Harris County, GA Insulation Payback
Harris County attic insulation, by the numbers
Harris County, Georgia is zone 3 under DOE's climate map (Mixed-Humid), which means real heating and real cooling seasons both, roughly balanced across the year. An uninsulated attic there should be built 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 $930 a year in heating and cooling — a payback around 3 years. Topping up the attic pays for itself here.
Heating vs. cooling in Harris County
Split it out and it's roughly $604 a year on the heating side, $327 on cooling. By estimated insulation savings, Harris County lands in the 12th percentile nationally. Zone 3 alone covers 690 counties in this dataset, and Harris County comes in 613th by savings. Georgia averages $974/year across the counties tracked here; Harris County comes in 5% lower.
Harris County's actual weather, not a national average
NOAA's MULBERRY GROVE, GA US station, 12.7 miles from Harris County, supplies the 2,275 HDD and 2,051 CDD this estimate runs on. Combined heating and cooling load puts Harris County in the 7th percentile of this 3,162-county dataset. 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 $125/year saved (~12.9-year payback). Call this borderline rather than a clear win.
Quotes and materials for this job
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 Harris County job, not a quote. Expect at least a $600 minimum charge from most contractors.
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.