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 3,171-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, so treat the $2,820 figure above as a planning number for St. John the Baptist Parish, not a bid. Worth getting quotes from at least two local contractors before committing - most 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.