Payette County, ID Insulation Payback
Payette County attic insulation, by the numbers
DOE classifies Payette County as climate zone 5, cold — winters that dominate the energy bill, with cooling a minor factor. Its recommended attic R-value for bare joists is R-60. Going from R-2 to the recommended R-60 costs roughly $3,480 installed for a typical attic (about 1,000 sq ft), and pays for itself in about 2.3 years at an estimated $1,540/year saved. Topping up the attic pays for itself fast here.
The breakdown behind the number
Split it out and it's roughly $1,391 a year on the heating side, $149 on cooling. By estimated insulation savings, Payette County lands in the 56th percentile nationally. Zone 5 alone covers 745 counties in this dataset, and Payette County comes in 702nd by savings. Idaho averages $1,995/year across the counties tracked here; Payette County comes in 23% lower.
Where these numbers come from
The heating and cooling degree days behind this estimate — 5,203 HDD and 925 CDD (base 65°F, 1991-2020 normals) — come from PAYETTE, ID US, the nearest NOAA station with published normals, 10.3 miles from Payette County's center. That combined heating-and-cooling load ranks Payette County 1440th nationally by total degree days — the 54th percentile. One local detail the R-value alone won't tell you: Payette County sits in moisture regime B (dry), which can affect the vapor-barrier choice.
The smaller top-up scenario
Already have a few inches up there? Topping R-11 up to R-49 runs about $2,280 for about $225/year saved — roughly 10.2 years to break even. Call this borderline rather than a clear win.
Quotes and materials for this job
Get more than one quote 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 asking upfront given Payette County's estimated $1,540/year on the line.
Where these figures come from
Payette County's R-60 target and its degree-day figures both come from named federal sources - see the methodology guide for exactly which ones. The guide to what R-value actually means explains why R-60 is the target here specifically.