Sources
Every important number should have a source or be clearly labeled as a planning assumption. SolarCalcNow prioritizes transparent gross estimates over unverified net-cost claims.
Source stack
Production evidence: California has a saved full PVWatts response; eight states have successful API yields recorded to two decimals. Colorado, Illinois and Pennsylvania retain explicit author assumptions. The download distinguishes these evidence levels.
$0.3474/kWh
34.74 ¢/kWh
EIA Table 5.6.A, June 2026 residential column; published August 26, 2026. Divide the published cents/kWh by 100. This preliminary statewide average is a fallback, not your utility tariff. Use your bill's energy-only rate; fixed charges remain payable.
1,595.2 kWh/kW/year
kWh/kW/year
PVWatts V8 typical-weather model at an author-selected reference point in the state: 4 kW DC, roof mount, 20° tilt, 180° azimuth, 14% system losses. Annual AC kWh ÷ 4 gives kWh/kW/year. Losses are already included and are not deducted again. Neither a statewide average nor a ZIP or roof survey. Shade and ±10% production bounds are separate author scenarios.
$1.98–$2.98/W
$2.48/W × 0.8…1.2
EnergySage's state marketplace average, table updated August 28, 2026. We calculate an author-selected range of average × 0.8 to average × 1.2, rounded to cents/W. This ±20% scenario is not an observed price distribution or confidence interval. Cash solar only, before incentives; compare like-for-like local quotes.
State residential electricity rate assumptions.
National electricity price context.
Reference calculator for PV production assumptions and user-facing solar production context.
Saved PVWatts AC outputs and an optional live model at the same state reference points. ZIP is not geocoded; modeled system losses are already included.
State, utility, and local incentive verification before incentives are used in net-cost math.
Roof, ownership and equipment context. Older tax-credit passages are not used for current eligibility; current IRS guidance takes precedence.
Neutral PV system component context for modules, inverters, storage, and mounting.
Federal residential clean energy credit status review.
Raw state marketplace averages; the displayed plus or minus 20% range is a SolarCalcNow scenario, not an observed quote interval.
Source update cadence
Solar assumptions can go stale quickly. These review rules keep source updates explicit before rates, production, incentives, or localized claims are used in estimates.
Source freshness changelog
2026-09-04
Updated twelve EIA rates and cost assumptions, and recorded production evidence with explicit coverage limits; added source-backed utility and incentive summaries in six languages.
System losses are counted once. ZIP no longer implies exact location. Worked bills, equipment comparisons and 108 reproducible scenarios expose inputs and limits.
2026-07-22
Migrated the calculator, API documentation, and server endpoint from retired NREL hosts to the current NLR domains.
Public source links resolve again, and the optional ZIP-level provider is ready for the current API host without changing fallback behavior.
2026-07-16
Made direct solar use, export allocation, annual energy-charge cap, panel degradation, and battery conversion losses explicit in the planning models.
Savings and backup results are more conservative and auditable; legacy report URLs and saved scenarios keep working through schema defaults.
2026-07-10
Added a time-sensitive official status update after the Maryland Energy Administration confirmed FY2026 Bridge Fund applications are closed to new applicants.
The update is review-only and excluded from all net-cost and payback calculations because the program is closed and eligibility is highly specific.
2026-07-10
Refreshed all 12 supported state residential planning rates from EIA Electric Power Monthly Table 5.6.A April 2026 release.
Calculator and state planning pages now use April 2026 EIA preliminary residential prices; no incentive or net-cost treatment changed.
2026-07-03
Quarterly review against EIA Electric Power Monthly Table 5.6.A March 2026 release.
No state residential rate changes applied; cadence dates updated on /sources.
2026-06-29
Added typed source cadence for solar equipment category and future product records.
Equipment product pages stay unpublished until datasheet, warranty, source-review, and disclosure fields pass.
2026-06-27
Added a source gate for future utility, city, and expanded state pages.
Local guidance requires source-backed rate, export-value and incentive information with review dates.
2026-06-28
Added typed gates for future utility tariff and battery program records.
Future utility or battery records stay unpublished until source, review, confidence, fallback, and eligibility fields pass.
2026-06-27
Confirmed PVWatts source naming and URLs on the current NREL domain.
The public source page points users to the live NREL calculator and NREL API documentation.
2026-06-25
Moved federal credit language to reviewed IRS source status and conservative no-tax-advice wording.
New 2026 estimates avoid unsupported federal-credit net-cost claims.
2026-06-24
Added recurring review cadence for rates, production assumptions, incentives, cost benchmarks, and localized copy.
Source-sensitive claims have an auditable owner workflow before automation is added.
Use the source list to understand the assumptions, then generate an estimate and compare any quote against the same baseline.