Now that you’ve made the switch to renewable energy by adding solar panels to your home, you may wonder about the upkeep. The good news? Once installed, your solar panels require little care.

Researchers at the University of California, San Diego, set out to determine whether the cost of having solar panels cleaned would be offset by any improvements in performance.

The study was conducted during a summer drought in southern California in 2010. The area was without measurable rainfall for approximately 145 days. Even without any rain washing away dirt, panels that were not physically cleaned lost a mere 7.4 percent efficiency in total.

For a typical 5kWh residential solar system, panels washed halfway through the study period would have realized efficiency equating to a mere $20 gain in electricity production. Panels averaged a bit less than 0.05 percent efficiency loss per day.

Leave Cleaning Solar Panels to Mother Nature

Their findings show there is no need to hire someone to clean your solar panels. Mother nature–by way of rainfall–will do the job for you, at the perfect price. The average annual rainfall in the Mid-Atlantic is over 42.75 inches, more than enough rain to wash away any accumulated dirt and dust — keeping your panels operating optimally.

Your system does carry a warranty that should give you peace of mind for years to come regarding maintenance-related performance, so you should not have to pay extra for yearly maintenance, either, other than under a few special circumstances.

The only reason your solar panels may need attention is if a large tree branch or other object, is found to be blocking the sun from fully reaching your panel, due to a recent storm or other event. This may significantly reduce your panel’s efficiency, depending on amount blocked. In this case, you would probably want to have the debris removed rather than waiting for it to fall away on its own.

One other unique circumstance under which you may want to consider having your panels cleaned is if there is an unusual amount of dust in the air, such as being in close proximity to a construction site, particularly if your area is also experiencing a season short on rainfall.

Another special circumstance would be if your home has an unusually large installation. Then, you may want to push the pencil a bit more to see of the economy of scale makes it worth hiring someone rather than letting the rain do its job.

Under normal conditions, however, your solar panels should last well over 40 years and your solar inverters for more than 10, without requiring special care.