Johnson County, WY Insulation Payback
Johnson County, WY: what topping up your attic actually costs
Johnson County, Wyoming 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. 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 $2,082 a year — payback in roughly 1.7 years. That's about as fast as attic paybacks get.
The breakdown behind the number
The estimated savings split roughly $2,010/year heating, $73/year cooling. Out of every 100 US counties tracked here, Johnson County's savings potential beats roughly 86 of them. Within zone 6 specifically, it ranks 313th of 459 counties by estimated savings. Wyoming averages $2,161/year across the counties tracked here; Johnson County comes in 4% lower.
The climate data behind this
The heating and cooling degree days behind this estimate — 7,516 HDD and 452 CDD (base 65°F, 1991-2020 normals) — come from BILLY CREEK, WY US, the nearest NOAA station with published normals, 9 miles from Johnson County's center. Combined heating and cooling load puts Johnson County in the 85th percentile of this 3,162-county dataset. Johnson 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
A shallower starting point changes the math: with R-11 already down, only the gap to R-49 needs filling, at roughly $2,280 for an estimated $304/year saved (~7.5-year payback). 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 Johnson 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.