Mills County, IA Insulation Payback
Mills County attic insulation, by the numbers
Mills County, Iowa is zone 5 under DOE's climate map (Cold), which means winters that dominate the energy bill, with cooling a minor factor. 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 $1,826/year saved. Topping up the attic pays for itself fast here.
Where the savings come from
Split it out and it's roughly $1,655 a year on the heating side, $172 on cooling. By estimated insulation savings, Mills County lands in the 74th percentile nationally. Zone 5 alone covers 745 counties in this dataset, and Mills County comes in 253rd by savings. Iowa averages $1,985/year across the counties tracked here; Mills County comes in 8% lower.
Mills County's actual weather, not a national average
Mills County's climate figures — 6,188 heating and 1,070 cooling degree days a year — are read from GLENWOOD 3SW, IA US, 8.2 miles away, NOAA's nearest 1991-2020 normals station. That combined heating-and-cooling load ranks Mills County 761st nationally by total degree days — the 76th percentile. One local detail the R-value alone won't tell you: Mills County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
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 $266/year saved (~8.6-year payback). Call this borderline rather than a clear win.
Getting it done in Mills County
Get more than one quote before committing. Attic access and any needed air sealing move the price around, and most contractors won't take a job below roughly $600 regardless of size - worth asking upfront given Mills County's estimated $1,826/year on the line.
Where these figures come from
Mills County's R-60 target and its degree-day figures both come from named federal sources - see the methodology guide for exactly which ones. The guide to what R-value actually means explains why R-60 is the target here specifically.