InsulationPayback

Monroe County, IL Insulation Payback

Monroe County, IL: what topping up your attic actually costs

Monroe County sits in IECC climate zone 4 (Mixed-Humid) — heating load in winter and cooling load in summer, both worth taking seriously here. For a currently uninsulated attic, DOE and ENERGY STAR recommend building 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 2.4 years at an estimated $1,474/year saved. That's about as fast as attic paybacks get.

Heating vs. cooling in Monroe County

The estimated savings split roughly $1,257/year heating, $217/year cooling. Out of every 100 US counties tracked here, Monroe County's savings potential beats roughly 51 of them. Within zone 4 specifically, it ranks 221st of 825 counties by estimated savings. Illinois averages $1,642/year across the counties tracked here; Monroe County comes in 10% lower.

Monroe County's actual weather, not a national average

Monroe County's climate figures — 4,700 heating and 1,352 cooling degree days a year — are read from FESTUS, MO US, 12.3 miles away, NOAA's nearest 1991-2020 normals station. Combined heating and cooling load puts Monroe County in the 53th percentile of this 3,162-county dataset. Monroe 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 $215/year saved (~10.6-year payback). This one is a genuine toss-up, not a clear yes.

Next steps for a Monroe 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 Monroe 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.