How the state credit is presented
The South Carolina credit is 25 percent of total system cost, up to a total credit of $35,000, claimed on Form TC-38. A quote that simply subtracts 25 percent from the price is showing you the headline rather than the cash flow.
The annual limit is what matters: a taxpayer may use only $3,500 of the credit in a year, or 50 percent of their state tax liability, whichever is less, with the excess carried forward for 10 years.
Ask any installer to show the credit year by year as it would actually be received, and ask a tax advisor to sanity-check it against your own liability. If your liability is modest, the 50 percent test bites before the $3,500 one does.
Ask what the projection assumes if the credit is not fully used within the carryforward period. A household that cannot exhaust it receives less than the headline, and that is a legitimate thing for a quote to state rather than gloss.
Which metering arrangement the model assumes
Ask which utility and which arrangement the savings projection assumes. South Carolina no longer offers simple one-to-one retail net metering to new solar homes, and solar choice metering rates for Duke Energy Carolinas, Duke Energy Progress and Dominion Energy South Carolina became available for new service on or after June 1, 2021.
Because existing customers who enrolled earlier keep one-to-one compensation into 2029, older material and local word of mouth still describe that arrangement. A model built on it will overstate your return.
Under solar choice metering the value of exported power is tied to time-of-use rates, so ask for the self-consumed share of production to be shown separately from what is exported, and valued differently.
Confirm which utility serves your address first, since Santee Cooper follows its own approach and does not provide one-to-one net metering, and South Carolina is also served by electric cooperatives.
What belongs in the contract
Get equipment specified by manufacturer and model number rather than by description. Model numbers are what make a warranty enforceable later and what let you compare two quotes on the same basis rather than on adjectives.
Establish who honours each warranty and for how long. Panels, inverter and workmanship are commonly covered by three different parties on three different terms, and a company that has left the market cannot support a workmanship warranty however well drafted.
Ask what the workmanship warranty covers on roof penetrations specifically, since leaks around mounting hardware are the most common physical failure in residential solar and typically appear a few years in.
Get the production estimate into the contract along with what happens if actual production falls materially short. An estimate that appears only in a sales presentation is not a commitment, and knowing whether anyone stands behind it changes how much weight it deserves.
The state credit, and how much of it you will actually use
South Carolina offers a state income tax credit of 25 percent of the total system cost, up to a total credit of $35,000, claimed on Form TC-38. That headline is genuinely generous and it is the main reason solar still works here now that the federal residential credit has gone.
The limit that decides what it is worth to you is annual. A taxpayer may use only $3,500 of the credit in a year, or 50 percent of their state tax liability, whichever is less, and the excess for each facility can be carried forward for 10 years.
So a household with modest South Carolina tax liability may not use the whole credit within the carryforward period. That is not a reason to avoid it, but the number in a sales presentation and the number you receive can differ substantially. Ask a tax advisor how much you would realistically realise given your own liability.
The 30 percent federal Residential Clean Energy Credit under Section 25D expired for property placed in service after December 31, 2025, so a cash or loan purchase now receives no federal credit. Section 48E survives at 30 percent for third-party owners under leases and power purchase agreements, so ask any such provider what they claim and what of that value reaches you.