The short answer
If you put solar panels on your roof to charge your EV, how long until they pay for themselves? With no tax credit at all, it can be as quick as about 4 years in Hawaii, about 6 years in California, or about 12 years in Texas.
But those are best-case numbers. They only hold if your car charges at home while the sun is shining. If it doesn't, the picture can change a lot, especially in California. We'll show you both.
The best case: three very different states
Here's how long a small solar system pays back in three states, if the car uses the solar power directly. It assumes a 2024 Tesla Model Y Long Range driving 35 miles a day, a 2.4 kW system costing about $7,200, no tax credits or rebates, and the car charging at home in the daytime.
| State | Average home electricity price (EIA, July 2026) | What the car's power would cost from the grid each year | Years to pay back |
|---|---|---|---|
| Hawaii | 48.0¢ per kWh | about $1,790 | about 4 years |
| California | 33.6¢ per kWh | about $1,250 | about 6 years |
| Texas | 15.9¢ per kWh | about $590 | about 12 years |
What the numbers mean
The pattern is simple: the more you pay for electricity, the faster solar pays off. Hawaii has the most expensive power in the country, so every kWh your panels make is worth the most there. Texas power is cheap, so each kWh saves you less, and it takes longer to earn back what you spent.
How we worked it out
We kept the math simple, so you can follow it or redo it for your own home.
The car: a 2024 Tesla Model Y Long Range uses about 29 kWh per 100 miles (EPA). Driving 35 miles a day, that's about 10.2 kWh a day, or about 3,723 kWh a year.
The solar system: six 400-watt panels (2.4 kW) cover that in all three states (they get about 5.2 to 6.1 peak sun hours a day). At about $3.00 per watt installed (SolarReviews reports a national average of about $3.03), the system costs about $7,200. The 30% federal tax credit ended for systems installed after December 31, 2025, so we didn't include it.
The savings: we multiplied the car's yearly energy by each state's average home electricity price from the U.S. Energy Information Administration (EIA).
The payback: system cost divided by yearly savings. For California, that's $7,200 ÷ $1,251 = about 5.8 years.
One thing to know: we used EIA's July 2026 prices, the latest available. Monthly prices move around a little, so your own bill is always the best guide.
The catch: when you charge changes everything
Those best-case numbers assume every kWh your panels make replaces a kWh you would have bought at the average price. That only happens if your car is plugged in at home during the day.
Most people drive to work, so their car is away while the panels are working. What happens to that solar power depends on how your utility treats it. California shows how big the difference can be (same car and system as above; the export credit under California's NEM 3.0 rules is roughly 5¢ per kWh):
| How you charge in California | What each solar kWh saves you | Years to pay back |
|---|---|---|
| At home in the daytime, compared with the state average price | about 33.6¢ | about 6 years |
| At home in the daytime, but you'd otherwise charge after midnight on an EV plan | about 23¢ | about 8.5 years |
| You only charge at night and have no battery | about 5¢ (the export credit) | about 39 years |
Why the last row matters
That last row is the one to watch. Under California's NEM 3.0 rules, solar you send to the grid earns only a few cents. If you then charge your car at night from the grid, your panels aren't really paying for your driving. They're selling cheap power to the utility. In that case, the payback for the EV part of the system stretches to decades.
There are two ways to fix that: charge at home in the daytime when you can (weekends count), or add a home battery to store your solar for the evening. Our home battery guide runs those numbers.
Other states have their own rules. Hawaii closed its older export programs to new customers, and Texas has no statewide net metering, so what you get for exported solar depends on your electricity provider's buyback plan. Before you trust any payback number, find out what your utility pays for solar you send to the grid.
Work out your own payback
Find the price per kWh on your electric bill, then look it up below. These numbers use the same car, system and daytime charging as our best case, in a sunny location (about 5 peak sun hours a day or more). In a cloudier area with about 4 peak sun hours, you'd need about a third more panels, so add about a third to the years.
| Your electricity price | Years to pay back |
|---|---|
| 15¢ per kWh | about 13 years |
| 18¢ per kWh | about 11 years |
| 20¢ per kWh | about 10 years |
| 25¢ per kWh | about 8 years |
| 30¢ per kWh | about 6.5 years |
| 35¢ per kWh | about 5.5 years |
| 45¢ per kWh | about 4 years |
What makes payback faster
Rebates: some states and utilities still offer solar rebates. Subtract any rebate from the system cost. For example, a $1,000 rebate cuts California's best case from about 5.8 years to about 5 years. Search the DSIRE database (dsireusa.org) to see what's offered where you live.
Counting the gas you no longer buy: we only compared solar with grid electricity. If your EV replaced a gas car, your total savings are much bigger, and the whole switch pays off far sooner.
Rising electricity prices: if your utility raises its rates, every kWh your panels make becomes worth more, and payback gets shorter. We assumed prices stay the same.
An example: Marcus in Los Angeles
Marcus bought a 2024 Rivian R1S to take his kids to soccer practice. It's a big SUV, rated at 48 kWh per 100 miles, and he drives about 35 miles a day. That's about 16.8 kWh a day, or about 6,100 kWh a year.
An installer quoted him a 4 kW system (ten panels) for about $12,000, with no tax credit. At California's average price of 33.6¢, that much electricity is worth about $2,060 a year. "It'll pay for itself in about six years," the installer said.
But Marcus works 9 to 5. On weekdays, his car is at the office while his panels are making power, so that solar goes to the grid for about 5¢ per kWh. He can only charge from the sun on weekends. When he ran the numbers that way, his solar was worth about $810 a year for the car, and the payback stretched to about 15 years.
The installer's number wasn't wrong. It just assumed Marcus would be home every day. Before signing, Marcus started looking at two options: a home battery to store his weekday solar, and an EV rate plan so his weekday charging happens at the cheapest overnight price.
Marcus is an example, not a real customer.