I recently followed the advice of several writers and bought some
insulation.  I purchases the foil type with air bubbles in the middle.  It
seemed like an easy thing to work with (and it is) and I had previously
used it to wrap our cooler.  I measured the widows (the canvas will come
later) and cut with some excess.  I want to just stuff the insulation
against the windows and hope that the excess will serve to keep it fitting
tightly.  The goal was to get ready for cool weather camping.  Last weekend
we went camping, and I forgot to take the insulation sheets out.  Glad I
forgot.  While parking our EVC in the sun, I decided to give the insulation
a try.  They fitted well; easy to install, and did not fall out of
position.  Came back  a few hours later and found the interior not at all
hotter than outside, which was probably in the '70s.  Then after returning
home I went on an errand and parked in the sun, with just the front of the
car facing the sun.  The fridge was off, and its door open, but the
thermometer probe was still inside.  After parking in the sun for a couple
of hours with an outside temperature of perhaps 80 degrees Fahrenheit, I
returned to find that the inside of the fridge/car was 110 degrees.  With
no insulation in the windows the EVC did get hotter inside than outside,
which we've all known, but which I had never documented with a thermometer.
 So I'm going to use my 'winter' insulation all year long.  Jim.
Jim McCarthy
ex '87 Westfalia
'95 EuroVanCamper
Somerville, MA