In California, a 2.6-kW system for an average home costs about $6,653 after incentives in 2026, saves about $686 in the first year and pays back in 8.9 years.
| Item | Amount |
|---|---|
| Solar, 2.64 kW × $2.52/W | $6,653 |
| Federal credit (0%) | $0 |
| Net cost | $6,653 |
| Scenario | Net cost | Year-1 savings | Payback | 25-yr net |
|---|---|---|---|---|
| State averages (above) | $6,653 | $686 | 8.9 yr | $15,582 |
| Rates rise 5.6%/yr (2020–25 pace) | $6,653 | $686 | 8.3 yr | $23,534 |
| Rates stay flat | $6,653 | $686 | 9.9 yr | $9,504 |
| Survey price $3.3/W (LBNL) | $8,712 | $686 | 11.4 yr | $13,523 |
| Add 13.5-kWh battery | $21,219 | $1,356 | 13.4 yr | $25,004 |
| Size to 100% of use instead | $9,979 | $1,029 | 8.9 yr | $23,373 |
Verdict: at average California numbers, solar is a solid investment in 2026 — payback takes 8.9 years, leaving you $15,582 ahead after 25 years. The main reasons: electricity that costs more than in all but one state; strong sun (the 5th-best yield of 51); export credits below retail (net billing, exports earn 4.1¢/kWh), so only the solar you use yourself earns full value. Pay cash if you can: Berkeley Lab found loan-financed systems priced about $1.50/W above cash installs in 2025, which can add years to the payback.
Net metering and exports in California: Net Billing Tariff (NEM 3.0, since 2023-04-15 for PG&E/SCE/SDG&E): exports credited at hourly Avoided Cost Calculator values, locked 9 years by application-year vintage (NBT26 for 2026 applications). SDG&E NBT26 2026 file: simple 8,760-h average ~9.0¢/kWh but midday export hours mostly 0-6¢ (spring midday ~0¢); production-weighted ~3.7-4.6¢/kWh by IOU (Energy Toolbase: PG&E 3.9, SCE 4.6, SDG&E 3.7) vs ~30-33¢ retail. ACC Plus adder 2026: PG&E ~0.9¢, SCE ~1.6¢ (none SDG&E). CA Court of Appeal upheld NBT (Mar 2026); CA Supreme Court declined review 2026-06-10. Income-graduated Base Services Charge ($24.15/mo standard; SDG&E Oct 2025, SCE Nov 2025, PG&E Mar 2026) lowered volumetric rates ~5-7¢/kWh — solar avoids only the volumetric part.
Battery: a 13.5-kWh battery at the California average of $1,079/kWh adds $14,567 and shifts about 2,391 kWh a year from low-paid exports to your own use; payback becomes 13.4 years.
EnergySage's California page lists a 7.7-year payback. Its method is not fully published; ours uses EIA's Jan–Aug 2026 price, 40% self-use and the state's export credit, 3%/yr rate growth and 0.5%/yr panel aging, with no federal credit.
The full method, material data and tips are on the main solar payback calculator page.