What Thermal Imaging Can (and Can't) Show During a Home Inspection

Thermal imaging is one of the services clients ask about most, and it is easy to see why. The pictures look dramatic, and the idea of seeing inside your walls is appealing. I offer it as a standalone service and as an add-on to a home inspection, so I want to explain honestly what it does well and what it does not do.

How it works

An infrared camera does not see through anything. It measures the surface temperature of whatever it is pointed at and shows the differences as colors. A patch of drywall that is cooler than the wall around it shows up as a different color, even though it looks identical to the eye.

Those temperature differences are clues. On their own they do not prove anything, but they tell me where to look more closely.

What it can help find

• Moisture. Wet materials often read cooler than dry ones because of evaporation. A cool patch on a ceiling below a bathroom, or along the bottom of a basement wall, is worth investigating, and a moisture meter can then confirm whether it is actually wet.
• Missing or uneven insulation. In heating or cooling season, gaps in wall and ceiling insulation show up as warm or cold areas. This is common in older homes and sometimes in new ones too.
• Air leaks. Drafts around windows, doors, attic hatches and outlets can show up clearly, which helps explain rooms that are hard to keep comfortable.
• Electrical hot spots. A breaker, connection or component that is noticeably hotter than similar ones nearby can be a sign of a problem that an electrician should evaluate.

What it cannot do

• It cannot see inside walls. It sees the surface. If a leak has not affected the surface temperature, the camera will not find it.
• It depends on conditions. Thermal imaging works best when there is a real temperature difference between inside and outside. On a mild day, some issues are simply not visible.
• It does not replace a diagnosis. A thermal pattern is a reason to investigate further, not a conclusion. Some patterns turn out to be harmless, like a framing member or a heating duct.

When it is worth adding

Thermal imaging is a good addition when you are buying an older home, a home with a finished basement, or a newer home where you want to check insulation and air sealing. It is also useful as a standalone service if you already own the house and want to track down a draft, a cold room or a suspected leak.

If you want to add it to your inspection, choose it when you get your quote or mention it when you book online.