slunra
Solar performance diagnostics

The sun did its job today.
Did your panels?

We compare your system's real output with what it should produce given the actual weather at your location — and tell you straight whether something's wrong. Not a chart to decode, but a clear answer.

Free · no sign-up · instant result

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Your system · Dražíčmedium confidence
No apparent problem
10,690kWh / year114 %of expected
JFMAMJJASOND
ActualExpected (PVGIS)
8.3 kWp · south · 38° tilt · running since 2/2024
Expected output for your location, adjusted for panel age.
What we compare against

Your numbers against what the roof can actually give

We don't guess. We compare real output against the PVGIS model — a public European calculation (EC Joint Research Centre) that, for your exact location, panel tilt and orientation, factors in the actual weather. The gap between those two numbers is the basis of every verdict.

Actual
What your system really produced
10,690 kWh
Expected · PVGIS
What it should give for the location, tilt, orientation and real weather
9,415 kWh
Verdict
114 % of expected — no apparent problem
Healthy
What we look at

We check as much as we can — honestly, based on what we know about your system

From a hand-entered number we can do one thing. From a connected inverter we read every day, we see much deeper — down to individual panels.

From the quick checkmanual entry

Just location, power, and annual or monthly output.

Long-term underperformanceOutput persistently lower than the location should give — a fault, shading, or a misconfiguration.
Production outageA month with almost no output where there shouldn't be — a sign of inverter failure.
Seasonal anomaliesSuspiciously weak months outside winter — with tolerance for weather variation.
Orientation and shadingRecognises when lower output is down to a legitimate roof orientation, not a fault.
Panel degradationFairly accounts for natural ageing — doesn't do old systems an injustice.
Input qualityIf something's missing, we say so and lower the confidence — we don't fill in gaps for you.

Plus from a connected inverterdaily data

Connect once, then Slunora reads on its own. Deeper findings are rolling out gradually.

Individual panels (strings)Tracks each DC input separately — spots a dead or weak panel that vanishes in the total number.
Self-consumption and exportHow much you use directly and how much you send to the grid — where the value of your output leaks away.
Battery healthCharging, discharging and storage state over time — whether the battery does what it should.
Monthly trends over timeThe verdict sharpens: a rough estimate right away, a monthly view after weeks, a full annual verdict after a year.

Monitoring shows numbers.
Slunora gives a diagnosis.

Tracking apps bury you in charts and leave the conclusion to you. We take the last step — a clear verdict, the evidence behind it, and what to do next. You get charts too, but as a complement, not homework.

Check my system
Monitoringchart · chart · chart · ?
Slunora✓ 114 % — healthy
Confidencemedium → grows with data
Nextnothing to fix, keep watching
Our principle

We never claim more than the data supports

Missing input? We say so

Without a key value we won't label the result, but we don't fill it in or replace it with zero. We'd rather say “we don't know” than give false certainty.

A confidence level on everything

Every finding has evidence and a confidence — high, medium, low. The verdict matches the input quality, not the marketing.

A range, not an invented number

Economic estimates always come as a range with stated assumptions — never a single precise number we can't stand behind.