Moisture in building envelopes can have serious consequences. For example, moisture in insulation reduces its insulating capability, causing heating and/or cooling losses and wasting energy. Moisture can also cause structural deterioration and foster mold growth. Thermal imaging is well suited to identifying wet spots.
Conventional wisdom would have you concentrate thermal imaging on windows and doors. However, windows and doors contribute very little to total air leakage in most dwellings. In fact, the most serious leaks occur at the top and bottom of the conditioned building envelope - in attics and basements.