From Roof to Balcony: Plug-In Solar May Lower Installation and Pricing Pain Points for US Customers
An energy trend is gaining momentum in the U.S. across the commercial real estate and multi-family housing sectors. The spotlight is on “balcony solar,” exploring whether this plug-in direction offers a safe, viable path to affordable renewable energy.
In California, Gov. Gavin Newsom recently signed the Plug and Play Solar Act (Senate Bill 868). The legislation aims to help Californians invest in renewable energy, minus the large rooftop solar panels. Clearing the way toward installing “balcony solar” expands access to millions of apartment renters and lower-income homeowners looking to reduce high energy bills in lower-income circles.
“Electricity costs have reached ridiculous levels here in California, and now that the Plug and Play Solar Act is law, Californians have a much-needed tool to provide relief,” said California Sen. Scott Wiener, in a statement.
California is now the 10th state to legalize balcony solar in just two years, and its size effectively doubles the size of the balcony solar U.S. market. California joins states like Utah, which trailblazed the path forward as the first state to enact a clear framework for plug-in solar in 2025. Utah’s House Bill 340 ditched an interconnection requirement for panels with low power capacity and that are certified by a national testing facility.
Traditional rooftop solar requires high up-front costs, including professional installation, permitting and utility interconnection agreements. As a result, costs to install rooftop solar can exceed $10,000 for the average homeowner.
Plug-in solar is a compact system designed for any outdoor space that receives sunlight, which a user can essentially install on their own at a fraction of the cost (from $300 to $2,200), according to Plug-in Solar Guide. These photovoltaic systems typically range from 400 to 1,200 watts (1.2 kW) and connect directly to a standard ground-fault circuit interrupter (GFCI) outlet.
The plug and play systems are intended to offset a user's electricity consumption and ultimately lower their utility bill. The Environmental Working Group, an American nonprofit non-partisan organization, reported that a single 400-watt balcony solar system can cover about 14% of the average apartment’s electricity usage, resulting in savings of about $250 annually.
For California, electricity rates have nearly doubled over the past decade, with the nation’s second-highest energy prices behind Hawaii, according to the U.S. Energy Information Administration (EIA).
Countries like Europe have already widely adopted balcony solar to unlock residential and small commercial renewables into the plug-in solar market. German federal network agency Bundesnetzagentur reports plug-in solar system installations surpassed 700,000 as of October 2024. Today, government registry data lists over 1.5 million systems installed in Germany, with over 4 million unregistered setups reported.
However, in the U.S., regulatory barriers have limited this technology due to potential safety standards and strict utility interconnection requirements. According to UL Solutions, some of the potential negatives around plug-in solar focus on whether alternative kWs can be a safety issue.
Examples of this include a phenomenon called "breaker masking" when a solar kit feeds alternative kW into a shared wall outlet. It can result in the total current running through the household wires exceeding the rated safety threshold without tripping an electrical breaker.
Although plug-in solar is simple to use and install, this potential risk occurs when systems become overloaded and can potentially allow flow back into lines.
“There’s a way for it to work, but we want it to work safely,” Joseph Bablo, manager of principal engineering, energy and industrial automation at UL Solutions, told MIT Technology Review in an interview.
Developers are working to ensure these systems can meet UL 3700 safety standards, which help mitigate potential risks. As of May, not a single plug-in solar system on the market had achieved full certification from UL Solutions, a global leader in applied safety science.
Massachusetts and Pennsylvania are actively working toward advancing potential acceptance of plug-in solar. Lawmakers in both states are seeking measures to balance consumer affordability with grid safety, structuring regulatory frameworks that incorporate hardware certification to satisfy energy market standards.
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Eric Moody