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How to Measure a Window for Replacement


By Carrie Dixon, Blog Editor

Measuring windows on a home for replacementIf you are interested in replacing your current windows with new ones, it is essential to be sure the windows you purchase will fit properly where the previous windows were. Measuring for a replacement window may seem like a bit of a daunting task, but it’s probably simpler than you think.

In fact, all you need to do the measuring is a tape measure, somewhere to jot down measurements, and a little bit of time.

Measuring Width

When measuring the width of the window that you require, use your tape measure to measure between the vertical jambs that form the frame of the window. You will need to measure at the top, again in the middle, and then at the bottom of the opening. If your window has liners, make sure that you remove those before proceeding with the measuring process.

Also worth noting, make certain you measure from the surface of the jambs, not from the trim or stops in the opening. Once you have your three measurements, you will use the smallest of them to determine what your width is when you order the new windows.

Measuring Height

For the height measurements, you will use your tape measure to measure from the high point of the windowsill up to the top of the window opening. Again, you must remove any range jamb liners before doing the measuring, as it will skew your results. As with width measurements, height should be taken in three places. For height make sure to measure the left side, center, and right side of the window.

You will again use the smallest measurement to determine what height of window you should choose for your replacement glass.

Measuring Depth

Measuring depth is a bit easier and only requires that you measure the depth from the inside trim to the outer stop strip. This will give you the final needed measurement for your new window.

Second Opinion

If you are worried that your measurements are off, take the time to find a second opinion. Have someone else do the measurements and see if your measurements are the same. If so, you’ve completed the process. If not, you may need to re-measure to determine what size is appropriate.

Tips and Tricks

  • Take measurements from inside the home for the best accuracy.
  • Ensure you take your time and get accurate readings, so the window fits and is efficient.
  • If you measure only to the sash stops and trim of the windowsill, your new window will be too small. Watch out for this.
  • Be sure to measure your windows before purchasing new windows. Once you’ve ordered new windows, do not remove the old windows until the replacements arrive.
  • The actual process of replacing a window will likely take less than an hour, except in specialized situations.
  • If you want to have the most accurate measurements, consider using a slide rule with extension.

Choosing Replacement Windows

There are numerous things to consider once you have your measurements. With glass alone, there are various types. For instance, double-pane windows have an air space between the glass layers that help to reduce heat loss. There are also various insulation options, and your needs may vary based on location and climate. You will also want to consider other materials, energy efficiency, and style, which is up to personal taste.

At this point, you will have the measurements you need to choose and order a new window or set of windows. Make sure you find a window that truly appeals as replacing windows is not something that most people do on a regular basis. If measuring your windows for replacement still sounds like too much to tackle on your own, contact a Five Star Rated window replacement contractor!