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Why is my AC making a loud noise?

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air conditioner noise

Rid yourself of a noisy air conditioner

The hot weather has hit and the cool air provided by your air conditioning system gives you welcome relief, but the noise coming from your air conditioner is quite another story. When your system was initially turned on, you thought the air conditioner noise would go away, but it hasn’t.

A noisy air conditioner is not only disruptive to the calm in your home or business, it can be symptom of an inefficiently and an improperly operating system that is headed for a breakdown.

The most common causes of air conditioner noise are related to:

  • damaged duct work or poor duct design
  • clogged filters
  • loose parts
  • bearings and belts
  • electrical issues
  • fan problems
  • coil damage

Let’s take a look at the reasons behind the specific air conditioner noise you may be noticing, and what can be done to quiet your noisy air conditioner down.

Top reasons for a noisy air conditioner

Although all loud air conditioner noise is not exactly music to the ears, different noises stem from different air conditioner problems. An air conditioner whistling while it works may make you grumpy, but one that squeaks will not make you happy either. And all this air conditioner noise could end up making you sleepy if you don’t call in the air conditioner doc to cure your air conditioner ills and give you the quiet you need for a sound sleep.

Whining and whistling

Is your air conditioner plagued by one of the woeful W’s – whistling and whining? These annoying sounds could signal airflow problems. Here are some of the reasons for these vexing ventilation problems causing your noisy air conditioner:

  • Incompatible ducts and unit. If your HVAC unit parts have been replaced or your air ducts installed at a different time, the ventilation might not be running smoothly with the rest of the system. The ductwork might be too small for the air blowing through the system, which could result in a whistling sound.
  • Damaged ducts. It’s not unusual for ductwork to develop cracks and leaks over the years. Air can escape through these openings and produce a whistling sound.
  • Clogged filters. Air filters, which are designed to catch dust and other particles and contaminants, will become full at some point. When the filters reach capacity, airflow can be blocked, which will cause air conditioner noise.

Besides whining and whistling, there are other noises that are not music to your ears.

Shake rattle and roll

These sounds typically emanate from loose air conditioner parts. Most commonly parts of the system subjected to a lot of movement, such as motors, can come loose. Ducts can also come loose. Your air conditioner unit itself can be the culprit behind the clatter and may need to be stabilized.

Though you weekend warriors may be tempted to try and steady your unit, it is advisable to call in an HVAC professional in order to avoid the dangers of contact with hazardous chemicals and high voltage electricity.

Learn more: Air Conditioner Maintenance Tips for the DIYer

3 S’s (squeaking, squealing and screeching)

You might want to have an HVAC professional look at your systems compressor and fan motors. These types of sounds often are the result of unlubricated bearings or slipped or damaged blower belts.

You’ve got a screw loose

When an air conditioner is operating continuously, it is also vibrating nonstop. All this vibration can cause loose screws which can be the source of your air conditioner noise. Your noisy air conditioner could be the result of one or more of the screws in panels shaking loose. Mounting screws, which hold your unit in place, may have also vibrated loose. A screwdriver is all it might take to silence the rattling.

What’s the buzz?

Most of the time, a buzzing sound comes from an electrical problem. If you are hearing a clicking sound, it could mean your systems relays or contactors are failing.

Not a fan of air conditioner noise?

In order for an air conditioner’s fan to run properly, it must be maintained routinely and kept clean. A rattling or humming fan, might need a good cleaning. A worn-out part in the fan, problems within the fan motor or bent or shifted blades could be the source of air conditioner noise.

Refrigerant leaks

A refrigerant leak may be the cause of your air conditioner noise. If you are hearing a hissing noise,
your system could have a refrigerant leak. Refrigerant levels are checked regularly if you have a preventative maintenance plan with a reputable HVAC company.

Coil problems

Dirty or frozen coils may be the culprit responsible for be behind your air conditioner noise. If coil fins become clogged with dirt, noise is the unwanted result. Bent coil fins can produce a humming sound. Clogged coils will cause your system to work harder and longer, which will increase your energy bill and eventually will lead to a system breakdown.

Just because the noise is inside our building, do not overlook examining your outside condenser unit. It is not unusual for twigs and other debris to get stuck in the condenser unit’s fan. Make sure the area is swept clean of dirt and debris.

Learn more: AC Losing Its Cool? Try Air Conditioning Coil Cleaning

Poor system design

Have you been plagued by air conditioner noise since your system was installed, with the unit constantly turning on and off? If so, the system may be too large for your space. Or, it may not be outfitted with high quality noise reduction technology.

Stop the racket with routine preventative maintenance

Many noisy air conditioner problems could be prevented with regular preventative maintenance undertaken by a reliable HVAC company like Arista Air. Your air conditioner noise is more than just an annoyance. It could be costing you money in terms of operational inefficiency. And it could lead to an inconvenient system breakdown in the hot summer months which requires an expensive repair.

Repair or replace your noisy air conditioner?

When you’re faced with a costly repair estimate to fix your noise problem, you now have another problem: how to decide if it’s worth fixing?

It would be advisable to invite an HVAC company in to assess your noisy air conditioner problem and make recommendations. There are many factors to take into consideration before making a repair or replace decision, including the age and condition of the system, its repair history and the extent of the current damage. Also, if it uses R22 refrigerant (Freon), which is being phased out soon, that should impact your decision.

To learn more, download our helpful guide: Repair or Replace? A guide to making an informed choice when your HVAC system is down.