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 Isofoton

Here are the PSI Ratings for modules from Isofoton, 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	Isofoton	ISFP-270 White	Polycrystalline	270	8.52*	91
2	Isofoton	ISFP-270 Black	Polycrystalline	270	8.48*	91
3	Isofoton	ISFP-265 White	Polycrystalline	265	8.36*	88
4	Isofoton	ISFP-265 Black	Polycrystalline	265	8.32*	87
5	Isofoton	ISFT-255	Monocrystalline	255	8.30*	87
6	Isofoton	ISFP-260 White	Polycrystalline	260	8.20*	84
7	Isofoton	ISFP-260 Black	Polycrystalline	260	8.17*	82
8	Isofoton	ISF-255	Monocrystalline	255	8.13*	81
9	Isofoton	ISFT-250	Monocrystalline	250	8.12*	80
10	Isofoton	ISFP-255 White	Polycrystalline	255	8.06*	78
11	Isofoton	ISF-255 Black	Monocrystalline	255	8.05*	78
12	Isofoton	ISFP-255 Black	Polycrystalline	255	8.01*	76
13	Isofoton	ISFT-245	Monocrystalline	245	7.96*	73
14	Isofoton	ISF-250	Monocrystalline	250	7.95*	73
15	Isofoton	ISF-250 Black	Monocrystalline	250	7.88*	70
16	Isofoton	ISFP-250 White	Polycrystalline	250	7.88*	70
17	Isofoton	ISFP-250 Black	Polycrystalline	250	7.85*	68
18	Isofoton	ISF-245	Monocrystalline	245	7.82*	67
19	Isofoton	ISF-245 Black	Monocrystalline	245	7.73*	62
20	Isofoton	ISF-255 Clear	Monocrystalline	255	7.66*	57
21	Isofoton	ISF-240	Monocrystalline	240	7.66*	57
22	Isofoton	ISF-235	Monocrystalline	235	7.52*	49
23	Isofoton	ISFP-245 Black	Polycrystalline	245	7.50*	48
24	Isofoton	ISF-250 Clear	Monocrystalline	250	7.49*	47
25	Isofoton	ISFP-245 White	Polycrystalline	245	7.44*	44
26	Isofoton	ISFP-240 Black	Polycrystalline	240	7.35*	39
27	Isofoton	ISF-245 Clear	Monocrystalline	245	7.34*	38
28	Isofoton	ISFP-240 White	Polycrystalline	240	7.30*	36
29	Isofoton	IS-220/32	Monocrystalline	220	6.55*	8
30	Isofoton	IS-215/32	Monocrystalline	215	6.39*	6
31	Isofoton	IS-210/32	Monocrystalline	210	6.25*	5

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* 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.