Contemporary air conditioners are designed to stay quiet. These high-efficiency units use 2-stage variable heat compressor technology, as well as sound reduction, in order to keep noise levels under 55 decibels. If you own such a unit, you likely seldom think about its noise levels. That is until the unit begins to sound louder than normal. If this starts occurring, chances are that you will notice, and might wonder if something is going wrong with your unit.

If you begin hearing odd, uncharacteristic noises out of a normally quiet unit, it’s best not to ignore them. The problem could be something that can be addressed by a very basic tune-up, or it could call for major repairs. Sometimes, the repairs would be more costly than replacing the unit altogether. In either case, ignoring unusual noises is not likely to lead to anywhere good in terms of your air conditioner. The longer you let the loud noises continue without addressing them, the higher your risk of costly repairs becomes. To that end, it’s best to address these AC issues without wasting a lot of time.

The sounds you might hear from your air conditioner unit may vary. Here are some common noises that your air conditioner may make and their likely causes.

Air Conditioner Making [Fill in the Blank] Noise

Banging

If you begin to hear banging from inside your unit, it is most likely due to a broken or detached part. It might be a piston pin, a crankshaft, a connecting rod, or any number of other internal components that make up the internal compressor that has snapped or disconnected, or there is a poorly balanced internal blower in play. If a component of a compressor has broken, it is almost certain that the compressor will need to be replaced.

Buzzing

One of the toughest noises to diagnose is when the AC unit begins to buzz. This could be due to a relatively minor and simple repair including changing an air filter to something much more serious. Sometimes buzzing is caused by loose parts inside the unit or the copper lines that run from the outside to the inside of the unit touching something and vibrating off of that surface. It could also mean that there is a debris blockage on the outside or inside of the unit, or the condenser coil requires maintenance or cleaning.

More seriously, it could mean that the internal fan blades are not balanced correctly, the unit has loose parts, the blower is imbalanced or failing, or there is a refrigerant leak. The latter is especially evident if the unit seems to be working but not actually blowing cold air. If the refrigerant has leaked out, it will need to be refilled and the source of the leak needs to be patched.

Clanking

If you hear clanking in your AC unit, chances are there is a part that is not balanced or is loose. This sometimes happens because a particular internal component of the compressor breaks, usually causing the necessity for repair and replacement. If parts are loose, such as the internal fans, it could mean that the out-of-place parts are hitting other internal units. The longer this is permitted to persist, the worse the problems get. Not only will the loose part incur more damage, but it will also likely send the parts it’s hitting into disrepair.

Clicking

When the unit starts up or stops, it is normal to hear clicking sounds, but it is atypical to hear them throughout the unit’s standard operation. If the clicking is frequent or perpetual once the unit is turned on, it could be a sign of a failing thermostat or a defective control. These are typically caused by electrical issues. These can lead to far more costly, and even dangerous problems, so it is important to stay on top of addressing clicking noises if they persist.

Humming

Normal humming is not indicative of a serious issue in AC units. The humming noise could potentially be the result of vibrations due to loose refrigerant piping or other parts, which, if not attended to, can exacerbate into greater problems. Humming is also sometimes due to electrical issues like loose wiring or a malfunctioning compressor.

Pulsating

Another noise that is not always indicative of a problem is when the unit pulsates. In fact, most units have some minor type of pulse emanating from it, which is entirely normal. However, this pulsing should be barely audible unless you are really listening for it. If an outdoor unit begins to make noises that you can hear inside, some parts are likely loose and some part inside the unit needs to be repaired or replaced. These parts can include anything as benign as a panel on the unit coming loose, to loose motor or fan blades, which is a significantly more serious problem.

Rattling

Rattling inside of your unit can sometimes be caused by outdoor debris like leaves and branches being caught in your system, causing a clogging issue. However, it can also be a sign of electrical contractor issues or loosening parts inside the compressor. Loose fans also rattle the more detached and imbalanced they get. If you begin to hear chattering or rattling noises in your unit, your first troubleshooting actions should include checking to make sure that all of the bolts and screws in the unit are tight and snug. You should also consider changing your air filter and cleaning your condenser coil.

Squealing

When indoor blower motors and outdoor fan motors begin to degrade in terms of efficiency, they exhibit the tell-tale sign of squealing as the noises travel through the duct systems. Squealing can also be indicative of malfunctioning or damaged housing or blower wheels. Because certain units may squeal inherently to some degree, it’s important to pay attention to the nature of these squeals in order to distinguish between those that are normal and those that are irregular.

Screaming

The one noise that calls for an immediate ceasing of the use of your AC unit is if you begin to hear a “screaming” or high-pitched whistling noise. At this point, a professional needs to come and inspect the unit and it should not be utilized until the problem is addressed. One of the most common reasons for this problem is a refrigerant leak, which, aside from being highly detrimental to your AC unit, can also harm the health of the residents of your home. Another dangerous reason for the screaming sound is the over-pressurization of the internal compressor. In some situations with this type of problem, the AC unit is equipped with a sensor that will shut the unit off. If this happens, don’t worry. This is a failsafe mechanism included for your safety.

Whirring

A whirring sound, reminiscent of the type of noise expected when a helicopter flies overhead, is an indication of several potential problems with the outdoor unit or the indoor blower. Usually, a whirring sound is indicative of bad bearings around the indoor blower, or a bad fan on either the external or internal AC. While it could also be caused by a torn or ripped belt, the usual cause for whirring noises are displaced or loosened fan blades. The helicopter-like noise occurs when the blades are spinning at an angle, out of place, or hitting what they should not be. But faulty parts are not always to blame. Sometimes, the whirring noise can be due to a piece of debris being stuck in the outdoor fan or the indoor blower. As it gets caught up in the blades, it simulates a helicopter sound as well.

What To Do About a Loud Air Conditioner

What To Do About a Loud Air Conditioner

You do not always need to worry about calling a professional for AC unit repairs. When there is a new noise that you are not accustomed to hearing, you should investigate the unit yourself as many problems have DIY solutions. A lot of the time the solution is quite simple. Various debris, including tree branches, twigs, leaves, and seed pods are well known to clog up conditioning coils, resulting in buzzing or pulsing sounds.

You can remove the top of your air conditioning unit with just a screwdriver in most cases, and closely inspect the fans. Loose parts, especially when in motion are usually easy to spot. You can also change the filter on your unit, as well as clean an outdoor one from all the nature dumps on it with a spray from a hose.

If the noises begin to be concerning, before inspecting a unit with the cover off, it is always advisable to power it down. You should do this regardless of whether a professional is coming over to take a look at it or you are checking it out yourself. This is a very basic precautionary measure. If the air conditioner unit is broken, keeping it running could only expedite the damage and prove to be more costly than if you had just stopped it after the initial problem was noted. To stay on top of potential looming issues, it is always a good idea to schedule an annual tune-up where professionals will check the status of all of the important parts involved and hopefully give your AC a clean bill of health.

Make Air Conditioner Quieter

Make Air Conditioner Quieter

If there is nothing wrong with your unit, but you still feel that it is far too loud, there are a couple of options to make it quieter. A sound blanket is one option. Since most of the noise from an AC unit is sourced from its compressor, a sound blanket can be installed over it in order to muffle the compressor’s sounds.

A sound-dampening fence around the unit is another common option for homeowners. Not only does it obstruct the often unaesthetic unit from sight, but it also helps to quiet the noise from the unit as it is obstructed by the fence. This type of fence is best installed by using fencing with overlapping boards, though it’s important to permit a space of at least three feet between the fence and the unit to allow the AC the ability to exercise proper airflow.

Another method that homeowners enjoy for sound-dampening their AC units is to plant shrubs around the air conditioner. Of course, these will need to be at a bit of distance and will need to consistently be pruned back in order to not grow into or obstruct the optimal operation of the unit.

Additionally, many homeowners also place plants against the windows inside the home, specifically those that are near the AC unit. Larger houseplants against the AC adjacent wall typically help to block the noise more. On top of that, if the AC unit is outside of a bedroom, it’s a good idea to install noise-smothering curtains in order to keep the noise level down for sensitive sleepers.

When Is It Time To Replace A Noisy Air Conditioner?

When Is It Time To Replace A Noisy Air Conditioner

Older units that begin to be noisy are usually best if they are discarded and replaced. While repairs are still possible, some problems are just too expensive to address. For instance, older units used R22 refrigerant, which has since been replaced by R410-A in newer units. However, the two are not interchangeable, so older units require their type of refrigerant. The problem is since it’s far less common these days, it gets more challenging to find services that still stock and carry R22, and its acquisition ends up being more costly.

As the main functional component of an air conditioning unit, when the compressor becomes deficient it will likely cost more to replace it than to just invest in a new unit. The newer unit will carry the benefits of being quieter, as well as more energy efficient. You might find that your electric bill drops substantially with a new unit, meaning that over its life, the savings will have the unit pay for itself.

If your air conditioner needs replacement, look into a company that can provide a strong warranty. This could save you substantial money on costs or the unit and its installation. This will also help you rest assured that you are operating a newer, quieter, and more reliable AC unit.