Solar Panel Calculator for Boise, ID
Estimate the cost, savings and payback of solar panels in Boise, ID, using local NREL sunshine data, Idaho prices and electricity rates.
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Boise gets about 5.18 peak sun hours a day on a south-facing roof, so each kW of panels makes about 1,456 kWh a year. That ranks #51 of the 111 cities on this site. Output peaks in Jul and is lowest in Dec.
Sunshine in Boise by month
What an 8 kW system makes in Boise
| Month | Sun hours a day | Output | Bill savings |
|---|---|---|---|
| Jan | 2.11 | 440 kWh | $57 |
| Feb | 3.40 | 640 kWh | $83 |
| Mar | 4.82 | 960 kWh | $125 |
| Apr | 6.29 | 1,184 kWh | $154 |
| May | 6.95 | 1,304 kWh | $170 |
| Jun | 7.66 | 1,360 kWh | $177 |
| Jul | 8.04 | 1,440 kWh | $187 |
| Aug | 7.49 | 1,360 kWh | $177 |
| Sep | 6.14 | 1,120 kWh | $146 |
| Oct | 4.46 | 880 kWh | $115 |
| Nov | 2.74 | 544 kWh | $71 |
| Dec | 2.07 | 424 kWh | $55 |
| Year | 5.18 | 11,648 kWh | $1,517 |
Savings at 13.02¢ per kWh (Idaho average), with every kWh credited at that price.
Cost and payback by system size
At $2.95 per watt, the Idaho average, before incentives.
| System | Cost | Year 1 savings | Payback | 25-yr gain |
|---|---|---|---|---|
| 4 kW | $11,800 | $758 | 16.2 yrs | $6,062 |
| 6 kW | $17,700 | $1,137 | 16.2 yrs | $9,093 |
| 8 kW | $23,600 | $1,517 | 16.2 yrs | $12,124 |
| 10 kW | $29,500 | $1,896 | 16.2 yrs | $15,155 |
| 12 kW | $35,400 | $2,275 | 16.2 yrs | $18,186 |
How many panels you need in Boise
| Monthly use | System | 400 W panels |
|---|---|---|
| 500 kWh | 4.12 kW | 11 |
| 750 kWh | 6.18 kW | 16 |
| 1,000 kWh | 8.24 kW | 21 |
| 1,500 kWh | 12.36 kW | 31 |
| 2,000 kWh | 16.48 kW | 42 |
Covering 100% of a year's use at 1,456 kWh per kW.
Common questions
Is solar worth it in Boise?
At local averages an 8 kW system costs about $23,600 before incentives, saves about $1,517 in its first year and pays back in about 16.2 years.
How many peak sun hours does Boise get?
About 5.18 a day over the year on a south-facing roof at 20°, from 2.1 in Dec to 8.0 in Jul, according to NREL's PVWatts model.
How much does a 1 kW solar system produce in Boise?
About 1,456 kWh a year, or 121 kWh a month on average.
Is there a federal solar tax credit?
Not for homeowners who buy their system. The 30% Residential Clean Energy Credit ended for systems installed after December 31, 2025.
Sources
- NREL PVWatts V8 API (south-facing, 20° tilt, 14% losses, typical-year weather): https://developer.nlr.gov/docs/solar/pvwatts/v8/
- EnergySage, Solar panel cost by state (updated November 6, 2026): https://www.energysage.com/local-data/solar-panel-cost/
- U.S. EIA, Electric Power Monthly, Table 5.6.B (residential price, Jan–Aug 2026): https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_b