Hoymiles Releases HiFlow Pro Microinverter, First in US to Meet New Plug-in Solar Safety Standard UL 3700

Last week, Hoymiles released its HiFlow Pro microinverter, which allows for use of solar power drawn through a typical household outlet. A few states have passed laws permitting this plug-in solar technology, and several others have proposed measures to allow it. As Electrek reports, while microinverters are not a new product category, this one from Hoymiles is notable for being the first in the US to conform to the recently enacted national safety standards. Adopted in December 2025, UL 3700 is the inaugural North American safety standard for plug-in photovoltaic energy systems, sometimes referred to as "balcony solar."

One of the major issues toward adopting these small-scale solar panels is the risk that, since the converters draw electricity into a socket rather than out of it, power would be drawn into the grid during outages. This would endanger any crews working to restore service, so UL 3700 standardizes the features for preventing any accidental overloads among other safety concerns.

Plug-in solar isn't really capable of powering a whole apartment, but it is a way of reducing reliance on the existing electric grid without needing a whole fleet of photovoltaic panels. Having a federal standard for these smaller setups expands the potential consumer base for solar to renters and apartment dwellers who couldn't pursue full rooftop installations.