Peoria County, IL Insulation Payback
Peoria County, IL: what topping up your attic actually costs
Peoria 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 $1,687 a year in heating and cooling — a payback around 2.1 years. That's about as fast as attic paybacks get.
The breakdown behind the number
The estimated savings split roughly $1,501/year heating, $186/year cooling. Out of every 100 US counties tracked here, Peoria County's savings potential beats roughly 65 of them. Within zone 5 specifically, it ranks 503rd of 745 counties by estimated savings. Illinois averages $1,642/year across the counties tracked here; Peoria County comes in 3% higher.
Peoria County's actual weather, not a national average
NOAA's PEORIA GTR PEORIA AP, IL US station, 9.3 miles from Peoria County, supplies the 5,614 HDD and 1,157 CDD this estimate runs on. Combined heating and cooling load puts Peoria County in the 67th percentile of this 3,162-county dataset. Peoria County falls in DOE's moisture regime A (humid), a detail that affects vapor-barrier recommendations more than the R-value target itself.
Already have some insulation?
If Peoria County's attic already has 3-4 inches of old insulation (about R-11) rather than bare joists, the recommended target drops to R-49. That smaller top-up costs around $2,280 and saves an estimated $246/year — payback about 9.3 years. This one is a genuine toss-up, not a clear yes.
Quotes and materials for this job
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 Peoria County's estimated $1,687/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.