Lewis County, KY Insulation Payback
Is attic insulation worth it in Lewis County, KY?
Lewis County, Kentucky is zone 4 under DOE's climate map (Mixed-Humid), which means a genuine mix of cold winters and humid summers, with neither one dominating the bill. An uninsulated attic there should be built up to R-60. Topping up a typical 1,000-square-foot attic from bare joists (R-2) to R-60 runs an estimated $3,480, and saves about $1,429 a year in heating and cooling — a payback around 2.4 years. Few home upgrades pay back that quickly.
The breakdown behind the number
Heating accounts for about $1,274/year of that and cooling about $155/year — Lewis County needs both. Nationally, Lewis County ranks in the 48th percentile for insulation savings potential. Compared only against its own climate zone, Lewis County places 322nd out of 825. Against Kentucky's own average of $1,385/year, Lewis County runs 3% above that.
The climate data behind this
The heating and cooling degree days behind this estimate — 4,763 HDD and 966 CDD (base 65°F, 1991-2020 normals) — come from WARNOCK 2, KY US, the nearest NOAA station with published normals, 19.2 miles from Lewis County's center. That combined heating-and-cooling load ranks Lewis County 1725th nationally by total degree days — the 45th 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.
The smaller top-up scenario
If Lewis County's attic already has 3-4 inches of old insulation (about R-11) rather than bare joists, the recommended target drops to R-49. That smaller top-up costs around $2,280 and saves an estimated $208/year — payback about 10.9 years. 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 $3,480 figure above as a planning number for Lewis County, not a bid - contractors typically charge a $600 minimum regardless of job size.
Lewis County's numbers, sourced
The methodology guide lists exactly which DOE and NOAA sources feed Lewis 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.