Blaine County, MT Insulation Payback
Attic insulation payback for Blaine County, MT
Blaine 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. 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 $2,322 a year — payback in roughly 1.5 years. Hard to find a home improvement with a faster payback than this.
Where the savings come from
Of that, about $2,266/year comes from reduced heating and $56/year from reduced cooling load through the ceiling. Blaine County beats 94% of the counties in this 3,162-county dataset on estimated insulation savings. Among the 459 counties DOE places in zone 6, Blaine County ranks 82nd. Against Montana's own average of $2,182/year, Blaine County runs 6% above that.
Where these numbers come from
Blaine County's climate figures — 8,474 heating and 347 cooling degree days a year — are read from FT BELKNAP 2 SW, MT US, 9 miles away, NOAA's nearest 1991-2020 normals station. Combined heating and cooling load puts Blaine County in the 94th percentile of this 3,162-county dataset. DOE also classifies Blaine County as moisture regime B (dry) - ask a local contractor whether that changes the vapor-barrier approach for this job.
The smaller top-up scenario
If Blaine 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 $339/year — payback about 6.7 years. Topping up the attic pays for itself here.
Getting it done in Blaine County
Actual quotes will vary by attic access, existing debris, and whether the job needs air sealing first. Treat the $3,480 figure above as a planning number for Blaine County, not a bid - contractors typically charge a $600 minimum regardless of job size.
More on how this was built
Nothing here is a guess: the methodology guide names the DOE climate map and NOAA station data behind every number on this page. See the DIY vs. contractor guide for whether a job this size is realistic to do yourself.