Thermal Imaging and Home Inspections

Thermal Imaging has been around for years, but until relatively recently it hasn’t been used extensively in home inspections. In fact, many home inspectors still do not use thermal imaging while performing residential inspections. I would like to demonstrate the benefits and effectiveness of this valuable tool.

Heat Loss

Generally speaking, experienced home inspectors can identify areas of concern related to


missing insulation and energy loss without the use of a Thermal Imager, however this tool is effective in demonstrating the importance to the client as seen in the photo to the left. This can light was replaced and the insulation was not re-installed in an even layer. This would likely result in warm indoor air entering the attic space during periods of cold weather. This moisture laden air would then condense resulting in moisture damage, possible mold, and deterioration of the roof sheathing. When inspecting in southern Wisconsin this is a common defect, in many homes mold is present, rusty nails,


and obvious moisture staining. Of course, an adequate attic ventilation system is also necessary to prevent mold and moisture issues in the attic space. Another common defect is the lack of air flow from the soffit venting. Most commonly, if baffles were installed, this would eliminate this issue entirely. Examining your insulation levels and soffit vent locations for an air channel is a good idea to prevent moisture problems.

Moisture Intrusion

Another area where I find hidden defects deals with moisture intrusion. Since I am not


allowed to open up walls, thermal imaging allows me to check for differences in surface temperature, many times this reveals areas of moisture intrusion, especially in finished basement areas. On one occasion near Monroe, Wisconsin, I was able to identify significant foundation wall seepage behind drywall-finished walls. This would have likely been missed without the use of a thermal camera. While temperature anomalies are not always caused by moisture, these areas are always tested with moisture sensing equipment to verify the presence of moisture should the area be accessible at the time of inspection.

On another occasion while inspecting a small home near Janesville, Wisconsin and did my thermal scan. Excessive temperature differences were indicated by the fireplace. After


testing with my moisture meter, the area was soaked. 98% moisture content. When I was in the attic I did not see any indication of moisture at the vent flashing, and the sheathing and structural members looked fine. Also, the roof was not accessible due to snow cover so the flashing was not viewed. It was determined that the area near the flue lacked adequate insulation, warm indoor air was condensing on the metal flue causing moisture damage. This was another instance that this defect may have been overlooked, had it not been for the infrared camera.

Thermal imaging is a handy tool in identifying these areas of concern, however, it has its limitations. The conditions must be right. The Delta T (the difference between indoor and outdoor temperature) must be at minimum 10-15 degrees to be effective. Although, if these differences aren’t met, thermal imaging is still a effective tool in locating plumbing leaks.

In summary, the use of thermal imaging has helped save our clients thousands of dollars in repair costs as these items were caught during real estate transactions. If your inspector is not using thermal imaging, you may not be getting the complete picture.


Aaron M. Zuehlke is the owner and inspector at Zuehlke Inspection Service, LLC, a full-service home inspection company serving Southern Wisconsin. Specializing in Home inspection, Radon Testing and Residential Thermal Imaging.

If you have a home inspection or home maintenance related topic you’d like to read about please send your suggestion to me via email at

1 thought on “Thermal Imaging and Home Inspections

  1. I have a vacation home in Jefferson County that’s been there for a few years now, and since a storm hit the area recently, I’m worried that the roof might have sustained some damage from the strong rain and wind. It’s great that you mentioned how helpful thermal cameras are with moisture intrusion since the temperature anomalies they detect can help determine the presence of moisture. I’ll keep this in mind while I look for a damage contractor in Jefferson County to hire for an infrared roof moisture scan soon.

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