I'm very interested to see if anyone has actually measured the temps behind
the fridge in hot sun vs. in shade.....and if the reflective covering
material on the outside works to reduce heat inside.

If the reflective cover outside helps...it  would seem logical that it
would also matter what color your van is...i.e. white and silver vans
reflect more heat than maroon or dark blue ones do.

Either way its obvious VW thinks insulation inside helps the
Dometic ...hence the original fiberglass.

Seems anything that helps reduce/remove heat from the behind the fridge
area and the exposed cooling fins is beneficial.

Warren C.