Solar Panels in Washington (WA)
Last updated: February 24, 2026
Everything you need to know about going solar in Washington (WA) — costs, savings, incentives, and the best equipment for your climate.
Federal Residential Solar Tax Credit Repealed
The 30% residential solar tax credit (Section 25D) was repealed in early 2026. Homeowners who installed solar before the repeal can still claim the credit. Commercial projects retain the 30% ITC under Section 48/48E. Washington state incentives remain available.
Sun Hours/Day
3.3 hrs
Fair Solar Irradiance
8 kW System Cost
$26,400
$3.30/watt installed
Federal Residential ITC
Repealed
Section 25D (early 2026)
Annual Savings
$1,253
9,636 kWh/year
Payback Period
21.1 yrs
then free electricity for 15-20+ yrs
Solar Irradiance in Washington (2026)
Washington receives an average of 3.3 peak sun hours per day annually, equivalent to roughly 1205 kWh/m² per year of global horizontal irradiance (GHI). Summer peaks reach about 4.3 h/day, while winter lows drop to around 2.0 h/day.
This places Washington in the fair solar irradiance band compared with other US states. At 3.3 kWh/m²/day, each 1 kW of rooftop solar in Washington generates approximately 940 kWh/year (assuming 78% system performance after inverter, soiling, and temperature losses), which makes an 8 kW system produce around 9,636 kWh per year.
Data source: NREL National Solar Radiation Database (NSRDB), 1998-2020 typical meteorological year averages. Washington (WA) values reflect the statewide average; coastal, mountain, and desert microclimates can vary by ±15% from this figure.
Washington Solar Incentives (2026)
Federal residential tax credit was repealed in early 2026. Washington continues to offer the following state and utility-level programs:
| Incentive | Value | Eligibility | Deadline | Source |
|---|---|---|---|---|
| Federal Section 25D ITC | 0% (Repealed Q1 2026) | N/A | Was 12/31/2025 | IRS |
| Sales tax exemption (full) | — | — | Verify with state agency | DSIRE |
| Net metering 1:1 | — | — | Verify with state agency | DSIRE |
| Renewable Energy System Incentive | — | — | Verify with state agency | DSIRE |
⚠ Always verify state incentive deadlines, caps, and eligibility before signing a solar contract — programs change annually and many have annual funding caps that exhaust mid-year.
Major utility companies in Washington
Check your utility's net metering policy, interconnection requirements, and rate structure before installing — rules vary significantly within Washington:
- • Puget Sound Energy
- • Seattle City Light
- • Tacoma Power
- • Avista Utilities
- • Pacific Power
Each utility has different rate structures, net metering caps, and time-of-use schedules. Visit your utility's website for current solar interconnection requirements and queue times.
Net metering in Washington
Status: Net metering 1:1
Export rate: Full retail rate credit
System size cap: 100 kW; 4% of utility peak demand cap
⚠ NEM rules can be amended by state public utility commissions and individual utilities — verify with your utility before committing. Caps and rates shown reflect the most common residential tariff as of 2026.
Solar Incentives in Washington
Federal Residential ITC (Section 25D) -- Repealed
The 30% federal residential solar tax credit (Section 25D) was repealed in early 2026. Homeowners who installed solar before the repeal may still claim the credit for that tax year. Commercial solar projects continue to receive the 30% ITC under Section 48/48E.
State Incentives Available
Washington offers state-level solar incentives that remain available despite the federal ITC repeal. Check with your local utility and the DSIRE database for current programs.
Top 3 Recommended Solar Panels for Washington
With 3.3 sun hours/day, Washington homeowners need the most efficient panels to maximize every hour of sunlight:
| Panel | Wattage | Efficiency | Temp Coeff | Warranty |
|---|---|---|---|---|
| LONGi Hi-MO 7 620W | 620W | 23% | -0.28%/°C | 12/30 yr |
| LONGi Hi-MO 7 590W | 590W | 22.8% | -0.28%/°C | 12/30 yr |
| Trina Solar Vertex N+ 600W | 600W | 22.8% | -0.28%/°C | 15/30 yr |
Top 3 Recommended Batteries for Washington
Pairing solar with battery storage provides backup power during outages and can optimize savings with time-of-use rates:
| Battery | Capacity | Power | Chemistry | Warranty |
|---|---|---|---|---|
| HomeGrid Stack'd Series 38.4kWh | 38.4 kWh | 34.4 kW | LFP (Lithium Iron Phosphate) | 10 yr |
| HomeGrid Stack'd Series 28.8kWh | 28.8 kWh | 25.8 kW | LFP (Lithium Iron Phosphate) | 10 yr |
| BYD Battery-Box Premium HVM 22.1 | 22.08 kWh | 22.08 kW | LFP (Lithium Iron Phosphate) | 10 yr |
Frequently Asked Questions
How much do solar panels cost in Washington in 2026?
The average cost of an 8 kW solar system in Washington is approximately $26,400 ($3.30/watt installed). Note: The federal residential solar tax credit (Section 25D) was repealed in early 2026, so the full system cost applies unless state incentives are available. State-level incentives may reduce your out-of-pocket cost. Get 3-5 quotes from local installers for accurate pricing.
Is the federal solar tax credit available in Washington?
The federal residential solar tax credit (Section 25D) was repealed in early 2026. Homeowners who installed solar before the repeal can still claim the credit for that tax year. Commercial solar projects continue to receive the 30% ITC under Section 48/48E. Washington still offers state-level incentives that can reduce your solar costs. Consult a tax professional for the latest guidance.
Can solar panels work efficiently in Washington's climate?
Yes, solar panels work in all climates. Washington's 3.3 peak sun hours/day means choosing high-efficiency panels (21%+ efficiency) is important to maximize production. Cold temperatures actually improve panel efficiency. An 8 kW system can still produce significant savings of approximately $1,253/year.
How much can I save with solar in Washington?
An 8 kW solar system in Washington produces approximately 9,636 kWh/year, saving about $1,253 annually. The estimated payback period is 21.1 years. Over 25 years, total savings can reach $31,325.
Does Washington have net metering?
Net metering policies vary by utility in Washington. Most states offer some form of net metering or net billing that credits solar homeowners for excess electricity sent back to the grid. Contact your local utility or check the DSIRE database for current Washington net metering policies.
What is the best solar panel for Washington?
For Washington with 3.3 sun hours/day, high-efficiency panels are the best choice to maximize energy production. Look for panels with efficiency ratings above 21%.
What is the payback period for solar in Washington?
The estimated payback period for an 8 kW solar system in Washington is 21.1 years. This is calculated as: system cost ($26,400) divided by annual savings ($1,253/year). After payback, solar generates essentially free electricity for 15-20+ more years. State incentives may shorten this further.
Do I need a battery for solar in Washington?
A battery is not required for grid-tied solar in Washington, but it provides backup power during outages and can increase savings with time-of-use rate optimization. Washington's incentive programs may include battery storage rebates.
Does Washington have solar incentives?
Yes, Washington offers state-level solar incentives. These may include state tax credits, rebates, property tax exemptions, sales tax exemptions, or SRECs. The federal residential ITC (Section 25D) was repealed in early 2026. Check the DSIRE database for current programs.
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