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6 types of replacement window glass (Low-E, tempered, laminated, and more)

December 9th, 2021 | 20 min. read

6 types of replacement window glass (Low-E, tempered, laminated, and more)

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Windows at the top of a wall looking from the inside of a home. The windows are square and in a line with a blue sky and clouds behind.

When you’re shopping for new replacement windows, did you know that there are different options for the window glass?

Depending on your goals for your new windows, you’re going to want to customize the window glass so the window will look and perform how you want it to. 

There are many different types of window glass to fit your needs for energy efficiency, privacy, and aesthetics. So, what do you need to know about window glass types, and what are your options? 

Window glass can be insulated, Low-E, glazed, laminated, or tempered. Each of these types of glass will perform differently and even look different, which is why you need to understand the functions of each of these glass types and how they will make your windows look. 

Then, you can choose the right glass type for your replacement windows to get the best possible result for your project. 

Southwest Exteriors has been a window replacement contractor in San Antonio for over 32 years. We offer a variety of window types, like vinyl, fiberglass, and clad, with several different options for glass, like insulated, coated, and decorative glass. 

We know that looking at the different window and window glass types can be overwhelming. This is why our number one goal is to educate you on all your options and help guide you to the right solution for your window replacement project. 

This article will discuss the five different types of glass for replacement windows, how they perform, and what they look aesthetically.

After reading, you will know all about the different window glass types and choose which type is right for you.  


1. Low-E window glass

The first and most popular type of window glass is Low-E glass. Low-E stands for low emissivity. What this means is that there is low emissivity of harmful rays through the glass. 

How does Low-E glass work?

Low-E glass blocks infrared and UV rays that come from the sun. These rays bring heat into your home and can also damage your furniture if near a window. (The heat rays from the sun will absorb into the furniture and can cause deterioration and discoloration of your furniture.)

Low-E glass can come in levels with increasing layers, depending on the contractor. Each added layer will increase the rays blocked by the glass and increase the window's energy efficiency.

This will be the first type of glass you will want to look at if you want a window that will be energy efficient and keep your home cool. 

What does Low-E glass look like? 

If you have Low-E glass on your windows, you won’t be able to tell. This type of glass looks like normal glass, so you will have a window that blocks harmful rays without compromising the style.  

2. Laminated window glass

Laminated glass is a strong glass type. It is made by taking two or more sheets of glass and mending them together under high heat and pressure with a layer of PVB, or polyvinyl butyral, a strong yet flexible bonding material. 

How does laminated glass work?

The layered glass combined with PVB creates an incredibly thick and strong window glass. This glass will be a good fit if you fear a football will fly through your window or you live in an area with extreme hail or high winds. 

The more layers to the laminated glass, the stronger it is and the less likely it will break. If punctured, laminated glass can crack but will remain in one piece. This is because the PVB layer between the glass keeps the panes together, so it will not shatter all over. 

What does laminated glass look like?

The biggest aesthetic difference between regular glass and laminated glass is that laminated glass is much thicker. While you probably won’t be able to tell in the window, this may be something to consider for the look of your windows. 

3. Insulated window glass (Gas-filled windows)

Insulated glass in a window is another glass type that increases energy efficiency, next to Low-E glass. With insulated glass, the gap between panes is filled with a gas, typically krypton or argon, to provide insulating properties to the window. 

How does insulated glass work?

The gas between the panes of the window glass adds layers to the window. 

More layers = more insulation

Insulated glass has a guaranteed fill rate, which is a percentage of how filled the window is. The higher the guaranteed fill rate, the more insulating it is. Insulating your windows keep your home cooler in the summer and warmer in the winter. 

It is important to keep in mind that the gas between the panes will escape over time with an insulated window. While these gases are not toxic or dangerous, you must consider this inevitable process when looking at the fill rate of a window. 

What does insulated glass look like? 

Although the window will be filled with gas between panes, you will not be able to see the gas. This means that you will have all the energy-efficient benefits of insulated glass without compromising anything aesthetically. 

Most windows are made with at least two panes, although there are single-pane windows on the market. If you have a single-pane window, you cannot have insulated glass. 

4. Tempered window glass

Tempered glass is another type of glass that is engineered to be stronger than regular window glass. It is made by taking the glass and exposing it to extremely high heat, often placed in a tempering oven. 

How does tempered glass work?

When the glass is exposed to such high heat, it expands. Then, the glass cools from the outside in, meaning the outside starts to contract while the inside is still flexible and expanded. This creates compression between the inside and outside of the glass, which gives it its strength. 

When tempered glass is struck or breaks, it shatters into many small, marble-sized pieces rather than shattering into shards. Tempered glass is popularly used in car window glass. 

It is important to note that in some instances, tempered glass is necessary for windows if the window fits all of the following:

  • Larger than nine square feet

  • The bottom of the window is less than 18 in. from the floor

  • The top of the window is more than 36 in. (3 ft.) from the floor

  • There is a 36 in. (3 ft.) walkway on either side of the window

What does tempered glass look like? 

You will only be able to tell if the glass is tempered if it breaks. If the glass breaks, it will break into thousands of small pieces. Regular glass, when broken, creates uneven shards. This makes tempered glass a safer option if a window is in an area with a high probability of being broken.

5. Tinted window glass

Tinted window glass is exactly what it sounds like: a glass with a window tint. A tint in a window can either be used for aesthetic or energy-efficient purposes. 

How does tinted window glass work?

Tinted window glass has a special coating that adds a layer of protection to the window. This tint can be made in various colors, like green, yellow, blue, and grey. Tinted glass is used as a barrier not only to the sun's heat but also to the sunlight. 

You might be thinking, isn’t this what Low-E glass is supposed to do? Low-E glass only blocks the heat rays through the window, whereas tinted glass provides a shade to the window as well. The low-E glass allows for all the sunlight to come through the window without the heat. 

Think of tinted glass like putting sunglasses on. Your eyes are protected from UV rays (in most sunglasses) while also providing relief from the bright sun. You might be interested in tinted window glass if you get too much sunlight through one window, or the sun is constantly creating glares and blind spots around your home. 

What does tinted window glass look like?

Depending on the type of tint and how many layers, the tint will look different on every window. If you choose a colored tint, then the window will have a slight tint of that color. Different color tints can block different types of light, so that is something to keep in mind when choosing a tint other than how it will look. 

6. Decorative window glass

The last type of window glass we will cover is decorative window glass. Decorative glass deals with patterned designs that can be made as a window and the finish of the window glass as well. 

How does decorative window glass work? 

Decorative window glass can either be made with a specific finish or put into a design, depending on the contractor. Glass made in a specific finish, for example, is typically used for privacy purposes. This type of decorative glass might be ridged or have a textured finish that looks like a waterfall. 

The other type of decorative glass means that pieces of glass are cut to a specific shape and size and pieced together to create a design, like a flower or Texas star. 

While decorative glass does not have a specific function, it may be what you’re looking for if you want to add some personal style to your windows. 

What does decorative glass look like? 

Decorative glass can look any way you want it to. It’s purely decorative. If you are looking for a specific design, most manufacturers can create any design you like. 

If you are looking for a specific finish for privacy, this will depend on the manufacturer and what type of finishes they offer. 

Which type of window glass is right for me?

Now that you know the six types of window glass, you can choose which type of glass may be what you’re looking for. When choosing a glass type for your replacement windows, you must outline your wants, goals, and needs. 

  • If you want your windows to be more energy-efficient, then insulated and/or a Low-E glass might be your best option. 

  • If you need a window with strong glass that won’t break easily, then laminated or tempered glass may be right for you. 

  • If you want more privacy or customize your window to your style, then a tinted or decorative glass might be your best fit. 

It is important to know that any addition you make to your window will add to the total cost. Some higher-quality windows already come with a Low-E glass or are filled with insulating gas. They may already be tempered or laminated, which will be reflected in the cost of the window. 

However, things like tints, added Low-E coatings, and decorative glass will add on top of the initial cost of the window. 

Ultimately, the glass of your window makes up a large part of the entire window system. The glass will help protect your home, keep it insulated, and showcase your home, so you want to ensure you choose the best window glass for you. 

With Southwest Exteriors, we offer windows with Low-E glass and the options for added tints and decorative glass. We know that window might not be the first thing you think of with your replacement windows. However, we want you to know that not all window glass is created equal. 

This is why it is crucial to choose a window that is made with high-quality glass to perform how you need it to and protect your home. 

After learning about different types of window glass, you’re probably wondering how I choose the right glass for me? 

This article will answer exactly that question. Read more about what questions you need to ask to find the right type of glass for your replacement windows.