One key component of a comprehensive energy audit is a thermal or infrared scan. A thermal scan is preformed using a sophisticated (and expensive) camera that can detect subtle changes in temperature. Both the interior and exterior of your home are usually scanned to check for leaks.
A thermal scan is an important diagnostic tool because it allows you to see through the walls, floors, ceilings and roofs of your home making it far easier to identify – and then fix – the cracks and openings in the shell of your building. Thermal inspection is recognized as the fastest and most cost effective way to find energy leaks. Thermal scanning is a proven diagnostic technique recommended by the US Department of Energy for identifying areas of heat loss.
Finding the Leaks
In the image below (provided by Infrared Energy Services, LLC.) a wall and window were scanned (during the winter months). The dark purple shows colder temperatures. With high resolution thermal cameras, trained energy auditors can see the leaks in the building envelope.
In the second picture below, thermal scanning makes it easy to see where cold air (in dark blue) is leaking in from under the window. This room also has air leaks along the entire length of its wall-to-floor junction, making it very drafty.
Here are some more pictures from the field thanks to our friends at Green Guild:
The image to the left shows a leaking air conditioner duct. The cold air (shown in purple) is escaping from the corner where the two ducts meet. The ducts were leaking costly conditioned air right into the hot attic.
The photo to the right shows the cold air (blue) leaking from the air conditioner’s blower mounted in the attic. This was a significant air leak; the connection between the duct work shown in silver/red on the right and the blower frame had a large gap which was not sealed.
The dark blue patch is the cold air leaking out from the gap. This air was blowing so hard that it resulted in a cold spot on the attic roof, causing condensation (and eventually rotting)! The installer had forgotten to apply sealing tape and the homeowner’s energy dollars were paying to cool the attic!
More on Infrared Scanning
During a home energy audit, the auditor may use thermal scanning to determine air leakages in the house and the quality of insulation. However, Jim Lockwood explains in the video below that this test does not always detect all thermal defects. Sometimes, destructive investigation (drilling a test hole inside the house) is necessary to determine if insulation is needed.