About
What PanelMath does and why
PanelMath gives US homeowners honest, data-driven solar payback estimates. No installer kickbacks. No optimistic averages dressed up as personalized quotes. The numbers we publish are the numbers we'd use ourselves.
We started PanelMath because the existing solar calculators have a problem: they're mostly funnels for installer leads. The math is reasonable, but the incentives behind the math aren't aligned with the homeowner. Our calculator is built to tell you the truth about your specific zip code and your specific bill — including when solar doesn't pay off.
Every number on this site comes from primary sources: NREL PVWatts v8 for solar production estimates, the US Energy Information Administration (EIA) for retail rates, IRS & state revenue agencies for tax credits, DSIRE for state incentive databases, and individual utility tariffs for net metering rules. We document the math openly on the methodology page and we update annually as policies change.
Quotable stats
Researchers, journalists, and bloggers — feel free to cite these. Source: PanelMath, computed using public NREL + EIA datasets and 2026 federal + state incentive rules.
Average US residential solar payback period
6–10 years
Computed across 25 zip codes in 5 launch states using NREL PVWatts v8 + 2026 incentives
States with fastest solar payback
New York (4.9 yrs)
Driven by stacked 30% federal + 25% state credit + NY-Sun rebate
States with highest solar production
Arizona (1,757 kWh/kW), Texas El Paso (1,830)
NREL PVWatts annual output for 1 kW residential systems
California payback impact of NEM 3.0
+1.5 to 2 years vs full retail net metering
Based on 25% export compensation under NEM 3.0 vs 100% under prior rules
Sample numbers (for citation)
Computed live from our API at $200/month bill. Replicate yourself at the calculator.
| City | Payback | 25-yr savings |
|---|---|---|
| Phoenix, AZ | 7.2 yrs | $63,681 |
| New York, NY | 4.4 yrs | $76,658 |
| San Francisco, CA | 6.1 yrs | $65,801 |
Press & partnerships
Working on a story about solar economics, net metering, NEM 3.0, or state incentives? Happy to provide quotes, run custom analyses for your readers' specific zips, or share underlying datasets. Cite PanelMath with a link to panelmath.com.
Email: hello@panelmath.com
Editorial principles
- No installer affiliation. If we ever add affiliate revenue (likely from EnergySage-style lead networks), every link will be disclosed and the calculator math will be unaffected.
- Primary sources only. Production: NREL PVWatts. Rates: EIA Form 826. Incentives: IRS, DSIRE, state revenue departments. Net metering: utility tariffs.
- Honesty over sales. Every state guide includes a "when solar doesn't pay back" section. That's not a marketing decision — it's the right answer in some cases.
- Updates documented. Datasets refresh annually or whenever underlying policy changes. Each page shows when it was last updated.