When Is the Best Time to Go Solar in Washington State?
Washington State might not be the first place that comes to mind when you think about solar energy. Gray skies and rainy winters are practically part of the state's identity. But here's the thing — Washington homeowners are going solar in record numbers, and for good reason. Between federal tax credits, net metering policies, and dropping equipment costs, the question isn't really if you should go solar. It's when.
This guide breaks down the best timing for a residential solar installation in Washington, so you can make a smart, informed decision.
Does Washington Get Enough Sun for Solar to Work?
The short answer: yes. Solar panels don't need scorching heat — they need daylight, and Washington gets plenty of it. The eastern side of the state (think Spokane, the Tri-Cities, and the Yakima Valley) averages 300+ sunny days per year, making it an excellent solar market. Western Washington, including Seattle and Tacoma, averages around 4 to 4.5 peak sun hours per day during summer months.
Modern solar panels are also more efficient in cooler temperatures. Extreme heat can actually reduce panel output, so Washington's mild climate works in your favor.
The Best Season to Start Your Solar Install in Washington
Spring and Early Summer: The Sweet Spot
If you want your system producing power as soon as possible, spring (March–May) is the ideal time to start the process. Here's why:
- Longer days are coming. By getting your system installed and connected in spring, you capture the highest-output months — June, July, and August — right away.
- Contractor availability is better. Summer is peak season for solar installers. Starting in spring means you're ahead of the rush and may get faster scheduling and more competitive quotes.
- Permitting takes time. From your first quote to a fully permitted, utility-connected system, the process typically takes 4 to 12 weeks in Washington. Starting in spring means you're online before peak sun.
Fall: Still a Smart Window
Fall installations (September–November) make sense if you missed the spring window. You won't capture peak summer output, but you'll be positioned to benefit from net metering credits that carry over through the lower-production winter months.
Winter: Slow But Not Off the Table
Winter installs happen, and some homeowners actually get better pricing and faster turnaround because demand is lower. Your system will produce less in December and January, but those months will be covered by credits you banked over the summer — assuming you're on a net metering plan.
Key Incentives That Affect Your Timing
Washington has a strong incentive environment, and some of these are time-sensitive.
Federal Investment Tax Credit (ITC): As of 2025, homeowners can claim 30% of their total system cost as a federal tax credit. This credit is currently scheduled to step down in future years under current law, so the sooner you install, the more you benefit. Confirm current rates with a tax professional.
Washington State Sales Tax Exemption: Washington offers a sales and use tax exemption on solar energy systems and installation. This is a meaningful upfront saving — Washington's state sales tax is 6.5%, plus local rates. This exemption is set to expire, so check with your installer or the Washington Department of Revenue for the current status.
Net Metering in Washington: Under Washington's net metering law, your utility must credit you for excess power your system sends to the grid. These credits offset your bill during low-production months. Locking into net metering sooner means you start banking credits earlier.
Utility and Local Incentives: Some Washington utilities and municipalities offer additional rebates or incentives. Check with your specific utility — programs vary by provider.
How Long Does the Process Take in Washington?
Expect the timeline from first contact to a powered-on system to look something like this:
- Get quotes: 1–2 weeks
- Choose an installer and sign a contract: 1 week
- System design and permitting: 2–6 weeks (varies by county)
- Installation: 1–3 days for most residential systems
- Utility interconnection approval: 1–4 weeks
Total: 6 to 14 weeks is typical. Plan accordingly if you want to be generating power by a specific date.
What to Look for in a Washington Solar Installer
Not all solar companies operate the same way. When comparing options:
- Look for NABCEP-certified installers
- Ask about workmanship warranties (10–25 years is standard)
- Confirm they handle permitting in your county
- Get at least two or three competing quotes
- Ask how they handle utility interconnection paperwork
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FAQ
H3: Is solar worth it in Seattle or western Washington?
Yes — even in cloudy western Washington, solar systems deliver a positive return over their lifetime. The federal tax credit, sales tax exemption, and net metering rules make the economics work even with lower sun hours. Modern panels are efficient enough to produce meaningful power on overcast days.
H3: How much can I save with the federal solar tax credit in Washington?
The federal ITC currently allows you to deduct 30% of your system cost from your federal taxes. On a $20,000 system, that's a $6,000 credit. Exact savings depend on your tax liability and system cost — confirm specifics with a tax professional.
H3: Will Washington's sales tax exemption for solar expire?
The exemption has been renewed by the state legislature several times, but it is not permanent. Always verify the current status with the Washington Department of Revenue or your installer before making a decision based on this benefit.
H3: What if I have a homeowners association (HOA) in Washington?
Washington law (RCW 64.38.055) limits an HOA's ability to outright prohibit solar energy systems, though they may impose reasonable aesthetic guidelines. If your HOA has concerns, they cannot ban solar entirely under state law.
H3: How do I know if my roof is ready for solar?
Most installers offer a free site assessment. Key factors include roof age, pitch, shading from trees or nearby buildings, and structural integrity. A roof with less than 5–7 years of life left is often replaced before installing solar.
The Bottom Line
The best time to go solar in Washington is the one that lets you lock in current incentives, capture peak summer production, and avoid contractor backlogs. For most homeowners, that means starting the process in late winter or early spring. But any time of year can work — the sooner you start gathering quotes, the sooner you'll have real numbers to evaluate.
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