Energy cost estimating assumptions
How to prepare kWh, usage and tariff assumptions before using an Australian electrical running-cost calculator.
Estimating purpose
An energy-cost estimate is a planning worksheet. It can compare equipment usage assumptions, operating hours and tariff inputs. It does not forecast a complete bill.
Keep the assumptions visible so another reviewer can see whether the estimate is based on measured usage, a schedule, a nameplate value or a rough allowance.
Workflow
- Identify the load or equipment being estimated.
- Confirm whether the power value is kW, W or kWh over a period.
- Record operating hours, days and duty factor.
- Enter the tariff value and note its source.
- Keep retailer, demand, network and metering exclusions visible.
Cost estimate fields
| Field | Strong record | Weak record |
|---|---|---|
| Load value | Measured, logged, scheduled or nameplate basis | Unlabelled watt value |
| Usage period | Hours, days and duty factor | One unexplained monthly number |
| Tariff | c/kWh or dollar/kWh with source | Old bill value without context |
| Exclusions | Demand charges, fixed charges and export assumptions named | Presented as total bill |
| Next action | Compare options or refine assumptions | Treat estimate as invoice prediction |
Boundaries
- Do not present the estimate as a complete electricity bill.
- Do not ignore fixed charges, demand charges, solar export, time-of-use or metering conditions when they matter.
- Do not use nameplate power when measured duty is available.
- Do not hide tariff assumptions inside the result.