Macoupin County, IL Insulation Payback
Macoupin County attic insulation, by the numbers
Macoupin County, Illinois is zone 4 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-60. Topping up a typical 1,000-square-foot attic from bare joists (R-2) to R-60 runs an estimated $3,480, and saves about $1,606 a year in heating and cooling — a payback around 2.2 years. Topping up the attic pays for itself fast here.
Heating vs. cooling in Macoupin County
Split it out and it's roughly $1,422 a year on the heating side, $183 on cooling. By estimated insulation savings, Macoupin County lands in the 60th percentile nationally. Zone 4 alone covers 825 counties in this dataset, and Macoupin County comes in 46th by savings. Illinois averages $1,642/year across the counties tracked here; Macoupin County comes in 2% lower.
Macoupin County's actual weather, not a national average
The heating and cooling degree days behind this estimate — 5,320 HDD and 1,142 CDD (base 65°F, 1991-2020 normals) — come from CARLINVILLE, IL US, the nearest NOAA station with published normals, 3.4 miles from Macoupin County's center. That combined heating-and-cooling load ranks Macoupin County 1230th nationally by total degree days — the 61th percentile. One local detail the R-value alone won't tell you: Macoupin County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
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 $234/year saved (~9.7-year payback). Call this borderline rather than a clear win.
Quotes and materials for this job
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 Macoupin County job, not a quote. Expect at least a $600 minimum charge from most contractors.
Where these figures come from
Macoupin County's R-60 target and its degree-day figures both come from named federal sources - see the methodology guide for exactly which ones. The guide to what R-value actually means explains why R-60 is the target here specifically.