There are many things that energy auditors look for to determine the What Is a Thermographic Inspection?
A thermographic inspection is a scanning of a building using infrared cameras or video. These infrared tools detect, measure and record surface temperature of an object or area. The scan can accurately detect problems and often allows homeowners to avoid invasive, destructive, and often costly measures to locate the same issues. This examination relies on the ability to read the heat spectrum. The coldest temperatures in this spectrum will appear as black images and range up to red or even white images for the warmest temperatures. A problem in the building envelope will generally show up as a variation in temperature on the heat spectrum during a scan.
In addition to detecting air leaks and thermal defects, this inspection can also detect areas of moisture which may indicate water leaks. Moisture intrusion can be detected in walls, floors, the ceiling or the roof, and in some cases can locate a leak in the plumbing. An experienced thermographer can help property owners identify issues unseen by the naked eye and hopefully catch water issues before they become serious problems.
Infrared scanning may be performed on the exterior or the interior of the building. For the best results, the inspector aims for at least a 20°F temperature difference between the indoor and outdoor air temperature. If accessible, indoor inspections tend to produce more accurate results. Detection from the inside wall shows clearly where the warm air is escaping. Outdoor scans may not always show where the leak originated, as heat does not always travel in a straight line. Also, outside weather conditions, such as wind, may affect the readability of the inspection.
Energy auditors may perform an initial inspection to determine how tight a building currently is, if insulation is present, and if the insulation is properly installed. These scans can help to reduce existing utility bills as well as determine potential problems before making a home purchase. They may also be conducted after work has been completed on a building to verify that the improvements were correctly installed. An infrared report can be used as official documentation if performed by a certified inspector.
Types of Thermographic Tools
The most commonly used infrared sensing device is the thermal imaging camera. This device can show two-dimensional infrared pictures of areas without leakage and other areas with leakage. Other infrared tools include a spot radiometer, or point radiometer, to measure the temperature of one given spot at a time. A thermal line scanner, on the other hand, shows a line scan of radiant temperature. This device superimposes the scanned image over a picture of the area to show what’s being viewed. These other two options are not generally used for a comprehensive home energy assessment due to lack of sufficient detail.
Is a Blower Door Test Necessary?
The tightness of a building’s envelope is based on many factors, including the building science used in construction, the age of the building, and the building materials. Some buildings may not easily show areas of leakage. Therefore, blower door testing may be implemented simultaneously with the thermographic inspection. A powerful blower door fan blows air into the building thus adding extra air pressure. This additional pressure helps to exaggerate the amount of air that leaks through the thermal defects. The infrared tools can then easily detect the streaks of air escaping the building. Many times it can be seen around any opening in the drywall. Some examples are plumbing fixtures, electric outlets, windows, doors and lighting fixtures.
How to Prepare for an Inspection
When scheduling your inspection, consider that the greater the temperature difference between inside the house and outside, the clearer the readings will be. A temperature difference of 20°F or greater is ideal. In the summertime this may be at the peak of the day when it’s hot outside and the air conditioner is running indoors. In the wintertime this could be early in the morning when it’s coldest outside and the heater is running inside. As previously mentioned, the most precise thermal scan is one conducted on the interior of the building. Therefore, removing any large furniture from the walls or curtains from the windows may assist in getting the most accurate readings.
