Clark County, IN Insulation Payback
Attic insulation payback for Clark County, IN
DOE classifies Clark 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. 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 $1,371 a year in heating and cooling — a payback around 2.5 years. Hard to find a home improvement with a faster payback than this.
Heating vs. cooling in Clark County
Of that, about $1,107/year comes from reduced heating and $264/year from reduced cooling load through the ceiling. Clark County beats 44% of the counties in this 3,162-county dataset on estimated insulation savings. Among the 825 counties DOE places in zone 4, Clark County ranks 441st. Against Indiana's own average of $1,634/year, Clark County runs 16% below that.
Clark County's actual weather, not a national average
The heating and cooling degree days behind this estimate — 4,141 HDD and 1,642 CDD (base 65°F, 1991-2020 normals) — come from LOUISVILLE MCALPINE, KY US, the nearest NOAA station with published normals, 14.4 miles from Clark County's center. That combined heating-and-cooling load ranks Clark County 1681st nationally by total degree days — the 47th percentile. DOE also classifies Clark County as moisture regime A (humid) - ask a local contractor whether that changes the vapor-barrier approach for this job.
If the attic isn't bare
If Clark 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 $200/year — payback about 11.4 years. It is close - the payback only just fits a reasonable timeframe.
Next steps for a Clark County attic
Get more than one quote before committing. Attic access and any needed air sealing move the price around, and most contractors won't take a job below roughly $600 regardless of size - worth asking upfront given Clark County's estimated $1,371/year on the line.
More on how this was built
Nothing here is a guess: the methodology guide names the DOE climate map and NOAA station data behind every number on this page. See the DIY vs. contractor guide for whether a job this size is realistic to do yourself.