The calculation model
Energy is measured in kilowatt-hours. For stable loads, we convert watts to kilowatts and multiply by active runtime. Cost then equals energy multiplied by the user’s marginal electricity rate.
Weekly schedules use 52 weeks divided across 12 months, avoiding the common assumption that every month has exactly four weeks.
Provenance classes
- Estimated: entered or inferred without direct observation.
- Label-derived: taken from a rating plate or technical document.
- Measured: observed through a compatible meter, charger, or utility dataset.
- Outcome-verified: measured before and after a documented change.
Uncertainty
PowerCost Lab presents planning ranges where duty cycle, charging loss, or usage pattern can materially change results. The range is not a statistical confidence interval in the first version; it is a transparent sensitivity band around the user’s scenario.
The future Energy Cost Graph
Explicitly contributed measurements may improve cohort benchmarks and estimate calibration. A cohort holds device class, grid convention, climate context, and rated-power band constant. Only approved observations with privately verified meter evidence can enter a published cohort. Contributions are stored without names, email addresses, or exact household addresses.
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