Average Cost of Solar Panels in Washington State

The average cost of solar panels in Washington State is about $2.85 per watt before incentives in 2026 — close to the national average, but with a twist no other corner of the country shares. Washington pairs one of the most generous sales-tax breaks in the US with some of the cheapest electricity in the nation, so the math here is less about slashing a sky-high power bill and more about locking in a fixed energy cost for the next 25 years. A standard 8 kW residential system runs roughly $22,800 installed. Importantly, the 30% federal Investment Tax Credit (Section 25D) expired on December 31, 2025 under the One Big Beautiful Bill, so a 2026 cash or loan buyer no longer subtracts it — $22,800 is close to what you actually pay (Washington's sales-tax exemption is already baked in).

Where you live inside Washington matters more than in most states. Sun-drenched, dry Spokane in the east produces noticeably more power per panel than cloudy Seattle on the Puget Sound — and the two cities sit in different utility territories with different rates and net-metering terms. This guide breaks down 2026 prices statewide, compares Spokane and Seattle directly, walks through Washington's incentives, and shows realistic payback periods so you can decide whether solar pencils out for your home.

Washington solar cost by system size (2026)

The right system size depends on your annual electricity use. The average Washington home uses roughly 11,000–12,000 kWh per year — higher than the national average because many homes heat with electricity. The table below shows typical 2026 installed prices statewide at $2.85 per watt. Because the 30% federal tax credit expired after 2025, the 2026 column is what most cash and loan buyers now pay; the final column shows what the same system cost net through 2025, when the credit still applied, so you can see the difference. Remember that Washington's sales-tax exemption already applies to every figure below, so there is no 8–10% sales tax stacked on top the way there would be in most states.

Figures are Washington averages at $2.85/watt. Real quotes vary ±15% with roof type, shading, panel brand, and installer. Adding a home battery typically adds $9,000–$15,000. The "was, with 2025 federal credit" column is shown for reference only — the 30% credit is no longer available for 2026 installations.

Methodology: Washington per-watt and system-cost figures are 2026 market averages compiled from installer quote platforms and published solar pricing reports (e.g. EnergySage and industry cost surveys), with the state's sales-and-use tax exemption applied; peak-sun-hour and output figures use typical published regional data (e.g. NREL). These are planning estimates, not binding quotes — actual prices vary by installer, roof, and equipment, so get three local quotes. Last updated June 2026.

Solar panel cost in Spokane

Spokane is quietly one of the better solar markets in Washington. Installed prices run about $2.80 per watt in 2026, so a typical 8 kW system is roughly $22,400 installed (the 30% federal credit expired after 2025, so 2026 buyers no longer subtract it). The real advantage is sunshine: eastern Washington sits in the rain shadow of the Cascades, so Spokane is dry and clear far more often than the Puget Sound, averaging around 4.2 peak sun hours per day. That means a Spokane array out-produces an identical system near Seattle by roughly 10–15% over a year.

Most of Spokane is served by Avista Utilities, whose residential rates (around $0.10–$0.11 per kWh) are slightly higher than the deeply subsidized hydropower rates on the west side. More sun plus marginally higher rates means Spokane homeowners typically see the shortest payback in the state — generally 18–23 years for a solar-only system now that the 30% federal credit has expired. Avista was still offering retail-rate net metering to new solar customers in 2026, so excess summer production banks as credits you draw down through the darker months. For a full city breakdown with a Spokane-tuned payback calculator, see our dedicated guide to solar panel cost in Spokane, WA.

Solar panel cost in Seattle & the Puget Sound

Seattle solar installs at roughly $2.90 per watt, a touch above the state average because installers price in the steeper, more complex roofs and tree shading common in the region. The headwind here isn't price — it's the value of what you're offsetting. Seattle City Light sells some of the cheapest electricity in the United States (around $0.12 per kWh) thanks to carbon-free hydropower, and Tacoma Power is cheaper still. Cheap power is great for your wallet but — with the 30% federal credit gone in 2026 — stretches solar payback to roughly 19–24 years.

Seattle also gets fewer peak sun hours (about 3.7 per day) than Spokane, so the same panels make less electricity. None of this means solar is a bad idea on the west side — it generates reliably from diffuse daylight, shields you from future rate hikes, and pairs naturally with an EV or a battery for outage protection. It simply means Seattle and Tacoma homeowners should size systems to their own usage and treat solar as a long-term hedge rather than a fast financial win. Customers of Puget Sound Energy, which serves Bellevue and much of the suburban Puget Sound, sit between the two extremes on both rates and payback.

Washington solar cost & payback by city (2026)

Because utility rates and sun hours vary so much across the state, payback is the number worth comparing — not just the sticker price. Here's how the major Washington markets stack up for a typical 8 kW system.

Payback estimates assume a solar-only system at the full 2026 installed cost (the 30% federal credit expired after December 31, 2025) and current retail net metering. Adding a battery, an EV, or anticipated rate increases shortens these ranges.

Washington solar incentives in 2026

Washington's incentive mix is unusual: there's no state income tax, so there's no state tax credit — but the state makes up for it with a sales-tax break that quietly saves thousands.

Sales-and-use tax exemption

Washington exempts qualifying solar energy systems from state and local sales and use tax. On a $22,800 system, skipping 8–10% sales tax saves roughly $1,800–$2,300 outright — money buyers in most other states simply pay. The exemption applies to residential rooftop systems and has been extended by the legislature into the latter half of the decade; confirm the current cap and end date with your installer.

Federal tax credit — expired after 2025

Through December 31, 2025, the federal Residential Clean Energy Credit (Section 25D) let homeowners deduct 30% of a system's cost — including a battery — worth about $6,840 on a $22,800 system. The One Big Beautiful Bill, signed July 4, 2025, ended that credit for systems placed in service after 2025. A Washington system installed in 2026 with cash or a loan gets no federal credit, which is why 2026 paybacks are several years longer than they were last year. (Solar leases and PPAs may still benefit from a separate business clean-energy credit through 2027, which can lower monthly payments.)

Net metering

Washington law requires utilities to offer net metering, crediting the excess power your panels export at the retail rate so summer overproduction offsets winter consumption. Puget Sound Energy, Avista, Seattle City Light, and Tacoma Power all offered it to new customers in 2026, though each runs its own program cap and annual true-up date.

Factors that affect your Washington solar price

Two Washington homes can get very different quotes for the same nominal system size. The biggest drivers here are:

• Region and sun hours: An eastern-Washington roof in Spokane produces more per watt than the same array in cloudy Seattle, changing the size you need to hit your usage.
• Utility and net-metering terms: Avista, PSE, Seattle City Light, and Tacoma Power each set rates and net-metering caps that change how much a system saves you.
• Roof complexity and trees: Steep pitches, multiple roof planes, and the heavy tree cover common west of the Cascades raise labor and may require shade-tolerant microinverters.
• Battery storage: Adding a battery for winter outage protection is usually the single largest line-item swing in a Washington quote.
• Panel and inverter tier: Premium high-efficiency panels cost more per watt but produce more on smaller or shaded PNW roofs.
• Installer competition: Washington's installer market is thinner than California's, so getting three quotes matters even more — it routinely saves $2,000–$4,000.

Is solar worth it in Washington?

It depends on what you want from it. If you're chasing the fastest possible payback, Washington's cheap hydropower — and the expiry of the 30% federal credit after 2025 — makes that roughly 18–24-year horizon longer than in high-rate states like California or Massachusetts. But solar is still worth it for a large share of Washington homeowners: it locks in a fixed energy cost against future rate increases, Washington's sales-tax exemption still trims the upfront price meaningfully, and pairing solar with an EV or a heat pump — both common in Washington — sharply improves the economics by letting you use more of your own production. Add a battery and you also gain resilience against the windstorm outages the region sees every winter. For homeowners planning to stay put for a decade or more, Washington solar is a sound long-term investment, even if it isn't the overnight bill-killer it is in sunnier, pricier states.

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