How Important is Double Pane Windows? (Precept 3UL & others)

I've had both and prefer the dual pane windows to the point that it would be a deal breaker on any coach without them. For those that think the windshield is ONLY single pane glass, they are wrong. The windshield is dual pane with a plastic layer laminated in between instead of an air gap. The windshield is also at least twice as thick as a single pane window glass.