Replacing old, cracked, drafty windows with new, double-paned, energy efficient windows is a good investment in both your home and the environment.

By making the switch yourself, you can do it without breaking the bank. Lowes.com offers their step-by-step instructions for getting the job done:

First measure for new windows:
It is important to have accurate measurements for every window in your home. Accurate measurements ensure that your windows fit properly for maximum energy savings and ease of installation.

Important!

Take all measurements from inside your home.

Be sure to measure all the way to the jambs on the left and right. Measuring only to the stops would cause your new windows to be too narrow.

1. To find the width, measure from the inside of the jamb on one side of the window to the inside of the jamb on the other side of the window. Measure at the bottom, middle and top of the window. Use the narrowest measurement for the width of your replacement window.

2. To find the height, measure from the top of the sill to the bottom of the window’s head jamb. Measure at the left, middle and right of the window. Use the shortest measurement for the height of your replacement window.

Using the smallest measurements ensures that the replacement window will fit inside the existing window frame.

Remove the old window sashes:

Since the replacement windows fit inside the existing window frame, you only have to remove the sashes, parting bead and inside stop from the existing window. To make the project easier and safer, install your new windows from inside your home.

1. Remove the inside stop pieces from the window. Take care when removing these pieces; you will reuse them when installing the new windows.

2. Remove the inside sash. If the old window uses weights, cut the sash cords or chains. Let the weights fall to the bottom of their wells and simply leave them there.

3. Slide the outside sash to the bottom of the window. Remove and discard the parting beads. Remove the outside sash in the same manner as the inside sash. Do not remove the exterior stop from the window jambs. These stops will retain the replacement window when you install it.

4. Clean the window jambs and sill thoroughly. If the old window had weights, either drive the pulleys into the frame or remove them entirely. Fill any holes in the jambs or sill with caulk.

Install the new window:

Poorly installed or adjusted windows waste energy and are difficult to operate, so take your time installing and adjusting your new window.

1. Lay a bead of caulk along the inside of the outside stops on the jambs. Mark the sill for the sill angle. Caulk and install the sill angle.

2. Center the top and bottom sashes vertically in the new window frame. Slide the bumper stops toward the center of the frame until the four mounting holes in the side jambs (two top and two bottom) are visible.

3. Place the header, also called the expander, on top of the window and caulk its top.
Window expander.
Put the header in place and secure it with the small screws provided with the window.

4. Place the window in the opening and check for square. If the window is not square in the opening, shim as needed to square it. Install the mounting screws at the top and bottom of each side jamb. Do not install the screws so tightly that they deform the side jambs.

5. Slide the header up so that it seals any gap between the top of the new window and the old frame. Use the screws provided with the window to secure the header in place.

6. Slide the top and bottom sashes up and down to check for gaps and smooth operation. If the sashes do not operate smoothly, use the built-in adjustment screws in the side jambs to adjust the window frame. Precise adjustment varies by manufacturer, so refer to the manufacturer’s notes for specific adjustment instructions.

7. Caulk the inside of the window and reinstall the inside stops.

This is a do-it-yourself project for a homeowner who has had some previous experience with home remodeling projects.