"Jerry Built" ] wrote in message
...
Dean Jarratt wrote:
This morning...about 3:30AM I heard a strange noise (loud enough to wake
me up).... [ ] I got up to investigate...and [] noticed that the small
double glazed window in the front door was cracked quite badly (multiple
cracks, almost on the point of being smashed). []
Is it possible for the sub-zero temperates to filter through an outer
pane
of double glazing and smash the inner pane? Would it be possible if the
outer pane was old and/or unnoticable damaged?

The only time I've heard of this happening it turned out that a plate
fell of a wall hanging and bounced down the stairs, hitting the pane
and breaking it. If it's a small pane, it's unlikely to be a thermal
effect - consider the temperature differential, it's tiny. Where in
the door is the glazing panel? What is the door made of?

The door is one of those white PVC doors, and the window is pretty much
central...above a letterbox which is placed at just below half-way up the
door.

I'll have to check the outside pane again more thoroughly...I think.