What Is Thermography?

Thermography is basically the use of an infrared imaging and measurement camera that can actually "see" and "measure" thermal energy emitted from an object. The camera can only sense the temperature difference that transfers to the most outer surface of a wall, ceiling or floor (and if the Delta T, or temperature difference, cannot conduct this difference to the outer most surface, then my infrared camera is unable sense anything within the surfaces of a building). So it’s very crucial to have a temperature difference of at least ten degrees Fahrenheit between inside and outside temperatures. Most materials that are moist or located inside inaccessible surfaces will have an absolute temperature difference in a seasonal situation due to conditioning the living areas with heat in the winter and A/C in the summer. In New England’s ever-changing weather, the inside and outside temperatures will contain sufficient differential most of the time. If the A/C or heat is not conditioning the home, and the outside temperature is the same as the inside temperature, then the infrared camera can not perform its intended function. Temperature differential is absolutely necessary for me to better interpret the camera images and its indicators.

Now that you understand what Thermography is, I'm going to be more explicit as to “How this technology actually works”. Thermal, or infrared energy, is light that is not visible because its wavelength is too long to be detected by the human eye; it's the part of the electromagnetic spectrum (EM) that we perceive as heat (See electromagnetic spectrum below). Unlike visible light (in the infrared world) everything with a temperature above absolute zero will always emit heat. Even very cold objects (such as ice cubes), will emit infrared images. The higher the object's temperature, the greater the infrared (IR) radiation emitted. By detecting those differentiating thermal patterns that are invisible to the naked eye, I’m able to point out concealed issues that need attention now. These findings enable homeowners to perform repairs in a predictive fashion rather than in a reactive manner, which is going to be far more expensive and time consuming when these invisible issues finally become apparent.

ELECTROMAGNETIC SPECTRUM

Below, you can see that infrared starts where visible leaves off (in the EM spectrum), the color red grades into reflective infrared. This is the infrared energy reflected from the surface of an object.

To imply that infrared cameras are like X-ray machines and enable Thermographers to see through walls and ceilings is ludicrous. By looking at the graph above, you can clearly see that infrared waves are nowhere near the same wave length as an X-ray.