Jefferson County, WI Insulation Payback
Attic insulation payback for Jefferson County, WI
DOE classifies Jefferson 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 $2,014 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 $1,905/year comes from reduced heating and $109/year from reduced cooling load through the ceiling. Jefferson 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, Jefferson County ranks 383rd. Against Wisconsin's own average of $2,200/year, Jefferson County runs 8% below that.
Where these numbers come from
The heating and cooling degree days behind this estimate — 7,125 HDD and 678 CDD (base 65°F, 1991-2020 normals) — come from JEFFERSON WWTP, WI US, the nearest NOAA station with published normals, 2 miles from Jefferson County's center. By total degree days, Jefferson County sits at the 83th percentile nationally. DOE also classifies Jefferson County as moisture regime A (humid) - ask a local contractor whether that changes the vapor-barrier approach for this job.
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 $294/year saved (~7.8-year payback). Topping up the attic pays for itself here.
Quotes and materials for this job
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 Jefferson County's estimated $2,014/year on the line.
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.