Stress cracks can form when there is a large difference between the temperatures inside and outside your home.
How to detect cracks in window and door.
You can usually find them near the edge of the window glass.
You can tell that a pressure crack has occurred due to the shape of the break in the glass.
Check to see if the caulking and weather stripping are applied properly leaving no gaps or cracks and are in good condition.
Another option for detecting air leaks is using an infrared thermometer which is a non contact thermometer that can measure the ambient air temperatures around window and door frames.
In most cases the crack will follow a curve in the shape of an hourglass.
Stress cracks start off small and then expand and grow across the glass.
Check the exterior caulking around doors and windows and see whether exterior storm doors and primary doors seal tightly.
Inspect windows and doors for air leaks.
If smoke blows sideways you likely have a leak.
The windows cannot withstand the pressure of these scenarios and will crack as a result.
Hold a lit incense stick by windows outlets doors and any other suspected areas.