Typical heat pumps use storage tanks and deliberately keep the domestic water stratified at various temperatures. Stratification is needed to enable the heat pumps to operate efficiently. Stagnation and water temperature being in the growth range of Legionella pose a substantial risk. The Electron series does not store any water, heats on-demand, and has water velocities that are 400 times higher than a tank, thus mitigating biofilm formation and reproduction of Legionella bacteria. This results in good, safe, clean, and efficient hot water.