Georgetown County, SC Insulation Payback
Georgetown County attic insulation, by the numbers
DOE classifies Georgetown County as climate zone 3, hot-humid — summers that stay hot and humid while winters barely register on the energy bill. Its recommended attic R-value for bare joists is R-49. For an attic around 1,000 square feet, closing the gap from R-2 to R-49 costs around $2,820 and saves an estimated $939 a year — payback in roughly 3 years. Topping up the attic pays for itself here.
Where the savings come from
Split it out and it's roughly $582 a year on the heating side, $358 on cooling. By estimated insulation savings, Georgetown County lands in the 12th percentile nationally. Zone 3 alone covers 690 counties in this dataset, and Georgetown County comes in 598th by savings. South Carolina averages $1,016/year across the counties tracked here; Georgetown County comes in 8% lower.
The climate data behind this
The heating and cooling degree days behind this estimate — 2,192 HDD and 2,244 CDD (base 65°F, 1991-2020 normals) — come from GEORGETOWN CO AP, SC US, the nearest NOAA station with published normals, 7.1 miles from Georgetown County's center. By total degree days, Georgetown County sits at the 9th percentile nationally. One local detail the R-value alone won't tell you: Georgetown County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
If the attic isn't bare
If Georgetown County's attic already has 3-4 inches of old insulation (about R-11) rather than bare joists, the recommended target drops to R-38. That smaller top-up costs around $1,620 and saves an estimated $126/year — payback about 12.8 years. Call this borderline rather than a clear win.
Quotes and materials for this job
Actual quotes will vary by attic access, existing debris, and whether the job needs air sealing first. Treat the $2,820 figure above as a planning number for Georgetown County, not a bid - contractors typically charge a $600 minimum regardless of job size.
Where these figures come from
Georgetown County's R-49 target and its degree-day figures both come from named federal sources - see the methodology guide for exactly which ones. The guide to what R-value actually means explains why R-49 is the target here specifically.