Utah was the first state to legalize balcony solar in the spring of 2025, and nine states subsequently passed similar legislation— Colorado, Connecticut, Maine, Maryland, New Hampshire, New Jersey, Vermont, Virginia, and now, California. New York lawmakers approved a bill that is awaiting the governor’s signature, while nearly two dozen other state legislators have introduced them.

Plug-in solar systems, typically comprised of one to three panels to stay below the maximum wattages allowed by the laws, enable users to save money on their power bills and to reduce the energy they use from power plants that generate electricity by burning fossil fuels. “The appeal of being able to make your own electricity, and for less money than you can buy it from a utility, that’s universal for Americans,” says Joshua Pearce, an electrical engineer at Western University in Ontario, Canada, who advanced the merits of plug-in solar a decade ago.

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For most homes, electricity is generated in faraway power plants and transmitted through power lines. Homes where rooftop solar creates electricity wire the energy into the home through the circuit breaker panel, and excess electricity flows back to the utility. But power from plug-in systems stays in the home. With a small metal box called an inverter attached to the panels and plugged into the outlet, electrical currents are pushed to other outlets throughout the residence. Systems typically contribute 10 to 30 percent of an average home’s use, says Jennifer Eden, who works on renewable energy programs for the policy nonprofit Utah Clean Energy.

The set-ups have become especially popular in Europe. Swedish furniture chain IKEA sells plug-in solar kits in Germany, a country where more than a million units have been installed in the past few years.