Just bear in mind you would likely have nil outside visibility with a thermal solution; the window pane would be heated to some extent and be presented as a blank surface of a given colour.
You know, you're right. I'd forgotten that. In fact it's worse; when you mentioned that, I remembered being told that glass acts like a rather poor mirror to the wavelengths used by thermal imagers. I proved this by dragging out my rifle, which has an ex-military thermal night sight (shhhh!
), and I could actually see myself rather vaguely reflected in the window when trying to look through it. Certainly couldn't see through the window.
Scratch that idea.