Electric water-heater cost calculator
Estimate the cost of an electric storage water heater, immersion heater, instant heater, or geyser using power, heating time, and tariff.
Transparent method
The calculation
Water-heating cost = element kW × active heating hours × tariffThis planning model treats heating-element runtime as the key variable. Storage losses, inlet-water temperature, tank size, and thermostat settings determine how long the element actually runs.
Read the full methodology →Sensitivity check
Run three scenarios.
01
One-person useModel a shorter daily heating window.
02
Typical householdStart with your timer or observed element runtime.
03
High demandIncrease heating cycles for a larger household.
Use the result well
What can change the answer?
- Do not treat time powered on as time the element is active.
- Storage tanks lose heat between uses.
- Instant heaters draw high power for shorter periods.