Idaho Solar Calculator & Net Billing Guide
Idaho has no statewide net metering law. Idaho Power, Avista, and Rocky Mountain Power each run separate tariffs with meaningfully different export credit structures — and at least one is actively changing. Here's what Idaho homeowners actually need to know in 2026.
Federal Tax Credit Expired: The 30% federal residential solar tax credit (Section 25D) expired December 31, 2025 under the One Big Beautiful Bill Act. It is not available for systems installed in 2026 or later. Any guide still citing this credit for 2026 installations is outdated.
Idaho's Three-Way Utility Split
Unlike states with a single net metering law, Idaho homeowners must know which investor-owned utility serves their address — the export credit rules are genuinely different between Idaho Power, Avista, and Rocky Mountain Power. There is no "Idaho net metering" to describe generically.
Idaho Power — Switched to Net Billing (January 2024)
Southern and central Idaho, including Boise, Twin Falls, Nampa, Meridian
Idaho Power transitioned from traditional net metering to net billing in January 2024. New solar customers receive export credits at the avoided-cost rate rather than the full retail rate. The Sierra Club has estimated this change reduces the value of exported solar power by roughly 32% compared to the old net metering structure.
Under net billing, the financial case for rooftop solar shifts strongly toward maximizing self-consumption — using as much of your solar production directly rather than exporting it. Pairing with battery storage or shifting daytime loads (dishwashers, EV charging, laundry) to solar-peak hours improves your return.
Grandfathered customers: Homeowners who installed or purchased their system by December 20, 2019 remain on the original net metering structure until December 20, 2045. If you qualify, confirm your grandfathered status directly with Idaho Power.
Confirm Idaho Power's current avoided-cost rate at idahopower.com or by calling Idaho Power directly.
Rocky Mountain Power — Rate Change Pending or Approved (Verify Now)
Eastern Idaho, including Pocatello, Idaho Falls, Blackfoot
Rocky Mountain Power moved to net billing under Schedule 136 in November 2020. Residential systems under 25kW continued receiving the full retail rate (roughly 9–10¢/kWh) for exported power under the continued structure.
This is actively changing — confirm before relying on any figure. In February 2025, Rocky Mountain Power filed Idaho PUC Case No. PAC-E-25-02, proposing to replace the retail-rate export credit with a time-differentiated rate of roughly 4¢/kWh (updated annually) — targeting an October 1, 2025 effective date, pending IPUC approval. The utility's own estimate was that this change would raise the average monthly bill for solar customers from about $52 to about $89, roughly a 72% increase.
By the time you read this in 2026, this proposal may already be approved and in effect. Do not assume the old retail-rate structure still applies. Confirm the current approved export credit rate directly with Rocky Mountain Power or the IPUC at puc.idaho.gov.
Avista — Retail-Rate Credits, But Annual Forfeiture
Northern Idaho, including Coeur d'Alene, Sandpoint, Moscow, Lewiston
Avista credits net excess generation at the retail rate for systems up to 100kW — a meaningful advantage compared to Idaho Power's avoided-cost net billing structure.
Critical caveat: Unused credits are forfeited back to Avista at the end of each year. There is no rollover to the next billing year and no cash payout. This means if your system consistently overproduces relative to your annual consumption, those surplus credits disappear at year-end with no financial benefit. Right-sizing your system to match your annual load is especially important for Avista customers.
Verify current Avista tariff terms at myavista.com or with the IPUC.
Idaho's State Solar Incentive: A Deduction, Not a Credit
Idaho Form 39R — Residential Alternative Energy Deduction
This is a state income tax deduction — not a credit. The distinction matters significantly.
What a Credit Does
Reduces your tax bill dollar-for-dollar. A $3,000 credit cuts your taxes by exactly $3,000 regardless of your income.
What a Deduction Does
Reduces your taxable income. The actual tax savings depend on your marginal state rate — at Idaho's 5.8% top rate, a $5,000 deduction saves at most $290 in state taxes that year.
Idaho's 4-Year Deduction Schedule:
| Year | Deduction % | Cap |
|---|---|---|
| Year 1 (installation) | 40% of cost | $5,000 max |
| Year 2 | 20% of cost | $5,000 max |
| Year 3 | 20% of cost | $5,000 max |
| Year 4 | 20% of cost | $5,000 max |
| Total | 100% of cost | $20,000 total max |
At Idaho's top marginal rate of 5.8%, the maximum total benefit from fully utilizing the $20,000 cap is roughly $1,160 in state tax savings over 4 years — real money, but far less than what a credit of the same face value would provide. File with Idaho Form 39R each year you claim the deduction. Consult a tax professional for your specific situation.
Idaho Solar Context at a Glance
~10–12¢/kWh
Among lowest in the U.S.
4.8–5.1/day
Boise often cited slightly higher
Longer than avg.
Low rates extend payback vs. high-cost states
Tax Deduction
100% of cost over 4 years, capped at $20k total
Honest Framing: Low Rates Mean Longer Payback
Idaho consistently ranks among the states with the lowest average residential electricity rates — roughly 10–12¢/kWh, well below the national average of around 16–17¢/kWh. This is generally good news for Idaho households' monthly bills, but it has a direct effect on solar economics: every kilowatt-hour your system produces saves you less money than it would in Hawaii, California, or New England.
Combine this with Idaho Power's and Rocky Mountain Power's reduced export credit structures (avoided cost rather than full retail), and the financial case for rooftop solar in Idaho is more nuanced than in high-electricity-cost states. Idaho homeowners should not expect the short payback periods often cited for other states.
This does not mean solar is a bad investment in Idaho — strong sun resources (4.8–5.1 peak sun hours/day), the state tax deduction, and the potential for future rate increases all factor in. But get a detailed, site-specific analysis from a local installer that uses your utility's current export credit rate and your actual consumption data rather than national averages.
Additional Idaho Solar Benefits
Property Tax Exemption
Idaho exempts residential solar systems from property tax assessment under Idaho Code § 63-602T. The added home value from a solar installation should not increase your property tax bill. Confirm with your county assessor.
Sales Tax Exemption
Solar energy systems are exempt from Idaho sales tax under Idaho Code § 63-3622R. This saves the standard 6% Idaho sales tax on equipment costs at point of purchase. Ask your installer to confirm exemption treatment on the invoice.
No State Solar Tax Credit
Idaho does not offer a state solar income tax credit. The state incentive is the tax deduction described above (Form 39R), not a credit. These are different mechanisms with different financial impacts.
Federal Tax Credit Expired (Section 25D)
The 30% federal residential solar tax credit (Section 25D) expired December 31, 2025. It does not apply to systems installed in 2026 or later. Any guide or installer quote referencing this credit for a 2026 installation is citing outdated law.
Estimate Your Idaho Solar Savings
Enter your monthly electric bill to get a personalized estimate. For the most accurate analysis, confirm your utility's current export credit rate before finalizing any decision.
Estimate Your Solar Savings
Find out how much you can save based on your location and current energy usage.
Frequently Asked Questions — Idaho Solar
Frequently Asked Questions
Everything you need to know about solar incentives, costs, and savings.
Idaho Solar Resources
DISCLAIMER: All estimates are approximations based on regional averages. Actual savings vary by location, roof orientation, utility provider, and installer. This calculator does not guarantee specific savings.