The first UL 3700-compliant plug-in solar microinverter is now available in the United States, marking a significant milestone for renters and apartment dwellers looking to reduce their electricity bills without installing a full rooftop solar array.
Hoymiles, a global leader in microinverter technology, recently announced the release of its HiFlow Pro microinverter, the first device of its kind to meet the newly adopted UL 3700 safety standard for plug-in photovoltaic energy systems. According to Engadget, the device plugs directly into a standard household outlet, making solar power accessible to a much wider audience.
What Is UL 3700?
Adopted in December 2025, UL 3700 is the first North American safety standard specifically designed for plug-in solar energy systems — often referred to as “balcony solar.” These compact setups allow users to connect solar panels to their home’s electrical system simply by plugging into a wall outlet, without the need for professional installation or rewiring.
The standard addresses a critical safety concern: because plug-in solar microinverters push electricity into a socket rather than drawing power from it, there is a risk that during a grid outage, electricity could backfeed into the power lines, endangering utility crews working to restore service. UL 3700 mandates features that prevent accidental overloads and ensure the system disconnects safely from the grid during outages.
“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,” the Engadget report notes.
Plug-In Solar: A Game Changer for Renters
Traditional rooftop solar installations require significant investment, structural modifications, and often homeowner approval — barriers that make solar power inaccessible to the roughly one-third of US households that rent. Plug-in solar systems like the HiFlow Pro change this equation entirely.
“Plug-in solar isn’t really capable of powering a whole apartment,” the article explains, “but it is a way of reducing reliance on the existing electric grid without needing a whole fleet of photovoltaic panels.”
A handful of states have already passed laws permitting plug-in solar technology, and several others have proposed similar measures. The availability of a UL-certified microinverter could accelerate adoption by giving consumers and regulators confidence in the safety and reliability of these systems.
What This Means for the Future
The arrival of the HiFlow Pro represents more than just a product launch — it signals that the solar industry is beginning to address the needs of a demographic that has long been overlooked: renters and apartment dwellers who couldn’t pursue full rooftop installations.
With a federal safety standard now in place and the first compliant product on the market, balcony solar could become a common sight in American cities. For millions of households without access to rooftop solar, plug-in solar offers a tangible way to participate in the clean energy transition — one outlet at a time.
The Hoymiles HiFlow Pro is available now from the company’s US distributors, with pricing varying by retailer.