What this site uses
- Production: the PVWatts v8 model from the National Laboratory of the Rockies (NLR, formerly NREL), run for a generic 1 kW array at each city: fixed roof mount, 20 degree tilt, due south, standard modules, 14 percent losses, typical-year weather.
- Prices: the federal EIA-861 survey and EIA state averages. They are class-wide averages (revenue divided by kWh sold), not a quote.
- Rate plans: the OpenEI Utility Rate Database, which is crowd-maintained and can be out of date, so pages call them plans on file.
- Buyback and law: primary pages only, with a date. Anything not confirmed is listed as excluded.
The full source list with required notices is on the sources and disclosures page.
How it relates to other tools
| Tool | What it says it does | What it does not cover, per its own materials |
|---|---|---|
| PVWatts (NLR) | "Estimates the energy production of grid-connected photovoltaic (PV) energy systems throughout the world." (pvwatts.nlr.gov) | It is a production model; it does not price power under a Texas buyback plan. |
| Google Project Sunroof | Estimates solar savings for a roof; its methodology note lists a 20-year life and a 2.2 percent yearly price increase (methodology). | The same note says it "supports only certain US locations at this time" and "does not calculate values related to excess energy production". Whether the service is currently running was not confirmed. |
| EnergySage | "Gathering custom solar quotes for you from our network of pre-screened installers" (EnergySage). | It is a quote marketplace; Rate & Roof does not collect or rank installer quotes. |
What Rate & Roof does differently
- It starts from one stored PVWatts run per Texas city, so a calculator result can be traced to the number on that city's page.
- It prices exports under Texas buyback structures, including a credit on production like Austin Energy's, which the production tools above do not.
- Every assumption is shown and editable, and every page lists its sources with dates.
- It has no installer network. If a marketplace link ever appears, it is labeled and carries a disclosure.
Try it in the payback calculator. It is an estimate, not a quote, and no substitute for a measured design from an installer.
This page is general information, not advice for your situation.