Harris County attic insulation, by the numbers

DOE classifies Harris County as climate zone 2, 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. 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 $860 a year — payback in roughly 3.3 years. Topping up the attic pays for itself here.

The breakdown behind the number

Split it out and it's roughly $336 a year on the heating side, $524 on cooling. By estimated insulation savings, Harris County lands in the 7th percentile nationally. Zone 2 alone covers 233 counties in this dataset, and Harris County comes in 97th by savings. Texas averages $1,035/year across the counties tracked here; Harris County comes in 17% lower.

Where these numbers come from

NOAA's HOUSTON INTERCONT AP, TX US station, 8.7 miles from Harris County, supplies the 1,266 HDD and 3,288 CDD this estimate runs on. That combined heating-and-cooling load ranks Harris County 2756th nationally by total degree days — the 13th percentile. One local detail the R-value alone won't tell you: Harris County sits in moisture regime A (humid), which can affect the vapor-barrier choice.

Already have some insulation?

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 $116/year saved (~14-year payback). Call this borderline rather than a clear win.

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 $2,820 figure above as a planning number for Harris County, not a bid - contractors typically charge a $600 minimum regardless of job size.

Where these figures come from

Harris County's R-49 target and its degree-day figures both come from named federal sources - see the methodology guide for exactly which ones. The guide to what R-value actually means explains why R-49 is the target here specifically.