All air conditioning units will generate some type of sound. The noise can be categorized as either structural or airborne. Let’s go through the different types of noise you may be hearing, and what sounds may require professional attention.

Structural Noise

Structural noise is sound energy that travels through solid material that you feel as vibrations. In this case we’re talking about vibrations transmitted from the air conditioner into your home or office. This is most often a problem with wall air conditioners, air conditioners placed on the roof, or units that are on a wood platform and attached to the house. Stop AC vibration noise by decoupling the unit from whatever it’s vibrating against, so that the hard surfaces don’t come into contact with each other.

Airborne Noise

AC units have a lot of noisy parts like the fan and the compressor. Airborne noise consists of all the annoying sounds it makes. Sometimes the noises are mechanical in nature, and sometimes the noises are just common air conditioner noises. To stop this noise, you need to create a barrier to block the path of the sound and install an outdoor absorptive material to keep noise from reflecting off surfaces (like walls) surrounding the unit.

For all those uncommon sounds, it's a good idea to have a professional come look at it (check out our sounds list below for more suggestions). Here's a quick checklist of reasons you might hear more than just your regular AC unit sounds.

How Old is Your Unit?

Air conditioning units have changed over the years, and as newer models come out, you may find that an older unit is just . . . louder. Repacing your unit is an option and might be necessary if it's getting very old. For all other issues, building an air conditioner sound barrier will help you avoid replacing an old-but-not-too-old unit.

Is Your AC Unit Dirty?

Like we just said, the fans are usually the other noise source. Cleaning the blades can often alleviate some balance issues to make your fan a little bit quieter. Dust and dirt can often collect on units, so regularly maintain them longer life and better performance.

Have you Checked the Compressor?

Compressors are one of the two noisiest parts of an AC unit along with the fan. If you compressor is burnt out, it will be louder than a brand new compressor.

Is Anything Loose?

Generally, you can hear loose parts, but it's always a good idea to get a professional out there to look at your unit.

Alright, so there are a lot of types of noises an AC unit can make. If your unit is operating normally, the next step is treating the structural or airborne noise that you want to reduce. Let’s walk you through a few strategies from isolating the unit to building a physical barrier. You may need to use a combination of these approaches, as many units generate both structural and airborne noise. Here are your different steps you can take to soundproofing an air conditioning unit:

How to stop AC Vibration: DECOUPLE THE AC UNIT

Air conditioner units that are on the roof or attached to a wall often have vibration problems. You need to decouple the air conditioner from your building's structure with the use of 100% rubber vibration isolation pads like our Super W pads or an isolation mount designed for heavy machinery. This is recommended for an average residential unit. If you are looking to treat a commercial unit, give us a call and we can offer solutions using neoprene isolation mounts.

Air Conditioner Noise Reduction for Airborne Noise

There a few different methods of reducing airborne noise from your AC unit. If you haven't placed your AC unit yet in the case of a new build, consider placing it away from bedrooms and main living areas, and avoid windows and doors (they're the most prone to noise leaks).

Install a Fence

Installing a fence is a great way to soundproof your AC unit. It's fairly common to build a soundproof fence to improve the efficiency the fence. When building a fence around your unit, here are a few things to consider:

1. Build it high because sound radiates outward through the air, so to block it effectively, extend your fence 1.5 to 2 times the height of the unit. Two times the height is recommended.
2. Extend the fence either around your unit or well past it to stop the sound from flanking the sides. Rule of thumb is to extend the fence 4 times as far as it is close to the unit. For example if the wall is 1 foot from your unit, it should extend 4 feet past it.
3. Build it close to the air conditioner unit. The closer the fence is to the AC unit, the more sound it will be able to block. Be sure to leave enough space for ventilation.
4. Create an airtight fence. Sound moves like water and can get through the smallest holes. You shouldn’t have any gaps in your fence. 
5. Use a dense material. Dense materials are great at sound blocking, which is why we recommend using an MLV product as a sound barrier. You can hang our Luxury Liner™ Reinforced Mass Loaded Vinyl Roll or our Luxury Liner™ E84 Class A MLV Roll that are both UV stable with exceptional tensile strength making them the perfect MLV for building a dense, outdoor barrier.
   1. Alternatively, line your fence with charcoal BlocknZorbe™ for a sound blocking and absorbing solution.
6. Add absorption to reduce reflected sound off your fence. If you don't use BlocknZorbe™, our Quiet Quilt™ Outdoor Acoustic Blankets are dense enough to block some sound on their own, and they're great for absorbing echoes.

Build an Air Conditioner Sound Barrier

For the most effective barrier, we recommend not just building a fence, but creating an enclosure all around your unit, similar to building soundproof pool pump box. You can cover 3 sides, but for optimum performance, cover all 4 sides. We recommend getting one of our outdoor sound blankets to stop sound from travelling out to your backyard, pool, or neighbor's yard. Similar rules to building a fence apply. The barrier needs to be tall, wide, airtight, and dense.

Use Quiet Quilt™ Outdoor Soundproof Blankets with MLV sewn in and an absorptive face to counteract any reflected sound. They can be hung on their own system or attached to a fence. You can also use one of our reinforced mass loaded vinyl products, but you may get some reflected sound. Building a top that is a slanted roof with an opening facing away from your home will allow ventilation for your unit and direct the noise away from your house.

AC Compressor Sound Blankets

If you find that you have a noisy compressor, you consider getting a sound blanket for AC compressors. Check in with your AC unit manufacturer to see if there is a safe, recommended blanket for your compressor. These can make a big impact on you quietness of your AC unit startup, but you want to make sure it's manufacturer recommended because they can cause your unit to overheat and shorten the life of your AC unit.

Learn more about how to use AC sound blankets in this article!

Soundproofing Your Home from noisy AC Unit

Soundproofing immediately around the air conditioning unit is the most cost-effective way to reduce noise, but in some situations you'll need to consider soundproofing the house itself. The most common path for noise from an air conditioner positioned outside a bedroom to get into the home is through the window. There are multiple ways to soundproof a window, and huge range in the amount soundproofing a window costs. When it comes to soundproofing a wall, the window is typically the weakest point due to its lower STC rating. You may also need to soundproof your ductwork.

By adding Fantastic Frame window inserts to an existing window, you will reduce the noise through the window by up to 80%. Depending on your configuration, the window may not be the weak point and so you'd need to look into how to soundproof a room. If you're unsure on what to do, you can always reach out to us and we'll talk through solutions with you. If your furnace or HVAC unit is in a closet, check out our how-to article for a soundproof hvac closet.  

Often there’s no single right answer to soundproofing. For a problem like a loud air conditioning unit it will depend on your individual situation. Because there’s such a huge variety of potential issues, we’re happy to hop on the phone and discuss your specific situation with you. Give us a call anytime and we’ll help you put together an effective, straight-forward plan that won’t disappoint.