In order to obtain the highest possible return from your solar modules, it is best to clean them on a regular basis. Depending on your location and the environmental factors, usually one cleaning per 1 to 5 years is sufficient. However, be on the alert when you are looking for a supplier for the cleaning of your installation.
“Some companies promise you an extra return of 7 to 8 percent after cleaning”, says iLumen’s CEO Ismaël Ben-Al-Lal in Het Belang Van Limburg. “If that return is not achieved, you do not have to pay the cleaning.”
Sounds nice, but unfortunately too good to be true. “After this cleaning, the efficiency actually increases by 7 to 8 percent, immediately readable on the inverter. This way you will be persuaded to also have the rest of the installation cleaned, “Ben-Al-Lal continues.
How, then, can this sudden return increase be explained? “The PV owner is for sure contacted by the cleaning company on a warm, sunny day, right at noon. The sudden extra return is not achieved, however, because the dirt has been removed, but because the solar modules are cooled by the water. It is especially the latter that provides the extra return. And that is, of course, only very temporary. ”
You better be warned…