"Richard J Kinch" wrote in message
. ..

Adding insulation is not typically an improvement in anything of recent
construction. That's a fantasy factoid lingering from the 1970s energy
crisis, endlessly repeated by people who've never measured the realized
benefit.

Richard - Unfortunately our boat is not of recent construction. The original
icebox had just 1/2" of polyurethane insulation. When I installed the refrig
unit, I added as much as I could on the outside. But, it is still not as
much as is often recommended. Only way of adding more, is on the inside.
But, if it won't make much difference in compressor run time, I would prefer
not to do this because of cost of so-called "space-age" insulation or space
taken by conventional insulation.

Perhaps this explains why I would like to measure present power usage, then
add temporary sheets of foam using 2-way tape and measure again.

Thanks for all the input so far guys!

GBM