North Slope Borough attic insulation, by the numbers

North Slope Borough, Alaska is zone 8 under DOE's climate map (Subarctic), which means winters severe enough to sit in DOE's most extreme US climate category. 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 $5,016 a year in heating and cooling — a payback around 0.7 years. Topping up the attic pays for itself fast here.

The breakdown behind the number

Cooling barely factors in here; essentially the full $5,016/year is heating savings. By estimated insulation savings, North Slope Borough lands in the 100th percentile nationally. Zone 8 alone covers 9 counties in this dataset, and North Slope Borough comes in 1st by savings. Alaska averages $2,854/year across the counties tracked here; North Slope Borough comes in 76% higher.

Where these numbers come from

The heating and cooling degree days behind this estimate — 18,759 HDD and 1 CDD (base 65°F, 1991-2020 normals) — come from NUIQSUT AP, AK US, the nearest NOAA station with published normals, 79 miles from North Slope Borough's center. That combined heating-and-cooling load ranks North Slope Borough 1st nationally by total degree days — the 100th percentile.

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 $732/year saved — roughly 3.1 years to break even. Worth doing on the numbers alone.

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 North Slope Borough, not a bid - contractors typically charge a $600 minimum regardless of job size.

Where these figures come from

North Slope Borough'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.