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How to Replace Old Windows

Replacement windows can be found in all sizes, shapes, models, and types. Most of them are manufactured of lightweight materials (even the wooden ones), making it easy for you to “shed new light” on your old home.

Things You'll Need

  • Measuring tape, paper, pencil/pen
  • Replacement windows and mounting hardware
  • Hammer or hand-held or electric screwdriver
  • Caulk
  • Paint (if necessary for “touching up”)
  • Framing square (to make sure the window is straight and even on all sides)
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Instructions

  1. How to Replace Old Windows

    • 1

      CAREFULLY measure the height and width of EACH and EVERY window frame that will have a replacement window installed. Record your measurements on a piece of paper. The more careful you are with your measurements, the less chance there will be that you will have to enlarge openings or make allowances for windows that are too small to fit existing openings. (See TIPS section for more information.)

    • 2

      Purchase your replacement windows. If you order your windows, make sure the measurements are given precisely and accurately. If you physically purchase your own replacement windows, make sure the ones you buy exactly match your measurements.

    • 3

      Once you have the new replacement windows in your home, then, AND ONLY THEN, remove the old windows. You may wish to remove only one window at a time, unless you know that inclement weather is not going to be a factor before the job is completed.

    • 4

      Make any repairs that might be necessary to the frame and/or wall surrounding where the old window once was, such as smoothing rough places, removing old paint or caulking, or re-painting if removal exposed old paint or damaged existing paint. Allow any paint to dry thoroughly before proceeding.

    • 5

      Locate the replacement window that is meant to be installed in the frame where you are currently working. Fit it into the frame, and make sure that it fits exactly as it should. Do not fasten or secure it at this time. If you are satisfied with the fit, remove the window, and proceed. If not, make the necessary repairs or adjustments to make the window fit properly. (See TIPS section for more information.)

    • 6

      Apply caulking to the windowsills and sides of the window frame. This will help secure the new window, and will provide additional protection against leaks and drafts.

    • 7

      Fit the window back into the opening. Use your framing square to make sure it is square and even. Use small pieces of wood (called “shims”) to help you adjust the window to where it fits properly on all sides.

    • 8

      Following manufacturer’s instructions, securely fasten the window to the frame.

    • 9

      Once it has been fastened, check to see that the window opens and closes properly. You may be able to remove any “shims” that were needed, or you may have to leave some, or have to add some. Do whatever is necessary to assure that the window works as it should.

    • 10

      Repeat each step as needed until all new replacement windows have been installed.