You will see solar panels advertised with efficiency ratings of 20%, 21%, 22%. But here is what most installers do not tell you: panel efficiency is measured in a laboratory under perfect conditions. What actually matters in Kerala's real weather is something called the Performance Ratio.

What Is Performance Ratio (PR)?

Performance Ratio is the measure of how efficiently your entire solar system converts available sunlight into usable electricity — accounting for all real-world losses. It is expressed as a percentage. PR = Actual energy output ÷ Theoretical maximum output. A system with a PR of 80% means that for every 100 units it theoretically could generate, it actually delivers 80 units to your home.

What Causes the Gap?

  • Temperature losses: Panel surface temperatures can exceed 60°C in Kerala's summer, reducing output by 10–15%.
  • Wiring and connection losses: Small resistance losses across cables and connections, typically 2–3%.
  • Inverter efficiency: Quality string inverters operate at 95–97% efficiency.
  • Dust and soiling: Accumulated dust can reduce output by 2–7% in dry months.
  • Shading: Even partial shading causes disproportionate output loss in string inverter systems.
  • Mismatch losses: Minor variations between panels in a string reduce the whole string's output.

What Is a Good Performance Ratio in Kerala?

PR RangeAssessment
Below 70%Poor — likely installation or shading issues
70–75%Average
75–80%Good
Above 80%Excellent — quality installation, minimal losses
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Rayenna targets 78–82% PR

We design all systems to target a PR of 78–82% through optimal cable sizing, shading analysis, quality inverter selection, and precise panel orientation. This is what separates a well-engineered installation from a basic one.

Why This Matters When Getting Quotes

When comparing quotes from different installers, ask about the expected PR for your installation. An installer who cannot answer this question, or who promises unrealistically high generation figures, is either not designing properly or not being honest. A realistic, well-calculated PR projection is the mark of a professional installation.

Ask Us About Our System Design Approach

We provide full generation projections with realistic PR calculations — before you sign, not after.

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