Bristol County, MA Insulation Payback
Bristol County attic insulation, by the numbers
Bristol County, Massachusetts is zone 5 under DOE's climate map (Cold), which means winters that dominate the energy bill, with cooling a minor factor. An uninsulated attic there should be built up to R-60. Going from R-2 to the recommended R-60 costs roughly $3,480 installed for a typical attic (about 1,000 sq ft), and pays for itself in about 2.1 years at an estimated $1,660/year saved. Topping up the attic pays for itself fast here.
Heating vs. cooling in Bristol County
Split it out and it's roughly $1,567 a year on the heating side, $93 on cooling. By estimated insulation savings, Bristol County lands in the 63th percentile nationally. Zone 5 alone covers 745 counties in this dataset, and Bristol County comes in 554th by savings. Massachusetts averages $1,728/year across the counties tracked here; Bristol County comes in 4% lower.
The climate data behind this
The heating and cooling degree days behind this estimate — 5,860 HDD and 577 CDD (base 65°F, 1991-2020 normals) — come from NEW BEDFORD MUNI AP, MA US, the nearest NOAA station with published normals, 8.4 miles from Bristol County's center. By total degree days, Bristol County sits at the 61th percentile nationally. One local detail the R-value alone won't tell you: Bristol County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
The smaller top-up scenario
If Bristol 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 $242/year — payback about 9.4 years. Call this borderline rather than a clear win.
Getting it done in Bristol County
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 Bristol County, not a bid - contractors typically charge a $600 minimum regardless of job size.
Where these figures come from
Bristol 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.