How Does a Wall Air Conditioner Work?

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Updated May 17, 2023

If you’re looking for a premium air conditioner and comparing various models, you may wonder, “How does a wall air conditioner work?” Wall units have a similar cooling capacity as window AC models, but they are permanent installations that save on window space. In addition, they are energy-efficient and can cool more square footage than other non-central air conditioners. Product experts also refer to wall AC units as ductless air conditioning systems or mini-split air conditioners. These models split the workload between an indoor and outdoor unit connected through the wall.


  • Wall air conditioners, also called through-the-wall AC, are a type of ductless air conditioning system.
  • Users must drill a hole in the wall of their home to install a window AC unit.
  • A wall AC system removes hot air from your home and replaces it with cool air from outside.

Understanding Wall AC Function

Before deciding on a cooling solution, read this guide to learn more about through-the-wall air conditioners. If you want to understand the possible cooling power with a wall AC unit, consider reading our reviews of the LG LT1037HNR or the Tosot 8000BTU window air conditioner.

Also, check out our article on how tower AC works if you’re curious about alternative air conditioning equipment. The type of unit you have will determine maintenance factors, like thawing the AC unit or replacing a power cable.

Insider Tip

The cooling process will take much longer if you don’t close the doors and windows to your home.

To make how to set the thermostat easy, some thru-wall AC models have a remote control to select the perfect temperature. In addition, you want to install a slide-out AC chassis to support the unit’s weight, which is similar to installing a window air conditioner bracket.

Indoor Unit

The indoor unit goes on the room wall or section you want to cool. This unit takes in the hot air and distributes heat and moisture in the conduit. The conduit utilizes refrigerant tubing, a condensation drain, and a power cable to move the heat and moisture from inside your house or apartment. All this can be done quietly and leave you in piece if you get the quietest wall air conditioner.

Outdoor Unit

The outdoor part, also known as the condenser, takes the heat and moisture from the conduit and passes it to the outdoor air. This unit uses a sleeve to mount to the exterior wall of your home.

STAT: The first residential air conditioning unit was installed in 1914 and cost between $10,000-$50,000. That’s between $250,000 and $1.3 million in 2022 dollars. (source)

Is the Through-Wall Installation Process Easy?

While the wall air conditioner’s installation process is straightforward compared to a central air conditioning system, you need some serious equipment for a secure fit. You need a drill and saw to make a hole in your wall, either for a slide-out chassis or sleeve.

Experts recommend that users place the wall AC unit about 6 ft high and free from any obstructions like furniture or plants. In addition, have a friend help you lift the unit into position because standard-sized AC units can be heavy.


If you do not use a sleeve with your wall AC unit, you will damage the exterior wall of your home and possibly the window air conditioner.


Do Through the Wall Air Conditioners Need a Sleeve?

Wall sleeves help support the weight of your wall model. If you don’t use a sleeve, the window air conditioner can buckle or deform your wall, causing the AC unit to fall. Luckily, a modern wall-mounted ac unit should come with a slide-out or built-in sleeve.

Can I use my air conditioner too much?

Modern air conditioners can run for a long time without issue, so you can keep your space cool without concern. If you’re concerned about energy bills, you can enjoy significant energy savings by running a cool air cycle until you reach a comfortable temperature.

Is a wall AC better than a window AC?

Since a thru-wall air conditioner is a permanent installation, they typically offer additional modes and convenience features than window AC units. In addition, wall machines provide better energy efficiency than window AC models since they are built through the wall. You may lose cool air through leaks between the window unit and the window sill.

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