Carter County, OK Insulation Payback
Carter County attic insulation, by the numbers
DOE classifies Carter County as climate zone 3, mixed-humid — a genuine mix of cold winters and humid summers, with neither one dominating the bill. Its recommended attic R-value for bare joists is R-49. For an attic around 1,000 square feet, closing the gap from R-2 to R-49 costs around $2,820 and saves an estimated $1,121 a year — payback in roughly 2.5 years. Topping up the attic pays for itself fast here.
Where the savings come from
Split it out and it's roughly $767 a year on the heating side, $354 on cooling. By estimated insulation savings, Carter County lands in the 26th percentile nationally. Zone 3 alone covers 690 counties in this dataset, and Carter County comes in 207th by savings. Oklahoma averages $1,260/year across the counties tracked here; Carter County comes in 11% lower.
Where these numbers come from
The heating and cooling degree days behind this estimate — 2,891 HDD and 2,220 CDD (base 65°F, 1991-2020 normals) — come from ARDMORE 7WNW MESONET, OK US, the nearest NOAA station with published normals, 5.2 miles from Carter County's center. By total degree days, Carter County sits at the 29th percentile nationally. One local detail the R-value alone won't tell you: Carter County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
If the attic isn't bare
If Carter County's attic already has 3-4 inches of old insulation (about R-11) rather than bare joists, the recommended target drops to R-38. That smaller top-up costs around $1,620 and saves an estimated $151/year — payback about 10.7 years. Call this borderline rather than a clear win.
Next steps for a Carter County attic
Real bids depend on how easy the attic is to reach and whether old insulation needs removing first, so treat $2,820 as a starting estimate for a Carter County job, not a quote. Expect at least a $600 minimum charge from most contractors.
Where these figures come from
Carter County's R-49 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-49 is the target here specifically.