How often should I clean my solar panels?

It depends.  As I mentioned in the previous article, where do you live?  Our company is located in the California.  It is not unusual for us to have wind gusts up to 50 MPH which blows the desert sand (actually pulverized granite) over the panels.  Heliotex is located in Palm Desert, CA in the desert area of the Coachella Valley.  In a test of my system on my home, I lost 11 ½ % in three months.  This of course can vary during the different seasons and with unusual weather conditions.

The National Renewable Energy Laboratories (NREL) has suggested that one can lose up to 25%.  However, again this is an average. 

              We have encountered locations with loses well in excess of 25%.  In one major California utility test area, we were told that at that specific location they were losing 38% of their output with half of that occurring in the first 30 days.  It should be noted that the panels were mounted at only a few degrees angle which makes dust capture worse.

                The most diligent of owners who clean normally do it approximately every three months.  Doing this ensures that your panels are clean for 100 days over a 25-year life cycle of which there is 9,125 days (excluding leap years).  In actual practice, most owners only wash their panels about once or twice a year.   While rain may assist in removing some of the debris, it does not clean.  It also provides a way for pollutants in the air to stick to the panels.  The mounting angle of the panels may also contribute to dirt and dust buildup.  Flat or nearly flat mounted panels retain more of their dirt and debris.

                The bottom line is that all experts agree that failure to clean a panel will result in power loss.