Last weekend I performed a thermal whole-house scan inspection and found many areas in the ceilings that looked like missing insulation.  During the exterior scan I peeked into the crawl space and found a warm area on a duct.  This area is radiating heat into the crawl space.  The important note is a thermal scan can reveal a multitude of potential defects.  I read on a local forum about a home that has experienced over $700 in cooling bills during the summer while neighbors with a similar floor plan are paying less than a third of that.  Upon a visual inspection the owners FINALLY found a duct disconnected.  This could have been found immediately with  thermal infrared scan.