About

BillToSolar turns a power bill into a first-pass solar plan: panel count, system size, battery, cost, payback and a parts list. It is built for homeowners and DIY buyers who want a number before they call an installer.

How it works

The PDF is read in your browser and never uploaded; see the privacy page. The sizing formulas are shown on each calculator page with their constants, so you can check the arithmetic yourself.

Where the numbers come from

Electricity use and prices are EIA 2024 residential state averages. Solar yield per kilowatt and winter sun hours come from NREL PVWatts v8 runs, as compiled by TheGreenWatt and checked on 2026-11-03. Cost figures carry their source and date. All of it is a planning estimate.

How it makes money

The calculator is free. Some parts links are affiliate links, and a paid full plan is planned. See the affiliate disclosure.

Contact

support@billtosolar.com