Hitachi Global Life Solutions, a unit of Japanese technology conglomerate Hitachi, has announced a new series of residential EcoCute heat pump water heaters for the Japanese market, with sales set to begin progressively in November 2026.

The new Y series uses natural refrigerant carbon dioxide (CO2) and is available in several configurations. At the top of the range are the BHP-FV37YD and BHP-FV46YD, two fully automatic models featuring direct mains-pressure hot-water delivery. They have storage capacities of 370 liters and 460 liters, respectively.

The 370-liter model is designed for households of around three to five people, while the 460-liter unit is aimed at households of four to six people.

Hitachi has not yet disclosed full efficiency specifications for the two new models. Their predecessors, the BHP-FV37WD and BHP-FV46WD, have annual hot-water and heat-retention efficiency ratings under Japanese Industrial Standards (JIS) of 4.2 and 4.1, respectively. The 370-liter predecessor uses a BHP-HAV45W heat pump unit, while the 460-liter version uses a BHP-HAV60W unit.

The manufacturer has not indicated whether the Y-series models feature a new compressor, refrigerant circuit or heat-exchanger architecture. Based on the specifications disclosed to date, the products appear to be an upgrade of Hitachi’s existing EcoCute platform rather than a new heat pump design.

One of the main changes in the Y series is expanded compatibility with Japanese electricity tariffs that encourage consumers to shift electricity consumption to daytime hours.

Some Japanese utilities have introduced tariffs designed to encourage daytime water heating as growing volumes of solar generation enter the grid. Hitachi said Y-series owners will be able to select supported electricity contracts through the water heater’s remote controller, while other tariffs can be configured manually.

The company said the new tariff-setting functionality is intended for electricity plans that encourage daytime consumption, including tariffs designed for households with PV systems.

The Y series also supports Hitachi’s home energy management system (HEMS) through a HEMS connection adapter and wireless LAN adapter.

HEMS connectivity is not new to Hitachi’s high-efficiency EcoCute products. The preceding BHP-FV37WD and BHP-FV46WD models already supported connected energy-management functions, including Echonet Lite compatibility and solar-powered water-heating operation. The main energy-management change in the Y series therefore appears to be expanded support for utility tariff structures rather than the introduction of HEMS connectivity itself.

Hitachi is also introducing a five-year manufacturer warranty for the Y series. The warranty covers the heat pump unit, hot-water storage unit, specified consumable components, remote controller, wireless LAN adapter and HEMS adapter.