Man installing a through the wall air conditionerDo you need a crash course on how to install a through the wall air conditioner?

If so, this guide can help.

We’ll explain the general steps necessary for how to install a wall AC unit so you can start enjoying your new air conditioner right away.

The process is not as hard as you may think, but it will take a bit of preparation and some patience to get the job done right.

So, let’s get started.

Why Should You Get a Through The Wall Air Conditioner?

If you’ve already purchased your through the wall air conditioner, then you can skip this section.

However, if you’re still in the researching phase and want to know what’s involved with installing this type of air conditioner before you buy it, then this short section is for you.

Over the last few years, through the wall air conditioners have risen more in popularity.

These appliances now rival both window air conditioners and portable air conditioning units because of their low cost, cooling capacity, and permanent installation.

We’ll get into the list of benefits that through the wall air conditioners offer next, but if you do find that this is the right solution for you, we invite you to check out our best through the wall AC unit buying guide. There, we explain everything you need to know to choose the perfect device for your needs and budget.

The top three benefits of wall AC units include:

  • Energy Efficiency — The average size through the wall air conditioner doesn’t use much energy to operate. This keeps your electric bill low and more money in your pocket. Many people pay around $20-30 per month to run the unit.
  • Long Term Solution — Since these appliances are built into a wall, you get a permanent solution for your air cooling needs. The problem with other air conditioners, like window AC and portable AC units, is that you have to uninstall them and store them during the winter. That can be a hassle for some people.
  • Double as a Heater — Some wall air conditioners provide supplemental heat in addition to air conditioning. This gives you year-round comfort for the lowest cost.

How To Install A Through The Wall Air Conditioner

Tools Required

Before you actually install your through the wall air conditioner, you need to acquire all of the right tools.

Doing so will ensure that your installation runs smoothly and goes as quick as possible.

Here’s a checklist of the items you’ll need to install this device:

  • Sleeve (Also called “bracket” and should come with your purchase. If not, make sure to buy one.)
  • Caulking Gun
  • Silicone Caulk
  • Measuring Tape
  • Stud Finder (or you can use a small penny nail for finding the studs)
  • Paint
  • Pencil
  • Pry Bar
  • Circular Saw
  • Hand Saw
  • Hammer
  • Nails
  • Level
  • Several 2 x 4 pieces of lumber (for framing)
  • Drills and drill bits
  • Utility Knife
  • 1 sheet of drywall
  • Drywall compound
  • Drywall Knife

Step 1: Choose a Spot

Take a good look around the room that you want to install the through the wall air conditioner in choose a good location for it.

Consider spots that have the most aesthetic appeal and where you think it will have the most impact. And, keep it close to an electrical outlet so you can plug the unit it after installation.

Also, plan to keep the bottom of the wall AC unit about 1 to 5 feet above the floor. This will minimize the amount of dust that the air filter collects from the floor and prevent condensation from forming on the ceiling if it was to be installed too high.

Step 2: Mark the Wall Studs

Walls are built and supported by wall studs (2 x 4 lumber) and they’re usually 16 inches apart.

After you select a location for your appliance, you need to mark the studs so you know where you can start cutting through the drywall. Also, you want to reduce the number of wall studs you have to remove to make the job easier.

You have two options here:

  1. Using a stud finder to accurately identify the studs.
  2. Tapping on the wall with your knuckles to find a spot where the sound changes from hollow to solid. Then, hammering a small penny nail into the wall to confirm the right location. If you hit a stud, good. If not, try again.

Once you locate 3-4 wall studs, mark them on the drywall with an X using a pencil.

Then, measure the width of your through the wall air conditioner and transfer that measurement to the wall where the studs were marked. Your appliances should also have come with an installation guide that you can tape onto the wall and trace its outline. If not, use the sleeve (bracket) to for this purpose.

Position the guide paper or sleeve so that you cut through the fewest number of studs possible.

Step 3: Turn Off Power to the Room

Locate your house’s electrical panel (breaker box) and flip the breaker that controls the power to the room. You’re going to be cutting through the wall in the next step and you don’t want to accidentally cut through electrical wires and get shocked.

To power your saw and drill, run an extension cord from another room that still has electrical power.

Step 4: Making the Hole

Using the supplied guide paper or sleeve, trace around the outline so you can mark the opening for the air conditioner on the wall.

Make sure that your outline is level by using your level tool during the marking process.

Then, make another outline that’s 2 ½ inches larger than the existing outline. This will give you enough extra room to build a supporting frame for the unit out of the 2 x 4 lumber pieces.

Next, take your drywall knife score the outline. Also, score vertical lines above the wall studs.

Then, use a hammer to knock the center of the scored drywall sections so that they pop out. Alternatively, you could use a hand saw to cut through these pieces of drywall instead of hammering them out.

Extract all of the drywall pieces so you now only see the wall studs. If there is insulation in the wall, cut those pieces out as well to match the opening you made in the wall.

Step 5: Cut Through the Wall Studs

Using a circular saw, cut through the wall studs that are inside the wall opening so that they are flush with the outline.

Step 6: Construct a Frame for the Air Conditioner

Measure the width of the wall opening and transfer that measurement to (2) 2 x 4’s and cut them down to the matching length.

Measure the height of the wall opening and subtract the combined thickness of the 2 x 4’s you just cut. Then, cut those down to the matching lengths.

Put those four pieces of 2 x 4 lumber together to make a frame. Nail them all together.

Slide this 2 x 4 frame you built into the wall opening and secure it in place by nailing what you can into the wall studs.

Step 7: Create a Hole In The Exterior Wall

Use a drill to make a hole in each of the four corners of the interior frame that punches through the exterior wall.

These holes will serve as a guide to help you measure exactly where you need to cut on the exterior wall.

With your pencil and a level, draw four straight lines to connect these drill holes on the exterior wall.

Then, using the circular saw, cut the exterior material so that you now have a perfect match between the interior and exterior holes.

Step 8: Installing the Through the Wall AC Unit

Slide the metal sleeve (bracket) into the wall opening and secure it in place according to the instructional manual.

Insert the device into its sleeve and secure it into the bracket.

Plug the power cord into the closest electrical outlet.

Step 9: Completing the Installation

Use the new drywall to cut and patch any exposed areas around the appliance.

Nail it in place with drywall nails.

Touch up any gaps or holes using drywall compound and the drywall knife.

Prime and paint the drywall so that it matches the existing wall color.

Use the caulking gun and silicone caulk to put a thick bead of caulk around the edges of the unit on the interior and exterior of the house. This will prevent any air from seeping in our out of the home.

For a more finished look, you can install trim or molding around the unit to suit your taste.

Step 10:  Turn the Power Back On

Flip the breaker back on for the room, so that that power returns to the room.

Then, turn your air conditioner on and enjoy the cooling comfort.

How Much Do Through The Wall Air Conditioners Cost?

Now that the installation guide is over, some of you who don’t already own a through the wall air conditioner may be wondering how much these units cost.

As you’ll see in our best through the wall AC unit buying guide, the total costs for buying the unit and operating it each month really depends on how large a room you need to cool.

Here’s what you can expect from the most efficient wall air conditioners:

Through the Wall Air Conditioner Total Cost Chart

Room Size CoverageCapacity NeededPriceMonthly Cost
300 up to 350 sq. ft.8,000 BTU$430$20.88
350 up to 400 sq. ft.9,000 BTU$450$25.31
400 up to 450 sq. ft.10,000 BTU$470$28.57
450 up to 550 sq. ft.12,000 BTU$500$31.80
550 up to 700 sq. ft.14,000 BTU$600$41.13
700 up to 1,000 sq. ft.18,000 BTU$800$47.46

We hope you enjoyed this guide on how to install a through the wall air conditioner as well as the information about total costs for these units.

As you can see, the installation process is not too difficult as long as you have all of the necessary tools and take the proper steps. And, owing a wall AC unit is a great way to enjoy cooling comfort without spending a lot of money.