Wilson County, TN Insulation Payback
Is attic insulation worth it in Wilson County, TN?
Wilson County, Tennessee 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 $1,285 a year in heating and cooling — a payback around 2.7 years. Few home upgrades pay back that quickly.
Where the savings come from
Heating accounts for about $1,017/year of that and cooling about $268/year — Wilson County needs both. Nationally, Wilson County ranks in the 37th percentile for insulation savings potential. Compared only against its own climate zone, Wilson County places 616th out of 825. Against Tennessee's own average of $1,258/year, Wilson County runs 2% above that.
Wilson County's actual weather, not a national average
The heating and cooling degree days behind this estimate — 3,802 HDD and 1,671 CDD (base 65°F, 1991-2020 normals) — come from LEBANON, TN US, the nearest NOAA station with published normals, 5.7 miles from Wilson County's center. That combined heating-and-cooling load ranks Wilson County 1925th nationally by total degree days — the 39th 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-49 needs filling, at roughly $2,280 for an estimated $187/year saved (~12.2-year payback). Whether that is worth it depends on how long you plan to stay.
Next steps for a Wilson County attic
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 Wilson County, not a bid - contractors typically charge a $600 minimum regardless of job size.
Wilson County's numbers, sourced
The methodology guide lists exactly which DOE and NOAA sources feed Wilson 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.