Your window air conditioning unit keeps you comfortable and cool in the hottest months of the year. The biggest problem with the unit is that it doesn't coordinate well with any decor, no matter how you've decorated your home. If you can't remove the air conditioner from the window when it gets cold outside, you face a winter full of drafts and poor insulation. Sew a simple cover for your ugly air conditioner to make it good-looking when you're not using it, and keep the heat inside during the winter.
Measure the width and height of the air conditioner across the front. Measure the depth of the unit from the front to where it meets the window.
Determine the measurements for the fabric by adding twice the depth to the width of the air conditioner for the width of the fabric. Add twice the depth to the height of the unit for the length of the fabric. For example, if your air conditioner measures 20 inches wide, 15 inches high and 3 inches deep, add 6 to 20 inches, then add 6 to 15 inches, so you end up with 26 inches wide and 21 inches long. Add 1 inch to the width and 1 inch to the length, so the cover slides over the front of the unit with ease. In the example, you'll end up with 27 inches by 22 inches.
Cut two pieces of fabric equal to the measurements you computed in Step 2. Also cut a piece of insulated batting to the same measurements.
Layer the fabric and batting so that the batting is between the two pieces of fabric, right sides facing out. Pin the layers of fabric and batting together.
Sew the fabric and batting layers together. Stitch one row of stitches across the width of the fabric, 1 inch from the top edge. Stitch another row of stitches across the width, 1 inch from the first row of stitches. Continue to sew rows of stitches across the fabric until you are 1 inch from the opposite end.
Line up the inner fold of the bias tape with the raw edge of the fabric, starting at the bottom left corner. Position the bias tape over the raw edge of the fabric on all four sides, pinning it in place.
Sew the bias tape to the fabric along the inside edge.
Add the width and the height of the air conditioner, then multiply by two. For example, if the width is 20 inches and the height is 15 inches, you'll end up with 70 inches. Cut a length of elastic 3/4 the length of this measurement. Round down to the nearest whole number. For example, if the measurement is 70 inches, cut the elastic to 52 inches.
Pin the elastic to the bias tape on all four sides of the fabric. Stretch, space out, then pin the elastic evenly along the four sides, so that it doesn't bunch up and become crooked.
Adjust the stitch on your sewing machine to the zig-zag stitch and sew the elastic to the fabric.
Slide the cover over the front of the air conditioner. The elastic will snap back and hold the cover in place.