Bonner County, ID Insulation Payback
Bonner County, ID: what topping up your attic actually costs
Bonner County, Idaho is zone 6 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. 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 $1,932 a year — payback in roughly 1.8 years. That's about as fast as attic paybacks get.
Where the savings come from
The estimated savings split roughly $1,895/year heating, $37/year cooling. Out of every 100 US counties tracked here, Bonner County's savings potential beats roughly 79 of them. Within zone 6 specifically, it ranks 435th of 459 counties by estimated savings. Idaho averages $1,995/year across the counties tracked here; Bonner County comes in 3% lower.
The climate data behind this
NOAA's SANDPOINT EXP STN, ID US station, 3.6 miles from Bonner County, supplies the 7,087 HDD and 233 CDD this estimate runs on. That combined heating-and-cooling load ranks Bonner County 736th nationally by total degree days — the 77th percentile. Bonner County falls in DOE's moisture regime B (dry), a detail that affects vapor-barrier recommendations more than the R-value target itself.
Already have some insulation?
If Bonner County's attic already has 3-4 inches of old insulation (about R-11) rather than bare joists, the recommended target drops to R-49. That smaller top-up costs around $2,280 and saves an estimated $282/year — payback about 8.1 years. This one is a genuine toss-up, not a clear yes.
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 Bonner County, not a bid - contractors typically charge a $600 minimum regardless of job size.
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.