Solar resource
Your solar production in Seattle
3.57 avg peak sun hours/day
Monthly avg solar radiation (kWh/m²/day) — Austin, TX. Bars update to show estimated kWh production when you use the calculator above.
Utility rate
Seattle City Light electricity rate
$0.097/kWh residential
- Utility
- Seattle City Light
- Residential rate
- $0.097/kWh (blended)
Seattle City Light (SCL) is a publicly owned utility that derives most of its power from Pacific Northwest hydropower, keeping rates among the lowest in the nation. SCL uses tiered residential pricing with a basic service charge. The blended $0.097/kWh reflects typical usage across both tiers. Washington's net metering statute (RCW 80.60) requires SCL to credit excess solar generation at the full retail rate on a monthly basis, with annual true-up. This full retail-rate credit makes every offset kWh worth the same $0.097 whether self-consumed or exported. SCL's low rates reduce solar payback speed relative to higher-cost utilities, but the Washington Sales Tax Exemption and strong net metering partially offset this.
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Incentives
Available solar incentives in Seattle, WA
Federal + state + utility
| Incentive | Type | Value | Scope |
|---|---|---|---|
| Federal Solar Investment Tax Credit (ITC) | Tax Credit | 30% of system cost | Federal |
| Washington State Sales Tax Exemption on Solar | Exemption | Full retail sales tax exemption on solar equipment and installation (≈10.25% in Seattle) | State |
| Washington Net Metering (Full Retail Rate) | Net Metering | Full retail rate credit for exported solar energy | Utility |
| Washington Solar Property Tax Exemption | Exemption | 100% of added home value from solar system | State |
Incentive amounts and eligibility rules change. Verify current terms with your installer and a tax professional before installation.
System cost
Cost breakdown (6 kW default)
- Gross system cost
- $17400
- Federal ITC (30%)
- −$5220
- Net system cost
- $12,180
- Installed cost per watt
- $2.9/W
Lawrence Berkeley National Laboratory Tracking the Sun 2024 — Pacific Northwest/Washington median installed cost for systems 3–10 kW
Payback & long-term value
25-year outlook
- Annual savings (yr 1)
- $581
- Simple payback period
- 21.0 years
- 25-year net savings
- $6400
- Assumed annual rate increase
- 2.0%/year
25-year estimate uses flat electricity rate for conservative baseline. Accounting for 2.0% annual rate increases, lifetime savings increase substantially.
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How it works
How solar savings work in Seattle
- Your panels capture sunlight Solar panels convert sunlight into DC electricity. Seattle averages 3.57 peak sun hours per day annually — the lowest of any city in our calculator, but often underestimated. Seattle's secret advantage: long summer days (June–August) deliver 5.6–6.5 kWh/m²/day, comparable to many sunnier cities. The challenge is winter, when December averages just 0.93 kWh/m²/day. A well-sized system banks summer credits to offset those winter bills under Washington's full retail-rate net metering law.
- An inverter converts DC to AC A solar inverter converts the DC power from your panels into the AC electricity your home uses. Modern string inverters and microinverters achieve 96–99% conversion efficiency. Seattle's cool, mild temperatures are actually ideal for solar panels — photovoltaic cells are more efficient in cooler weather, partially compensating for lower irradiance. Even Seattle's overcast skies produce measurable diffuse irradiance that panels convert to electricity.
- You use solar power instead of buying from Seattle City Light Every kilowatt-hour (kWh) your system produces during daylight reduces what you buy from Seattle City Light at $0.097/kWh. A 6 kW system produces about 5,985 kWh/year in Seattle — concentrated in spring and summer. Seattle homes typically use 600–900 kWh/month due to the mild climate and widespread use of electric heating, so a 6 kW system can offset a significant share of annual usage through net metering.
- Summer surplus builds credits for winter bills From April through September, your panels will likely produce more energy than your home uses. Under Washington's net metering law (RCW 80.60), Seattle City Light credits that exported energy at the full retail rate of $0.097/kWh. Monthly credits carry forward, and SCL reconciles annually — so strategically sizing your system to generate a useful summer surplus while avoiding large annual true-up forfeitures is key to maximizing Seattle solar economics.
- You claim the federal tax credit and Washington exemptions In the year your system is installed, you claim the 30% federal tax credit — $5,220 on a $17,400 system — reducing your net cost to $12,180. Washington's Sales Tax Exemption (RCW 82.08.962) means you pay no state or local sales tax on your solar equipment or installation, saving roughly $1,600–$1,800 at Seattle's 10.25% combined tax rate. Washington's property tax exemption (RCW 84.36.635) prevents the added home value from raising your property taxes.
- Your savings grow as Seattle City Light rates rise Seattle's longer payback period (~21 years) reflects honest economics in a low-rate, cloudy climate — but the 25-year outlook is positive. As Seattle City Light rates rise (historically ~2%/year due to infrastructure investment), every kWh your system produces is worth more. Over 25 years, a 6 kW Seattle system nets roughly $6,400 after repaying the installation cost. Stacking the sales tax exemption (~$1,700 savings) brings the effective payback closer to 18–19 years.
FAQ
Common solar savings questions for Seattle, WA
Is solar worth it in Seattle, WA given the clouds and rain?
Yes, but with realistic expectations. Seattle averages 3.57 peak sun hours per day — the lowest among major U.S. cities — but that figure hides a highly seasonal pattern. Seattle's April–September period delivers 4.4–6.5 kWh/m²/day, rivaling much sunnier cities. Washington's full retail-rate net metering (RCW 80.60) allows summer surplus to offset winter bills directly. Combined with the 30% federal ITC, Washington's sales tax exemption (saving ~$1,700 on a 6 kW system), and Seattle City Light's low-but-rising rates, solar does generate a positive 25-year return. The payback period is longer (~18–21 years after incentives) than in sunnier markets, but Seattle homeowners planning to stay long-term or prioritizing energy independence find it worthwhile.
What solar incentives are available in Seattle, WA?
Seattle-area homeowners can stack multiple incentives: (1) the 30% federal Investment Tax Credit (ITC) through 2032 — $5,220 on a $17,400 system; (2) Washington's Sales Tax Exemption (RCW 82.08.962), which eliminates the ~10.25% combined sales tax on solar equipment and installation, saving roughly $1,600–$1,800 on a 6 kW system; (3) Washington's full retail-rate net metering (RCW 80.60) with monthly credit carryforward and annual true-up through Seattle City Light; and (4) Washington's Solar Property Tax Exemption (RCW 84.36.635), which prevents the added home value from raising property taxes.
What is Seattle City Light's net metering policy?
Washington law (RCW 80.60) requires Seattle City Light to offer net metering at the full retail electricity rate. Monthly surplus credits accumulate throughout the year. Seattle City Light reconciles credits annually — unused credits at the end of the annual period may be forfeited or credited at a reduced rate, so sizing your system to avoid large annual surpluses is important. Within each month, exported excess solar is valued the same as power you'd otherwise purchase at $0.097/kWh. Washington's full retail-rate policy is significantly more favorable than utilities that use a lower 'avoided cost' credit rate.
What is the Washington State solar sales tax exemption?
Washington RCW 82.08.962 and 82.12.962 exempt residential solar energy systems from Washington state and local retail sales and use taxes through December 31, 2029. Seattle's combined state and local sales tax rate is approximately 10.25%, so on a $17,400 system, the exemption saves roughly $1,784 compared to a taxable purchase. The exemption applies to both the equipment and the installation labor in qualifying turnkey contracts. Your solar installer should document the exemption and not charge sales tax — no separate application is required from the homeowner.
How much does a solar system cost in Seattle?
A 6 kW system in Seattle costs approximately $17,400 before incentives ($2.90/watt installed, per Lawrence Berkeley Lab 2024 Pacific Northwest data). The Washington Sales Tax Exemption (RCW 82.08.962) is already factored into this price — without it, you'd pay an additional ~$1,784 in sales tax. After the 30% federal ITC ($5,220), the net cost is about $12,180. Prices vary by installer, equipment tier, roof complexity, and permit requirements. Seattle permit fees for solar are typically $150–$500.
How much solar energy does Seattle get compared to other cities?
Seattle averages 3.57 peak sun hours per day — less than Portland (4.04), Denver (5.57), Austin (5.07), or Phoenix (5.79). A 6 kW system produces about 5,985 kWh/year in Seattle vs. 7,200 in Portland, 9,240 in Denver, or 14,700+ in Phoenix. However, Seattle's highly seasonal production profile means smart system sizing and Washington's strong net metering policy are critical to making Seattle solar financially viable. The good news: Germany, a world leader in solar, gets less sun than Seattle.
How many solar panels do I need for my Seattle home?
A typical Seattle home using 600–900 kWh/month (lower than southern cities due to mild climate) generally needs a 5–8 kW system. A 6 kW system (about 14–16 panels at 380–440 W each) covers a significant portion of annual consumption through net metering credits. Because Seattle's production is highly seasonal — roughly 70% of annual output comes from April–September — sizing to generate a useful summer surplus is more important than matching monthly usage. Use the calculator above to estimate based on your Seattle City Light bill.
Sources
Data sources and freshness
- https://pvwatts.nrel.gov/
- https://openei.org/apps/USURDB/
- https://www.eia.gov/electricity/data/browser/
- https://www.seattle.gov/city-light/residential-services/rates
- https://app.leg.wa.gov/rcw/default.aspx?cite=80.60
- https://app.leg.wa.gov/rcw/default.aspx?cite=82.08.962
- https://app.leg.wa.gov/rcw/default.aspx?cite=84.36.635
- https://emp.lbl.gov/tracking-the-sun
- https://www.energy.gov/eere/solar/homeowners-guide-federal-tax-credit-solar-photovoltaics
- https://dsireusa.org/
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Disclaimer: This calculator provides estimates for informational purposes only — not financial or investment advice. Solar savings depend on actual shading, roof orientation, energy usage patterns, rate changes, and equipment performance. Consult a licensed installer and a tax professional before making purchasing decisions. Verify incentive eligibility with official sources. Data last verified 2026-04-13.