Hi all,
I figured this august group of knowledgable people could solve a mystery for me.
As I was listening to yet another window salesman's pitch, he mentioned that the coating on the glass would let light pass, but would minimize heating in the summer. Now that made sense to me, but then he followed up by saying that in the winter, it would let the sun help heat the room. I'm familiar with bandpass optical coatings that will reflect IR and pass visible (and if they're good, also block the UV), but not with any that change based on temperature. To work as advertised, I would guess that the lower cutoff would have to be temperature dependant and rise in frequency with temperature.
Having never created one like this myself, I was wondering - is it possible? and if so, what technique creates variable coatings? Sadly, all of mine are stable over a wide range of temperatures. Has my little grey cells become even more disfunctional with age than my wife suspects?
Mark