Clarke County, AL Insulation Payback
Clarke County, AL: what topping up your attic actually costs
DOE classifies Clarke County as climate zone 3, hot-humid — long, muggy summers and mild winters, where cooling dominates the energy bill. Its recommended attic R-value for bare joists is 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 3 years at an estimated $949/year saved. That's about as fast as attic paybacks get.
Where the savings come from
The estimated savings split roughly $607/year heating, $342/year cooling. Out of every 100 US counties tracked here, Clarke County's savings potential beats roughly 13 of them. Within zone 3 specifically, it ranks 575th of 690 counties by estimated savings. Alabama averages $1,001/year across the counties tracked here; Clarke County comes in 5% lower.
Where these numbers come from
NOAA's WHATLEY, AL US station, 6.8 miles from Clarke County, supplies the 2,289 HDD and 2,147 CDD this estimate runs on. That combined heating-and-cooling load ranks Clarke County 2860th nationally by total degree days — the 10th percentile. Clarke 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?
If Clarke 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 $128/year — payback about 12.7 years. This one is a genuine toss-up, not a clear yes.
Next steps for a Clarke County attic
Real bids depend on how easy the attic is to reach and whether old insulation needs removing first, so treat $2,820 as a starting estimate for a Clarke County job, not a quote. Expect at least a $600 minimum charge from most contractors.
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.