Fremont County, ID Insulation Payback
Is attic insulation worth it in Fremont County, ID?
DOE classifies Fremont 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. 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 $2,184 a year — payback in roughly 1.6 years. Few home upgrades pay back that quickly.
Where the savings come from
Heating accounts for about $2,151/year of that and cooling about $34/year — Fremont County needs both. Nationally, Fremont County ranks in the 90th percentile for insulation savings potential. Compared only against its own climate zone, Fremont County places 202nd out of 459. Against Idaho's own average of $1,995/year, Fremont County runs 9% above that.
Where these numbers come from
NOAA's ASHTON 1N, ID US station, 10.3 miles from Fremont County, supplies the 8,043 HDD and 210 CDD this estimate runs on. That combined heating-and-cooling load ranks Fremont County 357th nationally by total degree days — the 89th percentile. Its moisture regime is classified dry, 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
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 $319/year saved (~7.2-year payback). The math clears comfortably within a normal ownership horizon.
Quotes and materials for this job
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 Fremont County, not a bid - contractors typically charge a $600 minimum regardless of job size.
Fremont County's numbers, sourced
The methodology guide lists exactly which DOE and NOAA sources feed Fremont 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.