Belknap County, NH Insulation Payback
Belknap County attic insulation, by the numbers
Belknap County sits in IECC climate zone 6 (Cold) — a real winter that drives most of the annual energy bill 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 $1,984 a year — payback in roughly 1.8 years. Topping up the attic pays for itself fast here.
Where the savings come from
Split it out and it's roughly $1,899 a year on the heating side, $85 on cooling. By estimated insulation savings, Belknap County lands in the 81th percentile nationally. Zone 6 alone covers 459 counties in this dataset, and Belknap County comes in 408th by savings. New Hampshire averages $2,071/year across the counties tracked here; Belknap County comes in 4% lower.
The climate data behind this
The heating and cooling degree days behind this estimate — 7,103 HDD and 529 CDD (base 65°F, 1991-2020 normals) — come from LAKEPORT 2, NH US, the nearest NOAA station with published normals, 2.9 miles from Belknap County's center. That combined heating-and-cooling load ranks Belknap County 608th nationally by total degree days — the 81th percentile. One local detail the R-value alone won't tell you: Belknap County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
Already have some insulation?
If Belknap County's attic already has 3-4 inches of old insulation (about R-11) rather than bare joists, the recommended target drops to R-49. That smaller top-up costs around $2,280 and saves an estimated $289/year — payback about 7.9 years. Worth doing on the numbers alone.
Next steps for a Belknap County attic
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 Belknap County, not a bid - contractors typically charge a $600 minimum regardless of job size.
Where these figures come from
Belknap 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.