Noritz America expands its ecoTough and ValueSolutions tankless water heater series with three models. All models feature a 12-year heat exchanger, scale-detection software and an integral readout window that displays flow rates, temperature and common error codes. The NR501 is an outdoor unit for one-bath homes in warmer climates. Also for outdoor installation, the NR662 is for homes with one-and-a-half-baths. The NRC711 stresses high efficiency and a lower carbon footprint.