Making a Cover for a Window Air Conditioner

What You'll Need
Measuring Tape
Graph Paper
Foam Boards
Plastic Sheets
Construction adhesive
Razor Knife
Thermal Insulator
Reflective Foil

A window air conditioner cover is an excellent way to prevent cold air from leaking into your house during the winter. This cold air can be an added drain on your finances. As the air conditioner sits in the window, it is hard to seal the window from winter’s chill, making the heater work twice as hard and increasing your electric bill. A cover will seal the window. You can make an indoor or outdoor cover. If you are ambitious, you can make both.

Step One- Clean Debris

Before you seal the outside part of your air conditioner, you need to clean out the debris. You can do this with a high pressure hose or your hands; just get out as much gunk as possible.

Step Two- Measurements

Before you begin cutting, you need to know the dimensions of your air conditioner. Jot down the height, width and depth of the outside element and sketch it.  In this sketch be sure to include the location of any hardware.

Step Three- Cutting 

Use the razor knife and cut the Styrofoam into five parts. Each part should have slightly larger measurements than the side of the air conditioner it corresponds to. There should be about an eighth of an inch of leeway in the final product. This will ensure that, while the cover will fit on the machine, it will be snug. Be sure you account for any hardware.

    Step Four- Assembly

    Use the construction adhesive to form a box. This box should have slightly larger dimensions than the outside portion of the air conditioner. Once the box is completed, place it on the air conditioner and seal it. There should be no room for the air to enter of escape the building. The adhesive you use should specify that it will not peel the paint on your house.

    Step Five- Plastic and Thermal Insulation

    It is now time to move to the inside of your house. Measure the window and cut a piece of plastic that will be slightly larger. Use the constructive adhesive to attach the plastic to the wall. It should be airtight. Using the same dimensions cut a piece of thermal insulation and adhere it to the plastic. This will help prevent warm air from escaping.

    Step Six- Finishing Up

    Cut the reflexive foil so that it will fit over the insulation and adhere it to the wall. This will reflect heat back into the room. Remember, you do not need to make both covers; either will help keep the heat in and the cold out. However, it is very important that the cover is airtight. If it is not, you may suffer unpleasant drafts throughout the winter.