Every once in a while we calls about window glass cracking or exploding on it's own.
Yes, it happens. Glass is not very forgiving. Even with tempered glass, it has it's weakness.
Heat
Like most things, temperature changes can cause the glass, frame, and whole system to fluctuate. Quick changes in temperature can cause glass to crack.
Settling
Buildings settle multiple times over their life span. This can cause drywall cracks, foundation cracks, and the pressure from it can cause a shift in the window system causing the glass to crack. There is not much you can do to prevent this from happening.
Gases
Some window units are made with a gas called Argon. Argon can help with insulation and the transfer of heat through the glass. Once a seal is broken, it causes the gas to leak and creates a suction motion with the panes. The panes get pulled inward due to the exchange between the air getting in and the argon escaping, thus causing the panes to crack.
Fun Fact: Even if the seal is intact, Argon still leaks on average 1% per year.
Possible Prevention (of heat related issues)
There are some things you can do to help prevent this from happening, but of course nothing is ever 100% guaranteed.
Film - If your windows get a lot of sun coming through, applying a film may help. Although we do not provide filming services, we recommend this if Low-e glass is not an option.
Low-e Glass - Helps to reflect rays and reduce the amount of ultraviolet and infrared light coming in. This does not affect the visible light. Some HOA's and landlords do not allow for this, and applying a film may be a better option. There are multiple types of Low-e glass, it just depends on the type of results you are looking for.
Tempered Glass - Tempered glass is made to withstand heat. It is strengthened through thermal and chemical treatment, and can withstand temperatures of up to 470 degrees.