Replacement windows for 8002

It’s always amazed us that Florida windows are single glazed; I understand there’s less need for winter heat than back in Massachusetts – but surely there’s a/c energy savings in the summer?
Whatever the reason, we finally decided to replace some windows with double glazed units – my office (front bedroom) is priority since it is north facing and the huge old window leaks terribly; it gets cold in there on cold winter days (well, cold by Florida standards at least).
We chose in fact to replace the windows in all four bedrooms – the other bedrooms was mainly to reduce exterior noise; we chose Window World (mostly because they seemed to be about the only company around!)