Problems can occur with a sealed unit if it is not sealed correctly during the manufacture of the window.
A Double Glazed unit is likely to fail within a short time-frame if a unit is not sealed all the way round correctly when made.
This sort of defect could show within a year of production.
10% OFF ALL REPAIR JOBS UP TO THE END OF FEBRUARY 2024, JUST QUOTE "WINTER DISCOUNT"
Glaze It & Lock It will replace sealed units of any age and make.