There’s a Far Cheaper Way to Do Rooftop Solar

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Rooftop solar, particularly in the United States, had some challenges even before Donald Trump re-entered the White House. Getting a permit to connect to the grid is expensive and time-consuming, and the entire operation has high up-front costs, increasing barriers for those without personal wealth. As my colleague Emma Janssen recently wrote in the Prospect, the American solar industry is lousy with scam artists who rope people who can’t afford to lay out the expense into predatory borrowing for wildly overpriced systems with high-pressure sales tactics.

For those who can afford solar, the typical “net metering” policy, in which you are paid for energy you put back on the grid, has the downside of everyone who does not have solar effectively subsidizing your project. It both undermines funding for grid upgrades and maintenance while adding more strain—and given the high costs, tends to subsidize the already-wealthy.

There are ways to compensate for these problems, as Australia has shown with its world-leading rooftop solar uptake. Regulate the solar industry, streamline the permitting process, provide extra subsidies for poorer households, drive costs as low as possible, upgrade the grid to take advantage of distributed generation, and so on. Alas, with Trump repealing the 30 percent federal rooftop solar credit starting in January, and opening the door to scammers and fraudsters of any kind, plus with the American permitting process in the hands of a million city bureaucracies, that is unlikely to happen anytime soon.

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But even in this benighted country, there’s a way to cut through the scammers and the red tape: a DIY, off-grid system—but without cutting your grid connection. You don’t need a permit, or to pay some rip-off contractor, or to go fully off-grid, to start saving money on electricity.

You can find various detailed explanations for how to build one of these on YouTube, but the basic idea is quite simple: Buy some solar panels and hook them up to a smart battery. The battery both stabilizes the power production for steady current and spreads the power out over time. Then plug something into it, like a window air conditioner unit. That’s it.

Voila! You’re now harvesting solar power. Better still, now you’ve got some backup power if the grid goes down—even if you can just run your fridge for a day or two while the power is out (an increasingly common experience these days, and likely to get worse), you’ve saved potentially hundreds of dollars of food.

This all sounds obvious, but the key piece of technology is the battery. As I have previously written, the battery industry has seen explosive innovation of late, and only in the last few years has this kind of system become reasonably affordable and easy for the average person. In ages past, such huge batteries would have cost a lot, plus you would have needed a bunch of expensive and complicated equipment to manage the power going in and out of the storage. Now you can get the battery for cheap with power management built in.

Battery systems can get as sophisticated as your budget allows. Companies like Anker and EcoFlow sell various modular battery systems ranging from a few hours for a window AC to a week-plus of whole-home power. You can also hook your battery up to your electric panel with a transfer switch, allowing you to swap the whole house between grid and battery power, or you can get a smart panel that will do that automatically, or a big package with panels, inverter, batteries, and wiring all bundled together.

Let me sketch out some rough price estimates. For my simplest example, let’s say we buy the EcoFlow Delta Pro battery, which has a 3.6 kilowatt-hour (kWh) capacity and costs $2,000, and five 460-watt panels from Signature Solar at $177 apiece, for a total cost of $2,885. Let’s also assume that we’ve got a spot in the backyard where they can be easily mounted for optimal sunlight, and we figure out some way to use up all the power.

How quickly such a system will pay itself off depends on your electricity price, which ranges from 11.6 cents per kilowatt-hour in Utah to 43 cents in Hawaii. But let’s put this system in Salisbury, Maryland, which is close to the national average in both price (17.9 cents) and amount of sunlight it gets. According to the National Renewable Energy Laboratory, in that location our system ought to produce about 3,100 kilowatt-hours per year, worth $554. At that rate—with all-new equipment and no subsidies, which Maryland does have—it will pay for itself in a little over five years.

Obviously, those assumptions might not hold for everyone. But the system could be made cheaper with used panels, and would be much more valuable in California, where electricity is an average of 31 cents per kWh, or up to 63 cents during peak periods in some locations. Out in the Southwest, it would also generate a lot more power due to more sunny days. Plus, battery costs keep falling, so this will get cheaper over time.

Large solar-battery systems will take a lot more expertise to install. But if you can manage it, the potential savings are amazing. According to EnergySage, a typical contracted 11 kWh solar project without batteries costs $28,000 before tax credits (which, again, are expiring at the end of this year). Signature Solar, by contrast, will sell you a kit with 12.8 kWh of panels, and a smart inverter, and a 14.3 kWh battery for $12,053. Back in Maryland, that system ought to produce 18,200 kWh per year, worth about $3,250—paying for itself in less than four years.

Ironically, Trump’s Big Beautiful Bill is going to make these systems even more attractive. By strangling so many wind and solar projects while electricity demand increases, prices are bound to go up. But tariff madness and war on America’s green industry might also make the panels and batteries more expensive. If you’ve got the space and an extra bit of cash, now might be the time to start investing in a lower power bill, and cutting your carbon emissions to boot.