Tempered vs. Annealed: The Critical Safety Differences Every Parent Should Know.

  January 21, 2026

It’s the sound every parent dreads.

You are in the kitchen making dinner. The kids are playing in the living room. You hear a thud, a gasp, and then the sickening sound of glass shattering.

Your heart stops.

accidents happen. Baseballs go off course. Kids trip. Dogs get the “zoomies” and run into the patio door.

But here is the most important question: When that glass breaks, how does it break?

Does it crumble into safe little pebbles? Or does it turn into large, jagged knives?

The answer depends entirely on whether you have Tempered or Annealed glass.

Most homeowners in Surrey and the Lower Mainland don’t know the difference. But if you have young kids running around, knowing this difference could save a trip to the emergency room.

What is Annealed Glass? (The “Standard” Option)

Annealed glass is your standard, basic window glass.

It is what you find in most older homes. It is affordable and it works great for keeping the weather out.

But it has a weakness. It is brittle.

If a stray hockey puck hits a pane of annealed glass, it doesn’t just crack. It snaps into large, long, razor-sharp shards. We call these “guillotines” in the industry because they are heavy and incredibly sharp.

If a child falls into an annealed glass door, those shards can cause serious, life-changing injuries.

What is Tempered Glass? (The “Safety” Option)

Tempered glass is different. It is the superhero of the glass world.

To make it, we take standard glass and put it through a special oven. We heat it up to over 600 degrees Celsius and then blast it with cold air to cool it down instantly.

This process changes the chemistry of the glass. It puts the outside under tension and the inside under compression.

The result?

1. It is Tough:

Tempered glass is about 4 to 5 times stronger than standard glass. A soccer ball that would shatter a normal window will often bounce right off a tempered one.

2. It “Pops” Instead of Slicing:

This is the critical safety feature. If you do manage to break tempered glass (and it takes a lot of force), it doesn’t create shards.

It explodes into thousands of tiny, dull cubes. They look like rock salt or popcorn.

If a child falls through a tempered glass door, they might get a few scrapes and bruises, but they won’t get deep cuts. It is the same glass used in your car’s side windows and shower doors.

The “Safety Zones”: Where Do You Need It?

You don’t need expensive safety glass in every single window of your house.

However, the Canadian Building Code is very strict about “Safety Zones.” These are areas where human impact is likely.

At Shine Glass & Windows Ltd., whenever we do a replacement in these zones, we always use tempered glass. It is non-negotiable for safety.

Here is where you absolutely need it:

• Patio Doors: Any sliding door or French door is a prime target for trips and falls.
• Sidelites: Those narrow windows right beside your front door? They need to be tempered because people bang into them with groceries or bags.
• Low Windows: If a window is close to the floor (usually within 18 inches), it needs to be safety glass. A stumbling child could easily go through it.
• Bathrooms: Any glass near a tub or shower must be tempered. Slipping on a wet floor is dangerous enough without worrying about breaking a window.

The “Bug” Check: How to Test Your Windows

So, what is in your house right now? You can check yourself. You don’t need any tools. Go to your patio door or a low window. Look very closely at the four corners of the glass. You are looking for a faint, etched stamp. We call it the “bug.” It will usually say “Tempered,” “Temp,” or have a certification code (like SGCC).

If you see the stamp, breathe easy. You are safe.

If the glass is totally clear with no stamp, it is likely standard annealed glass.

Is It Time for an Upgrade?

If you find annealed glass in a “high traffic” area – like a low window in a playroom or an old sliding door – don’t panic. But do pay attention. Many parents choose to proactively replace these specific glass units for peace of mind. It is a small investment compared to the safety of your family.

At Shine Glass & Windows, we can swap out just the glass unit without removing the whole window frame. We replace the dangerous glass with high-strength tempered safety glass, so your kids can play freely, and you can stop worrying about that “crash.”

Unsure if your windows are safe? Contact Shine Glass & Windows today. We can perform a quick safety check for you.