Part 6/9:
However, whilst this design optimizes performance, it does come with limitations. There's a ceiling to how much hot water can be produced at any given time. Using a lower flow rate — for example, a 1.5-gallons-per-minute showerhead — means that the heater must continually catch up, resulting ultimately in a depletion of hot water after extensive use.
Yet, this engineered sequence allows for faster recovery times. When evolving hot water demands exhaust the supply, the strategic activation of the upper element can provide hotter water again swiftly, generally within 45 minutes. In contrast, having both elements working simultaneously would extend recovery times significantly.