Bannock County, ID Insulation Payback
Bannock County attic insulation, by the numbers
DOE classifies Bannock County as climate zone 6, 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 $1,986 a year in heating and cooling — a payback around 1.8 years. Topping up the attic pays for itself fast here.
The breakdown behind the number
Split it out and it's roughly $1,930 a year on the heating side, $56 on cooling. By estimated insulation savings, Bannock County lands in the 81th percentile nationally. Zone 6 alone covers 459 counties in this dataset, and Bannock County comes in 404th by savings. Idaho averages $1,995/year across the counties tracked here; Bannock County comes in 0% higher.
Bannock County's actual weather, not a national average
Bannock County's climate figures — 7,219 heating and 348 cooling degree days a year — are read from MCCAMMON, ID US, 3.3 miles away, NOAA's nearest 1991-2020 normals station. By total degree days, Bannock County sits at the 80th percentile nationally. One local detail the R-value alone won't tell you: Bannock County sits in moisture regime B (dry), which can affect the vapor-barrier choice.
The smaller top-up scenario
If Bannock County's attic already has 3-4 inches of old insulation (about R-11) rather than bare joists, the recommended target drops to R-49. That smaller top-up costs around $2,280 and saves an estimated $290/year — payback about 7.9 years. Worth doing on the numbers alone.
Quotes and materials for this job
Real bids depend on how easy the attic is to reach and whether old insulation needs removing first, so treat $3,480 as a starting estimate for a Bannock County job, not a quote. Expect at least a $600 minimum charge from most contractors.
Where these figures come from
Bannock 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.