Cass County, IL Insulation Payback
Cass County attic insulation, by the numbers
Cass County sits in IECC climate zone 5 (Cold) — cold enough that heating, not cooling, is what decides the bill. For a currently uninsulated attic, DOE and ENERGY STAR recommend building 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 $1,645/year saved. Topping up the attic pays for itself fast here.
Heating vs. cooling in Cass County
Split it out and it's roughly $1,473 a year on the heating side, $172 on cooling. By estimated insulation savings, Cass County lands in the 63th percentile nationally. Zone 5 alone covers 745 counties in this dataset, and Cass County comes in 579th by savings. Illinois averages $1,642/year across the counties tracked here; Cass County comes in 0% higher.
Where these numbers come from
Cass County's climate figures — 5,510 heating and 1,068 cooling degree days a year — are read from JACKSONVILLE 2E, IL US, 16.4 miles away, NOAA's nearest 1991-2020 normals station. That combined heating-and-cooling load ranks Cass County 1162nd nationally by total degree days — the 63th percentile. One local detail the R-value alone won't tell you: Cass 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 $240/year saved (~9.5-year payback). Call this borderline rather than a clear win.
Next steps for a Cass 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 Cass County's estimated $1,645/year on the line.
Where these figures come from
Cass 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.