Lajas Municipio, PR Insulation Payback
Attic insulation payback for Lajas Municipio, PR
Lajas 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. Topping up a typical 1,000-square-foot attic from bare joists (R-2) to R-30 runs an estimated $1,680, and saves about $893 a year in heating and cooling — a payback around 1.9 years. Hard to find a home improvement with a faster payback than this.
Where the savings come from
Of that, about $0/year comes from reduced heating and $893/year from reduced cooling load through the ceiling. Lajas Municipio beats 10% of the counties in this 3,162-county dataset on estimated insulation savings. Among the 81 counties DOE places in zone 1, Lajas Municipio ranks 8th. Against Puerto Rico's own average of $660/year, Lajas Municipio runs 35% above that.
The climate data behind this
Lajas Municipio's climate figures — 0 heating and 5,758 cooling degree days a year — are read from MAGUEYES IS, PR RQ, 0.6 miles away, NOAA's nearest 1991-2020 normals station. That combined heating-and-cooling load ranks Lajas Municipio 1700th nationally by total degree days — the 46th percentile. DOE also classifies Lajas Municipio as moisture regime A (humid) - ask a local contractor whether that changes the vapor-barrier approach for this job.
Already have some insulation?
Already have a few inches up there? Topping R-11 up to R-25 runs about $840 for about $97/year saved — roughly 8.6 years to break even. It is close - the payback only just fits a reasonable timeframe.
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 Lajas Municipio, not a bid - contractors typically charge a $600 minimum regardless of job size.
More on how this was built
Nothing here is a guess: the methodology guide names the DOE climate map and NOAA station data behind every number on this page. See the DIY vs. contractor guide for whether a job this size is realistic to do yourself.