Perry County, IL Insulation Payback
Perry County, IL: what topping up your attic actually costs
Perry County, Illinois is zone 4 under DOE's climate map (Mixed-Humid), which means a genuine mix of cold winters and humid summers, with neither one dominating the bill. An uninsulated attic there should be built up to R-60. Going from R-2 to the recommended R-60 costs roughly $3,480 installed for a typical attic (about 1,000 sq ft), and pays for itself in about 2.4 years at an estimated $1,434/year saved. That's about as fast as attic paybacks get.
Where the savings come from
The estimated savings split roughly $1,220/year heating, $213/year cooling. Out of every 100 US counties tracked here, Perry County's savings potential beats roughly 48 of them. Within zone 4 specifically, it ranks 302nd of 825 counties by estimated savings. Illinois averages $1,642/year across the counties tracked here; Perry County comes in 13% lower.
Perry County's actual weather, not a national average
The heating and cooling degree days behind this estimate — 4,564 HDD and 1,329 CDD (base 65°F, 1991-2020 normals) — come from DU QUOIN 4 SE, IL US, the nearest NOAA station with published normals, 11.6 miles from Perry County's center. Combined heating and cooling load puts Perry County in the 49th percentile of this 3,162-county dataset. Perry 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
A shallower starting point changes the math: with R-11 already down, only the gap to R-49 needs filling, at roughly $2,280 for an estimated $209/year saved (~10.9-year payback). This one is a genuine toss-up, not a clear yes.
Next steps for a Perry County attic
Real bids depend on how easy the attic is to reach and whether old insulation needs removing first, so treat $3,480 as a starting estimate for a Perry 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-60 is the target here specifically.