2 points
I have an IR camera and windows look like mirrors. Might depend on the type of glass idk.
7 points
if this yahoo from the internet I found in a search is right then its both:
“Glass will bock low frequency IR (red hot), but allow the passage of high frequency (white hot) IR. Hence, the heat of the sun will easily pass into a greenhouse, but once this energy is converted into low frequency heat by the objects within that absorb it, then the resulting low frequency heat is trapped. Hence, the Greenhouse Effect.”
3 points
