Attic insulation, air sealing and crawl space work across Dorchester County. We cover 4 jurisdictions here, each with its own page: the energy code that applies, the attic R-value it requires, the permit position and the building department's number. Of the county's 67,865 homes, 2% were built before 1940, and 75% of occupied homes heat with electricity.
Click a city for its full code, permit and rebate detail.
| City | Energy code | Attic R required | Permit to insulate | Building dept. |
|---|---|---|---|---|
| Unincorporated Dorchester County | 2009 IECC (state law) | R-30 | Not published | 843-832-0011 |
| Ridgeville | 2009 IECC (state law) | R-30 | Not published | 843-832-0011 |
| St. George | 2009 IECC (state law) | R-30 | Not published | 843-563-3032 |
| Summerville | 2009 IECC (state law) | R-30 | Not published | 843-851-5200 |
All 4 publish an energy code edition we could name and all 4 a required R-value we could read; a blank in this table means the jurisdiction publishes nothing, not that we guessed.
South Carolina writes one residential energy code for the whole state, and under S.C. Code 6-10-40 a town may vary it only with the state Building Codes Council's approval, so the attic figure for new work is R-30 in every one of the 4 places we cover in Dorchester County. What changes from town to town is the permit desk.
Here, Unincorporated Dorchester County and Summerville require contractors to register. The town pages carry each department's number.
The 3 places here with their own Census row hold 24,005 of Dorchester County's 67,865 homes (35%); the rest are in other municipalities or unincorporated areas.
One detail worth knowing before a job in each of them:
Dorchester County has 67,865 homes in the Census count, with a median year built of 2000. 20% were built before 1980 and 50% in 2000 or later; the single biggest decade was the 2000s, with 18,003 homes (27%). Of 63,179 occupied homes, 21% heat with utility gas and 75% with electricity.
Across the 3 places we cover here, St. George has the oldest housing (9% before 1940) and Summerville the newest (52% built in 2000 or later). Summerville is the largest, at 22,776 homes, and Summerville has the most electric heat (79%).
| Place | Homes | Before 1940 | Median built | Electric heat | Owner-occupied |
|---|---|---|---|---|---|
| Summerville | 22,776 | 3% | 2001 | 79% | 69% |
| St. George | 1,012 | 9% | 1977 | 73% | 49% |
| Ridgeville | 217 | 5% | 1977 | 77% | 77% |
Against the three-county metro on this site (378,268 homes), Dorchester County's pre-1940 share of 2% compares with 3%, and its electric-heat share of 75% with 76%. 1,067 occupied homes (2%) burn propane or other tank gas and 47 (0%) heat with wood, which matters because neither fuel comes with a gas utility's program attached. 76% of occupied homes are owner-occupied and 67% of all homes are single-family detached houses.
In Dorchester County that adds up to 12,250 homes from the 1950s to the 1970s, the usual candidates for an attic top-up; 33,744 built since 2000, where air sealing tends to matter more than extra depth.
| Built | Homes | Share | |
|---|---|---|---|
| Before 1940 | 1,072 | 2% | |
| 1940s | 452 | 1% | |
| 1950s | 1,217 | 2% | |
| 1960s | 2,917 | 4% | |
| 1970s | 8,116 | 12% | |
| 1980s | 10,677 | 16% | |
| 1990s | 9,670 | 14% | |
| 2000s | 18,003 | 27% | |
| 2010s | 12,420 | 18% | |
| 2020 or later | 3,321 | 5% |
Figures: U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates (tables B25001, B25003, B25024, B25034, B25035, B25040). Survey estimates carry margins of error, widest in the smallest places. Census table.
Homes across Dorchester County buy electricity from Dominion Energy South Carolina, Berkeley Electric Cooperative, Edisto Electric Cooperative and Coastal Electric Cooperative, and the name on the bill decides which program applies. For Dominion Energy South Carolina customers with electric heat, Home Energy Check-up Plus covers 90% of the cost of attic insulation, air sealing and duct sealing, with a ceiling of $2,880, on jobs completed by March 31, 2027 after the free Home Energy Check-up; the program's own contractor does that work, not us.
Berkeley Electric lends rather than rebates: its HomeAdvantage program lends up to $20,000 at 5%, with an energy audit first and the payments added to the electric bill. Coastal Electric members can borrow up to $10,000 on the bill; Edisto Electric lists no insulation program. Income-qualified households can apply to Palmetto Community Action Partnership (843-720-5336) for free weatherization instead. The rebate guide carries the full rules.
Nothing published settles it. None of the 4 jurisdictions we cover in Dorchester County lists insulation as permit work or as exempt, so the answer comes from a call to the building department before the job starts. Each town page gives that department's number.
R-30 for new work, in all 4 jurisdictions we cover in Dorchester County (Unincorporated Dorchester County, Ridgeville, St. George, Summerville). The Department of Energy's recommendation for an uninsulated attic in this climate zone is higher, at R49.
The Census Bureau's 2020–2024 estimates put 2% of Dorchester County's 67,865 homes before 1940 and 20% before 1980, with a median year built of 2000.
It depends on the electric utility, and Dorchester County has 4: Dominion Energy South Carolina, Berkeley Electric Cooperative, Edisto Electric Cooperative and Coastal Electric Cooperative. Dominion's Check-up Plus pays 90% of attic insulation, air sealing and duct sealing, up to $2,880, through March 31, 2027, for electrically heated homes, through its own contractor. Berkeley Electric lends rather than rebates: its HomeAdvantage program lends up to $20,000 at 5%, with an energy audit first and the payments added to the electric bill. Coastal Electric members can borrow up to $10,000 on the bill; Edisto Electric lists no insulation program. The state's federal Home Energy Rebates have not opened.
Yes, through the South Carolina Weatherization Assistance Program, which Palmetto Community Action Partnership runs for Dorchester County (843-720-5336). If the household income qualifies, the work can be free rather than discounted.
Free assessment, a measured R-value, and photos you keep either way.
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