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Solar in California
At 33.61¢ per kWh and 1675 kWh of production per kW each year, a household paying $200 a month needs a 4.01 kW system. Paid in cash, it returns its $9,938 cost in 8.9 yr.
Two prices, two answers
Payback 8.9 yr — at competitive quoted prices ($2.48/W, EnergySage 2026): net cost $9,938, 25-year net $22,024.
Payback 15.4 yr — at typical reported prices ($4.20/W, LBNL 2023): net cost $16,831, 25-year net $15,131.
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 | 3,142 kWh | 1.88 kW | 5 | $4,652 | 10.3 yr | $7,359 | −$190 |
| $150/mo | 4,927 kWh | 2.94 kW | 8 | $7,295 | 9.3 yr | $14,692 | −$298 |
| $200/mo | 6,712 kWh | 4.01 kW | 11 | $9,938 | 8.9 yr | $22,024 | −$406 |
| $300/mo | 10,283 kWh | 6.14 kW | 16 | $15,224 | 8.5 yr | $36,695 | −$622 |
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 | $22,024 | $9,938 | $1,023 | 8.9 yr | $0 |
| Loan $77/mo · 6.99% APR · 20 yr | $13,484 | $0 | $99 | cash-flow neutral from year 1 (+$99/yr) | $0 |
| Lease / PPA | −$15,636 | $0 | −$406 | 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 | 33.61¢/kWh | U.S. EIA API v2, electricity/retail-sales, residential sector, 2026-07 |
| 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 · 20% | Net Billing Tariff, adopted in CPUC Decision D.22-12-056 and applied to new customers from 15 April 2023. Exports are compensated at Avoided Cost Calculator values, which the CPUC describes as usually lower than retail rates but able to rise above them on late summer evenings; the rate differs every hour. NEM 2.0 customers keep their tariff for 20 years from interconnection. The CPUC states the mechanism but publishes no single average export price. Independent 2026 summaries put the average export credit at roughly $0.05-$0.08/kWh against a California residential retail rate of 34.74 c/kWh (EIA 2026-06), i.e. 0.14-0.23. The record uses 0.20. Replace it with a utility-published average when one is available. Follows: PG&E, SCE and SDG&E (the three investor-owned utilities the tariff covers) Source, read 2026-09-05. |
| 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.