How to Switch Out a Large Window With a Smaller Window

Replacing a window in a house is normally done by measuring the width and height of the opening to get dimensions. However, sometimes you might want to use a smaller window instead. A smaller window will require additional framing to accommodate the new size. A few key steps should ensure a good fit.

Step 1 Decide on the new window's size. Use a tape measure to get accurate dimensions of the existing window opening and determine how big the new window needs to be.

Step 2 Buy a replacement window from a home-improvement store.

Step 3 Remove the old window. Check how the window originally was installed to decide what tools you will need to take it out. For example, a window might be installed with screws or with nails that could require cutting.

Step 4 Unscrew or cut away the supports for the window. Use a reciprocating saw to cut any nails that can't be removed easily. Install a blade into the saw by pulling up on the clamp release lever and inserting the blade. Push the clamp release lever down to lock the blade in place and then plug it into an outlet to begin cutting.

Step 5 Pull the window out of the opening and remove all debris, such as nails, from around the window opening

Step 6 Measure and cut pieces of 2-by-4 board to build a new window opening. Use a tape measure to find the correct space from each side of the opening to place the cut pieces.

Step 7 Insert and nail the cut pieces into the opening to use as a new support for the window frame. These are going to act as new studs in the wall; they will be used to attach the window.

Step 8 Insert the new window into the opening and secure it to the new frame. Depending on the the size of the window, use two to three screws on each side of the window.

Step 9 Use a bottle of foam insulation to fill in around gaps between the window and the frame.

Step 10 Install new insulation and drywall around the window.