There are many things on earth that you don’t want getting into your food, and glass is one of them. What happens when something that you cook in (and on) happens to be made of glass? Something like your oven? For most consumers, a glass oven door or cook-top provides minimal risk. However, lately, many people have been complaining about shattering or even exploding glass oven doors. Landmark Home Warranty has even had a few customers who have experienced this themselves. Since we don’t generally cover something like an exploding glass oven door, we set out to research more about this phenomenon, and figure out why this was happening and what consumers could do about it.

Oven Doors Shattering: How Common Is It?

From 1996 to 2013, there were around 440 complaints across different brands on Consumer Affairs, which represents 0.02% of ovens in the world. According to a King5 news report in 2014, some brands online complaints about this problem have increased from 19 in 2011 to more than 62 in 2013. So although it might not be a huge problem, it’s a problem that seems to be increasing over the last few years. If you simply Google the words “exploding oven door” you’ll have hundreds of hits on news stories about unhappy customers, people asking for advice, and reports on why and how these glass doors happen to shatter. While it’s not going to happen to every oven door out there, it’s a common enough problem that it’s even gone to the Consumer Product Safety Commission. Although the CPSC hasn’t opened a formal investigation into the phenomenon, they have stated that they intend to “follow up on the reports” and that as long as the glass is tempered correctly it follows “safety standards.” This safety standard the CPSC is talking about is that of tempered glass – the type of glass almost all ovens are made from. 

What is Tempered Glass?

Tempered glass is around four times stronger than regular glass. It is designed to handle more pressure and break more “safely” than other types of glass. Instead of large, sharp shards that can cut deeply, tempered glass breaks into small dull-pebbled shards. These pebbles of glass injure individuals far less than regular glass.

Tempered glass is made by quickly heating the glass up to more than 1,200 degrees Fahrenheit and then running it through a highly pressured cooling process. High-pressured air blasts the surface of the glass and cools the outer surface faster than the center. Thus, as the center of the glass cools, it pulls back from the outer surfaces, creating tension, which gives the tempered glass strength.

Although this tempered glass is stronger, and shatters more safely than other glass, it has its problems. Because of the tension the glass is under, if there are micro-stresses on the glass, it can shatter easily.

Why Do Oven Doors Shatter?

There are a number of ways a glass oven door can shatter, but most of them have to do with tiny cracks that develop from something hitting the glass. Some of these micro-fissures are created when the glass is tempered, while others are created when something small bumps against the glass in the oven, like a pan, diamond ring, or metal spoon. These fissures can handle the stress, until one day they simply give out. The continual heating and cooling of the stress fracture can cause it to become larger and larger, until it eventually weakens the glass. It can take years before the glass shatters, usually long after any appliance warranty will cover the breakage. At that point, there’s virtually no way to tell if the break was caused by something bumping up against the glass while in the oven, or a defect from the manufacturer that wasn’t caught. There is no fool-proof way of catching these micro-fissures unless a glass company does something called water-bathing, which is uncommon and extremely expensive.

How to Prevent your Oven’s Door from Shattering:

So what can you do to make sure you’re not in danger of having your glass oven shatter? Here are a few tips that are being passed around from oven manufacturers:

• Never bump your oven door with pots and pans. The smallest crack or nick could cause a stress fracture that could “explode” at a later time.
• Never slam your oven door.
• Never close your oven door without first making sure your oven racks are all the way in. Don’t use the door to close the oven racks. Metal can scratch the glass, causing breakage.
• Never run the self-cleaning feature on your oven.
  • Extreme amounts of heat can not only damage the internal components of your oven, but they can also cause the glass to break on the internal portion of your oven. Generally, self- cleaning features are a selling point, but you can get most burnt on food in your oven using heat free methods.

What to Do if your Oven Door has Already Shattered:

Facing a shattered door already? Although most warranties won’t cover the problem since it isn’t caused by “normal wear and tear”, it may be covered by the manufacturer as a manufacturer defect.

1. Take pictures, videos, and written explanation of what happened/ what was occurring while the oven door shattered.
2. Contact the manufacturer and share your story, tell them you want the oven door replaced because of a manufacture defect.
3. Report your story to the Consumer Product Safety Commission.

Although a home warranty will not repair or replace your oven door shattering, we do our best to help keep our customers educated and protect them when their systems and appliances fail from normal wear and tear (or old age). For more information on what a home warranty can do for you to protect your budget and your home, go to www.landmarkhw.com.