Lyman County, SD Insulation Payback
Attic insulation payback for Lyman County, SD
DOE classifies Lyman 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 $2,032 a year in heating and cooling — a payback around 1.7 years. Hard to find a home improvement with a faster payback than this.
The breakdown behind the number
Of that, about $1,883/year comes from reduced heating and $149/year from reduced cooling load through the ceiling. Lyman County beats 83% of the counties in this 3,162-county dataset on estimated insulation savings. Among the 459 counties DOE places in zone 6, Lyman County ranks 373rd. Against South Dakota's own average of $2,162/year, Lyman County runs 6% below that.
The climate data behind this
The heating and cooling degree days behind this estimate — 7,042 HDD and 929 CDD (base 65°F, 1991-2020 normals) — come from KENNEBEC, SD US, the nearest NOAA station with published normals, 1 miles from Lyman County's center. By total degree days, Lyman County sits at the 85th percentile nationally. DOE also classifies Lyman County as moisture regime A (humid) - ask a local contractor whether that changes the vapor-barrier approach for this job.
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 $296/year saved — roughly 7.7 years to break even. Topping up the attic pays for itself here.
Next steps for a Lyman County attic
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 Lyman County job, not a quote. Expect at least a $600 minimum charge from most contractors.
More on how this was built
Nothing here is a guess: the methodology guide names the DOE climate map and NOAA station data behind every number on this page. See the DIY vs. contractor guide for whether a job this size is realistic to do yourself.