All states · Idaho
Updated October 2026 · ranks 45 of 50
Not on the arithmetic alone
6 kW system · $16,640 after incentives · $897 returned in year one
0 yrs25 yrs
At 18.9 years the payback extends past the point at which the inverter, and possibly the roof, require replacement, and capital invested elsewhere would generally return more. This does not make solar unsuitable here for backup power or emissions reduction; it makes it a different kind of decision from an investment.
Not on the arithmetic alone. At 18.9 years the payback runs beyond the service life of the inverter, and capital placed elsewhere would usually return more.
The case modeled here approximates an average Idaho household on the state average rate of 13.7¢, with an unshaded roof and no financing: $16,640 of capital, $897 returned in the first year, and break-even near year 18.9. 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 3.8¢, daytime occupancy carries measurable value: a household absent between nine and five performs appreciably worse than this figure.
At 13.7¢ per kilowatt-hour, electricity in Idaho costs 17% less than the United States average of 16.5¢. Inexpensive grid power lowers household bills but weakens solar economics, since each kilowatt-hour generated displaces a cheap one.
A 6 kW array in Idaho generates approximately 8,737 kWh a year, above the national median. Irradiance is the one input that no change in policy can remove.
Idaho provides little or no net metering. Exported power earns approximately 3.8¢ against a retail rate of 13.7¢, 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 $17,460 by $820, to $16,640 before financing. This comprises $820 of state rebate and tax credit.
A 6 kW system, the size typical of Idaho households, costs approximately $17,460 installed at $2.91 a watt before deductions. State support reduces this by $820, to $16,640. Prices vary with roof complexity, equipment selection and local installer demand; quotes $0.40 a watt either side of this figure are common. Smaller systems cost more per watt and larger ones less, although a larger array is worth less here, since exports earn only 3.8¢.
| System size | 6 kW |
|---|---|
| Annual production | 8,737 kWh |
| Installed cost | $17,460 |
| Incentives | -$820 |
| Net cost | $16,640 |
| Electricity rate | 13.7¢ / kWh |
| Export credit | 3.8¢ / kWh |
| Year-one saving | $897 |
| Break-even | 18.9 years |
| 25-year gain | $8,400 |
Of the 50 states published here, Idaho ranks 45th for how quickly a bought system repays itself. Fastest right now: Hawaii, New York, Illinois, Massachusetts. 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 Idaho, and the figure each produces on the same assumptions.
About $17,460 installed for a 6 kW system at $2.91 a watt. State support reduces this by $820, to $16,640. A system sized to daytime consumption costs less and repays faster here, because exports earn only 3.8¢.
Not on the arithmetic alone. A 6 kW system breaks even in 18.9 years on the assumptions used here, following the expiry of the 30% federal tax credit on 31 December 2025.
Approximately $897 in the first year on a 8,737 kWh system, rising thereafter as Idaho electricity rates increase. Almost all of that derives from power consumed as it is generated; at 3.8¢, export earns little.
A 6 kW array is about 14 modules at 430 W and generates 8,737 kWh a year here, which covers a household using roughly that much. Sizing beyond on-site use is poor value in Idaho, since the surplus earns 3.8¢ against a 13.7¢ retail rate. The sizing calculator works it out from a bill.
Not on the arithmetic alone. The retail rate here is 13.7¢ against a national average of 16.5¢, exports earn 3.8¢, and a 6 kW system breaks even in 18.9 years. What separates Idaho from states with similar sunshine is the rate and the export tariff, not the weather.
Idaho provides little or no net metering.
Generation is taken from NREL PVWatts v8 for the largest metropolitan area in Idaho, 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 August 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.