Canyon County, ID Insulation Payback
Canyon County, ID: what topping up your attic actually costs
Canyon County, Idaho 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. 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 $1,537 a year — payback in roughly 2.3 years.
That's about as fast as attic paybacks get.
The breakdown behind the number
The estimated savings split roughly $1,414/year heating, $124/year cooling. Out of every 100 US counties tracked here, Canyon County's savings potential beats roughly 55 of them. Within zone 5 specifically, it ranks 714th of 754 counties by estimated savings. Idaho averages $1,995/year across the counties tracked here; Canyon County comes in 23% lower.
Where these numbers come from
The heating and cooling degree days behind this estimate — 5,287 HDD and 771 CDD (base 65°F, 1991-2020 normals) — come from Deer Flat DAM, ID US, the nearest NOAA station with published normals, 3.9 miles from Canyon County's center. That combined heating-and-cooling load ranks Canyon County 1499th nationally by total degree days — the 53rd percentile. Canyon County falls in DOE's moisture regime B (dry), a detail that affects vapor-barrier recommendations more than the R-value target itself.
If the attic isn't bare
If Canyon 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 $224/year — payback about 10.2 years. This one is a genuine toss-up, not a clear yes.
Getting it done in Canyon County
Get quotes from at least two local contractors 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 checking upfront given Canyon County's estimated $1,537/year on the line.
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.