Grundy County, MO Insulation Payback
Grundy County, MO: what topping up your attic actually costs
DOE classifies Grundy County as climate zone 5, cold — cold enough that heating, not cooling, is what decides the bill. 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 $1,721 a year in heating and cooling — a payback around 2 years. That's about as fast as attic paybacks get.
Heating vs. cooling in Grundy County
The estimated savings split roughly $1,518/year heating, $202/year cooling. Out of every 100 US counties tracked here, Grundy County's savings potential beats roughly 67 of them. Within zone 5 specifically, it ranks 442nd of 745 counties by estimated savings. Missouri averages $1,534/year across the counties tracked here; Grundy County comes in 12% higher.
Where these numbers come from
Grundy County's climate figures — 5,679 heating and 1,258 cooling degree days a year — are read from TRENTON, MO US, 3.1 miles away, NOAA's nearest 1991-2020 normals station. That combined heating-and-cooling load ranks Grundy County 949th nationally by total degree days — the 70th percentile. Grundy 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 Grundy 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 $251/year — payback about 9.1 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 Grundy 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.