Spot radiometers and thermal line scanners do not provide the necessary detail for a complete home energy assessment. The most accurate thermographic inspection device is a thermal imaging camera, which produces a 2-dimensional thermal picture of an area showing heat leakage. This process shows temperature variations along the line. The thermogram shows the line scan superimposed over a picture of the panned area. The auditor pans the area with the device and notes the differences in temperature.Ī thermal line scanner shows radiant temperature viewed along a line. It measures radiation one spot at a time, with a simple meter reading showing the temperature of a given spot. The energy assessor may use one of several types of infrared sensing devices in an on-site inspection.Ī spot radiometer (also called a point radiometer) is the simplest. Types of Thermographic Inspection Devices A thermographic scan performed by a certified technician is usually accurate enough to use as documentation in court proceedings.
You may wish to include a clause in the contract requiring a thermographic scan of the house. In addition to using thermography during an energy assessment, you should have a scan done before purchasing a house even new houses can have defects in their thermal envelopes. Because wet insulation conducts heat faster than dry insulation, thermographic scans of roofs can often detect roof leaks. The resulting thermograms help assessors determine whether a building needs insulation and where in the building it should go. Infrared scanning allows energy assessors to check the effectiveness of insulation in a building's construction. Energy assessors use thermography as a tool to help detect heat losses and air leakage in building envelopes. Thermograms of mechanical systems can detect the heat created by excessive friction. Thermograms of electrical systems can detect abnormally hot electrical connections or components. This technology has a number of applications. Thermography uses specially designed infrared video or still cameras to make images (called thermograms) that show surface heat variations. Such air leaks appear as black streaks in the infrared camera's viewfinder. The blower door helps exaggerate air leaking through defects in the building shell.
Thermographic scans are also commonly used with a blower door test running. Because of this difficulty, interior surveys are generally more accurate because they benefit from reduced air movement. Also, it is harder to detect temperature differences on the outside surface of the building during windy weather. Heat loss detected in one area of the outside wall might originate at some other location on the inside of the wall. Interior scans are more common, because warm air escaping from a building does not always move through the walls in a straight line. The energy assessor decides which method would give the best results under certain weather conditions. They also serve as a quality control tool, to ensure that insulation has been installed correctly.Ī thermographic inspection is either an interior or exterior survey.
The resulting images help the auditor determine whether insulation is needed. Images on the video or film record the temperature variations of the building's skin, ranging from white for warm regions to black for cooler areas.
These tools see light that is in the heat spectrum. Thermography measures surface temperatures by using infrared video and still cameras. Energy auditors may use thermography - or infrared scanning - to detect thermal defects and air leakage in building envelopes.
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