Marion County, TN Insulation Payback
Attic insulation payback for Marion County, TN
Marion County, Tennessee is zone 4 under DOE's climate map (Mixed-Humid), which means heating load in winter and cooling load in summer, both worth taking seriously here. An uninsulated attic there should be built up to R-60. For an attic around 1,000 square feet, closing the gap from R-2 to R-60 costs around $3,480 and saves an estimated $1,126 a year — payback in roughly 3.1 years. Worth doing on the numbers alone.
Heating vs. cooling in Marion County
Of that, about $876/year comes from reduced heating and $250/year from reduced cooling load through the ceiling. Marion County beats 26% of the counties in this 3,162-county dataset on estimated insulation savings. Among the 825 counties DOE places in zone 4, Marion County ranks 803rd. Against Tennessee's own average of $1,258/year, Marion County runs 10% below that.
Where these numbers come from
The heating and cooling degree days behind this estimate — 3,276 HDD and 1,554 CDD (base 65°F, 1991-2020 normals) — come from WHITWELL-SEQUATCHIE VLY, TN US, the nearest NOAA station with published normals, 13.5 miles from Marion County's center. That combined heating-and-cooling load ranks Marion County 2510th nationally by total degree days — the 21th percentile. DOE also classifies Marion County as moisture regime A (humid) - ask a local contractor whether that changes the vapor-barrier approach for this job.
If the attic isn't bare
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 $164/year saved (~13.9-year payback). It is close - the payback only just fits a reasonable timeframe.
Getting it done in Marion County
Actual quotes will vary by attic access, existing debris, and whether the job needs air sealing first. Treat the $3,480 figure above as a planning number for Marion County, not a bid - contractors typically charge a $600 minimum regardless of job size.
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.