An infrared camera has a special lens that detects the infrared energy emitted from an object, transforms the amount of infrared energy into temperature, and displays the object as an infrared or thermographic image.
By proper use of an infrared camera and the proper interpretation of the results, under the correct conditions, a themographer/inspector can identify missing insulation, air gaps and moisture behind walls, ceilings or under floors. Infrared scanning can check in-floor or radiant heating. Infrared can help find missing elements in the house.
Moisture is the biggest enemy for a house. Left undetected, moisture can lead to mould and rot. Water typically appears as cold areas with an infrared camera. But not all cold areas mean that there is water present. All cold areas found are further tested with a moisture meter - if "wet", then there is a moisture concern; if "dry", then there is something else causing the cold spot.
Contrary to what you may see on TV or in movies, infrared cannot “see” through objects. The heat from an object can travel through another object and be seen by an infrared camera. Infrared light can pass through many materials which visible light cannot pass through. The reverse is also true – visible light can pass through some objects but infrared light cannot.
In the two pictures on the right, in visible light, you cannot see the arm inside the plastic garbage bag, but the heat from the arm and hand passes through the plastic and can be detected by an infrared camera. But the heat cannot pass through glass, so in the infrared picture, the man’s body heat cannot pass through his glasses, making them appear dark. (Note: The black background is due to the lower limit temperature range manually set on the camera. All the black area is less than 73.6°F/23°C)
What the eye sees ...
What infrared "sees" ...
Infrared thermography is a method of capturing images based on the heat they emit. Infrared energy is light that is not visible to the naked eye due to the length of its wavelength. It is part of the electromagnetic spectrum that we perceive as heat. In the infrared world, everything with a temperature above absolute zero (-273°C) emits heat. The higher the objects temperature, the greater the infrared radiation emitted.
Below are some items that were readily seen with the use of an infrared camera.