How Idaho compares
Idaho ranks 46th of 51 for solar payback, fastest first. The fastest is Hawaii at 5.9 years. At U.S. average figures, payback is 12.3 years.
Two things set payback: what each kWh is worth and how many the panels make. Idaho ranks 46th for electricity price, most expensive first, at 13.73¢/kWh, and 14th for sunshine, at an estimated 1,400 kWh a year per kW of panels. Strong sun helps, but with power below the U.S. average price, each kWh the panels make saves less.
The calculator assumes power sent to the grid earns 75% of the retail price, typical of net metering. Your utility's tariff sets the real rate, and a lower credit slows payback.
Five of its six neighbors pay back faster: Montana, Nevada, Oregon, Utah and Wyoming, led by Wyoming at 13.9 years.
More for Idaho
- EV charging cost in Idaho vs gas: an EV saves $1,241 a year on fuel.
- Heat pump vs gas in Idaho: a heat pump saves $250 a year.
What these numbers assume
- A 8.0 kW system, sized to cover about 100% of a typical home's yearly use.
- $2.80 per watt installed, paid in cash, with no state or local incentives entered.
- No federal tax credit: Section 25D ended for systems placed in service after December 31, 2025.
- Half the output used in the home as it is made; the rest credited at 75% of the retail price.
- Electricity prices rising 3% a year, panels losing 0.5% of output a year, and a $2,000 inverter replacement in year 12.
Change any of them in the calculator above to match your own bills. The formulas are on the main solar payback calculator.
Sources
- Electricity price: EIA Electric Power Monthly, Table 5.6.A (July 2026 data).
- Household use: EIA 2025 retail sales divided by customers.
- Installed cost: 2026 residential marketplace averages.
- Output per kW: MeterMath estimate for a south-facing fixed roof system, rounded.
- Export credit: MeterMath assumption for typical net metering.
- Tax credit status: Public Law 119-21.