California-based sodium-ion battery developer Unigrid has launched Na+Casa, its first residential energy storage system, and said it has completed initial installations in homes across Europe.

The Na+Casa system uses battery cells featuring the company’s proprietary sodium chromium oxide (NaCrO₂, or NCO) cathode technology. Unigrid claims the chemistry enables a long operational lifespan and eliminates the fire risk associated with conventional lithium-ion batteries.

According to the company, the Na+Casa battery is rated for 10,000 full charge-discharge cycles at 100% depth of discharge, equivalent to daily cycling for more than 27 years. Some of Unigrid’s commercial battery products are rated for more than 30,000 cycles.

The company also highlights the system’s broad operating temperature range. The battery can reportedly charge at temperatures from -20 C to 60 C and discharge between -40 C and 60 C.

“As residential energy bills rise — especially during extreme weather events such as the record heatwave we are seeing around the world — homeowners need storage that is safe, reliable, and financially sound,” Unigrid CEO Darren H. S. Tan said in a statement. “With Na+Casa, Unigrid is moving NCO sodium-ion from just a promising technology to a tangible residential storage product, giving installers and integrators an alternative to lithium-ion.”

The Na+Casa battery module is designed for wall mounting or installation with optional wheels. The unit weighs 108.9 kg and measures 477 mm x 869 mm x 269 mm.

Each battery provides 9.25 kWh of usable energy, with a nominal voltage of 46.4 V and a standard charge and discharge current of 50 A. The system can support discharge pulses of up to 200 A, according to the company.

The batteries currently hold UN 38.3 certification for transport. Unigrid said it expects to complete CE marking and UL 9540 and UL 1973 certifications in the near future.

The company said the Na+Casa system is compatible with most existing hybrid inverters and was designed to simplify residential solar retrofits while remaining cost-competitive with lithium-ion storage products. Unigrid expects to launch the battery in the United States by the end of 2026.

The Na+Casa system joins a growing number of sodium-ion residential storage products entering global markets. Other companies developing sodium-ion home energy storage solutions include Eleven Energy, Biwatt, and Lithium Valley, with the latter two having obtained UL certifications required for sales in the US market.

Unigrid has previously said it aims to reach 1 GWh of annual battery cell production capacity in 2026. Tan has also promoted the technology’s long lifespan as a potential fit for third-party ownership and leasing models.

The company plans to test that approach in commercial energy storage projects in California later this year, with the residential product complementing its larger commercial battery systems.

“It’s going to be a long-term asset, and by offering it at zero money down, we can reap monthly benefits together with the user rather than forcing them to fork out a large amount of cash on day one hoping that this thing will last 25 years,” Tan told pv magazine USA in May 2026. “We take the risk away from them.”