On hot summer days, we all want to have a cold, comfortable room to relax or work in. Having the quietest window air conditioner makes it ideal to sleep, relax, or make conversation with others with ease.
There are several types of air conditioners available in the market. But for many people choosing window-based air conditioners is the most preferred option as it saves space.
There is a growing demand for air conditioners due to more prolonged and hot summer days.
There is a wide range of options when it comes to choosing the best window AC unit. For your comfort, you want something which provides cooling without generating too much noise.
In this window air conditioner review, we listed the top 10 best quietest window air conditioners that will keep you cool all summer long. There is also a handy buyer’s guide later in the article to help you make an informed buying decision.
Top 10 Quietest Window Air Conditioner
Our Top Pick
Frigidaire cool connect window air conditioner is our top pick for the quietest window air conditioners. It has a 10,000 BTU cooling capacity. It’s perfect for providing coverage for a room up to 450 square feet size and comes with a 3-pints per hour dehumidifier.
It has an Energy Efficient Rating of 12, which means it consumes less electricity and saves your utility bill. The built-in smart Wi-Fi allows you to control it with its dedicated app from anywhere in the world or in the room.
The low, under 60 dBA, sound generation makes it ideal for installing it in any room where you don’t want too much noise. The unit comes with an installation kit. You also have the option to get it professionally installed at a nominal fee.
Why should you buy the quietest window air conditioner?
The main benefit is the comfort of being in a room maintained at the right temperature. This means you can work, sleep, and rest in a place without getting annoyed with the constant noise of the air conditioner.
This is more important if you are putting an air conditioner in an office or bedroom. As you may need to concentrate or get some rest without any disturbance.
What to consider when buying Quiet Air Conditioner
The cooling capacity depends on the room size and compressor of AC. For residential use, you can pick 5,000 to 21,000 BTU air conditioners.
The fan speed determines the rate of air circulation. Faster fan speed cools down the room faster but may also be noisier.
You should look for the Energy Star Certification to be assured that the AC is energy efficient. Choose certification above 8 to save on the electricity bill.
Have a question about buying a quiet air conditioner? Contact us
Quiet Window Air Conditioners Review
Here are some of the best quiet window air conditioners available in the market.
1. Haier Serenity Series Window AC
Quiet Small Room Air Conditioner
Haier is a well-known brand with an excellent reputation for producing home appliances. The Serenity series of window air conditioners have an ultra-quiet sound operation. The well-designed compressor blanket on the air conditioner reduces noise. It produces only 44 dBA noise on a low setting.
It has such a low operating sound that you won’t even notice its presence with a sound alone. The durable and high-quality cross-flow fan provides smoother airflow. You can control air direction and speed with its dual-motor design.
It’s rated to be at 6,000 BTU, which is perfect for cooling a room up to 250 sq ft. You can mount it in the bedroom or medium size living room window. The fully functional remote control has a large temperature display and several control options.
It allows you to change the AC’s operation through a press of a button. There are several settings available such as energy saver mode, dehumidify mode, sleep mode, auto cool mode, and a 24-hour on/off timer.
For cleaner air, you have to clean the mesh filter in the air conditioner periodically. This is essential to remove any molds or fungi growing on the screen. You can access the mesh filter through its removable front panel. The mesh is washable, which means you don’t need to buy a new one.
The front digital display electronic control panel shows temperature and time. You can also change the airflow direction in 4 different ways (up-down and left to right).
See More Information about Haier Serenity Series Windows AC
2. Emerson Quiet Kool Window AC
Silent Air Conditioner
Emerson Quiet Kool is an 8,000 BTU window air conditioner that comes with remote control and a smart WIFI system. This model is suitable to cool rooms up to 350 sq ft in size.
You can also choose other models that range from 6,000 to 12,000 BTU based on your needs and the room size. All window air conditioner model comes with built-in WIFI to control it through your smartphone.
If you have a Google Home, you can link with it, and it works through your command to adjust the temperature or to turn it on/off.
At the front of the AC, there is a large temperature display indicator and various options to change the settings. The Eco setting allows the AC to self-regulate the temperature in a very efficient manner.
Although the manufacturer doesn’t mention the decibel rating on the unit, many users reported it to be very quiet under 50 dBA.
If you don’t want to connect your AC with a phone, you have the option to use the remote to control the temperature and fan speed from anywhere in the room.
The AC is intended for window installation and is not designed for standard thru-the-wall installation. So, if you are planning to install it thru-the-wall, then look at other models.
See More Information about Emerson Quiet Kool Window AC
3. LG Quiet Window Air Conditioners
Super Quiet Air Conditioner
Enjoy the perfect cooling in your bedroom or living room without breaking a bank with LG 6,000 BTU quiet window air conditioner. The 6,000 BTU cooling rating means it can comfortably cool room up to 260 sq ft in size. This is enough cooling capacity to cover the average size of living rooms and bedrooms.
The air conditioner generates 53 dBA noise when running at a low speed. For comparison, the sound in the library is 40dBA, whereas the noise inside the car is 60 dBA.
There are several other different models available, and for large rooms, you can pick a 24,500 BTU model. The in-build dehumidifier provides you with extra comfort by adjusting the room humidity level.
There are 3 cooling speed settings plus auto cool mode for your convenience. It comes with a remote but has the basic functionality of controlling temperature, fan speed, and setting up the timer.
It doesn’t have all the bells and whistles that come with other more expensive air conditioner models. But the simple layout of the remote will appeal to several people.
The AC unit comes with an installation kit that you may use to mount it on the window. The anti-corrosion coating provides the protective shield to withstand outdoor elements. This helps the unit last longer.
The energy-saving option lets the system automatically control the temperature without consuming much electricity. However, the unit is not rated with an Energy Star. The washable filter can be quickly taken out of the AC and cleaned.
See More Information about LG Quiet Window Air Conditioners
4. Frigidaire Cool Connect Smart AC
Quietest Window Air Conditioner
Frigidaire cool connect 10,000 BTU AC cools a room up to 450 square feet with 3 pints per hour dehumidification. This smart window air conditioner provides consistent cooling without generating much noise.
You can easily install it in your bedroom for undisturbed sleep or in the living room or office. It allows you to remain undisturbed when you need to have a higher degree of constant focus.
It has a very modern-looking minimalist design that fits perfectly with any interior decoration in the house or office. The large white LED display panel at the front of the air conditioner indicates the temperature. Other control options are at the top of the board with minimal protruding buttons.
The Energy Efficient Rating (EER) of 12 on the unit saves you money on your electricity bills. The built-in wifi connection allows you to control the air conditioner units through your smartphone. Frigidaire provides a dedicated app available for iPhone, iPad, and Android to control the air conditioner.
There are several functionalities in the app, such as turning the unit on or off, changing temperature, controlling cooling modes, and adjusting the fan speed. It has a low noise level of 59dBA at the high setting and 54 dBA at a low setting.
It’s quiet considering the high cooling capacity and ability to cover a larger area. You may not even hear the sound if you are sitting at some distance from the unit.
For maintenance, you get alerts when the filters need to be cleaned. The package comes with an installation kit, and you don’t need anything extra to install it in the window. You can install it on single-hinged or double-hinged windows.
The air conditioner comes with a standalone remote control if you don’t want to use a phone app. The Frigidaire smart window air conditioner is available in 6,000 to 12,000 BTU models but has only a single color to choose from.
If you don’t want to install it yourself, then there is also an option to choose a third-party installer at a nominal price.
See More Information about Frigidaire Cool Connect Smart AC
5. MIDEA Window Air Conditioner
Quietest Room AC
Midea’s 6,000 BTU window air conditioner has 3-in-1 functionality. It has built-in air conditioning, dehumidification, and fan-only mode. It increases the efficiency ratio and saves energy while increasing comfort inside your home or office.
The 6,000 BTU provides cooling from 250 sq ft to 350 sq ft room. The simple non-intrusive design of the air conditioner has a front LED panel to display the temperature and access to other control options. The remote has lots of functionality to control the air conditioner from a distance.
The sleep mode provides maximum comfort as the air conditioner automatically adjusts the temperature throughout the night to align with your body’s natural sleep cycle.
It means you don’t have to wake up to change the temperature in the middle of the night. The 24-hour timer allows you to set the air conditioner to turn on automatically before you get home and shut back off when you leave your home.
The filter is washable, and you get a reminder through a filter LED light located at the front panel. For cleaning, you pull it out from the unit and wash it.
The self-evaporating system recycles condensed water to evaporate. This means you don’t need to drain the condensed water manually or need a water bucket.
The air conditioner is Energy Star rated, which means it’s efficient in using electricity and lowers your utility bills. It produces tranquil 48 dBA noise when running at a slower speed. This is quiet considering its 6,000 BTU air conditioner and covers a more significant size room.
You can install it without significant modification to the existing window frame. It includes all the required accessories and comes with the instruction manual for installation.
See More Information about MIDEA Window Air Conditioner
6. RCA Silent Window Air Conditioner
Quietest 12000 BTU Air Conditioner
The 12,000 BTU wall-mounted window air conditioner from RCA is energy efficient AC that uses a standard 115 V electrical outlet. It can comfortably cool room up to 550 square feet.
The controls are located at the front of the air conditioner. You can adjust the temperature and change the operating mode into either full manual mode or energy-saving mode.
The remote has a flat and straightforward layout. There are no physical plastic buttons but a simple flat design with marking on them.
This looks clean, but it may be hard to operate if you are using it in low-light conditions. It displays temperature in Fahrenheit only, so it may be a bit challenging if you are outside the US and use Celsius.
The AC has a very smooth operation, and it quickly cools down the room in a short time. There is no official dBA rating provided by the manufacturer, but users reported it to be around the 60 dBA range when operating at low speed.
Like other air conditioners, there is convenient access to clean the air filter. It’s a reasonably priced window air conditioner for ample cooling but limited functionality.
See More Information about RCA Silent Window Air Conditioner
7. Koldfront Heat/Cool Air Conditioner
Low Noise Window Air Conditioner
If you live in an area where the summer gets very hot and winter gets very cold, then you should consider this dual functionality heating and cooling air conditioner.
For hot summer days, it provides 12,000 BTU cooling, which is sufficient for 450 sq ft to 550 sq ft room. In cold winter, you can change it to heat mode, and it provides 11,000 BTU/ 3500 W heating functionality.
As a downside, the unit needs a 230 V electrical outlet connection and will not work with a standard 115 V outlet. This means you have to use a voltage converter to make this unit work. If you live in an area where 230 V is standard, then you can plug it directly into the wall.
There is also a cool-only version available if you don’t want to buy both functionalities. You can buy it here. There are 3 fan speed options to control the temperature plus an auto option that self-regulates the fan speed.
The control panel is located at the front from where you can adjust several settings, such as access to energy-saving features, air filter change indicator, sleep mode, and full-auto mode.
The AC comes with a remote control to adjust the temperature setting and control the fan speed. For maintaining comfort, the dehumidifier has 60 pints/day humidifying capacity.
The manufacturer does not provide the decibel rating on the unit, but users reported it to have less than 65 dBA. That’s reasonably quiet, given its significant room size cooling.
See More Information about Koldfront Heat/Cool Air Conditioner
8. Friedrich Chill Series Window AC
Best Window AC Unit
Friedrich, chill series high capacity window air conditioners are sleek, stylish, and energy-efficient. The 18,000 BTU cooling capacity and 12,000 BTU heating power are designed to heat and cool room up to 1,000 square feet.
The design of the air conditioner is sleek and does not look clunky or outdated. The installation is quick and easy with its slide-out chassis. You can install it on the window or thru-the-wall.
You can change the power cord to pass out either the left or right side of the AC, depending on the direction of your power outlet. The auto air sweep feature in the AC moves louvers in different directions to provide consistent air distribution.
You have the option to run the air conditioner in the fan-only mode when cooling. This saves electricity as you won’t be using power-hungry compressors to cool the room if it’s not very hot.
The remote control has full protruding buttons that allow you to use it even at low light. There are different options included in the remote control, such as set temperature, control fan speed, and adjusting the 24-hour timer.
This is a 220 V operating unit, so if you may need to use an adapter if your power supply rating is different. We found Goldsource Step up & Step Down Voltage transformer to provide power up to 2,000 watts Maximum Load Capacity (MLC) that is suitable for most types of Air conditioners.
The air conditioner generates low noise, but there is no manufacturer-provided decibel ratings. However, users reported it to be from 55 dBA to 65 dBA noise output when operating.
See More Information about Friedrich Chill Series Window AC
9. Amana Window-Mounted Air Conditioner
Quietest Bedroom Air Conditioner
Amana 15,000 BTU window-mounted air conditioner comes with 3 cooling speed settings plus auto cooling options. The 15,000 BTU is suitable to cool a room up to 700 Sq ft in size, or if you are planning to use it in the kitchen, that is usually hotter.
You have the option to buy different cooling capacities ranging from 6,000 BTU to 24,000 BTU range. This provides a greater coverage area and cooling flexibility.
It uses 115 V electrical power outlets, so you don’t need any extra adapter to use it. The display is at the front allows you to control the AC and show the temperature.
The dehumidifier in the unit provides 3.5 pt/h dehumidification. You can install AC in the living room or in the office where you need a comfortable temperature and low humidity.
The unit generates 56 dBA to 65 dBA noise when in operation. The installation is easy, and the unit comes with a window mounting kit. It weighs 64 lb and can fit in a 21-inch window. It comes with a fully functional remote control with a large display.
See More Information about Amana Window-Mounted Air Conditioner
10. TOSOT Window Air Conditioner
Best This and That
Tosot 10,000 BTU window air conditioner has a stylish modern design and comes with an Energy Star rating. The 10,000 BTU provides cooling of room up to 450 sq ft size.
If you have a smaller size room, then you also have the option to buy an 8,000 BTU cooling capacity AC that cools a room up to 350 square feet.
It’s essential that you choose the right cooling capacity as buying too low or too high will make you either feel remain hot or spend too much on utility bills for extra unneeded cooling.
This window air conditioner has a very stylish modern design. There are no ugly exhaust grills on the front as those are hidden behind the flat, sleek panel. This allows you to install it in any window of your room without running the aesthetic. The large white LED display tells you the temperature.
It’s good that there is no compromise of functionality over design. The multiple wind direction grill at the top comes with two separate horizontal louvers that allow you to stream fresh air in two different directions. You also have an option to swing it up and down to cover different areas of the room.
It comes with dehumidifiers and fan-only mode. The dehumidifier maintains the right humidity level inside the room for comfort, and the fan-only mode allows you to save on electricity.
The smart control remote has sensors built in the remote to determine the temperature near the user. It then automatically decide how long the AC unit is to operate.
The sleep mode allows the AC to automatically adjust the temperature throughout the night to an optimal sleeping temperature without you manually needing to change it in the middle of the night.
There is no wifi connection, so you can’t operate it through a phone. It’s the remote sensor which manufacturer calls it smart control. The unit runs very quietly and has 69 dBA ratings at high speed and 65 dbA at a lower setting. It produces silent white noise for comfortable sleep.
See More Information about TOSOT Window Air Conditioner
When should you not buy the silent window air conditioner?
When you are looking for an air conditioner, in some cases buying the most silent window air conditioner may not be the best option.
Most air conditioners available in the market are labeled to be the quietest are either small power ratings of 5,000 to 6,000 BTU. This may not be sufficient to cool down a bigger room or simply not have a sturdy fan to circulate the air.
Don’t forget that the primary purpose of buying an air conditioner is to cool down the room. Having an AC that works without producing much noise is the added benefit.
You may think that higher capacity AC marked with low noise generation may be suitable for your needs, but that may not be the case as the fan may be underpowered. This means the air conditioner creates the cooling, but you may have to leave it on for a longer duration.
How many decibels is a quiet air conditioner
The sound level is measured in decibels. This is the pressure the sound waves generate when it travels through the air. The manufacturers of the air conditioner mention the decibel rating to tell you how loud noise the air conditioner unit makes when in operation.
There are three different types of ratings to measure noise, which range from A-weighted, B-weighted, and C-weighted decibels. The noise generated by air conditioners is low-level background noise and measured at the A-weighted noise scale or dBA.
The other B-level decibel and C-level decibel ratings are used to express medium to higher noise levels. One important thing to know about decibel rating is that it doubles the noise level whenever the score increases by 10 units.
For example, noise at 30 dBA will have double the noise level than at 20 dBA even though the increase is only 10 units. Similarly, a 40 dBA will be double the noise level that is generated at 30 dBA.
Keep this in mind when comparing the noise level of air conditioners. For air conditioners, the rating of 40 dBA to 65dBA or less is comfortably quiet. For comparison, the average noise level in the library is around 40 dBA.
The noise level also drops as you go further from the source. This means if you have a larger room, then you can choose a higher capacity but a bit louder air conditioner without getting bothered by the noise. As you may be sitting farther from the air conditioner unit.
Whereas if you have a small room or installing an air conditioner in the bedroom, then you may have to choose a quieter model of window air conditioner for comfort.
Things to consider when buying the quietest window AC
There are so many different types and capacities of the air conditioner model available in the market. It often becomes confusing and mind-boggling to find the right one as per needs.
But as a starting point, you should consider the following:
Cooling Capacity (BTU) and the room size
The cooling capacity of the air conditioner is measured in British Thermal Units (BTU). This simply tells you how good the air conditioner is in transferring heat. This depends on the temperature inside the room and the size of the room.
Most residential air conditioners range from 5,000 BTU to 21,000 BTU. Anything above or beyond that range has a particular use.
The starting point of choosing the air conditioner is to determine the cooling capacity needed based on the room size. Use the following chart to identify the BTU capacity required as per your room size.
Use the above chart as a starting point. There is no reason to buy an underpowered or overpowered air conditioner. As it means more noise and wastage of power.
Besides cooling capacity, you should also look out to lower the humidity level inside the room for greater comfort. Fortunately, most AC comes with dual functionality of cooling and reducing humidity.
Contrary, buying an undersized window air conditioner won’t be able to cool a room faster. You may have to run it at full fan speed, which means more noise and less cooling.
For a room that faces the sunlight, increase the required BTU power by 10%, whereas for the shaded place, decrease the strength of BTU needed by 10%.
For using an air conditioner in the kitchen, add 4,000 BTU on top of regular room size. So, if your kitchen room is 300 sq ft, then you need an 11,000 BTU air conditioner (7,000 BTU capacity for a 300 sq ft room and an additional 4,000 BTU to remove extra heat generated in the kitchen).
The heart of the air conditioner is the compressor that moves the cooling refrigerant through the pipes. It removes the hot air and circulates the colder air to cool the room. The compressor has a motor attached to it that does the heavy lifting in circulating the air.
Air conditioners come in different types and specifications. The silent window air conditioner compressors are inverter types that can be adjusted to operate at variable fan speeds.
It allows greater flexibility and reduces the noise level. You can set the cooling level and the air conditioner automatically adjust the compressor speed based on the cooling requirements.
A well-insulated room prevents the heat from getting inside the room. Most often, the heat transfers inside the room through the circulation of hot air.
If your room is not well insulated and has lots of open spaces, then increase the required BTU by 30%-40%. For a well-insulated or mildly covered room, you can increase the BTU by 10%.
Fan Speeds level
Air conditioners contain a fan that circulates the air to remove the hot air and move in the cold air. Most ACs come with four or five different speed levels. The faster the fan speed, the louder the noise from the air conditioner.
You should pick an air conditioner that has enough capacity to cool the room at the lowest fan speed level. In this way, you will not have to run fans at a higher speed to cool down the place.
The farther the air conditioner is from you, the quieter you will perceive it to be. The noise level decreases as the distance increases.
If you have a bedroom near the window, then you want an air conditioner that can cool down the room at the lowest fan speed level. But if you have a bigger place or your bed is farther from the window, then you can choose the higher capacity air conditioner.
Efficiency And Rating
The air conditioners consume lots of electricity and are not cheaper to operate. A high-efficiency air conditioner cools the room without needing much power.
Many manufacturers use Energy Star certification to assure users of energy efficiency. As a general guideline, the smaller air conditioner units are more energy-efficient than large ones.
The energy efficiency rating goes from a maximum of 12 to a minimum of 8. When choosing an energy-efficient air conditioner, pick units that are rated above 8.
Window air conditioners come with digital or analog temperature controls. We recommend an air conditioner with digital temperature control as it makes it convenient to operate using a remote. It also gives you greater flexibility in choosing the desired temperature level.
Timer and programmable start are nice features to have in air conditioners. It allows you to set the timer once, and then you don’t have to worry about it.
You can program the air conditioner to turn on before you arrive home, so you don’t have to wait for the room to cool down.
Energy-saving and sleep mode
The energy-saving and sleep mode lowers the cooling when not in use, or temperature has reached the desired level. This saves electricity and is environment-friendly.
Since you will be installing an air conditioner inside the window, you have to make sure that it can fit properly. You have to measure the dimensions of your window and then estimate the range of air conditioners that come in that size variety.
Most window air conditioners these days are designed to be used in both single and two-fold hung windows. If you are wall mounting the air conditioner, then think beforehand about which room you will be installing. Make sure there is enough open space to wall mount the air conditioner.
Fan only mode
The fan-only mode option allows you to use the AC without engaging the compressor. This is ideal when the temperature is not too hot, but you need some air circulation inside the room.
The fan-only mode option in AC saves space and money as you don’t have to buy a spare fan.
The remote control is convenient to change the temperature or turn on and off the air conditioner unit without getting out of bed or couch. Depending on the price range of the air conditioner, some remotes may have more functionality than others.
Choose the one which includes the features you will be using most such as temperature settings and fan speed.
How to keep air conditioner quiet
There are some steps you can take to keep the air conditioner remains quiet when operating.
Keep It Away From Sunlight
If it’s possible, install the air conditioner on the side where it does not get exposed to direct sunlight. The sun warms the air conditioner, then it has to work harder to keep the cold air circulating inside the home.
If you have a limited option to install the window air conditioner, then you can install an awning to keep it covered and prevent exposure to direct sunlight.
Close The Curtains
Using dark curtains on the windows prevents the sunlight from getting inside the room. Keep the windows closed during the hot weather as it stops the warm air from getting inside the room.
Clean Air Filter Regularly
The filters in the air conditioner prevent dust or other harmful air particles from getting inside the home. Keeping it clean at least once a week keeps it free from dirt and debris and improves air circulation.
This reduces the required power level needed to cool the room and saves on electricity and reduces the noise level.
Maintain Compressor And Cooling Coil
Proper maintenance of compressor and cooling coil improves the life of the air conditioner. By cleaning any dirt or debris buildup on the compressor will enhance the efficiency of the compressor.
The cleaning of the cooling coil allows the better transfer of cold temperatures to the passing air from the fan.
Tighten Moving Parts
Air conditioners have lots of moving parts. A loose part or screw can create a constant nagging rattling noise that may become uncomfortable and annoying.
By annually checking any loose nuts or screws prevents accidental damage to the unit and also reduces any ratting noise from the air conditioner.
How to reduce electricity consumption when using AC
Several different factors may determine the amount of energy the air conditioner may consume. The first is the overall energy star rating that tells you the energy efficiency of the air conditioner.
Buying a higher energy efficiency rating appliance may help reduce the operating cost of using the air conditioner.
The size of the room is another factor that determines the energy needed to cool the room. The bigger or hotter the area means more energy is required to cool it down.
Using the right cooling capacity of the air conditioner is essential to maintain optimal cooling efficiency and reasonable energy use.
The third way to lower the energy cost of the air conditioner is only to turn it on when needed. There is no reason to keep the air conditioner unit on when no one is inside the room, or you don’t have any other valid reason to keep the room cooler.
You may also consider installing an air conditioner in the room where you spend most of your time.
How can you make the window air conditioner quieter?
Regardless of which type of quietest window air conditioner you purchase, it starts making some noise as it gets old. In older AC units, you may hear various kinds of sounds. By identifying the source of noise, you can fix the problem rather than replace the full unit.
So, if you are wondering why is your window air conditioner making a loud humming noise? Here are some everyday noises you may hear from your AC unit and ways to fix them.
The clanking noise is produced when the compressor does not function properly, or the AC fan blades rub against the metal piece.
You can look closely inside the air conditioner and check if anything is obstructing the fan motion. Also, pay close attention to the compressor to identify the source of the noise.
It will be unlikely that you may be able to troubleshoot the compressor without having any required skills. But sometimes dust and debris on the compressor may cause it to overheat and produce noise. Remove any obstruction and clean the compressor, and then check if the sound still persists.
The clicking noise usually comes from the mechanical thermostat that may have malfunctioned and made a clicking noise.
The mechanical switch in the thermostat moves up and down to make contact with the electric circuit. You should not attempt to fix it while the air conditioner plugged into the electrical outlet.
The humming noise is usually generated when the compressor does not get enough power supply to turn on. This may be a result of a faulty electrical connection or a low power level in the house.
You should not attempt to operate the air conditioner as it may cause permanent damage to the motor inside the compressor. It may become costly to repair.
This happens when either the fan is not balanced correctly or something makes contact with the compressor when in operation.
Most often, you can visually check if there is no obstruction to the fan or any kind of damage or bending to the blades. Get the unit checked by a professional mechanic to prevent any further damage before continuing to use the air conditioner.
The squeaking noise comes when the fan support wheels get dry and may need little lubrication. You can buy motor oil and use a couple of drops at the moving parts to lubricate it.
It usually removes the dirt and debris to keep it moving freely and reduce or eliminate the squeaking noise.