To cool a small room, you need a very small window air conditioner. We are going to check which are the smallest air conditioner window units on the market, based on a spec-by-spec and dimension-by-dimension analysis. You can find a full 5 smallest window air conditioner comparison chart, complete with reviews, further on.
Now, the whole point of getting a very small window air conditioner is to avoid needless and expensive overkill units. What does it mean that a window AC unit is small? Well, here are a few options:
- Minimum dimensions (most compact window AC). This means that a window AC unit has the smallest width, height, and depth. We have calculated the volume of the smallest window AC units to actually see which ones are the most compact. We are talking about 15 or 16-inch wide window AC units, with below 16-inch height, for example.
- Minimum cooling output (BTUs). Another way to think about the smallest window AC is to check which one has the lowest BTU output. Window AC units range from the smallest 5,000 BTU units to the biggest 25,000 BTU units. We are going to focus on those with 5,000 BTU since these are the most compact, as well as two 10,000 BTU units because they are either amazing (#4 Midea) or very narrow (#5 PerfectAire).
- Most powerful small units. We have calculated the BTUs per cubic inch (volume) to see which window AC units have the smallest volume while having the biggest cooling effect. The most effective window AC unit, #4 Midea U-Shaped MAW10V1QWT, has an outstanding 1,80 BTU per cubic inch output.
- Narrowest window AC unit. Most small AC units will fit standard windows (window width from 22 to 36 inches, and window height of 13 inches or more). If you have a very narrow window, you should go with the narrowest window AC unit (that’s the #5 PerfectAire 3PASC10000 that can fit windows with widths as small as 15.5 inches).
That’s the “small” part. Getting the smallest size window air conditioner is only half of the equation. The other half is that this unit should also be energy efficient (CEER, EER ratings), lightweight, have low noise levels, reliable, made by a reputable HVAC manufacturer, and preferably be cheaper than $400. So, no pressure getting a small window AC unit that excels at all these specs.
If you are buying a window AC unit for the 1st time, you should go through the factor-by-factor introduction guide we are going to start with. If you already have an idea what to look for when comparing extra small window AC units, you can just jump to the list of the 5 smallest window AC units here:
Alright, to get a good grip on what to check when selecting the perfect small window AC unit, we are going to go through all the factors. We are going to start with the BTUs and room coverage, proceed with energy efficiency ratings, look at the dimensions, total volume, and compactness (BTU per cubic inch), window width and height requirements, noise levels, max. airflow (CFM), and look at the benchmark prices for small window AC units.
Let’s start with the BTUs and coverage:
1. How Many BTU Do Small Window AC Units Have, What Size Rooms They Can Cover?
Needless to say, very small window air conditioners will cool small rooms. How small exactly? Well, in HVAC, we generally use a 20 BTU per square foot. This is, however, a rule of thumb that works superb for big AC units but gets a bit inaccurate when sizing small window AC units.
To figure out the room coverage of small window units, it’s best to use this sizing chart by Energy Star:
|Window AC Capacity (BTU):||Room Size:||Room Dimensions (Examples):|
|5,000 BTU||Up To 150 Sq Ft||8×8, 10×10, 10×12, 12×12 Rooms|
|6,000 BTU||150 To 250 Sq Ft||12×14, 14×14, 14×16 Rooms|
|7,000 BTU||250 To 300 Sq Ft||16×16, 16×18, 14×18 Rooms|
|8,000 BTU||300 To 350 Sq Ft||18×18, Two 12×12 Rooms|
|9,000 BTU||350 To 400 Sq Ft||18×20, 20×20, Two 14×14 Rooms|
|10,000 BTU||400 To 450 Sq Ft||Three 10×10 Or 12×12 Rooms, 22×22 Rooms|
In the chart below, you will notice that the first 3 smallest window AC units (#1, #2, and #3) have a 5,000 BTU cooling capacity. That means they are adequately sized for very small rooms like 8×8, 10×10, 10×12, and 12×12 rooms.
The last 2 units (#4 and #5) have a 10,000 BTU cooling capacity. The #4 Midea U-Shaped MAW10V1QWT is the most compact unit (1,80 BTU per cubic inch), and #5 PerfectAire 3PASC10000 is the narrowest window air conditioner (you can have a window width as small as 15.5 inches).
Adequately sizing a small window AC unit is very important. If you pick a too big one, you are effectively adding needless expenses, and if you pick one that is too small, you will probably still have a room that’s too hot.
With 10,000 BTU units, you also have to be aware about the airflow (expressed in CFMs). Namely, these units can cool 1 bigger room (up to 22×22) or 2 or even 3 smaller rooms (10×10 or 12×12 rooms). For the small window AC unit to be able to distribute the cooling output evenly, you need to have an above 200 CFM airflow.
Airflow propels the created cold air through the 2nd and 3rd room. If you check the spec-by-spec comparison chart, you can see that Midea window AC unit has 258 CFM and the narrow PerferctAire unit has a 323 CFM; this is sufficient airflow to cool several 12×12 rooms evenly, for example (no hot spots).
Before we check what are the dimensions of the smallest window air conditioners, let’s focus on energy efficiency:
2. Small Window AC Energy Efficiency Ratings (CEER, EER)
For big AC units, energy efficiency is vital. This translates to lower running costs (energy savings). With the smallest window AC units, energy efficiency is important but, admirably, not to the same degree as with big AC units since these small units don’t use all that much electricity.
For window AC units, we have a new CEER rating that denotes energy efficiency. CEER stands for Combined Energy Efficiency Ratio Rating. The higher the ratio, the more efficient small window air conditioner you have.
An average window AC unit will have a CEER rating within the 8 to 10 CEER range. Here is a rough estimation what CEER ratings window AC units with different efficiencies have:
- CEER below 6: Very inefficient unit.
- CEER between 6 and 8: Below average efficiency.
- CEER between 8 and 10: Average efficiency of a small window air conditioner.
- CEER between 10 and 12: Above average efficiency.
- CEER above 12: Very high efficiency.
If you check the list of small window AC units below, you can see that the first 3 have 11 CEER. This is an above-average efficiency. The #5 narrow PerfectAire unit uses the old EER rating (10.4 EER).
The #4 Midea U-Shaped MAW10V1QWT excels when it comes to efficiency. With the outstanding 15 CEER rating, it is the most energy-efficient window AC unit not only among small and compact unit; it is one of the most energy-efficient window AC units in general. Here is the energy efficiency analysis by Energy Star.
In short, it is good to have an energy-efficient small window AC unit. However, we should keep in mind that energy efficiency is a primary factor with bigger HVAC units; in the case of looking for just a very small window AC unit, it is a secondary factor.
Let’s have a look at the dimensions of the tiny window AC units:
3. Dimensions, Volume, And Compactness
Obviously, if we want to know which window AC unit is the smallest, we have to check the dimensions. Here are rough estimates on how wide and how high window AC units are, along with the depth dimensions:
- Width of window ACs ranges from 14.5 inches to over 30 inches. The narrowest units will have below 15-inch width. Standard-form small window AC units have about 16-inch width.
- Height of window ACs ranges from as little as 12 inches to over 25 inches. In the chart below, you can see that 5,000 BTU units have below 16-inch height. The special case here is the #4 Midea U-Shaped MAW10V1QWT that has below 14-inch width (super small for 10,000 BTU unit) and sits on the window sill, thereby reducing the height over the window sill even further.
- Depth of window ACs ranges from 12 inches to over 30 inches. This dimension is usually less relevant.
From all these dimensions, we can calculate the total volume. The smallest window air conditioner has the smallest total volume; that’s the #1 Frigidaire FFRA051WAE unit with only 2,929 cubic inches volume (less than 1,70 cubic feet).
Very small 5,000 BTU window AC units will have around 3,000 cubic inches of volume. Bigger 10,000 BTU units will have up to 8,000 cubic inches of volume; as you can see in the chart below, both #4 and #5 units have a below 8,000 cubic inches volume.
Now, small 5,000 BTU window AC units are smaller than 10,000 BTU units, right? However, when we calculate the compactness factor, we have to take into account the total volume of a window air conditioner as well as the BTU output.
We can calculate the compactness or cooling output per cubic inch like this:
Window AC Compactness = BTU Output / Total Volume (In Cubic Inches)
The most compact window AC units will be as small as possible and produce as much cooling output as possible. Usually, you will see that most small window AC units produce less than 1,50 BTU per cubic inch of volume. The chart below shows that all but the #5 unit have an above 1,50 BTU per cubic inch compactness.
Here are the top 3 most compact window air conditioners:
- #4 Midea U-Shaped MAW10V1QWT has a 1,80 BTU per cubic inch compactness. This is a 10,000 BTU unit.
- #1 Frigidaire FFRA051WAE has a 1,71 BTU per cubic inch compactness. This is a 5,000 BTU unit.
- #2 hOmeLabs HME020003N has a 1,69 BTU per cubic inch compactness. This is a 5,000 BTU unit, comparable to #1 Frigidaire FFRA051WAE.
These are the dimensions of the window AC units themselves. What about the dimensions of a window that we can install a unit onto? It’s very important to check that as well:
4. Window Width And Height Requirements
There are many different window shapes and sizes. When buying a small window AC unit for a small room, you have to know that the window will satisfy the window AC installation requirements.
Now, there are 2 types of window AC units, as far as the shape and the consequent window dimension requirements are concerned:
- Regular window AC units. These are the units where the width dimension is bigger than the height dimension. Examples would be #1, #2, #3, and #4 window AC units in the list below. These units require about 22-36 inch window width, and at least a 13-inch window height. You use a window AC kit to seal off the space the unit creates.
- Narrow window AC units. These units are tall; they do have a thinner width dimension. They are perfect for casement or vertical windows; the #5 PerfectAire 3PASC10000 is a clear example of a small narrow window air conditioner. In this case, the window width can be as little as 15.5 inches (compared to 22+ inches for regular window AC units), but you will need a window height of 22 inches or more.
To install a small window AC unit onto the window sill and seal off the space beneath the window (the window opening), you should always get a window AC kit (it usually comes along with the purchase of a unit, but not always so be sure to check that).
What happens if the window width is below 15.5 inches?
Well, there are no 15-inch wide window air conditioners or 12-inch wide window air conditioners. That window is just to narrow to install a window AC unit; the best alternative are portable AC units. Portable air conditioners are vented via a 6-inch round hose and that will fit through pretty much any window.
Let’s look at noise levels:
5. Noise Levels Of Small Window AC Units
If you are looking for a small window air conditioner for a bedroom, you would obviously prefer a quiet little window AC unit. These units can quickly cross 60 dB. According to the CDC, “normal conversation is about 60 dB”.
Now, smaller window AC units will have, on average, lower noise levels. That’s because you need a little compressor (main source of noise) and less airflow (CFMs).
Small window AC units with 50 to 60 dB noise levels are pretty much the standard. If you check the #1, #2, and #3 5,000 BTU units is the chart below you can see that all of them fall within the 50-60 dB noise levels.
The exceptionally quiet window AC unit is the #4 Midea U-Shaped MAW10V1QWT with a 42-51 dB noise output. In addition to being the most energy efficient, this is also the quietest small window air conditioner.
Alright, the last thing you should have a good idea about is the price:
6. How Much Should You Pay For A Small Window AC Unit?
When buying the smallest 5,000 BTU window air conditioner, don’t be fooled about the price. We have seen prices of $400+ for such units. That’s nonsense.
A small 5,000 BTU window air conditioner costs about $200. Sometimes even less, but hey, this is the high inflation 2023 season, the prices of 5,000 BTU can rise to $250 but that’s it. All 3 window AC units with 5,000 BTU cooling output in the chart are prices below $250.
Spending $400 on a 10,000 BTU unit, however, is actually very reasonable. In fact, some 10,000 BTU units can cost up to $600. In the comparison chart, you actually have two 10,000 BTU window AC units that have an above-average price tag (not unreasonably so):
- #4 Midea U-Shaped MAW10V1QWT costs about $450. This is a new U-shaped design, and you are paying for the quietest and most energy-efficient small window AC.
- #5 PerfectAire 3PASC10000 can cost above $500. This is one of the few viable small narrow window AC units in production. Because these narrow units that fit vertical windows are a bit of a niche product, they come at a bit higher price.
Alright, considering all these factors and metrics, let’s finally have a look at the list and comparison of the 5 smallest window AC units, complete with the individual reviews below the chart:
List Of 5 Smallest Window AC Units
1. Absolute Smallest Window AC Unit: Frigidaire FFRA051WAE
|Cooling Capacity:||5,000 BTU|
|Energy Rating:||11 CEER|
|Dimensions (DxWxH):||15.25 x 16 x 12 Inches|
|Volume:||2,928 Cubic Inches|
|BTUs Per Volume:||1,71 BTU Per Cubic Inch|
|Window Width (Min – Max):||23 – 36 Inches|
|Minimum Window Height:||13 Inches Or More|
|Noise Levels:||52 – 55 dB|
|Max. Airflow:||140 CFM|
Frigidaire FFRA051WAE has been, is, and will likely be the smallest window air conditioner in the future as well. This is the classic mechanical 5,000 BTU window AC unit without the extra baggage newer digital units have. It’s the tried-and-tested world’s smallest window AC unit you can get for less than $200.
Frigidaire FFRA051WAE is, as all 5,000 BTU units, a very small single-room window AC unit for small rooms up to 150 sq ft. This includes 10×10, 12×12, 10×12, and 10×15 rooms,
Dimensions-wise, it’s incredibly small. It is 16 inches wide and 12 inches high, and only 15.25 inches deep. It has an outstandingly smallish total volume of less than 3,000 cubic inches (2,928 cubic inches, to be exact). With the 1,71 BTU per cubic inch, it is also one of the most compact window AC units, outdone only by the #4 Midea U-Shaped MAW10V1QWT 10,000 BTU unit’s also $250 more expensive.
With the 11 CEER rating, it has an above-average energy efficiency within the 60°F to 90°F operating temperature.
It has two speeds. At low speed, it will produce 110 CFM (motor spinning at 1,210 RPMs) and will produce 52 dB of noise (fairly quiet). At high speed, it will produce 140 CFM (enough to homogeneously cool rooms up to 150 sq ft; motor spinning at 1,540 RPMs) and will produce 55 dB noise levels.
To install it, you need a window with 22-36 inch width and 13+ inches height. You get a 78-inch power cord that you just plug into a standard 110/120V outlet; that’s all that you have to do to install it. Here is a link to the specification sheet with all the metrics.
Overall, it’s not surprising that the Frigidaire FFRA051WAE is so popular.
It is the tried-and-tested smallest possible window AC unit with 5,000 BTU output, fairly low noise levels, amazingly compact (1,71 BTU per cubic inch) and costs less than $200 (you are not overpaying for new tech, it’s a reliable old school model that works splendidly):
2. Very Small 5,000 BTU Window AC Unit: hOmeLabs HME020003N
|Cooling Capacity:||5,000 BTU|
|Energy Rating:||11 CEER|
|Dimensions (DxWxH):||12 x 16 x 15.4 Inches|
|Volume:||2,957 Cubic Inches|
|BTUs Per Volume:||1,69 BTU Per Cubic Inch|
|Window Width (Min – Max):||23 – 36 Inches|
|Minimum Window Height:||13 Inches Or More|
|Noise Levels:||52 – 56 dB|
hOmeLabs HME020003N is a new extra small 5,000 BTU window AC unit from the up-and-coming hOmeLabs manufacturer. It is very similar to the #1 Frigidaire FFRA051WAE size-wise and other specs-wise with a bit more modern look. You have to look at these window AC units all day, so the aesthetic factor here is not insignificant.
Like #1 Frigidaire FFRA051WAE, the #2 hOmeLabs HME020003N is an ultra small 5,000 BTU model with up to 150 sq ft room coverage. You also have the same 11 CEER rating (energy efficiency) as well as 52-56 dB noise levels, comparable to the smallest Frigidaire window AC unit.
It is 16 inches wide and 15.4 inches high (this is a bit more than Frigidaire 5,000 BTU unit). However, it has a smaller depth dimension of only 15.25 inches. The total volume is 2,957 cubic inches (still below 3,000 cubic inches, quite astonishing). Due to these minimum dimensions, it has a very high 1,69 BTU per cubic inch compactness factor as well.
It’s priced at a bit more than $200, but hOmeLabs gives out discounts (usually about 10%) that drop the price below $200.
All in all, the hOmeLabs HME020003N is basically a better-looking version of the smallest Frigidaire window AC unit. It has below 3,000 cubic inches total volume, is very compact, has fairly low noise levels, and it actually has a nice-looking clean design:
3. Smallest GE Window Air Conditioner: GE AHEC05AC
|Cooling Capacity:||5,000 BTU|
|Energy Rating:||11 CEER|
|Dimensions (DxWxH):||15 x 16.44 x 12.56 Inches|
|Volume:||3,097 Cubic Inches|
|BTUs Per Volume:||1,61 BTU Per Cubic Inch|
|Window Width (Min – Max):||21.88 – 36 Inches|
|Minimum Window Height:||13.38 Inches Or More|
|Noise Levels:||50 – 59 dB|
|Max. Airflow:||143 CFM|
GE AHEC05AC is another good option for a very small 5,000 BTU window air conditioner. Compared to #1 Frigidaire and #2 hOmeLabs units, the GE AHEC05AC can be installed on narrower windows (min. window width is 21.88 inches compared to the 23 inches those two units require).
Specs-wise, GE created a very similar unit that Frigidaire came up with first, followed by hOmeLabs as well. The GE AHEC05AC is a 5,000 BTU window AC unit that can cool rooms with up to 150 sq ft square footage. The 143 CFM airflow ensures that the cool air will reach every part of that room.
The biggest limitation of these small window AC units, however, is the 23+ inch window width requirement. The GE AHEC05AC shaves more than an inch off that requirement; you can install it in a window that is 21.88 inches wide. The unit itself is 16.44 inches wide and 12.56 inches high.
The total volume of GE AHEC05AC is 3,097 cubic inches (more than 3,000 cubic inches). This makes it a bit less compact than the #1 Frigidaire and #2 hOmeLabs units with still a compact 1,61 BTU per cubic inch.
It also has a little higher noise levels at high fan speed setting (50 dB and up to 59 dB, to be exact).
All in all, the GE AHEC05AC is another reliable below $200 ultra small 5,000 BTU window AC unit. It is a bit larger than #1 and #2 units on the list but it has all the right specs at the affordable price point:
4. Best Smallest 10,000 BTU Window AC Unit (Quiet, Energy Efficient): Midea U-Shaped MAW10V1QWT
|Cooling Capacity:||10,000 BTU|
|Energy Rating:||15 CEER|
|Dimensions (DxWxH):||21.9 x 19.17 x 13.26 Inches|
|Volume:||5,567 Cubic Inches|
|BTUs Per Volume:||1,80 BTU Per Cubic Inch|
|Window Width (Min – Max):||22 – 36 Inches|
|Minimum Window Height:||13.75 Inches Or More|
|Noise Levels:||42 – 51 dB|
|Max. Airflow:||258 CFM|
Where to start with the Midea MAW10V1QWT? It’s quite difficult to stress just how superb and well-rounded a unit this is. Overall, we can definitely say this is the most energy efficient, most compact quietest small 10,000 BTU window air conditioner.
Now, the smallest window AC units will have 5,000 BTU cooling output. Midea MAW10V1QWT with 10,000 BTU is, obviously, not the smallest. However, it is incredibly small for a powerful 10,000 BTU unit, making it the smallest 10,000 BTU window air conditioner. Let’s look at the dimensions and the specs:
Midea’s window AC unit is 19.17 inches wide (that’s double the BTUs for additional 3.17 inches of width, compared to the 5,000 BTU units). It had a 13.26-inch height; that’s 1.26 inches higher than the #1 Frigidaire and #3 GE unit and lower than the #2 hOmeLabs unit. The less important depth dimension is quite long, 21.9 inches to be precise.
Midea is unique in that it has a U-shaped design. It sits on top of the window sill, thereby reducing that 13.26-inch height because most of the unit is located below the window sill itself.
With 1,80 BTU per cubic inch, it is also the most compact window air conditioner. It does have a bigger volume than 5,000 BTU units (5,567 cubic inches) due it also two times as powerful (10,000 BTU vs. 5,000 BTU). This means it packs a lot of cooling output is a relatively small case.
This is one of the best (if not the best of the best) window air conditioners in 2023. It has an outstanding 15 CEER rating (this is 36.3% more efficient than the 11 CEER rated units we have looked at thus far). It is the by far the most energy efficient smaller window AC unit.
You may have noticed that the first 3 5,000 BTU units had 50+ dB noise levels. Not one of them can be run at high speed without producing 55+ dB. Well, the Midea MAW10V1QWT has a 42-51 dB range. That makes it the quietest small window AC unit as well.
The added benefit of having a 10,000 BTU instead of a 5,000 BTU unit is that you can cool larger rooms (up to 450 sq ft) or several smaller 12×12 rooms, for example. Obviously, you have to keep the doors open in order for the good 258 CFM airflow to reach every corner of the rooms you want to cool down.
Due to new tech and incredible specs it brings, the price is a bit higher than the classic $400 for a 10,000 BTU window unit. It costs about $450 but that’s a well justified price, especially considering how much you are saving on electricity (incredibly low running costs).
All in all, if you are looking for a compact smaller window AC unit, the Midea MAW10V1QWT is the holy grail of window air conditioners. Incredibly energy efficient, silent, record-low height above the window sill due to U-shaped design, and so on. You can get it here:
5. Narrowest Window Air Conditioner: PerfectAire 3PASC10000
|Cooling Capacity:||10,000 BTU|
|Energy Rating:||10.4 EER|
|Dimensions (DxWxH):||23.5 x 14.75 x 21 Inches|
|Volume:||7,279 Cubic Inches|
|BTUs Per Volume:||1,38 BTU Per Cubic Inch|
|Minimum Window Width||15.5 Inches Or More|
|Minimum Window Height:||22 Inches Or More|
|Noise Levels:||56 – 61 dB|
|Max. Airflow:||323 CFM|
Now, a lot of people are asking: “What if I have narrow windows? Which small window AC unit will fit a thin window?” The answer is quite simple actually: The PerfectAire 3PASC10000. This is not the smallest window AC unit overall; but it is the narrowest.
The PerfectAire 3PASC10000 has a special thin design. Regular window AC units are engineered to have all the parts contained in a horizontal box. The PerfectAire 3PASC10000 has all the parts alined vertically. That does not reduce its overall volume (7,279 cubic inches, even above-average for a 10,000 BTU unit) but it significantly reduced the window width requirements for installation.
Namely, this window AC is only 14.75 inches wide. That means that the minimum requirement for window width is not 22-23 inches as we have seen with previous models. It is, in fact, only 15.5 inches. That means your window can be about 7 inches thinner than most other small window air conditioners.
When we check other specs, we have to take into account that these narrow window AC units are a niche product. They don’t have record-setting specs. For example, the PerfectAire 3PASC10000 has a 10.4 EER rating which is, well, average. It produces 56 to 61 dB noise levels which is a bit over average. The price of the unit itself can go over $500 as well.
These thin units are most useful if you have a vertical or casement window that you cannot fit any other window AC unit. Well, you can fit PerfectAire 3PASC10000 into it without problems (given that the window is at least 15.5 inches wide and 22+ inches wide). Here’s a show review and a link to the store where you can get it:
We hope that this overview of what it means for a window AC unit to be “small”, what metrics to check before buying a small window AC unit, and the selection of the units here will help you make the right choice. If you need any help, you can give us some numbers in the comment section below, and we’ll help you out.