Inyo County, CA Insulation Payback
Inyo County attic insulation, by the numbers
DOE classifies Inyo County as climate zone 4, mixed-dry — dry heat in summer giving way to a properly cold winter. Its recommended attic R-value for bare joists is R-60. Topping up a typical 1,000-square-foot attic from bare joists (R-2) to R-60 runs an estimated $3,480, and saves about $1,188 a year in heating and cooling — a payback around 2.9 years. Topping up the attic pays for itself fast here.
Where the savings come from
Split it out and it's roughly $299 a year on the heating side, $889 on cooling. By estimated insulation savings, Inyo County lands in the 30th percentile nationally. Zone 4 alone covers 825 counties in this dataset, and Inyo County comes in 761st by savings. California averages $1,056/year across the counties tracked here; Inyo County comes in 13% higher.
Inyo County's actual weather, not a national average
NOAA's STOVEPIPE WELLS 1 SW, CA US station, 14.6 miles from Inyo County, supplies the 1,119 HDD and 5,533 CDD this estimate runs on. By total degree days, Inyo County sits at the 65th percentile nationally. One local detail the R-value alone won't tell you: Inyo County sits in moisture regime B (dry), 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-49 needs filling, at roughly $2,280 for an estimated $173/year saved (~13.2-year payback). Call this borderline rather than a clear win.
Next steps for a Inyo County attic
Real bids depend on how easy the attic is to reach and whether old insulation needs removing first, so treat $3,480 as a starting estimate for a Inyo County job, not a quote. Expect at least a $600 minimum charge from most contractors.
Where these figures come from
Inyo County's R-60 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-60 is the target here specifically.