The picture on the left shows an "angled ceiling area" in the upstairs bedroom of a 1 1/2 story bungalow.   These "angled ceiling areas" were not visible from the attic.   As you can see on the thermal image (on the right), there is missing insulation in all of these "angled ceiling" areas.  The darker, purple area shown on the thermal image shows a much cooler surface temperature, which is exactly the type of thing we investigate further.  In this case "missing insulation".  Over the course of ownership, this small find alone can easily save you hundreds in future energy costs.