Just as a grimey window does not transmit as much light as one that’s sparkling clean, dirty solar panels will not produce as much energy as panels that are clean. But cleaning solar panels isn’t as easy as washing windows. Nor is it easy to figure out when they need to be cleaned.

Both homeowners and commercial solar installations have to deal with issues related to keeping solar panels clean. For homeowners, the best advice in rainy areas is to have the panels professionally washed every three to five years; more often for larger systems, and in areas that are very dry and dusty. Commercial customers consider the cost-benefit tradeoffs more carefully. It may cost $5,000 per year to clean a large system, but that 5% increase in energy output may be worth $10,000 -- hence regular cleaning pencils out.

With over 25 Gigawatts of installed solar capacity in the U.S., there is a need for professional solar panel cleaning services. But not a lot of Windex; for safety and environmental reasons, panels are usually cleaned with deionized water. And NEVER just hose off your panels; minerals in the water will create a white film on the glass. If you can work safety on a ladder and on your roof, you can wash the panels yourself with a gentle soap solution.

Please Listen Up to this week’s Energy Show on Renewable Energy World as we welcome Jay Welsh, CEO of Solar Maids, the leading professional panel cleaning service. Jay shares his tips on cleaning residential systems, as well as the wider range of operations and maintenance services that Solar Maids provides.