Solar Panel Calculator for Charleston, SC
Estimate the cost, savings and payback of solar panels in Charleston, SC, using local NREL sunshine data, South Carolina prices and electricity rates.
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Charleston gets about 5.26 peak sun hours a day on a south-facing roof, so each kW of panels makes about 1,431 kWh a year. That ranks #46 of the 111 cities on this site. Output peaks in May and is lowest in Dec.
Sunshine in Charleston by month
What an 8 kW system makes in Charleston
| Month | Sun hours a day | Output | Bill savings |
|---|---|---|---|
| Jan | 4.04 | 800 kWh | $127 |
| Feb | 4.35 | 768 kWh | $122 |
| Mar | 5.29 | 1,000 kWh | $159 |
| Apr | 6.04 | 1,080 kWh | $172 |
| May | 6.52 | 1,176 kWh | $187 |
| Jun | 6.33 | 1,088 kWh | $173 |
| Jul | 6.20 | 1,096 kWh | $174 |
| Aug | 5.88 | 1,048 kWh | $167 |
| Sep | 5.32 | 928 kWh | $148 |
| Oct | 5.09 | 952 kWh | $151 |
| Nov | 4.45 | 824 kWh | $131 |
| Dec | 3.58 | 704 kWh | $112 |
| Year | 5.26 | 11,448 kWh | $1,820 |
Savings at 15.90¢ per kWh (South Carolina average), with every kWh credited at that price.
Cost and payback by system size
At $2.57 per watt, the South Carolina average, before incentives.
| System | Cost | Year 1 savings | Payback | 25-yr gain |
|---|---|---|---|---|
| 4 kW | $10,280 | $910 | 11.6 yrs | $11,159 |
| 6 kW | $15,420 | $1,365 | 11.6 yrs | $16,738 |
| 8 kW | $20,560 | $1,820 | 11.6 yrs | $22,317 |
| 10 kW | $25,700 | $2,275 | 11.6 yrs | $27,897 |
| 12 kW | $30,840 | $2,730 | 11.6 yrs | $33,476 |
How many panels you need in Charleston
| Monthly use | System | 400 W panels |
|---|---|---|
| 500 kWh | 4.19 kW | 11 |
| 750 kWh | 6.29 kW | 16 |
| 1,000 kWh | 8.39 kW | 21 |
| 1,500 kWh | 12.58 kW | 32 |
| 2,000 kWh | 16.77 kW | 42 |
Covering 100% of a year's use at 1,431 kWh per kW.
Common questions
Is solar worth it in Charleston?
At local averages an 8 kW system costs about $20,560 before incentives, saves about $1,820 in its first year and pays back in about 11.6 years.
How many peak sun hours does Charleston get?
About 5.26 a day over the year on a south-facing roof at 20°, from 3.6 in Dec to 6.5 in May, according to NREL's PVWatts model.
How much does a 1 kW solar system produce in Charleston?
About 1,431 kWh a year, or 119 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