Energy decisions, backed by numbers.
Most solar calculators are lead-generation forms with arithmetic attached. This one publishes its formulas, cites every input, and tells you plainly what it does not know.
The thing most calculators still get wrong about 2026
The 30% residential credit under 25D expired on 31 December 2025. If you buy a system with cash or a loan in 2026, your federal credit is 0% — nothing.
But the credit did not disappear from the industry. A leasing or PPA company that owns the panels on your roof still claims 30% under IRC 48E. The money still exists. It simply stopped being yours.
Why a residential array gets the full rate rather than the 6% base: One-megawatt exception: a facility with maximum net output under 1 MW AC is entitled to the increased credit rate without meeting prevailing-wage and apprenticeship requirements (26 CFR 1.45Y-3). Residential arrays are 5-15 kW, far under the threshold.
What that change costs a real buyer
The same house in Austin, Texas, on a $200/month electricity bill — a 9.54 kW system either way:
| Buying with cash | In 2025 | In 2026 | Change |
|---|---|---|---|
| Federal credit | $6,356 | $0 | −$6,356 |
| Net cost | $14,831 | $21,187 | +$6,356 |
| Payback | 7.1 yr | 9.8 yr | +2.7 yr |
| 25-year net | $47,436 | $41,080 | −$6,356 |
Solar in Texas still pays for itself. It now takes 2.7 years longer to do it.
Run it for your own bill
Pick a state, type what you pay each month, and move the assumptions you disagree with. The calculator runs the identical engine that built the table above.
States we cover
Ranked by residential electricity price — the input that matters most, ahead of sunshine.
- California34.74¢
- Massachusetts29.61¢
- New York29.49¢
- New Jersey24.95¢
- Connecticut24.32¢
- Maryland21.84¢
- Pennsylvania21.73¢
- Illinois19.89¢
- Texas15.94¢
- Arizona15.18¢
- Florida15.1¢
The guides
Long-form, answer-first, every number computed at build time and every claim cited with the date it was read.
- The federal solar tax credit in 2026
Gone for buyers, still 30% for leases. What ended, what survives, computed and cited.
- Lease, loan or cash for solar in 2026
The three ways to pay, run on the same house, year by year, in every state we publish.
- What solar costs in 2026
Two price bases, by state and by bill, and why they are 60% apart.
- Solar payback in 2026
How it is computed, what moves it, and the state ranking - rate beats sunshine.
- State solar incentives in 2026
Which states still pay a buyer, what they pay, and where there is nothing - each from its own source.
- Is a home battery worth it in 2026?
Where storage changes the maths and where it does not, with the assumptions in the open.
How this site is built
- Federal policy is data, versioned by year — never a constant in the code.
- Every record carries a
sourceand averified_ondate. - A value we have not verified is
null, and the page says so. We never invent a number. - One calculation module feeds both these pages and the interactive calculator, so the two can never disagree.