Data
Solar Economics Index
The 11 states we publish, ranked by how long a rooftop solar system takes to repay itself on one identical house. In October 2026 that runs from 5.7 yr in New York to 13.4 yr in Arizona. Every figure is computed from published data by one engine, and every input is downloadable.
Edition 2026-10, cut 14 October 2026 and frozen. Next edition November 2026. Permanent link to this edition: /data/solar-economics-index/2026-10/.
The ranking
11 states, ranked by the year a cash purchase repays itself. One reference house in every state: a $200 monthly electricity bill, statewide averages, 2026 federal policy, a system sized to cover that household's own use. Cut 2026-10-14 and frozen.
| # | State | Payback | Rate | Installed | Yield | System | Net cost | Year 1 | 25-year net |
|---|---|---|---|---|---|---|---|---|---|
| 1 | New York | 5.7 yr | 29.9¢ | $2.76/W | 1291 | 5.84 kW | $12,098 | $2,027 | $52,516 |
| 2 | New Jersey | 6.1 yr | 25.19¢ | $2.58/W | 1305 | 6.86 kW | $17,706 | $2,796 | $58,881 |
| 3 | Massachusetts | 6.9 yr | 30.49¢ | $2.91/W | 1302 | 5.68 kW | $15,537 | $2,106 | $51,059 |
| 4 | Illinois | 8.5 yr | 19.22¢ | $2.98/W | 1308 | 8.97 kW | $26,742 | $2,560 | $31,510 |
| 5 | Pennsylvania | 8.6 yr | 21.72¢ | $2.58/W | 1359 | 7.64 kW | $19,719 | $2,106 | $46,877 |
| 6 | Maryland | 8.7 yr | 21.41¢ | $2.62/W | 1392 | 7.57 kW | $19,833 | $2,106 | $46,763 |
| 7 | California | 8.9 yr | 33.61¢ | $2.48/W | 1677 | 4 kW | $9,926 | $1,023 | $22,036 |
| 8 | Florida | 9 yr | 15.03¢ | $2.12/W | 1544 | 9.72 kW | $20,610 | $2,106 | $45,986 |
| 9 | Connecticut | 10.3 yr | 24.16¢ | $2.72/W | 1252 | 7.46 kW | $20,286 | $1,731 | $37,467 |
| 10 | Texas | 11.3 yr | 15.88¢ | $2.22/W | 1506 | 9.43 kW | $20,942 | $1,700 | $32,666 |
| 11 | Arizona | 13.4 yr | 15.38¢ | $2.21/W | 1755 | 8.36 kW | $17,471 | $1,253 | $21,851 |
Payback in years on a cash purchase, after maintenance and an inverter replacement. Rate: cents per kilowatt-hour. Installed: dollars per watt before incentives, on the quoted basis. Yield: kilowatt-hours per kilowatt per year. Every input is in the data index, with the source it was read from.
One sentence per state
Written at the cut and stored with the edition, so a sentence quoted from this page says the same thing for ever. Take any of them.
- New York ranks 1st of 11 for solar payback in October 2026, at 5.7 years.
- New Jersey ranks 2nd of 11 for solar payback in October 2026, at 6.1 years.
- Massachusetts ranks 3rd of 11 for solar payback in October 2026, at 6.9 years.
- Illinois ranks 4th of 11 for solar payback in October 2026, at 8.5 years.
- Pennsylvania ranks 5th of 11 for solar payback in October 2026, at 8.6 years.
- Maryland ranks 6th of 11 for solar payback in October 2026, at 8.7 years.
- California ranks 7th of 11 for solar payback in October 2026, at 8.9 years.
- Florida ranks 8th of 11 for solar payback in October 2026, at 9 years.
- Connecticut ranks 9th of 11 for solar payback in October 2026, at 10.3 years.
- Texas ranks 10th of 11 for solar payback in October 2026, at 11.3 years.
- Arizona ranks 11th of 11 for solar payback in October 2026, at 13.4 years.
What this edition was computed from
| Electricity prices | EIA 2026-07, read 2026-10-14 |
| Solar yield | PVWatts v8 (verified), read 2026-09-05 |
| Installed cost | EnergySage 2026, read 2026-09-05 |
| Export rules | read 2026-09-05 |
| State incentives | read 2026-09-05 |
| Federal policy | 2026, read 2026-09-05 |
| Modelling assumptions | set 2026-09-04 |
Each of those is a file you can download whole, with every record and its source, from the data index. The formulas that consume them are on the methodology page.
What moved since last month
Against September 2026: 8 of 11 states moved, 3 held their position.
- Pennsylvania moved up 2 places, from 7th to 5th. Nothing about Pennsylvania changed; Maryland and California crossed it.
- California moved down 1 place, from 6th to 7th, with payback lengthening from 8.6 to 8.9 years. The cause: the electricity rate moved from 34.74¢/kWh to 33.61¢/kWh.
- Maryland moved down 1 place, from 5th to 6th, with payback lengthening from 8.5 to 8.7 years. The cause: the electricity rate moved from 21.84¢/kWh to 21.41¢/kWh.
- Illinois held 4th, with payback lengthening from 8.2 to 8.5 years. The cause: the electricity rate moved from 19.89¢/kWh to 19.22¢/kWh; the state incentives a buyer receives moved from $13,271 to $13,734.
- Texas held 10th, with payback lengthening from 11.1 to 11.3 years. The cause: the electricity rate moved from 15.94¢/kWh to 15.88¢/kWh.
- Massachusetts held 3rd, with payback shortening from 7.1 to 6.9 years. The cause: the electricity rate moved from 29.61¢/kWh to 30.49¢/kWh.
- Florida held 8th, with payback lengthening from 8.9 to 9 years. The cause: the electricity rate moved from 15.10¢/kWh to 15.03¢/kWh.
- Arizona held 11th, with payback shortening from 13.5 to 13.4 years. The cause: the electricity rate moved from 15.18¢/kWh to 15.38¢/kWh.
Citing it
Free to quote, with a link. Two things worth knowing before you do:
- Cite the dated edition, not this page
- This URL always shows the newest edition, so what it says will change. The dated one never does: solar-economics-index/2026-10/ will say in five years exactly what it says today, with the same figures and the same sentences.
- The sentence per state is written for you
- Each is generated at the cut from the row it describes, so it cannot drift from the table above it. Copy one whole. If you would rather compute your own line, the CSV has every field the sentence was built from.
- What the ranking is not
- It is not a ranking of states by how much sun they get, and it is not advice about your own roof. It is one house, modelled identically everywhere, so the comparison measures policy and price rather than the household. Your own payback depends on your bill, your roof and your utility — work it out.
How it is built
- One house, eleven states. The same monthly bill and the same modelling assumptions everywhere, with the system sized to that household's own use. Nothing varies but the state.
- Statewide records only. No city figures, so the ranking is not decided by which towns we happen to hold.
- Only states we can stand behind. A state needs its own electricity rate, yield, installed cost and export rule before it is ranked. A missing record keeps a state out; it never falls back to a national average.
- Cut once, then frozen. The edition is computed on the day it is cut and written to a file that is never rewritten. Correcting a published edition means publishing the correction, not editing the archive.
- Refuses to cut on a broken record. If any state carries an error flag, no edition is produced at all.
The archive
Every edition ever published, kept at its own permanent URL.
- October 2026
11 states, cut 2026-10-14. New York first at 5.7 years. CSV
- September 2026
11 states, cut 2026-09-06. New York first at 5.7 years. CSV
Published 6 September 2026. Last verified 14 October 2026. A figure here that looks wrong is the mail we most want: tell us, and we publish corrections. The formulas that consume these records are on the methodology page.