Washington Solar Guide 2026
Everything Washington homeowners need to know: costs, incentives, net metering policy, and what makes this state unique for solar.
Quick answer
Washington solar economics depend mainly on 3.9 average peak sun hours, an estimated $2.9/W installed cost, 10.0¢/kWh electricity, and the state's current net-metering rules.
Reviewed 2026-07-26
- Best for
- Washington homeowners comparing solar costs, incentives, and payback assumptions.
- Inputs needed
- annual kWh usage, utility rate, installed $/W, net-metering policy
- Formula used
- Typical production = system kW × peak sun hours × 365.
- Source checked
- state incentive data, utility tariff checks, Wattcrunch price benchmarks
Key fact about Washington solar
Washington has the lowest electricity rates in the continental US (~$0.10/kWh) due to abundant hydropower. Solar payback is long (~14 years) — the economics improve significantly with EV charging or heat pumps added.
Peak sun hours
3.9
hrs/day avg
Avg electricity rate
10.0¢
per kWh
Median install cost
$2.9/W
before incentives
Typical payback
14 yrs
8 kW system, avg usage
Typical 8 kW system in Washington
Annual production
11,388 kWh
Year-1 savings
$1,139
System cost (est.)
$23,200
No federal tax credit — Section 25D expired December 31, 2025.
Washington Net Metering Policy
Full retail net metering (Engrossed Senate Bill 5116)
Washington requires full retail net metering. Low electricity rates (~$0.10/kWh) significantly extend payback periods, making WA one of the tougher economic cases for solar despite good policy.
Washington Solar Incentives
Available in addition to any utility rebates. Federal 25D credit is $0 for homeowner-owned systems from 2026.
- ✓Sales tax exemption on solar systems
- ✓Property tax exemption
- ✓Utility incentive programs (check local utility)
Top Utilities in Washington
Interconnection timeline: 4–10 weeks
State-specific decision guide
What to verify before signing a Washington solar quote
In Washington, the financial result depends on more than sunshine or the headline installation price. Confirm the export rule, program eligibility date, and interconnection timeline for your exact utility before treating a payback estimate as a promise.
Export value
This page models full retail net metering (engrossed senate bill 5116). Ask which tariff and export credit apply to your account, not only which program name appears in the proposal.
Incentive eligibility
Check equipment, income, installer, application, and placed-in-service rules before subtracting an incentive from the quote. Programs can close or change terms.
Interconnection
Budget for the published 4–10 weeks and confirm who pays for a required meter, service upgrade, or engineering review.
Source trail: production assumptions use NREL PVWatts; incentive discovery should be checked against DSIRE; electricity-market context is available from the EIA. Confirm final tax treatment with the IRS and your utility.
Calculate your Washington solar economics
Our calculators are pre-filled with Washington data. Run any tool below.