Reading Proposals

What a solar proposal must state, which assumptions shorten payback on paper, and how to test whether a production guarantee obligates anything.

Reading Proposals August 21, 2026 The 12 Items a Solar Proposal Must Show, and Why A proposal quoting 11,900 kWh from 8.40 kW claims 1,417 kWh per kW-DC. Twelve items decide whether that number survives contact with your own tariff sheet. 10 min read

About this section

Three quotes for the same roof came back with three different payback figures — seven years, nine, and fourteen. Priya Raghunathan rebuilt all three in a spreadsheet to find where they diverged, and the spreadsheet turned into this site. She does not work in the energy industry and has never sold, financed, or installed a system. Every number here is traced to a utility tariff sheet, a regulator's decision, or a published standard, and the arithmetic is written out so you can redo it on your own bill.

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Every guide cites the agency, statute, or document it was checked against, and carries the date it was checked. Rules change — if something here is out of date, tell us and it gets corrected.