TRANSPARENT BY DESIGN
How the calculator works
- Cleaning cost = panel count × $15.
- Clean-system kWh for the period = annual generation × months ÷ 12, unless you enter the seasonal override.
- Recovered kWh = clean-system period kWh × average recovered output ÷ 100.
- Value per recovered kWh = share used at home × avoided import rate + exported share × export credit.
- Net savings = recovered kWh × blended value − cleaning cost.
Choose inputs that match the question
The average recovered percentage is the difference between cleaning once and leaving the array uncleaned over this period, expressed as a share of clean-system production. It is not module conversion efficiency, lifetime degradation, or a one-day power increase. Allow for rain, remaining deposits, and new buildup. The tool does not infer this percentage from your panel count or photos.
Annual generation divided evenly across months is a simple approximation. Solar production is seasonal. Use the optional period-generation override with the months you are comparing when available. PVWatts can provide a separate production estimate; this calculator does not call PVWatts or claim its default values are a local forecast. If using PVWatts, separate soiling from other losses so it is not counted twice.
The defaults of 20 panels, 12,000 annual kWh, 2% recovery, 3 months, and the electricity rates are editable examples. A global soiling statistic is not the benefit from a single visit. Compare the result with IEA PVPS research and our cleaning value guide.
This estimates one visit within 1–12 months. It does not multiply savings across future years, add avoided repairs, or value appearance. It excludes battery conversion losses, tariff tiers, export caps, taxes, and unquoted extras. For those cases, enter an appropriate effective energy value or request a more detailed review.
Break-even recovered kWh = cleaning cost ÷ blended value. If the value is zero, there is no electricity-only break-even. The calculator shows an out-of-range message if the required recovery is above its 30% scenario limit; it never recommends that gain.