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
1	Helios USA	9T6 420	Monocrystalline	420	8.23*	84
2	Helios USA	9T6 415	Monocrystalline	415	8.13*	81
3	Helios USA	9T6 410	Monocrystalline	410	8.03*	77
4	Helios USA	7T2 315	Monocrystalline	315	8.01*	76
5	Helios USA	6T 265	Monocrystalline	265	7.97*	74
6	Helios USA	9T6 405	Monocrystalline	405	7.94*	72
7	Helios USA	6T 260	Monocrystalline	260	7.93*	72
8	Helios USA	7T2 310	Monocrystalline	310	7.89*	70
9	Helios USA	9T6 400	Monocrystalline	400	7.84*	68
10	Helios USA	7T2 300	Monocrystalline	300	7.79*	65
11	Helios USA	7T2 305	Monocrystalline	305	7.77*	64
12	Helios USA	6TA	Monocrystalline	255	7.77*	64
13	Helios USA	6T 255	Monocrystalline	255	7.77*	64
14	Helios USA	9T6 395	Monocrystalline	395	7.74*	62
15	Helios USA	7T2 295	Monocrystalline	295	7.67*	58
16	Helios USA	9T6 390	Monocrystalline	390	7.64*	56
17	Helios USA	6T 250	Monocrystalline	250	7.59*	54
18	Helios USA	7T2 290	Monocrystalline	290	7.54*	50
19	Helios USA	6T 245	Monocrystalline	245	7.52*	49
20	Helios USA	7T2 285	Monocrystalline	285	7.42*	42
21	Helios USA	6T 240	Monocrystalline	240	7.35*	38
22	Helios USA	7T2 280	Monocrystalline	280	7.28*	35
23	Helios USA	6T 235	Monocrystalline	235	7.19*	30
24	Helios USA	6T 230	Monocrystalline	230	7.04*	23
25	Helios USA	6T p230	Polycrystalline	230	7.03*	23
26	Helios USA	6T p225	Polycrystalline	225	6.90*	17
27	Helios USA	6T p220	Polycrystalline	220	6.78*	14
28	Helios USA	6T p215	Polycrystalline	215	6.64*	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.