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  • Writer's pictureSquare One Inspections

Thermal Imaging During a Home Inspection

Thermal imaging covers a wide range of technology; from a general view showing basic temperature differences to highly sensitive and technical temperature variances to determine the source/reason for the difference. To be clear, apps cannot provide reliable results. A phone adapter or complete camera is the only way to go. We use FLIR products (Forward Looking Infra Red) that were originally designed for the US Navy.

Thermal Imaging is NOT X-Ray Vision

First of all, thermal imaging is simply showing the different surface temperatures, not what is behind the walls. Temperatures are then shown in color. Warm temperatures are yellows, oranges, and reds. Cooler temps are blues, greens and purples. Imagers cannot tell you what is happening on the other side of the wall when a variance is identified. Experience and logic come into play to determine the issue.

Common Finds:

Missing Insulation:

Missing wall insulation is tough to replace, but sometimes knowing if the pockets are small or significant will help understand the future energy needs to heat the home. The blue boxes beneath the cross hairs are showing lack of insulation between wall studs and rafters. To add insulation, a part of the wall would have to be removed.

Insulating an attic access is much easier and can make a significant impact to your annual energy costs. Adding a layer or two of rigid foam insulation can really make a difference. The blue box below the temperature is the attic access hatch, clearly cooler than the area around it (insulated ceiling).

Functioning Heat Sources

One of the first things we do in a home, summer and winter, is turn up the heat to confirm each register is functioning in every room. You'd be surprised how often we find a register, ductwork, or radiant panel that no longer functions (or maybe never did!). A few minutes of time will really help you understand how comfortable each room will be during winter and eliminate an unwanted surprise on the first really cold day.

Forced Air Ductwork

Functioning Register (slowly warming)

Radiant Heat Panel (ceiling, in this case)

Unknown Bath Fan Termination

As reviewed in a previous blog post, bathroom fans should vent outside, not towards the outside. From the attic, a bath fan with ductwork to the exterior looks correct and can be easily overlooked. If you don't see an outside opening for the air to vent, the issue still exists and a future mold problem is still likely. Using a thermal imaging camera can help you confirm this when the soffit (area below the eve) is warmer in the location of the bath fan ducts. Basically, hot air is being blown at the eves. 90% of this air will bounce back and end up in the attic. Notice how bright yellow is above and left of the crosshairs? That's an issue...

Leaking From Above:

Leaks from above are usually due to a roof or plumbing leak. Many leaks occur without causing an impact to the ceiling that lies below them...yet. They will, but enough water hasn't accumulated to become visible with the naked eye. Hence, the thermal imaging camera! In the case below, a toilet was leaking but hadn't shown in the room below. How mad would you be if your new home had a damaging leak a few weeks after you moved in?

Missing or Inadequate Weather Stripping:

A missing weather strip can allow drafts to enter and really cool off a room, particularly if that room is a small entryway or hallway. Improving the weather strip or possibly replacing the door with an improved product will pay for itself through lower energy costs.

We use thermal imaging on every home, summer or winter. Its important to look for issues early . A hidden problem is still a problem. For more information on this and other home and home inspection info, please visit our

Thanks for reading,

Matt and Matt

Square One Home Inspections, LLC

Serving Maine Since 2014

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