Building Thermography
The thermal image, which is effectively a picture of thousands of surface temperature measurements, makeing it easy to see where insulation is missing or air is leaking in or out of a building.
Any object that is not generating or absorbing heat will tend towards the surrounding air temperature, so cold air leaking into a building will show as cold patches on the wall, floor or ceiling. Conversely, warm air leaking from a building will cause warm patches on the outside wall or roof. Thermographic testing alone can be used as a quick method of finding air leaks in a building structure, and can be used alongside air leakage testing which will quantify the leaks.