Principal Solar Institute

A community for development and installation professionals in the solar industry

The Principal Solar Institute Module Ratings

The Principal Solar Institute’s scientifically designed and certified combination of tests and performance standards provide an unbiased, comprehensive rating system – the PSI PV module rating. Seven essential characteristics related to initial and long-term PV module performance are combined to create the PSI Rating:

  • Actual Tested Maximum Power vs. Advertised
  • Temperature Coefficient at Maximum Power
  • Power at Low Irradiance to Power at High Irradiance Ratio
  • Normal Operating Cell Temperature (NOCT)
  • Total Area Efficiency
  • Negative Power Tolerance
  • Annual Power Reduction

These ratings allow you to make comparisons when analyzing PV modules and help you select the optimal PV module.

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PSI Ratings – PV Solar Modules from SweModule

Here are the PSI Ratings for modules from SweModule, calculated based on initial performance test data. If you don’t see a solar module that you are considering, contact us and we will try to add it.

Rank Manufacturer Model Type Power
(W DC)
PSI Rating Percentile
1SweModule265 xPolycrystalline2658.14*81
2SweModule260 xPolycrystalline2607.97*74
3SweModule255 xPolycrystalline2557.89*70
4SweModule250 xPolycrystalline2507.72*61
5SweModule245 xPolycrystalline2457.67*58
6SweModule240 xPolycrystalline2407.52*49
7SweModule235 xPolycrystalline2357.36*39
8SweModule230 xPolycrystalline2307.10*26
9SweModule225 xPolycrystalline2256.94*19
10SweModule220 xPolycrystalline2206.84*16

* Modules denoted with an “*” use estimated values for one or more characteristics. Manufacturers can contact us to provide the missing data for these PV modules.

NOTE: PSI Ratings are based on publicly available data, and are subject to change as additional data and proprietary analyses become available for long-term performance.