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    Solar PV Sizing Calculator (kW)

    How is annual solar production estimated?

    It follows the NREL PVWatts approach: daily kWh equals system size in kW times peak sun hours times the performance derate factor, then multiplied by 365 for the year. The default 0.8 derate accounts for inverter, wiring, soiling, and temperature losses. Peak sun hours vary by location and season, so use a local solar resource value rather than the 4.5 default for a real estimate.

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    Use the Solar PV Sizing Calculator (kW) to get an exact answer for your inputs.

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    Related questions

    Estimates and general guidance only. Verify against your local code and AHJ before any installation. Gas, electrical, and refrigerant work is hazardous to untrained users.

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