Idaho solar in 2026 is a utility-driven market. The export math on Idaho Power (the default for southern Idaho and most of the state's solar buyers) is fundamentally different from Rocky Mountain Power (eastern) and Avista (northern) — and the difference materially changes payback. Verify your specific utility's tariff before anything else.
The headline picture:
- Idaho Power (default modeled): NET BILLING since January 1, 2024. Exports credit at the Export Credit Rate (ECR) averaging about $0.05/kWh time-of-use — and the PUC ordered a further −31% cut effective October 2025 (Sept 30, 2025 order). Self-consumption still offsets retail (about $0.10/kWh on Idaho Power), but exports earn far less.
- Rocky Mountain Power: currently 1:1 full retail for residential under 25 kW (Schedules 6 / 136). Risk flag: Schedule 136 (Feb 2025) proposed cutting export to about $0.04 + 12-month expiry; status unconfirmed.
- Avista: 1:1 full retail, BUT credits FORFEIT every March 31 — no multi-year rollover.
Plus four debunks that ID-focused solar sites get wrong:
- Federal §25D = $0 for 2026 purchases (OBBBA repeal). SmartEnergyUSA, a1solar, Today's Homeowner still cite the 30% credit as live — outdated.
- The Idaho state benefit is a DEDUCTION, not a credit (§ 63-3022C). Worth about $1,160 in actual tax savings over 4 years, not $20,000. SmartEnergyUSA wrongly calls it a "credit."
- Property tax IS exempt under Idaho Statute § 63-602LL. Multiple sources (ecowatch, SolarIQ, EnergySage, Today's Homeowner) wrongly claim NOT exempt — they are WRONG.
- Sales tax (6%) is NOT exempt on solar. About $1,400-1,700 of real added cost. Unanimous across reliable sources.
Typical solar-only payback on Idaho Power is about 15-20 years; shorter on Rocky Mountain / Avista if their 1:1 retail holds. EnergySage cites only about $7,273 of 25-year savings on a 13.45 kW Idaho Power install — weak. ID is a structurally weak-to-middle market in 2026, made worse for Idaho Power customers by the 2024 net billing transition.
What changed federally — and what's still on Idaho quotes that shouldn't be
The federal Residential Clean Energy Credit (§25D) — the 30% homeowner credit — was repealed for systems installed after December 31, 2025. For 2026 Idaho buyers, the federal credit on a purchased system is $0. The same applies to home batteries purchased outright. The §48E commercial credit (30%) still exists, but only for leased or third-party-owned systems where construction begins before July 4, 2026 — and the lessor claims it, not you. Full federal context here.
The repeal came through the One Big Beautiful Bill Act (P.L. 119-21), signed in July 2025. SmartEnergyUSA, a1solar, and Today's Homeowner all still cite the 30% federal credit as live on their Idaho solar pages — outdated. solartech confirms the repeal. If a 2026 Idaho quote includes "30% federal solar tax credit" on a purchase, ask the contractor to redo the math with $0 federal and verify with IRS.
VERIFIED 2026-06 · IRS §25D repeal under OBBBA P.L. 119-21Three utilities, three mechanisms — verify yours first
This is the single most important Idaho solar fact. The utility serving you decides your export economics, and the three IOUs operate under fundamentally different rules.
Idaho Power (southern ID, default, largest)
NET BILLING since January 1, 2024 under Idaho PUC Order Dec 29, 2023. Exports credit at the Export Credit Rate (ECR) — time-of-use, NOT retail.
- ECR averages about $0.05/kWh (Sierra Club reports $0.0596 average; range across ToU periods $0.048-0.17).
- PUC ordered a further −31% cut effective October 2025 (Sept 30, 2025 order). Current average sits in the $0.04-0.05 range.
- Real-time net billing: consumption charged at retail (about $0.10/kWh on Idaho Power residential), export credited at ECR (lower). No monthly NEG bank — credits net hourly.
- Schedule 77 is the net billing tariff.
GRANDFATHER: systems interconnected on or before December 20, 2019 keep legacy net metering at full retail through December 20, 2045. Over 14,000 ID households are now on the new net billing scheme. This calculator models the new 2026 net billing case — if you have a pre-2019 system, the old retail-credit math still applies to you until 2045.
Rocky Mountain Power (eastern ID)
Currently NET METERING — residential under 25 kW credits at FULL RETAIL 1:1 under Schedules 6 / 136. Credits roll indefinitely. Materially better than Idaho Power's net billing case.
RISK FLAG: Schedule 136 (filed Feb 2025) proposed cutting the export rate to about $0.04/kWh PLUS introducing a 12-month credit expiry, effective October 2025. The adoption status of that proposal is not confirmed as fully implemented. If adopted, Rocky Mountain economics worsen materially (closer to Idaho Power's net billing case). Verify the current Schedule 136 status with Rocky Mountain Power before signing.
Avista (northern ID)
NET METERING, NEG credited at full retail, residential systems ≤100 kW.
KEY DIFFERENCE from most NM states: NEG credits FORFEIT every March 31 — no multi-year rollover, no annual cash-out. Credits expire if not consumed within the same March-to-March cycle.
Don't oversize past annual consumption — surplus is lost at March true-up. Different mechanism from Rocky Mountain's indefinite rollover or Idaho Power's hourly net billing.
The 3 mechanisms in one picture
| Utility | Mechanism | Export rate | Credit handling |
|---|---|---|---|
| Idaho Power | Net billing | ECR about $0.05/kWh (TOU; −31% Oct 2025) | Hourly net, no bank |
| Rocky Mountain Power | Net metering | Full retail 1:1 (under 25 kW) | Rolls indefinitely (Schedule 136 risk) |
| Avista | Net metering | Full retail | Forfeits March 31 |
Idaho Power's net billing case is materially worse than Rocky Mountain's 1:1 retail (which is materially better than Avista's 1:1 with March forfeit). The utility-dependence is the single biggest variable in ID solar — bigger than $/W pricing, bigger than the federal credit, bigger than the property exemption.
VERIFIED 2026-06 · Idaho PUC Order Dec 29, 2023; Idaho PUC Order Sept 30, 2025State income tax DEDUCTION — not a credit (important nuance)
Idaho offers a DEDUCTION for residential alternative energy under Idaho § 63-3022C — and it is not a tax credit, despite what some sources claim.
The mechanics:
- 40% of solar cost deductible from taxable income in year 1.
- 20% per year for 3 more years (years 2-4).
- Maximum $5,000/year, $20,000 total deductible base.
- Filed on Form 39R.
The catch most coverage misses: this is a DEDUCTION from taxable income, NOT a direct tax credit. The actual tax saving equals:
deduction × Idaho income tax rate
At Idaho's roughly 5.8% income tax rate on a fully-used $20,000 deductible base over 4 years, that works out to about $1,160 of total tax savings — not $20,000.
SmartEnergyUSA describes this benefit as a "credit" in its Idaho solar coverage. That is wrong. It's a deduction. The difference is roughly a factor of 17 in real savings — $1,160 vs $20,000.
This calculator does not include the deduction in its modeled payback math because the actual savings depend on your specific income tax bracket and your ability to fully use the deduction across all 4 years. If you fully claim it, add about $1,160 of total tax savings over the first 4 years to the modeled numbers — a real benefit, but a modest one. (Still rare in 2026 — most states have nothing like this at all, so even a $1,160 deduction beats $0.)
Property tax — EXEMPT under § 63-602LL (sources wrongly claim otherwise)
This is the most-mis-reported fact about Idaho solar in 2026, and it goes in the buyer's favor.
Idaho Statute § 63-602LL EXEMPTS residential solar from property tax. The added home value from solar is NOT added to your property tax assessment.
Multiple solar marketing sources incorrectly claim Idaho does NOT exempt solar from property tax:
- ecowatch
- SolarIQ
- EnergySage
- Today's Homeowner
They are WRONG. The Idaho statute § 63-602LL confirms exemption for residential. (Commercial solar pays a 3.5% gross earnings tax instead of property tax — that's a different rule and doesn't affect residential rooftop.) If you see a quote that assumes solar will raise your property tax, push back; the statute is on the buyer's side.
This is a meaningful benefit. Idaho residential property rates can vary, but on a typical solar-driven home value uplift the exemption is worth real dollars over the 25-year horizon.
VERIFIED 2026-06 · Idaho Statute § 63-602LL; Idaho § 63-3022C; Form 39RSales tax — NOT EXEMPT
Idaho does not exempt residential solar from the 6% state sales tax — confirmed unanimous across reliable sources (solartech, SolarIQ, EnergySage, ussolarsupplier).
On a typical residential install this is about $1,400-1,700 of REAL added cost the installer must include. Your quote SHOULD include sales tax. If you see an Idaho solar quote that excludes the 6%, ask the installer to add it — pretending it doesn't apply misrepresents your true install cost.
Same flag pattern as Pennsylvania, Maine, Ohio, Louisiana, and North Dakota — all confirmed not-exempt.
SREC / RPS — does NOT exist in Idaho
Idaho has NO Renewable Portfolio Standard and NO SREC market. There is no SREC revenue stream available to Idaho residential solar owners.
Don't budget for SREC income — there isn't any. Any ID solar quote that includes "SREC revenue" is fictional. (This puts Idaho in the same SREC-less bucket as Indiana and North Dakota — and away from PA, MD, DE, or NJ where SREC markets are live and material.)
Battery — resilience purchase, not ROI
Idaho has NO statewide battery rebate (EnergySage). Federal storage credit $0 (§25D repealed for storage purchase).
Arbitrage gap depends on which utility serves you:
- Idaho Power: gap about $0.06/kWh (retail $0.10-0.11 vs ECR $0.05). Real but modest — "store don't export" has some value.
- Rocky Mountain Power: gap near zero (currently 1:1 retail — no haircut to arbitrage against).
- Avista: gap near zero (1:1 retail).
In all three utility cases, the $12,000 capex on a default 10 kWh battery doesn't pay back on arbitrage alone. On Idaho Power, the gap is real but Idaho's low retail makes the absolute dollar value small. On Rocky Mountain / Avista, there's essentially no arbitrage opportunity at all.
The resilience case is real for rural Idaho. Wildfire risk, winter snowstorms, multi-day outages, strong off-grid culture. If you want backup for storm season and wildfire-driven outages, a battery makes sense — for the resilience, not the ROI. The dollar math says no; the resilience math is a personal-tolerance question.
The honest payback — weak-to-middle, utility-driven
At default install pricing of about $3.17/W (range $2.70-3.65; EnergySage June 2026), typical Idaho solar-only payback on Idaho Power runs in the 15-20 year range — low retail + net billing ECR + federal $0 + 6% sales tax adds up to a long payback. EnergySage cites only about $7,273 of 25-year savings on a 13.45 kW Idaho Power install — weak.
On Rocky Mountain Power or Avista (currently 1:1 retail), the payback is shorter — closer to 10-13 years — but those gains depend on the 1:1 retail mechanism holding (Schedule 136 risk on Rocky Mountain; the March forfeit on Avista limits over-production credit).
Where Idaho fits in our verified set:
- Massachusetts (about $0.30/kWh retail + SMART): high single digits.
- New Jersey (about $0.26/kWh + SuSI): about 6.5 years.
- Connecticut (about $0.29/kWh + Netting minus SEA): about 8-10 years.
- Rhode Island (about $0.29/kWh + 80% NM + REF or REG): about 8-10 years.
- Delaware (about $0.165/kWh + 1:1 NM + rebate / SREC + no sales tax): about 9-11 years.
- New Hampshire (about $0.25/kWh + 85% NEM 2.0 locked-2041 + no sales tax): about 9.5 years.
- Indiana (about $0.16/kWh + EDG instantaneous): about 9-13.7 years.
- Ohio (about $0.16/kWh + energy-only SSO export): about 12-14 years.
- Vermont (about $0.2146/kWh + blended-rate export): about 13 years.
- Idaho — Idaho Power (about $0.10-0.11 + net billing ECR $0.05): about 15-20 years.
- Idaho — Rocky Mountain / Avista (1:1 retail if held): closer to 10-13 years.
- Louisiana (about $0.12/kWh + avoided-cost export): about 21-23 years.
- North Dakota (about $0.12/kWh + avoided-cost export + about 28% higher install): about 20-25 years.
ID is structurally weaker than IN / OH (similar retail but worse export mechanics on Idaho Power) and stronger than LA / ND (slightly higher retail, the state deduction). The Idaho Power net billing transition in 2024 + the −31% ECR cut in October 2025 are why Idaho Power solar economics keep getting worse — but the 1:1 retail utilities (Rocky Mountain, Avista) are still meaningfully better cases.
VERIFIED 2026-06 · eia.govHow to read this — Idaho's case for solar
Idaho solar in 2026 is utility-driven. Verify which utility serves you first; everything else is secondary.
- Verify your utility's tariff in writing before signing. Idaho Power net billing (ECR $0.05) vs Rocky Mountain 1:1 retail vs Avista 1:1 with March forfeit are fundamentally different cases. This is the biggest variable in ID solar.
- On Idaho Power, right-size to your load. ECR at $0.05 is weak — exports earn far less than self-consumption. Don't oversize. Match annual production to consumption.
- On Avista, don't oversize past annual consumption. March 31 forfeit means surplus is lost.
- On Rocky Mountain Power, verify Schedule 136 status before signing. If the cut is adopted, your economics worsen materially.
- Load-shift toward daylight on Idaho Power especially — every kWh shifted from grid ($0.10-0.11) to self-consumed avoids retail; exported kWh earns only ECR ($0.05).
- Reject any quote citing the federal 30% credit on a 2026 purchase. Dead.
- The Idaho state benefit is a DEDUCTION, not a credit. Worth about $1,160 over 4 years at the 5.8% ID rate, not $20,000. Add it as a modest bonus to your modeled payback.
- Property tax IS exempt under § 63-602LL — sources that say otherwise are wrong. Don't accept a quote that bakes in property tax increases from solar.
- Confirm sales tax IS in your installed quote. Idaho does NOT exempt solar from the 6% — about $1,400-1,700 of real cost.
- Don't budget for SREC revenue. Idaho has no SREC market.
- Battery for resilience, not ROI. Wildfire risk, winter outages, off-grid culture make backup a real consideration.
- Pre-Dec 20, 2019 Idaho Power systems are grandfathered to legacy retail through 2045. This calculator models the new net billing case; if you have an older system, your terms continue.
If you're on Rocky Mountain Power or Avista (currently 1:1 retail), Idaho solar makes a respectable middle-tier case in 2026 (about 10-13 years payback). If you're on Idaho Power (most ID solar buyers), expect 15-20 year payback — solar still works for self-consumption + the state deduction + the property exemption, but the ROI case is weak. If you were counting on the federal credit, on a state income tax credit (deduction is different), on 1:1 retail across all utilities, or on an SREC market — none of those apply universally.
Run your real Idaho payback →The honest picture
| Fact | Idaho (Idaho Power default) | Source |
|---|---|---|
| Federal credit | $0 (purchase) | IRS — §25D repealed under OBBBA P.L. 119-21 |
| State income tax | DEDUCTION (NOT credit) — § 63-3022C, 40% yr 1 + 20% × 3 yr, max $5,000/yr ($20,000 total), worth about $1,160 actual savings at 5.8% rate | Idaho § 63-3022C; Form 39R |
| Idaho Power mechanism | NET BILLING since Jan 1, 2024 — Export Credit Rate (ECR) | Idaho PUC Order Dec 29, 2023 |
| Idaho Power export rate | ECR about $0.05/kWh average (TOU range $0.048-0.17); PUC −31% effective Oct 2025 | Idaho PUC Order Sept 30, 2025; Sierra Club |
| Idaho Power retail | About $0.10/kWh | Idaho Power tariff |
| Idaho Power grandfather | Pre-Dec 20, 2019 systems keep legacy net metering retail through Dec 20, 2045 (14,000+ households) | Idaho PUC; Idaho Power Schedule 77 |
| Rocky Mountain Power mechanism | Net metering — 1:1 full retail under 25 kW (Schedules 6 / 136); credits roll indefinitely | Rocky Mountain Power Schedule 6 / 136 |
| Rocky Mountain risk | Schedule 136 (Feb 2025) proposed cut to about $0.04 + 12-month expiry — status unconfirmed | Idaho PUC; Rocky Mountain Power filings |
| Avista mechanism | Net metering — full retail BUT credits FORFEIT March 31 annually (no rollover) | Avista net metering tariff |
| Self-consumed | Full retail offset (utility-specific; about $0.10-0.11/kWh) | (mechanical) |
| Retail rate | About $0.11/kWh statewide ($0.115 ussolarsupplier); among LOWEST US rates | eia.gov; ussolarsupplier |
| Sales tax | NOT EXEMPT — 6% applies (about $1,400-1,700 added cost on typical install) | solartech; SolarIQ; EnergySage; ussolarsupplier |
| Property tax | EXEMPT for residential under Idaho Statute § 63-602LL (multiple sources wrongly claim otherwise — they are WRONG) | Idaho Statute § 63-602LL |
| SREC market | NONE — Idaho has no RPS, no SREC market | (no market) |
| Battery state rebate | $0 (no statewide program) | EnergySage |
| Battery federal credit | $0 (§25D repealed for storage) | IRS — §25D repealed |
| Battery arbitrage gap | About $0.06/kWh on Idaho Power; near-zero on Rocky Mountain / Avista (1:1 retail) | (mechanical) |
| $/W | About $3.17 (range $2.70-3.65) | EnergySage June 2026 |
| Typical payback — Idaho Power | About 15-20 years | This calculator; EnergySage |
| Typical payback — Rocky Mountain / Avista (1:1) | About 10-13 years | This calculator |
| 25-year savings (Idaho Power, 13.45 kW) | About $7,273 | EnergySage |
Before you commit:
- Reject any quote that includes a 30% federal credit. Repealed for 2026 purchases.
- Reject any quote that calls the Idaho state benefit a "credit." It's a DEDUCTION worth about $1,160 in actual tax savings over 4 years, not $20,000.
- Reject any quote that says property tax will go up. Idaho § 63-602LL EXEMPTS residential solar; sources that say otherwise are wrong.
- Reject any quote that includes SREC revenue. Idaho has no SREC market.
- VERIFY YOUR UTILITY'S NET METERING / NET BILLING TARIFF IN WRITING before signing. Idaho Power net billing (ECR $0.05) vs Rocky Mountain 1:1 retail vs Avista 1:1 with March forfeit are fundamentally different cases.
- On Rocky Mountain Power, verify Schedule 136 status specifically — the Feb 2025 proposal to cut export to about $0.04 + 12-month expiry has unconfirmed adoption status.
- Confirm sales tax IS in your installed quote. Idaho does NOT exempt — about $1,400-1,700 of real cost.
- Don't oversize. Idaho Power ECR at $0.05 punishes export; Avista forfeits surplus at March 31; even Rocky Mountain's current 1:1 may shift if Schedule 136 adopts. Right-size to annual consumption.
- Load-shift toward daylight on Idaho Power. Self-consumption at about $0.11 vs export at $0.05 is a 2x swing.
- The state deduction adds about $1,160 of tax savings over 4 years. File Form 39R. Modest but real — most states offer nothing comparable in 2026.
- Battery is a resilience purchase, not an ROI purchase — wildfire, winter outages, off-grid culture are the real case.
- Pre-Dec 20, 2019 Idaho Power systems are grandfathered through 2045 — if you already have solar, your old NM terms continue.
Estimates only — Idaho Power ECR updates annually (and the PUC has cut it twice in 2024-2025), Rocky Mountain Schedule 136 adoption status is unconfirmed as of mid-2026, state deduction savings depend on individual income tax bracket and ability to fully use the deduction across 4 years. Verify with the Idaho Public Utilities Commission, your specific utility (Idaho Power, Rocky Mountain Power, Avista, or your co-op / municipal), the Idaho State Tax Commission for property tax and deduction details, and solartech for current incentive listings. This is not financial advice.