Solar Panel Cost in Idaho: $3.05/W, 22.7-Year Payback

Solar in Idaho costs about $24,400 for 8 kW at $3.05/W and pays back in roughly 22.7 years at 13.7¢/kWh with the federal credit at $0.

Updated September 2026 · Source: EIA Electric Power Monthly Table 5.6.A (July 2026 data) · next EIA update ~Oct 23

By SolarCostData Data Desk · Reviewed September 2026 · Corrections log

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Why this number

Solar panels in Idaho cost about $3.05 per watt — $24,400 for a typical 8 kW system — and pay back in roughly 22.7 years at the state’s 13.7¢/kWh average rate, with the 2026 federal credit at $0. Net billing pays exports below retail here.

Everything below uses Idaho’s real average residential electricity rate (13.7¢/kWh, EIA) and a production band of about 1,380 kWh per kW per year. Both are stated openly because they are the two inputs that decide the answer. These are estimates for sanity-checking a quote, not a quote.

Run it with your own numbers

Why Idaho’s payback lands where it does

Idaho’s rate jumped about twelve percent in a single year, from 12.28 cents per kilowatt-hour in July 2025 to 13.7 cents this July — a steep move that still leaves the state at rank 45, among the cheaper grids nationally. Even with a reasonable yield of 1,380 kilowatt-hours per installed kilowatt, that low starting rate keeps the payback long, at roughly 22.7 years. Idaho Power, the state’s largest utility with over 525,000 residential customers, prices below the state average at 11.8 cents, so its territory’s homeowners are working from an even cheaper baseline than the statewide figure and likely face a longer payback than that. Idaho compensates exports under net billing rather than full retail, so self-consumption is what actually carries the math here, meaning the fast year-over-year rate increase helps mainly through the value of power used at home rather than power sold back to the grid.

Electric utilities in Idaho

The state average hides real spreads between utilities. The largest residential utilities EIA-861 lists for Idaho, with each one’s own average bundled residential price (2024 — revenue ÷ sales, the audited annual figure, not this month’s tariff):

Your utility decides Idaho’s real number — the ZIP lookup finds it in three clicks; the 2024 annual utility averages above sit apart from the June-2026 monthly 13.7¢ state figure.

Idaho’s rate, the last 24 months

July 2025 → July 2026: 12.28¢ → 13.73¢. The rate tracker has every month against the US average.

An 8 kW system in Idaho, priced out

The $3.05/W used above comes from EnergySage marketplace quotes (August 2026). Those are quotes in a competitive online market, not signed contract prices.

Read that table with one caveat: $3.05/W is Idaho’s market average, and it is the input most likely to differ for you. A quote $0.50 per watt above or below the $3.05 used here moves the payback by roughly a year and a half in either direction.

How much sun Idaho actually gets

A kilowatt of panels in Idaho produces about 1,380 kWh a year on an unshaded, south-facing roof at a 20-degree pitch. Sites that swap Idaho’s 1,380 kWh for a single national average are how Arizona and Washington end up with identical paybacks despite a 1.6x real difference in output.

That figure is a five-point cluster around Idaho’s largest metro area, which keeps it representative of where most people actually live rather than of the state’s best site.

Two adjustments matter before you apply this to your own roof:

• Shading and orientation. The 1,380 kWh figure assumes an unobstructed south-facing array. A real Idaho roof — its own azimuth and pitch, a tree or a chimney — typically produces 10-25% less; this page models 90% of the ideal, so the 9,936 kWh/year above is already derated from 11,040. A genuinely unshaded south roof can adjust upward in the calculator.
• Year-to-year weather moves output by roughly ±5% either way.

How Idaho compares with the other 49

Idaho ranks 45th of 50 on electricity price and 41st on annual output value per kW installed — close enough that its rate is a fair proxy for its solar case, which is not true everywhere. Its immediate neighbors on price are Nebraska (13.8¢) just above and Tennessee (13.7¢) just below.

Kentucky is Idaho’s closest comparable-rate analogue — 13.8¢/kWh, roughly 1,260 kWh per kW, and a payback within about a year of this one (22.6 vs 22.7 years). If you find Idaho quotes hard to sanity-check, Kentucky numbers are broadly transferable.

Net billing: the rule that decides solar in Idaho

Idaho does not credit exports at the retail rate — this is net billing , not net metering. The program is Idaho Power Export Credit Rate, in force since 2025-09-30, and it credits surplus power at a published rate of 8.00¢/kWh — against a retail rate of 13.7¢.

15.7c summer, 2.9c non-summer. Modeled at 8.0c, a production-weighted blend assuming ~45% of annual export falls in the summer season.

Cut by 31% on 30 September 2025 — one of the largest single changes of 2025.

Because a typical Idaho home uses only about 40% of its generation as it is produced, most of what the panels make is sold at 8.0¢. That is why the payback above is 22.7 years rather than the 17.7 years the same hardware would return under full-retail net metering. Raising self-consumption — a battery (worth its own arithmetic: is a home battery worth it? ), an EV charged in daylight, daytime occupancy — is the lever that closes the gap. Whether a Idaho buyer should own a battery or take a lease/TPO deal is priced in the battery buy vs. TPO calculator .

One limit worth knowing: this reflects investor-owned, state-regulated utilities; Idaho’s municipal utilities and co-ops are exempt in most cases and set their own terms.

What is actually left in Idaho

The 30% federal credit ended for systems completed after December 31, 2025, so it is $0 here as everywhere. What remains is state, utility and local — and it varies far more than the federal rule ever did.

Residential Alternative Energy Deduction — A DEDUCTION, not a credit — 40% of cost in year one and 20% for the next three years, capped at $5,000 a year. Its cash value depends on your marginal tax rate, so it is worth materially less than a credit of the same headline percentage.

Tax exemptions

There is no property-tax exemption, so a system may raise your assessed value. Ask your assessor what it would add.

If that list looks thin, it is — the solar incentives hub shows which states still put real money on the table, and where Idaho sits among them.

Is solar worth it in Idaho at 13.7¢/kWh?

Idaho has decent sun and cheap electricity, which is a frustrating combination for solar. The panels will produce; what they produce simply is not worth much at 13.7¢/kWh.

At a horizon that long, owning the roof is not the only route to cheaper power. Community solar versus rooftop walks through the subscription alternative — no roof, no loan, and no 22.7-year wait — which is worth reading before committing capital in a market like Idaho’s.

If you want a fast gut check before running the numbers above, the should-I-go-solar screener asks the four questions that matter most in a low-rate state like Idaho.

Two numbers put that in context. At Idaho’s rate, the electricity an 8 kW system would produce is worth about $1,023 a year, so the system costs roughly 23.9 years of that output to buy outright — a simple division, before costs. The headline 22.7-year figure above is the full model: it additionally counts 2.5%/yr rate inflation, $150/yr of running costs and one inverter replacement, which is why the two differ slightly. And doing nothing is not free: 25 years of that same electricity, with rates rising at 2.5% a year, comes to about $46,591.

For a 15-year payback in Idaho — given its sunshine rather than a national average — the electricity rate would need to be about 16.6¢/kWh. Idaho is at 13.7¢, which is below it.

Sources and method

• Electricity rate: U.S. Energy Information Administration, average price by state — EIA Table 5.6.A, July 2026 data (released Sep 2026). Rate shown is Idaho’s residential average.
• Production: PVGIS v5.2 with the PVGIS-NSRDB radiation database, 1,380 kWh/kW for a five-point cluster around Idaho’s largest metro, then the 90% real-roof factor; the assumptions, the ERA5 cross-check and the attribution are on the methodology page .
• Incentives: DSIRE — Database of State Incentives for Renewables & Efficiency, NC Clean Energy Technology Center. Verify current amounts and fund status before relying on them.
• Federal credit status: IRS, Residential Clean Energy Credit . See our 2026 energy tax credit guide .
• Payback model: shared with the solar savings calculator — 2.5%/yr utility inflation, 0.5%/yr degradation, federal credit $0.

Idaho’s rate (13.7¢, EIA Table 5.6.A, July 2026 data (released Sep 2026)), export regime, production factor, installed cost and programs were last verified on 25 September 2026; Idaho’s export credit resets on its tariff cycle and incentive budgets run out mid-year, so confirm current terms before acting. Not tax or financial advice.

Frequently asked questions

How we calculated this

Worked for Idaho: 8 kW × 1,000 × $3.05/W = $24,400 gross (federal credit $0, so net before state incentives); 9,936 kWh a year × the blended kWh value at 13.7¢ retail and 8.0¢ export ≈ $1,023 year-1 saving; payback ≈ $24,400 ÷ $1,023 = 22.7 years with 2.5%/yr rate growth, 0.5%/yr degradation and one inverter replacement in the 25-year model.

Sources: U.S. Energy Information Administration (EIA) electricity rates · DSIRE incentive records · public IRS/OBBBA guidance. Figures are modeled estimates, not quotes or tax advice. See our methodology.

States with a comparable tariff picture

• Why is my electric bill so high? — Splits a bill jump into weather, rate and usage — with Idaho’s own EIA rate history built in.
• Heat pump crossover temperature — Cold-zone question: the outdoor temperature where gas beats a NEEP-listed heat pump at Idaho’s rates.
• Cost to heat a home in Idaho — Gas, propane, heating oil, heat pump and resistance per MMBtu at Idaho’s own EIA winter prices — the heating side of the same rate.
• Electricity rate tracker — Idaho’s last 24 months of EIA rates, charted against the US average.
• Find your rate by ZIP — Idaho averages hide utility gaps — look yours up from EIA-861 in three clicks.
• Net metering by state (2026 table) — Every state’s export regime with program, date and source — the rule behind Idaho’s payback.
• Solar panel cost in Kentucky — Same export regime at 13.8¢/kWh and a 22.6-year payback — the closest tariff comparison to Idaho.
• Solar panel cost in Arkansas — Same export regime at 14.3¢/kWh and a 23.0-year payback — the closest tariff comparison to Idaho.
• Solar panel cost in Utah — Same export regime at 13.1¢/kWh and a 23.8-year payback — the closest tariff comparison to Idaho.