The light we see with our eyes is a very small portion of what is called the "Electromagnetic Spectrum." The Electromagnetic Spectrum includes all types of radiation - from X-rays used in hospitals, to radio waves used for communication and even the microwaves you cook with.

A rainbow shows the optical (visible) portion of the electromagnetic spectrum and the infrared (invisible) portion would be located just beyond the red side of the rainbow.

Although infrared radiation is not visible, humans can sense it - as heat. Put your hand next to a hot oven if you want to experience infrared radiation "first-hand"!  All objects emit infrared radiation as a function of their temperature. Infrared cameras do not see temperatures, they detect thermal radiation.  
 
Infrared thermal imaging has become a useful tool in the detection of electrical anomalies, heat loss, ventilation issues, and air conditioning (HVAC) loss. Infrared cameras measure thermal radiation and show images of anomalies in the electromagnetic spectrum from .7 to 1000 micrometers. A report can then be created (digital and infrared picture and explanation) so the customer will be able to identify the anomalies in the building envelope, i.e., missing insulation, air leakage, electrical concerns, etc.  
 
The U.S. Department of Energy says a huge portion of our energy bill is wasted due to a lack of weather stripping around doors and windows. Insufficient insulation is also to blame. How can you see behind a wall or a ceiling? Who do you call? Try a certified Thermographer with a camera that will show anomalies in your home.  Home inspection is an art of identifying shapes, colors, and images in an infrared picture; primarily looking for a change in pattern rather than concentrating on specific temperature differences.

They say a picture is worth a thousand words... Let's look at a couple of pictures to better understand infrared technology.