Last reviewed: August 4, 2026
Calculation standards
Calculator results are produced from the values shown on the page. We display the core formula and label statewide or national rate presets as planning estimates. We encourage visitors to use numbers from their own appliance labels and utility bills.
Sources and updates
Guides prioritize primary sources such as U.S. government energy agencies, utility rate schedules, building codes, and manufacturer documentation. Dates and assumptions are reviewed when a guide or data set is updated.
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Corrections
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