Product Japan

Third Generation of ECO ONE (Hybrid Water Heater with Heating System) Released

In April 2015, Rinnai Corporation, a comprehensive manufacturer of heat and energy appliances, began selling the third generation of ECO ONE, its hybrid water heater with heating system.


ECO ONE is a residential-use hybrid water heater with heating system that uses heat from the air, extracted by an electric heat pump, and a high-capacity Eco Jozu gas water heater capable of instantly heating water. It delivers a high level of energy efficiency by utilizing the full potential of a heat pump with backup support provided by Eco Jozu when instantaneous hot water is required.


Rinnai first launched ECO ONE in 2010 as the world’s first residential water heater with heating system combining a heat pump with a high-efficiency gas water heater. In 2012, we unveiled the second-generation model featuring enhanced energy efficiency. At the same time, we expanded our lineup to include a more compact model that can be installed in multiple-dwelling buildings, as well as a double-hybrid model that not only heats water but also uses heat from the heat pump for floor heating.


In Japan, bathtub bathing is common, and water heating accounts for the highest share of energy consumption in the residential sector. The new third-generation ECO ONE hybrid water heater with heating system achieves a primary water-heating energy efficiency of 138% (based on Japanese efficiency calculation), among the highest in the world, which greatly contributes to energy savings in Japanese homes.


Going forward, the Rinnai Group will emphasize product development aimed at enriching people’s lives while promoting business in an environmentally friendly manner. These efforts will be guided by the themes of “heat and lifestyles,” “product quality,” and “contributing to local communities”—which we have embraced since our foundation.