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.