How Often Should I Clean Solar Panels?
Soiling. Dirt, dust, bird excrement, and snow can filter out some sunlight from the PV cells.
According to the National Renewable Energy Laboratory, modules in areas that experience high levels of particulate pollution and infrequent rain can experience soiling losses of up to 25%, especially on flat-mounted arrays.
Isolated soiling that remains for an extended time can cause “hot spots” that prematurely degrade or damage PV cells. It’s nothing a squeegee, some water, and a little elbow grease can’t conquer keep your modules clean.
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In many areas, a periodic rainfall can do the job. But if it’s been a long time since the last rain and you notice a fine layer of dirt or dust building up, you will boost your system’s energy production with a little cleaning.
Clean Solar Panels | How Often Should I Clean My Solar Panels? Maximizing Performance

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