How to Install an In-Wall Air Conditioner

A single room air conditioner is great when only one room is heating up in the summer. If that room only has a few windows and you'd rather not use them with a window unit, try installing you own through-wall air conditioner.

Difficulty: Challenging

Instructions

Things You'll Need:

• Drill with boring bit
• Through-wall air conditioner
• Caulk

Prepare the Space for Your Through-Wall Air Conditioner.

1. Choose a space for your air conditioner. Try to find a space under a window to avoid needing a header to displace load. Windows already have a header. If you must put the air conditioner in a flat wall, that's OK. Find a space above the wall's electrical outlets.

2. Measure a space the size of the air conditioner you're using and add 2 1/4 inches to the top and 1/4 inch to each side. Use a pencil and a straight edge to draw the outline of the cutout in your wall. Cut the drywall away with a drywall knife and expose the insulation in the wall. Make sure there are no wires or pipes running through your hole. If there are, patch the hole and go back to Step 1. Remove the insulation in the hole with a utility knife. Remove the drywall down to the baseboard and to the next vertical support to either side.

3. Take a measurement from the base of the frame in the wall to the top of your hole and subtract 2 inches. Saw two 2-by-4-inch boards at this length. Fit each of these boards against the studs closest to the outside of the space for your air conditioner. Nail them into the base of the wall and the stud they're next to. There will be a gap above them. Don't worry because it should be there.

4. Cut another 2-by-4-inch board the length of the measurement between the two studs you reinforced with other 2-by-4-inch boards. Cut out the studs between them with a reciprocating saw, or remove them with a pry bar. Nail the new 2-by-4-inch board horizontally across the top of the reinforcement studs in the gap and into the original studs on either side. If you're using a load-bearing wall with no window, install a header instead of the 2-by-4-inch board.

5. Nail cripple studs between the header or 2-by-4-inch board and the top of your frame. Measure and cut them first. Saw two more 2-by-4-inch boards as long as the height that you want to set your air conditioner minus 2 inches. Nail the boards to the reinforced studs outside of your hole and the base of the frame. Measure another 2-by-4-inch board into a cross timber to cover the top of the shorter reinforcement studs.

6. Frame the sides of the hole in your wall with two more 2-by-4-inch boards. Allow 1/4 inch of clearance on either side of the hole from the measurements for your air conditioner.

Cut Through the Outer Wall and Install Your Through-Wall Air Conditioner

7. Bore through the wall from the inner side of the cutout in the wall to the outer side in each corner of your frame.

8. Remove the outer siding with a pry bar and reciprocating saw for the space between your bored holes as well as an area of about 6 inches on all sides.

9. Use the reciprocating saw from inside to saw through the outer wall and remove the section for your air conditioner. Install the air conditioner into the wall using the included bracket and hardware according to the manufacturer's instructions.

10. Caulk the space between the air conditioner and surrounding wall from the outside, and trim around the air conditioner inside.

Tips & Warnings

• It's important to support the air conditioner with the included bracket so the air conditioner drains to the outside. Otherwise it can cause water damage in your house.