Measure For Replacement Windows | Window World

How to Measure for Replacement Windows

When it comes to replacing a window in your home, the measurement of the window is arguably one of the most important steps. Proper measurements ensure a good window fit which means you get the most energy efficiency and best aesthetics possible. Even a slight mis-measure can mean the window is too big or too small to fit the opening. In this article, we’ll give you instructions for measuring for a replacement, retrofit window. But before we get started we want to make sure that you, our reader, understands that these are simplified instructions to give you an idea of how to measure a window. If you are looking at replacing windows in your home and are new to measuring windows, do not use this as your guide. We strongly encourage you to have a professional measure your windows to ensure proper measurements are taken so you will not need to reorder any windows due to incorrect measurements.

Step 1: Measure Horizontal Width

When measuring the width of the window you’d like to replace, the best way to measure your window’s width is the measure at three points. A seasoned installer is usually able to eyeball when a window is not perfect, equal distances or parallel. But if you’re new to measuring and installing windows, you’ll want to be sure to measure at all three points to ensure you use the right measurement when ordering. You may need to move the window sash to get proper measurements.

Take 3 Window Measurements

You are going to measure between the jambs at the top-most width, the middle, and the bottom. Measure from the surface of the jamb, not the trim strips in the old window opening. Once you have your three measurements, you’ll use the smallest measurement for your width. For example, is your measurements were:

Top - 61.5

Middle - 61.5

Bottom - 61.25

You’ll use the bottom measurement as your width measurement.

Subtract X

You may have heard that you’ll need to subtract something to get your “final measurement” for ordering. Don’t do this. When ordering your windows, provide the opening size only. The manufacturer will deduct 1⁄4 inch from the width and will cut the window to the nearest ⅛ inch increment.

Step 2: Measure Height (Vertically)

When measuring the height of your window, the number of points you need to measure will depend on the height of your window. You should definitely measure at least two points. If it is a taller window, you’ll want to measure at least three points. And if you had three different measurements when measuring the three points for the width, then we strongly suggest taking all three measurements for the height, no matter how tall it is. It’s very possible your window opening was originally cut imperfectly and is not perfectly parallel. This is important to know when ordering and then later when installing your windows.

Take 3 Measurements

Take a measurement of the height from the far left of your window, the middle, and the far right. Start your measurement from the surface of the jamb, not the trim strip. Just like with the width measurement, you’ll want to use the smallest measurement for the height when placing your order.

Subtract X

Again, like with the width measurement, provide only the opening size measurement. The manufacturer will deduct the ¼ inch and then build the window to the closest ⅛ inch.

Step 3: Measure Window Depth

When measuring the depth, be sure to ignore all pulleys and parting strips; they’ll be removed when the window is installed and shouldn’t be factored into the measurement. Also note that there needs to be at least 3 ¼ inches of opening depth between the inside window trim and the outside blind stop strip. To measure, run your tape measure from edge to edge. You’ll want to measure the depth like this in several points around all 4 sides of the frame.

Tip: If you can’t open your window, measure the depth on each side of the glass and add them together. Then add the thickness of your window glass pane. A single window glass pane is usually ⅛ inch or 3 millimeters in thickness.

What is the Standard Size of a Window?

If you are looking for standard window sizes, stop looking. There is not one particular standard dimension upon which you can base your window sizes. There are however, standard sizes based on the manufacturer’s specific windows. This being said, your best option is to check out the measurement of the opening where you will be installing the window and then try to look for manufacturers who may have the size that you need. If you’re able to order a standard size, it may help cut down on the manufacturing time.

If the manufacturer doesn’t have anything standard for you, you will have to have your window custom-sized for a good fit.

Common Types of Replacement Windows

You may have originally had a single-hung window but would prefer a double hung window. Or you don’t require the extra ventilation so a picture window would be a good replacement option. When updating your windows, the fun part is that you can mix up the type of window you’re replacing. So what are some common types of replacement window and why are they popular?

Double Hung Window

Double hung windows are the single most common window on the market. They are commonly used due to the increased airflow and ventilation they provide and their tilting sashes make cleaning even a second story window a breeze. Use the instructions provided here to measure for a double hung replacement window.

Sliding Window

Sliding windows are available in either 2 or 3 panel configurations and feature either one or two movable panes. A great spot for a sliding window would be anywhere you have a panoramic view since these windows are horizontally oriented. Use the instructions provided here to measure for a replacement sliding window.

Awning Window

Awning windows operate by crank and open from the bottom with the top edge fixed in place. Awning windows are frequently used as a low level window (easily accessible from the ground outside your home) where intruders might be a problem. They’re also great when it rains since they can be left open with the glass acting as an “awning” that prevents water from getting inside.

Picture Window

Picture windows are perfect for spots where you want extra light but don’t need the extra ventilation. They provide an unobstructed view with little to no maintenance required. Picture windows can also come in specialty shapes to give your room or home a unique look. When it comes to measuring, if you’re wanting to order a standard square or rectangular picture window then you can use the instructions provided here. However, if you’re in the market for a specialty shape, we strongly encourage you to have the space measured by a professional.

Types of Energy Efficient Glass

When replacing your windows, you not only have the opportunity to change the style of window, you also have the opportunity to upgrade the energy efficiency of the glass. Depending on who you purchase your replacement windows from and in what state you are located, there may be minimum requirements for the energy efficiency and number of panes the window is required to have. For instance, in Las Vegas, Nevada, the windows must be Energy STAR certified and be double pane due to the intense heat and sun. When ordering your windows, be sure to ask about any requirements you may need to be aware of.

Low-E Glass Panels

SolarZone Low-E Glass is designed to block heat from the sun’s rays in the summer but allows warmth from shorter solar rays into the house during the cold winter months. By blocking the sun’s rays, you’re not only making your home more energy efficient, you’re also cutting back on some of the wear and tear on your floors and furniture that comes from the intense and hot sun.

What is Argon Glass

Argon glass is used as a great insulation system for replacement windows. The space between the glass lites, historically just dead air, is filled with Argon gas. This colorless, odorless, non-reactive gas is the third most prevalent gas in our atmosphere. Its extremely low thermal conductivity and high density (Argon is 38% denser than air) makes it an ideal insulating agent.

Window World Glass Packages

The SolarZone Sunshield (blue color) has a .14-.15 SHGC and is an extra $100 per window. We also have the Laminated Glass package that provides greater noise reduction and is break-in deterrent for $150 per window.

The Acoustic Glass package (AKA offset glass package) also provides greater noise reduction for $100 per window. Which package you choose should depend on your home, where it is located, where the sun hits your home, and the amount of noise pollution near your home.

Summary

When you’re measuring to replace a window, always remember the three measurements for the width and height. For the depth, be sure to measure the depth on all four sides. Always use the smallest measurement and don’t subtract anything. When it comes to ordering, local window companies and home improvement stores don’t readily have a lot of window sizes available for purchase. So you’ll most likely have to wait several weeks for a manufacturer to make your windows specifically for your home.

When ordering your new window, also remember you can replace your current window with a different style. If you’d like more ventilation, you may opt for a double hung window. If you want less ventilation and more view, you may decide to replace with a picture window. Customizing the window for your space helps to create a personal and unique touch to your home. Don’t forget about the energy efficient glass available and any glass package upgrades. You’re wallet will thank you later.

And always remember, Window World is here to provide free in-home estimates to replace your windows and we do all the measuring for you. So if there’s an accidental mismeasure, we take the window and order you the right size without any hassle to you or your wallet. Call us today at 702-897-8209 to schedule your free in-home estimate. Our professionals are here for you now with a free consultation virtually or in your home.