Johnson County, KY Insulation Payback
Johnson County, KY: what topping up your attic actually costs
Johnson County, Kentucky is zone 4 under DOE's climate map (Mixed-Humid), which means heating load in winter and cooling load in summer, both worth taking seriously here. An uninsulated attic there should be built up to R-60. Topping up a typical 1,000-square-foot attic from bare joists (R-2) to R-60 runs an estimated $3,480, and saves about $1,407 a year in heating and cooling — a payback around 2.5 years. That's about as fast as attic paybacks get.
Where the savings come from
The estimated savings split roughly $1,231/year heating, $176/year cooling. Out of every 100 US counties tracked here, Johnson County's savings potential beats roughly 46 of them. Within zone 4 specifically, it ranks 374th of 825 counties by estimated savings. Kentucky averages $1,385/year across the counties tracked here; Johnson County comes in 2% higher.
The climate data behind this
The heating and cooling degree days behind this estimate — 4,604 HDD and 1,095 CDD (base 65°F, 1991-2020 normals) — come from PAINTSVILLE 1E, KY US, the nearest NOAA station with published normals, 3.1 miles from Johnson County's center. By total degree days, Johnson County sits at the 45th percentile nationally. Johnson County falls in DOE's moisture regime A (humid), a detail that affects vapor-barrier recommendations more than the R-value target itself.
The smaller top-up scenario
If Johnson 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 $205/year — payback about 11.1 years. This one is a genuine toss-up, not a clear yes.
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.