When to carry out a thermal inspection? Timing makes the measurement
The same installation, the same camera, the same pilot — and yet a usable or a worthless result, depending on the moment. In thermography, timing is not a detail: it makes or breaks the measurement.
Why does this matter?
Thermography does not measure temperature as such, but temperature differences — the delta-T between a defect and its surroundings. If that difference isn't there, there is nothing to see, however good the camera. The right conditions create exactly that difference, and they differ by inspection type.
How does this work in practice?
For solar panels you measure with enough irradiance, ideally above 600 W/m², on a clear day around midday, with the panels under load. Faulty cells then heat up enough to stand out as hotspots. For the building envelope (roofs, facades, insulation) you reverse the logic: you need a large difference between inside and outside, so rather in the cold season with heating on, and preferably at sunset or early morning to avoid stored solar heat. Dry weather, little wind and stable cloud cover make the measurement reliable.
Common mistakes
- Measuring PV in cloud or low sun. Too little load, so defects stay cold.
- Measuring a roof or facade in summer or full sun. The solar load masks the insulation faults.
- Measuring just after rain. Evaporating moisture cools the surface unevenly and distorts the image.
- Ignoring wind. Strong wind cools surfaces and shrinks the delta-T.
Why with a drone?
A drone lets you act quickly when conditions are right: you measure an entire installation within the same weather and light window, instead of spending hours crawling over a roof while conditions change. That keeps the whole measurement consistent.
Why Droneview?
Droneview deliberately plans each flight for the right conditions — irradiance and load for PV, delta-T and timing for the envelope — so the measurement is correct rather than lucky.
Frequently asked questions
What is delta-T in a thermal inspection?
Delta-T is the temperature difference between a defect and its surroundings (or between inside and outside). Thermography measures exactly that difference; if it is too small, there is nothing to see.
Can I have my solar panels measured on a cloudy day?
Preferably not. Panels must be sufficiently under load; with too little irradiance (ideally above 600 W/m²) faulty cells don't heat up enough to show as hotspots.
When is it best to measure a roof or facade for insulation faults?
During a large temperature difference between inside and outside — so rather in the cold season, and preferably at sunset or early morning to avoid the influence of direct sun.
Does the season matter?
Yes. PV inspections need sun and load (spring to autumn, clear day); building-envelope inspections need a cold period with heating on. The timing is chosen per target.
Want to be sure the measurement is right?
We plan your inspection at the right time and under the right conditions.
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