Humphreys County, MS Insulation Payback
Humphreys County, MS: what topping up your attic actually costs
Humphreys County, Mississippi is zone 3 under DOE's climate map (Mixed-Humid), which means real heating and real cooling seasons both, roughly balanced across the year. An uninsulated attic there should be built up to R-49. Topping up a typical 1,000-square-foot attic from bare joists (R-2) to R-49 runs an estimated $2,820, and saves about $1,039 a year in heating and cooling — a payback around 2.7 years. That's about as fast as attic paybacks get.
Where the savings come from
The estimated savings split roughly $667/year heating, $371/year cooling. Out of every 100 US counties tracked here, Humphreys County's savings potential beats roughly 19 of them. Within zone 3 specifically, it ranks 388th of 690 counties by estimated savings. Mississippi averages $1,022/year across the counties tracked here; Humphreys County comes in 2% higher.
Where these numbers come from
The heating and cooling degree days behind this estimate — 2,515 HDD and 2,331 CDD (base 65°F, 1991-2020 normals) — come from BELZONI, MS US, the nearest NOAA station with published normals, 3.7 miles from Humphreys County's center. By total degree days, Humphreys County sits at the 21th percentile nationally. Humphreys County falls in DOE's moisture regime A (humid), a detail that affects vapor-barrier recommendations more than the R-value target itself.
If the attic isn't bare
If Humphreys 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 $140/year — payback about 11.6 years. This one is a genuine toss-up, not a clear yes.
Next steps for a Humphreys County attic
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 Humphreys County's estimated $1,039/year on the line.
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.