On Tue, 8 Feb 2005 22:40:00 -0500, "Ray"
wrote:

Multiwall polycarbonate - the thicker the better.

Built a window gh out of salvaged thermal panes one time.
But we had an all glass house and just changed the ends to twin
wall. Also insulated the gh door with an add on of twin wall and
a shrink to fit plastic. You know, the stuff renters use as
storm windows. It drastically reduced the heat bill. I would
build of triple if I were building. Also put it 1/2 in the
ground with lots of mass (feet not inches) of rock to hold heat
in the winter and moist cool air in the summer.
SuE
http://orchids.legolas.org/gallery/albums.php