Window air conditioners should generate as little noise as possible. These AC units are a bit elevated and in tight contact with a rigid window sill, allowing for vibrations; any noise a window AC makes will propagate throughout the room.
Wall-mounted air conditioners are not the loudest type of air conditioners; they are, however, also not the quietest. If you pick the wrong model, you’re easily looking at a 70+ dB window AC unit that’s anything but calm and silent.
It makes a lot of sense to choose the quietest window air conditioner in a smart way. At first, choosing a super quiet AC unit seems easy enough:
Just look at 100 window AC units, check their decibel levels (it’s usually an interval; Example: 54-62 dB) on the specification sheet, and pick the unit that has the lowest noise levels.
This is exactly what we did to come up with the list of the quietest window air conditioners in 2021.
Low noise levels are not everything.
Example: A silent window air conditioner generates only 52 dB in the highest fan speed setting. But it has an EER rating of 9.0, subpar BTU capacity, and comes from a brand known for malfunctions. We can all agree that this is not the best quiet window air conditioner, despite the very low noise levels.
Picking such an ultra-quiet window AC unit will result in:
- Unnecessarily high electricity bills (low EER rating).
- Insufficient cooling effect (subpar BTU capacity).
- Shorter window AC lifespan (known malfunctions).
In short, the quietest window air conditioner should not only have a whisper-silent operation; it should also be one of the best window AC units according to other important specifications.
Based on these two concepts, LearnMetrics has compiled a list of the 9 quietest window air conditioners in 2021. You can check it further below or, if you’re in a hurry, skip to it here:
First things first, however. To properly understand and make an informed decision regarding the ultra-quiet air conditioners, we will have a look at the parts of window air conditioner create noise.
We shall also look at other secondary specifications apart from noise levels (measured in decibels) you need to check before buying a quiet window air conditioner. These include EER rating, cooling capacity (BTU), coverage, airflow, and dehumidification rate.
Let’s start with the most important question regarding the window air conditioners and decibels:
What Makes Window Air Conditioners Silent? (Or Loud)
Whenever trying to minimize the noise levels of any device, we need to check the parts that are making the most noise.
In the case of window air conditioner, there are 3 noise generators:
- Compressor. Usually the noisiest part. Rotary compressors are especially loud because they ‘kick in’ with a loud thrumb. Quiet window AC units use inverter compressors.
- Airflow. High airflow equals higher noise levels. That’s the reason why bigger (12,000+ BTU) window AC units are louder.
- Any vibrations. Window AC units are mounted to a hard window sill; any unbalance in the unit can create vibrations. AC housing repeatedly hitting the window sill will surely generate a lot of noise.
Engineering Rules To Create A Quiet Window AC Unit
To create a quiet window air conditioner, engineers simply have to acknowledge these sound sources and minimize each of these 3 noise generators. Here’s how:
- Installing an inverter compressor. Window air conditioners with inverter compressors are quieter (3-6 dB difference) compared to rotary compressors.
- Creating a low airflow – high cooling effect window AC unit. That means the temperature of output air is lower; thus the airflow to achieve the same cooling effect (measured in BTU) can be lower.
- Well-balanced window AC will prevent vibrations. Symmetrically designed units are preferred.
2 DIY Measures That Additionally Lower Noise Levels
All the best quiet window air conditioners you’ll find in the list follow these rules. On top of these, you yourself can do two things to minimize the noise levels of window air conditioners:
- Choose a bigger capacity window AC and run it at a lower speed. Example: To cool 350 sq ft room, you would need an 8,000 BTU with 52-56 dB noise levels. It will generate 56 dB because you’ll have to run it at high speed. If you choose a 10,000 BTU quiet window AC unit with 54-58 dB noise levels, you will cool the same room running this unit at low speed; generating 54 dB.
- Use insulation foam to muffle the noise vibrations could potentially cause. Simple enough a measure anybody can follow. Contrary to what some people might think, using foam does not reduce the total effective noise levels of the compressor significantly.
Some sources might also recommend some secondary maintenance measures to keep a silent operation of the window AC unit. These include cleaning filters, coils, and compressor on an annual or biannual basis.
While proper maintenance is essential to ensure the longevity of the window air conditioner, cleaning all the nooks and crannies does not significantly reduce noise levels.
Specs To Look For In Addition To Window AC Unit Decibel Levels
As we have discussed, the quietest air conditioner shouldn’t only be whisper quiet. It should also be:
- Energy-efficient. Why unnecessarily waste power and money, if there are plenty of 10+ EER window air conditioners with silent operation.
- Powerful enough. Buying a too small quiet window AC will reduce the lifespan of the unit and you’ll have to run it on 100% all the time (maximum noise levels).
- Reliable. Little to no known malfunctions of that particular low-sound window AC unit is perfect; brands like TOSOT, Haier, and Frigidaire make the most reliable units.
Energy-Efficiency Of Quiet Window AC Units
The energy efficiency of window AC units is expressed as EER rating (Energy-Efficiency Ratio). A high EER rating will save you electricity and money (up to $100 per season). Here’s are quick benchmark figures about energy-efficiency of quiet window AC units:
- EER rating below 8: Energy inefficient.
- EER rating between 8 and 10: Standard energy-efficiency.
- EER rating 10 or above: Superb energy-efficiency.
If you check the list of the super quiet window AC units below, you’ll see that all of them are high-efficient units with EER rating up to 12.1.
For Silent Operation, Choose A Bigger Window AC
The cooling capacity of window AC units are expressed in BTU (British Thermal Units). Quiet window ACs range from 5,000 BTU to big 18,000 BTU units.
How to properly size a window air conditioner for the quietest operation?
Here is what EPA recommends:
“Air conditioner generally needs 20 BTU for each square foot of living space.”
In order to ensure a silent operation (give you the ability to run a window air conditioner at lower noise speeds), you should use 25 BTU or even 30 BTU (to be safe) per square foot.
Here are rough estimates of how big a window AC you need to achieve a silent operation in certain room sizes:
|Room Size||Capacity Of Window AC (For Silent Operation)|
|200 sq ft||6,000 BTU|
|300 sq ft||9,000 BTU|
|400 sq ft||12,000 BTU|
|500 sq ft||15,000 BTU|
|600 sq ft||18,000 BTU|
Are Quiet Window Air Conditioners Reliable?
Window air conditioners, on average, last for 10 to 20 years. Quieter window AC units usually last longer than standard noise-level units. The reduction in vibrations and the use of inverter compressors prolong the lifespan of quiet window AC units.
The reliability of any specific unit is very well correlated with the brand. Well-known brands like TOSOT, LG, Frigidaire, and Haier have but their reputation for producing reliable window air conditioners. Choosing a recognizable brand is the safest bet.
Obviously, to ensure your quiet window air conditioner will last for closer to 20 years is regular maintenance. Maintenance of quiet window air conditioners is the same as for the louder units; just be sure to clean the filters, coils, and compressor once per year.
Best Quiet Window AC Units Currently On The Market
Here are the best silent window air conditioners in no particular order. The higher 10,000+ BTU units are usually a better choice because you can run them on a low-noise lower speed and still generate more cooling effect than the smaller 5,000-8,000 BTU unit:
- TOSOT Tranquillity: Quietest Window Air Conditioner Overall.
- Soleus Air Exclusive: Quietest 6,000 Window AC Unit.
- Haier Serenity: Whisper Quiet Haier Window AC Unit.
- Keystone KSTAW05BE: Small Quiet 5,000 BTU Window Air Conditioner.
- TaoTronics TT-AC001: Quiet 10,000 BTU Window AC Unit.
- Frigidaire FFRE123WAE: Best Quiet 12,000 BTU Frigidaire Window AC Unit.
- Emerson Quiet Kool EARC15RE1: Quietest 15,000 BTU Window AC Unit.
- Frigidaire FFRE1833U2: Biggest Quiet 18,000 BTU Window Air Conditioner.
- LG LW8017ERSM: Quietest LG Window Air Conditioner.
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1. TOSOT Tranquillity 8,000 BTU (Quietest Window Air Conditioner Overall)
|Max. Noise Levels:||42-49 dB|
|Cooling Capacity:||8,000 BTU|
|Coverage:||Up to 350 sq ft|
|Dimensions (LxWxH):||21.4 x 18.8 x 14|
TOSOT Tranquillity is a window AC unit that was specifically designed for quiet operation – hence the name ‘Tranquillity’. Every aspect of the unit is engineered to make as little noise as possible. Overall, this is the absolute quietest window air conditioner currently on the market.
Tranquillity has a variable airflow output, with max. the airflow of 212 CFM. To top operating noise level is 49 dB. However, if you put it in a room that is a bit smaller than the recommended 350 sq ft, the noise levels can drop as low as 42 dB. This is a whisper-quiet 8,000 BTU window air conditioner.
On top of being the quietest unit, TOSOT has taken care of secondary specifications that are of utmost importance in the long-term. The very high 12.0 EER rating indicates just how energy efficient TOSOT Tranquillity is. Running a 12.0 EER 8,000 BTU window air conditioner, for example, will cost less than $100 per year (as low as $65).
For installation purposes, the width of quiet window air conditioners is important. TOSOT Tranquillity is 21.4 inches wide; do account for that when measuring the space on the window. Of course, the installation kit should include insulation on each side of the unit.
In short, TOSOT Tranquillity is the quietest window air conditioner with as low as 42 dB noise levels. TOSOT is known to produce highly energy-efficient and reliable units, and they have specifically designed TOSOT Tranquillity as the ultra quiet 8,000 BTU window air conditioner:
2. Soleus Air Exclusive (Quietest 6,000 Window AC Unit)
|Max. Noise Levels:||38-49 dB|
|Cooling Capacity:||6,000 BTU|
|Coverage:||Up to 275 sq ft|
|Dimensions (LxWxH):||21.25 x 23.25 x 15|
Let’s first cover the Soleus Air Exclusive’s noise levels before we check the superb “saddle” design. Soleus Air Exclusive has an amazingly low noise level interval. In fact, this is the quietest 6,000 BTU window air conditioner.
At the lowest speed setting with 170 CFM airflow, the Soleus Air Exclusive generates less than 40 dB of noise. 38 dB to be exact. With increasing noise levels, of course, the noise levels are increased but even at the highest fan speed that generates 270 CFM airflow, the noise levels are still ridiculously lower – 49 dB is the max. noise level.
Soleus Air Exclusive is a testament to how a little bigger air conditioner can cool a smaller room quietly. At top speed, it will generate 6,000 BTU of cooling power, enough to cover rooms up to 275 sq ft (at 49 dB). However, if you put it in a 150-200 sq ft room, you can run it at a low-speed setting. Effectively, you will generate about 4,000 BTU at only 38 dB noise level; that’s quieter than a library.
Apart from being an incredibly silent window air conditioner, the design of Soleus Air Exclusive is essential. The “saddle” design means that the AC unit doesn’t sit on top of the window sill, steering the view. Rather, it is saddled on the window sill, giving you a view almost as clear as without the AC. Here’s how it looks on the window sill:
Soleus Air Exclusive is also one of the most energy-efficient quiet window air conditioners. It has a superb 12.1 EER rating, with an optional energy-saving mode.
What is more, 8,000 BTU Soleus Air Exclusive is also available and has a similarly low noise levels interval.
All in all, the Soleus Air Exclusive is one of the best quietest 6,000 BTU window-mounted air conditioners with the space-saving “saddle” design:
3. Haier Serenity 6,000 BTU (Whisper Quiet Haier Window AC Unit)
|Max. Noise Levels:||42-52 dB|
|Cooling Capacity:||6,000 BTU|
|Coverage:||Up to 275 sq ft|
|Dimensions (LxWxH):||21.25 x 18.13 x 12.44|
Haier is one of the best-known producers of HVAC designers. Fortunately, they invested in engineering a quiet 6,000 BTU window air conditioner; the Haier Serenity model. “Serenity” is, like TOSOT “Tranquillity”, a marketing term to communicate how quiet their window AC unit is. Let’s look at the noise levels:
Haier Serenity has a wide 42 dB to 52 dB noise level interval. As such, it is below the 60 dB throughout the interval and is truly considered a super quiet 6,000 BTU window air conditioner. It generates up to 200 CFM airflow; a low airflow generates less noise which is exactly the point.
What is more, all Haier AC units tend to have above-average energy-efficiency. Haier Serenity has an extremely high 12.1 EER rating; it’s as energy-efficient as it is quiet.
It’s designed to silently cool smaller rooms up to 275 sq ft. Realistically, it is recommended to be used in rooms up to 200 sq ft for a low-noise operation. At 100% full capacity, it will produce 52 dB of noise, but if you run it on 80% the noise levels can drastically decrease to 42 dB.
As such, this is the quietest Haier window air conditioner. It’s easy to install on a window sill of a smaller room and, given this is Haier, it’s very reliable:
4. Keystone KSTAW05BE (Smallest Quiet 5,000 BTU Window Air Conditioner)
|Max. Noise Levels:||49-55 dB|
|Cooling Capacity:||5,000 BTU|
|Coverage:||Up to 275 sq ft|
|Dimensions (LxWxH):||15.4 x 16 x 12|
Keystone KSTAW05BE is the smallest quiet window air conditioner. There are not that many 5,000 BTU window AC units. Among those, the Keystone KSTAW05BE is the quietest. However, despite being smaller, it’s not exactly as whisper quiet as bigger units.
For example, Keystone KSTAW05BE produces 55 dB of noise (still extremely low for a window AC) at 129 CFM. At lower speed (100 CFM), the lowest noise level is 49 dB.
For a 5,000 BTU unit, it also has a very good energy-efficiency. Keystone KSTAW05BE’s EER rating is 11.2.
Keystone KSTAW05BE is the quietest 5,000 BTU window AC unit that can be engineered. With bigger units, engineers have more options of how to reduce noise levels. Keystone KSTAW05BE’s weight is only 40 lbs; it’s quite a challenge to cram all the noise-canceling insulation and the inverter compressor in such a small unit.
Nonetheless, Keystone KSTAW05BE is, despite not being the quietest among the quiet window air conditioners, reasonably silent. In fact, it’s the most silent 5,000 BTU window AC unit and available at a heavily reduced cost compared to other quieter units:
5. TaoTronics TT-AC001 (Super Quiet 10,000 BTU Window AC Unit)
|Max. Noise Levels:||38-? dB|
|Cooling Capacity:||10,000 BTU|
|Coverage:||Up to 460 sq ft|
|Dimensions (LxWxH):||21.3 x 15.7 x 21.5|
TaoTronics TT-AC001 is considered one of the quietest 10,000 BTU window air conditioners. At the low-speed setting, it generates only 38 dB of noise. What is more, it’s very energy efficient with a 12.0 EER rating.
The TT-AC001 will fit 24″ to 40″ windows. It has an above-average number of features, such as 3-speed settings, ECO mode, Auto mode, and even a 24-hour timer.
The key to quiet performance is the use of two independent motors. Combined, they manage to generate as much as 10,000 BTU of cooling effect at a very low noise level. Exactly how quiet the TaoTronics TT-AC001 is at the highest speed setting?
We simply don’t know. The specification sheet doesn’t include the max. noise levels and that may be a cause of concern. However, according to anecdotal experience, TaoTronics TT-AC001 is one of the super quiet window air conditioners. The use of dual motors seems to be working out.
All things considered, the TaoTronics TT-AC001 is the quietest 10,000 BTU air conditioner at low speed. It generates as little as 38 dB, has a 12.0 EER rating and is available at an affordable price:
6. Frigidaire FFRE123WAE (Best Quiet 12,000 BTU Frigidaire Window AC Unit)
|Max. Noise Levels:||57-59 dB|
|Cooling Capacity:||12,000 BTU|
|Coverage:||Up to 550 sq ft|
|Dimensions (LxWxH):||21.5 x 19 x 14.5|
Frigidaire is probably the company with the best engineering department. In their window AC portfolio, they include the super quiet 12,000 BTU Frigidaire FFRE123WAE window air conditioner that lives up to the Frigidaire name.
The Frigidaire FFRE123WAE has a very narrow interval of operation as far as the noise levels are concerned. At the low-speed setting, this quiet 12,000 BTU window air conditioner generates 244 CFM of airflow and 57 dB of noise. At the highest setting, the airflow is increased to 300 CFM and noise levels to 59 dB.
As such, this is a very quiet window air conditioner; albeit it’s not the quietest of them all. Obviously, 12,000 BTU is quite a lot of cooling power, and Frigidaire FFRE123WAE needs a higher – 300 CFM airflow – to achieve it.
The energy-efficiency is very high. The 12.0 EER rating is one of the highest in the industry; this is an electricity-saving device and has even earned the Energy Star rating for eco-friendliness.
The best part of Frigidaire is the reliability. All of their window AC units are extremely durable; built to last. It’s not unusual for a Frigidaire AC unit to last 20 years.
Frigidaire FFRE123WAE is one of the quietest 500 sq ft window air conditioner. With 12,000 BTU, it can cool down spaces up to 550 sq ft but it has a quieter operation if you run it on 90% capacity in 500 sq ft room. On top of all that, the Frigidaire is the essence of reliability:
7. Emerson Quiet Kool EARC15RE1 (Quietest 15,000 BTU Window AC Unit)
|Max. Noise Levels:||52-56 dB|
|Cooling Capacity:||15,000 BTU|
|Coverage:||Up to 700 sq ft|
|Dimensions (LxWxH):||23.6 x 35.4 x 17.9|
Emerson Quiet Kool is a brand that specialized in engineering quiet air conditioners. Their quietest window AC unit is the Emerson Quiet Kool EARC15RE1 with 15,000 BTU of cooling effect. This is the biggest quiet window air conditioner that still uses 115V.
Given Emerson Quiet Kool is built with low-noise in mind, they have managed to produce a 15,000 BTU that generates only 52-56 noise levels. In comparison, even the #6 Frigidaire 12,000 BTU unit generates a few decibels of noise more.
With standard 115V voltage, the highest possible capacity is 15,000 BTU. EARC15RE1 is designed to be the biggest silent window AC unit that can be powered by the standard wattage.
Bigger units can use quite a lot of electricity if they have subpar energy-efficiency. Emerson Quiet Kool EARC15RE1 has a high 11.9 EER rating and it is, as such, also the most energy-efficient big 115V window AC that still manages to keep the noise levels under 60 dB.
The minimal window length is 28 inches; if you have a narrower window, you won’t be able to install such a big device. Do measure the window length before buying the unit.
15,000 BTU is enough to cool down spaces up to 700 sq ft, true. However, for silent cooling, it’s best if you run the Emerson Quiet Kool EARC15RE1 at 70-80% capacity which is enough to adequately lower the temperature in spaces up to 500-600 sq ft.
All in all, it’s not a wonder that Emerson Quiet Kool EARC15RE1 is the quietest 15,000 BTU window air conditioner. They are known exactly for their quiet cooling devices and the EARC15RE1 is their big crowning jewel:
8. Frigidaire FFRE1833U2 (Biggest Quiet 18,000 BTU Window Air Conditioner)
|Max. Noise Levels:||55-59 dB|
|Cooling Capacity:||18,000 BTU|
|Coverage:||Up to 1,020 sq ft|
|Dimensions (LxWxH):||27.4 x 23.6 x 17.7|
Frigidaire FFRE1833U2 is the quiet powerhouse window AC unit. The specs are incredible: it is the only quiet 1000 sq ft window air conditioner, it weighs 126 lbs, and it has the incredible 5.5 Pint/h dehumidification rate. On top of that, the fan can generate up to 430 CFM airflow.
All these superb metrics usually have a downside, at least as far as the noise levels are concerned. It’s almost impossible to engineer an 18,000 BTU window air unit with below 60 dB noise levels. Frigidaire is one of the few companies that managed to decrease the noise levels of the FFRE1833U2 to as low as 55 dB.
At the highest output – 430 CFM, 18,000 BTU – the Frigidaire FFRE1833U2 generates only 59 dB noise levels. That’s absurdly silent for such a beast of a window air conditioner.
EER rating is even more important in the case of high capacity AC units. Frigidaire FFRE1833U2 has managed to drop the wattage so much that it achieved the 11.9 EER rating. For that, the model was awarded an Energy Star certificate.
The only real drawback is the unavoidable 230V voltage that is needed to power all 15,000+ BTU window air conditioners.
The true advantage of Frigidaire FFRE1833U2 is that it can cover spaces up to 1,020 sq ft. That means that it can cool down several rooms at once. The noise coming from the window air conditioner is the loudest in the room where the AC unit is installed. In other rooms that are cooled by the unit, the noise levels are still lower.
When buying bigger units, reliability is essential. Frigidaire is known as the most reliable window AC producer and the Frigidaire FFRE1833U2 model is no exception. This is the biggest and the quietest 18,000 BTU window air conditioner, available at an affordable price:
9. LG LW8017ERSM (Quietest LG Window Air Conditioner)
|Max. Noise Levels:||42-49 dB|
|Cooling Capacity:||8,000 BTU|
|Coverage:||Up to 350 sq ft|
|Dimensions (LxWxH):||19.4 x 19.6 x 12.4|
LG is one of the best-known producers of window AC units with the broadest portfolio. LG LW8017ERSM model is their the quietest LG window air conditioner with 8,000 BTU; similar variations are also available with 5,000 BTU, 6,000 BTU, 10,000 BTU, 12,000 BTU, and 18,000 BTU (230V) cooling power. All of these units have a similar noise levels interval (bigger ones have a bit higher noise levels, obviously).
LG LW8017ERSM is a great example of a quiet 8,000 BTU LG window air conditioner. It can produce up to 220 CFM airflow and generates anywhere from 54 dB to 60 dB noise levels. If you think this is not the quietest air conditioner currently on the market, you’re correct; however, LG does create one of the best overall AC units.
For example, LG LW8017ERSM has a high energy-efficiency EER rating of 12.0. Compared to other quieter window ACs, the LG units are cheaper by quite a lot. If you need a reliable and budget-friendly AC unit, LG is always the way to go, despite a bit higher noise levels.
Having a variety of cooling capacities – from 5,000 BTU to 18,000 BTU – is also an advantage. It gives you a whole range of quiet window air conditioners to choose from:
If you have any questions about the low-noise window AC units, you can pose them in the comments below. If you find an even quieter window AC, you are most welcome to bring it to our attention, and we’ll review it based on the same standards as all other devices.