Gillespie County, TX Insulation Payback
Attic insulation payback for Gillespie County, TX
DOE classifies Gillespie County as climate zone 3, hot-humid — long, muggy summers and mild winters, where cooling dominates the energy bill. Its recommended attic R-value for bare joists is 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 $953 a year in heating and cooling — a payback around 3 years. Hard to find a home improvement with a faster payback than this.
The breakdown behind the number
Of that, about $574/year comes from reduced heating and $380/year from reduced cooling load through the ceiling. Gillespie County beats 13% of the counties in this 3,162-county dataset on estimated insulation savings. Among the 690 counties DOE places in zone 3, Gillespie County ranks 565th. Against Texas's own average of $1,035/year, Gillespie County runs 8% below that.
Gillespie County's actual weather, not a national average
The heating and cooling degree days behind this estimate — 2,163 HDD and 2,382 CDD (base 65°F, 1991-2020 normals) — come from FREDERICKSBURG, TX US, the nearest NOAA station with published normals, 6.3 miles from Gillespie County's center. That combined heating-and-cooling load ranks Gillespie County 2762nd nationally by total degree days — the 13th percentile. DOE also classifies Gillespie County as moisture regime A (humid) - ask a local contractor whether that changes the vapor-barrier approach for this job.
The smaller top-up scenario
If Gillespie County'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 $128/year — payback about 12.6 years. It is close - the payback only just fits a reasonable timeframe.
Getting it done in Gillespie County
Real bids depend on how easy the attic is to reach and whether old insulation needs removing first, so treat $2,820 as a starting estimate for a Gillespie County job, not a quote. Expect at least a $600 minimum charge from most contractors.
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.