Silver Bow County, MT Insulation Payback
Silver Bow County, MT: what topping up your attic actually costs
Silver Bow County, Montana is zone 6 under DOE's climate map (Cold), which means a real winter that drives most of the annual energy bill here. An uninsulated attic there should be built 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 1.4 years at an estimated $2,454/year saved. That's about as fast as attic paybacks get.
Where the savings come from
The estimated savings split roughly $2,441/year heating, $13/year cooling. Out of every 100 US counties tracked here, Silver Bow County's savings potential beats roughly 97 of them. Within zone 6 specifically, it ranks 20th of 459 counties by estimated savings. Montana averages $2,182/year across the counties tracked here; Silver Bow County comes in 12% higher.
Silver Bow County's actual weather, not a national average
NOAA's BUTTE BERT MOONEY AP, MT US station, 9 miles from Silver Bow County, supplies the 9,129 HDD and 83 CDD this estimate runs on. Combined heating and cooling load puts Silver Bow County in the 96th percentile of this 3,162-county dataset. Silver Bow County falls in DOE's moisture regime B (dry), a detail that affects vapor-barrier recommendations more than the R-value target itself.
Already have some insulation?
Already have a few inches up there? Topping R-11 up to R-49 runs about $2,280 for about $358/year saved — roughly 6.4 years to break even. That is a solid payback as home upgrades go.
Next steps for a Silver Bow County attic
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 Silver Bow County, not a bid - contractors typically charge a $600 minimum regardless of job size.
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.