St. John the Baptist Parish, LA Insulation Payback
St. John the Baptist Parish attic insulation, by the numbers
St. John the Baptist Parish sits in IECC climate zone 2 (Hot-Humid) — summers that stay hot and humid while winters barely register on the energy bill. For a currently uninsulated attic, DOE and ENERGY STAR recommend building up to R-49. For an attic around 1,000 square feet, closing the gap from R-2 to R-49 costs around $2,820 and saves an estimated $813 a year — payback in roughly 3.5 years. Topping up the attic pays for itself here.
Heating vs. cooling in St. John the Baptist Parish
Split it out and it's roughly $356 a year on the heating side, $457 on cooling. By estimated insulation savings, St. John the Baptist Parish lands in the 5th percentile nationally. Zone 2 alone covers 233 counties in this dataset, and St. John the Baptist Parish comes in 159th by savings. Louisiana averages $906/year across the counties tracked here; St. John the Baptist Parish comes in 10% lower.
Where these numbers come from
St. John the Baptist Parish's climate figures — 1,342 heating and 2,870 cooling degree days a year — are read from RESERVE, LA US, 8.1 miles away, NOAA's nearest 1991-2020 normals station. Combined heating and cooling load puts St. John the Baptist Parish in the 5th percentile of this 3,162-county dataset. One local detail the R-value alone won't tell you: St. John the Baptist Parish sits in moisture regime A (humid), which can affect the vapor-barrier choice.
The smaller top-up scenario
If St. John the Baptist Parish's attic already has 3-4 inches of old insulation (about R-11) rather than bare joists, the recommended target drops to R-38. That smaller top-up costs around $1,620 and saves an estimated $110/year — payback about 14.8 years. Call this borderline rather than a clear win.
Getting it done in St. John the Baptist Parish
Actual quotes will vary by attic access, existing debris, and whether the job needs air sealing first. Treat the $2,820 figure above as a planning number for St. John the Baptist Parish, not a bid - contractors typically charge a $600 minimum regardless of job size.
Where these figures come from
St. John the Baptist Parish's R-49 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-49 is the target here specifically.