Panasonic has unveiled a new product in Japan with a PV-based charging function that uses a heat pump and hot water storage unit to save energy by maintaining bathwater temperatures at constant levels.

From April 20, Japan’s Panasonic will start offering a new air-source heat pump that can be combined with residential rooftop solar for water heating.

The Eco Cute solution includes a heat pump and hot water storage unit that purportedly saves energy by maintaining bathwater temperatures at a constant level. It also helps homeowners to save energy at night by using heat from their bathwater. In addition, the device reduces energy and water use.

The product features a solar charging function that uses surplus electricity generated and stored from PV sources. It can use electricity to boil water during the night or day, said Panasonic.

The new product also has an “emergency boiling” function that is activated when disaster warnings or bad weather warnings are issued. This means the water continues to boil automatically, so the tank is always filled with hot water.

“Therefore, hot water can be secured in case of a power outage or water outage,” said Panasonic.

The new product was developed with Tepco Energy Partner, an electricity retailer owned by Japanese utility Tokyo Electric Power (Tepco). Panasonic said the heat pump is compatible with a new Tepco electricity rate plan for solar self-consumption.

A normal heat pump water heater boils hot water at night, but the EcoCute product heats water with electricity generated in the daytime,” said Panasonic.