Installing a Through-the-Wall Air Conditioner Installing a Through-the-Wall Air Conditioner

What You'll Need
Pencil
Measuring tape
Drywall knife
Utility knife
Circular saw
Pry bar
Lengths of 2-by-4 or 2-by-6 lumber
Air conditioner unit
Drill and drill bits
Caulking gun
Silicone caulk
Paint

Installing a through-the-wall air conditioner unit is a cost effective idea for a medium sized room that lacks any form of cooling.  Prior experience in carpentry will make the work easier, especially since your appliance installation will require you to make a hole through a wall.

Follow these steps to successfully install a through-the-wall air conditioner to cool a medium sized room, or several small sized rooms that are close together.

Step 1 – Select a Suitable Place

Walk the length of the room to choose a suitable place. Ideally, an air conditioning unit should be placed under a window so the header can support its weight. Also make sure there is an electrical outlet with the appropriate voltage nearby. There should be no electric or gas lines wired below the window.

Step 2 – Make a Hole in the Interior Wall

Measure your air conditioning unit or check the manual for exact dimensions. Air conditioners vary in size and weight, so an exact measurement is necessary.  Use a pencil to mark the measurements on the wall where you want to make a hole, adding 2 ½ inches on the top and a ½ inch to both the sides.

Cut the drywall carefully with a drywall knife right down to the baseboard and vertical support. Make sure there are no pipes through the hole and remove any insulation in the hole with a utility knife. Remove the drywall with pry bar and set it aside.

Step 3 – Build an Air Conditioner Frame

Build a frame for your unit under the window using lengths of either 2-by-4 or 2-by-6 lumber according to the width of the exterior wall. Measure them to make sure they fit the air conditioner before you cut them with a saw.

Step 4 – Make a Hole in the Exterior Wall

Drill holes on the four corners of the frame from inside the wall to the exterior. Using these holes as a guide, draw four straight lines on the exterior wall to mark where you need to cut. Cut the exterior wall section with a circular saw.

Step 5 – Install Air Conditioner

Slide the air conditioner bracket into the hole and mount it securely with screws. Insert your air conditioning unit into the bracket, tilting it a bit to ensure good drainage. Drill holes to the sides of the hole to secure the unit extensions. Attach the drainage hose to the outside.

Step 6 – Complete the Unit Installation

Use the drywall that you removed earlier and cover any exposed portions around the air conditioner unit to prevent cool air from escaping outside. Measure the area of the gap and cut your drywall to fit it perfectly. Hammer it into place to create a tight seal and apply a coat of paint the same color as the wall. 

Caulk the area on the exterior wall around the air conditioner unit with silicone, which is strong enough to withstand weather changes and unit vibrations. Switch your through-the-wall air conditioner unit on to enjoy the cool air.

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