Thermal Imaging Doesn't See Through Walls. Here's What It Actually Finds in a San Diego Home.
- Bryan Field
- 6 days ago
- 3 min read
Ask most buyers what an infrared camera does and you'll hear some version of "it sees through walls." It doesn't. What it actually does is read surface temperature — and in a house, temperature differences are usually a symptom of something. Water is cooler than the drywall around it. A gap in the attic insulation shows up as a warm stripe on a hot San Diego afternoon. A loose electrical connection runs hotter than the ones beside it. The camera doesn't diagnose anything on its own. It tells an inspector where to stop and look harder.
That's the honest version, and it's still a genuinely useful tool. Here's where it earns its keep in San Diego County homes.
Moisture you can't see yet. This is the big one. A slow supply-line leak behind a shower wall, a roof leak quietly wetting a ceiling cavity, condensation around an AC air handler — all of it tends to show up as a cool patch long before it shows up as a stain. Catching it early is the difference between a plumbing repair and a plumbing-plus-drywall-plus-mold repair. And when the camera does flag something, the next step is a moisture meter to confirm it, not a guess.
Missing or settled insulation. Inland from Santee to Escondido, attic insulation is most of what stands between you and a brutal August cooling bill. Infrared makes gaps, compressed batts, and spots a previous contractor never put back obvious in seconds — invisible from the hallway, expensive every month.
Electrical connections running hot. Scanning a panel and its circuits under load can reveal a breaker or connection heating up more than its neighbors. That usually means a loose lug or an overloaded circuit, and it's worth knowing about — especially in San Diego's large stock of 1960s–90s homes still running original panels.
Slab leaks. On slab-foundation homes, a warm line tracking across a floor can point to a hot-water line leaking under the concrete. It isn't common, but when it happens, finding it early matters a great deal.
Two things thermal imaging is not. It is not X-ray vision, and it is not a mold test. An infrared camera can show a temperature anomaly consistent with moisture; confirming what's actually growing there takes mold and indoor air quality testing, which is a separate service. Both InterNACHI and ASHI treat infrared as a supplement to a hands-on inspection rather than a replacement for one, and that's exactly how it should be used.
Conditions matter, too. The camera needs a temperature difference to read, which in San Diego means it generally performs better on a hot afternoon or a cool morning than at a flat 70 degrees. A good inspector will tell you what the conditions were rather than implying the scan caught everything.
Used properly, it's one more way to make the report reflect the house as it actually is — not just the parts you can see.
Do home inspectors use thermal imaging?
Some do and some don't. It isn't required by California licensing or by standard inspection practice, so it varies by inspector. Keen Eye uses infrared thermal imaging on inspections throughout San Diego County, alongside the standard hands-on visual inspection.
What does infrared thermal imaging find in a home inspection?
Most often: hidden moisture from plumbing or roof leaks, missing or displaced attic insulation, air leaks in the building envelope, electrical connections running abnormally hot, and occasionally a hot-water slab leak. Strictly speaking it finds temperature anomalies — the inspector interprets them and confirms with other tools.
Is thermal imaging worth it in a home inspection?
It's worth it for what it catches early. A leak found behind a wall before it becomes a mold and drywall project typically pays for the inspection several times over. What it is not is a guarantee that nothing was missed, and any inspector who suggests otherwise is overselling it.
Which San Diego home inspectors offer thermal imaging?
Keen Eye Property Inspections offers infrared thermal imaging on inspections across San Diego County — including La Jolla, El Cajon, Santee, Escondido, Carlsbad, Chula Vista, and Temecula. Call (714) 727-7385 or visit keeneyepropertyinspections.com.
Keen Eye Property Inspections has completed 2,000+ inspections across San Diego County with 94 five-star reviews. Same-day digital photo reports, infrared thermal imaging, and sewer scope inspections ($275) available. Schedule at keeneyepropertyinspections.com or call (714) 727-7385.
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