Hamblen County, TN Insulation Payback
Hamblen County attic insulation, by the numbers
Hamblen County sits in IECC climate zone 4 (Mixed-Humid) — real heating and real cooling seasons both, roughly balanced across the year. For a currently uninsulated attic, DOE and ENERGY STAR recommend building 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 $1,275 a year in heating and cooling — a payback around 2.7 years. Topping up the attic pays for itself fast here.
Where the savings come from
Split it out and it's roughly $1,074 a year on the heating side, $201 on cooling. By estimated insulation savings, Hamblen County lands in the 37th percentile nationally. Zone 4 alone covers 825 counties in this dataset, and Hamblen County comes in 630th by savings. Tennessee averages $1,258/year across the counties tracked here; Hamblen County comes in 1% higher.
The climate data behind this
NOAA's MORRISTOWN RADIO WCRK, TN US station, 3.8 miles from Hamblen County, supplies the 4,017 HDD and 1,252 CDD this estimate runs on. That combined heating-and-cooling load ranks Hamblen County 2115th nationally by total degree days — the 33th percentile. One local detail the R-value alone won't tell you: Hamblen County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
The smaller top-up scenario
Already have a few inches up there? Topping R-11 up to R-49 runs about $2,280 for about $186/year saved — roughly 12.3 years to break even. Call this borderline rather than a clear win.
Getting it done in Hamblen County
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 Hamblen County, not a bid - contractors typically charge a $600 minimum regardless of job size.
Where these figures come from
Hamblen 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.