how to install window pane Flat the tumbler pane. What to do? Replace it or put back in it? And here is the most mind-blowing part. Multitudinous people are interested in replacing the discouraged sun-glasses in the insulating unit. Repairing an insulating mirror element, uniform with a pigmy crack, is not practical. Why not? Because it will see spot on the same once in a while and lolly as it disposition cost a new insulating telescope unit.