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Solar Payback Period in Washington
Estimated payback, savings, and ROI for a residential solar system in Washington — updated for 2026
Urgent tax credit deadlines
- Section 48E phase-out completes December 31, 2027 — projects must be placed in service by then (515 days left).
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Solar ROI Overview for Washington
In Washington, solar payback is driven primarily by your electricity rate ($0.149/kWh) and net-metering policy, not by sun hours alone. A typical 8kW residential system here costs about $23,040, saves $1,389 per year, and pays for itself in16.6 years. While Washington averages 3.7peak sun hours per day, the rate you pay your utility (and how your solar exports are credited) matters more for ROI than raw sunshine. See why below.
- Electricity rate: $0.149/kWh average in Washington
- System cost: about $23,040 before incentives ($2.88/W)
- Production: about 9,291 kWh/year
- Annual savings: $1,389 ($116/month)
- Payback: 16.6 years
- 25-year ROI: 51%
Savings use an NEM-adjusted effective rate (~$0.149/kWh for Washington), reflecting net metering export compensation rather than full retail.
Why your electricity rate matters more than your sun hours
Across all 50 states, electricity rate and net-metering policy explain most of the variance in solar payback, far more than peak sun hours. Hawaii and Washington make the case: Hawaii has only middling sun hours but the highest residential rates in the country, so it pays back fastest. Washington has decent Pacific Northwest sun but cheap hydro keeps rates low, so it pays back far more slowly. The rate you pay your utility, and how your exports are credited, is the dominant lever.
| State | Rate ($/kWh) | Sun hours | Payback |
|---|---|---|---|
| Hawaii | $0.520 | 6 | 3.2 yrs |
| Washington | $0.149 | 3.7 | 16.6 yrs |
| Washington (you) | $0.149 | 3.7 | 16.6 yrs |
Washington's 16.6-year payback is slower than the national average of about 10.9 years, driven by your $0.149/kWh rate and local net-metering rules, not by 3.7 peak sun hours. (Hawaii's faster payback and Washington's slower payback are the same story at the extremes.)
Payback by System Size in Washington
| System Size | Cost | Production | Annual Savings | Payback | 25yr ROI |
|---|---|---|---|---|---|
| 4 kW | $11,520 | 4,646 kWh | $695 | 16.6 yrs | 51% |
| 5 kW | $14,400 | 5,807 kWh | $868 | 16.6 yrs | 51% |
| 6 kW | $17,280 | 6,969 kWh | $1,042 | 16.6 yrs | 51% |
| 7 kW | $20,160 | 8,130 kWh | $1,215 | 16.6 yrs | 51% |
| 8 kW | $23,040 | 9,291 kWh | $1,389 | 16.6 yrs | 51% |
| 10 kW | $28,800 | 11,614 kWh | $1,736 | 16.6 yrs | 51% |
Savings use an NEM-adjusted effective rate (~$0.149/kWh for Washington), reflecting net metering export compensation rather than full retail.
How Solar Payback Works in Washington
Solar payback period is the time it takes for your cumulative electricity savings to equal the total cost of your solar system. In Washington, the calculation depends on three key factors:
- System cost — $2.88/Watt average in Washington
- Electricity rate — $0.149/kWh average utility rate
- Solar production — 3.7 average peak sun hours/day
After the payback period of 16.6 years, your solar panels continue generating free electricity for 15-20+ more years. With utility rates historically increasing 2-4% annually, your actual savings will likely exceed these estimates.
Washington Solar Data Summary
- Average Cost/Watt
- $2.88
- Average Utility Rate
- $0.149/kWh
- Peak Sun Hours
- 3.7 hrs/day
- Data Coverage
- 5 ZIP codes
Related Tools for Washington
Compare with Fastest Payback States
| State | Payback | Annual Savings | 25yr ROI |
|---|---|---|---|
| Washington (you) | 16.6 yrs | $1,389 | 51% |
| Hawaii | 3.2 yrs | $7,835 | 690% |
| California | 5.8 yrs | $4,175 | 328% |
| New York | 7.5 yrs | $3,307 | 233% |
| Massachusetts | 8 yrs | $3,112 | 214% |
| Maine | 8.3 yrs | $2,948 | 201% |
📖 Complete Guide to Solar ROI
Want to understand every factor that affects your solar payback period? Read our comprehensive guide covering financing options, NEM policies, and how to maximize your returns.
Read: Complete Guide to Solar ROI in 2026 →