The Marey ECO150 14. 6Kw unit is ideal for up to two simultaneous points of use increasing incoming water temperature up to 41°f at a 2. 5Gpm water flow rate. The Marey eco series tankless water heaters are the only ones in the market to include a German-designed, patented heating element with a stainless steel water channel. This high quality component is corrosion resistant and reduces hard water build up from chlorine and calcium.