Replacement Window Terminology Explained For La Crosse, WI

Window Terminology: Understanding The Lingo
Behind Your La Crosse, WI, Home’s
Replacement Windows

Sash, Pane, Double-Hung
And More – Let Us Help
You Make Sense Of
Your Windows

Congratulations! You’ve decided to install replacement windows on your La Crosse, WI home. Doing so decreases your power bills due to replacement windows being made with energy efficiency in mind while simultaneously boosting your curb appeal.

However, most homeowners can feel lost when confronted with the often confusing terminology.

Let The Board Store simplify the process. We’ve honored our commitment to providing the good people of La Crosse County with outstanding service for over 34 years, and we’re here to answer all your questions and streamline what can feel like an exciting – yet overwhelming – time.

At the end of the day, you want to be happy with your replacement windows. Let’s introduce popular terms in the replacement window industry and what they mean.

List Of Replacement Window Terminology

Don’t Let Confusion Get In The
Way Of Your New Windows

Many terms surround replacement windows – some relatively easy to understand, while others can be downright puzzling. After all, how many times have you ever used the term “low-E glass coating?”

Check out the common terms you’ll most likely hear during the window replacement on your La Crosse, WI, home.


Window glazing refers to the type of glass that is in the window. It may state the number of layers of glass in the window or could refer to additional characteristics like muntins (sometimes called grids) or decorative glass like ProVia Inspiration glass or leaded beveled glass.

In modern high-efficiency glazing, the type of spacer separating the layers of glass is often called a warm edge spacer as it is designed to be much more efficient than the aluminum spacers of years past.

Single Glazing

Single-glazed windows – also called single-pane windows – have only a single pane of glass. They are commonly seen in older homes and aren’t used in new construction because they lack insulation and are extremely energy inefficient.

Double Glazing

Double glazing simply means that there are two layers of glass in the window assembly. In older homes, the double glazing could be made up of a single-glazed window with an attached storm window.

When speaking about new windows today, double-glazed windows, also called double pane windows, are made with two panes of glass separated by a spacer and sealed to create an insulated panel and prevent moisture from entering and disrupting visibility.

In northern climates, as we have in Wisconsin and Minnesota, Insulated glass with low-E technology, warm edge spacer, and argon fill is the standard for most new construction and for replacement windows. Double-pane windows also reduce sound transmission for a quieter home.

Triple Glazing

Triple glazing – also called triple-paned – describes windows with three panes of glass. They are assembled like double glazing but with an additional spacer and layer of glass. They also typically incorporate low-E glass, warm edge spacers, and argon or krypton glass to maximize their insulating value.

Triple-glazed windows are the most energy efficient as well as providing the maximum sound reduction to ensure a warmer and quieter home in your La Crosse County home.


A sash is a moveable panel within a window (either single or double-hung) that holds one or more glass panes.

Single Hung Windows

A single-hung window is a traditional window with a bottom sash that moves up and down and an upper sash that is stationary (it won’t open).

Double Hung Windows

Double hung windows are similar in appearance to single hung windows but both the upper and lower sash open and close if the window is operating properly. Double-hung windows are the most common window in nearly all homes built before 1950 in the Midwest. When working properly, the windows can be opened at the top or bottom or both for optimum ventilation.

Older double windows can be challenging to clean, especially if they still have a storm window, and they require climbing a ladder outside the house.

Our modern double-hung replacement windows ensure your safety as they do not require storm windows and are simple to clean as they tilt in for washing. Screens are located on the exterior and a full screen ensures ease of ventilation top or bottom without worry of insects in the house.

Single Slider Windows

Sometimes called a single-hung slider, this is a window where the sash moves side to side rather than up and down like in the single-hung or double-hung. There are two sashes in the window but only one is operable. These are not as convenient but are often used when looking for the least expensive alternative.

Double Slider Windows

A double slider is a much more common window choice because both sashes slide back and forth allowing for more options for ventilation. Like double-hung windows, the older style windows present challenges when it’s time to clean the glass.

Generally an all-day job with a ladder, a helper on the inside, and an occasional cuss word. Fortunately, our replacement slider windows lift out to the inside for easy cleaning. Double sliders are very popular as sunroom windows as they provide the largest operable glass with the least obstruction to your view.

The screen is located on the exterior of the slider window, and our standard is a full screen allowing ventilation from either side without worrying about bugs getting in.

Casement Windows

Casement windows have hardware that allows the entire window sash to swing out much the same as a door operates. The hinge side can be either left or right, and these windows are often combined or mulled together with additional casements or in combination with fixed windows which are often referred to as picture windows.

Because they are usually the most energy-efficient operable window, they are a favorite in new homes in northern climates. Our casement windows are designed so that when they are opened, and the interior screen is removed, you can reach the exterior of the glass for easy cleaning without ladders and risking a fall.

These windows open on hinges similar to a door. They aren’t as common in newer homes, but they add a unique charm to any house.

Bay Windows

Bay windows project from the exterior of the home, providing an expanded view from the inside and the feeling of added space in the room. The bay window is typically made up of three windows, with the two side windows being operable double-hung or casement windows and the center window a fixed or picture window.

The depth of the bay window is determined by the size and angle of the flankers (usually 30 or 45 degrees). Properly installed bay windows have a well-insulated seat and headboard. When installed in a one-story home, the overhang of the home becomes the roof of the bay window.

If there is no overhang, a roof is constructed to cover and protect your beautiful new bay window.

Our replacement bay window is manufactured to fit precisely where an old window is removed. In fact, an old slider window or set of double hugs with a picture window can be replaced with a bay window with virtually no disruption to the home. This is a great way to give the exterior and interior of the home a great new look with no major construction required.

Bow Windows

Bow windows share all of the characteristics and advantages mentioned about bay windows but are usually installed when a larger projecting window is desired. They present a gentler curved appearance rather than the bolder angle of the bay window.

They are constructed with a combination of four, five, or six operable casements and fixed windows. They are an elegant addition to any home, offering a panoramic view of the outdoors and a feeling of a larger space in any room.

Picture Windows

Fixed frame windows, commonly called picture windows or stationary windows, are windows that do not open. These windows are generally used in combination with operable windows like double hung or casements to create a larger assembly that expands the view and opens the home to the beauty of the outdoors.


Weatherstripping is a material attached to the window sashes to close the space between the sash and the frame of an operable window. The big job of weatherstripping is to restrict the airflow or air infiltration through the window to ensure comfort and energy efficiency.

In simple terms, it is incorporated into the window design to prevent the drafts common in older or failing windows. Our windows are designed with multiple layers of weatherstripping for maximum efficiency and comfort. The weatherstripping also gives added protection against water penetration when rain and wind come together.

Low-E Glass Coating

Low-E glass is a window glass that has multiple layers of material applied to the glass to increase the efficiency of the glass when used in a double or triple-glazed assembly. Low-E is an abbreviation for “low emissivity,” which means it reduces the amount of heat that a piece of glass emits or radiates through the glass.

Stated in layman’s terms, it means there is not as much heat or cold penetration through the glass. In addition, the low-E glass reflects both UV rays and solar radiation. Reducing UV rays protects the furnishings in your home from fading and deterioration. Reflecting solar heat gain, low-E glass reduces air conditioning costs and contributes to your comfort on hot summer days. Overall, the low-E coatings on dual and triple pane glazing significantly improve their insulating value.

Energy Efficiency

This popular term has become a buzzword in recent years regarding replacement windows and doors. Why? Older windows had the nasty habit of wasting energy and creating discomfort because of poor insulating quality and excessive drafts. Energy efficiency describes how well your windows conserve energy.

Energy-efficient windows help decrease your home’s power bills while boosting your property value and curb appeal. The good news for homeowners is that all quality replacement windows are rated under a common standard created by NFRC (National Fenestration Rating Council) and utilized for the Energy Star Program.

By comparing the ratings for windows, as published and available from each manufacturer, you can make an accurate comparison of the ratings of various products.

Of course, proper installation of any window is also a significant factor in how well the window will perform in your home. So, choosing a company of experienced qualified installers is an important aspect of any window replacement project.

Condensation Resistance

This term refers to how resistant your replacement windows are to the buildup of moisture on the interior surface of the glass in your windows.

Air Leakage

Air leakage, or air infiltration as it is commonly called, refers to the amount of air that comes in through or escapes out through a window assembly. There is always a space between the operating sash of a window and the frame.

Energy-efficient windows are designed to fit tightly and include multiple layers of weatherstripping to control air movement through the window. Excessive air leakage through older inefficient windows creates drafts and discomfort as well as putting an added load on your HVAC system and can increase your energy bills.

Here at The Board Store, our top-tier windows come equipped with state-of-the-art seals and weatherstripping to prevent air leakage from around your windows.

Visible Transmittance

Also referred to as VT, visible transmittance is simply how much sunlight a window filters into your home. Windows with a high VT score allow more light inside the home as opposed to windows with a low VT.


A window’s U-factor is a rating based on your window’s resistance to heat or thermal resistance. A window with a low U-rating will be a better insulator than windows with a high U-factor. Energy Star ratings required for new windows provide a reliable and unbiased comparison of windows from various manufacturers.

Solar Heat Gain Coefficient

Also commonly abbreviated as SHGC, a window’s solar heat gain coefficient represents the solar heat the house absorbs. This number is used to rate windows and is a decimal between 0.0 and 1.0.

The higher the SHGC, the more solar heat your home absorbs – northern homeowners can balance the advantage of the heat gain in winter months with the added cost of air conditioning in the summer months.

The Board Store: La Crosse, WI’s One-Stop Shop
For Top-Tier Replacement Windows

The Board Store is a full-service home renovation shop with strong, lasting community ties. With more than 34 years of experience under our belts, we’re here for you and your home every step of the way.

If you’re ready to replace your old windows in La Crosse, WI, and give your home a whole new look, contact us online for a free estimate today.

Share this article