Condensation on glass doesn’t always mean poor insulation—it really depends on where it’s forming. If it’s on the inside, it can be more about indoor humidity levels, but if you see moisture between panes, that usually points to a failed seal. I found this breakdown from https://www.screensandwindows.com/blog/window-installation-vs-window-replacement-whats-better-for-everett-homes helpful when trying to understand whether the issue was with the glass itself or the overall window setup in Everett, WA.