How to Measure Window Frames

Accurate measurements make replacing windows easier.

Homeowners replace windows for a variety of reasons. Some windows break due to accidents, falling trees or hail damage. Many homeowners replace old single-pane windows with newer energy-efficient double-pane windows to save money on heating and cooling. Accurate measurements of the window opening allow easier installation of a new window, with little extra framing or adjustments needed to the opening.

Things You'll Need

• Measuring tape

Instructions

Aluminum and Metal Frames

1. Remove the window screen from outside the house. Grasp each of the two pulls at the top of the screen frame that are a "U" shape. Pull the top of the screen outward at a 45-degree angle while pushing it down into the window frame channel. Set the screen aside.

2. Open the window to have a full view of the opening size.

3. Determine which of the three window flanges protrude most into the window opening. Generally, it is the middle flange, but this varies by brand. Use a measuring tape to measure from this flange to the flange directly across from it.

4. Measure the width at the middle of the window from the left to right flange. Measure the top and the bottom flanges in the same manner. Write down all three measurements.

5. Measure the height in the same manner, on the left, right and middle points of the window from the top of the header to the windowsill. Write down all three measurements.

6. Order a new window using the smallest width and height measurements.

Wood Frames

1. Remove the screen from the window on the outside of the house. Grasp the left screen pull with the left hand and the right pull with the right hand. Pull outward at a 45-degree angle while pushing the entire screen down into the window frame channel. Set the screen aside.

2. Open the window.

3. Measure the width of the window inside the frame from the left jamb to the right jamb. Take measurements at the top, middle and bottom. Record all measurements on paper.

4. Measure the height of the window inside the frame from the flat part of the windowsill to the window header at the top of the framework. Take measurements at the left, center and right. Record all measurements on paper.

5. Order a new window using the smallest measurement in height and width, minus 1/4 inch on each measurement.

Tips & Warnings

• Subtracting 1/4 inch from the width and height of a wood frame allows for the new window and gives a 1/4-inch variance for adjustments due to the wood swelling from weather conditions.

• Replacing a window with a larger window necessitates tearing out and rebuilding the framework in the wall.

• Buying a replacement window that is slightly smaller than the original version requires a few wood shims to fit it into the opening.

References

• 1st Windows: How To Measure For Your New Windows