Santa Isabel Municipio, PR Insulation Payback
Santa Isabel Municipio, PR: what topping up your attic actually costs
Santa Isabel Municipio sits in IECC climate zone 1 (Hot-Humid) — humid heat for much of the year, with cooling running far more than heating ever does. For a currently uninsulated attic, DOE and ENERGY STAR recommend building up to 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 $729 a year — payback in roughly 2.3 years. That's about as fast as attic paybacks get.
The breakdown behind the number
The estimated savings split roughly $0/year heating, $729/year cooling. Out of every 100 US counties tracked here, Santa Isabel Municipio's savings potential beats roughly 3 of them. Within zone 1 specifically, it ranks 36th of 81 counties by estimated savings. Puerto Rico averages $660/year across the counties tracked here; Santa Isabel Municipio comes in 10% higher.
Santa Isabel Municipio's actual weather, not a national average
NOAA's PONCE 4 E, PR RQ station, 10.4 miles from Santa Isabel Municipio, supplies the 0 HDD and 4,700 CDD this estimate runs on. Combined heating and cooling load puts Santa Isabel Municipio in the 17th percentile of this 3,162-county dataset. Santa Isabel Municipio falls in DOE's moisture regime A (humid), a detail that affects vapor-barrier recommendations more than the R-value target itself.
The smaller top-up scenario
Already have a few inches up there? Topping R-11 up to R-25 runs about $840 for about $80/year saved — roughly 10.6 years to break even. This one is a genuine toss-up, not a clear yes.
Quotes and materials for this job
Actual quotes will vary by attic access, existing debris, and whether the job needs air sealing first. Treat the $1,680 figure above as a planning number for Santa Isabel Municipio, not a bid - contractors typically charge a $600 minimum regardless of job size.
Nothing here is a guess
Every figure on this page traces to DOE/IECC climate zones and NOAA degree-day normals, documented in the methodology guide. The guide to what R-value actually means explains why R-30 is the target here specifically.