One of the most common questions we receive from both prospective and existing clients is whether or not solar panels require manual cleaning.
The answer to this question is - in most circumstances - no, you do not have to regularly clean your solar panels to avoid major performance loss. In Arizona, the rain received throughout the year is sufficient to remove natural residue build up on rooftop solar panels. Numerous studies have been conducted, including an investigation at the University of Arizona*, showing a minimal (2%) increase in annual energy production from frequent cleaning of panels.
If you do, however, decide to clean your solar panels, it is best to take proper precautions to avoid causing thermal stress to the modules. It is recommended that you rinse only with water, and avoid cleaning at times that will dramatically change the temperature of the modules. Always avoid putting cold water on hot solar panels. It is best to wash during the early morning before the panels begin absorbing heat from daylight. A light rinsing with water to clear away natural debris and dust buildup is generally all that is needed to return your panels to their maximum efficiency. If there are bird droppings or other deposits that do not readily wash off, you may use a soft sponge with a steady flow of water to remove them.
At TFS, we maintain pro-active data monitoring of all solar installations, allowing us to track system production and alert a customer to any issues or potential red flags in their generation levels. Data monitoring is also available on the client’s end as well, providing easy access to generation levels at home. While solar panels are very durable and require little to no cleaning upkeep, occurrences such as power outages can occasionally result in a need to manually re-establish connection between your home and your solar system, which our data monitoring allows us to keep aware of, frequently resulting in a prompt diagnosis, repair, and follow up before the client notices.
*University of Arizona study: http://uapv.physics.arizona.edu/publications.php
Rinse solar panels with water from a standard garden hose
Carefully move any debris such as sticks or leaves from the surface of panels
Gently wipe panel surface with a wet rag or soft sponge to remove persistent bird droppings
Wash panels in the early morning before the sun rises to avoid temperature fluctuation
Avoid washing panels in the daytime once they have begun absorbing heat
Do not scrub the surface of the panels with any rough or coarse materials
Do not use chemical cleaning solutions to wash panels - water is sufficient
Do not douse panels in water of any extreme temperature, hot or cold