Granville County, NC Insulation Payback
Granville County attic insulation, by the numbers
DOE classifies Granville County as climate zone 4, 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-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 $1,205 a year in heating and cooling — a payback around 2.9 years. Topping up the attic pays for itself fast here.
Heating vs. cooling in Granville County
Split it out and it's roughly $956 a year on the heating side, $249 on cooling. By estimated insulation savings, Granville County lands in the 32th percentile nationally. Zone 4 alone covers 825 counties in this dataset, and Granville County comes in 742nd by savings. North Carolina averages $1,169/year across the counties tracked here; Granville County comes in 3% higher.
Where these numbers come from
NOAA's OXFORD AG, NC US station, 2.6 miles from Granville County, supplies the 3,574 HDD and 1,551 CDD this estimate runs on. By total degree days, Granville County sits at the 29th percentile nationally. One local detail the R-value alone won't tell you: Granville County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
The smaller top-up scenario
Already have a few inches up there? Topping R-11 up to R-49 runs about $2,280 for about $176/year saved — roughly 13 years to break even. Call this borderline rather than a clear win.
Next steps for a Granville County attic
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 Granville County job, not a quote. Expect at least a $600 minimum charge from most contractors.
Where these figures come from
Granville County's R-60 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-60 is the target here specifically.