How What Is Solar Worth? works
Transparent estimates, with the limits included.
What Is Solar Worth? separates reviewed utility mechanics from representative assumptions, and keeps unknowns visible instead of filling them with false precision.
Production and location
PVWatts/NLR models solar production from a Census ZCTA representative location. A ZIP area is useful for screening, but it is not an exact roof survey. Roof direction, pitch, and manually described shading affect the estimate.
System size and timing
Energy-match sizing compares annual generation with annual household use and reports whole-panel candidates without calling one “recommended.” A collapsed NREL ResStock End-Use Load Profile represents broad seasonal, weekday/weekend, and time-of-day behavior; it is not measured household data.
Energy versus bill offset
Energy offset compares annual kWh. Bill offset estimates avoided utility cost after imports, exports, fixed charges, and the applicable tariff treatment. They can differ substantially.
Basic Estimate
When no exact verified tariff is available, the nationwide Basic Estimate uses the homeowner's annual spending and usage plus representative timing. Unknown export compensation is shown as lower and upper scenarios, never a hidden average.
Verified utility models
When an exact published configuration matches, first-year billing uses that reviewed package. Long-term verified results identify whether future components are current, officially scheduled, or scenario-projected. They never present a scenario as a utility guarantee.
Long-term value
Annual projections re-run production, load, energy flow, and billing each year. MVP assumptions include 0.5% annual degradation, 2.5% import escalation where applicable, a $30/kW-year maintenance reserve, a 20-year primary horizon, and a separate 25-year sensitivity.
Thresholds and financing
Cash break-even, the 10-year simple-payback target, and the 5% hurdle-rate target are distinct criteria. Financing premium, interest, and scheduled outlay are analyzed separately from cash project-price thresholds.
Quote review
Quote normalization keeps solar-only cash price, adders, financing, production claims, panels, and installer incentive claims distinct. Comparisons use the quoted system capacity; findings are factual checks, not installer ratings.
Confidence and provenance
Production and bill confidence are component-specific. Sources include U.S. Census ZCTA data, PVWatts/NLR, NREL ResStock EULP, and reviewed utility or regulator material where applicable. The active assumption policy is solar-value-mvp@1.0.0; result snapshots preserve their calculation context.