The original Geostellar built its reputation on the Solar Index — a computation of solar potential for individual parcels, combining irradiance data, 3D shading models, local electricity rates, and incentives into a single "should you go solar" readout. It earned coverage from national press and energy.gov because it answered the right question: not "how good are panels," but "how good is your roof."
What we kept
The successor is the Solar Savings Calculator, and it keeps the Index's philosophy with a humbler method: instead of claiming parcel-level precision, it takes the two numbers you actually know — your monthly bill and your rough location profile — and computes system size, cost, savings, and payback from documented national baselines you can override. Every assumption is editable and published on the methodology page.
Why the humbler method
Parcel-scale modeling is now table stakes inside installer quoting tools, and the free NREL PVWatts covers address-level production estimates better than any consumer site should re-implement. Where consumers are underserved is the finance layer — honest payback, financing comparison, and incentive math without a sales agenda. That's the gap this site's calculator suite now aims at.