Durham County, NC Insulation Payback
Attic insulation payback for Durham County, NC
Durham County sits in IECC climate zone 4 (Mixed-Humid) — heating load in winter and cooling load in summer, both worth taking seriously here. For a currently uninsulated attic, DOE and ENERGY STAR recommend building up to R-60. For an attic around 1,000 square feet, closing the gap from R-2 to R-60 costs around $3,480 and saves an estimated $1,220 a year — payback in roughly 2.9 years. Hard to find a home improvement with a faster payback than this.
The breakdown behind the number
Of that, about $1,003/year comes from reduced heating and $217/year from reduced cooling load through the ceiling. Durham County beats 33% of the counties in this 3,162-county dataset on estimated insulation savings. Among the 825 counties DOE places in zone 4, Durham County ranks 722nd. Against North Carolina's own average of $1,169/year, Durham County runs 4% above that.
The climate data behind this
The heating and cooling degree days behind this estimate — 3,750 HDD and 1,350 CDD (base 65°F, 1991-2020 normals) — come from DURHAM, NC US, the nearest NOAA station with published normals, 4.8 miles from Durham County's center. Combined heating and cooling load puts Durham County in the 29th percentile of this 3,162-county dataset. DOE also classifies Durham County as moisture regime A (humid) - ask a local contractor whether that changes the vapor-barrier approach for this job.
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 $178/year saved — roughly 12.8 years to break even. It is close - the payback only just fits a reasonable timeframe.
Quotes and materials for this job
Actual quotes will vary by attic access, existing debris, and whether the job needs air sealing first. Treat the $3,480 figure above as a planning number for Durham County, not a bid - contractors typically charge a $600 minimum regardless of job size.
More on how this was built
Nothing here is a guess: the methodology guide names the DOE climate map and NOAA station data behind every number on this page. See the DIY vs. contractor guide for whether a job this size is realistic to do yourself.