All states · Washington
Updated October 2026 · ranks 43 of 50
Not on the arithmetic alone
6 kW system · $17,160 after incentives · $960 returned in year one
0 yrs25 yrs
At 18.1 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 18.1 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 Washington household on the state average rate of 14.7¢, with an unshaded roof and no financing: $17,160 of capital, $960 returned in the first year, and break-even near year 18.1. 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. Exports earn 14.7¢, close to the retail rate, so daytime occupancy makes little difference to the result.
At 14.7¢ per kilowatt-hour, electricity in Washington costs 11% 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 Washington generates approximately 6,527 kWh a year, below the national median. This is not disqualifying - Germany installs solar at lower irradiance than any US state - but it means the retail electricity rate matters more here than the weather does.
Washington operates full-retail net metering. Each exported kilowatt-hour is credited at the same 14.7¢ charged for consumption, so the grid functions as storage and there is no penalty for generating more than is consumed during daylight hours. This is the principal reason payback here is shorter than in states with comparable irradiance.
Washington offers no state rebate or tax credit at present, so the installed price of $17,160 stands. With Section 25D expired there is no federal credit to deduct either, the first year in over a decade in which that has been the case.
A 6 kW system, the size typical of Washington households, costs approximately $17,160 installed at $2.86 a watt before deductions. No deduction applies in Washington: there is no state rebate, no state tax credit, and no federal credit following the expiry of Section 25D on 31 December 2025. 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 sizing beyond on-site consumption is not penalized, since exports earn 14.7¢.
| System size | 6 kW |
|---|---|
| Annual production | 6,527 kWh |
| Installed cost | $17,160 |
| Incentives | none |
| Net cost | $17,160 |
| Electricity rate | 14.7¢ / kWh |
| Export credit | 14.7¢ / kWh |
| Year-one saving | $960 |
| Break-even | 18.1 years |
| 25-year gain | $10,022 |
Of the 50 states published here, Washington ranks 43rd 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 Washington, and the figure each produces on the same assumptions.
About $17,160 installed for a 6 kW system at $2.86 a watt. No deduction applies in Washington: no state rebate, no state credit, and no federal credit following the expiry of Section 25D. Larger systems are not penalized here, since exports earn the full 14.7¢.
Not on the arithmetic alone. A 6 kW system breaks even in 18.1 years on the assumptions used here, following the expiry of the 30% federal tax credit on 31 December 2025.
Approximately $960 in the first year on a 6,527 kWh system, rising thereafter as Washington electricity rates increase. Exports are valued the same as self-consumption at 14.7¢, so the figure holds regardless of daytime occupancy.
A 6 kW array is about 14 modules at 430 W and generates 6,527 kWh a year here, which covers a household using roughly that much. Sizing above on-site use is not penalized here, since exports earn 14.7¢. The sizing calculator works it out from a bill.
Not on the arithmetic alone. The retail rate here is 14.7¢ against a national average of 16.5¢, exports earn 14.7¢, and a 6 kW system breaks even in 18.1 years. What separates Washington from states with similar sunshine is the rate and the export tariff, not the weather.
Washington operates full-retail net metering.
Generation is taken from NREL PVWatts v8 for the largest metropolitan area in Washington, 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. Credits accumulate across the year, so close to 95% of generation is valued 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.