Solar in Washington: Cloudy Skies, Surprisingly Decent Returns

Washington state gets a reputation for rain and gray skies. Seattle averages 152 cloudy days per year. So when someone says they are considering solar in Washington, the first reaction is usually skepticism.

Here is the thing — Washington has some of the strongest net metering laws in the country, no state income tax to complicate credits, and electricity rates that have been climbing steadily. Germany gets less sun than Washington and leads Europe in solar. The clouds are not the real issue. The math is.

The Good News

Excellent Net Metering

Washington mandates net metering for all utilities, including investor-owned utilities like Puget Sound Energy and Avista, plus municipal utilities and co-ops. You get credited at the full retail rate for excess production. Credits roll over month to month, and unused credits at the end of the annual cycle are typically granted to the utility — so system sizing matters.

This is a major advantage. Full retail net metering means your summer overproduction (Washington gets long sunny days June through September) offsets your winter electricity costs when production drops.

Sales Tax Exemption

Washington exempts solar panels, inverters, and batteries from the 6.5% state sales tax (plus local taxes that can push the effective rate to 10%+). On a $28,000 system, this saves $1,820-$2,800 depending on your local tax rate. That is a meaningful upfront discount.

No State Income Tax

Washington has no state income tax, which means no state solar tax credit either. But it also means the lack of a federal ITC does not stack with a missing state credit — you are only missing one incentive, not two.

Strong Summer Production

Western Washington gets 4.0-4.5 peak sun hours averaged annually, but the seasonal swing is dramatic. June and July deliver 6-7 peak sun hours per day. Eastern Washington (Spokane, Tri-Cities) averages 4.5-5.2 peak sun hours annually — genuinely good solar territory.

The Challenges

Low Winter Production

November through February, Western Washington gets 1.5-2.5 peak sun hours per day. Your panels will produce 60-70% less in winter than summer. Net metering banking from summer helps, but you should expect your panels to cover only 20-40% of your winter electricity needs directly. A monitor like the Sense Energy Monitor helps you track exactly how much your panels produce season to season, so you can verify your system is performing as expected.

Already Low Electricity Rates

Washington has some of the cheapest electricity in the country thanks to hydroelectric power. The average residential rate is $0.11-$0.13/kWh — significantly lower than the national average of $0.16/kWh. Lower rates mean lower savings per kWh produced, which extends the payback period.

This is the single biggest headwind for Washington solar. Your panels produce reasonably well, but each kWh saved is worth less than in high-rate states.

No State Tax Credit or Rebate

The old Washington state solar production incentive program expired. There is currently no state tax credit, rebate, or SREC market. The sales tax exemption is the only state-level incentive.

The Washington Solar Math (2026)

Typical 8kW system (Western WA):

• Installed cost: $27,200 ($3.40/watt — Pacific NW market)
• Federal ITC: $0 (expired January 1, 2026)
• State credits: $0
• Sales tax savings: ~$2,450 (varies by county)
• Net cost: ~$24,750

Annual production: ~8,800 kWh (Western WA), ~10,500 kWh (Eastern WA)

Average rate: $0.12/kWh

Annual savings: $1,056 (Western), $1,260 (Eastern)

Payback period (Western WA): ~23 years at flat rates, ~18 years with 4% annual rate increases

Payback period (Eastern WA): ~20 years at flat rates, ~15 years with rate increases

25-year savings: $8,000-$18,000

These numbers are honest and they are longer than most states. Washington solar works, but it is a slower return.

When Solar Makes Sense

Install if:

• You are in Eastern Washington with better sun and higher rates
• Your electricity bill is $150+ monthly (suggesting higher-than-average consumption)
• You plan to stay 15+ years and value energy independence
• You are motivated by environmental goals alongside financial return
• You have a south-facing roof with clear exposure

Wait or skip if:

• Your electricity bill is under $100/month (hard to justify the investment)
• You are in a heavily shaded location in Western Washington
• You expect to move within 7-8 years
• Financial payback is your only motivation — the timeline is long in this state

Key Takeaways

• Full retail net metering is mandated statewide — this is Washington's strongest solar policy
• Sales tax exemption saves $1,800-$2,800 upfront depending on local rates
• No federal or state tax credit in 2026 makes the math harder than pre-2026
• Low electricity rates ($0.11-$0.13/kWh) extend payback compared to high-rate states
• Eastern Washington gets significantly more sun and has better solar economics
• Typical payback: 15-23 years depending on location and rate assumptions
• Washington solar is a long-term play — it works, but patience is required
• Summer overproduction banked through net metering is essential to the economics

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