Cannon County, TN Insulation Payback
Cannon County attic insulation, by the numbers
Cannon 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 $1,245 a year in heating and cooling — a payback around 2.8 years. Topping up the attic pays for itself fast here.
The breakdown behind the number
Split it out and it's roughly $1,015 a year on the heating side, $230 on cooling. By estimated insulation savings, Cannon County lands in the 34th percentile nationally. Zone 4 alone covers 825 counties in this dataset, and Cannon County comes in 693rd by savings. Tennessee averages $1,258/year across the counties tracked here; Cannon County comes in 1% lower.
The climate data behind this
The heating and cooling degree days behind this estimate — 3,796 HDD and 1,429 CDD (base 65°F, 1991-2020 normals) — come from WOODBURY 1 WNW, TN US, the nearest NOAA station with published normals, 2.5 miles from Cannon County's center. By total degree days, Cannon County sits at the 32th percentile nationally. One local detail the R-value alone won't tell you: Cannon 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 $182/year saved — roughly 12.6 years to break even. Call this borderline rather than a clear win.
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 Cannon County, not a bid - contractors typically charge a $600 minimum regardless of job size.
Where these figures come from
Cannon 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.