What is the ROI of solar panels in Illinois?

For an unshaded Chicago-area home, we estimate about 10.7% to 13.6% a year over 25 years, with payback around 8.3 years. Shade, price and how long you stay change it.

Is solar a better investment than the stock market?

It can earn a similar or higher return with far less ups and downs, and bill savings generally aren't taxed. But the money is tied to your home and its value depends on staying or getting it back when you sell.

Should I pay down my mortgage or buy solar?

Compare your mortgage rate with solar's estimated return. With a low-rate mortgage, solar usually wins; with a rate near 7%, it's closer, and a roof with shade or a high quote can tip it toward paying down the loan.

Is Solar a Good Investment in Illinois? Returns vs. Stocks

Quick answer

For a typical unshaded Illinois home, yes. Our estimates show a Chicago-area ComEd system paying back in about 8.3 years and earning roughly 10.7% to 13.6% a year over 25 years, depending on how fast electric rates rise. That compares well with a 5% Treasury, a 7% mortgage or the stock market's long-run 10%, with the tradeoff that the money is tied to your house.

What return does home solar earn in Illinois?

Estimated solar returns for unshaded homes (cash purchase, 25 years)
Home	Cost after incentives	First-year savings	Payback	Return, rates up 3%/yr	Return, flat rates
ComEd, $150/month	$10,800	$1,296	8.3 yrs	13.6%	10.7%
ComEd, $250/month	$18,800	$2,268	8.3 yrs	13.6%	10.7%
Ameren, $150/month	$11,400	$1,272	9 yrs	12.6%	9.7%
Ameren, $250/month	$19,600	$2,210	8.9 yrs	12.7%	9.8%

The return is the annual rate (internal rate of return) that the system's bill savings earn on what you paid, after the $300/kW utility rebate and Illinois Shines. It assumes a cash purchase at $3.10 per watt, panels losing 0.5% of output a year, and no repairs. Enter your own bill in the solar savings calculator.

How do you calculate solar payback and return?

1
Find the net cost
Start with the price, then subtract the utility rebate and the Illinois Shines value your installer passes on.
2
Estimate first-year savings
Multiply the energy you'll use as it's produced by your full retail rate, and exported energy by the supply credit.
3
Simple payback
Divide net cost by first-year savings. It's easy, but it ignores everything after the payback year.
4
Annual return
Find the rate at which 25 years of savings, adjusted for rate increases and panel aging, equal the net cost today.

How does solar compare with stocks, bonds or paying down a mortgage?

Solar's estimated return next to common alternatives, autumn 2026
Option	Return	Notes
Home solar (Chicago-area ComEd estimate)	About 10.7% to 13.6% a year	Paid as lower bills; tied to the house
10-year U.S. Treasury	About 5% (topped 5% in September 2026)	Guaranteed if held to maturity; interest is taxable
Paying down a 30-year mortgage	Your mortgage rate (about 7.3% for new loans in October 2026)	Guaranteed savings; less useful if your rate is low
S&P 500 stock index	About 10% a year long-run average	Swings widely from year to year; gains are taxable

Solar's return isn't guaranteed the way a Treasury's is: it depends on your roof, how long you stay and what electricity costs. But it doesn't swing like the stock market, and bill savings aren't a payment you receive, so they generally aren't taxed the way interest or dividends are. Ask a tax professional about your situation, including any Illinois Shines payments made to you directly.

If you'd finance solar, compare the loan's true cost, including any dealer fee, with the savings. A loan at a high rate can eat most of the return. See solar loans and dealer fees.

Why have Illinois electricity prices risen so fast?

Mostly because of the grid's capacity markets, which pay power plants to be available at peak times. In the PJM market that serves ComEd, the capacity price jumped from $28.92 per megawatt-day for 2024–25 to $269.92 for 2025–26, then hit the auction's price cap for both 2026–27 and 2027–28. Without the cap, the 2027–28 price would have been $529.80.

Ameren Illinois buys capacity in a different market, MISO, where the summer 2025 price also spiked. ComEd's supply price, the Price to Compare, is 10.1¢ per kWh for October 2026–May 2027, up from a 2025 average of about 8.3¢. See the Price to Compare tracker.

Nobody can promise where prices go next, which is why the table shows a flat-rate case too. Solar locks in the cost of the power it makes, so higher prices raise its return and lower prices reduce it.

Does solar add to your home's value?

Studies say owned systems do. Berkeley Lab found buyers paid about $4 per watt more for homes with owned solar, and Zillow found homes with solar sold for 4.1% more in 2019. Both are older, national studies, not Illinois-specific, and leased systems add less because the buyer has to take over the lease. See selling a home with solar.

In Illinois, that added value isn't taxed: the solar property tax rule assesses your home as if it had no solar, as long as you file the form. See will solar raise my property taxes?

What could lower your solar return?

Moving early. You get the payback only by staying, or by getting the value back when you sell.
Shade or a poor roof. Shade cuts output, and a roof that needs replacing in a few years adds removal and reinstall costs.
Repairs. A string inverter may need replacing once in 25 years; microinverters usually carry 25-year warranties.
Rule changes. Net metering for new systems already credits exports at the supply rate only. Using more of your solar at home protects the return.
Overpaying. A high price per watt or a dealer fee is the fastest way to a weak return. Check any quote with our quote checker.

Sources

This guide is general information, not tax, legal or financial advice. Incentive programs change, so confirm current terms with your installer, your utility and a tax professional.

Is solar a good investment in Illinois?