Solar panels in Nampa: what they cost and what they make
A typical Nampa home needs 19 solar panels. They would make about 11,868 kWh a year and cost $20k to $30k before incentives. At today's electricity prices they pay for themselves in about 24.7 yrs.
See panels on your own Nampa roof
Type your address. You get your roof from above, the panels that fit, a month-by-month forecast and a battery test. No phone number.
What solar costs in Nampa
At $3.00 a watt, the median price cash buyers pay nationally, a 8.0 kW system costs about $24,000. Quotes in Nampa will usually fall between $20,000 and $30,000. Complex roofs, main-panel upgrades and financing push prices up.
The 30% federal tax credit no longer applies to systems homeowners buy. This estimate includes no state or utility incentives; check with your utility before you buy.
The number that decides whether solar pays in Nampa is what your utility pays for the power you send back. Idaho Power moved to net billing: exports earn ~3–16¢ depending on season and time. Under full payback is about 15.2 yrs. Under net billing it is about 24.7 yrs, because only the ~42% of solar a typical home uses as it is made saves the full retail price.
Cash purchase, prices rising 2.5% a year, panels losing 0.5% a year, $25/kW a year for upkeep. No federal credit for homeowner-owned systems.
Every way to pay for a 8.0 kW system in Nampa
Change any number →| Way to pay | Day one | Monthly payment | Monthly net, year 1 | Ahead after 25 years |
|---|---|---|---|---|
| Pay cash Full price on install day | $24,000 | $0 | +$59 | $200 |
| Credit-union loan 8% APR, 20 years, no dealer fee | $0 | $201 | −$141 | −$24k |
| “1.99%” solar loan 1.99% APR, 25 years, 25% dealer fee | $0 | $127 | −$68 | −$14k |
| Lease $65/mo, +2.9%/yr | $0 | $65 | +$11 | $1,100 |
| Power purchase (PPA) 6.5¢/kWh, +2.9%/yr | $0 | $64 | +$12 | $3,300 |
Under net billing, the usual rule for new customers here, at 13.0¢/kWh rising 2.5% a year. The “1.99%” loan’s $6,000 dealer fee is included in its payments. Lease and PPA prices are typical offers, not quotes.
How much sunshine Nampa gets
kWh per kW, 25° southJul is the best month for solar in Nampa, and Dec the weakest: a Dec day makes 34% of a Jul day. A 6 kW system would make about 348 kWh in Dec and 1,039 kWh in Jul.
On June 21 the sun rises at 6:05 am and sets at 9:31 pm, 15 hours 26 minutes of daylight. On December 21 it is up from 8:16 am to 5:12 pm, just 8 hours 56 minutes.
Peak sun hours in Nampa, month by month
| Month | Flat ground | Panels at 37° | kWh per kW |
|---|---|---|---|
| Jan | 1.7 | 2.9 | 67 |
| Feb | 2.7 | 4.1 | 87 |
| Mar | 3.9 | 5.1 | 122 |
| Apr | 5.5 | 6.1 | 145 |
| May | 6.7 | 6.5 | 162 |
| Jun | 7.5 | 6.8 | 164 |
| Jul | 7.7 | 7.2 | 173 |
| Aug | 6.7 | 7.1 | 164 |
| Sep | 5.2 | 6.6 | 145 |
| Oct | 3.5 | 5.4 | 120 |
| Nov | 2.0 | 3.7 | 80 |
| Dec | 1.4 | 2.6 | 58 |
| Year | 4.6 | 5.3 | 1,487 |
A peak sun hour is one hour of sunlight at 1,000 W per m². Why sites disagree.
The best angle and direction for panels in Nampa
| Roof faces (6/12 pitch) | Output vs south | kWh per kW |
|---|---|---|
| South | 100% | 1,487 |
| Southeast | 95% | 1,413 |
| Southwest | 95% | 1,413 |
| East | 82% | 1,219 |
| West | 82% | 1,219 |
| North | 59% | 877 |
Face panels south and tilt them 37° for the most energy over a year. East and west roofs keep about 82% of that. A north-facing roof keeps 59%, which is rarely worth the money. Try other angles.
Where the sun goes over Nampa
The noon sun is lower in winter, which is why the best winter tilt (65°) is steeper than the best summer tilt (14°).
Nampa's homes
Nampa has 39,134 households. 70.2% own their home, and 25,921 of those owners live in single-family houses, the kind of home that usually gets rooftop solar.
The median home here was built in 2000. Most roofs this young have years of life left, which makes them good candidates for solar.
29.2% of homes heat with electricity and 68.6% with gas. If you switch to a heat pump or an electric car, plan for more panels or leave room on the roof.
Source: U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates.
If the power goes out in Nampa
Solar panels alone shut off in a blackout. Add a battery and they keep going. One Tesla Powerwall 3 (13.5 kWh) running a fridge, freezer, furnace fan, lights, Wi-Fi, TV and microwave (6.9 kWh a day):
Change the appliances, the battery and the weather in the battery calculator.
Questions people ask about solar in Nampa
How much do solar panels cost in Nampa?
A 8.0 kW system — enough for the average Idaho home — costs about $20,000 to $30,000 before incentives, based on $2.50–$3.75 per watt. The 30% federal credit no longer applies to systems homeowners buy.
How many solar panels does a house in Nampa need?
About 19 panels of 420 watts for a home using 944 kWh a month, the Idaho average. Each kilowatt of panels here makes about 1,487 kWh a year on a south-facing roof.
Is solar worth it in Nampa?
Over 25 years, solar power here costs about 10.3¢ per kWh, against 13.0¢ from the grid today. Payback is about 15.2 yrs if your utility credits exported power at the full retail rate, and 24.7 yrs if it pays about 30% of retail. Most new customers in Idaho are on the lower rate.
How many peak sun hours does Nampa get?
5.3 a day on panels tilted to 37°, and 4.6 on flat ground. The best month is Jul; the weakest is Dec.
What is the best angle for solar panels in Nampa?
37° for the most energy over a year, facing south. 65° is best in winter and 14° in summer. On a normal pitched roof, anything within 15° of 37° gives you about 95% of the maximum.
How long would a home battery last in a Nampa power outage?
A Tesla Powerwall 3 running a fridge, freezer, furnace fan, lights, Wi-Fi, TV and microwave (6.9 kWh a day) lasts about 43 hours with no sun. With 7 kW of solar to recharge it, it gets through a three-day outage even in overcast January.
Solar near Nampa
| City | Miles | kWh per kW | Sun hours |
|---|---|---|---|
| Caldwell, ID | 6 | 1,510 | 5.3 |
| Meridian, ID | 8 | 1,515 | 5.3 |
| Boise, ID | 17 | 1,519 | 5.4 |
| Twin Falls, ID | 127 | 1,558 | 5.4 |
| Pocatello, ID | 212 | 1,524 | 5.3 |
Nampa shares a weather-data neighbourhood with Boise; their sunshine numbers differ by less than our data can resolve. Housing, prices and outage figures are specific to Nampa.
Cities with the same sunshine as Nampa
These far-away cities get almost exactly as much solar energy per panel.
- Wichita, KS 1,517 kWh per kW
- Stillwater, OK 1,511 kWh per kW
- Pensacola, FL 1,509 kWh per kW
Snow: NASA records about 18 cm of snow on the ground here in an average January. Covered panels make little until it slides off, and these figures (like PVWatts') don't subtract that.
Sources: NASA POWER 2001–2020 monthly climatology (grid cell 11 km from Nampa's Census point), our PV model (within 1.6% of NLR PVWatts® on average), U.S. EIA prices and use, U.S. Census 2025 population estimates and ACS 2020–2024. Estimates for an average home, not a site survey. How we calculate.