| System Size | Before Credit | After 30% Credit | Best For |
|---|---|---|---|
| 4 kW | $10,000–$14,000 | $7,000–$9,800 | Small home, $75–$100/mo bill |
| 6 kW | $15,000–$21,000 | $10,500–$14,700 | Average home, $100–$150/mo bill |
| 8 kW | $20,000–$28,000 | $14,000–$19,600 | Larger home, $150–$200/mo bill |
| 10 kW | $25,000–$35,000 | $17,500–$24,500 | Large home, $200–$300/mo bill |
| 12+ kW | $30,000–$42,000 | $21,000–$29,400 | Large home + EV charging, $300+/mo |
Cash purchase gives the highest lifetime savings: you keep the 30% tax credit, pay no interest or lease fees, and own the system which adds $10,000–$20,000 to your home value. A solar loan (5–7% APR, 10–20 year term) requires no upfront cost but you pay interest over the loan term; net savings are still positive if your electricity rate is above $0.12/kWh. A lease or PPA (Power Purchase Agreement) requires $0 upfront and the installer owns the system; you pay a fixed rate for the electricity it produces (typically 10–30% less than utility rates). Leasing provides the smallest savings and does not increase your home value. About 60% of residential solar is purchased (cash or loan), 40% is leased/PPA.
Solar panels are warrantied for 25 years and typically produce electricity for 30–35 years. Output degrades about 0.5% per year, so after 25 years they are still producing about 87% of their original output. Inverters (which convert DC to AC power) last 12–15 years and cost $1,000–$2,000 to replace — budget for one inverter replacement over the system’s life. Microinverters (one per panel) last longer (25 years) but cost more upfront. Maintenance is minimal: an occasional spray with a hose if they get dusty, and monitoring the app for any performance issues.