Washington solar calculator

Live production from NLR (formerly NREL) PVWatts V8. Washington has full 1:1 retail net metering on PSE, Avista, Pacific Power, Seattle City Light, and Snohomish PUD (systems up to 100 kW; Grays Harbor PUD is an exception at 50% of retail). This calculator models the PSE case. Important fresh news: PSE and Seattle City Light have officially notified customers that 2026 is likely the LAST YEAR of the current 1:1 rate — they're moving to a new structure. Unlike Virginia (where the SCC preserved 1:1 in April 2026), WA utilities are actively changing it. Verify before installing. Washington has no state income tax (so no state solar credit) and the old production incentive ($0.54/kWh) has ENDED. The sales tax exemption (state + local, up to ~10% combined) is one of Washington's strongest solar incentives — saves ~$1,000+ on a typical install through Dec 31, 2029. Property tax exempt on added value. Annual settle-up resets credit on March 31 — don't oversize. Defaults: south-facing roof mount, 20° tilt, 14% losses.