How to Replace Windows

You love the windows on your house, but one day you notice they're no longer in top shape and it's time to replace them. Before paying a contractor, consider installing them yourself. It's easy if you follow these guidelines.

Out with the old

Replace Windows
  1. Assess your current windows. Look for condensation inside the glass. See if they open and shut easily. Light passing through may signal a broken seal. If noise is a concern a more noise-reducing product may be needed.
  2. Decide on a frame. Vinyl is the cheapest, is maintenance-free and comes in light colors. Wood is high maintenance but can be stained or painted any color. Fiberglass/composite costs more but has better durability, is maintenance-free and takes any color paint. Aluminum is the highest priced, is maintenance-free and can be painted.
  3. Take measurements. Measure from the inside jamb of the right side to the inside jamb on the left. Due to warping, the bottom, middle and top also should be measured. Repeat vertically, going from the inside of the sill to the inside of the top window jamb. Left, right and middle must be measured. Go with the smallest measurement.
  4. Remove the stops. The stops are the thin, vertical pieces of wood that hold the sashes in place. Take them out with the help of a pry bar, screwdriver and utility knife and avoid damaging nearby materials. Keep the stops for future use.
  5. Clip the sash cords. The sash is the window's moving part. The inside sash is taken out first. Clip any cords or chains. Leave the weights, allowing them to fall into their pockets. Any exposed rope should be trimmed. Next remove the outside sash by sliding it down and taking out the parting beads (vertical strips holding sashes in place). Leave outside stops in place.

Installing Your Windows

  1. Clean the jamb. Sand wood, patch small holes and fill large ones with wood filler or putty.
  2. Prepare the new window. Check fit by placing the new window into the opening. Place the window sashes at the center. Move the bumper stops toward the middle and locate the four side mounting holes.
  3. Caulk both sides. The inside of the jamb's outside stops should be caulked. Mark, caulk and install the sill angle. Place the header on top of the window and caulk. Screw into place.
  4. Install new window. Be sure all corners are square. If necessary, tap in shims to ensure squareness. Screw in top and bottom mounting screws. Adjust the header to eliminate any space between the window and frame. Screw into place.
  5. Check that sashes slide smoothly. Adjust accordingly.
  6. Add finishing touches. Caulk inside windows and install inside stops.

Things You Will Need

  • Dripless caulking gun and caulking tubes
  • Square
  • Wood shims
  • Measuring Tape
  • Miter saw
  • Hammer
  • Cordless drill and drill bits
  • Screwdriver
  • Wood chisel
  • Utility knife
  • Putty knife
  • Small prybar
  • Replacement windows


  • The smallest measurements are used so your replacement window fits within the opening.
  • Do your homework. Use the Internet to compare window prices.
  • Make sure customer service and technical support is available.

About the Author

This article was written by a professional writer, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information. To submit your questions or ideas, or to simply learn more, see our about us page: link below.