Murray County, GA Insulation Payback
Attic insulation payback for Murray County, GA
DOE classifies Murray County as climate zone 4, mixed-humid — heating load in winter and cooling load in summer, both worth taking seriously here. Its recommended attic R-value for bare joists is R-60. Going from R-2 to the recommended R-60 costs roughly $3,480 installed for a typical attic (about 1,000 sq ft), and pays for itself in about 3 years at an estimated $1,146/year saved. Worth doing on the numbers alone.
The breakdown behind the number
Of that, about $895/year comes from reduced heating and $252/year from reduced cooling load through the ceiling. Murray County beats 27% of the counties in this 3,162-county dataset on estimated insulation savings. Among the 825 counties DOE places in zone 4, Murray County ranks 795th. Against Georgia's own average of $974/year, Murray County runs 18% above that.
The climate data behind this
NOAA's CHATSWORTH 2, GA US station, 3.1 miles from Murray County, supplies the 3,346 HDD and 1,566 CDD this estimate runs on. That combined heating-and-cooling load ranks Murray County 2429th nationally by total degree days — the 23th percentile. DOE also classifies Murray 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-49 needs filling, at roughly $2,280 for an estimated $167/year saved (~13.6-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 Murray County's estimated $1,146/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.