McCook County, SD Insulation Payback
McCook County attic insulation, by the numbers
DOE classifies McCook County as climate zone 6, cold — a real winter that drives most of the annual energy bill here. Its recommended attic R-value for bare joists is 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 $2,248 a year — payback in roughly 1.5 years. Topping up the attic pays for itself fast here.
The breakdown behind the number
Split it out and it's roughly $2,153 a year on the heating side, $94 on cooling. By estimated insulation savings, McCook County lands in the 92th percentile nationally. Zone 6 alone covers 459 counties in this dataset, and McCook County comes in 142nd by savings. South Dakota averages $2,162/year across the counties tracked here; McCook County comes in 4% higher.
Where these numbers come from
The heating and cooling degree days behind this estimate — 8,053 HDD and 588 CDD (base 65°F, 1991-2020 normals) — come from SALEM 5NE, SD US, the nearest NOAA station with published normals, 5.1 miles from McCook County's center. By total degree days, McCook County sits at the 92th percentile nationally. One local detail the R-value alone won't tell you: McCook County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
The smaller top-up scenario
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 $328/year saved (~7-year payback). 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 McCook County job, not a quote. Expect at least a $600 minimum charge from most contractors.
Where these figures come from
McCook 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.