What sort of cleaning regime should I have for a solar energy system, and do PV and solar-thermal panels need to be treated differently?

  • Location, location, location. Many factors are involved: traffic intensity, average rain and wind, angle of the panels, height above the ground, nearby industry,.... Do you have a specific location in mind?
    – user2451
    Jun 17, 2016 at 14:27

2 Answers 2


I only have one anecdote and avague idea: An agrarian schooling center (Haus Düsse) in Germany clean their PV System once a year, and clean/dirty means a difference of 10% effectiveness. However, as this is basically a small farm with lifestock, different grain treatments, lots of diesel vehicles etc. you would expect far more dust there than at a lot of other places. 3 years ago, they were starting to systematically analyze what's the most economic cleaning regime.

  • The anecdotal evidence I've heard here in Montana, USA seems to confirm this. Jun 12, 2013 at 21:52
  • To add another anecdote: I just visited a roof mounted PV system (>50 kW) with a very small roof pitch/slope of say 10°. The operator claimed to clean the modules each year in the springtime as the agricultural workings on the farm foul them significantly. Story 2: I am the "caretaker" of another PV system (18 kW) roof mounted, about 30° slope and we do not clean them on a regular basis as we do not see a significant drop in output power (so far), operational time 'bout five years now.
    – Ghanima
    Mar 5, 2015 at 0:23

I work and attend classes at a University in Florida. Our 100kW system has been installed for more than five years without a single cleaning. I have walked the solar field several times and can confirm that no significant dust has collected. (The angle of inclination is about 27 degrees.) But, Florida rains a lot and that helps keep everything clean. I imagine desert areas with wind storms would be much worse. But a duster at best or some cotton rags and dish-soap at worst would be more than enough to keep any system clean.

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