Washington State has the cheapest residential electricity in the continental US at roughly $0.11/kWh, thanks to abundant hydroelectric generation. That makes solar payback slow — typically 12-15 years. Washington has a 100% solar sales tax exemption and net metering with annual true-up at retail rate, but no state income tax credit.
Use the calculator below — your state is already selected. Adjust your monthly electric bill and system cost for a Washington-specific payback estimate.
Solar Payback Calculator (by State)
Estimate your system size, total cost after incentives, and break-even year for residential solar.
Estimated payback period
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Select your state to get a precise estimate.
System size
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25-year savings
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Net cost after credits
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Year-1 savings
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Cost breakdown
| Net out-of-pocket | $0 |
Estimates only. Real solar quotes depend on your roof, shading, local installer pricing, utility net-metering policy, and your specific tax situation for the federal credit. Not financial advice.
Cumulative savings vs. system cost
When the green line crosses the dashed cost line, you’ve broken even.
Washington solar specifics
1. Federal 30% ITC
Standard.
2. Sales tax exemption
100% sales tax exemption on solar PV equipment in Washington. Saves $1,500-$2,500 on a typical residential system (WA sales tax is 6.5% + local up to ~10% combined).
3. Full retail net metering
WA utilities (Puget Sound Energy, Seattle City Light, others) net meter at retail rate. Annual true-up: any excess credits at year-end are typically forfeited to the utility.
4. Low electricity rate
Hydro-powered electricity costs $0.10-$0.13/kWh — among the cheapest in the US. This is the structural issue for solar payback in WA.
5. Low sun hours
WA's 3.8 peak sun hours/day is one of the lowest in the continental US.
What 2026 Washington solar economics look like
Typical 7 kW WA system:
- Gross system cost: $19,600 ($2.80/W)
- Federal 30% ITC: -$5,880
- Net cost: $13,720
- Annual production: ~8,400 kWh (WA sun is below average)
- Annual savings at $0.11/kWh, full retail NEM: ~$924
- Simple payback: ~14.8 years
Solar in WA makes sense for environmental reasons but doesn't pay back economically in the way it does in higher-electricity-rate states.
How to use the Washington solar calculator above
- The state is pre-selected. Adjust if needed.
- Enter your typical monthly electric bill (averaged across the year).
- The calculator auto-fills your state's average electricity rate and peak sun hours — override the electricity rate with your real $/kWh from your bill if you know it.
- Adjust the system cost per watt based on quotes from local installers. Washington averages are typically within the $2.50–$3.50/W range for cash installs.
- The output shows estimated system size, net cost after federal and state credits, year-1 savings, and 25-year cumulative savings.
Related
- Main Solar Payback Calculator (all 50 states)
- Solar Tax Credit 2026 — full explainer
- Heat Pump vs Gas Furnace Calculator
- All CalcCottage calculators
Reviewed by the CalcCottage editorial team. Updated May 14, 2026. Estimates only — not financial advice. Verify current incentives at DSIRE.org before installing.
Solar payback in other states
- Alabama
- Alaska
- Arizona
- Arkansas
- California
- Colorado
- Connecticut
- Delaware
- District of Columbia
- Florida
- Georgia
- Hawaii
- Idaho
- Illinois
- Indiana
- Iowa
- Kansas
- Kentucky
- Louisiana
- Maine
- Maryland
- Massachusetts
- Michigan
- Minnesota
- Mississippi
- Missouri
- Montana
- Nebraska
- Nevada
- New Hampshire
- New Jersey
- New Mexico
- New York
- North Carolina
- North Dakota
- Ohio
- Oklahoma
- Oregon
- Pennsylvania
- Rhode Island
- South Carolina
- South Dakota
- Tennessee
- Texas
- Utah
- Vermont
- Virginia
- West Virginia
- Wisconsin
- Wyoming