Greene County, IN Insulation Payback
Greene County, IN: what topping up your attic actually costs
DOE classifies Greene County as climate zone 4, mixed-humid — real heating and real cooling seasons both, roughly balanced across the year. Its recommended attic R-value for bare joists is 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 2.4 years at an estimated $1,447/year saved. That's about as fast as attic paybacks get.
The breakdown behind the number
The estimated savings split roughly $1,236/year heating, $211/year cooling. Out of every 100 US counties tracked here, Greene County's savings potential beats roughly 49 of them. Within zone 4 specifically, it ranks 279th of 825 counties by estimated savings. Indiana averages $1,634/year across the counties tracked here; Greene County comes in 11% lower.
Greene County's actual weather, not a national average
The heating and cooling degree days behind this estimate — 4,622 HDD and 1,314 CDD (base 65°F, 1991-2020 normals) — come from ELNORA, IN US, the nearest NOAA station with published normals, 13.1 miles from Greene County's center. That combined heating-and-cooling load ranks Greene County 1573rd nationally by total degree days — the 50th percentile. Greene 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
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 $211/year saved (~10.8-year payback). This one is a genuine toss-up, not a clear yes.
Getting it done in Greene County
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 Greene 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.