If you’ve seen a few renovation shows, you may think that infrared (IR) cameras can see through walls to discover defects. While this is not the case, an infrared camera is still a beneficial tool to have on your home inspection.


To understand how infrared cameras work, you first need to understand the history of infrared (IR) a little. William Herschel first discovered infrared rays in 1800. He used a prism to refract light onto a table. While he was measuring the temperatures of the various colors, he realized that the temperature in a thermometer outside the red light was higher than the temperature inside the light. Upon further study, he concluded that there was infrared energy above the red spectrum. More than 200 years later, we have now taken this knowledge and created cameras that can detect this energy and create a thermal image based on that information.


In simple terms, IR is the energy emitted by objects as a function of their temperature. The higher the temperature, the more energy emitted. Everything in the world emits this energy; however, some things output better than others. To make it more complex, there are also objects in the world that act as reflectors. This is where the limitations of the camera can come into play. First, cameras cannot “see through” objects, but rather detect the surface temperature of objects. A good example is wall frame members that can be seen with the camera because they heat or cool differently than insulation. If the insulation and studs are the same temperature, then they cannot be seen. Also, the camera cannot see the water inside a wall; however, it can detect the difference in temperature caused by the evaporation of that water. The camera also cannot see through objects such as windows, nor can it tell the actual temperature of shiny metals or other reflective objects. This is because they have a very low emission and prefer to reflect the energy of the environment than emit their own.

Another major limitation of an infrared camera is the environmental conditions during inspection. The ideal conditions for an infrared camera would be a windless day, no sun, an outside temperature 10 ° Celsius higher or lower than the inside temperature, and when it had rained a few days before the inspection. As you can see, perfect conditions are almost impossible to achieve.


So you may be wondering, “If infrared cannot be used to see through my walls and has environmental limitations, what good is it for my home?” While an infrared camera is limited, it can improve the chances of detecting deficiencies that would not have been found otherwise. It will assist the inspector in hard-to-reach areas such as raised ceilings or attics. It can show moisture leaks or seeps where there are no stains on the walls. Other deficiencies that a thermal camera can detect include (but are not limited to):

  • Foundation water leaks

  • Shower cubicle leaks

  • Moisture intrusion

  • Inadequate or missing insulation

  • Air leaks

  • Duct leaks

  • Electric problems