tl;dr: Hitachi is launching its Y-series EcoCute CO2 heat pump water heaters in Japan starting November 2026, in 370L and 460L configurations with a five-year warranty. The main upgrade is expanded support for daytime electricity tariffs aimed at households with solar PV, selectable via the remote controller, rather than changes to the underlying heat pump hardware or HEMS connectivity, which was already present in prior models.