rr2254545 wrote:
Have to have them when you camp in cold weather like we do
Yes, quality dual-pane windows can be very nice.
But the dirty little secret is that, in the RV industry, a lot of dual pane windows are sub-standard, as are many other components used by RV OEMs; they're prone to problems.
The problem usually manifests itself as fogging betweeen the panes, caused by poor quality seals, and it's not at all uncommon. The Tiffin Class A we bought used had a fogging problem in the passenger side front window when we bought it. We went to the factory service center, which recognized the problem as common, and had it replaced with a single pane assembly they had readily available.