Solar panels in Boise, ID
Roofs in Boise get about 1,594 hours of usable sunlight a year — more than 63% of the cities we've measured. Here's what that means in cost, savings and payback, using real rooftop data rather than a national average.
Check your specific roof in Boise → City averages are a starting point; your own roof's size, pitch and shading change the answer a lot.
What a typical Boise solar system costs
A 20-panel system (8 kW) is about right for an average Boise home using 10,800 kWh a year. It would produce roughly 10,839 kWh annually and offset 100% of that usage.
| System | Size | kWh/yr | Net cost | Saves/yr | Payback |
|---|---|---|---|---|---|
| 8 panels | 3.2 kW | 4,336 | $6,384 | $486 | 13.1 yrs |
| 12 panels | 4.8 kW | 6,504 | $9,576 | $728 | 13.1 yrs |
| 16 panels | 6.4 kW | 8,671 | $12,768 | $971 | 13.1 yrs |
| 20 panels | 8 kW | 10,839 | $15,960 | $1,211 | 13.2 yrs |
| 26 panels | 10.4 kW | 14,091 | $20,748 | $1,302 | 15.9 yrs |
How we worked this out for Boise
Every number on this page comes from these seven steps. Nothing is a national average — the sunlight figure is measured from Boise rooftops.
| # | Step | Result |
|---|---|---|
| 1 | What one panel makes here 400W ÷ 1000 × 1,594 sun hrs × 0.85 system losses |
542 kWh/yr |
| 2 | Panels needed to cover typical usage 10,800 kWh ÷ 542 kWh per panel |
20 panels |
| 3 | System size 20 panels × 400W |
8.00 kW |
| 4 | Annual production 8.00 kW × 1,594 hrs × 0.85 |
10,839 kWh/yr |
| 5 | Installed cost 8,000 W × $2.85 per watt, then −30% federal credit |
$15,960 |
| 6 | Annual saving 3,780 kWh used as generated × 11.2¢ + 7,059 kWh exported × 11.2¢ |
$1,211/yr |
| 7 | Payback $15,960 ÷ $1,211 per year |
13.2 years |
Step 6 matters more than it looks. Only 35% of what a system this size produces in Boise is used the moment it is generated; the other 7,059 kWh is exported and credited one-for-one under net metering. Because exports here are credited at or near retail, that split changes the payback very little — 13.1 years against the 13.2 we show. In places where exports pay a fraction of retail the same split moves payback by years, which is why we model it explicitly rather than assuming.
Assumptions: 400W panels, 15% system losses (inverter, wiring, heat, soiling), $2.85/W installed, 10,800 kWh typical annual household use, 11.2¢/kWh electricity. Change any of those and every figure above moves — which is exactly why a single national "solar costs X" number is misleading.
Notice that payback barely improves as systems get bigger, and eventually gets worse. That's because you can only save money on electricity you were going to buy anyway. Once a system covers your usage, extra panels mostly generate exports at a much lower rate.
Why Boise gets 1,594 sun hours
That figure comes from Google's analysis of real rooftops across Boise — it already accounts for shading from trees, chimneys and neighbouring buildings, which is why it's lower than the raw "hours of daylight" figures you'll see elsewhere. An unusually open, unshaded roof in Boise reaches about 1,764 hours, roughly 11% better than typical.
The numbers behind this page
| Typical usable sunlight | 1,594 hrs/yr |
|---|---|
| Unshaded roof | 1,764 hrs/yr |
| Electricity rate (Idaho avg) | 11.2¢/kWh |
| Installed cost assumed | $2.85/W |
| Panel size assumed | 400 W |
| Federal tax credit | 30% |
| Typical household usage | 10,800 kWh/yr |
| Power used as generated | 35% |
| Paid for exported power | full retail (net metering) |
| Rooftops sampled here | 9 |
| Google imagery from | 2023 |
When Boise actually produces
Annual totals hide the thing that catches people out: 38% of Boise's yearly sunlight arrives in May–July, and just 12% across November–January.
| Month | Sun hrs | Share of year |
|---|---|---|
| Jan | 64 | |
| Feb | 91 | |
| Mar | 127 | |
| Apr | 166 | |
| May | 194 | |
| Jun | 206 | |
| Jul | 200 | |
| Aug | 177 | |
| Sep | 141 | |
| Oct | 101 | |
| Nov | 70 | |
| Dec | 57 |
Boise produces about 3.6× as much in Jun as in Dec — a normal mid-latitude swing. Expect real winter shortfall and summer surplus rather than steady year-round output.
The annual total is measured from Google's rooftop imagery. Its split across months is calculated from solar geometry at Boise's latitude, not separately measured, so treat the monthly figures as the shape of a typical year rather than a forecast.
How Boise compares to the other 788 cities
| Measure | Boise | Rank of 788 |
|---|---|---|
| Usable sunlight | 1,594 hrs | 287th |
| Sunlight lost to shade | 10% | 84th most |
| Median roof size | 261 m² | 192nd largest |
| Electricity rate | 11.2¢ | 743rd highest |
| Payback | 13.2 yrs | 651st fastest |
| Grid carbon | 696 kg/MWh | 210th dirtiest |
What actually stands out about Boise:
- Shading is a real problem here. Boise loses 10% of its potential sunlight to trees, chimneys and neighbouring buildings — the 84th-worst of the 788 cities measured. Panel placement matters more here than in most places, and a roof survey is worth more than a phone quote.
- Plenty of roof to work with. Typical roofs here fit around 90 panels — roughly 4× what an average home needs. Roof size will not be what limits your system in Boise.
- Cheap electricity is the headwind. Idaho power costs about 11.2¢/kWh. Low rates are good news generally, but they lengthen solar payback — there is simply less bill to displace.
Cities with almost the same sunlight
These are the closest matches to Boise's 1,594 usable sun hours from other states and provinces. Same sunlight, different electricity prices — which is usually what decides whether solar is worth it.
| City | Sun hrs | Rate | Payback |
|---|---|---|---|
| Albany, GA | 1,594 | 14.1¢ | 10.5 yrs |
| Texarkana, AR | 1,595 | 12.4¢ | 11.9 yrs |
| Butte, MT | 1,595 | 12.1¢ | 12.2 yrs |
| Longview, TX | 1,595 | 15.1¢ | 9.8 yrs |
Nearby cities
See all of Idaho → statewide sunlight, rates, incentives and every city we've measured.
Boise solar questions
How many solar panels do I need in Boise?
About 20 panels for an average home using 10,800 kWh a year. Boise roofs get 1,594 usable sun hours, so each 400W panel produces roughly 542 kWh annually. A typical Boise roof fits about 90 panels, so roof space is unlikely to be your limit.
Is solar worth it in Boise?
At 11.2¢/kWh and 1,594 sun hours, a typical system pays for itself in about 13.2 years and returns roughly $14,307 over a 25-year panel life. That is slower than average, so compare several quotes before committing. Exported power earns full retail credit here.
How much do solar panels cost in Boise?
A 8 kW system costs about $22,800 before incentives and $15,960 after the 30% federal tax credit. That works out near $2.85 per watt installed. Roof pitch, shading, electrical panel upgrades and equipment choice move the price most, which is why quotes for the same house can differ by thousands.
Worth reading before you buy
Estimates only, generated 2026-08-22 from Google Solar API rooftop samples and average Idaho electricity rates. Not a quote and not financial advice. Your roof, usage, utility plan and local incentives will change these numbers — get real quotes before buying.