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What is Thermal Imaging?

By October 19, 2020October 21st, 2020Home Inspection
What is Thermal Imaging

Home inspections are essential when you are making the largest purchase in your lifetime.  However, we cannot see everything with the naked eye.  This is where a thermal imaging inspection comes into play.  What is thermal imaging in a home inspection? 

It is the use of an infrared camera (FLIR) to look at areas in the home that might have issues such as moisture intrusion, loss of air and heat, and hot spots (referring to electrical issues).  Let’s take a look at why this is important in a home inspection, what is a thermal imaging camera, what the colors show, electrical issues, leaks in ductwork, and why the use of this camera is helpful. 

Hopefully, this will help you decide that thermal imaging is an important service to add-on that can save you money and find problems earlier than later.

Why is Thermal Imaging Important?

Regular home inspections give us only certain information because of what we can/cannot see with just our eyes. Even if there are noticeable moisture spots, it is hard to know what is going on. This is where thermal imaging is important.  Also, one cannot see structural issues that are starting to form, or even electrical issues such as in the circuit breaker or possible overloads. 

For example, would you know if there was missing insulation?  Probably not until it was winter and your house is freezing, or summer and your house is too hot.  Thermal imaging is an added service and highly recommended.

What Is a Thermal Imaging Camera?

A thermal imaging camera helps an inspector find areas of heat escaping out of the home and cold air coming in and vice versa.  It also finds water coming in and leaks, condensation, electrical issues, and missing insulation to name a few.

The images that show up on this camera give the inspector views that he/she can share with the homeowner and discuss further investigations.

FLIR Infrared Camera

This is the Forward Looking Infrared Camera (FLIR) used for thermal imaging home inspections.  The FLIR camera can find the surface-heat variations and give the inspector an idea that something is going on.

For example, the camera may show there is a stain on a wall. Additionally, it will show that there is moisture inside the wall and where the leak is coming from.  Unfortunately, we don’t know this information without using the IR camera.

Inside or Outside the Home?

The inspection can be conducted from inside or outside the home.  However, in the southern states (like S.C.) where it is warm most of the year, an internal inspection is a better idea. 

This is because the air doesn’t escape out of the home, it goes into the wall first and then escapes.  This might not be picked up from outside the home, especially with the warm temperatures.

What the Colors Show on the Camera

There are various colors that will show on the thermal imaging camera. The brighter colors, such as red, orange, and yellow, signify that more heat is coming out.  The darker colors; blues, purples, and black show that there is less heat and infrared radiation coming out. There are various color pallets depending on the camera and the most common is rainbow, as mentioned above. 

Let’s look at the example below.  This may be showing that there is a lot of heat loss from the sliders and the windows. However, more investigation is needed.  It is possible that the doors and windows are not double-paned so heat is escaping.  To be sure what exactly is happening, further investigations are needed.

Colors show heat could be escaping the home

Finding Electrical Issues With Thermal Imaging

Putting the camera in front of the electrical box is a great place to start.  Take a look at this picture below.  The yellow in the middle shows there may be heat in one of the connections so looking into it a little more is essential.

Electrical Issues
Infrared camera

Ductwork Leaks

If air ducts are leaking, then the air is escaping the home.  The IR camera can check near these areas to see if that is what is happening. A visual inspection may not be able to find this so the camera is essential to pinpointing this issue.


Checking for moisture issues may be better if conducted in the evening.  This is because the house has had a chance to cool down. If the evaporating water is blue or purple, it may be a leak and further investigation is needed. 

Why Consider a Home Inspection with a Thermal Imaging Camera

Besides not being able to see everything with the naked eye, you are also making a large purchase. You should consider this extra service because of what the camera can show is going on in the walls, plumbing, ducts etc. It will save you a lot of money if the issue is found early as you can correct it now before it is too late.

Lastly, have you ever heard of an HVAC and furnace hooked up wrong and they run at the same time?  It does happen!  When the house is built or units are replaced, sometimes they are hooked up incorrectly. 

Can you imagine how hot it can get in the home with both of those running- canceling each other out? It will cause your electric bill to be sky high!  It would also make the home more warm than cold as a furnace can blow out a lot of heat!

Home Inspectors Must Have Training in Thermal Imaging

There are many home inspectors who purchase thermal cameras without any idea on how to use them or what specific colors mean. For example, just because a wall is showing dark blue, does not mean there is a roof leak.

In this case, a home inspector should evaluate further to see if the roof is leaking, or if the A/C is blowing onto the wall. An easy way to check for this is to turn on the heat to see if the wall changes into a red color. Additionally, further inspection is needed in the attic or on the roof to look for signs of leaking.

A home inspector must be trained and have experience with thermal cameras in order to be effective. They should be used as a tool to inspect further and not used as a diagnosing tool.


Thermal imaging cameras have been around for at least 10 years in the home inspection industry. However, very few companies used them as the cameras were very expensive.  Over the years, prices have dropped and inspectors are going through training to use them and using them more often. 

Home inspectors want to provide the best information they can to you about the home.  We can see only certain things with our eyes so this form of technology is essential to help homeowners.  Do you have questions about Thermal Imaging or have you used this add-on service? Leave us a reply below and let us know your thoughts!

The Rivertown Team

Author The Rivertown Team

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