How Much Does Dirt Actually Reduce Solar Output?
What UCSD and NREL research can tell you about soiling, and why your system needs its own measurements.
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.
Industry research on soiling rates
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.
How to compare your own monitoring data
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.
Why the loss grows over time
Soiling and output vary from system to system. Check visible buildup, panel cleaning instructions, and monitoring data under similar weather conditions. Cleaning isn't guaranteed to cover its cost, and a thermal image isn't an electrical diagnosis.