Solar Panel Payback Calculator for Washington
Washington (WA) offers moderate solar potential with an average of 3.5 peak sun hours per day. The average residential electricity rate is 11 cents per kWh, and solar installation costs average $3.00 per watt. Based on these figures, a typical 6 kW residential solar system in Washington has an estimated payback period of 18.7 years and generates $10,395 in total savings over 25 years.
Solar System Size Comparison for Washington
The table below compares four common residential solar system sizes for Washington homeowners. All calculations use the state average electricity rate of 11 cents per kWh, average installation cost of $3.00/W, and 3.5 peak sun hours. The federal 30% Investment Tax Credit is included in all scenarios.
| System Size | Gross Cost | Federal Credit | Net Cost | Annual Output | Annual Savings | Payback | 20-Year Savings | 25-Year Savings |
|---|---|---|---|---|---|---|---|---|
| 4 kW | $12,000 | $3,600 | $8,400 | 4,088 kWh | $450 | 18.7 years | $3,070 | $6,930 |
| 6 kW | $18,000 | $5,400 | $12,600 | 6,132 kWh | $675 | 18.7 years | $4,604 | $10,395 |
| 8 kW | $24,000 | $7,200 | $16,800 | 8,176 kWh | $899 | 18.7 years | $6,139 | $13,861 |
| 10 kW | $30,000 | $9,000 | $21,000 | 10,220 kWh | $1,124 | 18.7 years | $7,674 | $17,326 |
Solar Energy in Washington: What You Need to Know
Washington has some of the lowest electricity rates in the nation (hydro from Columbia River) and modest sun hours, particularly west of the Cascades. Eastern Washington has significantly better solar resources.
Electricity Rates in Washington
The average residential electricity rate in Washington is 11 cents per kWh, which is below the national average of approximately 16 cents per kWh. Lower electricity rates mean the payback period is longer, but the 25-year savings are still substantial. As electricity rates continue to rise (averaging 3% per year nationally), the value of solar ownership increases over time.
Peak Sun Hours and Solar Production
Washington averages 3.5 peak sun hours per day, which is on the lower end for the United States. However, solar panels produce electricity even on cloudy days, and the economics can still work — especially in states with high electricity rates or valuable SREC programs. A 6 kW system in Washington produces approximately 6,132 kWh per year, accounting for standard system efficiency losses and typical weather patterns.
Washington Solar Incentives and Programs
Washington's solar production incentive expired. Net metering available. Sales tax exemption on solar equipment (under $50,000). No property tax increase for solar. 100% clean electricity standard by 2045.
Incentive Summary for Washington
- Federal Tax Credit: 30% ITC (available through 2032)
- State Tax Credit: None
- Net Metering: Available
- SRECs: Not available
- Avg. Installation Cost: $3.00/watt (before incentives)
How Washington Compares to Similar States
Below is a comparison of Washington with five states that have similar solar conditions. All calculations are based on a 6 kW residential system using each state's average electricity rate and sun hours.
| State | Sun Hours | Rate (c/kWh) | Cost/Watt | Net Cost | Payback | 25-Yr Savings |
|---|---|---|---|---|---|---|
| Washington | 3.5 | 11c | $3.00 | $12,600 | 18.7 years | $10,395 |
| Michigan | 3.5 | 18c | $3.10 | $13,020 | 11.8 years | $24,609 |
| Oregon | 3.5 | 12.5c | $3.00 | $12,600 | 16.4 years | $13,531 |
| Vermont | 3.5 | 21c | $3.25 | $13,650 | 10.6 years | $30,250 |
| Connecticut | 3.8 | 27c | $3.20 | $13,440 | 7.5 years | $47,845 |
| Maine | 3.8 | 22c | $3.15 | $13,230 | 9.0 years | $36,706 |
Environmental Impact of Solar in Washington
Installing a 6 kW solar system in Washington offsets approximately 5,243 pounds of CO2 per year, which is equivalent to planting 43.3 trees annually. Over the 25-year lifespan of your solar system, that adds up to roughly 131,075 pounds of avoided carbon emissions. Choosing solar energy is one of the most impactful steps a homeowner can take to reduce their carbon footprint and contribute to cleaner air in Washington communities.
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