conditioner Humming Inside

You may be able to hear this sound coming from your vents. This normally means the noise is actually originating at your inside unit, but it’s able to travel through the ductwork and reach you. If you hear a noise that seems to be coming out of your vents, go to your inside A/C unit and see if you can confirm that it’s the true source of the noise. Once you can determine where the noise is coming from, it’s a lot easier to determine what’s causing it.

Causes of Inside A/C Humming

Humming from the inside air conditioner unit isn’t nearly as common as it is from the outside unit, which makes this problem slightly easier to diagnose. If the noise is coming from the part of your system inside the house, there’s a good chance it’s caused by one of three things:

1 - Frozen A/C Unit

If you’re getting ice buildup inside of your air conditioner, it means you have other problems leading to the freezing. This could be low refrigerant, a faulty fan, or poor airflow inside the unit. Low refrigerant levels make the coils get too cold (even though this seems counterintuitive to some people), and broken fans or blocked airflow prevents warm air from going over the coils to keep them from freezing. The other reasons for this problem might include poor drainage or bad signals from the thermostat.

2 - Loose Components

There could be a broken or failing part inside of your air conditioner. The unusual movement could generate a humming noise as the part spins wildly, rubs against something else, or otherwise moves awkwardly.

3 - Electrical Problems

Sometimes, electrical problems might sound like humming. When circuit breakers, relay switches, and other electrical components fail, the electricity can make a humming or buzzing noise. Many of these components are actually outside of your indoor A/C (such as in the breaker box or the outside unit), but it’s always a good idea to be aware of electrical buzzing and call an expert for help.

What to Do About Inside A/C Humming

The best thing you can do for any of the causes above would be to turn the system off and call for help ASAP. The problems mentioned above are extremely difficult to fix by yourself unless you have significant training as an HVAC contractor or possibly as an electrician. Attempting to repair them by yourself can be dangerous for you as well as for your system itself. Turning off the system prevents the problem from worsening and allows the system to thaw if it’s frozen, which is important to do before freezing can spread through the pipes.

Understandably, on a hot summer day here in Maricopa County, the idea of turning off your air conditioner isn’t ideal. Still, it’s the best thing you can do for the health of your system. Call an HVAC company that responds quickly, and they’ll come to the rescue as soon as they can. If needed, you may want to go somewhere cooler if you have to wait for a couple of hours.

Air Conditioner Humming Outside

Most of the time, people call with a complaint that the air conditioner is humming; they’re talking about a humming from outside the house. You might hear it while you’re going in or out of the home or while you’re relaxing in the yard. In either case, this issue can normally be traced to a few different things.

Causes of Outside A/C Humming

Humming from the inside unit could have to do with an electrical problem or loose components. Buzzing from a loose part sounds a lot different than electrical buzzing.

Perhaps the most common cause, though, is the capacitor. This is essentially like a massive battery that stores a lot of energy. It helps start the compressor, the indoor unit blower fan, and the outdoor fan motor. Like batteries, these things can eventually go bad. The high temperatures we experience here in Arizona often reduce the amount of time a compressor can last.

If your compressor is bad, you may be able to notice the following signs:

  • Your outdoor A/C unit is humming, but the fan is not running.
  • The capacitor is swollen on top like a battery that has started to explode.
  • There is fluid leaking out of the capacitor (like liquid is a bad sign for your car battery).
  • The capacitor looks rusted, corroded, or otherwise physically damaged in any way.

What to Do About Outside A/C Humming

If the capacitor is completely broken, your air conditioner won’t be able to turn on properly. The heat exchange will be disrupted, which means your system will no longer be able to cool your home. You may notice warm air coming from A/C vents at this point. This is an obvious sign that it’s time to call in the professionals as soon as possible before your home becomes unbearably hot.

Even if your air conditioner is still blowing out some cool air, it probably won’t be for long. The sooner you can replace your capacitor, the better off you will be. Quick repairs prevent your house from getting uncomfortable and can also prevent other damage.

Even if the capacitor has failed, the motor will still try to come on. Normally, though, the motor won’t be able to start up without the capacitor, so it just keeps stalling as it unsuccessfully tries to engage. This activity is hard on the motor and can cause it to burn out prematurely, ultimately making the repair much more expensive.

Air Conditioner Repair in Phoenix

Whether you notice your air conditioner humming inside or outside, your best bet is to turn the system off and call Day & Night Air Conditioning, Heating, and Plumbing. As a full-service HVAC company in Phoenix, we know about the challenges of keeping a home comfortable in this part of the world. We’ve also seen just about everything, so our qualified HVAC contractors will be able to diagnose and repair A/C humming as soon as humanly possible. Schedule online at your convenience.

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