In Idaho, a 5.3-kW system for an average home costs about $15,787 after incentives in 2026, saves about $751 in the first year and pays back in 17.1 years.
| Item | Amount |
|---|---|
| Solar, 5.28 kW × $2.99/W | $15,787 |
| Federal credit (0%) | $0 |
| Net cost | $15,787 |
| Scenario | Net cost | Year-1 savings | Payback | 25-yr net |
|---|---|---|---|---|
| State averages (above) | $15,787 | $751 | 17.1 yr | $9,805 |
| Rates rise 5.6%/yr (2020–25 pace) | $15,787 | $751 | 14.7 yr | $20,152 |
| Rates stay flat | $15,787 | $751 | 22.2 yr | $1,896 |
| Survey price $3.6/W (LBNL) | $19,008 | $751 | 19.9 yr | $6,585 |
| Add 13.5-kWh battery | $33,351 | $1,007 | 24.4 yr | $1,016 |
| Size to 100% of use instead | $22,365 | $1,063 | 17.1 yr | $13,891 |
Verdict: at average Idaho numbers, solar is hard to justify on savings alone in 2026 — payback takes 17.1 years, leaving you $9,805 ahead after 25 years. The main reasons: cheap power (the 3rd-lowest price of 51), which caps what each kWh saves; strong sun (the 9th-best yield of 51); export credits below retail (exports earn ~50% of retail), so only the solar you use yourself earns full value. Unless your quote comes in well below the state average or your rate is higher than average, it makes more sense to cut usage first or wait for better export terms.
Net metering and exports in Idaho: Idaho Power moved from net metering to net billing (avoided-cost export credit) in Jan 2024; pre-12/20/2019 systems grandfathered to 2045.
Battery: a 13.5-kWh battery at the Idaho average of $1,301/kWh adds $17,564 and shifts about 4,435 kWh a year from low-paid exports to your own use; payback becomes 24.4 years.
Lease or PPA instead? The owner can still claim the 30% 48E credit if construction began by July 4, 2026 or the system is in service by Dec 31, 2027 — ask whether that discount is in the monthly price.
The full method, material data and tips are on the main solar payback calculator page.