Marshall County, KY Insulation Payback
Is attic insulation worth it in Marshall County, KY?
DOE classifies Marshall County as climate zone 4, mixed-humid — a genuine mix of cold winters and humid summers, with neither one dominating the bill. Its recommended attic R-value for bare joists is R-60. Going from R-2 to the recommended R-60 costs roughly $3,480 installed for a typical attic (about 1,000 sq ft), and pays for itself in about 2.6 years at an estimated $1,353/year saved. Few home upgrades pay back that quickly.
Heating vs. cooling in Marshall County
Heating accounts for about $1,140/year of that and cooling about $213/year — Marshall County needs both. Nationally, Marshall County ranks in the 42th percentile for insulation savings potential. Compared only against its own climate zone, Marshall County places 479th out of 825. Against Kentucky's own average of $1,385/year, Marshall County runs 2% below that.
Marshall County's actual weather, not a national average
The heating and cooling degree days behind this estimate — 4,262 HDD and 1,329 CDD (base 65°F, 1991-2020 normals) — come from BENTON, KY US, the nearest NOAA station with published normals, 1.7 miles from Marshall County's center. Combined heating and cooling load puts Marshall County in the 42th percentile of this 3,162-county dataset. 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-49 needs filling, at roughly $2,280 for an estimated $197/year saved (~11.6-year payback). Whether that is worth it depends on how long you plan to stay.
Next steps for a Marshall County attic
Get more than one quote before committing. Attic access and any needed air sealing move the price around, and most contractors won't take a job below roughly $600 regardless of size - worth asking upfront given Marshall County's estimated $1,353/year on the line.
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.