How to Reduce Noise from Outside Air Conditioner

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Air conditioners are a bliss, especially in the hot summer months.

The only gripe?

Air conditioners can be loud—which might disturb your sleep—defeating their entire purpose.

Of course, some might take the plunge and replace it with an entirely new quieter AC.

But in my opinion, it might not be a bad idea to use some DIY-trickery to try and reduce noise from your air-conditioning first.

Not to mention it will also help you save a considerable amount of money.

In this research, we’ll dive into some inexpensive yet efficient DIY ways of reducing noise from your AC.


Well, let’s dive straight into it!

Things You Will Need: At a Glance

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Sound Absorbing Blankets

Blankets made of thick and dense layers can help eliminate noise up to 65%; the most inexpensive method

Bamboo Wood Fence / Mass Loaded Vinyl (MLV)

Helps create a 4-sided fence to dampen sound; the most effective method

Foam Rubber

Helps with noises that primarily occur due to vibrations

Weatherstripping Tape

Fixes gaps in doors and windows to eliminate noise coming from outside AC

Door Sweep

Fixes the gap at the bottom of your door to reduce noise leaks

Green Glue

Fills the holes in the wall to prevent noise from leaking in

Note: If DIY is too much work for you, you might also want to consider checking out my recommendations on the quietest window AC and the quietest portable air-conditioner. I have spent dozens of hours researching the most efficient and budget-friendly units.

1. Use a Sound-Absorbing Blanket

Since this is the most inexpensive option, I’d recommend you to get started with a soundproof blanket first.

It helps absorbs a considerable amount of noise and prevents it from emanating to other areas. They are thick and have dense layers. The vibrations enter this inner dense portion and get dampened. In my experience, it can help reduce noise by up to 40%.

They’re easy to install, thanks to the hook and loop closures.

The Audimute sound-absorption sheet is my favorite choice. It comes with a Noice Reduction Rating (NRR) of 0.85 and eliminates up to 65% of outside noise.

If you’d like to consider more options, I recommend you check out my list of the best acoustic blankets you can buy right now.

Here are a few tips you can use to hang your acoustic blanket:

  • Nail the blanket on the wall using 10-penny nails, which are about 3 inches long.
  • You can also use a heavy-duty staple gun.
  • Use industrial-strength adhesive if nailing is not an option.
  • Use mounting putty at the edges for a temporary solution.

2. Install a Fence (Using Bamboo Wood)

Optimum Dimensions for a Fence Around an Air Conditioner
Optimum Dimensions for a Fence Around an Air Conditioner

Installing a fence is more challenging than using an acoustic blanket, but it’s also much more efficient.

The general idea behind this is to create a fence high enough to muffle the noise coming from your AC.

So which material should you use to build the fence?

While you can use any material you want, I highly recommend a couple of materials—bamboo wood and Mass Loaded Vinyl (MLV).

This bamboo wood fence from Backyard X-Scapes is of commercial quality and is UV and water-resistant.

Mass Loaded Vinyl, or MLV, is a heavy sheeting material impregnated with metal particles to increase its mass. It is a perfect material to use as a sound barrier on your fence. I like this MLV from TotalMass which is highly effective in blocking noise and is easy to cut and work with.

Whatever material you chose to go with, it’s always recommended to go for a 4-sided fence as 2-sided ones can cause sound reverberation.

Here are a few tips to help you install MLV on your fence:

  • Use adhesive green glue to fix the MLV to your fence.
  • Alternatively, you can also screw the MLV to the fence
  • Stitch it widely across the fence as is extremely heavy and might fall off of your fence

Alternatively, you can also call a professional to do this process for you—and it shouldn’t take more than a few hours.

3. Build a Stable Base to Eliminate Vibrations

If vibrations from your AC are the culprit of loud noise, this step might do the trick.

Here’s how:

When the base of your AC is in contact with a rough surface, the vibrations travel through the base and the sound is amplified.

You can use this foam to create a suitable base that can help attenuate the sound of the vibrations.

Also, ensure that your AC is resting on a stable surface otherwise it may be wobbly—and create more vibrating noise.

4. Eliminate Water Dripping Sound

Do you dislike the sound of water dripping from your air conditioner?

Here’s an easy way to combat this:

  • All you need to have is a hose and a plastic bottle
  • Attach the hose to the hose of the AC
  • Channelize the water to the plastic bottle


You should now be able to enjoy fresh air from open windows without having to listen to the water dripping sound.

5. Move Your AC to Other Location

You should consider moving your AC unit as far as possible from your bedroom or living room.

Of course, it’s not possible for everyone to do this—but if you can—you should.

You might even try placing it towards the back of your house.

6. Schedule Regular AC Maintenance 

Clogs, wear and tear, or components that are not functioning properly might also cause unnecessary noise from the AC.

Keeping the AC well-maintained not only goes a long way in helping to minimize noise, but also provides multiple benefits.

A tuned-up HVAC system means less hassle of repairs, a longer equipment life, and safer equipment operation in general. To prevent surprise breakdowns and to keep your HVAC system operating at peak efficiency, it’s important to learn the ins-and-outs of its maintenance. 

HVAC maintenance tips checklist DIY Soundproof Expert

Checks You Should Do Right Away

  • Cut any plants or grass that are around 12 inches of your condenser.
  • Keep the heating registers & vents free of dust and pet hair.
  • Remove any drapes or furniture that might be blocking the supply & return registers.

Monthly or Seasonal Checks

  • Every 3 months, replace the air filter. You might need to do it monthly if you have pets in your home.
  • Every 3 months, clean the condensate drain line. You can pour a cup of bleach in the drain line near the AC unit to kill any algae formed in the pipe.
  • Every month, inspect the insulation of refrigerant lines. If the insulation is missing or looks deteriorated, replace it immediately.
  • Shut down the humidifier at the end of each heating season.  

Annual Checks

  • Do a complete HVAC maintenance check done by a certified professional twice a year—preferably in the spring & fall.
  • Clean your vents and registers at least annually to help them circulate air as efficiently as possible.
  • Clean evaporator & condenser coils once or twice a year.
  • Replace the battery in your home’s carbon monoxide detector annually.

7. Soundproof Other Areas Where the Noise is Coming From – Windows, Doors, etc

How to Install a Door Sweep
How to Install a Door Sweep

This might sound quite obvious to some—but I’m surprised how many people still ignore this.

Since the AC is outside your home, the noise may leak in through various parts of your house like the windows, doors, etc.

You can reduce this noise by simply by soundproofing your window, doors, and walls.

One obvious benefit of this is that you will not only reduce noise from your AC but from other sources too.

Here are a few tips to help you get started:

  • Gaps and crevices in doors and windows can be mended easily using a weatherstripping tape. This weatherstripping tape is flexible, resilient, and waterproof.
  • If the noise enters from the gap at the bottom of your door, you can try installing a door sweep. The Baining door sweep is durable and can be installed easily on doors of different materials such as wood, metal, plastic, etc. There has been a drastic decrease in the disturbance pervading in my room since I installed this.
  • Besides this, you can also go for soundproof curtains and acoustic panels which are also great sound-blockers.
  • If you have holes in the walls, you may apply this green glue which is pretty effective at filling those gaps to prevent sound from leaking in.

If you’d like to explore the above tips with detailed instructions, I’d recommend you check out our individual guides below:

Frequently Asked Questions (FAQs)

1. Why Is My Air Conditioner So Loud Outside?

Here are some common reasons why your AC might be noisy:

  • Normal wear and tear of different parts
  • Failing motor
  • Loose circuit connections
  • Damaged capacitor
  • Arcing or electrical current escaping the expected path leading to sparks
  • Accumulation of debris on the parts of the system
  • Bad expansion valve
  • Loose-fitting air filter
  • Fault in the fan motor or blower motor

2. How Loud Should My AC Be?

Generally, air conditioners emit about 35 to 85 decibels of sound. However, the loudness of the AC depends significantly on the brand and model.

As a general rule, old versions generate much more noise compared to newer models.

Most of the latest ACs come with VRF technology (Variable Refrigerant Flow) which makes them pretty quiet.

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