Madison County, ID Insulation Payback
Attic insulation payback for Madison County, ID
Madison County, Idaho is zone 6 under DOE's climate map (Cold), which means winters that dominate the energy bill, with cooling a minor factor. An uninsulated attic there should be built up to 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 $2,090 a year — payback in roughly 1.7 years. Hard to find a home improvement with a faster payback than this.
The breakdown behind the number
Of that, about $2,042/year comes from reduced heating and $48/year from reduced cooling load through the ceiling. Madison County beats 86% of the counties in this 3,162-county dataset on estimated insulation savings. Among the 459 counties DOE places in zone 6, Madison County ranks 303rd. Against Idaho's own average of $1,995/year, Madison County runs 5% above that.
The climate data behind this
The heating and cooling degree days behind this estimate — 7,636 HDD and 299 CDD (base 65°F, 1991-2020 normals) — come from REXBURG BYU IDAHO, ID US, the nearest NOAA station with published normals, 6.7 miles from Madison County's center. By total degree days, Madison County sits at the 85th percentile nationally. DOE also classifies Madison County as moisture regime B (dry) - ask a local contractor whether that changes the vapor-barrier approach for this job.
If the attic isn't bare
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 $305/year saved (~7.5-year payback). Topping up the attic pays for itself here.
Getting it done in Madison County
Actual quotes will vary by attic access, existing debris, and whether the job needs air sealing first. Treat the $3,480 figure above as a planning number for Madison County, not a bid - contractors typically charge a $600 minimum regardless of job size.
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.