glass VS plexiglass

[swords]

In regards to repelling heat from lights I'm curious if any of you have studied whether lamps over glass heat up the terrarium more than lamps over plexiglass?

Over my new terarrium (basically now relegated to a holding tank for "must have" plants until I get the big wall unit built) I bought a simple pane of glass from home depot instead of the plexiglass I used to use on my old Nepenthes terarriums. It seems like the temps are about 5*F hotter when using this glass and not plexiglass. I'm building a bookshelf ths weekend for my plant books so I'm gonna get a sheet of plexiglass and test my theory but I thought I'd mention it and see if any of you have noticed this too.