Everyone is suddenly talking about rooftop solar, and the reason is a federal data release showing that small systems now make nearly five times the electricity they did ten years ago. If you are weighing panels for your own roof, the slowdown matters, because growth has leaned on state rules about what utilities pay for power sent back to the grid, and those rules are changing. One limit up front: the report summary doesn't say what share of all US electricity this represents, so we won't put a figure on it. Here is the whole story in about three minutes.
What counts as rooftop solar?
The U.S. Energy Information Administration (EIA) tracks "small-scale" solar, meaning systems under 1 megawatt, which covers rooftops on homes and many businesses. Most of these systems don't report their output directly. The agency estimates it from utility survey data on customers and capacity, run through modeling tools from the National Renewable Energy Laboratory. So these are modeled figures, not meter readings.
How big has it gotten?
Small-scale solar produced roughly 93,000 gigawatt-hours in 2025, up from under 19,000 a decade earlier. The pv magazine USA write-up of the EIA report calls that a quadrupling. By our arithmetic it is closer to five times, so "quadrupled" is, if anything, modest.
Who leads, and who surprised?
California, by a distance. It makes about 37% of the national total, and its output grew 8% last year as operating capacity climbed from 18 to 20 gigawatts. Arizona comes second, helped by a state income tax credit and local utility incentives.
Texas and Florida have grown from almost nothing a decade ago, aided by property tax exemptions and state programs. New York ranks fifth despite far less sunshine than the Southwest, which says something about what good incentives and better technology can do. New Jersey, Massachusetts and Illinois have seen similar programs push growth.
Why has growth cooled?
2022 was the peak, with output up 25% on record installations. Part of that was a rush before California moved to its Net Billing Tariff, known as NEM 3.0, in April 2023, which lowered what homeowners are paid for power they send back to the grid. Grandfathering under the old rules pulled installations forward, so the boom was partly borrowed from later years. Arizona shows the same shape: growth there slowed to 6% in 2025. The EIA says national growth rates have moderated since 2022.
What is still unknown?
We can't tell how much of the slowdown comes from changing rules and how much from weaker demand. And a caveat on our own reading: we worked from a trade-press write-up of the EIA report, not the report itself, so the underlying tables are worth checking.
What happens next?
Watch whether the slowdown steadies or deepens, and whether home batteries and virtual power plants change the math in places where export payments have shrunk. If your utility pays little for the power you send back, is a rooftop system still worth it?
The WattsUpNext take: US rooftop solar has grown several times over in a decade, but the pace is slowing and California still dominates. Its next chapter depends more on state rules than on sunshine.
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Sources
Reported by the WattsUpNext desk from the sources linked below. Spot an error? Tell us at corrections@wattsupnext.com.
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