Solar advice: Prefer strong brands and read the data sheets
Prefer panels of high performance and wattage (at the same dimensions), because that will allow you to yield more solar electricity from your roof and save on installation costs. If you live in an area with high rates of snowfall, it is recommended to consider the more stable double-glass panels.
Learn the panel specifications
But always take the time to read the small print – especially the panel specifications. You can find it in the data sheets of the panels. A key point is the temperature coefficient, which specifies by how much the output increases or decreases with every degree of difference from the standard temperature (25 degrees Celsius). With every degree of temperature increase, the output goes down by that factor, and vice versa.
Be positive tolerant!
Take note of the specified output tolerance: It denotes the width of the scattering of the panel’s nominal output on delivery. Always choose panels with a positive tolerance, i.e. output should only deviate upwards. Most manufacturers grant a voluntary performance warranty, which should ideally look like this: At least 90 percent performance within the first ten years and 80 percent after another ten years. The law in most European countries only specifies a warranty (liability for being free of defects) of two years. (HCN/HS)
Look at this, too:
Solar advice: The price alone is not everything
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