All states · Illinois
Updated October 2026 · ranks 3 of 50
Yes, and faster than in almost any other state
6 kW system · $7,420 after incentives · $1,213 returned in year one
0 yrs25 yrs
A break-even point of 6.5 years is short enough that the decision turns mainly on how long the owner intends to remain in the property. The system is then owned outright for roughly 19 further years of its warranted life.
Yes. At 6.5 years, a purchased system in Illinois repays its cost faster than in almost any other state. The high retail electricity rate accounts for most of that advantage.
The case modeled here approximates an average Illinois household on the state average rate of 19.2¢, with an unshaded roof and no financing: $7,420 of capital, $1,213 returned in the first year, and break-even near year 6.5. Above-average consumption, a south-facing roof or a competitive installed price shorten that period; shading, a loan carrying a dealer fee, or a sale within six years lengthen it. Because exports earn only 8.5¢, daytime occupancy carries measurable value: a household absent between nine and five performs appreciably worse than this figure.
At 19.2¢ per kilowatt-hour, Illinois pays 16% more for electricity than the United States average of 16.5¢. A high retail rate is the principal driver of a short payback, since each kilowatt-hour generated displaces an expensive one.
A 6 kW array in Illinois generates approximately 7,851 kWh a year, above the national median. Irradiance is the one input that no change in policy can remove.
Illinois provides little or no net metering. Exported power earns approximately 8.5¢ against a retail rate of 19.2¢, roughly a quarter of its purchase price. The practical consequence is that a smaller system, consumed almost entirely on site, repays faster than a large one - the reverse of the position in full-net-metering states.
State support reduces the installed price of $18,360 by $10,940, to $7,420 before financing. This comprises $10,940 of state rebate and tax credit.
A 6 kW system, the size typical of Illinois households, costs approximately $18,360 installed at $3.06 a watt before deductions. State support reduces this by $10,940, to $7,420. That is well above the $2.85 national median, which is why a high retail rate alone does not shorten the payback here as much as it first appears. Smaller systems cost more per watt and larger ones less, although a larger array is worth less here, since exports earn only 8.5¢.
| System size | 6 kW |
|---|---|
| Annual production | 7,851 kWh |
| Installed cost | $18,360 |
| Incentives | -$10,940 |
| Net cost | $7,420 |
| Electricity rate | 19.2¢ / kWh |
| Export credit | 8.5¢ / kWh |
| Year-one saving | $1,213 |
| Break-even | 6.5 years |
| 25-year gain | $28,390 |
Of the 50 states published here, Illinois ranks third for how quickly a bought system repays itself. Fastest right now: Hawaii, New York, Massachusetts, Maine. Slowest: South Dakota, Louisiana, North Dakota, Tennessee. Compare them all on the map.
Solar economics change at state lines rather than at county lines, because the export tariff and the netting period do. These states share a border with Illinois, and the figure each produces on the same assumptions.
About $18,360 installed for a 6 kW system at $3.06 a watt. State support reduces this by $10,940, to $7,420. A system sized to daytime consumption costs less and repays faster here, because exports earn only 8.5¢.
Yes, and faster than in almost any other state. A 6 kW system breaks even in 6.5 years on the assumptions used here, following the expiry of the 30% federal tax credit on 31 December 2025.
Approximately $1,213 in the first year on a 7,851 kWh system, rising thereafter as Illinois electricity rates increase. Almost all of that derives from power consumed as it is generated; at 8.5¢, export earns little.
A 6 kW array is about 14 modules at 430 W and generates 7,851 kWh a year here, which covers a household using roughly that much. Sizing beyond on-site use is poor value in Illinois, since the surplus earns 8.5¢ against a 19.2¢ retail rate. The sizing calculator works it out from a bill.
Yes, and faster than in almost any other state. The retail rate here is 19.2¢ against a national average of 16.5¢, exports earn 8.5¢, and a 6 kW system breaks even in 6.5 years. What separates Illinois from states with similar sunshine is the rate and the export tariff, not the weather.
Illinois provides little or no net metering.
Generation is taken from NREL PVWatts v8 for the largest metropolitan area in Illinois, south-facing at 20°. The retail rate is from the EIA and the export credit from the state's net metering rule. The break-even figure incorporates 0.5% annual panel degradation, 3% annual electricity price growth, $150 a year in maintenance and an inverter replacement in year 12. The federal credit is set to $0 — Section 25D expired 31 December 2025. Imports and exports are netted over short intervals, so only about 65% of generation offsets consumption at the full retail rate. Full method and sources. Privacy. Export terms checked against the state source in September 2026.
These are estimates for comparison between states, not quotations. Roof orientation, shading, consumption pattern and installer pricing all affect the result. At least three written quotations are advisable before purchase.