Complete Guide to Solar Energy in Washington
Your complete resource for solar energy. Everything you need to know about solar laws, solar costs, solar financing, and solar installation in Washington.
Why Washington is a Strong Solar Market
Better Solar Than You Think
Washington receives 152 sunny days and 88 partly sunny days annually. Seattle averages 3.8 peak sun hours daily—more than much of the Northeast. Eastern Washington sees 4+ peak sun hours. Modern panels work efficiently in diffuse light, and long summer days align with peak electricity usage.
Rising Utility Rates
Washington residential rates average 14.06¢/kWh. PSE proposes a 9.30% increase in 2026 (~$11/month more). Avista seeks a 13.9% residential rate increase starting 2027, with cumulative increases through 2030. Solar locks in predictable energy costs for 25+ years.
Sales Tax Exemption Through 2029
100% sales tax exemption on solar systems up to 100 kW (8-9% savings). Covers all equipment and installation costs. Available through December 31, 2029. Larger systems (101-500 kW) receive 50% exemption.
Strong Net Metering Policy
Washington mandates 1:1 net metering through major utilities (PSE, Avista, Seattle City Light). Excess summer production credits offset winter usage. Current net metering structure may change after 2026 as utilities approach capacity caps—making 2026 critical for installation.
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Laws & Regulations
Washington Solar Rights Law (RCW 64.38.055) prohibiting HOA bans, sales tax exemption through 2029 (100% for systems ≤100 kW), property tax exemption for residential installations, net metering policies, interconnection standards, Washington Solar Consumer Protection Act.
Residential Solar
Complete guide for homeowners covering system sizing for Pacific Northwest climate (8-9kW typical), high-efficiency panels optimized for diffuse light and cloudy conditions, microinverters vs. string inverters for variable weather, roof requirements for rain and occasional snow, benefits of battery storage for net metering optimization.
Costs & Savings
2026 pricing breakdown ($2.77/watt average), cost analysis by utility provider (PSE, Avista, Seattle City Light, Snohomish PUD), sales tax exemption savings (8-9%), payback period estimations (8-12 years with net metering), lifetime savings exceeding $40,000 over 25 years despite cloudy reputation.
Financing Options
Solar loans with competitive rates (4.5%-9% APR typical), lease agreements, Power Purchase Agreements (PPAs), sales tax exemption optimization, utility-specific rebate programs where available.
Installation Guide
Choosing NABCEP-certified Washington installers, understanding permit requirements across 39 counties, navigating HOA processes under RCW 64.38.055 protections, installation timeline for Pacific Northwest weather, utility interconnection with PSE/Avista/SCL, obtaining Permission to Operate (PTO), Washington Solar Consumer Protection Act compliance.
Solar 101
Fundamentals of photovoltaic technology for cloudy climates, understanding monocrystalline panel performance in low-light conditions, inverter types optimized for variable generation, system monitoring, maintenance requirements including debris removal, moss prevention, winter performance optimization.
Community Solar
Emerging community solar opportunities in Washington, utility-specific programs, shared solar gardens for renters and multi-family residents unable to install rooftop systems, subscription-based models (availability varies by utility territory), legislative developments supporting expanded community solar access.
Solar Calculator
Estimate your solar savings and system requirements.
Quick Solar Savings Calculator
Important 2026 Updates
Net Metering at Critical Juncture
Several Washington utilities are approaching mandated net metering capacity caps. PSE and Seattle City Light may modify compensation rates after 2026. Current 1:1 net metering structure allows full retail credit for excess generation—future changes could significantly reduce solar economics. Installing before policy changes maximizes lifetime value.
Learn more: WA Dept of Commerce - Net Metering | WASEIA Net Metering Resources
Utility Rate Increases Accelerate
PSE proposes 9.30% electricity rate increase in 2026 (~$11/month increase). Avista filed for 13.9% residential rate increase starting January 2027, with additional increases through 2030. Rising rates improve solar payback periods and long-term ROI. Solar installation locks in energy costs against future utility increases.
Learn more: WA Utilities & Transportation Commission | Track Rate Cases
Washington Solar Laws & Regulations
Federal Tax Credit
The federal tax credit ended at the end of 2025, but only for residential solar installations. Commercial solar projects may still qualify for the 30% tax credit if they begin construction latest by July 4, 2026 or become operational before the end of 2027.
Learn more: IRS Solar Tax Credit
Solar Rights Law (RCW 64.38.055)
Washington law prohibits HOAs from banning solar panel installations on owner or resident property. HOAs may establish reasonable guidelines for placement and appearance but cannot create prohibitive restrictions. One of the strongest solar access protections in the nation.
Learn more: RCW 64.38.055 | Solar Washington - HOA Guide
Sales Tax Exemption (Through 2029)
100% state and local sales tax exemption for solar systems up to 100 kW (saves 8-9% statewide). Covers all equipment and installation costs. Available through December 31, 2029. Systems 101-500 kW receive 50% exemption. One of the most valuable state-level incentives in the Pacific Northwest.
Learn more: WA Dept of Revenue - Solar Exemption | DSIRE Washington