Disclaimer

Disclaimer revised September 24, 2026.

The state benchmark is not your household scenario

The state comparison uses the common assumptions below. Editable calculator scenarios and the guides' labelled illustrations can use different inputs. A statewide comparison is not an address-specific production forecast, utility tariff, installer quote, or financial recommendation.

• Assumed system: 7 kW DC residential array.
• Assumed installed cost: $3.20 per DC watt, or $22,400 for the benchmark system before incentives. This is not an observed market price.
• Estimated production: system kW × the state's one-location NSRDB sunlight input × 365 × an assumed 0.78 performance ratio. The sunlight input is not a roof measurement; see the provenance limits in methodology.
• Observed electricity price: Calendar year 2024 annual average, from EIA Table 2.10. This average is not a tariff or a forecast.
• Assumed degradation: 0.5% per year, compounding.
• Assumed price escalation: 3.0% per year. This is a sensitivity choice, not a promise about future electricity prices. Compare a zero-escalation case.
• Horizon: 25 years. No break-even within that horizon is different from never breaking even; the model does not extrapolate a later date.
• Incentives: none deducted from the state benchmark. A listed program does not establish eligibility, a usable credit, an available allocation, or a payment date.
• Energy value: the benchmark values all production at the state-average retail price. That can overvalue exports and charges solar does not avoid. A household scenario should separate the avoidable import price, export credit and self-consumption share.

What a custom scenario can and cannot establish

Enter a cash installation price and a roof-specific first-year production estimate where available. Use an avoidable import price rather than dividing the whole bill by usage if fixed charges would remain. The simplified annual model applies your self-consumption share and export price; it is not an hourly tariff simulation. A different system size need not change payback when cost and production scale equally and all other assumptions remain fixed.

The "Assumed recurring solar cost" field is for incremental solar costs such as added maintenance or a new solar-specific charge. Do not subtract an existing customer charge again after already excluding it from the avoided import price. Add recurring incentives only for the stated duration; record delayed receipts in their expected year rather than subtracting them from day-one cost. The "Assumed upfront cash rebate" field is deducted from the initial cost only; it is not a tax-liability or carryforward calculation. A state tax credit belongs in the "Assumed one-time delayed incentive" and "Delayed receipt year" fields, in the year you expect to receive it. Never enter the same benefit both upfront and as a later receipt, or deduct a rebate already included in the cash quote.

Financing interest, loan fees, discounting, resale value, future tariff changes, incentive taxes, battery dispatch, hourly load matching, export caps, minimum bills and demand charges are not fully simulated. Including a battery's price alone does not model its operation or benefits. Cash-flow estimates are not an investment return calculation. Actual results can differ materially; no statistical error band has been established for this tool.

The federal residential credit

The IRS Residential Clean Energy Credit page excludes property placed in service after December 31, 2025. The calculator does not automatically apply a federal residential Section 25D credit to a new 2026 installation. Unused qualifying prior credit is a separate carryforward question, not a new installation discount. The federal-credit guide links the IRS completion-timing FAQ. Confirm your own tax facts with a qualified professional; the site does not determine eligibility.

Source provenance and corrections

The benchmark's rate period is Calendar year 2024 annual average. Its source is EIA Electric Power Annual, Table 2.10. EIA distinguishes these averages from utility rates. The methodology page sets out the inputs, their sources and units, and the annual cash-flow calculation. Cost and price-escalation assumptions must not be read as verified current market or tariff observations, and the one-location sunlight input is not a measurement of your roof.

Inputs are not updated on a fixed schedule. Each state row in the downloadable input file records the date its electricity price was verified and the date its incentive record was last reviewed. Where a page shows a "checked" date, it covers only the quoted source passage. Before relying on an incentive or export rate, check the administrator, customer class, effective date and program status. Report a specific error through contact with the source record.

Advertising and site operation

The site may display advertising served by Google, and Google's advertising code may process data even when no ad is visible; see the privacy policy for data practices and your choices. Advertising is not verification of an installer, a product, or this model's accuracy.

Before deciding

Compare itemized cash-price proposals, roof-specific production reports and your utility's applicable tariff. Use the quote worksheet to separate documents from assumptions and test lower production, lower export value, no incentives and added costs. Confirm roof, electrical, permit and tax questions with the relevant qualified professionals. Do not buy or finance a system using this site alone.

The site is provided "as is" without warranties of accuracy, completeness or fitness for a particular purpose. See the Terms of Use.