Aerial Thermal Imaging and What It Finds

A thermal camera does not see heat the way a regular camera sees light. It measures infrared energy leaving a surface and converts it to an image. What that image reveals is temperature difference, and temperature difference is a proxy for something underneath that you cannot see directly.

That distinction matters because it explains both what this technique is good at and why the timing of the flight decides whether it works at all.

Radiometric, not a picture of one

There are two very different things sold as thermal imagery.

A thermal photograph is a colored image. It looks convincing and it is nearly useless for analysis, because the color scale was set by whatever else was in the frame. You cannot pull a number off it.

A radiometric file stores a temperature value for every pixel. Anyone who opens it can point at a spot and read the temperature, adjust the scale, and re-analyze the data independently. That is what makes a finding defensible rather than an assertion.

Every thermal survey we deliver includes the radiometric files. Your engineer, your roofer, or your warranty provider can verify a finding rather than taking our word for it.

Roof moisture surveys

This is the most common application and the one where timing is everything.

Wet insulation holds heat longer than dry insulation. During the day, the whole roof absorbs solar energy. After sunset, the dry areas cool quickly while saturated areas stay warm, and for a window of a few hours the wet zones glow clearly in thermal.

Fly the same roof at noon and you see sun load and nothing useful. This is why roof surveys are scheduled after dark, and why a provider who offers a midday roof scan is either inexperienced or not telling you something.

What it finds: trapped moisture in the insulation layer, saturated areas around penetrations and drains, failed seams, and the extent of damage after a storm. What it gives you is a map of where the wet areas are, which turns a full tear-off question into a scoped repair.

Conditions that defeat it: standing water on the surface, rain within the previous day or so, high wind stripping the thermal signature, and roof assemblies where the insulation is not in contact with the deck.

Solar array inspection

Photovoltaic arrays are inspected under load, in full irradiance, which is the opposite timing from a roof.

A cell that is failing, shaded, cracked, or disconnected does not convert light into electricity. That energy becomes heat instead, and the defect shows up as a hot spot in a pattern that identifies what is wrong.

• A single hot cell typically means a crack or a defective cell
• A hot bypass diode substring points to a diode or wiring fault
• A whole panel running warm usually means a connection problem
• An entire string offline shows as uniform difference across a run

Findings are tied to the array string and panel position so the O&M crew knows where to go, rather than being handed a pretty picture of the field.

For large sites the thermal capture is stitched into a map of the whole array, which makes the pattern of failures visible in a way panel-by-panel inspection does not.

Building envelope and electrical

Envelope. Missing or displaced insulation, air leakage at joints and penetrations, and thermal bridging. Best surveyed when there is a meaningful temperature difference between inside and outside, which in Southern California limits the useful window more than it does in colder climates.

Electrical. Overheating connections, unbalanced loads, and failing components at service equipment and outdoor gear. Aerial thermal is useful for standoff survey of equipment that is awkward or unsafe to approach.

What thermal cannot tell you

Worth stating plainly, because thermal imagery is persuasive in a way that outruns what it actually proves.

• It does not identify a material. A warm area is a warm area. What is causing it is an interpretation.
• It does not see inside a wall. It sees the surface, and infers what is behind it from how that surface behaves.
• It cannot see through glass, water, or most coatings. Those surfaces reflect infrared rather than transmitting it.
• It does not measure moisture content. It shows thermal anomalies consistent with moisture. Confirming it is a core sample or a moisture meter.
• A finding is not a diagnosis. Anomalies are located, classified, and reported. Deciding what to do about them is the qualified person's call.

What you receive

Scheduling one

Because the thermal window drives the result, scheduling works differently from other aerial work.

Roof surveys are flown after sunset, which usually means the crew arrives in the evening. Solar arrays are flown in the middle of a clear day with the system producing. Envelope work needs a temperature difference, which in this climate often means early morning in the cooler months.

Tell us the building or the site and what you suspect is wrong, and the timing gets set from there. Scope is on the thermal inspection service page and published starting prices are on the pricing page.

Frequently asked questions

Do you provide a certified thermography report?

We provide the radiometric data, the anomaly mapping, and a written findings summary. Where a stamped Level II thermographer report is required, we work alongside your thermographer or can refer one.

Why does a roof scan have to be at night?

Because the effect being measured is differential cooling. During the day the sun heats everything and swamps the signal. After sunset the dry roof cools and the wet areas stay warm, which is the only condition where the difference is readable.

Can you scan a roof right after a storm?

Not immediately. Surface water and recent rain mask the subsurface signal. A day or two of dry weather produces a far more reliable survey.

How large an array can you inspect in one visit?

Commercial rooftop arrays are typically covered in a single visit. Utility-scale sites are flown across multiple days and merged into one deliverable.

Will this tell me whether I need a new roof?

It tells you where the wet areas are and how extensive they are. Whether that means a repair or a replacement is a roofing decision, and the data is what that decision gets made on instead of guesswork.