Llano County, TX Insulation Payback
Is attic insulation worth it in Llano County, TX?
Llano County sits in IECC climate zone 3 (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-49. Topping up a typical 1,000-square-foot attic from bare joists (R-2) to R-49 runs an estimated $2,820, and saves about $980 a year in heating and cooling — a payback around 2.9 years.
Few home upgrades pay back that quickly.
The breakdown behind the number
Heating accounts for about $534/year of that and cooling about $446/year — Llano County needs both. Nationally, Llano County ranks in the 15th percentile for insulation savings potential. Compared only against its own climate zone, Llano County places 510th out of 690. Against Texas's own average of $1,035/year, Llano County runs 5% below that.
Where these numbers come from
The heating and cooling degree days behind this estimate — 2,014 HDD and 2,799 CDD (base 65°F, 1991-2020 normals) — come from Llano, TX US, the nearest NOAA station with published normals, 3 miles from Llano County's center. That combined heating-and-cooling load ranks Llano County 2542nd nationally by total degree days — the 20th percentile. Its moisture regime is classified humid, which matters for whether the attic needs a vapor retarder as part of the job — worth asking a contractor about locally.
The smaller top-up scenario
A shallower starting point changes the math: with R-11 already down, only the gap to R-38 needs filling, at roughly $1,620 for an estimated $132/year saved (~12.3-year payback). Whether that is worth it depends on how long you plan to stay.
Getting it done in Llano County
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 Llano County, not a bid. Worth getting quotes from at least two local contractors before committing - most charge a $600 minimum regardless of job size.
Llano County's numbers, sourced
The methodology guide lists exactly which DOE and NOAA sources feed Llano County's numbers, and where the cost assumptions come from. See the DIY vs. contractor guide for whether a job this size is realistic to do yourself.