Enter your state and monthly electricity bill to instantly calculate your estimated system cost, payback period, and 25-year savings — personalized to your location.
Avg rate: $31.0¢/kWh · 5.7 peak sun hrs/day
≈ 484 kWh/month
~25% of U.S. tracts qualify. Check eligibility ↗
We divide your annual kWh usage by your state's average peak sun hours × 365 days × 0.80 efficiency factor (accounting for real-world losses). Roof shading applies an additional adjustment factor.
Using 2026 average installed cost per watt by system size: ~$3.50/W for systems under 4 kW, ~$3.25/W for 4–7 kW, ~$3.00/W for 7–12 kW, and ~$2.75/W for larger systems. Get quotes from 3+ installers for your actual price.
Projects annual savings forward at 4% annual electricity rate escalation — the historical U.S. average since 2000. Subtracts $150/year maintenance and a $2,000 inverter replacement at year 12. Net savings = cumulative electricity savings − net system cost − maintenance.
Fourteen states with major above-ITC programs (SMART, SREC II, RSIP, state income tax credits, etc.) are factored in as simplified NPV estimates. Most states also have property tax exemptions and sales tax exemptions not fully reflected here — see your state guide for the complete picture.