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​​How to Stop Air Conditioner Vibration (Complete Guide)

A vibrating air conditioner can be annoying, disruptive, and expensive. Knowing what’s causing the loud noises can help you soundproof, secure, or repair your appliance. Contrary to popular belief, there’s no AC that vibrates without a problem present.

To stop air conditioner vibrations, follow these tips:

  • Secure the unit
  • Clean the AC
  • Soundproof the air conditioner
  • Fix the compressor
  • Lubricate the motor
  • Tighten the ducts and vents
  • Get a new fan motor
  • Maintain the ambient temperature
  • Try new fan blades

In this article, we’ll show you the step-by-step process to help you stop your air conditioner from vibrating. We’ll also talk about what causes these noises and how you can quickly diagnose them.

Tighten All of the Nuts and Bolts

One of the main reasons air conditioners vibrate is because they’re not secured properly. The motors, fans, and other components of an AC cause tiny vibrations that slowly loosen the nuts and bolts securing them. As these parts loosen, they’re much more likely to vibrate the metal and make a loud rattling sound.

Outdoor air conditioners often have several bolts holding them to the ground. They’re designed to keep the AC in place, stopping the wires and pipes from breaking. Gradual movements pull and vibrate the unit, so it’s best to tighten them annually. You can use a wrench or Phillips screwdriver, depending on the make and model.

Indoor and window air conditioners should have their seals and bolts regularly inspected, too. Tightening the seals and screws prevents unwanted vibrations. We recommend tightening all of the screws, unions, and other components throughout your air conditioner. Anything in, on, or around the appliance can vibrate if it’s loose.

Note: If the screws are rusted or stripped, it’s best to contact an expert. Breaking the screws can jam them away from the air conditioner, causing the AC to shake and rattle.

Clean Inside the Air Conditioner

A dirty air conditioner can produce foul odors, loud vibrations, and so on. Cousins Air explains a deep-cleaning involving the coils, lines, and pans can make a significant difference. If you’re tired of your air conditioner’s vibrating sounds and you’ve tried the other suggestions, a cleaning session might be in order.

So, how can you clean your air conditioner? Follow this process:

  • Clean the coils. Use Arm & Hammer Air Conditioner Spray on the coils to remove grime and debris. Bring your indoor AC coil outside and spray a thin layer of this quick-cleaning, biodegradable solution on it, then rinse it off with a hose. You can follow the same steps with an outdoor AC by removing the top panel and cleaning the coil.
  • Vacuum the drain line with a wet vacuum. Wrap a towel around the open end, attach the vacuum over the towel, and turn it on for a few minutes. You’ll notice plenty of dirty water and potential clogs that could cause vibrations when you use the air conditioner. These clogs also contribute to musty odors in your AC.
  • Use a handheld air compressor to remove dust from the wires and vents. This step prevents unwanted noises and keeps the air clean and fresh. You could also replace the AC filter if it’s old and dirty. A debris-covered filter will bump and vibrate when the air conditioner is on.

Use Sound Reduction Tools

Air conditioners aren’t known to be quiet, so even a brand-new unit can make some noise. If you want to eliminate the vibrations and rattling sounds, you can use various sound reduction tools. Below, we’ll break down a few options you can try to quiet your air conditioner for good.

  • Bright Hub Engineering suggests using sound pads for your air conditioner. Whether it’s on the roof, in the window, or outside, you can try the LBG Products Anti-Vibration Pads. These pads are designed to keep your air conditioner in place while absorbing the rattling. They’re 2” x 2”, but the company also sells bigger sizes.
  • Try sound-deadening blankets. These sheets are designed to prevent sound from coming into and going out of audio studios, conference rooms, and so on. However, you can place one under the air conditioner to limit the vibrations going through the walls. A soundproof blanket can be cut to size.
  • Brace or tighten loose components. If you can’t tighten the screws and other parts while waiting for a maintenance worker, you can use electrical tape to stop everything from vibrating. Most vibrating or rattling noises on an air conditioner come from loose bits and pieces that can be secured to reduce their sound output.

Replace the Compressor

An air conditioner compressor is responsible for handling the coolant. Without it, your AC wouldn’t lower the temperature in the house. A loose or malfunctioning compressor rattles the system because it can’t compress the coolant. While it might be tempting to DIY the repair, we highly suggest getting a professional to do the job.

Note: Compressors contain coolant, a chemical that can cause severe damage when mishandled.

Replacing a compressor in an air conditioner typically consists of the following steps:

  1. Turn off the power going to the air conditioner.
  2. Locate the compressor in the back of the air conditioner where the coolant flows.
  3. Disconnect the wires from the compressor.
  4. This step depends on the AC’s make and model (some must be sawed out, while others can unscrew and slide out).
  5. Add the new compressor as recommended by the manufacturer.
  6. Tighten the old wires and screws to the compressor, turn on the power, and test your work.

Again, this isn’t a task that should be handled by anyone other than an HVAC technician. Making mistakes while repairing or replacing a compressor can cause a hazardous scenario that ruins your air conditioner.

Lubricate the Fan’s Motor

Sometimes, your air conditioner’s fan could be the culprit. It runs every time the air conditioner is on. After several years of continuous use, the metal-on-metal friction takes its toll. Why get a new fan motor when all it might need is a little bit of oil? The good news is we’ve provided the simple solution below.

Here’s how you can oil the fan’s motor:

  1. Turn off the circuit breaker going to the air conditioner. There are far too many wires in an AC to leave them live while working on the motor.
  2. Remove the top panel from the air conditioner. You’ll likely need a flathead screwdriver, but some air conditioners require Phillips screwdrivers.
  3. Flip over the top panel to reveal the fan. If the fan is inside of the air conditioner, now is the time to remove the wires and set them on top of the panel to make them easier to work on.
  4. Place a few drops of the 3-in-1 Multipurpose Oil on the base of the blade. The drops should pour into the base where the motor connects to the fan blades. Manually spin the blade a few times to evenly coat it with oil. This oil lubricates and removes rust, preventing unwanted sounds while limiting wear and tear.
  5. Replace the fan and tighten the top panel to secure the air conditioner, then turn on the circuit breaker and listen for the sounds.

Swimming in the Deep shows a helpful guide here:

Tighten Loose Ducts and Vents

It might seem like your air conditioner is causing the vibrations, but it could be the vents or ducts. Walk around your home and listen for the sounds, checking where they’re louder or quieter. If they seem noisier in a specific location, there might be a loose vent or duct.

As the ducts and vents move air throughout the year, they’re susceptible to loosening. You can tighten the vents by replacing the screws every few years. These screws rust and strip, making them rattle every time the air conditioner turns on. The vent covers might also need to be replaced, so keep an eye out for misshapen parts.

Fixing a loose duct can be as easy as tightening the retaining brackets. You can often find loose ducts in the attic or basement. However, if you can’t access the loose or broken duct, you’ll need to hire a professional. They’ll be able to diagnose the problem to ensure the duct is the cause. When it’s time to replace the duct, you can get a warranty on the work.

While you’re inspecting the vent covers, ensure the air conditioner’s filter is facing the right way. Check the arrows on the filter’s side. They indicate which direction it should face. If they’re going the wrong way or the filter’s cover is loose, you’ll hear a vibrating sound.

Replace the Fan Motor

If your air conditioner is vibrating, it might be the fan’s motor. Every air conditioner has a fan to push and pull air through it. When the motor’s bearings wear down, they screech and rumble. You’ll hear the noises throughout the house if the damage is severe. Fortunately, replacing an AC fan motor is relatively straightforward.

Here’s the method:

  1. Turn off the circuit breaker connected to the air conditioner.
  2. Remove the top panel of the unit to reveal the fan’s motor (for outdoor AC) or unscrew the front panel to access the motor (for indoor AC).
  3. Use a screwdriver to remove the four mounting bolts from the air conditioner’s fan motor.
  4. Pull the wires out of the fan’s motor (we recommend taking a picture of the layout beforehand, so you know where the wires connect to the new motor).
  5. Set the old motor aside and install the new one by attaching the old wires and mounting bolts.
  6. Hook the fan back onto the motor if necessary (some models disconnect while other models are permanently attached).
  7. Mount the top or front panel onto the air conditioner and turn on the circuit breaker to test your work.

Air conditioner fan motors don’t last much longer than a decade. If you prefer video tutorials, review these guidelines by HVAC School on YouTube:

Let Your AC Maintain the Temperature

Air conditioners work their hardest when changing the temperature drastically. For example, if it has to increase or decrease the temperature by 20 or more degrees Fahrenheit, it’ll roar and work much harder. To keep your air conditioner from overworking and wearing down prematurely, you could maintain it at a natural temperature throughout the year.

Many people find 75 degrees Fahrenheit (24 Celsius) to be a comfortable, relaxing temperature. Keeping your air conditioner in this setting will help it maintain the comfort you desire without working overtime. It also means it won’t turn on as often, limiting the amount of noise it produces during the day.

Installation service fix repair maintenance of an air conditioner outdoor unit, by cryogenist technican worker evacuate the system with vacuum pump and manifold gauges tablet in blue shirt and baseball cap

Balance the Fan Blades

According to SFGate, unbalanced fan blades can cause frustrating noises coming from the air conditioner. If the blades are slightly off, they’ll wobble and loosen the screws. As we mentioned earlier, loose components create all sorts of unwanted sounds.

To balance the fan blades, keep these suggestions in mind:

  • Always turn off the appliance before balancing the blades to avoid injuries.
  • Unscrew the blades, realign them, and screw them back into the motor.
  • Lubricate the blades and motor whenever you balance them with the aforementioned oil.
  • Replace stripped, corroded, or rusted bolts since they won’t secure the blades for too long.
  • Consider getting new blades from the manufacturer if they’re warped or damaged.
  • Wipe each blade to remove grime, dust, and debris that can cause them to vibrate.
  • Ensure the blades are facing the correct direction, as shown in the user’s manual.
  • An old fan motor can continuously force the fan blades out of alignment, which means they might need to be replaced.

Whether or not the air conditioner’s fan blades and motor are the cause of the problem, they should be inspected annually to prevent long-term problems. Lubricating oil and new bolts can make a world of difference by increasing their longevity and performance. As with most HVAC repairs, regular maintenance prevents expensive replacements.

Author

  • Steve Rajeckas

    Steve Rajeckas is an HVAC hobbyist with an avid interest in learning innovative ways to keep rooms, buildings, and everything else at the optimal temperature. When he's not working on new posts for Temperature Master, he can be found reading books or exploring the outdoors.