Johnson County, KS Insulation Payback
Johnson County attic insulation, by the numbers
DOE classifies Johnson County as climate zone 4, mixed-humid — heating load in winter and cooling load in summer, both worth taking seriously 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 $1,547 a year — payback in roughly 2.2 years. Topping up the attic pays for itself fast here.
Heating vs. cooling in Johnson County
Split it out and it's roughly $1,325 a year on the heating side, $222 on cooling. By estimated insulation savings, Johnson County lands in the 56th percentile nationally. Zone 4 alone covers 825 counties in this dataset, and Johnson County comes in 103rd by savings. Kansas averages $1,594/year across the counties tracked here; Johnson County comes in 3% lower.
Where these numbers come from
Johnson County's climate figures — 4,957 heating and 1,382 cooling degree days a year — are read from OLATHE 3E, KS US, 3.3 miles away, NOAA's nearest 1991-2020 normals station. Combined heating and cooling load puts Johnson County in the 59th percentile of this 3,162-county dataset. One local detail the R-value alone won't tell you: Johnson County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
The smaller top-up scenario
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 $226/year saved (~10.1-year payback). Call this borderline rather than a clear win.
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.
Where these figures come from
Johnson County's R-60 target and its degree-day figures both come from named federal sources - see the methodology guide for exactly which ones. The guide to what R-value actually means explains why R-60 is the target here specifically.