12 Types of Glass for Windows and Doors

One of the most important aspects of purchasing a new window or door with glass is choosing the right type of glass for your home or business. Knowing which type of door or window glass to choose depends on your unique needs and desires for your windows or doors. There are several different types of glass to choose from with their own key advantages. This includes:

12 Types of Glass for Windows and Doors

Annealed Glass
Float Glass
Gas Filled Glass
Heat Strengthened Glass
Insulated Glass
Laminated Glass
Low E Glass
Mirrored Glass
Tempered Glass
Tinted Glass
Textured Glass
Wired Glass

When beginning the window or door buying process, it’s normal to be unaware of all the different types of glass available to you. It isn’t as easy as just choosing whatever the standard glass type is, however, as the type of glass you choose will affect the quality, longevity, energy efficiency, security, privacy, and safety of your glass.

Considering these essential factors, it’s worth taking the time to research and understand the different types of glass for doors and windows. That way, you can make an informed decision to pick the glass that best serves your home or business.

12 Types of Glass for Windows and Doors

1. Annealed Glass

Annealed glass is a type of standard glass that has not been heat-treated or coated. Annealed glass is a type of float glass that goes through a slow cooling process to increase its strength and durability.

While it is somewhat stronger than float glass, it is not nearly as strong as tempered, heat-strengthened, or laminated glass. Moreover, when broken, it shatters into multiple sharp-edged shards.

Annealed glass is a very basic type of glass for windows or doors. This makes it less expensive, but also means it has a greater risk of breaking and or causing injury. That said, the benefit of annealed glass is that it can be cut and re-shaped, if needed. It can also be used as a double window glaze—in other words, as a double pane window to increase its energy efficiency.

Annealed glass can be further treated to enhance its strength and or energy efficiency. However, once treated, the glass is no longer annealed glass and is now classified as whatever it was treated to become, such as low e glass or tempered glass.

2. Float Glass

This is glass in its most basic form, and does not go through any particular heating or cooling process. Float glass can also be referred to as annealed glass. Though similar, they go through a slightly different cooling process in which annealed glass is cooled more slowly.

Float glass is used to make a large glass pane, which can be further treated or cut depending on its intended use. It’s made by pouring molten glass into a molten tin, which gives it shape and smooths the glass surface, making it clear and ready for use.

Typically, tempered or heat strengthened glass is made from either float or annealed glass, and is cut to shape before the heating and cooling process.

Because float glass is the most basic glass type, it’s also the most fragile and least expensive. It isn’t commonly used for home glass windows or doors because of its fragility. Moreover, when broken, it shatters into sharp shards, which can be dangerous. Because of this, float glass isn’t allowed to be used in a commercial door or window setting.

3. Gas Filled Glass

Gas filled glass is a type of insulated glass, and refers to a double or triple pane window filled with gas. This type of glass is also called “gas fills.”

The type of gas used in the window or door glass is typically krypton, argon, or a mixture of both. However, the type of gas used depends on the manufacturer. During the manufacturing process, the gas is inserted between the glass panes via a small hole along the window spacer.

The purpose of gas filled glass is to enhance insulation performance. Argon and Krypton gas don’t conduct heat well when compared to air. Because of this, they are effective insulators and prevent frost buildup on the glass during cold weather.

Argon gas is more commonly used than krypton gas, and is considered the industry standard for double pane windows and door glass. Argon is less expensive than krypton and is more reliable and readily available. Moreover, argon is naturally occurring, non-toxic, odorless, and non-reactive. If a window or door glass breaks that is gas-filled, the argon gas leak will dissipate quickly and not cause damage to the environment or building occupants.

Krypton gas is more expensive than argon because it’s denser and a better insulator. That said, krypton is less readily available, so it’s harder to come by. It is also a non-toxic, odorless, and naturally occurring gas, though it can also be man-made. Because of its density, it is more effective in smaller spaces, so it’s commonly used in triple-pane glass structures.

Choosing insulating glass, such as gas filled glass, helps stabilize your home’s temperature, which increases your home’s energy efficiency. This helps you save on energy bills each month and increases the longevity of your window and door glass.

4. Heat Strengthened Glass

Heat strengthened glass is a strong and durable glass that is two-times stronger than regular annealed glass. As the name implies, it goes through a heating and cooling process that changes its structure, making it harder to break and more resistant to wind load and thermal stress than annealed glass.

Heat strengthened glass is made from annealed glass that is heated to a temperature of about 1,200 degrees Fahrenheit. It is then exposed to cool air, creating surface and/or edge compression in the glass. Tempered glass goes through a similar process, but the cooling is much more rapid, creating increased internal tension as the outer surface compresses.

This glass type is not as strong as tempered glass, and isn’t considered safety glass. This is because heat strengthened glass still produces large shards of glass when broken.

That said, heat strengthened glass is the industry standard whenever a strong glass is needed, but safety glass isn’t required. Because of this, home windows and doors with windows will often have heat strengthened glass as a higher-quality, more durable glass option, especially when compared to annealed or float glass.

5. Insulated Glass

Insulated glass is another way to describe Low-E glass, gas-filled glass, and or heat-retention glass. However, insulated glass units (IGU) specifically refer to windows or door glass with two or more glass panes, such as a double pane or a triple pane window, with an air space between the window panes.

Insulated glass is often gas filled glass, but not always. Some insulated glass units contain only air space, rather than a gas insert. The ones that do contain gas go through the same process as discussed in the gas filled glass section.

The purpose of insulating glass is to diffuse heat transfer, whether that’s heat coming from the sun or the heat from your home. Insulated glass stabilizes your home’s temperature by preventing heat loss from internal temperatures. On the other hand, it prevents heat from coming in, which keeps the internal temperatures cool and comfortable in the summer.

Insulated glass is designed to increase your home or business’s energy efficiency, and is the industry standard for all residential or commercial storefront windows. You can augment your window’s insulating performance by choosing gas-filled glass, a triple pane window, or by adding a special coating, such as Low-E or window tint.

6. Laminated Glass

Another type of safety glass or glazing is laminated glass. Laminated glass doesn’t go through a heat process like tempered or heat strengthened glass. Rather, it’s made of two or more panes of annealed glass joined together by a layer of polyvinyl butyral (PVB), a type of plastic. Laminated glass could have several layers of glass and PVB or just one layer of PVB between glass panels. The more layers of PVB there are, the safer and stronger the glass.

The biggest advantage of laminated glass is that it doesn’t shatter to the ground when broken. Rather, the broken glass sticks to the plastic. While laminated glass isn’t considered shatterproof glass, it comes close with its shatter-resistant makeup. The PVB also makes laminated glass much harder to break than regular annealed glass.

Other benefits of laminated glass include soundproofing and UV radiation reduction. The plastic portion may be clear or tinted, depending on your personal preference.

Laminated glass is ideal for commercial structures, as it protects the building from break-ins and hazardous sharp, broken glass. It is also beneficial for areas that experience extreme weather, such as large hail, tornadoes, or hurricanes. It obviously isn’t strong enough to hold up against direct pressure from such elements, but it will be much safer to clean up.

This type of safety glass is often used for skylights, automobile windshields, glass doors, glass railings, and glass floors.

Laminated glass is more expensive than tempered glass, but it is the preferred choice if you want the best safety glass there is. For home windows, heat strengthened or tempered glass is more affordable and common, as broken windows aren’t as much of a concern in a residential setting.

7. Low E Glass

Low E glass, short for low emissivity glass, is a type of glazing created to enhance a window’s insulating performance. A special coating is applied to the glass to minimize the amount of infrared and ultraviolet light that comes through without sacrificing the amount of natural light coming into the space. This coating is microscopically thin, so it isn’t visible to the naked eye.

As a transparent coating, it reflects heat away from the glass. In summer, it reflects the heat away from the home, keeping internal temperatures cooler. In winter, it reflects the warmth from your house back into the home so that it doesn’t escape through the glass. This specialized window and door glass glazing is the top choice for energy efficiency and keeping the internal house temperature steady.

When choosing Low E glass, there are two types to consider: passive Low E coatings (hard coat) and solar control Low E coatings (soft coat). The difference between the two lies in how the coating is applied to the glass, and they both have unique advantages.

For those who live in the United States, soft coat Low E glass is recommended, as this coating offers the highest-performing solar control, which means it performs better than the hard coat at keeping the sun’s heat away from the home. The hard coat is preferable in cold climates with mild summers where heat from the sun is welcome.

Although it’s an investment up front, Low E glass will pay for itself through lower energy bills, as the heating and cooling system won’t have to kick on as frequently. It’s estimated that about 90% of window and door heat loss occurs through glass. Because of this, you’re guaranteed to save quite a bit on utility bills with Low E glass.

8. Mirrored Glass

Most home windows aren’t going to have mirror glass, but it may be a special element for a certain glass door you may have in your home. Rustica offers two types of mirror glass: mirropane and mirror. Mirror glass is a one-sided mirror with a wooden or metal back, depending on the door you choose.

Mirropane glass can be used for either a window or glass door, as it’s a one-way mirror that performs as a mirror on one side and is translucent glass on the other. The purpose of mirropane glass is for increased privacy, as those walking by can’t see in, but you can still see out.

Mirror glass is treated with a metallic substance or metal coating that offers mirror-like properties. It can also be made by placing a metal coating on one side of a pane of glass and then sealing it with a protective sealant.

9. Tempered Glass

Tempered glass is a popular type of safety glass, and it’s used for a wide range of functions. Tempered glass differs from annealed glass by how it breaks and how it’s made.

When annealed glass breaks, it shatters into sharp shards. When we think of a moving vehicle or an office building with giant windows, it would be extremely dangerous for sharp shards of glass to fall on those nearby. Tempered glass is much safer, and it’s four times stronger than annealed glass. Rather than shattering into sharp-edged shards when broken, tempered glass breaks into small, dull cubes that pose less of a threat to bystanders nearby. Plus, it’s harder to break in the first place because of its strength.

Tempered glass is made from regular glass that has been heated at extreme temperatures—more than 1,000 degrees Fahrenheit. Then, the glass is rapidly cooled by a machine that blows frigid temperatures at it. Through the exposure to extreme temperatures, the glass changes its structure. The outside of the glass cools much faster than the internal glass, which creates tension internally as the outer surface compresses. This is how glass is ‘tempered’ and becomes stronger and safer than annealed glass.

Tempered glass windows and doors are the preferred glass type for commercial buildings and where human safety is a concern. Because it’s harder to break, it’s a preferred window glaze for businesses or homes that want to prevent break-ins. It is also commonly used for household appliances, shower doors, automobile windows, glass table surfaces, and glass doors.

Tempered glass is a custom window glaze, as it has to be made to size and can’t but cut after going through the heated process as cutting may damage the tempered structure. Keep this in mind when ordering custom windows if you would like the window to have tempered glass.

10. Tinted Glass

Tinted glass is a well-known glass type often used in vehicles for an added layer of privacy. That same effect can be achieved on your home windows or glass doors. However, tinted glass isn’t just for privacy—it also provides energy efficiency, sun protection, and security for your home or business.

Tinted glass reduces ultraviolet light transmission. In other words, it lessens the amount of direct sunlight coming into your home. This protects your furniture, carpet, and wooden accents from fading over time while decreasing the heat that comes through your windows. In this way, it increases your home’s energy efficiency and saves on cooling costs.

Moreover, tinted glass can protect your health, especially if there is an abundant amount of direct sunlight streaming through the windows. It’s well-known that exposure to UV radiation can be harmful and increase the risk of skin cancer. Tinted glazing reduces ultraviolet rays by up to 99%, depending on the type of tint. This is why office buildings often have tinted windows, as employees often have to sit at a desk next to the window for multiple hours.

Finally, tinted glass can make your home or business feel more secure and private. If you opt for a safety glass that is also tinted, then you increase the safety of your home or business that much more. Feeling safe and secure in the privacy of our homes is so important for our well-being, and tinted windows can certainly help us feel that way.

Rustica offers a few different types of tinted glass for windows and doors. Because tint only modifies the color of the glass without changing its basic properties, tint can come in different shades and styles. Tint, frosted, and retro are just a few of our obscured glass styles.

11. Textured Glass

Textured glass, also known as obscured glass, patterned glass, or decorative glass, features a textured surface on one or both sides of the glass pane. The glass texture depends on the style and pattern, but for most styles, you can feel the texture when you run your hands over the glass. Some glass styles feature textured glass that is smooth on the surface, but still has a pattern within the glass.

During the glass-making process, molten glass is poured into a series of rollers that imprint a specific pattern onto the glass. These rollers can imprint on both sides of the glass or just one. Regular glass is also made this way, but the roller machines make the glass surface smooth rather than textured.

While obscured glass and textured glass are referred to as the same thing, obscured glass isn’t always textured. Some obscured glass styles are smooth, but are tinted or colored for privacy. Some styles can be both tinted and textured, while others are just textured. For clarity, the latter is commonly referred to as clear textured glass.

Patterned glass can be applied to other types of safety and energy-efficient glass styles, such as tempered glass and low E glass. Because of this, your custom replacement windows can have the safety, quality, privacy, and style you need—making textured glass a valuable and versatile custom glass option.

12. Wired Glass

Wired glass is regular annealed glass that contains a wire mesh. During glass production, the wire mesh is placed in the molten glass, which then cools and hardens around the wire. Wired glass is fire rated glass, though it is no longer considered safety glass by commercial building codes. This is because it's made with annealed glass, which isn’t strong enough to handle the impact of human weight and could shatter.

However, wired glass is still beneficial in any area that requires fire rated glass but isn’t in an area that is considered a “hazardous location.” If you’re interested in wired glass for a commercial building, you’ll want to check the building codes in your area to make sure that wired glass meets the safety requirements for that area. Generally, in order for glass to be considered safety glass that meets safety code requirements, it needs a special coating to strengthen it.

Wired glass is fire resistant because the wire within the glass holds it together when heat from the fire causes it to crack. Then, the heat causes the glass to melt and “heal” the cracks. The wire holds the glass in place throughout the process, preventing flame, smoke, and hot gasses to pass through it.

Which Type of Glass Do I Need?

With all the different types of glass for windows and doors, it can be difficult to determine which is best for your new window or door. However, there are a few things to consider that will help you figure out what type of glass is best.

For starters, the type of glass you need greatly depends on if it’s for a commercial or residential setting. Building code requirements will need to be researched for commercial windows and doors. These requirements are in place for human safety, and usually necessitate a type of safety glass, such as tempered or laminated glass, depending on its location. There’s much more flexibility for home windows and doors, and it’s usually up to the homeowner to decide what type of glass they want.

For high-traffic areas in the home, such as a front door, you’ll want to choose strong, break-resistant glass, such as heat strengthened glass or tempered glass. Using a weaker glass, like annealed glass, creates an increased risk of shattered glass, which can be dangerous.

For exterior home or commercial windows, you’ll want to consider an energy efficient glass, such as low E glass, gas filled glass, and double or triple pane glass. Increasing your window or door’s insulating performance helps cut energy costs. Insulating glass isn’t as important for interior door glass, as it doesn’t need to reduce UV rays or heat transfer.

Above all, consider your unique needs and project goals, and apply those to the type of glass that will best serve your needs and desires. If you need assistance determining which glass type is best for your new window or door, don’t hesitate to contact Rustica’s customer support. We’re happy to help you in figuring out which glass type you should choose.

Start Your Next Window or Door Project with Rustica Today!

The type of glass you choose will greatly affect your window or door glass’s strength, longevity, energy efficiency, safety, and more. Considering these important factors, you’ll want to choose the best glass for your residential or commercial needs.

Whether you need laminated safety glass for a business storefront, or low E glass for your new home windows, Rustica can help bring your next project to life. We specialize in custom windows and doors so you can design the perfect door or window for your home or business.