Washington Solar Panel Savings Calculator
Calculate how much you can save with solar panels in Washington. Based on 3.5 peak sun hours/day and 11.3¢/kWh average electricity rate.
3.5
Peak Sun Hours/Day
11.3¢
Avg Rate (¢/kWh)
15 yr
Avg Payback Period
0.8%
Solar Penetration
Calculate Your Washington Solar Savings
Average home: 6-10 kW
Your average monthly bill
South-facing is optimal
Annual Production
kWh/year
Annual Savings
per year
25-Year Savings
total estimated
Payback Period
break-even time
Monthly Savings
$58
System Cost (after ITC)
$21,000
CO2 Offset
2.6 tons/yr
Cumulative Savings vs System Cost
Washington Solar Panel Savings Overview
Washington receives an average of 3.5 peak sun hours per day, which is below the national average but still viable for solar installations. With electricity rates averaging 11.3¢ per kWh — below the national average — longer payback periods are typical but savings still add up over time. The typical Washington homeowner with a 6kW system can expect to save approximately $920 per year.
Solar Energy Production in Washington
A standard 6kW residential solar panel system in Washington produces approximately 6,132 kWh per year. This accounts for a system efficiency factor of 80%, which includes panel degradation, inverter losses, and temperature effects. While 3.5 peak sun hours is modest compared to sunbelt states, modern high-efficiency panels can still produce meaningful energy savings in Washington.
Washington Electricity Rates and Solar Context
The average residential electricity rate in Washington is 11.3¢ per kWh according to EIA data. While this rate is below the national average, electricity costs are rising approximately 2-3% per year. Over a 25-year system lifetime, your cumulative savings will still be substantial. With utility rates increasing annually, your solar savings grow each year.
Washington Solar Incentive Programs
Sales tax exemption. Net metering. Federal residential solar credit ended for 2026 homeowner-owned systems placed in service after Dec. 31, 2025. For new 2026 homeowner-owned systems, do not assume the old federal 30% residential clean energy credit unless your project has documented eligibility under current IRS guidance. Washington also offers full retail net metering, allowing homeowners to earn credits for excess solar energy sent back to the grid.
Net Metering in Washington
Washington has full retail net metering, which is a significant financial benefit for solar homeowners. Under full retail net metering, you receive credit at the full retail electricity rate for every kilowatt-hour of excess solar energy you export to the grid. This is the most favorable policy for solar homeowners.
Best Cities for Solar in Washington
The best cities for solar panels in Washington include Seattle, Spokane, Tacoma, Vancouver, Bellevue. Solar production can vary by location within the state due to differences in cloud cover, local shading, and microclimates. Southern-facing roofs with minimal shading produce the most energy. Homeowners in Seattle and Spokane can typically expect production close to the state average of 3.5 peak sun hours per day.
How Washington Compares to Neighboring States
Compared to neighboring states, Washington (11.3¢/kWh, 3.5 sun hours) receives less solar radiation but has similar electricity rates. See how solar savings compare in Oregon, and Idaho.
Methodology & Solar Energy Data Sources
How we calculate solar savings in Washington: Our solar cost, savings, and payback calculations integrate federal energy production data with state-specific incentive programs and utility rate information.
- Solar potential and production data from NREL PVWatts Calculator — the DOE's National Renewable Energy Laboratory solar energy production model for Washington.
- Electricity rates and utility data from EIA State Electricity Profiles — the definitive source for residential electricity prices by state.
- Federal residential clean energy credit information from the IRS Residential Clean Energy Credit (Form 5695) — current IRS guidance says the credit is not available for property placed in service after December 31, 2025.
- State incentive programs cross-referenced with DSIRE (Database of State Incentives for Renewables & Efficiency) — the NC Clean Energy Technology Center's authoritative incentive database.
- Carbon reduction calculations use EPA eGRID emission factors for the relevant Washington grid subregion — the official source for grid carbon intensity.
Authoritative solar and energy data sources:
- NREL PVWatts — Solar Production Model — DOE solar energy estimates by location
- EIA State Electricity Profiles — residential rates and utility data for Washington
- DSIRE — State Incentives Database — solar tax credits and rebates by state
- EPA eGRID — Grid Emission Factors — carbon intensity of Washington electricity grid
- DOE Solar Energy Technologies Office — federal solar research and cost data
- ENERGY STAR Certified Solar Inverters — efficiency standards for solar equipment
Solar Disclaimer: Savings estimates are projections based on average solar irradiance, utility rates, and incentive programs for Washington. Actual savings depend on roof orientation, shading, panel efficiency, installer pricing, and changes to net metering policies. Obtain quotes from 3+ certified installers for accurate costs. Incentive programs change frequently — verify current rates with DSIRE and your utility.
Reviewed by Brazora Monk · Last updated 2026 · NREL & EIA data current as of latest annual release
Frequently Asked Questions
How much do solar panels cost in Washington?
The average cost of a 6kW solar panel system in Washington is approximately $21,000 before documented state or utility incentives. For new 2026 homeowner-owned systems, this calculator does not subtract the old federal residential clean energy credit unless eligibility is documented. Sales tax exemption. Net metering. Federal residential solar credit ended for 2026 homeowner-owned systems placed in service after Dec. 31, 2025.
How much can I save with solar panels in Washington?
The average Washington homeowner saves approximately $920 per year with a 6kW solar system. Over 25 years, total savings can exceed $23,752, factoring in a 2.5% annual increase in electricity rates.
Does Washington have net metering?
Yes, Washington offers full retail net metering, which allows you to sell excess solar energy back to the grid. This significantly improves the financial returns of going solar.
What is the solar payback period in Washington?
Based on the inputs above, the payback period for solar panels in Washington is approximately 30.2 years before any documented state or utility incentive. After that, your solar panels generate essentially free electricity for the remaining 15-20 years of their warranty life.