What is a Window Air Conditioner?

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Updated December 17, 2022

If you are new to the wide world of personal cooling, you may ask “what is a window air conditioner.” Some of the best air conditioners, after all, are window units. So what exactly are window AC units, why do people use them, and should you purchase one? Keep reading to find out.


  • Window air conditioners are a great option for cooling just a single room at a time, acting as a sort of portable air conditioner when compared to central units.
  • Window ACs work by pulling in air from the outside, running it through cooling coils, and spitting out cooled air into the space.
  • This type of air conditioning system is known for being efficient, with many Energy Star models available, easy to install, and easy to use with a packed-in remote control.

What Exactly is a Window AC?

As the name suggests, a window AC unit is an air conditioner that installs onto an open window. These appliances are great for cooling single rooms during those hot summer months and are used primarily by consumers without central air conditioning in their homes. So if you are looking for the best air conditioner for a sliding window, check out window units. In other words, if you wonder about the definition of a wall unit air conditioner, look elsewhere.

Insider Tip

No matter which you choose, make sure the AC is powerful enough to adequately cool your space.

How do Window Air Conditioning Systems Work?

These appliances work similarly to many other designs if you are wondering about the definition of an AC unit. Once you install it on the wall, the window unit pulls in air from the outside, runs it through cooling coils, and a fan spits the newly cooled air into the living space. This functionality is even similar to rarer AC designs if you wonder about the definition of a mechanical air conditioner.

Benefits of Window AC Units

There are many benefits to choosing a window air conditioner instead of central air conditioning and other types.

Energy Savings

Window units allow you to keep cool and save a bit of cash on your monthly energy bill, especially when compared to central units. These ACs only cool a single space, and not an entire home, so you pay only for the cooled area. Central air conditioning units, on the other hand, cool an entire home, so you’ll see much larger monthly energy bills.

Easy to Use and Install

Window air conditioners are known to be easy to install and easy to use, with few maintenance and repair issues. Installing a window unit involves opening the window, affixing the AC, shutting the window to fit, and filling in the side gaps. Use involves simply pressing the power button and the fan speed. When you compare this ease-of-use to central air conditioners that often fall victim to maintenance issues, it is a no-brainer of sorts. Keep in mind that not all in-wall units can also work within a window like the in-wall AC unit we feature in this LG LT1037 HNR review.


How do you pick the right window AC unit for your home?

Window air conditioners should be able to properly cool the entire room without too much of a struggle, all while adhering to Energy Star standards. Pick an energy-efficient AC that offers plenty of thermal units of cooling.

Do you need a “smart” AC?

An air conditioner with smart controls, such as voice control, is nifty but not exactly necessary. These window air conditioners still cool the same square footage and still cost the same to run, assuming they are Energy Star-compliant.

How to properly size a window air conditioner?

When it comes to window air conditioners, measure your windows first to ensure a proper fit. These types of air conditioners are often fairly universal in design and built to fit many types of windows.

STAT: The basic components of a window air conditioner include a thermostat, a fan or blower, tubing filled with refrigerant, a compressor, an evaporator coil, and a condenser coil. (source)

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