Infrared Thermal Imaging
Thermography is a detection and imaging of thermal infrared energy. All objects emit some amount of infrared heat. The higher the surface temperature, the more infrared energy is emitted. Thermography can often accurately detect and image very small (0.05 Deg.C) temperature differences on a wall. But infrared thermal imaging is not an X-Ray. It cannot pass through walls or other solid objects, including glass.
Some materials, such as paint, wood, carpet and plastic emit infrared very well. Others such as shiny metallic surfaces do not. In fact these materials and many smooth surfaces such as glass and ceramic may reflect infrared.
An experienced thermographer should understand the complexities of heat transfer behind the wall to the surface, know how to deal with reflective materials and be able to analyze the significance of very small surface temperature differences being imaged by the camera.
A decent infrared camera is an expensive piece of equipment, however the best camera will be useless without properly trained thermographer. Unfortunately many people buy cheap cameras and without proper training start pointing them at various objects not really understanding what they are looking for.The interpreting of the image must be performed by a trained professional who understands thermodynamics, material properties and the right conditions for detection.
With the help of thermal camera under the right conditions with the right procedure the experienced thermographer may detect the following problems:
- Moisture behind a surface
- Leaks in air ducts or plumbing
- Missing or damaged insulation
- Problems with radiant heating
- Unexpected air leaks from exterior
- Furnace, AC and blower motor problems
- Abnormal heat from an appliance or electrical system
- Unwanted animals in the attic and crawl space
- Problems with sealed windows
- Structural problems, such as missing or damaged studs
For the problems related to air leakage thermographic scans are best combined with the Blower Door test. This is another expensive piece of equipment that not every home inspector has. For proper air leakage detection with the thermal camera there should be temperature difference as well as pressure difference. Exhaust fans in the house are not powerful enough to create the required pressure differential. Therefore the use of the Blower Door is essential.
Infrared thermal imaging is extremely useful in commercial inspections of flat roofs. Infrared cameras can detect heat associated with moisture trapped in flat roof insulation. This trapped moisture can result in collateral damage due to roof leaks, costly roof repairs, premature roof replacement, increased energy costs and safety issues related to structural collapse and/or deck failure.
In order to understand and correctly interpret thermographic images a good thermographer requires appropriate education and experience. When choosing an inspector for your thermal imaging needs please remember that this is not the camera but the person who is responsible for correct detection and diagnostics of the thermal patterns.