Build a monthly baseline
Track electricity kWh, gas therms and water gallons separately from dollars. Include billing days and household occupancy so the series remains interpretable.
Annotate the causes
Mark heat waves, freezes, travel, guests, EV charging and irrigation. The goal is not a perfect model; it is a record that makes large changes explainable.
- Usage per day
- Effective variable rate
- Fixed charges
- Weather and occupancy note
Change one thing at a time
After identifying the biggest flexible load, test one operating change and compare the next normalized period. Avoid attributing an entire seasonal swing to a small device.
Editorial standard
This guide explains general billing math. Utility tariffs and local rules control your actual charges. Sources and update practices are documented in our methodology.
Read the methodology →