Boone County, IL Insulation Payback
Is attic insulation worth it in Boone County, IL?
Boone County sits in IECC climate zone 5 (Cold) — winters that dominate the energy bill, with cooling a minor factor. For a currently uninsulated attic, DOE and ENERGY STAR recommend building up to R-60. For an attic around 1,000 square feet, closing the gap from R-2 to R-60 costs around $3,480 and saves an estimated $1,941 a year — payback in roughly 1.8 years. Few home upgrades pay back that quickly.
Where the savings come from
Heating accounts for about $1,824/year of that and cooling about $117/year — Boone County needs both. Nationally, Boone County ranks in the 79th percentile for insulation savings potential. Compared only against its own climate zone, Boone County places 104th out of 745. Against Illinois's own average of $1,642/year, Boone County runs 18% above that.
Boone County's actual weather, not a national average
The heating and cooling degree days behind this estimate — 6,822 HDD and 726 CDD (base 65°F, 1991-2020 normals) — come from MARENGO, IL US, the nearest NOAA station with published normals, 11.7 miles from Boone County's center. Combined heating and cooling load puts Boone County in the 80th percentile of this 3,162-county dataset. Its moisture regime is classified humid, which matters for whether the attic needs a vapor retarder as part of the job — worth asking a contractor about locally.
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 $283/year saved — roughly 8.1 years to break even. Whether that is worth it depends on how long you plan to stay.
Next steps for a Boone 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 Boone County, not a bid - contractors typically charge a $600 minimum regardless of job size.
Boone County's numbers, sourced
The methodology guide lists exactly which DOE and NOAA sources feed Boone County's numbers, and where the cost assumptions come from. See the DIY vs. contractor guide for whether a job this size is realistic to do yourself.