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.

Subscribe to our email list

Before using the PSI Ratings, you should subscribe to our email list to receive important updates from the Principal Solar Institute.

PSI Ratings – PV Solar Modules from Helios USA

Here are the PSI Ratings for modules from Helios USA, 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
1Helios USA9T6 420Monocrystalline4208.23*84
2Helios USA9T6 415Monocrystalline4158.13*81
3Helios USA9T6 410Monocrystalline4108.03*77
4Helios USA7T2 315Monocrystalline3158.01*76
5Helios USA6T 265Monocrystalline2657.97*74
6Helios USA9T6 405Monocrystalline4057.94*72
7Helios USA6T 260Monocrystalline2607.93*72
8Helios USA7T2 310Monocrystalline3107.89*70
9Helios USA9T6 400Monocrystalline4007.84*68
10Helios USA7T2 300Monocrystalline3007.79*65
11Helios USA7T2 305Monocrystalline3057.77*64
12Helios USA6TAMonocrystalline2557.77*64
13Helios USA6T 255Monocrystalline2557.77*64
14Helios USA9T6 395Monocrystalline3957.74*62
15Helios USA7T2 295Monocrystalline2957.67*58
16Helios USA9T6 390Monocrystalline3907.64*56
17Helios USA6T 250Monocrystalline2507.59*54
18Helios USA7T2 290Monocrystalline2907.54*50
19Helios USA6T 245Monocrystalline2457.52*49
20Helios USA7T2 285Monocrystalline2857.42*42
21Helios USA6T 240Monocrystalline2407.35*38
22Helios USA7T2 280Monocrystalline2807.28*35
23Helios USA6T 235Monocrystalline2357.19*30
24Helios USA6T 230Monocrystalline2307.04*23
25Helios USA6T p230Polycrystalline2307.03*23
26Helios USA6T p225Polycrystalline2256.90*17
27Helios USA6T p220Polycrystalline2206.78*14
28Helios USA6T p215Polycrystalline2156.64*10

* 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.