Marshall County, IN Insulation Payback
Marshall County, IN: what topping up your attic actually costs
Marshall County sits in IECC climate zone 5 (Cold) — winters that dominate the energy bill, with cooling a minor factor. For a currently uninsulated attic, DOE and ENERGY STAR recommend building 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 $1,808 a year in heating and cooling — a payback around 1.9 years. That's about as fast as attic paybacks get.
Where the savings come from
The estimated savings split roughly $1,675/year heating, $133/year cooling. Out of every 100 US counties tracked here, Marshall County's savings potential beats roughly 73 of them. Within zone 5 specifically, it ranks 276th of 745 counties by estimated savings. Indiana averages $1,634/year across the counties tracked here; Marshall County comes in 11% higher.
Marshall County's actual weather, not a national average
Marshall County's climate figures — 6,263 heating and 829 cooling degree days a year — are read from PLYMOUTH, IN US, 3.6 miles away, NOAA's nearest 1991-2020 normals station. By total degree days, Marshall County sits at the 73th percentile nationally. Marshall County falls in DOE's moisture regime A (humid), a detail that affects vapor-barrier recommendations more than the R-value target itself.
If the attic isn't bare
If Marshall 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 $264/year — payback about 8.6 years. This one is a genuine toss-up, not a clear yes.
Next steps for a Marshall County attic
Actual quotes will vary by attic access, existing debris, and whether the job needs air sealing first. Treat the $3,480 figure above as a planning number for Marshall County, not a bid - contractors typically charge a $600 minimum regardless of job size.
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.