DeKalb County, TN Insulation Payback
DeKalb County attic insulation, by the numbers
DeKalb 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. For an attic around 1,000 square feet, closing the gap from R-2 to R-60 costs around $3,480 and saves an estimated $1,307 a year — payback in roughly 2.7 years. Topping up the attic pays for itself fast here.
Heating vs. cooling in DeKalb County
Split it out and it's roughly $1,109 a year on the heating side, $198 on cooling. By estimated insulation savings, DeKalb County lands in the 39th percentile nationally. Zone 4 alone covers 825 counties in this dataset, and DeKalb County comes in 570th by savings. Tennessee averages $1,258/year across the counties tracked here; DeKalb County comes in 4% higher.
Where these numbers come from
DeKalb County's climate figures — 4,148 heating and 1,231 cooling degree days a year — are read from SMITHVILLE 2 SE, TN US, 3.7 miles away, NOAA's nearest 1991-2020 normals station. That combined heating-and-cooling load ranks DeKalb County 1998th nationally by total degree days — the 37th percentile. One local detail the R-value alone won't tell you: DeKalb 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 $191/year saved — roughly 12 years to break even. Call this borderline rather than a clear win.
Getting it done in DeKalb County
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 DeKalb County's estimated $1,307/year on the line.
Where these figures come from
DeKalb 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.