Henry County, IL Insulation Payback
Henry County, IL: what topping up your attic actually costs
Henry County, Illinois is zone 5 under DOE's climate map (Cold), which means cold enough that heating, not cooling, is what decides the bill. 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 1.9 years at an estimated $1,807/year saved. That's about as fast as attic paybacks get.
The breakdown behind the number
The estimated savings split roughly $1,641/year heating, $166/year cooling. Out of every 100 US counties tracked here, Henry County's savings potential beats roughly 73 of them. Within zone 5 specifically, it ranks 281st of 745 counties by estimated savings. Illinois averages $1,642/year across the counties tracked here; Henry County comes in 10% higher.
The climate data behind this
NOAA's GENESEO, IL US station, 7 miles from Henry County, supplies the 6,139 HDD and 1,031 CDD this estimate runs on. Combined heating and cooling load puts Henry County in the 75th percentile of this 3,162-county dataset. Henry 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
If Henry 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 $264/year — payback about 8.6 years. This one is a genuine toss-up, not a clear yes.
Getting it done in Henry County
Actual quotes will vary by attic access, existing debris, and whether the job needs air sealing first. Treat the $3,480 figure above as a planning number for Henry County, not a bid - contractors typically charge a $600 minimum regardless of job size.
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.