Only a dozen companies produce solar panels that are as good as the ones we saw in 2021.
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Run an expert eye over the solar panel spec sheet
Unlike other solar panels, solar panels are not all-purpose. They can also be very useful if you’re not sure which type of module to buy. A good solar panel specification sheet can help you make an informed choice.
Solar panel efficiency: REC, 20.9%
The efficiency of a solar panel is the amount of electricity it can produce after taking advantage of the sunlight that hits it. Generally, it varies between 15% and 20%.
One of the most notable solar panels that is good is the REC 365W Alpha, which has a 20.9% efficiency. It’s made by REC Alpha.
Lifelong performance: Q Cells, 93.1% of nominal power in year 10
Performance warranties are usually provided by top manufacturers for solar panels. They promise that their products will last for up to 25 years.
For Hanwha Q Cells, their longevity guarantee is 85% of the nominal power for up to 25 years.
In reality, Q CELLS modules can endure a degradation rate of 0.3%. However, they can still produce a consistent rate of not greater than 0.54%.
Performance in partial shade conditions: Panasonic, less than 25% output loss
Although manufacturers can’t predict how long a solar panel will be shaded due to its design, they can provide helpful details such as the mechanical specifications of their products.
The Panasonic HIT 330W is considered the best in this category due to its 4 bypass diodes. If a solar cell is completely shaded, these components prevent the cell from affecting the others.
Wind resistance: Canadian Solar, 180 mph wind
During hurricane season, high winds can cause solar panels to lift up or fall down. As a result, many of the world’s best solar modules are certified to withstand wind speeds of up to 240 mph.
Canadian Solar, on the other hand, claims that its panels can endure wind loads of up to 4000 Pa. Although they weren’t able to withstand Hurricane Patricia, they’re still more reliable than competing products.
Warranty: Silfab, 30-year warranty
Performance and equipment warranties are typically provided by solar panel manufacturers. These warranties help protect the panels from various types of wear and tear.
Silfab offers the longest solar panel warranty on the market: 25-year workmanship and 30-year performance warranty.
Although the label doesn’t reflect the quality of the solar panels, it’s still a good sign that the manufacturer has a good reputation in the industry.