What is Infrared Diagnostic Testing?

One of the key components of an effective home energy audit is infrared thermography. Infrared thermography (or infrared imaging, infrared diagnostics, IR, etc.) consists of a thorough visual inspection of a home, including the basement/crawl space, attic and all the nooks and crannies with an infrared camera.  It helps take the guess-work out of pinpointing the drafts and the leaky spots within a home by registering the relative temperatures of various spots within the home and providing the homeowner with a visual representation of opportunities to improve the home's thermal envelope. So if you order a Level II or III audit and, after the energy audit, you forget where exactly it was you were supposed to caulk, you've got a big group of images to show you exactly what spots need air sealing or insulation work.

 The top image shows hot air coming in, around and through an attic door.  Not what you want to see in the middle of the summer!

The second image shows a patch of moisture from a broken window in the wall of a house under construction.  This moisture was not apparent visually.

Infrared is a very useful (and super fun) tool although it's important to understand what it can and cannot do.  An infrared image is a record of surface temperatures.  Infrared cannot see through walls, but it will record the temperature of the surface of the wall; if something warm is right behind a wall, some of that heat will conduct through the wall to the surface and be recorded in an infrared image.

The color palette used in these images shows cooler temperatures as blues and warmer temperatures as yellows and oranges.  Looking at the scale on the bottom will tell you what is warm and what is cool.

Infrared is an important tool for energy audits and we use it for every audit.  The IR imager allows us to see air leakage, moisture issues and problems with insulation that would be difficult (or impossible) to see otherwise. Also there can be some big surprises and that's part of what makes infrared imaging so valuable - you might discover that the constant draft in your living room is from air getting in from around the edge of the chimney and not the windows as you thought.  And that's much less expensive to fix!

It's important that the person operating the imager have a thorough understanding of how to take and interpret IR images; without proper training and with certain circumstances, images can easily be misinterpreted.  We have a Level 1 thermographer on staff who has had extensive training in taking and interpreting infrared images with specific emphasis on buildings.

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