How Does a Window Air Conditioner Work?

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Updated February 3, 2023

If you are new to the world of indoor cooling, you may wonder how does a window air conditioner work to cool the temperature in your home. Some of the best air conditioning units, after all, are window kits or feature a window-friendly design. So what are the benefits of choosing a window AC and how do they work? Keep reading to find out.


  • Window air conditioning units affix to an open window and cool air after pulling it in from the outside, otherwise known as the hot air cycle.
  • These AC units are energy-efficient, fairly durable, and particularly easy to install and use, with common parts like an expansion valve, condenser coil, and evaporator coil.
  • To maintain your window AC unit, clean or replace the air filters regularly and clean and maintain the exterior components.

How Window AC Units Operate

Window air conditioning units work similarly to many other types if you are wondering how does a portable air conditioner work. These AC units attach to a window, pull in outside air, and push out cooled air. This method of operation is also similar to tower AC units if you are wondering how a tower AC works.

Insider Tip

Before using your window unit each season, be sure to clean it inside or out to avoid foul odors.

Installing the AC varies from unit to unit, but beware as these appliances are heavy, if you learning how heavy window air conditioners are. Also, they may take a while at the start of each season to properly cool off your space, if you are learning how long air conditioners take to de-ice.

Benefits of Window Units

There are many benefits of choosing a window unit over a central air conditioning unit. First of all, window ACs are more energy-efficient than central units as they are designed to merely clean one room. They are also much easier to purchase and install. One final benefit of window ACs is that modern units often come with modern features if you want to know if your AC is compatible with Alexa.

STAT: Generally speaking, a window AC needs 20 BTU (British Thermal Units, a measurement of cooling capacity) to cool one square foot of space. Multiply the length of the room by the width and then multiply that number by 20. (source)

Maintaining a Window AC

You should properly maintain your window unit to ensure a decent lifespan, so you won’t have to know how to make an air conditioner with a fan. Here are some must-learn window air conditioner maintenance tips.

  • Only use when necessary – To keep your energy costs down, only use your window AC when necessary. In other words, if you are not going to be in the room any time soon, shut it off and wait until you enter the space and want it cooled down.
  • Clean or replace filters – All air conditioners feature air filters of one kind or another. Make sure to clean or replace these filters regularly according to the manufacturer’s instructions. If they are reusable, clean them every month, otherwise replace them every two to three months.
  • Clean the exterior – Take the time to clean and wipe down the exterior and the various components regularly to ensure a good lifespan.


What’s the thermostat do?

The thermostat lets you know how cold it is in your space, measured at a nearby window near the window frame or window sill.

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

Take a look at the unit’s BTUs, otherwise known as British thermal units. Also, look at a. portable air conditioner or two as an option. Finally, check out your window size before making a purchase, as window types like a double-hung window may require a specific AC design.

Does a window air conditioner pull air from the outside?

They sure do. During the hot air cycle, the window air conditioner unit pulls in air from the outside and cools it via a condenser coil. This is true for portable units also.

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