The same study also found that rain is not a satisfying way of cleaning solar panels. Solar panels that were cleaned professionally had a 12% higher output of electricity compared to those cleaned by rain.

How much money would it cost me to neglect solar panel cleaning? It is reasonable to assume that solar panels can loose 15-25% of their efficiency if not cleaned properly. This literally means that they will generate 15-25% less electricity, which you now will have to source from the utility company at their price rates. This easily adds a couple of years extra on the payback time.

How often should I clean my solar panels? In most places, there`s more pollution in the winter, which is why the spring is a good time to do an annual cleaning. Solar panels that are cleaned once and twice a year produce 3.5% and 5.1% more electricity respectively than those that are left uncleaned. However, some places do require extra attention.