Tempered Glass Replacement Windows: When & Where Do You Need Them?

When replacing windows, most homeowners focus on frame materials, energy efficiency, window styles, and cost. The type of glass inside the window deserves just as much attention. In some areas of a home, standard window glass may not be the right choice. You may need tempered safety glass instead. Tempered glass is designed to reduce the risk of serious injury if a window breaks. Building codes commonly require safety glazing in locations where someone is more likely to fall into or come into contact with the glass.

If you’re planning to replace windows in your Nebraska home, it helps to understand what tempered glass is, where it may be required, and how it fits into an energy-efficient replacement window.

What Is Tempered Glass?

Tempered glass is a type of safety glass that goes through a controlled heating and cooling process during manufacturing. This process changes the internal stresses in the glass and makes it stronger than standard annealed glass. The biggest difference becomes apparent when the glass breaks.

What Happens When Tempered Glass Breaks?

Standard window glass breaks into large, sharp pieces. Tempered glass is designed to break into many smaller pieces. This reduces the risk of the large, dangerous shards associated with broken standard glass. That’s why tempered glass is commonly used in locations where accidental contact with a window is more likely. Tempering doesn’t make a window unbreakable. A strong enough impact will still break the pane. The difference is primarily in how the glass behaves when it breaks.

How Can You Tell If Window Glass Is Tempered?

Tempered glass usually has a permanent manufacturer’s marking, sometimes called a bug or safety glazing mark, near one corner of the pane. The marking includes information about the manufacturer and applicable safety standards. These markings are small and difficult to see, especially on older windows. If you’re unsure what type of glass you currently have, a window professional can inspect the window and determine what type of replacement glass is appropriate.

Tempered Glass vs. Regular Window Glass

Both tempered and standard annealed glass are used in residential windows, but they serve different purposes.

Tempered glass isn’t automatically necessary throughout an entire house. Its use generally depends on the window’s size, placement, and proximity to areas where accidental human impact is more likely.

Where Is Tempered Glass Required in Replacement Windows?

Building codes establish requirements for safety glazing in certain locations. The exact requirements that apply to your project depend on the current code and local jurisdiction. That’s an important consideration when replacing older windows. An existing window may have been installed decades ago under different requirements. Replacing that window brings the new installation into compliance with current requirements for the project. Several locations commonly warrant closer attention.

Windows Near Doors

Windows located close to doors present a higher risk because people regularly move through the area. Someone opening, closing, or walking through a doorway could accidentally make contact with nearby glass. This applies to sidelights and certain windows positioned close to swinging or sliding doors. Whether a specific window requires safety glazing depends on its exact dimensions and location, so evaluate the opening before ordering the replacement window.

Windows Near the Floor

Large panes of glass located close to a walking surface also present a safety concern. A person who trips or falls may come into direct contact with the glass. Safety glazing requirements apply when a window meets certain conditions related to the size and position of the glass. This is particularly relevant for large windows that extend close to the floor.

Bathroom Windows

Bathrooms are another area where tempered glass may be required. Windows around bathtubs, showers, and similar areas carry a higher risk because wet surfaces make slips and falls more likely. Keep in mind that privacy and safety are separate considerations. Frosted or obscure glass can provide privacy, but that doesn’t automatically make the pane safety glass. A bathroom window should be both tempered and manufactured with privacy in mind.

Windows Near Stairs and Landings

Windows near stairways, ramps, and landings also fall under safety glazing requirements. A fall on a staircase creates significant force, and if someone makes contact with a nearby window it will break. The glass location relative to the stairs and walking surface helps determine whether safety glazing is needed.

Large Windows in High-Traffic Areas

Large expanses of well-cleaned glass can sometimes be mistaken for an open passageway, particularly when they are positioned near floors and walking areas. Not every large window needs to be tempered. Size is only one consideration. Location, exposed glass area, height above the floor, and surrounding features all affect whether safety glazing is required.

Do Replacement Windows Have to Use Tempered Glass?

No. Tempered glass isn’t required for every replacement window. A typical bedroom window positioned several feet above the floor, for example, may not need safety glazing. A similarly sized window next to a bathtub or door may have different requirements. This is one reason homeowners shouldn’t assume the glass currently installed in their house is the glass they should use for the replacement. Older homes contain windows installed under previous building standards. Sometimes previous work wasn’t completed correctly. Before ordering replacement windows, evaluate each opening to determine the appropriate glass.

Can You Replace Regular Glass With Tempered Glass?

In many cases, yes. You can specify tempered glass when ordering a replacement window or insulated glass unit. The correct solution depends on the design and condition of the existing window. Sometimes only the glass or insulated glass unit needs replacement. In other situations, replacing the complete window makes more sense. Signs that a complete window replacement may be worth considering include:

•   •  Drafts around the window
•   •  Rot or deterioration around the frame
•   •  Failed insulated glass seals
•   •  Condensation between panes
•   •  Windows that are difficult to open or close
•   •  Poor energy efficiency
•   •  Water intrusion around the opening
•   •  Significant deterioration of the existing window

Replacing only the glass won’t correct problems with a failing frame, poor installation, or damaged components. A complete evaluation determines whether glass replacement, insert replacement, or full-frame window replacement is the better option.

Can Tempered Glass Be Used in Energy-Efficient Windows?

Yes. Choosing tempered glass doesn’t mean giving up the energy-efficiency features available with modern replacement windows. “Tempered” describes how the glass has been treated for safety. Other terms, such as double-pane, Low-E, and argon-filled, describe different characteristics of the window’s glass package. These features can often be combined.

Double-Pane Tempered Glass

Tempered glass can be incorporated into an insulated glass unit with two panes of glass separated by a sealed space. Depending on the window and safety requirements, one or more panes may be tempered. The insulated glass unit helps reduce heat transfer through the window while the tempered pane provides the necessary safety characteristics.

Low-E Tempered Glass

Low-emissivity, or Low-E, coatings are also used with tempered window glass. Low-E coatings are designed to control heat transfer and solar energy through the window. This improves comfort and energy efficiency throughout Nebraska’s changing seasons. Low-E coatings and tempering perform different jobs. Homeowners generally don’t have to choose one or the other.

Argon-Filled Tempered Windows

Argon gas is placed between panes in certain insulated glass units to improve thermal performance. A replacement window can therefore incorporate tempered safety glass along with insulated panes, Low-E coatings, and argon gas. The goal is to choose a complete glass package appropriate for the location of the window and the home’s energy-efficiency needs.

Should You Upgrade to Tempered Glass Even When It Isn’t Required?

Tempered glass generally costs more than standard annealed glass because of the additional manufacturing process. There are situations where a homeowner may consider tempered glass even when it isn’t specifically required.

For example, you may want additional safety glass in a room where children frequently play or in an area where the window is more likely to be struck accidentally. You may also want to discuss large windows in busy living areas with your window contractor.

More tempered glass isn’t necessarily better for every project, though. The right glass package should balance safety, performance, cost, and the home’s design. A Tevelde and Co. window professional will help you identify where safety glass makes sense and where standard residential window glass is appropriate.

Choosing Tempered Replacement Windows for Nebraska Homes

Safety glass is only one part of choosing replacement windows. Nebraska homes experience hot summers, freezing winter temperatures, strong winds, storms, and significant temperature changes throughout the year. The entire window needs to be selected and installed with those conditions in mind. When comparing replacement windows, consider the complete system, including:

•   •  Frame material
•   •  Insulated glass construction
•   •  Low-E coatings
•   •  Gas fills
•   •  Spacers
•   •  Weatherstripping
•   •  Window seals
•   •  Installation method
•   •  Flashing and water management
•   •  Insulation around the opening

A high-quality glass package won’t compensate for a poorly installed window. Gaps, inadequate insulation, damaged frames, or water-management problems around the opening will undermine the performance of an otherwise good window. The best approach is to evaluate the existing opening first and then select a replacement window that addresses its safety, performance, and installation requirements.

Get Help Choosing the Right Replacement Glass for Your Nebraska Home

You shouldn’t have to determine building-code requirements or glass specifications on your own before replacing your windows. Tevelde & Co. will evaluate your existing windows and help you determine the right replacement approach for your home. That includes identifying locations where tempered safety glass may be appropriate, evaluating the condition of existing frames, and reviewing options for energy-efficient glass packages.

We help you compare frame materials, window styles, glass options, and installation methods so the finished window fits your home and performs properly in Nebraska’s climate. If you’re considering new windows, contact Tevelde & Co. to schedule a consultation and discuss your replacement window options.