The NCC199CDV condensing tankless water heater from Noritz America is approved for common venting up to six units in commercial applications. The unit has a thermal efficiency rating of 98 percent and is EPA Energy Star certified. It has a maximum flow rate of 11.1 gpm. With a maximum input of 199,900 Btus per hour, the NCC199CDV features two austenite, 316L stainless steel heat exchangers that resist corrosion from condensate and chloride, maximizing durability and life span. 866-766-7489; www.noritz.com.