New Hanover County, NC Insulation Payback
New Hanover County attic insulation, by the numbers
New Hanover County sits in IECC climate zone 3 (Hot-Humid) — long, muggy summers and mild winters, where cooling dominates the energy bill. For a currently uninsulated attic, DOE and ENERGY STAR recommend building up to R-49. Going from R-2 to the recommended R-49 costs roughly $2,820 installed for a typical attic (about 1,000 sq ft), and pays for itself in about 2.9 years at an estimated $985/year saved. Topping up the attic pays for itself fast here.
The breakdown behind the number
Split it out and it's roughly $645 a year on the heating side, $340 on cooling. By estimated insulation savings, New Hanover County lands in the 16th percentile nationally. Zone 3 alone covers 690 counties in this dataset, and New Hanover County comes in 501st by savings. North Carolina averages $1,169/year across the counties tracked here; New Hanover County comes in 16% lower.
The climate data behind this
The heating and cooling degree days behind this estimate — 2,431 HDD and 2,131 CDD (base 65°F, 1991-2020 normals) — come from WILMINGTON 7 SE, NC US, the nearest NOAA station with published normals, 3 miles from New Hanover County's center. That combined heating-and-cooling load ranks New Hanover County 2752nd nationally by total degree days — the 13th percentile. One local detail the R-value alone won't tell you: New Hanover County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
Already have some insulation?
If New Hanover 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 $133/year — payback about 12.2 years. Call this borderline rather than a clear win.
Getting it done in New Hanover 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 New Hanover County's estimated $985/year on the line.
Where these figures come from
New Hanover 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.