Solar panel washing tool - GIF

[mklotz]

I still can't figure out how much dirt affects solar panel efficiency.

This experiment...

https://www.hesolarllc.com/cleaning-dirty-solar-panels/

seems to indicate a two to three percent improvement in output after cleaning.

This somewhat less scientific article...

https://www.popularmechanics.com/sci...f-solar-power/

suggests much larger losses.

My guess is that if you live at a higher latitude where it rains frequently, it's nothing to worry about. Much better to concern yourself with the very poor efficiency of the cells themselves.