We recommend an annual cleaning for your solar PV system to maximize the performance. You can loose up to 25% of your production by dirty panels or compromised wiring. The graph below represents a graph showing the increased production after we cleaned and serviced it in August of 2011. As you can see the Blue line represents 2011 and the Green line represents 2012. The system showed over a 30% increase in the prime months and now the customer will be receive a check from PG&E at the end of their true-up period instead of owing.