Panel cleaning periodicity can vary from region to region. Some areas require only a yearly cleaning. some areas which have a lot of construction, dust and pollution could require cleaning that are more frequent. In Central Texas we have seen semi-annual cleaning beneficial to your solar system.
Consider the windshield on your car. Over time it gets dirty and it eventually needs to be cleaned. What do you do? You either turn on your wipers or you run your car through a car wash.
a car wash cleans your windshield, a contact clean will clean your solar panels.
Maintenance can come in the form of just a visual inspection, cleaning or the replacement of parts. Solar panels are sealed silicon arrays, they are typically surrounded by a metal frame and covered by a tempered glass. Over time these seals might begin to harden and leak. Cleaniyour panels can help reduce this affect.
* dirty and dust carried through the air, especially in areas where construction is present.
* bird and insect droppings.
* airborne chemicals (pollution)