Jersey County, IL Insulation Payback
Jersey County, IL: what topping up your attic actually costs
Jersey 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. 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 $1,615 a year in heating and cooling — a payback around 2.2 years.
That's about as fast as attic paybacks get.
Where the savings come from
The estimated savings split roughly $1,430/year heating, $185/year cooling. Out of every 100 US counties tracked here, Jersey County's savings potential beats roughly 60 of them. Within zone 5 specifically, it ranks 627th of 754 counties by estimated savings. Illinois averages $1,642/year across the counties tracked here; Jersey County comes in 2% lower.
Jersey County's actual weather, not a national average
The heating and cooling degree days behind this estimate — 5,348 HDD and 1,152 CDD (base 65°F, 1991-2020 normals) — come from Jerseyville 2 SW, IL US, the nearest NOAA station with published normals, 1.8 miles from Jersey County's center. That combined heating-and-cooling load ranks Jersey County 1219th nationally by total degree days — the 62nd percentile. Jersey 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 $236/year saved (~9.7-year payback). This one is a genuine toss-up, not a clear yes.
Getting it done in Jersey County
Get quotes from at least two local contractors 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 checking upfront given Jersey County's estimated $1,615/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.