Do Solar Panels Need Cleaning in San Diego?
Yes, and the production loss from skipping it is bigger than most San Diego homeowners realize. Here's the data and what to do about it.
Short answer: yes, and in San Diego more than almost anywhere in California, because we have low rainfall, year-round sun, coastal salt, and high bird activity. Here's what actually happens to a San Diego solar system that never gets cleaned.
San Diego's climate is uniquely hard on solar panels
We get under 12 inches of rain in an average year, most of it concentrated in a few weeks. That means 9+ months of dust, pollen, salt, and droppings baking onto hot glass with no natural rinse. Inland and coastal homes are both affected; the type of dirt just changes.
How much production is your dirty array actually losing?
Dirt and debris can block sunlight, but the effect varies with the amount of buildup, panel tilt, rainfall, shading, and equipment condition. We don't have a verified typical loss figure for San Diego homes. Compare monitoring data under similar weather conditions before and after cleaning rather than expecting a fixed percentage gain.
What about rain? Doesn't that clean them?
Rain rinses light dust but bakes on bird droppings, salt, and pollen, the things actually costing you production. A San Diego rainstorm typically makes panels look cleaner without restoring meaningful production.