Guánica Municipio, PR Insulation Payback
Guánica Municipio attic insulation, by the numbers
DOE classifies Guánica Municipio as climate zone 1, hot-humid — humid heat for much of the year, with cooling running far more than heating ever does. Its recommended attic R-value for bare joists is R-30. For an attic around 1,000 square feet, closing the gap from R-2 to R-30 costs around $1,680 and saves an estimated $893 a year — payback in roughly 1.9 years. Topping up the attic pays for itself fast here.
Where the savings come from
Split it out and it's roughly $0 a year on the heating side, $893 on cooling. By estimated insulation savings, Guánica Municipio lands in the 10th percentile nationally. Zone 1 alone covers 81 counties in this dataset, and Guánica Municipio comes in 7th by savings. Puerto Rico averages $660/year across the counties tracked here; Guánica Municipio comes in 35% higher.
Where these numbers come from
NOAA's MAGUEYES IS, PR RQ station, 8.3 miles from Guánica Municipio, supplies the 0 HDD and 5,758 CDD this estimate runs on. That combined heating-and-cooling load ranks Guánica Municipio 1699th nationally by total degree days — the 46th percentile. One local detail the R-value alone won't tell you: Guánica Municipio sits in moisture regime A (humid), which can affect the vapor-barrier choice.
If the attic isn't bare
If Guánica Municipio's attic already has 3-4 inches of old insulation (about R-11) rather than bare joists, the recommended target drops to R-25. That smaller top-up costs around $840 and saves an estimated $97/year — payback about 8.6 years. Call this borderline rather than a clear win.
Getting it done in Guánica Municipio
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 Guánica Municipio's estimated $893/year on the line.
Where these figures come from
Guánica Municipio's R-30 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-30 is the target here specifically.