I acquired a double-glazed upvc window (second hand) that is exactly the si ze I need, but it has condensation between the panes. I've never replaced a sealed unit before. Is there much difference between between the various o fferings available from the various window nerchants, or are they much the same in quality and thermal resistance? Are there any types to avoid and ar e there types that are worth paying extra for (not including triple-glazed) . I often see brands that claim to be superior, and some with special gas t hat cost extra, but are they worth paying extra for?
Are double-glazed sealed units all the same thickness, or do I need to remo ve and measure the exact thickness of the failed one? How precise does the measurement need to be?
Many thanks,
JD