Will this storage water heater cover the planned showers?
Tank litres are not shower litres. First calculate the hot-water fraction at the entered temperatures, add conservative heat recovery, simulate the exact shower sequence and compare the separate manufacturer FHR input.
Method
Mixing uses a temperature balance. Recovery uses water heat capacity, entered kW and an editable efficiency assumption. FHR remains a label value and is never inferred from tank size.
Important limitation
Stratification, thermostat cycling, pipe loss, simultaneous taps, local anti-scald rules and installation supply can change actual performance. A qualified installer must verify them.