McLennan County, TX Insulation Payback
Attic insulation payback for McLennan County, TX
McLennan County, Texas is zone 2 under DOE's climate map (Hot-Humid), which means long, muggy summers and mild winters, where cooling dominates the energy bill. An uninsulated attic there should be built up to R-49. For an attic around 1,000 square feet, closing the gap from R-2 to R-49 costs around $2,820 and saves an estimated $998 a year — payback in roughly 2.8 years. Hard to find a home improvement with a faster payback than this.
The breakdown behind the number
Of that, about $564/year comes from reduced heating and $434/year from reduced cooling load through the ceiling. McLennan County beats 17% of the counties in this 3,162-county dataset on estimated insulation savings. Among the 233 counties DOE places in zone 2, McLennan County ranks 5th. Against Texas's own average of $1,035/year, McLennan County runs 4% below that.
Where these numbers come from
The heating and cooling degree days behind this estimate — 2,125 HDD and 2,725 CDD (base 65°F, 1991-2020 normals) — come from WACO DAM, TX US, the nearest NOAA station with published normals, 3.6 miles from McLennan County's center. By total degree days, McLennan County sits at the 21th percentile nationally. DOE also classifies McLennan 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
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 $134/year saved (~12.1-year payback). It is close - the payback only just fits a reasonable timeframe.
Quotes and materials for this job
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 McLennan County's estimated $998/year on the line.
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.