Inspection pricing: 2026 brackets
- Up to 50 kWp (residential rooftop) - 600-900 PLN net. 2-3 hour inspection, 1 pilot, 1 drone DJI Matrice 30T or Mavic 3T.
- 50-500 kWp (commercial rooftop) - 1,500-3,200 PLN net. Half-day, coverage of up to 1,500 modules.
- 500 kWp to 5 MWp (small ground-mount farm) - 4,500-9,000 PLN net. 1 working day, RTK for georeferencing.
- 5-20 MWp (medium-to-large farm) - 12,000-28,000 PLN net. 2-3 days, multi-drone with a 3-person team and a ground crew for cleaning swab samples.
- Above 20 MWp - project-mode engagement, typically 4-7 days and a custom quote from 35,000 PLN net.
When inspection actually pays back: 4 cases
- Warranty audit. Most PV insurers (Talanx, Allianz, Generali) require an annual thermal inspection for the first 5 years of the farm's life. Without an audit-grade PDF, the insurer will not pay out on a production loss.
- After hail, a storm or a hurricane. Microcracks in panel glass are invisible to the naked eye, but produce a hot spot of 15-25°C within 48-72 hours after the event.
- Before selling a farm (M&A). Buyer-side due diligence almost always requires a fresh thermal image no older than 6 months. Refusing an inspection is a red flag for the investment committee.
- When production drops by more than 3-5%. In 70% of cases, the cause is 2-3 faulty bypass diodes in the inverter or an underground DC cable joint fault.
Technical requirements for inspection under IEC TS 62446-3
- Thermal camera: resolution of at least 640x512 px. A 320x240 px resolution has not been accepted by most Polish insurers since 2024.
- Sensitivity of NETD at most 50 mK at a sensor temperature of 30°C.
- Spectral range 8-14 μm, absolute error of ±2 K.
- Irradiance during inspection - at least 600 W/m² in the plane of the panel. In Poland this is realistic from March to October, in the 10:00-14:00 window.
- Flight altitude above the panels - 25-50 m. This yields about 2 px/cm on a 640x512 sensor - meeting the 3 cm/px standard at the module edge.
- Flight speed of 4-6 m/s (walking pace). Faster - motion blur appears in the long-exposure thermal frame.
What the PDF report must contain: a 9-point checklist
- Farm coordinates in WGS-84 and PL-2000 for the client's geographic information systems.
- A farm map with row, string and inverter markings - the source of truth for the ground team.
- A thermal map overlaid on a normal RGB photo. This lets the auditor see exactly which panel is involved.
- Defect classification under IEC TS 62446-3: hot cell, bypass diode failure, multi-cell PID, soiling, vegetation shading, connector overheat.
- GPS coordinates for every hot spot, accurate to 30 cm (RTK), so the technician finds the location without asking around.
- Recommendations: replace, clean, monitor at next inspection. Each defect carries a priority of 1-3.
- Comparison with the previous inspection - delta in hot spots, PID progression rate, 12-month trends.
- Weather data at the time of capture: solar irradiance, ambient temperature, wind speed, cloud cover - all from a local weather station.
- Operator STS-01 certificate, camera class, last calibration date for FLIR or DJI.
5 common defects and their visual signatures
- Hot cell - a single cell running 15-30°C hotter. Cause: a hail-induced microcrack or a bypass diode failure.
- Multi-cell hot pattern - 2-3 cells in a row. Cause: PID (potential induced degradation), typical on modules older than 5 years with negative-grounded earthing.
- Bypass diode short-circuit - a full third of the panel is hot, a 20-40°C delta. Replacing the diode in the junction box costs 80-120 PLN per panel.
- Soiling pattern - dirt, dust, bird droppings. Not a panel defect, resolved by cleaning at 2-4 PLN per panel.
- Shadow and vegetation - not a defect, but cuts output by 3-15%. Recommendation: trim vegetation or re-plan the strings.
Inspection calendar for a PV farm
- First 2 years - annually (manufacturer warranty period for Trina, Jinko or Longi panels).
- Years 3-10 - every 2-3 years, plus urgent inspections after hail or an extreme storm.
- Year 10 onwards - annually: panel degradation grows from 0.5%/year to 0.8-1.2%/year.
- After any extreme weather event - within 30 days, a requirement under almost every insurance policy.
Without a thermal inspection you pay for the repair after the inverter has already reported a 5-7% production drop. With an inspection - before the drop. The cost gap between one field crew and replacing five panels is 3-5x in favour of prevention.
Frequently asked questions
- Can you inspect the farm without disconnecting it from the grid?
- Yes. For correct thermal contrast the farm must operate at no less than 60% of its rated load. This is an IEC TS 62446-3 requirement: without a working load the hot spot is invisible. Disconnection is unnecessary and counterproductive.
- What if we already have a report from another operator - can you produce a comparison?
- Yes. If the previous report follows the IEC TS 62446-3 format with hot-spot coordinates, we use it as a baseline and in the new PDF we flag the delta: which defects have progressed, which have appeared and which have been closed. The extra fee for the comparison is 400-600 PLN net depending on farm size.
- Which months are best for thermal inspection in Poland?
- From late March to mid-October, in the 10:00-14:00 window under clear skies. December through February do not work: irradiance is almost always below 600 W/m² and thermal contrast is insufficient to separate a hot spot from ambient. The best months for a high-quality capture are May, June, July and September.
