Air Conditioner Making Noise? Here’s What You Can Do About It

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You’re feeling a little hot, so you head over to the thermostat to turn on the air conditioner. What do you hear? Some air conditioner units emit a noise when they are first turned on; after all, an air conditioner is a large machine with many moving components! However, most units (especially newer models) continue to run relatively quietly. Of course, some brands are noisier than others, but what if you constantly hear loud noises from your unit? Or what if you suddenly hear new noises from your unit? Not only can a loud air conditioner be annoying, but it might also cause you to worry. Some noises can be easily fixed while other noises may indicate a problem fit for a professional.

Loose Fan Blades

Is your fan rattling? This sound may indicate that there is debris around your fan or the fan blades themselves are loose. More often than not, a rattling fan is a problem that you can easily fix on your own.

  • Remove any debris from the inside of the air handler cabinet. You can use your vacuum if necessary. For hard-to-reach areas, use the vacuuming wand.
  • Clean the fan blades: wipe down any dust that has accumulated on your blades
  • Tighten the fan blades: Most fan blades can be tightened with a screwdriver or an Allen wrench. You’ll want to avoid using a power drill, so you don’t accidentally strip the screws.

Bent Fan Blades

Bent fan blades can also cause a rattling noise. This too can be easily fixed without calling in a professional. Here’s what to do:

  • Visually inspect the blades for any signs of damage.
  • If you see a bent fan blade, you can carefully and slowly apply gentle pressure as you straighten the blade.

If you have a severely bent fan blade or a broken fan blade, you might want to consider calling for the help of an HVAC technician.

Lack of Lubrication

Humming noises are a common complaint when it comes to noisy air conditioner units, and a lack of lubrication is usually the cause of these humming (or even grinding) noises. Here’s what to do:

  • Listen: Is the sound coming from the blower motor? If so, the motor probably needs a little extra lubrication.
  • Look: Do you see the oil ports? Add a few drops of SAE 10 oil into each oil port. SAE 10 is a type of motor oil that can easily be purchased at a hardware or automotive store.
  • Schedule: Add a reminder to your calendar to add oil to the ports during the beginning of the warm months. Every year before the official A/C unit season begins, you can oil up the motor and prevent the motor from making this humming noise.

If you’re not sure where an oil port is, don’t worry. Your HVAC technician can easily fix this problem for you.

Loose screws

Loose screws can cause a rattling noise to occur in both the air handler and the condenser cabinet. This is because there are several parts of the A/C unit that vibrate while they work. Long-term vibration can cause the screws to become loose. You can fix this by locating the cabinet panel and tightening any loose screws. Use a screwdriver (not a power drill) to prevent stripping the screws.

Debris in the Outdoor Coil

If you hear a buzzing from your outdoor coil, you may have debris built-up on the coil. To remove the debris, take your garden hose and gently hose off the entire unit. If the buzzing noise continues, one of the aluminum fins may be bent. If you notice a bent fin, you can fix this on your own, but you must exercise caution and avoid using anything sharp to straighten it out. Instead, purchase a special device called a fin comb. This is an expensive tool that is made to straighten out bent fins.

When to Call the Professionals

Do you hear a harsh and grating noise?

Unlike rattling noises (which usually just means something is loose), a harsh or grating noise is cause for a call to the professionals. Turn off your air conditioning unit and call a professional.

Do you hear hissing?

Hissing can be caused by a leak, specifically leaking refrigerant. A leak of any kind should be handled by an HVAC professional. Do not attempt to fix a leak on your own.

Do you hear grinding?

Grinding noises coming from the motor are indicative of a fan motor issue. For instance, a bearing may be worn out. Your HVAC technician will be able to determine the cause of the grinding and if a worn-out bearing is to blame.

Here are a few other reasons to enlist the help of a professional:

  • You are not sure where the sound is coming from
  • You tightened the screws, but the rattling noise persists. Rattling not caused by loose screws may indicate a problem with the compressor.
  • You hosed down the outdoor until but you can still hear the humming
  • You think the aluminum fins are bent but aren’t comfortable straightening on your own

Let Us Help You

When it comes to heating and cooling, you’re never alone. If you’d like a professional diagnosis, we can get to the bottom of what is causing your air conditioner unit to make noises. If you live in the Baltimore area, contact us today at Farnen & Dermer Inc.