You know on the insulation front, there is only so much to be done with walls that on average are about 2" thick. Same with the roof and floor. Slide walls are even less and by their very nature create "weak" spots in the integrity of the unit's insulation.
I'm sure there are some space age materials out there that could probably bump up the effectiveness of the insulation, but like anything that is "better" I'm also sure it comes at a cost.
Personally I would be happy with most components in my rv. It's the actual assembly where most fall down. They are put together like******plain and simple, and it is not unreasonable to expect quality assembly for the prices being paid, but on the flip side some expectations are a bit on the unreasonable side.
I'm kind of tired of living in a run of the mill 2,100 sq foot house. I wish the housing builders would get off the stick and start building some innovative, high quality, "luxury" homes in the 5,000 sq ft range, that I can actually afford.....
