A study conducted at the University of Turku, Finland, investigated how household cleaning products affect the ability of solar panel glass to transmit light. The results of the study were presented at the 41st European Photovoltaic Solar Energy Conference and Exhibition and in the conference procee...
Most cleaning agents, such as glass cleaner and isopropanol, proved suitable for cleaning the studied solar panel glass.
The exception was dishwashing detergent and the results suggest that it should not be used when cleaning solar panels. Even dirty glass transmitted more light than glass cleaned with dishwashing detergent.
The study found that the optical properties of the studied anti-reflective coating on solar panel glass did not deteriorate as a result of chemical cleaning—except when dishwashing detergent was used.
It is unlikely that dishwashing detergent damages the glass. However, rinsing does not seem to be sufficient, as the transmittance of the solar panel glass cleaned with detergent did not return to the pre-cleaning level after the rinsing.
"Even though the glass looks clean when cleaned with detergent, its ability to transmit light is significantly impaired. Therefore, a clean-looking end result does not guarantee optimal performance," says Research Assistant Julianna Varjopuro.
TL;DR - dish cleaner removes the anti-reflective coating but glass cleaner does not. And once lost, it does not come back.
glass cleaner is good at cleaning glass and dishwasher detergent isn't, i mean it's good to be certain but one could also have guessed that to be the case
Small chance of tap water, high pressure hose because I am not climbing on the roof, that's rather high and Im not interested in being high enough to leave an impact hole when I fall.