Dual pane windows in RV's is a terrible idea. First off you have a giant windshield up front that isn't dual pane. Unlike a house, your motorhome is being shaken, rattled, and rolled while going down the road, hence the seals will leak. Don't fixed the dual pane windows by resealing, because in a few years, they'll just leak again. There are companies that will replace the dual panes with a thicker single pane window and you end up with about the same insulation factor and guess what............you'll never have a window leak again. The cost is about the same as resealing.............so it's a Win Win situation.