DeKalb County, GA Insulation Payback
DeKalb County, GA: what topping up your attic actually costs
DeKalb County sits in IECC climate zone 3 (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-49. Going from R-2 to the recommended R-49 costs roughly $2,820 installed for a typical attic (about 1,000 sq ft), and pays for itself in about 2.6 years at an estimated $1,066/year saved. That's about as fast as attic paybacks get.
Heating vs. cooling in DeKalb County
The estimated savings split roughly $791/year heating, $276/year cooling. Out of every 100 US counties tracked here, DeKalb County's savings potential beats roughly 22 of them. Within zone 3 specifically, it ranks 317th of 690 counties by estimated savings. Georgia averages $974/year across the counties tracked here; DeKalb County comes in 9% higher.
The climate data behind this
NOAA's ATLANTA PEACHTREE AP, GA US station, 8.4 miles from DeKalb County, supplies the 2,980 HDD and 1,729 CDD this estimate runs on. Combined heating and cooling load puts DeKalb County in the 17th percentile of this 3,162-county dataset. DeKalb County falls in DOE's moisture regime A (humid), a detail that affects vapor-barrier recommendations more than the R-value target itself.
The smaller top-up scenario
If DeKalb County's attic already has 3-4 inches of old insulation (about R-11) rather than bare joists, the recommended target drops to R-38. That smaller top-up costs around $1,620 and saves an estimated $144/year — payback about 11.3 years. 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 $2,820 figure above as a planning number for DeKalb 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-49 is the target here specifically.