Marshall County, MS Insulation Payback
Is attic insulation worth it in Marshall County, MS?
Marshall County, Mississippi is zone 3 under DOE's climate map (Mixed-Humid), which means real heating and real cooling seasons both, roughly balanced across the year. An uninsulated attic there should be built up to R-49. Going from R-2 to the recommended R-49 costs roughly $2,820 installed for a typical attic (about 1,000 sq ft), and pays for itself in about 2.4 years at an estimated $1,176/year saved. Few home upgrades pay back that quickly.
Where the savings come from
Heating accounts for about $904/year of that and cooling about $272/year — Marshall County needs both. Nationally, Marshall County ranks in the 29th percentile for insulation savings potential. Compared only against its own climate zone, Marshall County places 123rd out of 690. Against Mississippi's own average of $1,022/year, Marshall County runs 15% above that.
The climate data behind this
NOAA's HOLLY SPRINGS 4 N, MS US station, 5.5 miles from Marshall County, supplies the 3,406 HDD and 1,709 CDD this estimate runs on. That combined heating-and-cooling load ranks Marshall County 2245th nationally by total degree days — the 29th percentile. Its moisture regime is classified humid, which matters for whether the attic needs a vapor retarder as part of the job — worth asking a contractor about locally.
If the attic isn't bare
A shallower starting point changes the math: with R-11 already down, only the gap to R-38 needs filling, at roughly $1,620 for an estimated $158/year saved (~10.2-year payback). Whether that is worth it depends on how long you plan to stay.
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 Marshall County, not a bid - contractors typically charge a $600 minimum regardless of job size.
Marshall County's numbers, sourced
The methodology guide lists exactly which DOE and NOAA sources feed Marshall County's numbers, and where the cost assumptions come from. See the DIY vs. contractor guide for whether a job this size is realistic to do yourself.