Comparing Annealed vs. Tempered Windows

Contents
- What Is Annealed Glass?
- What Is Tempered Glass?
- When Is Tempered Glass the Better Choice?
- Glass Safety and Building Code Requirements
- Visual Differences: What Happens When Glass Breaks?
- Can You Apply Window Film to Tempered or Annealed Glass?
- Cost Comparison: Which One Is More Budget-Friendly?
- Final Thoughts: Choosing the Right Glass for Your Project
When people shop for new windows or plan a renovation, they often hear terms like annealed and tempered glass. Both types are used in windows, but they're not the same. Each has its own strengths, safety levels, and best use cases.
The main question most people have is simple:
"What's the difference, and which one should I choose for my project?"
This article explains how these two types of glass are made, how they behave when broken, where they're commonly used, and what kind of safety they offer. The goal is to help you make the right decision for your home or building, based on how much strength, safety, or cost matters in your case.
What Is Annealed Glass?
Annealed glass is the most basic kind of glass used in windows. It's made by slowly cooling the glass after it's formed. That cooling process helps reduce stress inside the glass, so it's easier to cut and shape. Many homes and buildings still use annealed glass in places where safety isn't a big concern. It's affordable, and it works fine in low-risk areas, like small interior windows, cabinet glass, or picture frames. But there's a downside: when annealed glass breaks, it breaks into large, sharp pieces. Those sharp edges can be dangerous. That's why it's usually not allowed in places like bathroom doors or large windows close to the floor.
What Is Tempered Glass?
Tempered glass is much stronger than annealed glass. It's made by heating the glass to a high temperature and then cooling it down very fast. This process changes how the glass behaves—it becomes 4 to 5 times stronger and much safer if it breaks. When tempered glass breaks, it doesn't form sharp pieces. Instead, it shatters into small, round chunks that are far less likely to cause injury. Because of that, it's used in places where safety matters more, like sliding doors, shower enclosures, and large windows near the ground. Tempered glass does cost more than annealed, and once it's made, it can't be cut or reshaped. That means the size and shape have to be final before it goes through the tempering process. Discover how window film can transform your building during repositioning projects. Read our detailed blog to learn more.
When Is Tempered Glass the Better Choice?
Tempered glass is the right choice in places where safety and durability are more important. People often use it in:
- Bathrooms – for shower doors and bathroom windows
- Entry doors – especially full-glass or sliding doors
- Windows near the floor – where someone could fall into the glass
- Commercial buildings – in storefronts, offices, and public areas
- Outdoor areas – like balcony railings, patio doors, or glass fences
- High-traffic zones – like hallways or busy areas in the home or office
Tempered glass is also a smart option in homes with pets or kids, where accidents are more likely. It's built to handle more impact and heat, so it lasts longer in tough conditions. In many of these situations, it's not just a smart choice—it's a required one.
Glass Safety and Building Code Requirements
In many places, building codes require tempered glass in certain installations. These rules exist to protect people from injury if the glass breaks. Tempered glass is usually required:
- In or near bathrooms
- In doors and door sidelights
- In windows less than 18 inches from the floor
- Near stairs, ramps, or walkways
- Anywhere glass is larger than a certain size and easy to bump into
Homeowners and builders should always check local building codes before buying or installing glass. Every region has its own rules, and not following them can lead to problems. If the wrong glass is installed, it could mean: - Failed inspections
- Extra costs for replacement
- Liability if someone gets hurt
Using tempered glass where it's required isn't just about following the law—it's about making sure the space is safe for everyone who uses it. Protect your windows with our elegant and efficient exterior neutral adhesive window films. Explore the SOLAR SCREEN® solar control range here for a perfect blend of comfort and style.
Visual Differences: What Happens When Glass Breaks?
Let’s say someone accidentally hits a window with something hard. If that window is made of annealed glass, it will break into big, sharp pieces. Those pieces can be dangerous. They can cut someone, and they’re hard to clean up safely. That’s one of the main reasons people avoid annealed glass in places where accidents might happen. But if the window is tempered glass, the break looks very different. Instead of sharp shards, the glass shatters into lots of small, rounded pieces. These pieces look like little pebbles. They’re much less likely to hurt someone, even if the whole window breaks. Most people don’t think about this difference until they see it. But when safety is a concern, how the glass breaks really matters. Tip: If you can, look at a side-by-side photo of annealed vs. tempered glass breakage. The difference is easy to see.
Can You Apply Window Film to Tempered or Annealed Glass?
Yes, you can apply window film to both types of glass—annealed and tempered. But it’s not always simple. Not every film works with every kind of glass. Some films can cause problems, especially on tempered glass, because of the way they handle heat. If the film holds too much heat, it can stress the glass and even cause it to crack. If you’re looking for options, start here: glass treatment solutions for homes. You’ll find films made for both safety and comfort, without damaging your windows.
Cost Comparison: Which One Is More Budget-Friendly?
Annealed glass is cheaper than tempered glass. That’s one of the main reasons people choose it for simple or low-risk projects. It’s easier to make, and it doesn’t go through the extra heating process that tempered glass does. Tempered glass costs more, but for good reason. It’s stronger, safer, and often required by building codes. The higher price covers the added safety and durability.
Final Thoughts: Choosing the Right Glass for Your Project
Here’s the bottom line:
- Use annealed glass when safety isn’t a big issue and cost is more important.
- Use tempered glass when safety matters, when the glass is in a risky location, or when local codes require it.
Every project is different. That’s why it’s a good idea to talk to a professional before buying or installing any type of glass. A trained expert can look at the space, the risk level, and the legal requirements, and help you choose the best solution. If you’re also thinking about privacy, UV protection, or energy savings, take a look at:
- Safety window films for tempered glass
- Glass treatment solutions for homes They can make your glass even safer and more comfortable to live with.