Suffolk County, NY Insulation Payback
Suffolk County attic insulation, by the numbers
Suffolk County, New York is zone 4 under DOE's climate map (Mixed-Humid), which means a genuine mix of cold winters and humid summers, with neither one dominating the bill. 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 2.4 years at an estimated $1,464/year saved. Topping up the attic pays for itself fast here.
Where the savings come from
Split it out and it's roughly $1,312 a year on the heating side, $152 on cooling. By estimated insulation savings, Suffolk County lands in the 50th percentile nationally. Zone 4 alone covers 825 counties in this dataset, and Suffolk County comes in 250th by savings. New York averages $1,948/year across the counties tracked here; Suffolk County comes in 25% lower.
The climate data behind this
Suffolk County's climate figures — 4,906 heating and 945 cooling degree days a year — are read from RIVERHEAD RSCH FARM, NY US, 1.8 miles away, NOAA's nearest 1991-2020 normals station. That combined heating-and-cooling load ranks Suffolk County 1630th nationally by total degree days — the 48th percentile. One local detail the R-value alone won't tell you: Suffolk County sits in moisture regime A (humid), which can affect the vapor-barrier choice.
If the attic isn't bare
A shallower starting point changes the math: with R-11 already down, only the gap to R-49 needs filling, at roughly $2,280 for an estimated $213/year saved (~10.7-year payback). Call this borderline rather than a clear win.
Next steps for a Suffolk County attic
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 Suffolk County's estimated $1,464/year on the line.
Where these figures come from
Suffolk 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.