Brown County, SD Insulation Payback
Brown County, SD: what topping up your attic actually costs
DOE classifies Brown County as climate zone 6, 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 1.5 years at an estimated $2,386/year saved. That's about as fast as attic paybacks get.
Where the savings come from
The estimated savings split roughly $2,297/year heating, $90/year cooling. Out of every 100 US counties tracked here, Brown County's savings potential beats roughly 95 of them. Within zone 6 specifically, it ranks 37th of 459 counties by estimated savings. South Dakota averages $2,162/year across the counties tracked here; Brown County comes in 10% higher.
Brown County's actual weather, not a national average
NOAA's COLUMBIA 8 N, SD US station, 9.5 miles from Brown County, supplies the 8,589 HDD and 558 CDD this estimate runs on. That combined heating-and-cooling load ranks Brown County 130th nationally by total degree days — the 96th percentile. Brown County falls in DOE's moisture regime A (humid), a detail that affects vapor-barrier recommendations more than the R-value target itself.
The smaller top-up scenario
Already have a few inches up there? Topping R-11 up to R-49 runs about $2,280 for about $348/year saved — roughly 6.6 years to break even. That is a solid payback as home upgrades go.
Getting it done in Brown County
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 Brown County's estimated $2,386/year on the line.
Nothing here is a guess
Every figure on this page traces to DOE/IECC climate zones and NOAA degree-day normals, documented in the methodology guide. The guide to what R-value actually means explains why R-60 is the target here specifically.