South Carolina sits in a near the national average electricity rate zone — homeowners pay roughly 14.5 cents per kilowatt-hour for residential service in 2026, based on the most recent twelve-month EIA average. Annual sun-hour availability is solid at about 4.9 kWh per square meter per day, the figure NREL publishes from its National Solar Radiation Database for state-level global horizontal irradiance.
Why the rate matters
That rate matters more than installers usually admit. A high local kWh price is the single biggest accelerator of payback, because every kilowatt-hour a panel produces offsets a kilowatt-hour you would otherwise have bought. At 14.5¢/kWh, every 1,000 kWh of annual production is worth about $145 in year-one bill savings. Rates also tend to rise — the US residential rate has climbed roughly 3% per year on average over the last decade — so the gap between “solar production” and “grid purchase” widens every year you own the system.
Sun hours and what they predict
Sun-hour numbers describe how much solar energy lands on a flat horizontal surface in your state on an average day across the year. A south-facing roof at typical pitch will outperform that flat-plane number; a heavily shaded or north-facing roof will fall short. NREL’s PVWatts model, which this site uses for ZIP-level estimates, runs hourly typical-meteorological-year data through a system performance model — that’s why the same 4.9 kWh/m²/day translates to different annual output depending on tilt, azimuth, and shading at your specific address.
What incentives still apply in 2026
State-level incentives in South Carolina in 2026: 25% state tax credit up to $3,500 per year or 50% of tax liability; net billing replaced full net metering under Energy Freedom Act (Act 62) for new customers. The federal Residential Clean Energy Credit (Section 25D, the 30% federal tax credit) expired for systems placed in service after December 31, 2025, so it is not part of any new-buyer math going forward. State, utility, and property-tax incentives now carry the load.
A representative payback estimate
For a representative 7 kW residential system installed at the 2026 national average of about $3.20 per DC watt, this page estimates roughly 9,765 kWh of annual production, year-one bill savings near $1416, and a payback window of about 13.5 years. These are modeled numbers, not quotes — your roof, shading, and utility rate plan can shift them up or down by 20% or more.