What a grid-tied array does when the power goes out
A grid-tied system without storage disconnects during an outage. People reasonably assume that panels plus sunshine equals electricity, and learning otherwise during a storm week is the expensive way to find out.
If keeping part of the house running matters, ask any installer to be specific rather than general. Which circuits stay live, for how long at a realistic load, and does the battery recharge from the array while the grid is down. Those differences compound over several days.
Be concrete about the load you want to carry. A system keeping a fridge, some lighting and a few outlets going for days is a very different proposition from one attempting to run air conditioning in a Lowcountry summer, and that conversation belongs before the contract.
Ask how a battery sized for outage cover compares with one sized for everyday bill savings. They are frequently not the same system, and knowing which you are being quoted is essential before comparing prices between installers.
Where storage does help the bill here
Unlike a state with one-to-one retail crediting, South Carolina gives storage a genuine bill case for new customers. The value of exported power under solar choice metering is tied to time-of-use rates, so electricity is not worth the same at every hour.
A battery can hold production for the hours when electricity is expensive rather than exporting it when it is cheap. That is a calculable return rather than a matter of taste, and it is worth asking for as arithmetic.
Ask how many kilowatt hours per year would move through the battery, what the value difference is between exporting them and using them later, what the storage costs, and over what period the difference repays it.
Then keep the outage benefit as a separate line. It is real and it may be the main reason you buy, but it does not belong blended into a savings figure, because only one of the two can honestly go in a spreadsheet.
Coastal hardware, siting and your insurer
Ask what the mounting is specified to withstand, how attachments are detailed, and whether the installer has done coastal work in the Lowcountry before. Salt air and wind-driven rain are harder on a roof and on hardware than inland conditions.
Ask where the inverter and any battery would be sited and how that placement relates to your property's exposure. Equipment location is a design decision made once, so raise it deliberately rather than leaving it to convenience.
Talk to your home insurer before installation. Ask whether a rooftop array and any battery are covered under your policy, whether either changes your premium or your deductible, and what documentation they want on file afterwards. Wind and hurricane deductibles are frequently a percentage of insured value rather than a flat amount.
Check the roof covering at the same time. Panels outlast most coverings, and coastal exposure ages one faster than the calendar suggests, so ask for a condition assessment rather than an age estimate.
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.