Idaho vs Washington Solar Incentives: Which State Gets the Better Deal?
Side-by-side comparison of Idaho and Washington solar incentive programs in 2026: state tax credits, net metering rules, exemptions, payback period, and projected 25-year savings.
| Metric | ID · Idaho | WA · Washington |
|---|---|---|
| Avg Monthly Bill | $115 | $110 |
| Peak Sun Hours / Day | 5 ◆ | 3.8 |
| Avg $/Watt Installed | $2.8 ◆ | $2.85 |
| State Tax Credit | None | None |
| Net Metering | avoided-cost | retail |
| SREC Market | No | No |
| Property Tax Exempt | No | No |
| Sales Tax Exempt | No | Yes |
| Payback, pre-credit model (yrs) | 10.2 | 9.8 ◆ |
| 25-yr savings, pre-credit model | $24,800 | $26,200 ◆ |
Payback and 25-year savings were modeled while the federal residential credit applied. They are not a 2026 quote. The calculator uses $0 federal credit and state incentives only.
State Tax Credit Comparison
Idaho offers no state income tax credit. Washington offers no state income tax credit.
Net Metering Policies
Idaho: avoided-cost rate net metering active. Washington: retail rate net metering active.
Net metering is often the most economically significant solar policy because it determines how excess production is valued. Retail-rate states (where you receive full retail price for exported energy) have substantially better solar economics than avoided-cost or no-net-metering states.
Average 25-Year Savings
Idaho: $24,800 over 25 years (avg payback 10.2 yrs). Washington: $26,200 over 25 years (avg payback 9.8 yrs).
Verdict: Which State Wins on Solar?
Washington delivers stronger lifetime solar economics than Idaho due to more favorable net metering rules.
Note: state averages mask significant within-state variation. Your specific utility, roof orientation, and household electricity profile drive your actual numbers — use the calculator to model your home directly.