How to Measure Replacement Windows

Installation of Replacement Doors or Windows Starts with Taking Measurements

We recently made a post where we outlined for you how to measure replacement doors for your home. While measuring for replacement windows has its similarities, it’s still a different enough process to warrant its own how-to. If you need new windows for your home, for whatever reason, here’s how to measure your windows like a pro:

What You’ll Need

First things first, you’ll need measuring tape, a pen or pencil, and a piece of paper. You’ll also need to know what kind of replacement you’re getting: is it a retrofit replacement, or a new construction replacement? For example, if the pane or sash is damaged, but the frame is still in good condition and you were happy with your original window, you would get a retrofit. However, if your frame is warped or damaged due to age or other conditions, if your window is old and prone to drafts, or if you are otherwise updating it completely, you will want a new construction. When purchasing and installing your new replacement windows, it is important to know which you need.

Anatomy of Your Window

There are three main parts of your window to measure—and a fourth if you are measuring for a retrofit. Like with measuring for replacement doors, there is a jamb, which is the vertical portion of the frame that rests right up against the sash (the moving part). Along the top is the head, which frames the top of the sash, and along the bottom is the sill. The sash itself is the material that the glass pane is framed in, and makes up the moving part of your window, whether it’s a hung, sliding, casement, or awning window.

Taking the Measurements

This part may sound familiar to you if you’ve already measured replacement doors, but for the rest of you, he is how you properly measure a window. First, you should be taking these measurements from the outside of your house with the screen removed. Draw a diagram of the rough shape of the window—it doesn’t need to be precise, because that’s what the measurements are for! Take your tape measure and measure the distance from jamb to jamb at three different points along the window’s height, and record the smallest of the three numbers that you get. Repeat the same process, this time measuring from head to sill. If you’re measuring for a retrofit and your sash can easily be removed from the frame, go ahead and measure its height and width as well, using the same method as before.

Call a Professional

Once you’ve got the necessary details, or if you run into any problems along the way, call a professional right away. Just like that, you’re on your way to having great replacement windows for your hom

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