Park County, MT Insulation Payback
Park County, MT: what topping up your attic actually costs
DOE classifies Park County as climate zone 6, cold — a real winter that drives most of the annual energy bill here. Its recommended attic R-value for bare joists is 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 $1,984 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 $1,946/year heating, $38/year cooling. Out of every 100 US counties tracked here, Park County's savings potential beats roughly 81 of them. Within zone 6 specifically, it ranks 407th of 459 counties by estimated savings. Montana averages $2,182/year across the counties tracked here; Park County comes in 9% lower.
The climate data behind this
The heating and cooling degree days behind this estimate — 7,278 HDD and 239 CDD (base 65°F, 1991-2020 normals) — come from LIVINGSTON 12 S, MT US, the nearest NOAA station with published normals, 2.5 miles from Park County's center. By total degree days, Park County sits at the 79th percentile nationally. Park 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 Park 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 $289/year — payback about 7.9 years. 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 Park 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.