Source priority
We prefer the U.S. Energy Information Administration for electricity-rate context, the U.S. Department of Energy for energy-use methodology, ENERGY STAR for appliance efficiency information, the Environmental Protection Agency where appropriate, the National Renewable Energy Laboratory for solar and storage methods, and manufacturer specifications for model-specific performance.
What each calculator records
Calculator definitions record a source name, direct link, publication or access date, geographic scope, last-reviewed date, and explanation of how the source informs the calculation. Defaults are never presented as a visitor’s exact local rate or equipment specification.
Update method
Reviewed defaults live in the calculator registry so changes are version-controlled and tested. Electricity-rate context should be reviewed at least quarterly; source links, appliance guidance, and methodology should be reviewed at least annually or sooner when a source changes materially.
Corrections
Substantive reports are checked against an authoritative or primary source. Confirmed errors are corrected promptly and calculations are re-tested before publication.
Current scope
The first release uses U.S.-focused sources and U.S. dollars. Visitors outside the United States can use custom numeric inputs, but local tariffs, taxes, currencies, and regulations are not fully modeled.