Union County, SD Insulation Payback

Is attic insulation worth it in Union County, SD?

Union County, South Dakota is zone 5 under DOE's climate map (Cold), which means a real winter that drives most of the annual energy bill here. An uninsulated attic there should be built up to 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 1.8 years at an estimated $1,952/year saved. Few home upgrades pay back that quickly.

The breakdown behind the number

Heating accounts for about $1,807/year of that and cooling about $145/year — Union County needs both. Nationally, Union County ranks in the 80th percentile for insulation savings potential. Compared only against its own climate zone, Union County places 93rd out of 745. Against South Dakota's own average of $2,162/year, Union County runs 10% below that.

Where these numbers come from

NOAA's VERMILLION 2 SE, SD US station, 14.4 miles from Union County, supplies the 6,758 HDD and 904 CDD this estimate runs on. By total degree days, Union County sits at the 81th percentile nationally. Its moisture regime is classified humid, which matters for whether the attic needs a vapor retarder as part of the job — worth asking a contractor about locally.

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 $285/year saved — roughly 8 years to break even. Whether that is worth it depends on how long you plan to stay.

Getting it done in Union 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 Union County's estimated $1,952/year on the line.

Union County's numbers, sourced

The methodology guide lists exactly which DOE and NOAA sources feed Union County's numbers, and where the cost assumptions come from. See the DIY vs. contractor guide for whether a job this size is realistic to do yourself.