Jerome County, ID Insulation Payback
Jerome County, ID: what topping up your attic actually costs
Jerome County sits in IECC climate zone 5 (Cold) — winters that dominate the energy bill, with cooling a minor factor. For a currently uninsulated attic, DOE and Energy Star recommend building up to 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 $1,829 a year in heating and cooling — a payback around 1.9 years.
That's about as fast as attic paybacks get.
The breakdown behind the number
The estimated savings split roughly $1,739/year heating, $90/year cooling. Out of every 100 US counties tracked here, Jerome County's savings potential beats roughly 74 of them. Within zone 5 specifically, it ranks 244th of 754 counties by estimated savings. Idaho averages $1,995/year across the counties tracked here; Jerome County comes in 8% lower.
Jerome County's actual weather, not a national average
The heating and cooling degree days behind this estimate — 6,502 HDD and 562 CDD (base 65°F, 1991-2020 normals) — come from Hazelton, ID US, the nearest NOAA station with published normals, 9.1 miles from Jerome County's center. That combined heating-and-cooling load ranks Jerome County 867th nationally by total degree days — the 73rd percentile. Jerome 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
Already have a few inches up there? Topping R-11 up to R-49 runs about $2,280 for about $267/year saved — roughly 8.5 years to break even. This one is a genuine toss-up, not a clear yes.
Getting it done in Jerome 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 Jerome County's estimated $1,829/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.