Macon County, IL Insulation Payback
Macon County, IL: what topping up your attic actually costs
Macon County, Illinois is zone 5 under DOE's climate map (Cold), which means a real winter that drives most of the annual energy bill here. 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 2.1 years at an estimated $1,635/year saved. That's about as fast as attic paybacks get.
Where the savings come from
The estimated savings split roughly $1,455/year heating, $179/year cooling. Out of every 100 US counties tracked here, Macon County's savings potential beats roughly 62 of them. Within zone 5 specifically, it ranks 595th of 745 counties by estimated savings. Illinois averages $1,642/year across the counties tracked here; Macon County comes in 0% higher.
Where these numbers come from
The heating and cooling degree days behind this estimate — 5,443 HDD and 1,116 CDD (base 65°F, 1991-2020 normals) — come from DECATUR WTP, IL US, the nearest NOAA station with published normals, 2.2 miles from Macon County's center. Combined heating and cooling load puts Macon County in the 63th percentile of this 3,162-county dataset. Macon 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 $238/year saved (~9.6-year payback). This one is a genuine toss-up, not a clear yes.
Getting it done in Macon County
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 Macon County's estimated $1,635/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-60 is the target here specifically.