Massac County, IL Insulation Payback
Massac County, IL: what topping up your attic actually costs
DOE classifies Massac County as climate zone 4, mixed-humid — real heating and real cooling seasons both, roughly balanced across the year. 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 2.5 years at an estimated $1,379/year saved. That's about as fast as attic paybacks get.
Where the savings come from
The estimated savings split roughly $1,141/year heating, $238/year cooling. Out of every 100 US counties tracked here, Massac County's savings potential beats roughly 44 of them. Within zone 4 specifically, it ranks 426th of 825 counties by estimated savings. Illinois averages $1,642/year across the counties tracked here; Massac County comes in 16% lower.
Massac County's actual weather, not a national average
Massac County's climate figures — 4,267 heating and 1,481 cooling degree days a year — are read from BROOKPORT DAM 52, IL US, 6.8 miles away, NOAA's nearest 1991-2020 normals station. That combined heating-and-cooling load ranks Massac County 1709th nationally by total degree days — the 46th percentile. Massac 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
Already have a few inches up there? Topping R-11 up to R-49 runs about $2,280 for about $201/year saved — roughly 11.3 years to break even. This one is a genuine toss-up, not a clear yes.
Next steps for a Massac 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 Massac 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.