Custer County, MT Insulation Payback
Custer County, MT: what topping up your attic actually costs
Custer County sits in IECC climate zone 6 (Cold) — a real winter that drives most of the annual energy bill here. For a currently uninsulated attic, DOE and ENERGY STAR recommend building up to 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 1.6 years at an estimated $2,126/year saved. That's about as fast as attic paybacks get.
Heating vs. cooling in Custer County
The estimated savings split roughly $2,016/year heating, $110/year cooling. Out of every 100 US counties tracked here, Custer County's savings potential beats roughly 87 of them. Within zone 6 specifically, it ranks 271st of 459 counties by estimated savings. Montana averages $2,182/year across the counties tracked here; Custer County comes in 3% lower.
Where these numbers come from
NOAA's MIZPAH 4 NNW, MT US station, 12.5 miles from Custer County, supplies the 7,541 HDD and 682 CDD this estimate runs on. That combined heating-and-cooling load ranks Custer County 375th nationally by total degree days — the 88th percentile. Custer 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 $310/year saved — roughly 7.4 years to break even. That is a solid payback as home upgrades go.
Quotes and materials for this job
Real bids depend on how easy the attic is to reach and whether old insulation needs removing first, so treat $3,480 as a starting estimate for a Custer County job, not a quote. Expect at least a $600 minimum charge from most contractors.
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.