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How to Insulate Windows

Steps and Tools for Insulating Windows

Not every insulation project follows the same process. Here are a few basic techniques you'll need to know an­d tools you'll need to have handy when insulating your windows.

  • Plastic insulating film. It's easy to find inexpensive window insulation kits at hardware or home-repair stores. The kits come with a large sheet of plastic film and a quantity of double-sided adhesive tape. Stick the tape around the window frame on all four sides, then mount the film on the tape so it completely covers the window. The film will block all access to the window, so if the window has Venetian blinds, cut a little hole while mounting the film and sneak the control rod through so the blinds can be opened and closed. Cut the excess film away with a knife or scissors. The last tool needed for this job is a hair dryer: Blow hot air at the film so it tightens and makes a firm seal with no wrinkles.
  • Insulating drapes. The key to using drapes as window insulation isn't the heaviness of the material but the tightness of the seal. The objective is to prevent the room air from circulating into the space behind the curtain. Weights, magnets, Velcro, snaps or staples can be used to make sure no space is left between the drapes and the window frame, windowsill or floor. You can insert effective thermal shades while leaving existing drapes or shutters in place. Do-it-yourselfers can make them at a fraction of the retail cost.
  • Insulating at window sashes. The challenge of this job is prying off the molding that surrounds the window frame. Once that's done, it's relatively simple to measure a piece of rigid insulating foam to fit into the space between the window jamb and the wall, and spray a substance such as expanding polyurethane into the jamb itself.

In the next section, we'll find out how your hard work will pay off!