A real cost breakdown for a typical 6kW system in Washington, not just a national $/watt figure.
Washington has one of the lower electricity rates in the country at approximately $0.11/kWh, and a below-average solar resource, which some systems offset by sizing larger at 3.4 peak sun hours a day. Combined with a regional installed-cost estimate of $2.90/watt, a standard 6kW residential system runs approximately $17,400 before any incentives.
| Line item | Estimated cost | Share of total |
|---|---|---|
| Equipment (panels, inverter, racking) | $9,570 | 55% |
| Labor / installation | $5,220 | 30% |
| Permitting & inspection | $2,610 | 15% |
| Total (before incentives) | $17,400 | 100% |
A 6kW system in Washington costs 3% more than the average across the 50 states we track ($16,872), and the electricity rate it offsets is 32% lower than the 0.16 USD/kWh average across those same states. That combination is what actually determines whether Washington is a faster- or slower-than-average place to go solar — a lower system cost alone doesn't help if the rate you're offsetting is also low, and vice versa. See how every state stacks up on the Electricity & Solar Rate Tracker.
At $655 in estimated annual value from 5,957 kWh of yearly production, this system pays back in roughly 27 years — a longer payback period than the national average. Washington: Net metering at retail rate, low electricity rates limit payback speed. On incentives specifically: Washington's low hydro-powered electricity rates mean solar payback is naturally longer here than in most states. The federal residential tax credit (Section 25D) expired for owned systems after December 31, 2025 — see our 2026 tax credit guide for what that means for your net price.
Same assumptions as above — $2.90/watt installed, 3.4 peak sun hours, 80% system efficiency, $0.11/kWh, no federal credit — scaled to common system sizes. Real quotes usually come in slightly cheaper per watt for larger systems, and the 25-year figure assumes flat electricity prices and 0.5% yearly panel degradation (rate increases would improve it).
| System | Installed cost | Yearly output | Yearly savings | Payback | 25-yr net savings |
|---|---|---|---|---|---|
| 4 kW | $11,600 | 3,971 kWh | $437 | 26.6 yrs | $-1,310 |
| 6 kW | $17,400 | 5,957 kWh | $655 | 26.6 yrs | $-1,965 |
| 8 kW | $23,200 | 7,942 kWh | $874 | 26.6 yrs | $-2,620 |
| 10 kW | $29,000 | 9,928 kWh | $1,092 | 26.6 yrs | $-3,275 |
| 12 kW | $34,800 | 11,914 kWh | $1,310 | 26.6 yrs | $-3,930 |
Payback barely changes with system size here, because cost and savings both scale with the number of panels — what moves it is the rate you offset and your price per watt. For a 10-year payback on a 6 kW system at Washington's $2.90/watt, you would need to be offsetting about $0.29/kWh; the average rate here is $0.11/kWh, which is below that line. Treat the table as a starting point: use the calculator below with your own usage and quotes. To see how your utility's export credit and how much solar you use at home change payback, try the <a href="/tools/solar-payback-export-credit-calculator.html?state=WA">payback calculator with export credit</a>.
A typical 6kW residential solar system in Washington costs approximately $17,400 installed in 2026, based on a regional estimate of $2.90/watt — equipment usually makes up about 55% of that, labor about 30%, with the rest in permitting.
At Washington's average rate of $0.11/kWh, a 6kW system pays back in roughly 27 years — a longer payback period than the national average. Your actual number depends on your usage and roof; check it precisely with the Solar Panel Cost Calculator.
A 6kW system in Washington costs 3% more than the 50-state average of $16,872, while the electricity rate it offsets is 32% lower than the 0.16 USD/kWh average across those states.