Infrared thermal imaging is not a part of a general energy audit. However it has its own benefit and could be added to the energy audit if needed. Infrared camera can determine hidden problems related to heat, air or moisture in the house. The inspection though has to be performed by a qualified thermographer who can use the equipment properly and under the right conditions.
All objects above absolute zero (- 273 degrees Celsius) emit infrared heat. Thermography can accurately detect and image very small temperature differences on the wall. However it is not an X-ray and it cannot see beyond the walls or other solid surfaces including glass. As a matter of fact it cannot see beyond the paint layer of the drywall. It can strictly detect the heat emitted by the object. Some materials such as paint, wood, carpet emit heat very well, but shiny metals such as brass, aluminum and steel do not. In fact these materials and smooth surfaces reflect infrared. A thermographer must know how to deal with these materials, understand the complexities of heat transfer and be able to analyze the significance of the very small temperature differences being captured by the camera.
Thermography is not just about using an IR camera. Many people falsely believe that thermography is as easy as using a digital camera. The cameras are indeed easy to use but because they image only the surface temperature and not what is behind the surface, interpreting the image must be performed by a trained thermographer,. who understands thermodynamics, material properties and the right conditions for detection.
A trained thermographer, using the right camera, under the right conditions with the right procedure may be able to detect the following problems:
It is not always possible to detect all of the above potential problems at the same time because the conditions may not be right all at the same time for the detection. Insulation inspection requires a temperature difference across the wall. Air leakage detection requires a pressure difference. Moisture detection requires low relative humidity or change in temperature. A proper electrical inspection requires a significant load on the circuits. And the most importantly all of the above requires an extensive thermographer’s training, knowledge and experience to determine what conditions are right.