The IHeat Pro-Performer AHS18-D is built for applications with more than 1 bathroom in the Southern States where the incoming water temperatures no lower than 65 degree F and can be used for 1-1/2 bathroom in the colder climates where the incoming water temperature is above 45 degree F. Because the IHeat Pro-Performer continuously monitors all real time data collected 60 times a second through a range of sensors. It automatically adjusts to any application you may have, for example floor heating, multiple units in series and recirculation configurations. The IHeat Pro-Performer boasts a 3/4 in. inlet and outlet which makes it a breeze for high flow applications. Using ASTM 304 Stainless Steel enclosure and heat exchangers ensures long lasting performance with no sediment build up or rust.