Annealed Glass vs Tempered: Which Glass Type Is Best?

Annealed glass and tempered glass are two commonly used types of glass, but they have different properties and uses.

This article will compare annealed glass vs tempered glass, highlighting the differences in strength, safety, and where you’ll find them.

Annealed Glass: Properties and Applications

Annealed glass is just ordinary “float” glass that’s been cooled slowly to reduce any internal stresses. It’s typically less expensive than tempered glass and easier to cut.

Unfortunately, annealed glass is prone to breaking into long, sharp shards, so it can be a safety hazard.

Because of its safety issues, annealed glass is best for decorative applications, interior design, picture frames, and small craft projects where safety isn’t a big concern. You might see it in cabinet doors, kitchen cupboards, indoor furniture, and decorative pieces.

Tempered Glass: Properties and Applications

Tempered glass starts out as annealed glass, but it’s been heat-treated to make it stronger. How strong? It’s typically four to five times stronger than annealed glass and can handle five to seven times the pressure.

Another plus: Tempered glass doesn’t shatter into sharp shards when it breaks. Instead, it breaks into small, relatively harmless blunt bits.

Tempered glass does have its limitations, though. You can’t cut it or alter it after it’s been tempered, and it typically requires a professional to install it.

Because of its strength and safety, tempered glass is great for high-impact areas or anywhere building codes require safety glass. Some common uses include:

  • Shower doors
  • Automobile windows
  • Glass railings
  • Doors
  • High-end retail displays

Annealed vs. Tempered Glass: Key Differences

Here’s a quick rundown of the key differences between annealed and tempered glass:

  • Strength: Tempered glass is much stronger – up to seven times stronger, in fact – than annealed glass.
  • Breakage: Annealed glass breaks into dangerous, sharp shards. Tempered glass breaks into small, relatively harmless pieces.
  • Safety: Because of its breakage pattern, tempered glass is considered a “safety glass.”
  • Cost: Annealed glass is generally cheaper to buy.
  • Customization: You can cut and modify annealed glass after it’s made. You can’t do that with tempered glass.

Summary

When you’re deciding between annealed glass and tempered glass, it’s important to consider safety, strength, cost, and the degree to which you can customize it.

If safety is a priority, tempered glass is the clear choice. If you’re not sure which kind of glass to use for your project, talk with experienced glass professionals.