By Dan Piepho, CEO, Every Detail Solar · 2026 First Edition · Annual refresh
The Every Detail Solar Soiling & Recovery Report measures how much production commercial solar arrays lose to soiling and how much a professional wash recovers, using real pre- and post-wash data from the sites we service. This 2026 first edition is deliberately built as a methodology-and-early-findings release: we publish how we measure, what the independent research says, and the findings we can stand behind today - and we grow the dataset every quarter rather than inflating it.
Why this report exists
Almost nobody in commercial solar cleaning publishes measured recovery data. The industry runs on headline percentages with no attribution. We perform the washes, so we can measure the difference - and we would rather publish a smaller, honest dataset that trade press and O&M teams can actually cite than a big invented one. That is the whole point of this document.
The independent baseline (what NREL and peer-reviewed research show)
Before our own numbers, here is the sourced context every figure on this site is anchored to:
| Finding | Source |
|---|---|
| ~3-5% average annual energy loss to soiling (insolation-weighted soiling ratio), mapped across hundreds of U.S. sites | U.S. National Renewable Energy Laboratory (NREL) PV soiling research |
| Soiling power loss exceeding ~1% per day during heavy dust accumulation | Peer-reviewed PV field studies (Solar Energy / ScienceDirect) |
| A single dust storm can cut output ~20% short-term | Peer-reviewed PV field studies |
| Rainfall did not fully restore performance after pollen soiling | NREL pollen-soiling research |
The takeaway: average loss is a few percent, but the tail is long, and in dry or dusty regions the real number is well above the national average. That is why site-specific measurement matters more than any single headline figure.
How we measure (the methodology)
- Baseline. Capture pre-wash production from inverter or string-level monitoring where available; otherwise a reference-cell or short-window output comparison under known irradiance.
- Wash. Deionized-water clean at our published throughput (~150 panels/hr rooftop and ground-mount, ~225 panels/hr carport/canopy).
- Post-wash. Recapture production under comparable irradiance and temperature.
- Normalize. Adjust for irradiance and module temperature so the delta reflects soiling recovery, not weather.
- Report. Publish the recovery with mount type, region, and season attached - and the method so it can be checked.
Early findings (2026 first edition)
Our early measurements are consistent with the independent baseline above: recovery is smallest on low-soiling, well-rinsed rooftops and largest on dry-region ground-mount and desert sites that have gone a full soiling season without a wash. We are intentionally not publishing a portfolio-wide "average recovery %" yet, because our verified sample is still small and a small-sample average would mislead more than it informs.
Building the dataset: we are actively expanding measured, consented site data across California, Arizona, Texas, and Nevada. If you operate a commercial or utility array and want your site included (with your production data kept confidential and only reported in anonymized, aggregated form), contribute your site. Verified sites in each state anchor that state's numbers - and the first verified operator in a state becomes the reference case for it.
How the numbers connect to your decision
Use the report the way an O&M manager should: find the closest match to your mount type and region, treat it as a starting estimate, then get a site-specific measurement. That is exactly what our pricing methodology and free production-loss estimate are built to produce.