Forrest County, MS Insulation Payback
Forrest County attic insulation, by the numbers
DOE classifies Forrest 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. Topping up a typical 1,000-square-foot attic from bare joists (R-2) to R-49 runs an estimated $2,820, and saves about $904 a year in heating and cooling — a payback around 3.1 years. Topping up the attic pays for itself here.
Heating vs. cooling in Forrest County
Split it out and it's roughly $509 a year on the heating side, $395 on cooling. By estimated insulation savings, Forrest County lands in the 10th percentile nationally. Zone 3 alone covers 690 counties in this dataset, and Forrest County comes in 637th by savings. Mississippi averages $1,022/year across the counties tracked here; Forrest County comes in 12% lower.
Forrest County's actual weather, not a national average
Forrest County's climate figures — 1,920 heating and 2,479 cooling degree days a year — are read from HATTIESBURG CHAIN MUNI AP, MS US, 6.5 miles away, NOAA's nearest 1991-2020 normals station. By total degree days, Forrest County sits at the 9th percentile nationally. One local detail the R-value alone won't tell you: Forrest County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
The smaller top-up scenario
If Forrest 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 $122/year — payback about 13.3 years. Call this borderline rather than a clear win.
Quotes and materials for this job
Real bids depend on how easy the attic is to reach and whether old insulation needs removing first, so treat $2,820 as a starting estimate for a Forrest County job, not a quote. Expect at least a $600 minimum charge from most contractors.
Where these figures come from
Forrest 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.