In one preferred form of the present invention, there is provided a computer implemented thermal audit method (58) including: using items (64) of photograph data (66), each item (64) of photograph data (66) being of a structure from a viewpoint where the item of photograph data (66) is based on the visual spectrum as would be seen by the human eye; using items (74) of thermal image data (76), each item (74) of thermal data (76) being of the structure from a viewpoint where the item (74) of thermal image data (76) is based on the thermal spectrum as would be seen by a thermal imaging camera; and applying a computer algorithm that identifies thermal points of interest (82) in connection with the thermal image data (66) and combines the thermal areas of interest (82) with the photograph data (66).