Hoymiles becomes first to launch UL 3700-compliant plug-in solar microinverter in US
The HiFlow Pro device marks the first product to meet the December 2025 UL 3700 national safety standard, addressing grid safety concerns while expanding solar access to apartment dwellers.
Hoymiles has released the HiFlow Pro microinverter in the United States, positioning the device as the first product to comply with the UL 3700 national safety standard for plug-in photovoltaic systems. The launch follows the adoption of UL 3700 in December 2025, which establishes the inaugural North American safety framework for plug-in solar technology, often referred to as balcony solar. This development signals a shift toward standardising small-scale energy generation across the US market.
The HiFlow Pro allows users to generate solar power through a standard household outlet, offering a practical alternative to traditional rooftop installations. This capability is particularly relevant for renters and apartment dwellers who lack the structural rights or physical space for full-scale photovoltaic arrays. While the system is not designed to power an entire residence, it serves to reduce reliance on the existing electric grid for individual units.
A primary driver for the UL 3700 standard was the safety risk associated with power backflow during grid outages. Because plug-in converters draw electricity into a socket rather than exporting it, there was a concern that power could flow back into the grid, endangering restoration crews. The new standard mandates features to prevent accidental overloads and ensure these safety protocols are met before devices can be deployed.
Regulatory momentum for this technology is already visible at the state level. Several US states have passed laws permitting plug-in solar technology, while others have proposed measures to allow its use. The introduction of a federal standard aims to unify these efforts, providing a clear compliance pathway for manufacturers and expanding the potential consumer base for alternative energy sources.
Microinverters themselves are not a new product category, but the HiFlow Pro is notable for being the first in the US to conform to the recently enacted national safety standards. By aligning with UL 3700, Hoymiles is addressing the regulatory hurdles that have previously limited the adoption of small-scale solar setups, potentially accelerating the integration of plug-in solar into the broader energy landscape.
