Ask what solar costs in Idaho and the answer starts with a question back: which utility bills your house? Idaho runs two different solar regimes at once. Idaho Power, serving about 63% of the state’s homes, moved to real-time net billing in January 2024, crediting exports at avoided-cost rates the moment they flow out. Avista, with about 15%, still nets kilowatt-hours at retail the classic way. Same panels, same sun, two different paybacks. With installs at $3.09 per watt against 12.52¢ power, the margins here are thin enough that the rulebook difference is the whole story.
Which Rulebook Covers Your Address
Utility | Share of Idaho Homes | How Your Solar Is Valued |
|---|---|---|
Idaho Power | ~63% | Real-time net billing since January 1, 2024: self-used power offsets retail; exports credited at avoided-cost rates the instant they flow |
Avista | ~15% | Retail kilowatt-hour netting retained: the classic 1-to-1 arrangement |
Rocky Mountain Power | ~9% | Net billing at avoided-cost rates |
Co-ops (Kootenai and others) | ~13% | Each sets its own terms; confirm before modeling anything |
The export rates at the net-billing utilities change by order and season, and current filings run well below retail; get your utility’s current schedule in writing rather than trusting any fixed number in a sales proposal, including one on this page. What does not change: under real-time billing, power you use as it is produced is worth the retail rate your utility charges, modeled here at the 12.52¢ statewide average, and power you export is worth meaningfully less.
The Sticker: Pricey Installs, Cheap Power
Idaho’s benchmark installed price is $3.09 per watt (as of March 1, 2026), rank 41 nationally, while its electricity is among the cheapest at 12.52¢, rank 47. That is the awkward pairing: above-average hardware costs earning below-average savings per kilowatt-hour. The sun helps, 5.35 peak hours and a solid 1,506 kWh per kW per year in Boise-class light, and the typical 7.52 kW system runs about $23,243 gross, producing around 11,325 kWh annually against the average home’s 11,330 kWh of use.
The benchmark across sizes, gross before incentives, with the average month of production each delivers, which is the number real-time billing makes you care about:
System size | Gross cost at $3.09/W | Average month of output (kWh) |
|---|---|---|
5 kW | $15,450 | About 628 |
6 kW | $18,540 | About 753 |
7.52 kW, the typical Idaho system | $23,243 | About 944 |
9 kW | $27,810 | About 1,130 |
10 kW | $30,900 | About 1,255 |
Find out which rulebook your address is under
Two Paybacks for One State
For an Avista household with classic netting, production offsets retail nearly in full: about $1,418 a year at the 12.52¢ statewide average, modeling to a 16-to-17-year payback, long by national standards because the power being replaced is so cheap. For an Idaho Power household under real-time billing, that same figure is the ceiling, not the estimate: every exported kilowatt-hour earns the lower avoided rate, so the realistic number stretches beyond it unless daytime self-use is high. Idaho’s 3.1% annual rate growth chips away at both numbers slowly. This is a state where solar is a long-horizon infrastructure decision, not a quick win, and where load-shifting and right-sizing matter more for Idaho Power customers than any equipment choice.
Both figures run on the statewide average, which is ranking context rather than a filed rate. Avista and Idaho Power each file their own residential rates, so rerun the math with the rate on your own bill.
Buying Well in a Thin-Margin State
Hold bids to the $3.09 benchmark and make installers justify every dime above it, because thin savings margins amplify overpayment. Size at or below annual usage; overproduction in a net-billing territory is hardware bought to sell cheap power. Ask which utility’s current export schedule the proposal models, and reject any that answers with a generic number. And check the third-party fine print: Idaho’s PPA legality is unclear rather than established, so lease-style offers deserve a lawyer’s read before signature, especially with the federal residential credit at $0 for host-owned systems whose installation is completed after December 31, 2025.
When Idaho Solar Is the Wrong Spend
- Idaho Power homes empty all day. Real-time billing with low self-use is the worst combination in the state; fix the usage pattern or reconsider.
- Anyone buying on a fast-payback pitch. Idaho’s floor is 16 years; a proposal showing 8 is modeling a different state.
- Short-stay owners. The math needs a long runway or a sale that prices the system in.
- Co-op members who have not asked. A quarter of the state is outside the big-three rulebooks entirely; your co-op’s terms could be better or worse, and guessing is free until it costs you $23,243.
Idaho Solar Cost FAQs
About $3.09 per watt installed, rank 41 nationally, as of March 1, 2026. The typical 7.52 kW system runs about $23,243 before incentives.
It depends on your utility. Avista still nets kilowatt-hours at retail the classic way, while Idaho Power moved to real-time net billing in January 2024 and Rocky Mountain Power also credits exports at avoided-cost rates. Co-ops set their own terms.
Around 16 to 17 years for an Avista household with retail netting, and longer for Idaho Power customers unless daytime self-use is high, because exports there earn avoided-cost rates. Cheap 12.52¢ power is the main reason paybacks run long.
Idaho Power moved new customers to real-time net billing effective January 1, 2024 under commission-approved changes, crediting exports at avoided-cost rates as they flow rather than netting kilowatt-hours across the billing period. Current export schedules are filed with the commission and change over time, so confirm the current figure directly.
For long-horizon owners with good roofs, high daytime usage, or Avista service, the math works slowly and steadily. For quick-payback expectations, Idaho is the wrong state: cheap grid power keeps even the best case around 16 years.
The first fact to establish is which rulebook your meter lives under. Enter your ZIP code and we will start exactly there.
Get bids modeled for your utility, not the state
Methodology: Cost figures in this guide use the EcoGen Solar Cost Index for Idaho, $3.09 per watt as of March 1, 2026, with payback modeled with no federal residential credit for host-owned systems, exports below retail at net-billing utilities, rate escalation at the state 5-year average of 3.1%, 0.5% annual panel degradation, and a 25-year horizon. Per-utility export rates change by commission order and are stated as structure only.
References & Research Sources
EcoGen America reviewed Idaho Public Utilities Commission billing orders, Avista and Idaho Power rate schedules, federal electricity price and utility datasets, Census home-value data, federal tax guidance, and state PPA-legality research for this Idaho solar cost guide. Sources were accessed between June 10 and August 15, 2026, unless another date is listed below.
- Idaho Public Utilities Commission (IPUC). Orders 36048 and 36785. Idaho Power’s move to real-time net billing effective January 1, 2024, and the export credit rate effective October 1, 2025 with annual updates paused until an April 1, 2028 filing. Accessed June 11, 2026.
- Avista Utilities. Schedule 63: Residential Net Metering. Retail kilowatt-hour netting with credits surrendered at year-end. Accessed June 11, 2026.
- U.S. Energy Information Administration (EIA). Electric Power Monthly, Table 5.6.A. Average residential electricity prices by state, March 2026 edition. Accessed June 10, 2026.
- U.S. Energy Information Administration (EIA). Form EIA-861: Annual Electric Power Industry Report, 2024. Residential customer counts for Idaho Power, Avista, PacifiCorp, and Kootenai Electric. Accessed June 10, 2026.
- U.S. Census Bureau. American Community Survey, 2024. Median home value data used for cost-to-value context. Accessed June 11, 2026.
- Internal Revenue Service (IRS). One, Big, Beautiful Bill Provisions. Guidance on Public Law 119-21, including termination of the Section 25D residential credit for systems whose installation is completed after December 31, 2025. Accessed August 15, 2026.
- Database of State Incentives for Renewables & Efficiency (DSIRE). Third-Party Solar PV Power Purchase Agreement Policies, May 2026. State-by-state PPA legality map. Published May 2026. Accessed August 15, 2026.
