Crawford County, IL Insulation Payback
Crawford County, IL: what topping up your attic actually costs
DOE classifies Crawford County as climate zone 4, mixed-humid — a genuine mix of cold winters and humid summers, with neither one dominating the bill. Its recommended attic R-value for bare joists is 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 2.2 years at an estimated $1,583/year saved. That's about as fast as attic paybacks get.
Where the savings come from
The estimated savings split roughly $1,382/year heating, $201/year cooling. Out of every 100 US counties tracked here, Crawford County's savings potential beats roughly 58 of them. Within zone 4 specifically, it ranks 67th of 825 counties by estimated savings. Illinois averages $1,642/year across the counties tracked here; Crawford County comes in 4% lower.
Crawford County's actual weather, not a national average
NOAA's ROBINSON, IL US station, 0.9 miles from Crawford County, supplies the 5,170 HDD and 1,249 CDD this estimate runs on. That combined heating-and-cooling load ranks Crawford County 1259th nationally by total degree days — the 60th percentile. Crawford County falls in DOE's moisture regime A (humid), a detail that affects vapor-barrier recommendations more than the R-value target itself.
The smaller top-up scenario
If Crawford 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 $231/year — payback about 9.9 years. This one is a genuine toss-up, not a clear yes.
Next steps for a Crawford County attic
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 Crawford 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.