Minimum Width For Window AC of 5000-24000 BTU

Narrow windows make installing a window air conditioner impossible in some cases or at least a challenge.

This page explains how wide your window must be for standard and casement window ACs.

Plus, narrow window AC brands and models are listed from 14 to 21 inches – something you won’t find anywhere else.

Do 11 Inch Wide or 12 Inch Wide Window Air Conditioners Exist?

Unfortunately, the answer is no – 11” wide window air conditioners and 12” wide window air conditioners are not manufactured.

We know because Pick HVAC researchers have checked every model from every major brand like LG, Frigidaire, GE, Midea, Hisense, Friedrich, Danby, Whirlpool, Della, Haier and Keystone.

What is the Minimum Window Width for Window AC?

About 14 inches is the minimum window AC width, but read on for details, because there are two styles of window air conditioner to consider. A window AC 14 or 15 inches wide probably won’t fit in your single-hung or double-hung window because it might be too tall.

Most window air conditioners need a significantly wider space. As the size in BTUs of the units increase, their cabinets get bigger, and a wider window is required.

What about side panels? Those are the “wings” that extend to the side to fill the gap between the AC and the window frame. Most sets are at least 3 inches wide, and so you should factor in that extra width when buying a window air conditioner.

Or you can take them off and set the AC into the window frame. If a gap remains, you can fill the gap using a range of materials like plastic sheet and tape or foam insulation.

Easy DIY tips:

1). Remove the side panels, if necessary. Most of the side panel wings can be removed by sliding them out of the tracks on top and bottom. Simple. A few are held in place by small screws – nearly as simple to remove the screws and lose the panels!

2). DIY window AC foam insulation panels that you can cut to size are available too, like this quality foam set. It is also available in black.

Casement Window AC vs Common Window AC

What is the difference between a common window AC and a casement window AC? There are two dimensions to consider.

Standard window ACs fit in sash windows, which are single-hung or double-hung windows with a lower sash that raises.

Standard or common window air conditioners start at about 16 inches wide, though most need a window at least 21 inches wide. For example, the Toshiba RAC-WK0511CMU listed in the chart below is slightly less than 16” wide.

A more common size is the LG 6000 BTU 11.5 EER window air conditioner that requires a minimum window opening of 21”.

These ACs are wider than they are tall. For example, the LG 6000 BTU unit just mentioned as needed 21 inches of width only needs 12 inches of height. For larger units, the minimum height for the opening is 23 to 30 inches.

Casement window ACs are narrower, designed for use in casement and sliding windows. The narrowest we’ve found is a Keystone 8000 BTU Slider/Casement window AC requiring a minimum window opening of 15.5 inches.

DIY tip: Keep in mind that you’ll have to fill the space above the AC in a sliding or casement window. Most casement window air conditioners come with some sort of panel or filler, but you might have to DIY using plastic sheeting or foam. You can also use the panels linked to above – and stack them rather than putting them on each side of the AC. Yes, you’ll have to cut them to fit, but they work great and are insulated to save energy loss.

They are taller than standard window ACs. The Keystone 8000 slider/casement AC needs a window height of 21.3 inches.

Narrowest Window ACs Available in 2023

OK, this is what many readers are here to discover – what are the skinniest window air conditioners made today? Let’s go inch by inch, almost, starting with those just slightly wider than 14 inches.

14-inch Wide Window Air Conditioner

Cooling Capacity Room Size Available Brand & Models Samples
8000 BTU 350 sq ft Frigidaire Casement FFRS0822SE (14.2 inch)
10,000 BTU 450 sq ft Frigidaire Casement FFRS1022RE (14.2 inch)

There are two great options at 14.2 inches if you remove the side panels. Both are made by Frigidaire, one of the most reliable brands of air conditioner.

Important – These are casement and slider window ACs, and they are likely too tall for most single-hung and double-hung windows.

Is there any 5000 BTU 14-inch wide window AC?

No. But you could consider using one of the units in the chart above and running the unit on the Low setting.

What is the smallest cooling size for a 14-inch wide window AC?

8000 BTU according to the chart above – but keep in mind it is 14.2 inches, just a little wider than 14 inches.

What is the maximum cooling size a 14-inch window ac can cool:

10000 BTU. That is the largest capacity casement window air conditioner that is near 14 inches – it needs 14.2 inches of space.

Did you know? These days, most new single-hung and double-hung windows start at about 14.5 inches wide, so an AC that is 14.2 inches will fit if you take off the side panels. However, yes, there are a few narrower ones out there. Most were used in bathrooms, but some were put in bedrooms and offices where a window AC is desired.

Is there a 14-inch wide window AC that is not Casement type?

No. Standard window ACs start at around 16 inches. See the 16-inch wide window AC chart below for details.

15-inch Wide Window Air Conditioner

Cooling Capacity Room Size Available Brand & Models Samples
8000 BTU 350 sq ft Keystone KSTSW08A Casement 14.75 inch

Is there any 5000-6000 BTU 15-inch wide window air conditioner?

No. But again, the Keystone model in the chart will fit a 15-inch window and can be run on the Low setting if necessary to avoid over-cooling the space.

What is the smallest cooling size for a 15 inch wide window AC?

8000 BTU.

Are there any 15 inch wide window air conditioners that are not casement window ACs?

No. You’ll need to go to 16 inches to find standard window AC models – not casement window ACs.

16-inch Wide Window Air Conditioner

Cooling Capacity Room Size Available Brand & Models Samples
5000 BTU 150 sq ft Toshiba RAC-WK0511CMU 16 inch, Keystone KSTAW05BE 16 inch, Keystone KSTAW05CE 16 inch, Midea MAW05M1WWT 16 inch, Midea MAW05M1BWT 16 inch, GE AEL05LX 16 inch
6000 BTU 250 sq ft Frigidaire FFRA062WAE, Danby DAC060EE1WDB 16 inch

Now your options are broadening!

What is the maximum cooling size for a non-casement window air conditioner?

6000 BTU for a 16-inch window.

What is the maximum room size a window AC can cool if my window is 16 inches wide?

550 sq ft. You can choose a narrower casement window AC like the Frigidaire FFRS1022RE, which is only 14.2 inch wide. But remember that the window opening height might be a concern if the window is not a casement or sliding window.

19-inch Wide Window Air Conditioner

Cooling Capacity Room Size Available Brand & Models Samples
6,000 BTU 250 sq ft Keystone KSTAW06BE 18.5 inch
8,000 BTU 350 sq ft Danby DAC080EE2WDB 18.6 inch
10,000 BTU 450 sq ft Danby DAC100EB6WDB, Midea MAW10S1WWT
12,000 BTU 550 sq ft Danby DAC120EB6WDB-6, Midea MAW12R1BWT
14,500 BTU 700 sq ft Danby DAC145EB6WDB-6

What is the maximum cooling size for a 19 inch window air conditioner?

14,500 BTU. And the Danby DAC145EB6WDB-6 is a very good option.

What is the maximum room size a 19 inch wide window air conditioner can cool down?

750 sq ft.

20-inch Wide Window Air Conditioner

Cooling Capacity Room Size Available Brand & Models Samples
5,000 BTU 150 sq ft Kapsul W5
8,000 BTU 350 sq ft Kenmore 77080 8,000 BTU 115V
10,000 BTU 450 sq ft Frigidaire Gallery GHWQ103WC1
12,000 BTU 550 sq ft Frigidaire Gallery GHWQ123WC1
14,000 BTU 600 sq ft Haier QHEK14AC, GE AHEK14AC

What is the maximum cooling size for a 20 inch window air conditioner?

14,000 BTU.

What is the maximum room size a 20 inch wide window air conditioner can cool down?

650 sq ft.

Minimum and Maximum Width for Window AC Units with Specific Capacity

CapacityMinimum WidthMaximum Width
5,000 Btu15.98"20"
6,000 Btu15.98"21.42"
8,000 Btu14.20"(casement)/18.50"25.94"
10,000 Btu14.20"(casement)/18.50"25.94"
12,000 Btu18.98"25.94"
14,000 Btu18.9"23.63"
15,000 Btu19.76"25.98"
18,000 Btu19.76"25.98"
23,000 Btu25.5"28"
24,000 Btu25.98"28"

Window AC Alternatives if Your Window is 12 Inches Wide, 11 Inches Wide or Less

Are the narrowest window ACs still too wide? What other options are there?

Here are the best alternatives to a window air conditioner for windows 11 or 12 inches wide.

Portable Air Conditioners

These are units that sit on the floor and have wheels, so you can roll them from room to room. They have an intake and exhaust hose – some have dual hoses and are more energy efficient.

The only thing that must be installed in the window is a narrow panel that holds the hose or hoses in place for exhausting warm, humid air and bringing in fresh air.

“Pound for pound,” portable ACs are not as efficient as window ACs, but if you want air conditioning in a room with a narrow window, they’re your best choice.

Mini Split Ductless AC or Heat Pump

This is a permanent solution to a warm room, though it will cost more than a window air conditioner or portable AC.

However, if you need long-term AC in a bedroom, office or converted attic or garage, consider a mini split system.

AC-only mini split units are available, though most are heat pumps, so you’ll have the heat option for cold weather.

Evaporative Coolers

These can be room-size systems that cool the air through evaporating moisture off of a screen or other material type. Personal sizes are produced too. You might know them as swamp coolers or desert coolers.

That last name is instructive – evaporative coolers work best and are really only recommended for dry areas of the country. If the air in the room you want cooled is already humid, an evaporative cooler is not your best alternative to a window AC.

Check out the best room size and personal evaporative coolers available today!

Personal ACs or Personal Fans

Manufacturers use the term AC to market these personal fans.

This is a low-budget way to cool yourself in a warm, sticky room. Personal fans sit on the desk or bedside table, and blow air over you. It’s the way your grandmother cooled herself “back in the day,” and it still works today.

Cooling Tip – Find more alternatives to window air conditioners and tips for staying cool in our fun guide 20 Ways to Cool Down a Room Fast!

Written by

Rene has worked 10 years in the HVAC field and now is the Senior Comfort Specialist for PICKHVAC. He holds an HVAC associate degree and EPA & R-410A Certifications.

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