How much do solar panels cost to install?

A typical 8 kW residential solar system costs $20,000–$32,000 installed in 2026 (gross). Note: the 30% federal 25D credit expired for systems placed in service after Dec 31, 2025 — that $14,000–$22,400 'after credit' figure no longer applies. Per-watt installed pricing ranges $2.50–$4.00 depending on state, panel brand, and roof complexity. Adding battery storage (Tesla Powerwall, Enphase IQ Battery) adds $10,000–$18,000 per battery. Payback period in 2026 averages 10–14 years in sunny states with high electric rates (CA, AZ, NV, MA, NJ), 15–20+ years in low-rate states.