In Louisiana, a 7.5-kW system for an average home costs about $17,279 after incentives in 2026, saves about $938 in the first year and pays back in 15.4 years.
| Item | Amount |
|---|---|
| Solar, 7.48 kW × $2.31/W | $17,279 |
| Federal credit (0%) | $0 |
| Net cost | $17,279 |
| Scenario | Net cost | Year-1 savings | Payback | 25-yr net |
|---|---|---|---|---|
| State averages (above) | $17,279 | $938 | 15.4 yr | $14,689 |
| Rates rise 5.6%/yr (2020–25 pace) | $17,279 | $938 | 13.4 yr | $27,613 |
| Rates stay flat | $17,279 | $938 | 19.3 yr | $4,810 |
| Survey price $3.6/W (LBNL) | $26,928 | $938 | 21.9 yr | $5,040 |
| Add 13.5-kWh battery | $38,690 | $1,232 | 23.2 yr | $4,006 |
| Size to 100% of use instead | $24,394 | $1,324 | 15.4 yr | $20,737 |
Verdict: at average Louisiana numbers, solar is a marginal investment in 2026 — payback takes 15.4 years, leaving you $14,689 ahead after 25 years. The main reasons: cheap power (the 5th-lowest price of 51), which caps what each kWh saves; export credits below retail (exports earn ~45% of retail), so only the solar you use yourself earns full value. Get at least three quotes: every $0.25/W you shave off the price moves payback by roughly a year or more here.
Net metering and exports in Louisiana: Net billing for most utilities; exports credited at < half retail.
Battery: a 13.5-kWh battery at the Louisiana average of $1,586/kWh adds $21,411 and shifts about 4,435 kWh a year from low-paid exports to your own use; payback becomes 23.2 years.
EnergySage's Louisiana page lists a 14.8-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.