About

Solar Payback Calculator is an educational utility from Andrew Flores / Nathan Management. Its purpose is to make a solar proposal easier to question: separate installation cost from incentives, separate self-consumption from exports, and show how changing an assumption changes the result. It is not an installer quote or a roof-specific engineering assessment.

What is here

• The calculator: enter your own cash price, year-one production, avoided import price, export credit, share of production used on site, recurring costs and incentive timing, and see the modelled cash-flow break-even.
• The state comparison: 51 rows (50 states and DC) run through the same benchmark, with the electricity price, sunlight input, production sensitivities and incentive-review status for each row, plus CSV, JSON and readable-model downloads.
• 17 state analyses that work through selected export-tariff and incentive questions; they are linked from the state comparison.
• 3 guides: The 2026 federal solar-credit cutoff: an IRS document audit; Net metering in 2026: rebuild the estimate from the actual tariff; Audit a solar quote with 12 months of utility bills.
• A downloadable quote worksheet for recording the documents behind a quote and what is still unknown.
• The methodology, which sets out the inputs, their sources and units, and the annual cash-flow calculation.

Observations are not assumptions

The benchmark electricity prices come from the U.S. Energy Information Administration's Electric Power Annual, Table 2.10. The stated data period belongs to the observed price, not to your future utility tariff. EIA explains that its average prices are not utility rates.

Installed dollars per watt, performance ratio, degradation, and future price escalation are modelling assumptions, and sunlight is NSRDB data for one location per state; none of it is a current installer-price survey or measured production at your address. The methodology separates these inputs from sourced observations and explains the cash-flow calculation and provenance limits. Neither a source link nor a precise-looking result makes an assumption a fact.

Benchmark versus your scenario

State comparisons use a common retail-value benchmark with no incentive deducted. That is useful for comparing identical assumptions, not for predicting a home's return. A household scenario needs your cash price, production estimate, avoidable import price, export credit and self-consumption share. The ZIP prefix only suggests a state; confirm the selection. It does not validate an address, identify a utility tariff or inspect a roof. The downloadable quote worksheethelps record the supporting documents and what is still unknown.

Who writes this

Who writes this - Andrew Flores, working alone, with AI assistance used for drafting and checking and never as a source.

Andrew Flores is responsible for the site.

What has been checked and when

• Electricity prices: all 51 values were rechecked against EIA Table 2.10 on 2026-09-24 (originally retrieved 2026-08-23).
• Sunlight: each row's input was requested from the NLR (formerly NREL) PVWatts v8 service on 2026-09-24. The shared request parameters, each state's location and the values PVWatts returned for it are published in state-insolation-pvwatts.json.
• Incentives: every row carries its own review date (latest 2026-09-24). 17 rows state a narrowly checked program term with a link to the administrator's record; the other 34 are marked unknown rather than filled in.
• Guides: each source box names the primary document and the date its quoted passage was checked.

These checks cover the stated inputs and source passages. They are not an engineering, tax or legal review of your project.

Advertising and data practices

This site includes Google AdSense code, which loads on every page. Google may use cookies and similar technologies to serve and measure ads, including on a visit where no ad is visible. The privacy policy explains what may be collected and how to opt out. Calculator estimates are not offers from advertisers.

Corrections

Use the contact page to report a calculation, source or wording problem. Include the affected URL, your non-sensitive inputs and the primary document supporting a correction. When a reported error is confirmed against the source record, the affected page or data row is corrected.