Solar ROI Calculator Guide: Inputs That Actually Matter
Inputs that matter
Start with 12 months of SCE bills (kWh and $), roof orientation, shading, and planned loads (EV, pool, AC). Generic national averages underestimate Orange County savings.
Payback vs IRR
Simple payback divides net cost by year-one savings. IRR accounts for rate escalation over 25 years—often 12–18% in high-rate territories.
NEM 3 export discount
Calculators assuming full retail export overstate returns. Insist on hourly or seasonally adjusted export modeling.
Sensitivity analysis
Model +20% usage (teen drivers, EV) and +4% annual rate hikes. See 710W pricing for equipment tier comparisons.
Try our calculator then confirm with an engineer-verified free solar quote.
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