Navien’s NPE-A series ComfortFlow technology incorporates a built-in buffer tank and recirculation pump inside the unit to provide a 0-gpm activation rate. With the ComfortFlow buffer tank, the “cold-water sandwich” is eliminated. With a return line, the pump saves thousands of gallons of water per year. Additional Navien NPE standard features include dual stainless-steel heat exchangers, 1/2” gas lines up to 24’ and 2” PVC venting up to 60’. These technical advances make the NPE-A series ideal for commercial and residential tank water-heater replacement as well as new construction.Navien water-saving unit