What It Means When Your Air Conditioner Starts Making A Strange Noise

image of homeowner covering ears due to loud air conditioner noises

When machines make sounds, it’s certainly not surprising. Your home isn’t absolutely silent when you’ve got your refrigerator, dishwasher, washing machine, and fans running. Even air conditioning systems produce a faint humming noise. However, loud noises, like when an air conditioner rumbles or clangs when starting, simply aren’t normal. If your air conditioner makes loud noise when starting, take a minute to find the source. It could be the sign of a far larger problem with your air conditioner. This article will talk about the common causes of a loud air conditioner as well as offer a few possible solutions.

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Your Air Conditioner Makes Loud Noises When It Starts Up

You may hear loud noises when your AC unit is first turned on. Listen to these sounds closely because there are several types of noises that cooling units can make. Each sound points to a specific issue that needs to be investigated and resolved. This isn’t an issue that you should fix on your own. It is far better to contact an HVAC technician instead to get help.

Different Noises That Air Conditioners Can Make

Read on to find out more about strange air conditioner sounds.

1. Banging & Clanging Air Conditioning Sounds

image of an air conditioner compressor

Your air conditioner has an outdoor blower motor that pushes air into your home. If the blower motor gets damaged, it will likely make an odd noise or two while in operation. Parts may come loose and start hitting the cage. Thermal expansion, moving debris and even damper movements could be the culprit too.

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2. A Persistent Clicking AC Unit Noise

Clicking air conditioning sounds are a sign of electrical problems. You might try to start your air conditioner up, but nothing ever happens. This is also a problem that should only be handled by professional HVAC technicians. They’ll take a look at the thermostat, compressor, and capacitor.

3. Your Air Conditioner Is Screeching

image of an air conditioner fan and condenser

If you hear a metal-on-metal noise, then it may be the result of fan motor bearings that are broken or worn. This isn’t exactly an emergency; however, it is still a good idea to take action before the problem becomes worse. Have an HVAC professional take care of it before you start using your A/C again.

4. The Cooling System Is Pulsating

Low-level pulsating sounds can be expected as air flows through these systems. However, the pulsating noises that come from the outdoor unit should not be audible inside of your home. If you can hear these, the unit may have broken fan blades or debris like twigs floating around inside.

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5. Your Air Conditioner Is Whirring

Whirring cooling system noises indicate a mechanical problem within the air conditioner. This sound can occur both inside and out. Among some of the more common causes of whirring noises are faulty blades, broken belts, blow fan motors, and bad bearings. Turn your air conditioner off right away and contact a local HVAC company for repairs.

6. The Air Conditioner Is Humming or Buzzing

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If the outdoor air conditioner starts making an audible humming noise, then find out if it has trapped debris. Leaves, flowers, and branches are able to get in through various holes. Take these out right away. Buzzing could also be an indication of a worn fan.

7. The Air Conditioner Is Rattling

Rattling is frequently the result of air conditioner parts that have loosened as the result of vibration. Check the bolts and screws around your air conditioner. These may need to be tightened up. It’s a good idea to additionally change the AC air filter and clean the unit’s coils. Better still, contact an HVAC company to schedule professional air conditioner maintenance.

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Common Ways in Which HVAC Contractors Deal With Air Conditioner Noise

1. Straight and Clean the Unit’s Coil Fins

To improve the efficiency and overall performance of your air conditioner’s coil fins, be sure to keep these clean. Contact an HVAC company to set up annual tune-up services for your air conditioner. During these visits, your technician will straighten the coil fins with a fin comb – they can also use a vacuum with a brush attachment to clear out all dirt and other debris.

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2. Tighten up Any Loose Screws

Given just how many moving parts your air conditioner has, it is normal for these units to vibrate slightly while in operation. However, over time, this vibration can cause screws to loosen. It may even get to the point where you hear an audible rattling noise whenever the unit is on. Regular HVAC maintenance will give technicians the chance to tighten up loose screws.

3. Debris in the Blades Should Be Removed

air conditioner condenser fan close up

Take a look inside of the air conditioner cabinet by opening it up. If you spot any debris, take it out as soon as you can. Check for foreign objects near the fan blades. This is a quick clean-up that homeowners can handle themselves. However, for a more thorough cleaning to enhance efficiency and comfort, call a reputable HVAC contractor.

4. Bent Blades Should Be Straightened

After you’ve taken out all dirt and debris, take a minute to inspect the blades to see if they have any issues. Blades that are uneven can be bent back to their rightful shape. Contact an HVAC company if you see bent blades. They can take care of this issue carefully to prevent problems from worsening. They will carefully inspect each and every blade and put them all back in order.

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5. The Motor Can Be Lubricated

Screeching noises may indicate that the motor needs to be lubricated. Lubricating this component is something that your technician will do during tune-ups – this way, screeching noises never occur. They’ll use the correct oil for the job so that any existing sounds are eliminated. They can also add oil to the ports at the base of the AC unit’ fan motor.

What Homeowners Can Do to Address Loud Air Conditioner Noises

Continue reading to find out what you can do to deal with strange noises coming from your cooling system.

1. Inspect the AC Unit & Check the Outdoor Fan

Before you take any other actions, start by checking the condenser fan inside of your air conditioner’s outside unit. If it still rotates, assess how its blades are spinning. If these appear to be off-balance or come in contact with anything, it could be that the casing has debris in it. Check the refrigerant piping and coils too. If you aren’t sure what you’re looking for, let a professional handle this job. When in doubt, always let an HVAC technician take care of things for you.

2. Change Your Air Conditioner’s Air Filter

replacing HVAC filter

This is an important step for all homeowners to take. Air conditioners cannot perform like they should when their filters are clogged and dirty because dirty filters impede airflow. Your air conditioner will struggle constantly, and it will likely produce humming sounds. Check your air conditioner’s air filter at least once each month and replace it as needed.

3. Do Some Cleaning Around the Outside AC Unit

Things right near the outdoor air conditioner unit can cause problems too. Debris can find its way into the slits. To be safe, turn off the air conditioner before opening the case. Take the top grille off and remove any fallen objects. Close it up tightly.

4. The Run Capacitor Should Be Checked

Once the unit has been cleaned, turn it back on to see if the fan is spinning. If it won’t move, try jump-starting it by using a long stick to move the blade until there’s enough momentum. If the blades begin to spin, your run capacitor is likely broken.

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5. Take a Look at the Indoor Air Handler

The problem may not lie with the outdoor unit. If you’ve finished up your outdoor inspection, go ahead and take a look at the indoor air handler. Check for ice build-ups or coil fins that are vent. With icing, turn off the power so that it can thaw, and then allow it to dry completely before turning it back on.

6. Contact an HVAC Company

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There are a lot of things that homeowners can do on their own to address and prevent problems that cause air conditioner noise. However, there are things that untrained individuals simply cannot take care of on their own. If you still hear a strange noise after you have gone through this checklist, be sure to schedule a professional AC service.


How to Prevent Strange Air Conditioner Noises

1. Have a Noise-Limiting Barrier Put In

Loud air conditioner noises can make it hard to hear yourself think. Too much sound during AC operation can make it hard to sleep. You can install a noise-limiting barrier to reduce excess sound. A noise-reducing fence or a sound blanket is perfect for this. However, ask your HVAC contractor before completing this.

2. Have Routine HVAC Maintenance Performed

Schedule annual HVAC maintenance. Technicians can spot issues while they’re still minor. They can take immediate steps to keep things from spiraling out of control. They can also thoroughly clean your air conditioner so that you don’t have to. These measures will limit the likelihood of strange sounds developing.

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3. Contact a Licensed HVAC Professional

When your air conditioner starts making strange sounds, call HVAC professionals in right away. Don’t neglect or ignore these issues. It is far more cost-effective to deal with minor problems early-on than it is to wait for cooling system failure to occur.



Be mindful of your air conditioner. It will let you know when something is wrong by producing distinctive sounds. HVAC manufacturers take diligent measures to limit unit noises. You can get an idea of which noises are normal by observing your air conditioner. If something is awry, try to find out what the problem is. Call a licensed professional when advanced air conditioner repairs are needed.

Call Hart Home Comfort Today For Any Air Conditioning Requirements

hart-logoHart Home Comfort will provide excellent heating and cooling service to clients in Nassau County, Suffolk County, and Queens, New York. We make sure you will get only a competent, certified technician that provides you with outstanding HVAC tune-up service, timely repairs, excellent installations, and the right replacements. Our technicians have both the knowledge and the expertise to service your home’s HVAC system the right way.

Hart Home Comfort guarantees competitive costs for heating and cooling services. Our maintenance services are sure to improve your home’s comfort, amplify your efficiency and even reduce your home’s heating and cooling costs. If you require an HVAC repair or even a replacement system, let us recommend the ideal one for your space while working within your budget. We ensure our work and work hard toward making sure you’re satisfied with every aspect of our service. To book an air conditioning unit tune-up or schedule your service appointment, please give Hart Home Comfort a phone call today. Ask us about our free estimates.

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