Last Updated: May 19, 2026 | Reviewed by: Dylan DeSantis, SolarMetric
Quick Answer
Solar panels cost an average of $2.78 per watt installed in Washington State — $27,800 for a typical 10 kW system. Washington has some of the cheapest electricity in the country (averaging $0.113/kWh), which significantly extends solar payback periods — typically 14–18 years in the Seattle area. For homeowners in eastern Washington (Spokane, Tri-Cities, Yakima) with more sun hours, payback runs closer to 11–13 years. Washington has no income tax, no state sales tax on solar equipment, and offers net metering through 2029 under state law.
⚠️ Federal Tax Credit Update (Important for 2026)
The 30% federal residential solar tax credit (Section 25D) was terminated by the One Big Beautiful Bill Act, signed into law on July 4, 2025. It no longer applies to solar systems installed on or after January 1, 2026. Homeowners who completed their Washington installation in 2025 can still claim the credit on their 2025 tax returns via IRS Form 5695.
For 2026 installations:
– Homeowner-purchased systems: No federal income tax credit available.
– Solar leases and PPAs: Installers retain the commercial ITC (Section 48E). Lease rates may be lower as a result, but this is not a credit you receive.
– Battery storage: The federal residential battery credit was also eliminated. Washington has limited state-level battery incentives.
Washington Solar at a Glance
| Metric | Washington State Data |
|---|---|
| Average cost per watt | $2.78/W |
| Typical 10 kW system (installed cost) | $27,800 |
| Sales tax exemption on solar equipment | Yes — state + local sales tax exempted (saves $2,500–$3,000 on most systems) |
| Property tax exemption | Yes — statewide exemption for residential solar |
| Net cost after sales tax exemption | ~$25,000–$25,300 (varies by locality) |
| Average electricity rate — Washington (2025) | $0.113/kWh |
| Average peak sun hours — Seattle | 3.7 PSH |
| Peak sun hours — Spokane | 4.8 PSH |
| Peak sun hours — Tri-Cities (Kennewick/Richland) | 5.4 PSH |
| Peak sun hours — Yakima | 5.2 PSH |
| Net metering | Full retail rate (state law through 2029) |
| Federal ITC for 2026 installations | Not available (Section 25D terminated) |
Cost data: EnergySage Washington Market Report (May 2026). Rate: EIA residential average for Washington (2025).
Cost by System Size in Washington
Washington’s combined state and local sales tax (10.25% in Seattle, 8.6–10.5% across the state) would normally be a significant added cost — but solar equipment is exempt, making the savings substantial.
| System Size | Installed Cost | After Sales Tax Exemption (~9% avg) | Annual Savings (Seattle)† | Annual Savings (Spokane)† |
|---|---|---|---|---|
| 6 kW | $16,680 | $15,178 | $900 | $1,340 |
| 8 kW | $22,240 | $20,238 | $1,200 | $1,787 |
| 10 kW | $27,800 | $25,298 | $1,499 | $2,234 |
| 12 kW | $33,360 | $30,358 | $1,799 | $2,680 |
†Seattle: 3.7 PSH × 365 × 0.80 × $0.113/kWh. Spokane: 4.8 PSH × 365 × 0.80 × $0.113/kWh. Puget Sound Energy and Seattle City Light customers may have different rate structures; verify your rate on your utility bill.
Washington Solar Incentives in 2026
Washington has strong structural protections for solar (net metering, tax exemptions) but limited direct cash incentives, particularly after the federal ITC ended.
Washington Sales Tax Exemption
Washington exempts solar energy systems from the state retail sales tax and most local sales taxes under RCW 82.08.962. At a combined state + local rate averaging 9% across Washington (10.25% in Seattle), this saves approximately $2,502 on a $27,800 system — one of the most valuable upfront savings available given Washington’s high sales tax rates.
Confirm with your installer that they are applying the exemption — some smaller installers may not be aware of the exemption or may not process it correctly.
Washington Property Tax Exemption
Under RCW 84.36.635, solar energy systems are exempt from local property tax assessment. A solar system that adds $15,000–$20,000 to your home’s assessed value will not increase your property tax bill. The exemption applies to systems on residential property and is available indefinitely.
Net Metering (Washington State Law — Through 2029)
Washington’s net metering law (RCW 80.60.030) requires utilities to credit residential solar customers at the full retail rate for excess generation. Net metering is available through December 31, 2029 under current state law. After 2029, the Washington Utilities and Transportation Commission (UTC) will determine future net metering policy. This is worth monitoring if your payback period extends past 2029.
Utility-specific notes:
– Seattle City Light: Full retail net metering. Annual true-up in April. SCL has some of the lowest rates in the US ($0.10–$0.11/kWh) — this makes Seattle an especially difficult market for solar ROI.
– Puget Sound Energy (PSE): Full retail net metering. PSE rates average ~$0.13–$0.15/kWh depending on tier.
– Avista Utilities (Spokane): Net metering available. Rates: ~$0.10–$0.11/kWh — similarly low.
– Snohomish County PUD: Net metering available. Rates similar to SCL.
Renewable Energy System Incentive Program (Expired)
Washington previously offered a production incentive through its Renewable Energy System Incentive Program, which paid a bonus per kWh produced. This program ended and is not available to new installations.
Washington Solar by Region: An Honest Assessment
Washington is two very different solar markets split by the Cascades.
| City / Region | PSH | Annual kWh (10 kW) | Annual Savings (at local rate) | Payback ($25,298 net) |
|---|---|---|---|---|
| Seattle (SCL) | 3.7 | 10,804 | $1,081 ($0.10/kWh avg) | ~23.4 years |
| Seattle (PSE customers) | 3.7 | 10,804 | $1,458 ($0.135/kWh) | ~17.4 years |
| Tacoma / Joint Base Lewis-McChord | 3.9 | 11,388 | $1,287 ($0.113/kWh) | ~19.7 years |
| Olympia / Thurston County | 4.0 | 11,680 | $1,320 | ~19.2 years |
| Spokane (Avista) | 4.8 | 14,016 | $1,542 ($0.11/kWh) | ~16.4 years |
| Tri-Cities (Kennewick/Richland/Pasco) | 5.4 | 15,768 | $1,782 | ~14.2 years |
| Yakima | 5.2 | 15,184 | $1,716 | ~14.7 years |
| Bellingham | 3.7 | 10,804 | $1,220 ($0.113/kWh) | ~20.7 years |
Seattle City Light customers have extremely low rates (~$0.10/kWh), making solar a very poor financial investment despite the city’s progressive energy reputation. This is an honest assessment — Seattle is one of the worst markets for solar ROI in the US.
Is Solar Worth It in Washington State in 2026?
Verdict: No for most western Washington homeowners; Yes for eastern Washington.
This is one of the few states where we give a “no” verdict for a significant portion of the population. Seattle City Light’s rates are among the lowest in the US — powered by Columbia River hydropower. Combining $0.10/kWh electricity with 3.7 annual peak sun hours produces payback periods of 20+ years on a system with a 25-year warranty. The math barely pencils out even under the best-case scenario.
Solar is a reasonable financial decision in Washington if:
– You live in eastern Washington (Spokane, Tri-Cities, Yakima, Walla Walla)
– You are a Puget Sound Energy customer paying $0.13+/kWh
– Your monthly bill consistently exceeds $150
– You value energy independence or battery backup (common power outages in rural WA)
– You plan to stay in your home for 15+ years
Solar is hard to justify financially in Washington if:
– You are a Seattle City Light customer paying ~$0.10/kWh
– You are in western Washington with a north-facing or shaded roof
– Your electricity bill is under $100/month
– You are planning to sell within 10 years
There is still a case beyond the finances. Washington has significant wildfire risk and outage events in eastern Washington; battery backup systems provide real resilience value. And for homeowners with high PSE rates, the calculus is materially better than for SCL customers.
What Affects Solar Cost in Washington
Western vs. Eastern WA: Eastern Washington installers see less competition from a smaller customer base, but costs remain competitive. Central and eastern Washington’s longer summer days partially compensate for lower win-season output.
Rain and snow: Western Washington’s frequent rain keeps panels clean naturally, though production is lower overall. Eastern Washington may have winter snow accumulation on panels — most modern racking systems shed snow at an angle, but low-tilt installations may require occasional manual clearing.
Utility interconnection timelines: Seattle City Light and PSE have different interconnection processes. PSE interconnections can take 3–6 months. Factor this into your planning timeline.
Battery storage: Given Washington’s relatively frequent winter power outages (especially in wooded western WA), batteries have strong resilience value even when the pure financial case is weak. Budget $10,000–$13,000 for a Tesla Powerwall 3 or Enphase IQ Battery installed.
Top Solar Companies in Washington State
| Installer | Service Area | Key Strength |
|---|---|---|
| Sunrun | Seattle/King County, Spokane | Lease/PPA options, large installer |
| A&R Solar | Seattle metro, eastern WA | Pacific Northwest specialist, strong reviews |
| Sunbridge Solar | Spokane, eastern WA | Eastern WA regional specialist |
| Elemental Energy | Seattle, Portland | B Corp certified, local PNW company |
| Puget Sound Solar | Seattle metro | Local company, 20+ years in WA |
| Northwest Wind & Solar | Wenatchee, Yakima, central WA | Rural and central WA specialist |
Compare Washington Solar Installers → Get Free Quotes
Washington State Solar FAQ
Is solar worth it in Seattle?
Financially, it’s a difficult case. Seattle City Light has some of the cheapest electricity in the US (~$0.10/kWh), and the city receives only about 3.7 peak sun hours per day on average. A 10 kW system saves roughly $1,000–$1,100/year with SCL — giving payback periods of 22–25 years on a system with a 25-year warranty. PSE customers in the Seattle area pay higher rates and see better returns (~17-year payback). If you are an SCL customer, the financial case for solar is weak without significant changes to electricity rates.
Does Washington have a solar tax credit?
Washington has no state income tax, so there are no state income tax credits for solar. The primary financial incentives are the sales tax exemption (saves $2,500–$3,000 upfront) and the property tax exemption. The federal ITC was eliminated in 2025 and does not apply to 2026 installations.
What happens to net metering in Washington after 2029?
Washington’s current net metering law runs through December 31, 2029. After that, the Washington UTC will determine future policy. There is genuine uncertainty here — California and other states have reduced net metering rates in recent years. If you are considering solar in western Washington, a 20+ year payback period that depends on post-2029 net metering policy carries meaningful risk.
Why is solar more viable in eastern Washington than western Washington?
Eastern Washington receives 4.8–5.4 peak sun hours per day (similar to parts of California), compared to 3.5–3.9 PSH in Seattle. Combined with slightly higher Avista utility rates versus SCL, eastern WA produces meaningfully better solar economics — payback periods of 14–17 years versus 20+ years in Seattle.
Sources
- EnergySage Washington Solar Market Report, May 2026
- U.S. Energy Information Administration (EIA) — Residential Electricity Rates, Washington 2025
- NREL National Solar Radiation Database — Washington peak sun hours by city
- Seattle City Light — Residential Electric Rates 2025
- Puget Sound Energy — Residential Electric Rates 2025
- Avista Utilities — Residential Electric Rates 2025
- Washington State Department of Revenue — Solar Sales Tax Exemption, RCW 82.08.962
- Washington State Legislature — Property Tax Exemption, RCW 84.36.635
- Washington State Legislature — Net Metering Law, RCW 80.60.030
- IRS — Section 25D termination per One Big Beautiful Bill Act (July 2025)
Get Free Solar Quotes in Washington →
See also: Solar Panel Cost Guide | Is Solar Worth It? | Solar Cost Calculator