Solar Panel Calculator for San Jose, CA
Estimate the cost, savings and payback of solar panels in San Jose, CA, using local NREL sunshine data, California prices and electricity rates.
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San Jose gets about 5.82 peak sun hours a day on a south-facing roof, so each kW of panels makes about 1,620 kWh a year. That ranks #21 of the 111 cities on this site. Output peaks in Jul and is lowest in Dec.
Sunshine in San Jose by month
What an 8 kW system makes in San Jose
| Month | Sun hours a day | Output | Bill savings |
|---|---|---|---|
| Jan | 3.35 | 672 kWh | $219 |
| Feb | 3.81 | 680 kWh | $222 |
| Mar | 5.64 | 1,080 kWh | $352 |
| Apr | 6.98 | 1,288 kWh | $420 |
| May | 7.20 | 1,344 kWh | $438 |
| Jun | 7.71 | 1,400 kWh | $456 |
| Jul | 8.02 | 1,472 kWh | $480 |
| Aug | 7.62 | 1,392 kWh | $454 |
| Sep | 6.65 | 1,176 kWh | $383 |
| Oct | 5.48 | 1,040 kWh | $339 |
| Nov | 4.11 | 776 kWh | $253 |
| Dec | 3.29 | 656 kWh | $214 |
| Year | 5.82 | 12,960 kWh | $4,222 |
Savings at 32.58¢ per kWh (California average), with every kWh credited at that price.
Cost and payback by system size
At $2.52 per watt, the California average, before incentives.
| System | Cost | Year 1 savings | Payback | 25-yr gain |
|---|---|---|---|---|
| 4 kW | $10,080 | $2,111 | 4.8 yrs | $39,651 |
| 6 kW | $15,120 | $3,167 | 4.8 yrs | $59,476 |
| 8 kW | $20,160 | $4,222 | 4.8 yrs | $79,302 |
| 10 kW | $25,200 | $5,278 | 4.8 yrs | $99,127 |
| 12 kW | $30,240 | $6,334 | 4.8 yrs | $118,953 |
How many panels you need in San Jose
| Monthly use | System | 400 W panels |
|---|---|---|
| 500 kWh | 3.70 kW | 10 |
| 750 kWh | 5.56 kW | 14 |
| 1,000 kWh | 7.41 kW | 19 |
| 1,500 kWh | 11.11 kW | 28 |
| 2,000 kWh | 14.81 kW | 38 |
Covering 100% of a year's use at 1,620 kWh per kW.
Common questions
Is solar worth it in San Jose?
At local averages an 8 kW system costs about $20,160 before incentives, saves about $4,222 in its first year and pays back in about 4.8 years.
How many peak sun hours does San Jose get?
About 5.82 a day over the year on a south-facing roof at 20°, from 3.3 in Dec to 8.0 in Jul, according to NREL's PVWatts model.
How much does a 1 kW solar system produce in San Jose?
About 1,620 kWh a year, or 135 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