Unsound Unsound:
That's really cool. Don't think it would work here though. I think you'd lose too much room insulating it properly.
You would be surprised!
The actual difference between an R7 (1" of modern high end spray foam) and R24 (std batt insulation for 2x6) wall is a lot smaller then people think. Yes, the R# difference is fairly large, but the thermal performance is not.
Couple that with a foam vs batt insulation for reduced convection, and the metal skin to reduce radiant transfer, and these units can insulate just as well as a traditional wall at a significantly reduced wall thickness.
I wouldn't be shocked that these containers hit R24 (or higher), in actual thermal performance, on 2" wall thickness. And they don't stop at 2", most are furred out to 4 1/2" at minimum, as it makes them compatible with standard building components (windows, doors, electrical boxes, plumbing, etc).
I would be far more concerned with the type of windows and doors they use then I would the insulating value of the unit walls.