Computed from 39 recent building-permit filings in Seattle, WA — what people actually declared, not survey guesses.
Typical low · P25$19,330
Median$33,824
Typical high · P75$40,000
✓ Verified from 39 recent building-permit filings in Seattle, WA
Every filing behind this range declared a residential renovation cost between $1,000 and $2,000,000 — outliers and commercial-scale projects are excluded. We only publish a range once at least 30 qualifying filings exist for a city/project combination; this one has 39.
Data refreshed September 2026
The short answer: a typical solar installation in Seattle costs around $33,824, with half of all projects landing between $19,330 and $40,000. If a quote falls well outside that range, it isn't automatically wrong — but it deserves an explanation you can understand.
Seattle-specific factors
Seattle's older housing stock (many homes pre-date modern energy codes) means insulation, moisture control and code-required upgrades surface often once a permit triggers inspection.
High year-round rainfall makes exterior work — roofing, decks, additions — weather-dependent, and correct flashing/moisture detailing matters more here than in drier climates.
How to use this solar installation range
The middle half of the published sample spans $19,330 to $40,000. That is a 61% spread around the median, so the details of your scope matter more than the label on the project.
What this project can cover
Solar installation usually covers panels, inverters, mounting, wiring, and grid connection work; battery storage is a separate major choice.
What may sit outside it
Roof replacement, structural reinforcement, service upgrades, batteries, and monitoring subscriptions may sit outside the basic panel scope.
Use your quote to test the range
Compare system size, expected annual generation, and price per kW.
Confirm the roof condition and mounting warranty.
Ask for the assumptions behind savings and export estimates.
This guide is based on 39 qualifying permit filings, not completed projects. Permit values reflect what applicants declared and can differ from the final paid cost.
Before you spend on a solar installation
💸 What drives the cost
System size (kW) and panel count — but price per kW falls as systems grow
Battery storage can add 40–80% to the total; it's a separate decision from panels
Roof condition and orientation: re-roofing first is cheaper than removing and re-mounting panels later
✂️ How to spend less
Get quotes in price-per-kW to compare like for like
If your roof is over ~15 years old, replace it before, not after, installation
Check export tariffs (UK SEG) and local incentives before sizing the system
🚩 Red flags when hiring
Lease/PPA structures pitched without showing the total cost of ownership vs buying outright
Savings projections assuming electricity prices rising 8–10% every year
Next steps for your solar installation
Get contractor quotes
Compare proposals from vetted professionals in your area. Free, no-obligation quotes.
Every figure on this page is computed from declared valuations on building permits filed with Seattle Department of Construction and Inspections (SDCI), published via the Seattle Open Data Portal. We report the 25th percentile, median and 75th percentile of 39 recent residential filings — never a single-point "average". Declared values are what applicants file, not final invoices, so treat the range as planning guidance rather than a quote. Full methodology →
Check the underlying public records
The source dataset is maintained by Seattle Department of Construction and Inspections (SDCI). The published sample is the subset classified as residential, matched to this project type, and carrying a declared valuation from $1,000 to $2,000,000. The count above is the number of qualifying filings used for this city and project, not the number of homes or completed invoices.
How much does a solar installation cost in Seattle?
Based on 39 recent building-permit filings with Seattle Department of Construction and Inspections (SDCI), the median declared cost is $33,824. Half of all projects fall between $19,330 and $40,000.
Are these figures quotes?
No. Permit valuations are what applicants declare to Seattle Department of Construction and Inspections (SDCI) when filing, not final invoices — and Seattle Department of Construction and Inspections (SDCI) doesn't independently verify the declared value. Treat the range as planning guidance and a sanity-check against the quotes you receive, not a price to hold a contractor to.
Why is the range so wide for Seattle?
Seattle's older housing stock (many homes pre-date modern energy codes) means insulation, moisture control and code-required upgrades surface often once a permit triggers inspection. That local variation is on top of the usual differences in size and specification, which is why we publish the 25th percentile, median and 75th percentile instead of a single misleading "average" — you can see where a quote sits in the real distribution.
Planning something else, or somewhere else? Request a city or project — requests decide what we ingest next.