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How Inspectors Use Thermal Imaging Cameras

How Inspectors use Thermal Imaging Cameras

Thermal imaging cameras have been in use for 100 years and were first used in wars. Today, thermography cameras are in use for recreation and professional services like home inspections.

Home inspectors frequently use thermography during their home inspection process. But how do they use thermography to find defects?

What Do Thermal Imaging Cameras Do?

To first understand how inspectors use thermography cameras, let’s talk about how they work.

Thermography measures surface temperature. Therefore, a wall (like the featured image of this post) exhibits different colors to show surface temperature differentials.

Thermography CANNOT Detect Moisture

It is a common misconception that thermography cameras can detect moisture inside walls and this is not true.

As stated above, we can only understand surface temperature differentials from the thermal image.

But how do inspectors find water intrusion through thermography? Let’s talk about it.

How Home Inspectors Use Thermography

Home inspectors can use thermal imaging to find:

  • roof leaks
  • plumbing leaks
  • lack of insulation
  • missing registers
  • leaking ductwork
  • moisture intrusion
  • termites
  • and much more.

The uses of thermal imaging is a never ending the list. The reason being? Surface temperatures tell a story about what is happening.

Find out different ways water can enter your home.

Experience and Training

It takes a certain skill to use a Flir or Fluke thermal camera. Home inspectors cannot just buy these things and claim they are experts.

Rather, home inspectors have to complete hours of in-classroom and outside classroom training to fully understand its limitations and capabilities.

Moreover, each thermal camera is different! This only make the process harder for the user. If you are using an extremely powerful thermal imaging camera and you change over to a lower level (cheaper version) then the images can be drastically different.

How to Find Water

So how do home inspectors find water intrusion?

Well, first they understand what is on the other side of the wall or surface they are looking at. Then, they think about possibilities for a thermal anomaly.

A Thermal Anomaly is a thermal image that differs from what is expected.

Next, they conduct further research to confirm their suspicions or request further evaluation.


If I am using a thermal camera at a ceiling and see a cool spot on the ceiling, I immediately think of several causes.

  • Lack of insulation (it’s cold outside)
  • Missing register duct. (blowing cold air)
  • Damaged/leaking ductwork. (blowing cold air)
  • There is condensation from the ductwork or register.
  • There is a roof leak.

From further analysis of the home, we can then narrow down the list. We can crawl in the attic to find the condition of the ductwork, as well as, inspect the roof for damage.

There was a time a home inspector called out a massive roof leak from only looking a thermography camera image. Well, a Realtor (the listing agent) invited the inspector to come and re-inspect since she did not believe it was a roof leak.

What was the cause of the really big blue color on the thermal camera? A register was missing. Once the heat was turned on, that once blue spot turned red and the temperature rose!

Summing Up

Home inspectors can use thermal imaging cameras to find: water intrusion, pests, leaking ducts, condensation, missing insulation, and much more.

A home inspector should be properly trained through classroom education and on the job training in order to use this tool professionally.

If you have any further questions on thermal imaging, comment below!

You can also check out another post on thermal imaging.