Guilford County, NC Insulation Payback
Guilford County attic insulation, by the numbers
Guilford County, North Carolina is zone 4 under DOE's climate map (Mixed-Humid), which means real heating and real cooling seasons both, roughly balanced across the year. An uninsulated attic there should be built 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 $1,171 a year in heating and cooling — a payback around 3 years. Topping up the attic pays for itself fast here.
Where the savings come from
Split it out and it's roughly $919 a year on the heating side, $252 on cooling. By estimated insulation savings, Guilford County lands in the 29th percentile nationally. Zone 4 alone covers 825 counties in this dataset, and Guilford County comes in 775th by savings. North Carolina averages $1,169/year across the counties tracked here; Guilford County comes in 0% higher.
The climate data behind this
Guilford County's climate figures — 3,438 heating and 1,567 cooling degree days a year — are read from GREENSBORO WTP, NC US, 0.9 miles away, NOAA's nearest 1991-2020 normals station. By total degree days, Guilford County sits at the 26th percentile nationally. One local detail the R-value alone won't tell you: Guilford County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
If the attic isn't bare
Already have a few inches up there? Topping R-11 up to R-49 runs about $2,280 for about $171/year saved — roughly 13.3 years to break even. Call this borderline rather than a clear win.
Getting it done in Guilford County
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 Guilford County's estimated $1,171/year on the line.
Where these figures come from
Guilford 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.