Performance, O&M & Monitoring
What is a realistic performance ratio?
Reviewed by SolvSolar · Last reviewed:
A realistic performance ratio for a well-designed rooftop system is 0.75–0.82 after temperature, soiling, mismatch, cable and inverter losses. Treat anything above 0.85 in a proposal as optimistic marketing rather than an engineering estimate. Ratios below 0.70 usually point to heavy shading, poor ventilation behind modules, or undersized cabling.