Infrared Imagery Knowledge

An infrared image shows a gradation of colors from cold blue and purple to hot yellow and white. The color assigned to a particular temperature depends on the full range of temperatures measured in the image view. Therefore, the colors are all relative, and the image shows relatively warmer and colder areas.

The answer is no. The only thing the infrared camera sees is the temperature of the outermost layer on a house, such as the outside layer of glass in a window, the siding or the roof.

When reviewing the results of an infrared survey, it is important to remember that the amount of heat being lost in a problem area is proportional to the size of the problem area, and also is proportional to the intensity of the heat loss. In other words, an entire wall with poor insulation will lose more heat than a small window which is of poor quality.

Windows are likely the most common problem identified. It is common to see windows show up on the survey as red, yellow or even white. Modern high-quality windows will show up as blue, or maybe green. It is also common to see evidence of a lack of sealing around the windows and poor insulation around them.

Doors come in a variety of qualities of heat barriers, much as windows do. Decorative windows within doors are commonly single-pane glass and lose heat. Lack of sealant and insulation are common around doors. Missing weather stripping is also common.

There are a variety of problems that can develop with wall insulation.     In older houses, and some newer ones, there may just have been insufficient insulation to start with. A common problem with older houses is that the insulation can sag, leaving a gap at the top of the wall that has none. Sometimes insulation gets removed during window replacement and is not properly reinstalled. Water infiltrating the walls can cause insulation to sag. Rodents can dig burrows, which heat will follow.

Attic insulation may just be insufficient. Also, rodents can dig burrows which give heat easy pathways to escape. Construction work in the attic space can disrupt the insulation.

This happens when the structural components of a building join in ways that preclude proper insulation. This usually results from the fact that wood is a better conductor of heat than insulation is. Metal stud construction can be even worse. Common places that this occurs is floor-wall connections, wall-wall connections and wall-roof connections. To a lesser extent, it can also be seen each place there is a stud in the wall. This can be remedied by the installation of a thermal barrier.