When solar panels get dirty, their efficiency decreases because the cells need sunlight to produce energy.
Dust, bird droppings, or other residues block light from reaching the cells, reducing power output.
Solar panels are tested under standard conditions of 1000 W/m² irradiation and 25 °C temperature, and they produce the rated power shown on their labels under these conditions.
If we allow dirt or any external factor to block sunlight, the panels will generate less energy.
Temperature is also an important factor to keep in mind.
The effect of dirt is not only power loss.
If dirt accumulates unevenly and remains for a long time, it can cause hot spots — localized overheating on the panel surface.
These hot spots can damage the solar cells, reducing their lifetime and efficiency.
In simple terms, it’s like a burn mark on the cell.
For this reason, you should especially watch out for bird droppings, which can cause permanent damage.
Always use soft, lime-free (deionized) water for cleaning.
Unknown or harsh chemicals can damage the anti-reflective coating on the glass or cause surface degradation.
Panel manufacturers typically provide 10-year mechanical and 25-year performance warranties, but damage caused by improper cleaning is not covered by warranty.
You can easily get lime-free water using water softeners or purification systems available on the market.
If your solar system is installed on a roof, having a small purification system will make maintenance much easier.
⚠️ SAFETY FIRST!
Do not step on the panel surfaces.
Be careful around cable trays.
Remember: DC cables may carry around 800 V DC voltage.
Roof surfaces may be slippery — use lifelines (horizontal safety lines) if needed.
Use a soft brush that will not scratch the glass surface.
For stubborn stains, use a mild glass cleaner, but always test it on a small area first.
If you notice lime stains at the bottom of the panels after cleaning, it means your method or water quality needs improvement.
In such cases, consider getting help from professional solar cleaning companies.
Cleaning frequency depends on the local environment and dust level.
Too frequent or too rare cleaning is not ideal — adjust your schedule based on how quickly panels get dirty.