They may have been advertised as such but simple physics
says it ain't so.

Your door, at 48" x 78", has 3744 sq-in of surface area.
At a very mild pressure differential of 1 psi there would be
almost 2 tons of force trying to push the 2 panes together.
At 14psi differential this force is about 26 tons. No window
I know of will support this kind of force.

Show me the data. Otherwise I'm not a believer.

Art


"Robert Bonomi" bonomi@c-ns. wrote in message
...
In article FbDPa.36743$H17.10746@sccrnsc02,
Wood Butcher wrote:
It's the latter. A vacuum would be the ideal insulator but
nobody has managed to engineer a window that is strong
enough to keep the panes from flexing inward and touching
and/or breaking.

BZZZT! Vacuum panes exist. 'big' ones. We had 'em for 'sliding glass
doors'
opening onto a patio. 4' wide, 6'6" tall. installed in the mid 60's

Art