Hoymiles has released the HiFlow Pro, the first plug-in solar microinverter in the US to meet the newly established UL 3700 safety standard, marking a step towards making small-scale solar power accessible to renters and apartment dwellers who cannot install rooftop panels. The device allows users to draw solar power through a standard household outlet, a technology known as "balcony solar" that a handful of US states have already legalised, with several more considering similar measures.

UL 3700, adopted in December 2025, is North America's first safety standard specifically for plug-in photovoltaic systems, addressing concerns such as the risk of electricity being fed back into the grid during power outages, which could endanger utility crews carrying out repairs. While plug-in solar units are not powerful enough to run an entire home, they offer a way to reduce reliance on the grid without requiring a full array of rooftop panels, and the new federal standard is expected to widen the potential market for solar energy beyond homeowners.