Claiborne County, TN Insulation Payback
Claiborne County, TN: what topping up your attic actually costs
DOE classifies Claiborne County as climate zone 4, mixed-humid — real heating and real cooling seasons both, roughly balanced across the year. Its recommended attic R-value for bare joists is 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 $1,423 a year in heating and cooling — a payback around 2.4 years. That's about as fast as attic paybacks get.
The breakdown behind the number
The estimated savings split roughly $1,280/year heating, $143/year cooling. Out of every 100 US counties tracked here, Claiborne County's savings potential beats roughly 47 of them. Within zone 4 specifically, it ranks 335th of 825 counties by estimated savings. Tennessee averages $1,258/year across the counties tracked here; Claiborne County comes in 13% higher.
Claiborne County's actual weather, not a national average
The heating and cooling degree days behind this estimate — 4,786 HDD and 893 CDD (base 65°F, 1991-2020 normals) — come from TAZEWELL, TN US, the nearest NOAA station with published normals, 6.1 miles from Claiborne County's center. That combined heating-and-cooling load ranks Claiborne County 1767th nationally by total degree days — the 44th percentile. Claiborne County falls in DOE's moisture regime A (humid), a detail that affects vapor-barrier recommendations more than the R-value target itself.
Already have some insulation?
Already have a few inches up there? Topping R-11 up to R-49 runs about $2,280 for about $208/year saved — roughly 11 years to break even. This one is a genuine toss-up, not a clear yes.
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 Claiborne County, not a bid - contractors typically charge a $600 minimum regardless of job size.
Nothing here is a guess
Every figure on this page traces to DOE/IECC climate zones and NOAA degree-day normals, documented in the methodology guide. The guide to what R-value actually means explains why R-60 is the target here specifically.