Davis County, IA Insulation Payback
Davis County attic insulation, by the numbers
DOE classifies Davis County as climate zone 5, cold — cold enough that heating, not cooling, is what decides 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 years at an estimated $1,781/year saved.
Topping up the attic pays for itself fast here.
The breakdown behind the number
Split it out and it's roughly $1,614 a year on the heating side, $168 on cooling. By estimated insulation savings, Davis County lands in the 71st percentile nationally. Zone 5 alone covers 754 counties in this dataset, and Davis County comes in 335th by savings. Iowa averages $1,985/year across the counties tracked here; Davis County comes in 10% lower.
Davis County's actual weather, not a national average
NOAA's Bloomfield, IA US station, 0.6 miles from Davis County, supplies the 6,035 HDD and 1,044 CDD this estimate runs on. By total degree days, Davis County sits at the 73rd percentile nationally. One local detail the R-value alone won't tell you: Davis County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
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 $260/year saved — roughly 8.8 years to break even. Call this borderline rather than a clear win.
Next steps for a Davis County attic
Get quotes from at least two local contractors 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 checking upfront given Davis County's estimated $1,781/year on the line.
Where these figures come from
Davis 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.