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 Westinghouse Solar

Here are the PSI Ratings for modules from Westinghouse Solar, 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	Westinghouse Solar	WTW-250-1-DC4-0-B	Polycrystalline	250	9.71*	99
2	Westinghouse Solar	WTW-250-1-AC2-D-B	Polycrystalline	250	9.71*	99
3	Westinghouse Solar	WTW-245-1-DC4-0-B	Polycrystalline	245	9.50*	98
4	Westinghouse Solar	WTW-245-1-AC2-D-B	Polycrystalline	245	9.50*	98
5	Westinghouse Solar	WTW-240-1-AC2-D-B	Polycrystalline	240	9.29*	98
6	Westinghouse Solar	WTW-240-1-DC4-0-B	Polycrystalline	240	9.29*	98
7	Westinghouse Solar	WS-195-1AC1-A-B	Monocrystalline	195	7.85*	68
8	Westinghouse Solar	WS-195-1AC3-B-B	Monocrystalline	195	7.85*	68
9	Westinghouse Solar	WS_195_1_DC0_0_B	Monocrystalline	195	7.85*	68
10	Westinghouse Solar	WS_290_1_DC0_0_B	Polycrystalline	290	7.68*	59
11	Westinghouse Solar	WS-190-1AC1-A-B	Monocrystalline	190	7.65*	57
12	Westinghouse Solar	WS_190_1_DC0_0_B	Monocrystalline	190	7.65*	57
13	Westinghouse Solar	WS-190-1AC3-B-B	Monocrystalline	190	7.65*	57
14	Westinghouse Solar	WLW-240-1-AC0-D-B	Polycrystalline	240	7.49*	47
15	Westinghouse Solar	WLW-240-1-DC0-0-B	Polycrystalline	240	7.49*	47
16	Westinghouse Solar	WLW-240-1-DC0-0-BL	Polycrystalline	240	7.49*	47
17	Westinghouse Solar	WLW-240-1-AC1-A-B	Polycrystalline	240	7.49*	47
18	Westinghouse Solar	WLW-240-1-AC2-D-B	Polycrystalline	240	7.49*	47
19	Westinghouse Solar	WLW-240-1-AC3-B-B	Polycrystalline	240	7.49*	47
20	Westinghouse Solar	WLW-240-1-DC1-0-B	Polycrystalline	240	7.49*	47
21	Westinghouse Solar	WS-185-1AC3-B-A	Monocrystalline	185	7.45*	45
22	Westinghouse Solar	WS-185-1AC3-B-B	Monocrystalline	185	7.45*	45
23	Westinghouse Solar	WS_185_1_DC0_0_B	Monocrystalline	185	7.45*	45
24	Westinghouse Solar	ST-185-1	Monocrystalline	185	7.45*	45
25	Westinghouse Solar	WS-185-1AC1-A-A	Monocrystalline	185	7.45*	45
26	Westinghouse Solar	WS-185-1AC1-A-B	Monocrystalline	185	7.45*	45
27	Westinghouse Solar	WS_185_1_DC0_0_A	Monocrystalline	185	7.45*	45
28	Westinghouse Solar	WS_280_1_DC0_0_B	Polycrystalline	280	7.41*	42
29	Westinghouse Solar	WLW-235-1-AC0-D-B	Polycrystalline	235	7.39*	41
30	Westinghouse Solar	WLW-235-1-AC2-D-B	Polycrystalline	235	7.39*	41
31	Westinghouse Solar	WLW-235-1-AC1-A-B	Polycrystalline	235	7.39*	41
32	Westinghouse Solar	WLW-235-1-DC0-0-B	Polycrystalline	235	7.39*	41
33	Westinghouse Solar	WLW-235-1-DC0-0-BL	Polycrystalline	235	7.39*	41
34	Westinghouse Solar	WLW-235-1-DC1-0-B	Polycrystalline	235	7.39*	41
35	Westinghouse Solar	WLW-235-1-AC3-B-B	Polycrystalline	235	7.39*	41
36	Westinghouse Solar	WS-180-1-DC0-0-A	Monocrystalline	180	7.22*	31
37	Westinghouse Solar	ST-180-1	Monocrystalline	180	7.22*	31
38	Westinghouse Solar	WS_180_1_DC0_0_B	Monocrystalline	180	7.22*	31
39	Westinghouse Solar	WS_270_1_DC0_0_B	Polycrystalline	270	7.21*	31
40	Westinghouse Solar	WLW-230-1-DC1-0-B	Polycrystalline	230	7.17*	29
41	Westinghouse Solar	WLW-230-1-AC0-D-B	Polycrystalline	230	7.17*	29
42	Westinghouse Solar	WLW-230-1-DC0-0-BL	Polycrystalline	230	7.17*	29
43	Westinghouse Solar	WLW-230-1-DC0-0-B	Polycrystalline	230	7.17*	29
44	Westinghouse Solar	WLW-230-1-AC1-A-B	Polycrystalline	230	7.17*	29
45	Westinghouse Solar	WLW-230-1-AC2-D-B	Polycrystalline	230	7.17*	29
46	Westinghouse Solar	WLW-230-1-AC3-B-B	Polycrystalline	230	7.17*	29
47	Westinghouse Solar	ST-175-1	Monocrystalline	175	6.99*	21
48	Westinghouse Solar	WS-175-1AC3-B-A	Monocrystalline	175	6.99*	21
49	Westinghouse Solar	WS_175_1_DC0_0_B	Monocrystalline	175	6.99*	21
50	Westinghouse Solar	WS-175-1AC1-A-A	Monocrystalline	175	6.99*	21
51	Westinghouse Solar	WS-175-1-DC0-0-A	Monocrystalline	175	6.99*	21
52	Westinghouse Solar	WS_260_1_DC0_0_B	Polycrystalline	260	6.94*	19
53	Westinghouse Solar	ST-170-1	Monocrystalline	170	6.82*	15
54	Westinghouse Solar	WS-170-1-DC0-0-A	Monocrystalline	170	6.82*	15
55	Westinghouse Solar	WS_170_1_DC0_0_B	Monocrystalline	170	6.82*	15
56	Westinghouse Solar	WS-165-1-DC0-0-A	Monocrystalline	165	6.19*	4
57	Westinghouse Solar	ST-165-1	Monocrystalline	165	6.19*	4
58	Westinghouse Solar	WS_165_1_DC0_0_B	Monocrystalline	165	6.19*	4

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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.