If you’ve been searching “how to measure a window for replacement,” chances are you’re getting ready for an exciting home upgrade. Whether you’re replacing old, drafty windows or upgrading to energy-efficient models, getting accurate measurements is the most crucial step. At Perfect Windows and Siding in Des Plaines, IL, we help homeowners from Park Ridge, Mount Prospect, and surrounding areas navigate window replacement with precision and confidence.
In this comprehensive guide, we’ll walk you through:
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The tools you’ll need
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Step-by-step measuring instructions
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Tips for different window types
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Common measurement mistakes
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How we compare to local competitors
Let’s make sure your replacement windows fit perfectly—just like our name.
Why Correct Window Measurements Matter
A window that’s even slightly too big or small can lead to air leaks, water damage, and costly adjustments during installation. Whether you’re doing it yourself or hiring a contractor, taking accurate measurements ensures:
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A proper, weather-tight fit
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Efficient energy performance
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Easy ordering and installation
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Cost savings on labor and materials
When homeowners in Des Plaines search for “how to measure windows for replacement near me,” they often end up with incomplete or confusing instructions. That’s where we come in.
Tools You’ll Need
Before you start, gather these basic tools:
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Tape measure (preferably steel and at least 25 ft long)
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Notebook or phone for recording measurements
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Ladder or step stool (for tall windows)
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Pencil or marker
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Camera or phone (optional, for photos of window styles)
Pro tip: Always measure in inches, and round down to the nearest 1/8 inch to avoid ordering a window that’s too large.
Step-by-Step Guide: How to Measure a Window for Replacement
You’ll be taking three key measurements: width, height, and depth.
1. Measure the Width
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Step 1: Open the window and measure from jamb to jamb (side to side) in three places: top, middle, and bottom.
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Step 2: Write down all three numbers.
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Step 3: Use the smallest of the three as your actual width measurement.
This ensures the replacement window will fit the narrowest point of the frame.
2. Measure the Height
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Step 1: Measure from the head jamb (top) to the sill (bottom) in three places: left, center, and right.
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Step 2: Again, record all three and use the smallest number.
Important: Measure to the high point of the sill (not the trim or stool), as this is where the window will rest.
3. Measure the Depth
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Step 1: Measure from the inside trim to the outside stop (not including the part of the frame sticking out).
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Step 2: Most replacement windows require a minimum depth of 3¼ inches.
Depth is important if you’re considering full-frame replacements vs. insert replacements.
Extra Tips for Specific Window Styles
Different window types require unique considerations:
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Double-hung and single-hung windows: Always confirm that the sash area isn’t warped or bowed.
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Casement windows: Measure from inside the frame and note the hinge side.
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Bay or bow windows: These require professional measurement due to custom angles and projection.
If you’re unsure, Perfect Windows and Siding offers free in-home measurements for residents in Des Plaines and nearby suburbs.
Common Window Measuring Mistakes (and How to Avoid Them)
✅ Mistake: Measuring from the trim.
Always measure from jamb to jamb, not from decorative elements.
✅ Mistake: Using just one measurement.
Window frames can be uneven, so always take three measurements for width and height.
✅ Mistake: Rounding up.
Never round up. A too-large window won’t fit and may need resizing at your expense.
✅ Mistake: Forgetting to note window type or style.
This helps you choose the right replacement frame and installation method.
How We Compare to Local Competitors in Des Plaines, Park Ridge & Mount Prospect
When searching for “window measurement and replacement Des Plaines IL,” you’ll find several companies. Here’s how Perfect Windows and Siding stands out:
1. Renewal by Andersen – Mount Prospect
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Pros: National brand, known for durable materials.
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Cons: Expensive, longer lead times, limited flexibility with custom sizes.
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How We Compare: We offer more affordable options with personalized service, and we’re local!
2. Next Door & Window – Park Ridge
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Pros: Wide product range, good reputation.
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Cons: Requires multiple appointments for quoting and measuring.
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How We Compare: Our free consultations include expert measurements and clear pricing on the spot.
3. Window World of Chicagoland
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Pros: Budget-friendly.
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Cons: Less customization, mostly vinyl options.
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How We Compare: We offer vinyl, wood-clad, and composite windows with custom sizing and a focus on quality—not just price.
Why Des Plaines Homeowners Trust Perfect Windows and Siding
We’re not just window installers—we’re window experts. Here’s what you get when you work with us:
✔️ Accurate, in-home window measurements
✔️ Custom-fit energy-efficient windows
✔️ Expert installation backed by warranty
✔️ Honest, no-pressure pricing
✔️ Locally owned and operated in Des Plaines, IL
Our team knows the housing styles and building codes across Mount Prospect, Park Ridge, and the broader Chicagoland area. That means we get it right the first time.
FAQ – Measuring for Window Replacement
Q: Can I measure my windows myself?
Yes! This guide is designed to help you do just that. But for complex installations or unusual window shapes, professional help is recommended.
Q: How accurate do measurements need to be?
Very. Even a 1/4 inch off can result in a poor fit. Always triple-check your numbers.
Q: What if I have older windows with rot or damage?
That may require full-frame replacement, which includes replacing the frame and not just the sash. We’ll inspect during your free consultation.
Q: What’s the average window depth?
Standard replacement windows usually fit a depth of 3¼ inches, but some older homes may differ.
Ready to Replace Your Windows? Let’s Get Started
Stop wondering “how do I measure a window for replacement near me” and let the professionals handle it. At Perfect Windows and Siding, we offer:
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Free in-home measurements
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Expert product recommendations
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Fast, clean installation
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Financing options and energy rebates
📍 Located in Des Plaines, IL, we proudly serve:
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Park Ridge
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Mount Prospect
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Arlington Heights
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Niles
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Elk Grove Village
🪟 Call us at (847) 999-7840 or schedule a free estimate on perfectwindowsandsiding.com
Final Thoughts
Measuring windows for replacement doesn’t have to be stressful. With the right tools, steps, and professional support, you can be confident that your new windows will fit perfectly and perform beautifully. Whether you’re replacing one window or your entire home, Perfect Windows and Siding is here to help every step of the way.
