Given: everything with a temp above absolute zero give of IR. The higher the temp, the more IR. What I am having a hard time understanding is stories where IR is used to see inside buildings to locate targets, and track their movement. Let us take for example a standard home. The exterior walls are typically a half in of stone (drywall), three inches of insulation - usually fiberglass, and an exterior wall of possibly 1/2" clapboard, with maybe a layer of metal or plastic siding. Yet in the stories one is able to not only locate, but track in real tome human and pet locations and motion. to my mind, in order for the IR from a human to be able to be sensed through all that their body would have to be giving off so much IR that they should be dead from heat stoke. I will grant sensing through a pane of glass or clear plastic, but have a hard time accepting tracking motion through standardly constructed outer walls.