During an inspection, a large rectangular cold spot was detected, which usually indicates moisture. When it was tested with a moisture meter, however, it didn't register any moisture. The AC was running when this image was taken. On a hunch, we scanned the area again while testing the furnace and it became a hot spot. It turned out that the re-modelers sheetrocked over an air register. 

The thermal camera comes in handy, especially when attic access is limited or obstructed. We can still see voids in the insulation of the ceiling and walls. Voids will show up as hot spots, and you can usally see the outlines of studs or joists. Voids in the insluatoin lead to heat loss and higher energy bills.

Moisture usually shows up as a shapeless blue blob on the thermal camera. In order to verify that there is actual moisture intrusion, the area must be tested with a moisture meter. In this case, a leaking toilet flange on the other side of the wall was causing moisture to build up under the carpet of the adjacent bedroom.