Thermal imaging in a home inspection: what it can and can't show
Infrared cameras are now common in home inspections. Here's what they actually detect, where they help most, and why interpretation matters.
How thermal imaging works
Everything gives off infrared energy. A thermal camera turns that energy into an image where colours represent surface temperatures. When something behind a surface changes how heat moves — a wet patch, a gap in insulation, a draft — it can show up as a temperature pattern on the surface.
Short answer: a thermal (infrared) camera measures surface temperature, not what's inside a wall. In a home inspection it helps find patterns that suggest moisture, missing insulation, air leakage or overheating electrical components — which are then checked with other tools, such as a moisture meter. It cannot see through walls, and results depend on weather, materials and how the home is operating.
What it can help find
- Possible moisture: evaporating water cools surfaces, so damp areas often appear cooler. We confirm with a moisture meter.
- Missing or settled insulation: in cold weather, under-insulated areas on exterior walls and ceilings appear colder from inside.
- Air leakage: streaks around windows, doors, baseboards and attic hatches.
- Electrical hot spots: unusually warm breakers or connections can indicate a problem worth an electrician's evaluation.
- Heating issues: uneven radiant floor or duct heating patterns.
What thermal imaging can't do
- It can't see through walls or show concealed damage directly.
- It can't confirm mould, rot or the exact source of a leak on its own.
- Reflections, sunlight, recent rain and shiny surfaces can create misleading images.
- It's not an energy audit — an EnerGuide evaluation with a blower-door test is a separate service by a registered energy advisor.
Why conditions matter
Insulation and air-leakage patterns show best when there's a meaningful temperature difference between inside and outside — that's why interior thermal surveys are normally done in the heating season (roughly October to April in the GTA). Moisture patterns depend on whether the area is actively wet. A good report records the conditions at the time of the scan and its limitations.
A camera vs. a trained thermographer
Many inspectors now carry a thermal camera. The difference is interpretation: knowing when conditions support a meaningful result, telling a real anomaly from a reflection, confirming with other tools, and explaining limits honestly. Jit Makim holds Level I Infrared Building Surveyor training from the Professional Infrared Training Institute.
At JBM Inspect, thermal imaging is included in every home inspection. Our Signature package adds systematic room-by-room screening, and we offer standalone thermal and moisture services for homeowners from $249 + HST.
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