Tama County, IA Insulation Payback
Tama County attic insulation, by the numbers
DOE classifies Tama County as climate zone 5, cold — winters that dominate the energy bill, with cooling a minor factor. Its recommended attic R-value for bare joists is R-60. Topping up a typical 1,000-square-foot attic from bare joists (R-2) to R-60 runs an estimated $3,480, and saves about $2,016 a year in heating and cooling — a payback around 1.7 years. Topping up the attic pays for itself fast here.
The breakdown behind the number
Split it out and it's roughly $1,902 a year on the heating side, $113 on cooling. By estimated insulation savings, Tama County lands in the 83th percentile nationally. Zone 5 alone covers 745 counties in this dataset, and Tama County comes in 35th by savings. Iowa averages $1,985/year across the counties tracked here; Tama County comes in 2% higher.
The climate data behind this
NOAA's TOLEDO 3N, IA US station, 3.8 miles from Tama County, supplies the 7,115 HDD and 704 CDD this estimate runs on. That combined heating-and-cooling load ranks Tama County 516th nationally by total degree days — the 84th percentile. One local detail the R-value alone won't tell you: Tama County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
Already have some insulation?
Already have a few inches up there? Topping R-11 up to R-49 runs about $2,280 for about $294/year saved — roughly 7.8 years to break even. Worth doing on the numbers alone.
Next steps for a Tama County attic
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 Tama County's estimated $2,016/year on the line.
Where these figures come from
Tama 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.