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Commercial Air Conditioning, Commercial HVAC, Preventive Maintenance Agreements

Get to the Bottom of Air Conditioning Noise

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We all want our air conditioners to be as unobtrusive as possible, while getting the job done. That’s why if air conditioners get loud, or start making strange sounds, it gets annoying in a hurry.

But not all air conditioning noise is equal. Some sounds indicate more trouble than others. How do you know if it’s a quick fix, something a service tech needs to take care of, or something you could just drown out by donning headphones and blasting your tunes?

Take a look at the types of air conditioning noise you’re likely to hear, and what it means about your HVAC.

The Whistling Air Conditioning Noise

If your AC keeps interrupting your workday with its whistle solo, see if you can track down the source of the theatrics. If the air conditioning noise you hear sounds like a whistle or a whine, that points to air flow issues. Get your ventilation checked for these probable causes.

  • The ducts don’t match the AC
    If you had parts of your HVAC updated or replaced, or if you had air ducts installed separately, then the ventilation may not be working with the rest of the system. The ductwork might not be big enough for the air flowing through them.
  • The filter’s clogged
    The air filter is meant to catch dust and particles in the air. But when it has reached its limit, it can impede the flow of air, causing air conditioning noise.
  • The ductwork is damaged
    Old ventilation pipes can develop leaks and cracks through which air escapes. A change in air pressure might be behind your AC’s musical, whistling debut.

The Air Conditioner That Won’t Turn It Down

If your AC has an affinity for high volume, it may be because of the way it was designed. Lower cost units are often less expensive because they skip the noise reduction features that higher end models have.

You might also have gotten a unit bigger than what you actually need for the space you have. That can generate excess air conditioning noise because it starts and stops frequently.

Related article: New York HVAC Systems: 8 Reasons Bigger Is Not Always Better

There are some ways to fine tune the design and save your eardrums from too much air conditioning noise.

  • If you’re near a busy street, you likely try to keep the quietest rooms away from the street side. The same method should be used when placing your AC unit. That way you put both traffic and air conditioning noise in one area of your space, allowing more quiet for the rest.
  • Further separate your “quiet spaces” from your AC unit by placing storage spaces, printer rooms or break rooms between them.
  • Use ductwork that directs air in a smooth, uninterrupted line. Twisted and turbulent airflow creates more air conditioning noise.
  • Use air return ducts. Air return louvers carry air (and noise) from room to room.

Related article: 4 Reasons You Need HVAC Design for Your Air Conditioning Install

The AC Shake, Rattle, and Roll

If your air conditioner is rattling and shaking more than a salsa dance team, it’s time to check out the problem.

Try to locate the specific source of the rattling air conditioning noise before you get another headache! Here are some elements that can cause your AC to bust some moves.

  • Stabilization (or lack thereof)
    If the racket’s coming from the AC unit itself, then it might not be placed stably on the floor surface.

Heads up DIY-ers, this isn’t one to tackle yourself. Remember the hazardous chemicals and high voltage electricity that need to be handled carefully. Save your talents for that IKEA bookcase, and have a professional handle this one.

  • Fan operation
    Also issuing from the AC unit, this sound indicates a worn out part in the fan. It could be the motor or the blades.
  • Loose ducts (or loose items in the ducts)
    The ducts that move air from your HVAC throughout your space should be tightly secured to the wall or ceiling to prevent air conditioning noise. Over time, they can become loose. If you find where a duct has come loose, it’s possible for you to secure it with a screwdriver.

If the duct itself is not loose, something could be loose inside it. Small objects sometimes find their way into ventilation, where they can bounce around like the inside of a maraca.

The Squeaking and Squealing AC

If your AC starts hitting higher notes than Mariah Carey, it may be voicing its complaint against a lack of maintenance. Here’s what could be behind that squeaky air conditioning noise.

  • Motor shaft bearings in need of oil
    Just like an old door hinge, parts of the motor can make a squealing sound if they are not properly oiled and start to get stuck. This is one air conditioning noise that’s easily taken care of with regular maintenance.
  • Broken blower belt
    The fan motor uses a belt that could have broken or slipped off the fan. Regular inspections can catch issues like this before they cause problems.

When an Air Conditioning Noise is a Red Alert

Out of all the unusual sounds your system could be making, there’s one pattern that you must respond to immediately.

If your AC is constantly running, AND it is blowing warm air, turn it off right away. This is a sign of frozen coils, which should be taken care of as you notice it to prevent more damage to your unit.

Air Conditioning Noise That Doesn’t Stop Going

There are lots of issues that make an AC run constantly, from frozen coils to blocked filters.

Your air conditioning keeps running until the interior has reached the set temperature. If any problem is preventing the AC from creating cool air, it will never reach that low temperature, and therefore never turn off.

Your AC should cycle on and off only as needed, so if you notice that air conditioning noise has become a constant background hum in your life, these are the details you should be concerned with.

  • Failure Alert
    When an AC refuses to turn off, it’s a sign of some interruption to its cooling cycle. This air conditioning noise could be the first sign of a larger problem.
  • Unnecessary strain on parts
    Too much use can cause the parts of your machine to wear out faster than normal, which will need replacing sooner rather than later.
  • Wasted money (and energy)
    Air conditioners draw a lot of energy, something you’ll see reflected in your power bills if it doesn’t turn off when it should.

While it’s tempting to think that just ignoring air conditioning noise will save you money, it can actually end up costing you more than just your sanity.

AC noise is your unit’s way of telling you that something has gone wrong. Pay attention to this cue and stop the noise before the problem that caused it stops your AC all together.

Neglecting maintenance can quickly add up to cost more than you might imagine. And it’s not only HVAC repair costs; poor HVAC performance can seriously hurt your business. To find out why preventative maintenance is a good investment, check out our guide to Calculating the Hidden Costs of Poor HVAC Maintenance.


Get the guide to understanding your HVAC System's hidden costs.