An ENERGY STAR® qualified model designed to give consumers comfort and safety as well as energy and cost efficiency. Indeed, this model also complies with quality and safety standards for Low NOx emission with (≤ 20ppm) emission. The added built-in security features of this model prevent unauthorized changing of the preferred pre-set temperature. In addition, this model is equipped with built-in Rinnai Circ-Logic™ external pump with recirculation program cycle, which functions at pre-set temperature and interval for consumer comfort and maximum efficiency. Also, this model has multiple venting options to allow easy installation. Moreover, this indoor tankless water heater is provided with a limited warranty for parts and labor and a separate warranty for the heat exchanger material.