Compare normalized PV production, evaluate period cleaning value, follow equipment-specific service requirements and retain measured post-service evidence.
Collect module, inverter, monitoring and warranty documents, commissioning data and service history. Review accessible monitoring for faults, missing data or downtime. Record visible observations from a safe location and use the manufacturer’s service process for roof access, electrical faults or damaged equipment.
Align measured AC output, weather, availability and timestamps. Integrate output over the same window and distinguish instantaneous power from energy. Normalize the earlier and later performance basis before calculating annualized change, recording any method or equipment change that affects comparability.
Use supported site measurements or a model to estimate soiling loss and the share a cleaning would recover before the next rain, soiling cycle or service. Select the clean-potential or measured-soiled baseline correctly, value recovered self-use/export energy and compare the actual total service cost.
Use the module and inverter instructions for cleaning, inspection and service. Confirm suitable access, isolation, cleaning materials and permitted methods with the service provider. Record repairs, replacements and settings changes so later production comparisons can explain the new system condition.
Check alarms and monitoring continuity after service and compare production under a matched weather and availability basis. Record whether the expected soiling recovery occurred, whether a fault remains and whether the service affected system configuration. Keep raw measurements with the normalized result.
Export observations, service invoices, measured comparisons and the actual performance-normalization method. Add recurring service and replacement costs to the solar cash ledger. Revisit the maintenance plan when equipment instructions, site conditions, measured performance or tariff value changes.
Keep equipment identifiers, dated observations, alarms and service contacts together. · Retain the service scope, equipment instructions, date and any replaced components.
Integrate actual AC power intervals over the selected comparison window. · Integrate comparable post-service AC intervals.
Compare normalized measurements and report decline or growth without inferring its cause. · Calculate normalized before/after change on the documented basis.
Calculate recovered period energy and realizable net cleaning value. · Update the period-value case using observed recovery. · Save dated service-value cases for equivalent benefit periods.
Check the actual self-use and export compensation assumptions.
Include actual annual service and replacement cash costs.
Loading your checklist…
Temperature and operating conditions affect output; measurement comparisons need a consistent basis.
Retain model inputs and actual maintenance/replacement costs when comparing performance and cash flows.
A loss percentage relative to clean potential cannot be multiplied directly by measured soiled production to reconstruct the lost energy.
A future reviewer should be able to distinguish an observed meter value from a modeled weather correction.