Clay County, TN Insulation Payback
Clay County attic insulation, by the numbers
Clay 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. 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 $1,320/year saved. Topping up the attic pays for itself fast here.
Where the savings come from
Split it out and it's roughly $1,102 a year on the heating side, $218 on cooling. By estimated insulation savings, Clay County lands in the 40th percentile nationally. Zone 4 alone covers 825 counties in this dataset, and Clay County comes in 545th by savings. Tennessee averages $1,258/year across the counties tracked here; Clay County comes in 5% higher.
The climate data behind this
The heating and cooling degree days behind this estimate — 4,120 HDD and 1,357 CDD (base 65°F, 1991-2020 normals) — come from GAINESBORO, TN US, the nearest NOAA station with published normals, 13.8 miles from Clay County's center. By total degree days, Clay County sits at the 39th percentile nationally. One local detail the R-value alone won't tell you: Clay County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
Already have some insulation?
Already have a few inches up there? Topping R-11 up to R-49 runs about $2,280 for about $192/year saved — roughly 11.8 years to break even. Call this borderline rather than a clear win.
Quotes and materials for this job
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 Clay County's estimated $1,320/year on the line.
Where these figures come from
Clay County's R-60 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-60 is the target here specifically.