Why Idaho's incentive is smaller than it sounds
A deduction is not a credit, and the gap is significant
Idaho's state solar incentive lets you deduct 40% of your system cost from your taxable income in the first year, then 20% in each of the following three years, with each year capped at $5,000. That headline 40% number sounds substantial until you realize it only reduces the income you're taxed on, not your actual tax bill. At Idaho's 2026 flat rate of 5.3%, a full $20,000 deduction across four years is worth roughly $1,060 in real tax savings, a fraction of what a 30% credit of the same size would deliver.
No sales tax break, and property tax treatment is unclear
Idaho charges its standard 6% state sales tax on solar equipment with no solar-specific exemption, so budget for that cost the same way you would for any other home improvement purchase. Property tax treatment is murkier: some sources cite Idaho Code 63-602LL as protecting solar installations from a property tax increase, while others state plainly that Idaho offers no such exemption. Given the conflict, confirm directly with your county assessor rather than assuming either outcome, and don't confuse this with net metering, which is a separate benefit covered below. Compare against the Utah incentive estimator for a neighboring state's approach.
Net billing replaced net metering for Idaho Power customers, and rates were just cut again
As of January 2024, the Idaho Public Utilities Commission adopted real-time net billing for non-legacy Idaho Power customers, crediting exported power at a time-differentiated export credit rate below retail rather than a full one-for-one swap. Avista customers still operate under a net metering tariff with somewhat different terms. In 2025, Idaho Power sought Commission approval to cut its export credit rate further, by as much as 60% in its initial filing. Per the Commission's own order in Case No. IPC-E-25-15, the request was not denied outright: the Commission approved a smaller but still real 40% reduction, landing at roughly 15.68 cents per kWh for summer on-peak hours, 3.39 cents for summer off-peak, and 2.90 cents for all non-summer hours, effective through May 2026 and with the next update suspended until 2028. Customers who installed before December 20, 2019 remain grandfathered on the older, higher rate structure for roughly 25 years. Check the rebate stacking tool if you're weighing this alongside other incentives.
The federal credit matters even more here
With a state incentive this modest in real dollar terms, your federal eligibility carries outsized weight in Idaho's overall solar math. Run your specific situation through the federal ITC calculator to confirm what applies to you for 2026, since that number will likely dwarf whatever Idaho's state deduction contributes.
With your rebate total in hand, the combined loan and rebate timing tool shows the monthly payment on the amount you still need to borrow.