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Solar in California
At 34.74¢ per kWh and 1675 kWh of production per kW each year, a household paying $200 a month needs a 3.88 kW system. Paid in cash, it returns its $9,615 cost in 8.1 yr.
What we don't know yet
Two prices, two answers
Payback 8.1 yr — at competitive quoted prices ($2.48/W, EnergySage 2026): net cost $9,615, 25-year net $24,513.
Payback 14.3 yr — at typical reported prices ($4.20/W, LBNL 2023): net cost $16,283, 25-year net $17,845.
The gap is methodology, not staleness: the first what you get if you shop around for competitive quotes; the second what the average buyer actually paid, as recorded in permit and incentive data. Every table below uses quoted prices. Why we show both.
By monthly bill
| Your bill | Use / yr | System | Panels | Net cost | Payback | 25-yr net (cash) | Lease, year 1 |
|---|---|---|---|---|---|---|---|
| $100/mo | 3,040 kWh | 1.81 kW | 5 | $4,501 | 9.3 yr | $8,522 | −$158 |
| $150/mo | 4,767 kWh | 2.85 kW | 8 | $7,058 | 8.5 yr | $16,518 | −$248 |
| $200/mo | 6,494 kWh | 3.88 kW | 10 | $9,615 | 8.1 yr | $24,513 | −$338 |
| $300/mo | 9,948 kWh | 5.94 kW | 15 | $14,729 | 7.8 yr | $40,508 | −$518 |
Cash, loan or lease — at $200 a month
| How you pay | 25-year net | Upfront | Year 1 | Payback / cash flow | Federal credit to you |
|---|---|---|---|---|---|
| Cash | $24,513 | $9,615 | $1,091 | 8.1 yr | $0 |
| Loan $74/mo · 6.99% APR · 20 yr | $16,251 | $0 | $197 | cash-flow neutral from year 1 (+$197/yr) | $0 |
| Lease / PPA | −$13,471 | $0 | −$338 | never | $0 |
The 30% federal credit goes to the system owner, not to you. It is reflected in the rate you are offered. The owner claims it at 30% under IRC 48E.
The inputs, and where they came from
| Input | Value | Source |
|---|---|---|
| Residential electricity rate | 34.74¢/kWh | U.S. EIA API v2, electricity/retail-sales, residential sector, 2026-06 |
| Specific yield | 1675 kWh/kW/yr | NLR (formerly NREL) PVWatts v8 API, 1 kW reference system (city:san-diego-ca) |
| Installed cost | $2.48/W | EnergySage Marketplace real-quote average, as of Sep 2026; page updated 2026-08-28 · LBNL Tracking the Sun 2023 median: $4.2/W, reference only |
| Export compensation | net billing, export credited below retail · 25% | NEM 3.0 / net billing — not yet verified against the tariff |
| Federal credit, purchase | 0% | IRC 25D (expired) |
| Federal credit, third-party owner | 30% | IRC 48E (Clean Electricity Investment Credit) |
| State incentives | $0 | No upfront statewide credit or rebate for a typical owner-occupier (verified) |
City-level production on file for: San Diego. The figures above use San Diego.