Solar panels perform at their best when they are clean and free of dirt. In practice, solar panels are exposed to dust, sand, pollen, air pollution, and bird droppings. This dirt forms a layer on the surface of the panels, preventing sunlight from reaching the solar cells effectively. The result is a lower energy yield and a less efficient system.
Practical measurements show that dirty solar panels can generate 5 to 20% less electricity. This means that an installation unnecessarily loses energy even though the sun is shining just as brightly.
How dirt affects the performance of solar panels
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Dust and sand reduce light transmittance
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Pollen and fine dust accumulate, especially during dry periods
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Bird droppings can cause significant local yield losses
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Uneven soiling can reduce the efficiency of entire panels
For an average solar panel installation, this can lead to 100 to 300 kWh less yield per year.
Keeping solar panels clean: structural maintenance pays off
Whether solar panels are cleaned by the owner themselves or by a professional: regular maintenance is essential for the panels to absorb sunlight optimally. Clean solar panels ensure:
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A higher and more stable yield
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Less long-term soiling
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Better protection of the panel surface
Professional and efficient cleaning products, such as telescopic poles with soft brushes, make it possible to clean solar panels safely and thoroughly without damaging the panels or the roof.
What do clean solar panels yield?
When solar panels are kept clean, the yield can be 10–20% higher than with dirty panels.
For an installation of 4,000 kWh per year, this can eventually provide hundreds of kWh of extra electricity — without additional panels or investments.
How often should solar panels be cleaned?
For optimal performance, it is recommended to clean solar panels 1 to 2 times a year:
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Spring: removal of pollen, dust, and sand
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Autumn: after summer soiling and dry periods
In areas with a lot of industry, agriculture, or birds, more frequent cleaning may be useful.
