How to Measure a Window for Replacement

Older windows tend to be less energy-efficient, which can lead to higher energy bills and decreased home value. If you find yourself in a historic or older home with inefficient windows, the solution is clear: replace them with newer, more efficient windows. But here’s the catch – you’ll need exact measuring for replacement windows.

Whether you’re dealing with old wood windows, considering a full-frame replacement, or opting for inserts, our team at Apex Window Werks is here to guide you through the process with precision and care. So, grab your measuring tape, and let’s embark on this journey to measure your tailor-made replacement windows to ensure efficiency, style, and a perfect fit for your home.

What Are the Different Parts of the Window Called?

Before you dive into the measuring process, take a moment to familiarize yourself with the various parts of a window. This knowledge will help you understand the terminology used in the following steps.

• Frame: The window frame encompasses and provides support to the entire window system, comprising the head, jamb, and sill.
• Window sash: The movable window component that holds the glass, facilitating opening and closing.
• Window jamb: The primary vertical segments form the sides of the frame, contributing to its structural integrity.
• Window screens: Protective mesh or material fitted over windows to keep insects out while allowing air and light to pass through.
• Balance: Spring-loaded, mechanical devices frequently found in single- and double-hung windows, aiding in counterbalancing the weight of the sash during operation.
• Head: The central horizontal section at the top of the window frame.
• Jamb liner: A strip on each window side that helps secure the window sash.
• Lift: The handle used for raising the lower sash.
• Rails: For double-hung windows, three rails exist. The upper and lower rails make up the horizontal portions of the window sash, while the middle rail, or check rail, is where the lower part of the upper sash meets the upper part of the lower sash.
• Sill: The central horizontal portion at the bottom of the frame.

How to Measure Windows for Replacement

In this step-by-step guide, we’ll walk you through the process, from measuring the width and height to determining the depth of your window openings.

Step 1: Measure Window Width

If you’re getting precise replacement window measurements, it all starts with measuring the width. This crucial step involves measuring between the window jambs, those vertical pieces that form the sturdy frame of your window. Take measurements at three distinct points: the top, the middle, and the bottom of the window opening. Make sure that you measure from the surface of the jambs, not accounting for trim strips or parting beads from the existing window opening. To guarantee accuracy, always select the smallest of these three measurements when ordering your replacement window.

Step 2: Measure Window Height

Moving on to the height of your replacement window, start by measuring from the high point of the windowsill — the surface closest to the inside of the window — to the top of the window opening. This measurement should be taken at three locations: the left side, the center, and the right side of the window. Just like with width, opt for the smallest of these three height measurements when placing your order. Remember to remove any range jamb liners if your existing window has them to make sure that you measure the inside height of the frame accurately.

Step 3: Measure Window Depth

The final dimension to consider is the depth of the window opening, a critical factor for a seamless replacement. Measure between the inside window trim and the outside blind stop strip — a rectangular molding that separates the window frame’s outer trim from the sash. To accommodate the replacement window frames effectively, there must be a minimum of 3 1/4 inches of opening depth between these two points. As you start taking this measurement, disregard any pulleys or parting strips present, as they will be removed during the installation process. Accurate measurement of window depth guarantees a perfect fit for your replacement window that improves both efficiency and aesthetics.

Measuring for Various Window Types

To guarantee precision, follow the specific measuring instructions:

How to Measure Awning or Casement Windows

Measure the width of your awning or casement window at the center, extending your tape measure horizontally from trim to trim. Measure the height of your casement or awning window, extending your tape measure vertically from trim to trim.

How to Measure Single- or Double-Hung Windows

Measure the width of your single- or double-hung window from trim to trim in the middle. For sliding windows, measure from trim to trim at the center. Measure the height of your single- or double-hung window. For a sliding window, measure the height in the middle, extending your tape measure vertically from trim to trim.

How to Measure Bay or Bow Windows

Measure the width of each window panel in the bay or bow window at the center. Note the width of the center window separately, as it may differ from the others. Extend your tape measure horizontally from jamb to jamb or trim to trim. Measure the height of your bay or bow window at the center, extending your tape measure vertically from trim to trim.

Tips to Avoid Common Measurement Errors

Even with the best intentions, it’s easy to make mistakes when measuring windows. These errors can lead to frustration, delays, and potentially expensive rework. Here are some common measurement errors to watch out for and how to avoid them:

1. Not Measuring from the Jambs

• Error: Measuring from the trim or exterior casing instead of the window jambs.
• Solution: Always measure between the jambs, the vertical pieces that form the window frame. Ignore any trim or decorative elements.

2. Neglecting Depth Measurement

• Error: Forgetting to measure the depth of the window opening, which is crucial for fitting the replacement window frame.
  
• Solution: Measure from the inside window trim to the outside blind stop strip. Ensure a minimum of 3 1/4 inches of depth for a seamless fit.

3. Using Only One Measurement

• Error: Taking only one measurement for width or height instead of multiple measurements at different points.
• Solution: Always measure width and height at three points: top, middle, and bottom for width; left, center, and right for height. Use the smallest measurement for each dimension when ordering.

4. Not Accounting for Existing Window Parts

• Error: Failing to remove range jamb liners or parting strips before measuring the height or depth.
  
• Solution: Remove any existing window parts that will be removed during the installation process to ensure accurate measurements for the replacement window.

5. Ignoring Irregular Shapes

• Error: Measuring a bay window or bow window as if it were a single, rectangular window.
• Solution: Carefully measure each panel of a bay or bow window, ensuring you account for the unique angles and shapes.

It might seem like a good idea to measure your windows yourself to save some money, but mistakes can end up costing you a lot more in the long run. By following these tips and taking your time, you can minimize the risk of errors. But if you want to avoid any headaches, it’s worth considering hiring a professional to measure your windows.

Ready to Install Replacement Windows?

Apex Window Werks is a window and door repair company, serving Illinois, Wisconsin, Minnesota, and Ohio, we specialize in the replacement and restoration of windows. Our experienced team is equipped to handle every aspect of your window project, from measuring windows accurately to delivering a successful installation.

Don’t let measurement mishaps undermine your window upgrade. Contact Apex Window Werks today for a consultation and assessment, and let us help you achieve the perfect fit for your new construction window. Your home’s transformation is just a call away!

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