The NCC199CDV condensing tankless water heater from Noritz is approved for common-venting up to six units in commercial applications. The Wi-Fi-enabled unit has a thermal efficiency rating of 98 percent, which is the industry's highest, making it EPA ENERGY STAR certified. It has a maximum flow rate of 11.1 gallons per minute. With a maximum input of 199,900 BTUs per hour, the heater features two austenite 316L stainless steel heat exchangers. BTU input can range from 18,000 to 4.8 million (for a 24-unit multi-system), yielding up to a 266:1 turndown ratio.