Solar Panel Calculator for San Francisco, CA
Estimate the cost, savings and payback of solar panels in San Francisco, CA, using local NREL sunshine data, California prices and electricity rates.
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San Francisco gets about 5.45 peak sun hours a day on a south-facing roof, so each kW of panels makes about 1,530 kWh a year. That ranks #37 of the 111 cities on this site. Output peaks in Jun and is lowest in Dec.
Sunshine in San Francisco by month
What an 8 kW system makes in San Francisco
| Month | Sun hours a day | Output | Bill savings |
|---|---|---|---|
| Jan | 3.15 | 632 kWh | $206 |
| Feb | 4.45 | 784 kWh | $255 |
| Mar | 5.06 | 984 kWh | $321 |
| Apr | 6.86 | 1,272 kWh | $414 |
| May | 7.04 | 1,336 kWh | $435 |
| Jun | 7.25 | 1,328 kWh | $433 |
| Jul | 6.69 | 1,248 kWh | $407 |
| Aug | 6.25 | 1,160 kWh | $378 |
| Sep | 6.29 | 1,128 kWh | $368 |
| Oct | 5.06 | 968 kWh | $315 |
| Nov | 4.12 | 776 kWh | $253 |
| Dec | 3.13 | 624 kWh | $203 |
| Year | 5.45 | 12,240 kWh | $3,988 |
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 | $1,994 | 5.1 yrs | $36,888 |
| 6 kW | $15,120 | $2,991 | 5.1 yrs | $55,332 |
| 8 kW | $20,160 | $3,988 | 5.1 yrs | $73,776 |
| 10 kW | $25,200 | $4,985 | 5.1 yrs | $92,220 |
| 12 kW | $30,240 | $5,982 | 5.1 yrs | $110,664 |
How many panels you need in San Francisco
| Monthly use | System | 400 W panels |
|---|---|---|
| 500 kWh | 3.92 kW | 10 |
| 750 kWh | 5.88 kW | 15 |
| 1,000 kWh | 7.84 kW | 20 |
| 1,500 kWh | 11.76 kW | 30 |
| 2,000 kWh | 15.69 kW | 40 |
Covering 100% of a year's use at 1,530 kWh per kW.
Common questions
Is solar worth it in San Francisco?
At local averages an 8 kW system costs about $20,160 before incentives, saves about $3,988 in its first year and pays back in about 5.1 years.
How many peak sun hours does San Francisco get?
About 5.45 a day over the year on a south-facing roof at 20°, from 3.1 in Dec to 7.2 in Jun, according to NREL's PVWatts model.
How much does a 1 kW solar system produce in San Francisco?
About 1,530 kWh a year, or 128 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