Depends on what you mean by commercial. Commercial freezer rooms usually
have galvanized sheet steel because it is rugged, cheap and can take abuse.
Commercial refrigerators have stainless interiors because it is rugged and
easier to clean. Neither have anything to do with the insulation. The
insulation is provided by 4 to 8" of urethane or in more modern boxes
isocyanurate foam.

Marine refrigerators used to have stainless liners because it was rugged,
easy to clean and easy to fabricate in custom shapes. Now they have off
white injection molded polystyrene liners because it is rugged, easy to
clean, and cheap. They also add minimally to the insulation value because
they don't conduct as well as steel.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"JAXAshby" wrote in message
...
btw, commercial ice boxes always have an shiny ss liner and/or outside.
It
works, at least in the commercial reefer environment.