It’s Crucial to Wash Your Solar PV Panels


Over time, dirt can significantly decrease amount of the sun’s energy that solar panels can capture. Meaningful improvements in the PV performance at four sites were recently noticed after module washing, with increased measured efficiency varying from 9% to 26%. This translates to significant savings from washing panels. 

Owners of solar installations want to capture as much of the sun’s energy as they can. Dust and dirt on PV panels, a common issue especially in desert conditions and locations close to open land, decrease the amount of sunlight that panels can capture. The economic impact of dirty PV modules can be particularly serious during the summer.

According to an article on Renewable Energy World, meaningful improvements in the PV performance at four sites were measured after the modules were washed. Increases in efficiency, which ranged from 9% to 26%, showed that system owners can realize significant savings by washing their panels.

Homeowners and businesses who acquired their PV system through a power purchase agreement (PPA) should take a close look at their PPA to see if it includes clauses for PV system cleaning or any performance guarantees.

According to Renewable Energy World, “the frequency of the wash should depend on the location and weather conditions…. In general, washing the modules two to three times a year should be sufficient to make it worthwhile. Beyond this, in locations where the price of water is high, the cost of cleaning may not sufficiently offset the intended benefit of the wash.”