Solar is one of the few home improvements where a national article is close to useless, because the variables are so local. Here is what actually decides it in Washington.
The two halves of the state
Western Washington is genuinely cloudier than most solar markets. Panels still generate — daylight rather than direct sun produces output — but annual generation is lower than in sunnier regions.
Eastern Washington is a different picture. Spokane, Yakima and the Tri-Cities get substantially more sunshine, with hot dry summers producing strong generation conditions. The Columbia Basin in particular is far better suited than its reputation as a Washington location suggests.
If you have read general Washington solar commentary and concluded it does not work, that commentary was probably describing the marine west.
Your specific roof matters more than the region
Orientation. South-facing surfaces produce most; east and west produce meaningfully less but can still work; north-facing is generally not viable.
Pitch. Affects the angle at which panels meet sunlight through the year.
Shading. The one that most often rules out otherwise suitable Washington homes. Mature conifers are characteristic of the region and they shade roofs substantially. Even partial shading affects output disproportionately depending on system design.
A proper assessment models your actual roof through the year rather than applying a regional average. Any quote not based on that is not really a quote.
Roof condition is a prerequisite
The most important practical point and the one homeowners skip.
Panels have a long service life. If your roof is approaching the end of its own — and Western Washington asphalt roofs typically run 20 to 25 years — installing panels over it means removing and reinstalling them when the roof is replaced.
That is an entirely avoidable cost. If the roof is more than halfway through its life, replacing it first is the sensible sequence.
Ask any solar contractor about roof age and condition. One who does not raise it is not thinking about your interests over the system’s lifetime.
What determines the financial case
Generation potential for your specific roof. What you currently pay for electricity, since the value of self-generated power is what you avoid buying. How much of your generation you use directly versus export. Available incentives, which change over time. How long you intend to stay.
We do not publish payback figures because they depend entirely on those variables and on rates that change. What we would say is to be sceptical of any quote presenting a confident payback period without having modelled your actual consumption pattern.
Batteries
Increasingly discussed and a separate decision. Storage lets you use generation later rather than exporting it, and provides backup during outages — which has real appeal in Washington’s windstorm-prone and rural areas.
It also adds substantial cost. Whether it makes sense depends on your outage frequency, your consumption pattern and how you value backup power independent of the economics.
Choosing a contractor
Verify registration, bond and insurance as with any work. Ask specifically about roof penetration and flashing detail — panels are mounted through your roof, and in Washington’s climate the flashing at those penetrations determines whether you get a leak in five years.
Be cautious of high-pressure sales, which are more common in this field than most. A legitimate contractor will give you time to consider a decision of this size.