Our Infrared Audit: Photos of a Leaky House

Infrared Image of the Energy Circle house

"Our house is a very fine house... with cool spots in the eaves..." The thermostat on the right side of this infrared image demonstrates the range of temperatures inside and out. Bottom line - our insulation's insufficient and we are not keeping our heated air inside.  The hot roof near the valley in the center of the photo marks that spot where the ice freezes to make a dam in the winter.

Infrared Image - Living Room Corner

We expected cool spots - along windows and doors, for example. This was a surprise: a really cold spot in the corner of the guest room. If not for the infrared audit, we'd never have known. Now I've caulked that cold corner up with a clear sealant, also invisible to the eye.  All better. (Really!)

Infrared Image - Living Room Window and Joist

More surprises in the living room... cold spots along the beam joist, through a combination of thermal bridging (the result of post and beam architecture) and leaking air.

Infrared Image - Painting, Windows

The view from here: I am standing inside our (warm) living room, with infrared auditor Flemming Lund. The glass over the painting captures our reflection, and the windows get called out by the cold.

Infrared Image - Energy Audit

We aren't alone. Basement woes, like these air leaks around the rim joist, and uninsulated concrete sucking heat out, are pretty common.

Infrared Image - Ceiling

This is the ceiling in our bedroom. You can see streaking air as a result of and old school cold roof structure that completely compromises the insulation cavity.

Infrared Image - Front Door Air Leaks

Our front door, with leaky panels and compromised weather-stripping, isn't doing much to keep the cold out.

Infrared Image - Hot Dog!

Hot dog. Couldn't resist. We had a very cool piece of technology in the house, after all.  (No promises your infrared auditor will think this is entertaining, however). I'm curious though... why the hot legs?

In all seriousness, the audit made me see our house in an entirely new light. It helped me get my Rosie Riveter on, and we've already started to make serious (and dirt cheap) changes to stop wasting conditioned air.


Hi, Great work, nice to spread the word for thermorgraphers. Keep up the great work. Quick Q: Why was an emissivity of 0.91 used? I know it will not change the outcome as your doing a qualitative vs quantitative review - just curious.


Peter Troast's picture


Not sure on the emissivity issue. Have an email in to Flemming Lund, who shot these, and will get back to you.


The emissivity is a setting in the infrared camera to measure the amount of radiation that is emitted from the object compared to that of a perfect blackbody.
Blackbody radiation is a object that absorbs all radiation that impinges on it at any wavelength.

So the setting of 0.91 emissivity is used because it is very close to several types of materials used in the construction of homes. Plaster is 0.91, Paper is from 0.7 to 0.95, concrete is 0.95, glass is 0.97, planed wood is 0.8 to 0.9. So 0.91 is a good average that can be used in many applications and to locate gaps in insulation or to locate cold air infiltration the +- 0.10 does not have any effect.

Making major changes to the emissivity setting will change the temperature detected by the infrared camera, however we mostly use the different in the color display to locate issues in the building envelop.

Good question

Flemming Lund
Infrared Diagnostic LLC

The hot legs on the dog are because the blood vessels are very close to the surface and are not insulated by fur. Note that his surface temperature where there is no fur is in the low 90's, a bit warmer than a human bean. Next time, get a shot of his face because his nose shows up black/cold.

Ed Minch

Your answer to the question is about perfect, Flemming. However, the plus or minus .1 E does make a difference. If you are referring to the image you are correct, but the temperature reading in the camera will change by quite a bit at plus or minus .1 E.

With that being said, for energy analysis one would normally be doing quantitative analysis, which does not entail temperature measurements.

I cannot stress the importance of IR training when using a camera. So many people think it is point and shoot, and that is just not correct.

Are these images taken during a blower door test? Without the assistance of a blower door a structure will show stack effect, wind effects and no where near as good of a signature through the camera.

Jason Kaylor
Level II SNT-TC-1A Thermographier

Peter Troast's picture

Jason--Yes, all the interior IR images were shot while the house was depressurized via the blower door.

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