Simpson County, MS Insulation Payback
Simpson County, MS: what topping up your attic actually costs
Simpson County, Mississippi is zone 3 under DOE's climate map (Hot-Humid), which means long, muggy summers and mild winters, where cooling dominates the energy bill. An uninsulated attic there should be built 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 3 years at an estimated $951/year saved. That's about as fast as attic paybacks get.
The breakdown behind the number
The estimated savings split roughly $501/year heating, $450/year cooling. Out of every 100 US counties tracked here, Simpson County's savings potential beats roughly 13 of them. Within zone 3 specifically, it ranks 570th of 690 counties by estimated savings. Mississippi averages $1,022/year across the counties tracked here; Simpson County comes in 7% lower.
Simpson County's actual weather, not a national average
Simpson County's climate figures — 1,888 heating and 2,826 cooling degree days a year — are read from D'LO 2 SW, MS US, 3.7 miles away, NOAA's nearest 1991-2020 normals station. By total degree days, Simpson County sits at the 17th percentile nationally. Simpson 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 Simpson 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 12.6 years. This one is a genuine toss-up, not a clear yes.
Getting it done in Simpson County
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 Simpson 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.